Pattynama, P.M.T.

Retrograde Transvenous Ethanol Embolization of High-flow Peripheral Arteriovenous Malformations (Article)

2011-09-08T00:00:00Z

Purpose: To report the clinical efficiency and complications in patients treated with retrograde transvenous ethanol embolization of high-flow peripheral arteriovenous malformations (AVMs). Retrograde transvenous ethanol embolization of high-flow AVMs is a technique that can be used to treat AVMs with a dominant outflow vein whenever conventional interventional procedures have proved insufficient. Methods: This is a retrospective study of the clinical effectiveness and complications of retrograde embolization in five patients who had previously undergone multiple arterial embolization procedures without clinical success. Results: Clinical outcomes were good in all patients but were achieved at the cost of serious, although transient, complications in three patients. Conclusion: Retrograde transvenous ethanol embolization is a highly effective therapy for high-flow AVMs. However, because of the high complication rate, it should be reserved as a last resort, to be used after conventional treatment options have failed.

Radial force measurements in carotid stents: Influence of stent design and length of the lesion (Article)

2011-05-01T00:00:00Z

Purpose: To assess the differences in radial force of carotid stents and whether the length of the lesion influences the measurements. Materials and Methods: Different models of tapered stents of similar size (length, 30 mm) were used. The tapered nitinol Acculink, Protg, and Cristallo Ideale carotid artery stents and the straight, braided Elgiloy carotid Wallstent were compared. A measurement device consisting of three film loops along the stent body connected to aluminium rods with copper strain gauges was developed. Five stents of each type were deployed within 3-mm stenoses in simulated long (26 mm) and short (8 mm) stenoses. Results: In the short stenosis simulation, the greatest radial force was seen in the Protg stent, at 3.14 N ± 0.45, followed by the Cristallo Ideale stent (1.73 N ± 0.51), Acculink (1.16 N ± 0.21), and Wallstent (0.84 N ± 0.10; P < .001). In the long stenosis simulation, peak radial force again was highest in the Protg stent (1.67 N ± 0.37), but the Acculink stent was second (0.95 N ± 0.12) and the Wallstent third (0.80 N ± 0.06). The Cristallo Ideale stent, in contrast to the short stenosis simulation, produced the least radial force (0.44 N ± 0.13) in the long stenosis simulation (P = .001). Conclusions: Radial forces exerted by carotid stents vary significantly among stent designs. Differences between stent types are dependent on the length of the stenosis. An understanding of radial force is necessary for a well-considered choice of stent type in each individual patient.

Endoscopic visible light spectroscopy: A new, minimally invasive technique to diagnose chronic GI ischemia (Article)

2011-02-01T00:00:00Z

Background: The diagnosis of chronic GI ischemia (CGI) remains a clinical challenge. Currently, there is no single simple test with high sensitivity available. Visible light spectroscopy (VLS) is a new technique that noninvasively measures mucosal oxygen saturation during endoscopy. Objective: To determine the diagnostic accuracy of VLS for the detection of ischemia in a large cohort of patients. Design: Prospective study, with adherence to the Standards for Reporting of Diagnostic Accuracy. Setting: Tertiary referral center. Patients: Consecutive patients referred for evaluation of possible CGI. Interventions: Patients underwent VLS along with the standard workup consisting of evaluation of symptoms, GI tonometry, and abdominal CT or magnetic resonance angiography. Main Outcome Measurements: VLS measurements and the diagnosis of CGI as established with the standard workup. Results: In 16 months, 121 patients were included: 80 in a training data set and 41 patients in a validation data set. CGI was diagnosed in 89 patients (74%). VLS cutoff values were determined based on the diagnosis of CGI and applied in the validation data set, and the results were compared with the criterion standard, resulting in a sensitivity and specificity of VLS of 90% and 60%, respectively. Repeated VLS measurements showed improvement in 80% of CGI patients after successful treatment. Limitations: Single-center study; only 43% of patients had repeated VLS measurements after treatment. Conclusions: VLS during upper endoscopy is a promising easy-to-perform and minimally invasive technique to detect mucosal hypoxemia in patients clinically suspected of having CGI, showing excellent correlation with the established ischemia workup.

Mutations in SMAD3 cause a syndromic form of aortic aneurysms and dissections with early-onset osteoarthritis (Article)

2011-02-01T00:00:00Z

Thoracic aortic aneurysms and dissections are a main feature of connective tissue disorders, such as Marfan syndrome and Loeys-Dietz syndrome. We delineated a new syndrome presenting with aneurysms, dissections and tortuosity throughout the arterial tree in association with mild craniofacial features and skeletal and cutaneous anomalies. In contrast with other aneurysm syndromes, most of these affected individuals presented with early-onset osteoarthritis. We mapped the genetic locus to chromosome 15q22.2-24.2 and show that the disease is caused by mutations in SMAD3. This gene encodes a member of the TGF-β pathway that is essential for TGF-β signal transmission. SMAD3 mutations lead to increased aortic expression of several key players in the TGF-β pathway, including SMAD3. Molecular diagnosis will allow early and reliable identification of cases and relatives at risk for major cardiovascular complications. Our findings endorse the TGF-β pathway as the primary pharmacological target for the development of new treatments for aortic aneurysms and osteoarthritis.

Histological changes in patients with chronic upper gastrointestinal ischaemia (Article)

2010-10-01T00:00:00Z

Aims: Diagnosing chronic upper gastrointestinal ischaemia (CUGI) remains a challenge in clinical practice. Histological examination of biopsy material currently plays no role in the diagnosis of transient CUGI, as little is known about gastrointestinal histology in these patients. The aim of this study was to investigate upper gastrointestinal histology in patients with well-defined CUGI.Methods and results: Consecutive patients suspected of CUGI were included prospectively and underwent a diagnostic work-up existing of upper endoscopy, gastrointestinal tonometry and computed tomography (CT) or magnetic resonance (MR) angiography. Results were discussed in a multidisciplinary team and a consensus diagnosis was made. Endoscopic biopsy samples were taken from the descending duodenum, gastric antrum and corpus, and scored using the Sydney, Vienna, Chiu, Marsh and Operative Link for Gastritis Assessment (OLGA) classifications. Gastropathy was scored present or absent. Seventy-nine patients were analysed in 8 months. CUGI was diagnosed in 41 patients (52%): 36 males, mean age 60 (17-86) years. Prevalence of gastropathy was significantly higher in patients with ischaemia (P = 0.025). No other differences were found between patients with and without ischaemia.Conclusions: Histological examination of biopsy samples plays no definitive role in diagnosing CUGI, but the presence of histological signs of reactive gastropathy can be used to support the clinical diagnosis of ischaemia.

Stereotactic body radiotherapy using real-time tumor tracking in octogenarians with non-small cell lung cancer (Article)

2010-09-01T00:00:00Z

As the incidence of stage I non-small cell lung cancer (NSCLC) increases among octogenarians and only selected patients are surgical candidates, an alternative treatment is necessary. This manuscript evaluates the overall survival, local tumor control rate, and treatment-related toxicity after stereotactic body radiotherapy (SBRT) in 38 octogenarians with stage I NSCLC. Treatment consisted of 45. Gy (n= 4) or 60. Gy (n= 25) in 3 fractions for patients with peripheral tumors. A risk adaptive schedule of 45-60. Gy in 3-6 fractions was used for central (n= 7) or large peripheral tumors (n= 2).An overall survival rate of 65% at 1 year and 44% at 2 years was achieved in octogenarians after SBRT. The local tumor control rate was excellent (100% at 2 years) and no grade 4 or 5 treatment-related toxicity occurred. Despite the high incidence of comorbidity in these octogenarians (Charlson score ≥5 in 16% of patients), an approach that merely provides supportive care cannot always be justified. SBRT offers octogenarians with stage I NSCLC a good treatment alternative.

Standardized definitions and clinical endpoints in carotid artery and supra-aortic trunk revascularization trials (Article)

2010-09-01T00:00:00Z

Background: Endovascular therapy has emerged as a promising alternative to open surgery for stroke prevention in patients with obstructive disease of the supra-aortic arteries. Although most previous studies have used similar safety and efficacy endpoints, differences in definitions, timing of assessments, and standards of reporting have hampered direct comparisons across various trials. Methods and results: The DEFINE group, an informal collaboration of multidisciplinary physicians, involved in the therapy of patients with obstructive disease of the supra-aortic arteries in Europe and the United States reviewed the current literature and, after extensive correspondence and meetings, proposed the definitions outlined in the present manuscript. Three meetings including all authors of the manuscript, along with representatives of the United States Food and Drug Administration (FDA) and commercial device manufacturers were held in Barcelona, Spain, in May 2008, in Munich, Germany, in July 2008, and in New York in November 2008. The proposed definitions encompass baseline clinical and anatomic characteristics, clinical and radiologic outcomes, complications, standards of reporting, and timing of assessment. Conclusions: Considering the broad consensus between the multidisciplinary scientific members and the regulatory authorities, the proposed definitions are expected to find adoption in future clinical investigations. These definitions can be applied to both endovascular and open surgery trials and will allow reliable comparisons between these two revascularization methods.

A giant antral ulceration evoked by a rare cause of single-vessel chronic GI ischemia (Article)

2010-07-01T00:00:00Z

Predicting Patient-Specific Expansion of Abdominal Aortic Aneurysms (Article)

2010-07-01T00:00:00Z

Objective: Local anatomy and the patient's risk profile independently affect the expansion rate of an abdominal aortic aneurysm. We describe a hybrid method that combines finite element modelling and statistical methods to predict patient-specific aneurysm expansion. Methods: The 3-D geometry of the aneurysm was imaged with computed tomography. We used finite element methods to calculate wall stress and aneurysm expansion. Expansion rate was adjusted by risk factors obtained from a database of 80 patients. Aneurysm diameters predicted with and without the risk profiles were compared with diameters measured with ultrasound for 11 patients. Results: For this specific group of patients, local anatomy contributed 62% and the risk profile 38% to the aneurysmal expansion rate. Predictions with risk profiles resulted in smaller root mean square errors than predictions without risk profiles (2.9 vs. 4.0 mm, p < 0.01). Conclusions: This hybrid approach predicted aneurysmal expansion for a period of 30 months with high accuracy.

Quality of Life After Stereotactic Radiotherapy for Stage I Non-Small-Cell Lung Cancer (Article)

2010-05-01T00:00:00Z

Purpose: To determine the impact of stereotactic radiotherapy on the quality of life of patients with inoperable early-stage non-small-cell lung cancer (NSCLC). Overall survival, local tumor control, and toxicity were also evaluated in this prospective study. Methods and Materials: From January 2006 to February 2008, quality of life, overall survival, and local tumor control were assessed in 39 patients with pathologically confirmed T1 to 2N0M0 NSCLC. These patients were treated with stereotactic radiotherapy. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ) C30 and the QLQ LC13 lung cancer-specific questionnaire were used to investigate changes in quality of life. Assessments were done before treatment, at 3 weeks, and at 2, 4, 6, 9, and 12 months after treatment, until death or progressive disease. Toxicity was evaluated using common terminology criteria for adverse events version 3.0. Results: Emotional functioning improved significantly after treatment. Other function scores and QLQ C30 and QLQ LC13 lung symptoms (such as dyspnea and coughing) showed no significant changes. The overall 2-year survival rate was 62%. After a median follow-up of 17 months, 1 patient had a local recurrence (3%). No grade 4 or 5 treatment-related toxicity occurred. Grade 3 toxicity consisted of thoracic pain, which occurred in 1 patient within 4 months of treatment, while it occurred thereafter in 2 patients. Conclusions: Quality of life was maintained, and emotional functioning improved significantly after stereotactic radiotherapy for stage I NSCLC, while survival was acceptable, local tumor control was high, and toxicity was low.

The clinical feasibility of deep hyperthermia treatment in the head and neck (Article)

2010-04-06T00:00:00Z

To apply high-quality hyperthermia treatment to tumours at deep locations in the head and neck (H&N), we have designed and built a site-specific phased-array applicator. Earlier, we demonstrated its features in parameter studies, validated those by phantom measurements and clinically introduced the system. In this paper we will critically reviewour first clinical experiences and demonstrate the pivotal role of hyperthermia treatment planning (HTP). Three representative patient cases (thyroid, oropharynx and nasal cavity) are selected and discussed. Treatment planning, the treatment, interstitially measured temperatures and their interrelation are analysed from a physics point of view. Treatments lasting 1 h were feasible and well tolerated and no acute treatment-related toxicity has been observed. Maximum temperatures measured are in the range of those obtained during deep hyperthermia treatments in the pelvic region but mean temperatures are still to be improved. Further, we found that simulated power absorption correlated well with measured temperatures illustrating the validity of our treatment approach of using energy profile optimizations to arrive at higher temperatures. This is the first data proving that focussed heating of tumours in the H&N is feasible. Further, HTP proved a valuable tool in treatment optimization. Items to improve are (1) the transfer of HTP settings into the clinic and (2) the registration of the thermal dose, i.e. dosimetry.

A comparative study of myocardial injury during conventional and endovascular aortic aneurysm repair: Measurement of cardiac troponin T and plasma cytokine release (Article)

2010-03-01T00:00:00Z

Background: Major aortic surgery results in significant haemodynamic and oxidative stress to the myocardium. Cytokine release is a major factor in causing cardiac injury during aortic surgery. Endovascular aortic aneurysm repair (EVAR) has the potential to reduce the severity of the ischaemia reperfusion syndrome and its systemic consequences. Aim: The aim of this study was to investigate the occurrence of myocardial injury during conventional and endovascular abdominal aortic aneurysm repair using measurement of the myocardial-specific protein, cardiac troponin T. Interleukin-6 was also measured in both groups and haemodynamic responses to surgery assessed. Methods: Nine consecutive patients undergoing conventional infra-renal aortic aneurysm surgery were compared with 13 patients who underwent EVAR. Patients were allocated on the basis of aneurysm morphology and suitability for endovascular repair. Results: Patients undergoing open repair had significantly more haemodynamic disturbance than those having endovascular repair (mean arterial pressure at 5 min following unclamping or balloon deflation: open (69.6 + 3.3 mmHg); endovascular (86 + 4.4 mmHg), P < 0.05 vs. pre-op). Troponin T levels at 48 h post-operatively were higher in patients who underwent open repair (open 0.164 + 0.1 ng/ml; endovascular 0.008 + 0.0005 ng/ml, P < 0.04). Significantly more patients in the open repair group had troponin T levels > 0.1 ng/l when compared with the endovascular group (P < 0.01, χ 2 test) Conclusion: Endovascular aortic surgery produces significantly less myocardial injury than the open technique of aortic aneurysm repair.

The clinical feasibility of deep hyperthermia treatment in the head and neck (Article)

2010-01-01T00:00:00Z

Legal aspects of cross-border teleradiology (Article)

2010-01-01T00:00:00Z

The growth of cross-border teleradiology has created legal challenges that are insufficiently addressed by nation health laws. New legislation is currently under development at the European level. This article will look at the details of the existing and proposed legislation and the still unsettled issues and will discuss the implications for international teleradiology.

Long-term patient satisfaction after percutaneous treatment of peripheral vascular malformations (Article)

2009-06-01T00:00:00Z

Purpose: To determine long-term patient satisfaction for percutaneous treatment by using sclerosing agents (sclerotherapy) and/or arterial embolization for peripherally located vascular malformations (VMs). This treatment has been described as successful; however, there is a relative paucity of published long-term results. Materials and Methods: This retrospective study was institutional review board approved; 107 patients treated for symptomatic VM were evaluated. After informed consent was obtained, 66 patients were sent a questionnaire regarding treatment effectiveness and patient satisfaction. Patient files and imaging data were retrieved to obtain information regarding the VMs and VM treatment. Kaplan-Meier survival curves were constructed to analyze clinical success rates over time. Results: The most frequent reasons for patients to seek treatment were pain (89%, n = 59) and swelling (91%, n = 60). The majority of VMs were the low-flow venous type (83%, n = 55). Three months after treatment, clinical success was reported for 58% (n = 38) of patients and clinical failure was reported for 42% (n = 28). At 1-, 2-, 3-, 4-, and 5-year follow-up, clinical success was 49%, 49%, 42%, 42%, and 42%, respectively. Twenty-seven (40%) patients experienced complications, 12 of which required additional treatment. In all, 35 (53%) patients reported being satisfied with their treatment. Patient satisfaction was closely correlated with clinically successful long-term outcome of treatment. Conclusion: Initial partial or complete relief of VM complaints after percutaneous treatment is expected in 58% of patients, irrespective of VM size or classification. These results were durable over a 5-year follow-up period.

Assessment of biventricular functional reserve and NT-proBNP levels in patients with RV volume overload after repair of tetralogy of Fallot at young age (Article)

2009-04-17T00:00:00Z

Purpose: To assess biventricular functional reserve (FR), NT-proBNP levels and exercise performance, in relation to right ventricular volume in patients with pulmonary regurgitation (PR) after repair of tetralogy of Fallot (TOF) at young age. Methods: In 53 TOF patients (maximum age at repair 2.0 years, interval since repair 15 (5) years) without residual lesions except PR, biventricular FR (derived from magnetic resonance imaging with dobutamine stress), NT-proBNP levels, maximal workload, and peak oxygen uptake were assessed. Results: Mean right ventricular end-diastolic volume was 140(38) ml/m2. Median pulmonary regurgitant fraction was 37% (range 0-57%). Biventricular systolic stress response was normal: mean (SD) ESV decreased (ΔRVESV - 17(8) ml/m2, ΔLVESV - 11(5)), SV increased (ΔRVSV + 12(9) ml/m2, ΔLVSV + 9(6)), FR was positive in all (RV-FR + 11(5)%, LV-FR + 13(6)). No serious adverse effects to dobutamine were encountered. NT-proBNP was increased in 2 patients. Median level was 10 pmol/L (range 2-42). NT-proBNP correlated with PR-percentage but not with right ventricular size. High-risk levels of NT-proBNP indicated a smaller RV-FR and a smaller decrease of biventricular ESV. Mean (SEM) VO2maxwas 96(3)%, mean Workloadmax89(2)% of predicted. Conclusion: At mid to long term follow-up overall NT-proBNP levels are normal and biventricular functional reserve and exercise tolerance are well preserved in TOF repaired at young age, irrespective of RV volume. This questions the validity of isolated PR or RV volume criteria for pulmonary valve replacement in this group. Low-dose dobutamine stress testing is well tolerated and may be a useful additional tool for clinical decision making.

Intermittent claudication: Clinical effectiveness of endovascular revascularization versus supervised hospital-based exercise training-randomized controlled trial (Article)

2009-02-01T00:00:00Z

Purpose: To compare clinical success, functional capacity, and quality of life during 12 months after revascularization or supervised exercise training in patients with intermittent claudication. Materials and Methods: This study had institutional review board approval, and all patients gave written informed consent. Between September 2002 and September 2005, 151 consecutive patients who presented with symptoms of intermittent claudication were randomly assigned to undergo either endovascular revascularization (angioplasty-first approach) (n = 76) or hospital-based supervised exercise (n = 75). The outcome measures were clinical success, functional capacity, and quality of life after 6 and 12 months. Clinical success was defined as improvement in at least one category in the Rutherford scale above the pretreatment level. Significance of differences between the groups was assessed with the unpaired τ test, x2 test, or Mann-Whitney U test. To adjust outcomes for imbalances of baseline values, multi-variable regression analysis was performed. Results: Immediately after the start of treatment, patients who underwent revascularization improved more than patients who performed exercise in terms of clinical success (adjusted odds ratio [OR], 39; 99% confidence interval [CI]: 11, 131; P <.001), but this advantage was lost after 6 (adjusted OR, 0.9; 99% CI: 0.3, 2.3; P = .70) and 12 (adjusted OR, 1.1; 99% CI: 0.5, 2.8; P = .73) months. After revascularization, fewer patients showed signs of ipsilateral symptoms at 6 months compared with patients in the exercise group (adjusted OR, 0.4; 99% CI: 0.2, 0.9; P <.001), but no significant differences were demonstrated at 12 months. After both treatments, functional capacity and quality of life scores increased after 6 and 12 months, but no significant differences between the groups were demonstrated. Conclusion: After 6 and 12 months, patients with intermittent claudication benefited equally from either endovascular revascularization or supervised exercise. Improvement was, however, more immediate after revascularization.

Cost-effectiveness of endovascular revascularization compared to supervised hospital-based exercise training in patients with intermittent claudication: A randomized controlled trial (Article)

2008-12-01T00:00:00Z

Background: The optimal first-line treatment for intermittent claudication is currently unclear. Objective: To compare the cost-effectiveness of endovascular revascularization vs supervised hospital-based exercise in patients with intermittent claudication during a 12-month follow-up period. Design: Randomized controlled trial with patient recruitment between September 2002-September 2006 and a 12-month follow-up per patient. Setting: A large community hospital. Participants: Patients with symptoms of intermittent claudication due to an iliac or femoro-popliteal arterial lesion (293) who fulfilled the inclusion criteria (151) were recruited. Excluded were, for example, patients with lesions unsuitable for revascularization (iliac or femoropopliteal TASC-type D and some TASC type-B/C. Intervention: Participants were randomly assigned to endovascular revascularization (76 patients) or supervised hospital-based exercise (75 patients). Measurements: Mean improvement of health-related quality-of-life and functional capacity over a 12-month period, cumulative 12-month costs, and incremental costs per quality-adjusted life year (QALY) were assessed from the societal perspective. Results: In the endovascular revascularization group, 73% (55 patients) had iliac disease vs 27% (20 patients) femoral disease. Stents were used in 46/71 iliac lesions (34 patients) and in 20/40 femoral lesions (16 patients). In the supervised hospital-based exercise group, 68% (51 patients) had iliac disease vs 32% (24 patients) with femoral disease. There was a non-significant difference in the adjusted 6- and 12-month EuroQol, rating scale, and SF36-physical functioning values between the treatment groups. The gain in total mean QALYs accumulated during 12 months, adjusted for baseline values, was not statistically different between the groups (mean difference revascularization versus exercise 0.01; 99% CI -0.05, 0.07; P = .73). The total mean cumulative costs per patient was significantly higher in the revascularization group (mean difference €2318; 99% CI €2130, € 2506; P < .001) and the incremental cost per QALY was 231 800 €/QALY adjusted for the baseline variables. One-way sensitivity analysis demonstrated improved effectiveness after revascularization (mean difference 0.03; CI 0.02, 0.05; P < .001), making the incremental costs 75 208 €/QALY. Conclusion: In conclusion, there was no significant difference in effectiveness between endovascular revascularization compared to supervised hospital-based exercise during 12-months follow-up, any gains with endovascular revascularization found were non-significant, and endovascular revascularization costs more than the generally accepted threshold willingness-to-pay value, which favors exercise.

Pulmonary artery size and function after fontan operation at a young age (Article)

2008-11-01T00:00:00Z

Purpose: To assess pulmonary artery (PA) size, flow variables, and wall shear stress (WSS) in patients after Fontan operation at a young age. Materials and Methods: Flow in the branch PA was obtained with phase contrast velocity-encoded cardiovascular magnetic resonance imaging in 14 patients before and after low-dose dobutamine stress (7.5 μg/kg/min) and in 17 healthy controls at rest. Results: At rest, stroke index, total flow, average, and peak flow rate were all statistically significantly lower in patients than in controls (P < 0.001). With stress-testing, all variables increased in patients (P < 0.001), apart from stroke index, which did not change. At rest, branch PA area did not differ between patients and controls. Distensibility was lower in patients than in controls (P < 0.001). With stress-testing, area and distensibility did not change. At rest, WSS was lower in patients than in controls (P < 0.001). WSS increased with stress-testing (P < 0.001), but not to the same levels as during resting conditions of the control group. Conclusion: PA size is normal long-term after Fontan operation at a young age. Flow variables, distensibility, and WSS are significantly lower compared to healthy controls, and do not show adequate reactions with stress-testing, which is suggestive of pulmonary artery endothelial and/or vascular dysfunction.

Clinical Endpoints in Peripheral Endovascular Revascularization Trials: a Case for Standardized Definitions (Article)

2008-10-01T00:00:00Z

Background: Endovascular therapy is a rapidly expanding option for the treatment of patients with peripheral arterial disease (PAD), leading to a myriad of published studies reporting on various revascularization strategies. However, these reports are often difficult to interpret and compare because they do not utilize uniform clinical endpoint definitions. Moreover, few of these studies describe clinical outcomes from a patients' perspective. Methods and results: The DEFINE Group is a collaborative effort of an ad-hoc multidisciplinary team from various specialties involved in peripheral arterial disease therapy in Europe and the United States. DEFINE's goal was to arrive at a broad based consensus for baseline and endpoint definitions in peripheral endovascular revascularization trials for chronic lower limb ischemia. In this project, which started in 2006, the individual team members reviewed the existing pertinent literature. Following this, a series of telephone conferences and face-to-face meetings were held to agree upon definitions. Input was also obtained from regulatory (United States Food and Drug Administration) and industry (device manufacturers with an interest in peripheral endovascular revascularization) stakeholders, respectively. The efforts resulted in the current document containing proposed baseline and endpoint definitions in chronic lower limb PAD. Although the consensus has inevitably included certain arbitrary choices and compromises, adherence to these proposed standard definitions would provide consistency across future trials, thereby facilitating evaluation of clinical effectiveness and safety of various endovascular revascularization techniques. Conclusion: This current document is based on a broad based consensus involving relevant stakeholders from the medical community, industry and regulatory bodies. It is proposed that the consensus document may have value for study design of future clinical trials in chronic lower limb ischemia as well as for regulatory purposes.

Endovascular coils as lung tumour markers in real-time tumour tracking stereotactic radiotherapy: Preliminary results (Article)

2008-08-01T00:00:00Z

To evaluate the use of endovascular coils as markers for respiratory motion correction during high-dose stereotactic radiotherapy with the CyberKnife, an image-guided linear accelerator mounted on a robotic arm. Endovascular platinum embolisation coils were used to mark intrapulmonary lesions. The coils were placed in subsegmental pulmonary artery branches in close proximity to the target tumour. This procedure was attempted in 25 patients who were considered unsuitable candidates for standard transthoracic percutaneous insertion. Vascular coils (n=87) were succesfully inserted in 23 of 25 patients. Only minor complications were observed: haemoptysis during the procedure (one patient), development of pleural pain and fever on the day of procedure (one patient), and development of small infiltrative changes distal to the vascular coil (five patients). Fifty-seven coils (66% of total inserted number) could be used as tumour markers for delivery of biologically highly effective radiation doses with automated tracking during CyberKnife radiotherapy. Endovascular markers are safe and allow high-dose radiotherapy of lung tumours with CyberKnife, also in patients who are unsuitable candidates for standard transthoracic percutaneous marker insertion.

Cardiac status after childhood growth hormone treatment of Turner syndrome (Article)

2008-07-01T00:00:00Z

Context: In Turner syndrome (TS), GH treatment is well established. Data on cardiac status after discontinuation of treatment are scarce. This study aimed to assess biventricular size and function in TS at least 6 months after discontinuation of GH treatment. Methods: TS patients and healthy women prospectively underwent cardiac magnetic resonance imaging. Ventricular two-dimensional tomographic cine data were acquired to obtain biventricular volume, mass, and ejection fraction. Atrioventricular valve flow measurements were performed using a two-dimensional flow-sensitized sequence. Flow velocity curves were calculated and indices of biventricular diastolic filling were derived. Results: Thirty-one patients [mean (SD) age 20 (2) yr, body surface area 1.75 (0.15)m2, 5 (2) yr after GH discontinuation] and 23 normal control women [age 21 (2) yr, body surface area 1.80 (0.13)m2] were included. Compared with controls, patients had smaller mean end-diastolic volumes [right ventricle (RV), 84 (11) ml/m2vs. 79 (10), P = 0.02; left ventricle (LV), 81 (10) vs. 72 (9), P < 0.001], end-systolic volumes [RV 38 (7) ml/m2vs. 36 (6), P = 0.04; LV 34 (5) vs. 29 (4), P < 0.001], and stroke volumes [RV 46 (6) ml/m2vs. 43 (6), P = 0.03; LV, 47 (7) vs. 44 (4), P = 0.02]. Patients had a higher meanheart rate [79 (13) beats/min vs. 71 (10), P < 0.05]. Biventricular ejection fraction, mass, cardiac output, and diastolic filling pattern were comparable. Conclusion: After discontinuation of GH treatment TS patients showed no myocardial hypertrophy and well-preserved biventricular function. Ventricular volumes were smaller in Turner patients, compared with controls, whereas mean heart rate was higher. These last observations may be part of the natural development in TS and not linked to GH treatment, which at this point we consider safe. Copyright

A numerical model to predict abdominal aortic aneurysm expansion based on local wall stress and stiffness (Article)

2008-06-03T00:00:00Z

Aneurysms of the abdominal aorta enlarge until rupture occurs. We assume that this is the result of remodelling to restore wall stress. We developed a numerical model to predict aneurysm expansion based on this assumption. In addition, we obtained aneurysm geometry of 11 patients from computed tomography angiographic images to obtain patient specific calculations. The assumption of a wall stress related expansion indeed resulted in a series of local expansions, adjusting global geometry in an exponential fashion similar as in patients. Furthermore, it revealed that location of peak wall stress changed over time. The assumptions of this model are discussed in detail in this manuscript, and the implications are related to literature findings.

Usefulness of Cardiac Magnetic Resonance Imaging Combined With Low-Dose Dobutamine Stress to Detect an Abnormal Ventricular Stress Response in Children and Young Adults After Fontan Operation at Young Age (Article)

2008-06-01T00:00:00Z

After Fontan operation, patients are limited in increasing cardiac output and in exercise capacity. This has been related to impaired preload or other factors leading to decreased global ventricular performance with stress. To study these factors, the stress responses of functionally univentricular hearts were assessed at rest and during low-dose dobutamine stress using cardiovascular magnetic resonance imaging. Thirty-two patients after Fontan completion at young age were included (27 with total cavopulmonary connection, 5 with atriopulmonary connection; mean age 13.3 years, range 7.5 to 22.2; 23 male patients; median follow-up after Fontan operation 8.1 years, range 5.2 to 17.8). A multiphase short-axis stack of 10 to 12 contiguous slices of the systemic ventricle was obtained at rest and during low-dose dobutamine stress cardiovascular magnetic resonance imaging (maximum 7.5 μg/kg/min). With stress-testing, heart rate, ejection fraction, and cardiac index increased adequately (p <0.001). There was an abnormal decrease in end-diastolic volume and an adequate decrease in end-systolic volume (p <0.001). Stroke volume did not change with stress testing (p = 0.15). At rest, dominant left ventricles had higher ejection fractions than dominant right ventricles (p = 0.01), but this difference disappeared with stress testing. In conclusion, a functionally univentricular heart after Fontan completion at young age has an adequate increase in ejection fraction with β-adrenergic stimulation. However, as a result of impaired preload with stress, cardiac output can be increased only by increasing heart rate.

Multicenter randomized controlled trial of the costs and effects of noninvasive diagnostic imaging in patients with peripheral arterial disease: The DIPAD trial (Article)

2008-05-01T00:00:00Z

OBJECTIVE. The purpose of our study was to compare the costs and effects of three noninvasive imaging tests as the initial imaging test in the diagnostic workup of patients with peripheral arterial disease. MATERIALS AND METHODS. Of 984 patients assessed for eligibility, 514 patients with peripheral arterial disease were randomized to MR angiography (MRA) or duplex sonography in three hospitals and to MRA or CT angiography (CTA) in one hospital. The outcome measures included the clinical utility, functional patient outcomes, quality of life, and actual diagnostic and therapeutic costs related to the initial imaging test during 6 months of follow-up. RESULTS. With adjustment for potentially predictive baseline variables, the learning curve, and hospital setting, a significantly higher confidence and less additional imaging were found for MRA and CTA compared with duplex sonography. No statistically significant differences were found in improvement in functional patient outcomes and quality of life among the groups. The total costs were significantly higher for MRA and duplex sonography than for CTA. CONCLUSION. The results suggest that both CTA and MRA are clinically more useful than duplex sonography and that CTA leads to cost savings compared with both MRA and duplex sonography in the initial imaging evaluation of peripheral arterial disease.

Drug-eluting stents in renal artery stenosis (Article)

2008-04-01T00:00:00Z

Because of higher acute and long-term success rates compared with balloon angioplasty alone, percutaneous stent implantation has become an accepted therapy for the treatment of atherosclerotic renal artery stenosis. Restenosis rates after successful renal stent placement vary from 6 up to 40%, depending on the definition of restenosis, the diameter of the treated vessel segment and comorbidities. The safety and efficacy of drug-eluting stents for the treatment of renal-artery stenosis is poorly defined. The recently published GREAT study is the only prospective study, comparing bare-metal and sirolimus-coated low profile stent systems in renal artery stenosis, showing a relative risk reduction of angiographic binary in-stent restenosis by 50%. This is an opinion paper on indications, current treatment options and restenosis rates following renal artery stenting and the potential use of drug-eluting stents for this indication.

Changes during exercise of ECG intervals related to increased risk for ventricular arrhythmia in repaired tetralogy of Fallot and their relationship to right ventricular size and function (Article)

2008-03-14T00:00:00Z

Purpose: Our study aimed to assess pro-arrhythmogenic electrocardiographic changes during maximal physical exercise in patients operated for Tetralogy of Fallot (TOF). Methods: TOF patients prospectively underwent: 1) bicycle ergometry, 2) cardiac MRI, and 3) 24-hour Holter. ECG data was analyzed at rest, at 60% of peak exercise and at peak exercise. R-R duration, QRS-, QT- and JT-duration and dispersions were assessed. Changes of ECG parameters during exercise were calculated and correlated to RV volume, RVEF, RV wall-mass, PR-percentage and VO2max. Exercise ECG data from healthy controls were used as reference. Results: Thirty-one patients (mean age at repair (SD) 0.8 (0.5) years, age at study 16 (5) years) and 25 controls (age 12 (2) years) were included. With exercise mean QTc and JTc dispersions increased in patients (p < 0.001), but not in controls. At peak exercise JTc dispersion was larger in patients (p < 0.01). QTc did not change with exercise in patients (p = 0.14) and decreased in controls (p < 0.05). At all levels of exercise mean QTc, QRS and QRS dispersion were larger in patients (all p < 0.001). Significant associations were found for; 1) a larger increase of JTc dispersion with a higher PR-percentage, a larger RV volume, a larger RV wall-mass, 2) a larger QTc increase with a larger RV volume and worse RVEF. Conclusion: During physical exercise inhomogeneity of repolarisation, known to predispose for re-entry ventricular arrhythmia, increases in repaired TOF. Larger inhomogeneity is found with more severe PR.

Long-term outcome of a covered vs. uncovered transjugular intrahepatic portosystemic shunt in Budd-Chiari syndrome (Article)

2008-02-01T00:00:00Z

Background: The clinical outcome of a covered vs. uncovered transjugular intrahepatic portosystemic shunt (TIPS) for patients with Budd-Chiari syndrome (BCS) is as yet largely unknown. Objectives: To compare patency rates of bare and polytetrafluoroethylene (PTFE)-covered stents, and to investigate clinical outcome using four prognostic indices [Child-Pugh score, Rotterdam BCS index, modified Clichy score and Model for End-Stage Liver Disease (MELD)]. Methods: Consecutive patients with BCS who had undergone TIPS between January 1994 and March 2006 were evaluated in a retrospective review in a single centre. Results: Twenty-three TIPS procedures were performed on 16 patients. The primary patency rate at 2 years was 12% using bare and 56% using covered stents (P = 0.09). We found marked clinical improvement at 3 months post-TIPS as determined by a drop in median Child-Pugh score (10-7, P = 0.04), Rotterdam BCS index (1.90-0.83, P = 0.02) and modified Clichy score (7.77-2.94, P = 0.003), but not in MELD (18.91-17.42, P =0.9). Survival at 1 and 3 years post-TIPS was 80% (95% CI: 59-100%) and 72% (95% CI: 48-96%). Four patients (25%) died and one required liver transplantation. Conclusions: A transjugular intrahepatic portosystemic shunt using PTFE-covered stents shows better patency rates than bare stents in BCS. Moreover, TIPS leads to an improvement in important prognostic indicators for the survival of patients with BCS. © 2008 The Authors. Journal compilation

Multi-detector row computed tomography angiography of peripheral arterial disease (Article)

2007-12-01T00:00:00Z

With the introduction of multi-detector row computed tomography (MDCT), scan speed and image quality has improved considerably. Since the longitudinal coverage is no longer a limitation, multi-detector row computed tomography angiography (MDCTA) is increasingly used to depict the peripheral arterial runoff. Hence, it is important to know the advantages and limitations of this new non-invasive alternative for the reference test, digital subtraction angiography. Optimization of the acquisition parameters and the contrast delivery is important to achieve a reliable enhancement of the entire arterial runoff in patients with peripheral arterial disease (PAD) using fast CT scanners. The purpose of this review is to discuss the different scanning and injection protocols using 4-, 16-, and 64-detector row CT scanners, to propose effective methods to evaluate and to present large data sets, to discuss its clinical value and major limitations, and to review the literature on the validity, reliability, and cost-effectiveness of multi-detector row CT in the evaluation of PAD.

Embolization with the Amplatzer Vascular Plug in TIPS patients (Article)

2007-11-01T00:00:00Z

Vessel embolization can be a valuable adjunct procedure in transjugular intrahepatic portosystemic shunt (TIPS). During the creation of a TIPS, embolization of portal vein collaterals supplying esophageal varices may lower the risk of secondary rebleeding. And after creation of a TIPS, closure of the TIPS itself may be indicated if the resulting hepatic encephalopathy severely impairs mental functioning. The Amplatzer Vascular Plug (AVP; AGA Medical, Golden Valley, MN) is well suited for embolization of large-diameter vessels and has been employed in a variety of vascular lesions including congenital arteriovenous shunts. Here we describe the use of the AVP in the context of TIPS to embolize portal vein collaterals (n = 8) or to occlude the TIPS (n = 2).

Quadrature coil design for high-resolution carotid artery imaging scores better than a dual phased-array coil design with the same volume coverage (Article)

2007-05-01T00:00:00Z

Purpose: To evaluate the ability of a custom-built coil design to provide improved signal-to-noise ratio (SNR) and less signal drop with increasing depth at the carotid artery. Materials and Methods: Phased-array surface coils can provide a high SNR to image the carotid vessel wall. However, given the required field-of-view (FOV) and penetration depth, these coils show either a fast signal drop with increasing depth or a moderate SNR at increased coil size. A quadrature surface coil (a butterfly coil in conjunction with a linear single-loop coil) was compared with a phased-array coil in phantom and human studies. Results: The phantom studies showed that the quadrature coil has better SNR over the required FOV than a standard phased-array coil (26% at 3 cm depth). Conclusion: The quadrature coil enables better image quality to be achieved.

Diastolic function in repaired tetralogy of fallot at rest and during stress: Assessment with MR imaging (Article)

2007-04-01T00:00:00Z

Purpose: To prospectively assess, with magnetic resonance (MR) imaging, right ventricular (RV) diastolic function after repair of tetralogy Fallot (TOF) at rest and during pharmacologic stress and to study relationship between main pulmonary artery end-diastolic forward flow (EDFF) (indicative of restrictive RV physiology) and clinical status. Materials and Methods: Institutional medical ethics committee approval and patient or parent informed consent were obtained. Patients with TOF corrected through the transatrial-transpulmonary approach underwent MR imaging at rest and during dobutamine stress and maximal exercise testing. Two-dimensional (2D) cine volumetric data were acquired. Flow measurements were performed with a standard 2D flow-sensitized sequence. MR imaging flow curves for tri-cuspid and pulmonary valves were combined into RV time-volume change curves, from which indexes of RV filling were derived. Patient results were compared with published data in control subjects. Student t tests, Mann-Whitney U tests, analysis of covariance, and paired and one-sample t tests were used. Results: Thirty-six patients (mean age at repair, 0.9 year ± 0.5 [standard deviation]; median age at study inclusion, 17 years, [range, 7-23 years]; 26 male and 10 female patients) were included. Abnormalities in RV filling included impaired relaxation (prolonged deceleration time, P = .002; smaller early filling fraction, P = .02) in the entire group compared with published data in healthy control subjects and signs of restriction to RV filling (smaller atrial filling fraction and higher early filling/atrial filling peak ratio, P < .05 for both) in patients with EDFF (n = 24) compared with patients without EDFF (n = 12). Stress response was abnormal in patients with EDFF, who developed impaired RV relaxation not appreciated at rest. Patients with EDFF had more severe pulmonary regurgitation (P < .05) and poorer exercise performance (P < .001). Conclusion: In patients with TOF corrected with currently widely accepted surgical strategies, pulmonary artery EDFF relates to worse clinical state at mid- to long-term follow-up. Dobutamine stress imaging may unmask abnormalities in RV diastolic filling not appreciated with rest imaging alone.

Evaluation of the AutoDimer D-dimer assay for the exclusion of pulmonary embolism [3] (Article)

2007-02-01T00:00:00Z

Clinical condition at mid-to-late follow-up after transatrial-transpulmonary repair of tetralogy of Fallot (Article)

2007-02-01T00:00:00Z

Objectives: To assess the clinical condition at mid-to-late follow-up in tetralogy of Fallot corrected by a transatrial-transpulmonary approach at a young age and to identify risk factors associated with right ventricular dilation/dysfunction and with decreased exercise tolerance. Methods: Patients with tetralogy of Fallot underwent cardiac magnetic resonance imaging, maximal bicycle ergometry, electrocardiography, Holter monitoring, and spirometry. Multivariate linear regression analyses were used to determine independent predictors for selected clinical parameters. Results: Fifty-nine patients (mean ± SD), age at repair 0.9 ± 0.5 years, interval since repair 14 ± 5 years, were included. The median pulmonary regurgitant fraction was 32% (0%-57%). Compared with published data on healthy controls, Fallot patients had significantly larger right ventricular end-diastolic and end-systolic volumes and smaller right ventricular and left ventricular ejection fractions. Maximum oxygen consumption was 97% ± 17% and maximum workload 89% ± 13% of predicted. Median QRS duration was 110 ms (82-161 ms). No important ventricular arrhythmias were found. Compared with patients without a transannular patch, patients with a patch had more pulmonary regurgitation, a larger right ventricle, worse right ventricular and left ventricular ejection fractions, but comparable exercise capacity. Multivariate regression analysis identified the following independent determinants for larger right ventricular volumes: longer interval since repair, longer QRS duration, and higher pulmonary regurgitation percentage. The following were independent determinants for smaller right ventricular ejection fraction: abnormal right ventricular outflow tract wall motion, longer interval since repair, and longer QRS duration. For smaller maximum oxygen consumption, the independent determinants were smaller right ventricular ejection fraction and longer QRS duration. Conclusions: At mid-to-late follow-up, clinical condition in tetralogy of Fallot corrected according to contemporary surgical approaches appears well preserved. However, even these patients show right ventricular dilation and dysfunction associated with impaired functional capacity. Abnormalities relate to right ventricular outflow tract motion abnormalities, longer interval since repair, longer QRS duration, and more severe pulmonary regurgitation.

Imaging peripheral arterial disease: a randomized controlled trial comparing contrast-enhanced MR angiography and multi-detector row CT angiography. (Article)

2005-09-01T00:00:00Z

PURPOSE: To prospectively evaluate clinical utility, patient outcomes, and costs of contrast material-enhanced magnetic resonance (MR) angiography compared with multi-detector row computed tomographic (CT) angiography for initial imaging in the diagnostic work-up of patients with peripheral arterial disease. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. Patients referred for diagnostic imaging work-up to evaluate the feasibility of a revascularization procedure were randomly assigned to undergo either MR angiography or CT angiography. Clinical utility was assessed with therapeutic confidence (scale of 0-10) at initial imaging and with the need for additional imaging. Patient outcomes included ankle-brachial index, maximum walking distance, change in clinical status, and health-related quality of life. Actual diagnostic and therapeutic costs were calculated from the hospital perspective. Differences between group means were calculated with unpaired t tests and 95% confidence intervals. RESULTS: A total of 157 consecutive patients with peripheral arterial disease were prospectively randomized to undergo MR angiography (51 men, 27 women; mean age, 63 years) or CT angiography (50 men, 29 women; mean age, 64 years). For one of the 78 patients in the MR group, no data were available. Mean confidence for MR angiography (7.7) was slightly lower than that for CT angiography (8.0, P = .8). During 6 months of follow-up, 13 patients in the MR group compared with 10 patients in the CT group underwent additional vascular imaging (P = .5). Although not statistically significant, there was a consistent trend of less improvement in the MR group across all patient outcomes. The average cost for diagnostic imaging was 359 ($438) higher in the MR group than in the CT group (95% confidence interval: 209, 511 [$255, $623]; P < .001). Therapeutic costs were higher in the MR group, but the difference was not significant. CONCLUSION: The results suggest that CT angiography has some advantages over MR angiography in the initial evaluation of peripheral arterial disease.

Peripheral arterial disease: therapeutic confidence of CT versus digital subtraction angiography and effects on additional imaging recommendations. (Article)

2004-11-01T00:00:00Z

PURPOSE: To compare multi-detector row computed tomographic (CT) angiography and digital subtraction angiography (DSA) prior to revascularization in patients with symptomatic peripheral arterial disease for the purpose of assessing recommendations for additional imaging and physician confidence ratings for chosen therapy. MATERIALS AND METHODS: In a randomized controlled trial, 73 patients were assigned to CT angiography, and 72 were assigned to DSA. Physician confidence in the treatment decision was measured as a continuous outcome on a scale of 0-10 (uncertain to certain) and as a dichotomous outcome (further imaging recommended, yes or no). Mean confidence scores and additional imaging recommendations were compared between CT and DSA groups in an intention-to-diagnose-and-treat analysis. To detect trends in confidence, confidence scores were plotted over time, and multiple linear regression analysis was performed. To detect trends in additional imaging recommendations, logistic regression analysis was used. Data from eligible nonrandomized patients were analyzed separately. RESULTS: No statistically significant difference in baseline characteristics between randomized groups was found. CT had a lower confidence score than did DSA (7.2 vs 8.2, P < .001). Further imaging was recommended more often after CT (25 of 71 patients, 35%) than after DSA (nine of 66 patients, 14%; P = .003). Analysis of trends demonstrated increasing (but not statistically significant) confidence in CT and stable confidence in DSA. No significant difference was found in baseline characteristics between randomized and nonrandomized patients. Among nonrandomized patients, no significant difference in mean confidence score (8.2 vs 8.3, P = .26) was found between CT (n = 24) and DSA (n = 26). CONCLUSION: With CT angiography, physician confidence decreases with an associated increase in additional imaging prior to revascularization in patients with symptomatic peripheral arterial disease. Given that CT is less invasive than DSA, results suggest that CT may replace DSA in selected cases.

Verbal communication in MR environments: effect of MR system acoustic noise on speech understanding. (Article)

2004-07-01T00:00:00Z

PURPOSE: To assess the masking effect of magnetic resonance (MR)-related acoustic noise and the effect of passive hearing protection on speech understanding. MATERIALS AND METHODS: Acoustic recordings were made at 1.5 T at patient and operator (interventionalist in the MR suite) locations for relevant pulse sequences. In an audiologic laboratory, speech-to-noise ratios (STNRs) were determined, defined as the difference between the absolute sound pressure levels of MR noise and speech. The recorded noise of the MR sequences was played simultaneously with the recorded sentences at various intensities, and 15 healthy volunteers (seven women, eight men; median age, 27 years) repeated these sentences as accurately as possible. The STNR that corresponded with a 50% correct repetition was used as the measure for speech intelligibility. In addition, the effect of passive hearing protection on speech intelligibility was tested by using an earplug model. RESULTS: Overall, speech understanding was reduced more at operator than at patient location. Most problematic were fast gradient-recalled-echo train and spiral k-space sequences. As the absolute sound pressure level of these sequences was approximately 100 dB at patient location, the vocal effort needed to attain 50% intelligibility was shouting (>77 dB). At operator location, less effort was required because of the lower sound pressure levels of the MR noise. Fast spoiled gradient-recalled-echo and echo-planar imaging sequences showed relatively favorable results with raised voice at operator location and loud speaking at patient location. The use of hearing protection slightly improved STNR. CONCLUSION: At 1.5 T, the level of MR noise requires that large vocal effort is used, at the operator and especially at the patient location. Depending on the specific MR sequence used, loud speaking or shouting is needed to achieve adequate bidirectional communication with the patient. The wearing of earplugs improves speech intelligibility.

Multi-detector row CT angiography in patients with abdominal angina. (Article)

2004-01-01T00:00:00Z

Abdominal angina (AA) is an infrequently occurring syndrome characterized by postprandial abdominal pain due to reduced blood flow to organs in the territory of the celiac trunk, superior mesenteric artery (SMA), and inferior mesenteric artery. Multi-detector row computed tomographic (CT) angiography with four- or 16-row scanners has become a primary tool for the evaluation of patients with suspected steno-occlusive diseases of the abdominal vessels. In patients with suspected AA, multi-detector row CT angiography can help evaluate the presence and degree of stenosis in the celiac trunk and SMA, demonstrate the collateral circulation, and help exclude other causes of vascular obstruction. It also allows visualization of small vessels and of vessel wall abnormalities in the absence of significant stenosis. Vessels with a complex anatomic configuration can easily be visualized with proper postprocessing techniques. This modality can also be used to follow up patients who have undergone percutaneous interventional treatment. Limitations include the lack of dynamic representation of flow abnormalities and difficulty in evaluating heavily calcified vessels. Nevertheless, multi-detector row CT angiography with appropriate postprocessing techniques is highly effective for the diagnosis, evaluation, and treatment of suspected AA. Additional studies will help further evaluate the performance and applications of this modality.

Intravenous contrast material administration at 16-detector row helical CT coronary angiography: test bolus versus bolus-tracking technique. (Article)

2004-01-01T00:00:00Z

PURPOSE: To compare test bolus and bolus-tracking techniques for intravenous contrast material administration at 16-detector row computed tomographic (CT) coronary angiography. MATERIALS AND METHODS: This study had institutional review board approval, and patients gave informed consent. Thirty-eight patients (mean age, 60 years; three women) were randomized into two groups according to bolus timing technique: group 1 (20-mL test bolus with 100-mL main bolus) and group 2 (bolus tracking with 100-mL main bolus). All patients underwent electrocardiography-gated 16-detector row CT coronary angiography with 12 detectors (collimation, 0.75 mm; rotation time, 420 msec). In group 1, test bolus peak attenuation was used as a delay, while in group 2, a +100-HU threshold in ascending aorta triggered angiographic acquisition, with an additional 4-second delay for patient instruction. Attenuation was measured in the longitudinal direction throughout the examination in three main vessels: ascending aorta (region of interest [ROI] 1), descending aorta (ROI 2), and main pulmonary artery (ROI 3). Mean attenuation and slope of bolus geometry curve were calculated in each patient and ROI. Attenuation at origin of coronary arteries was measured. Student t test was used to compare results. RESULTS: Mean scan delay was 6 seconds longer in group 2 (P < .05). Average attenuation values were 306.6 HU +/- 44.0 (standard deviation) and 328.2 HU +/- 58.6 (P > .05) in ROI 1, 291.6 HU +/- 45.1 and 326.4 HU +/- 62.6 (P > .05) in ROI 2, and 354.7 HU +/- 78.0 and 305.3 HU +/- 71.4 (P < .05) in ROI 3 for groups 1 and 2, respectively. Average slope values were 5.8 and -0.8 (P < .05) in ROI 1, 7.7 and 0.7 (P < .05) in ROI 2, and -1.0 and -13.3 (P < .05) in ROI 3 for groups 1 and 2, respectively. Average attenuation values in left main, left anterior descending, and left circumflex arteries were higher in group 2 (P < .05); there were no differences (P > .05) between groups in right coronary artery. CONCLUSION: Bolus-tracking yields more homogeneous enhancement than does the test bolus technique.

A biplane angiographic study on cardiac motion of coronary artery stents: options to minimize the target volume for high-precision external beam radiotherapy of coronary artery in-stent restenosis. (Article)

2004-01-01T00:00:00Z

PURPOSE: High-precision external beam radiotherapy (EBRT) has been suggested as a potential alternative to endovascular brachytherapy for the treatment of coronary artery in-stent restenosis. The purpose of our study was to investigate and compare different options to define a smallest feasible target volume. METHODS AND MATERIALS: The cardiac motion of 17 coronary artery stents in 17 patients was studied by use of biplane conventional angiography, recorded during breath-hold. Each stent was reconstructed in three dimensions by use of biplane sets of frames covering an entire cardiac cycle. The volume traversed by the stent during the entire or part of the cardiac cycle was determined. Four options to define the stent-traversed volume (STV) as a target for high-precision EBRT were investigated. RESULTS: The mean STV during the entire cardiac cycle was 3.5 cm3; the STV represented less than 1% of the heart volume in all patients. The STV during the diastolic and systolic phase resulted in a mean reduction of 26.6% and 29.1%, respectively, compared with the STV during the entire cardiac cycle. The smallest STV, measured during a 160-ms interval within the cardiac cycle, resulted in a mean maximal reduction of 75.9% compared with the STV during the entire cardiac cycle. CONCLUSIONS: The STV during the entire cardiac cycle represents a small potential target volume for high-precision EBRT. A significant reduction of this target volume is possible in case of definition during a selected interval within the cardiac cycle.

Evaluation of patients after coronary artery bypass surgery: CT angiographic assessment of grafts and coronary arteries. (Article)

2003-12-01T00:00:00Z

PURPOSE: To evaluate the accuracy of electrocardiography (ECG)-gated multi-detector row computed tomography (CT) in enabling the detection of obstruction of both bypass grafts and coronary arteries in symptomatic patients who have undergone coronary artery bypass grafting. MATERIALS AND METHODS: ECG-gated contrast material-enhanced multi-detector row CT angiography was performed in 24 patients after bypass surgery. Two independent blinded observers evaluated all graft and coronary segments (> or =2.0-mm diameter) for occlusion and stenosis (50%-99% luminal reduction). Conventional angiography was regarded as the standard of reference. Descriptive parameters were calculated, and the results for arterial grafts, venous grafts, and coronary arteries, as well as for high and low heart rates, were compared by using a two-sided Fisher exact test. RESULTS: The following results were obtained by observers 1 and 2, respectively: Of the 60 venous graft segments, 60 (100%) and 57 (95.0%) were assessable, with an overall detection of all 17 occlusions (both observers) and three (50.0%) and five (83.3%) of six stenoses. Of 26 arterial graft segments, 19 (73.1%) and 15 (57.7%) were assessable. In the assessable segments, four of four (100%) and two of three (66.7%) stenoses and occlusions were detected, while one and two obstructions were located in nonassessable segments. Of 211 coronary segments, 146 (69.2%) and 140 (66.4%) were assessable, and detection of 50%-100% obstruction yielded a sensitivity of 89.9% (71 of 79) and 79.4% (54 of 68) and a specificity of 74.6% (50 of 67) and 72.2% (52 of 72) for each observer. Unlike the assessment of venous and arterial grafts, assessment of the coronary arteries with multi-detector row CT was significantly better in patients with low heart rates (P <.01). CONCLUSION: Multi-detector row CT allows noninvasive angiographic evaluation of both coronary arteries and bypass grafts in patients who have undergone bypass surgery. Multi-detector row CT is more effective in examining venous grafts compared with arterial grafts and diffusely diseased coronary arteries.

MR imaging: a 'One Stop Shop' Modality for Preoperative Evaluation of Potential Living Kidney-Donors (Article)

2003-01-01T00:00:00Z

At many institutions, magnetic resonance (MR) angiography is the technique of choice for assessment of the renal arteries and renal parenchyma in potential living kidney donors. The renal arteries and renal veins have a varied anatomy and may consist of one or more vessels at several levels with variable calibers and levels of branching. These findings may play an important role in the surgeon's decision about which kidney to harvest, especially if laparoscopic nephrectomy is used. A comprehensive MR imaging protocol is used at one hospital to assess the arteries, veins, parenchyma, and collecting system of the kidneys. The protocol includes T2-weighted single-shot fast spin-echo imaging, fat-saturated T2-weighted fast spin-echo imaging, three-dimensional MR angiography and MR venography, and delayed fat-saturated three-dimensional T1-weighted gradient-echo imaging. Meticulous assessment of the source images as well as images produced with various postprocessing methods, such as full maximum intensity projection, targeted maximum intensity projection, and axial and oblique reformation, allows detailed description of the vascular anatomy and its relationship to the collecting system and parenchyma to facilitate the surgeon's decision making. The findings of MR imaging are comparable with those of other imaging modalities.

Non-invasive coronary angiography with multislice spiral computed tomography: impact of heart rate. (Article)

2002-11-01T00:00:00Z

Usefulness of multislice computed tomography for detecting obstructive coronary artery disease. (Article)

2002-04-15T00:00:00Z

The latest generation of multislice spiral computed tomography (MSCT) scanners is capable of noninvasive coronary angiography. We evaluated its diagnostic accuracy to detect stenotic coronary artery disease (CAD). In 53 patients with suspected CAD, contrast-enhanced MSCT and conventional angiography were performed. The CT data were acquired within a single breathhold, and isocardiophasic slices were reconstructed by means of retrospective electrocardiographic gating. Coronary segments of ≥2 mm in diameter, measured by quantitative angiography, were evaluated. In 70% of the 358 available segments, image quality was regarded as adequate for assessment. The overall sensitivity, specificity, and positive and negative predictive values to detect ≥50% stenotic lesions in the assessable segments were 82% (42 of 51 lesions), 93% (285 of 307 nonstenotic segments), and 66% and 97%, respectively, regarding conventional quantitative angiography as the gold standard. Proximal segments were assessable in 92%, and distal segments and side branches in 71% and 50%, respectively. Including the undetected lesions in nonassessable segments, overall sensitivity decreased to 61% but remained 82% for lesions in proximal coronary segments. MSCT correctly predicted absent, single, or multiple lesions in 55% of patients. Thus, despite potentially high image quality, current MSCT protocols offer only reasonable diagnostic accuracy in an unselected patient group with a high prevalence of CAD.

Shrinkage of the distal renal artery 1 year after stent placement as evidenced with serial intravascular ultrasound (Article)

2002-01-01T00:00:00Z

The objective of this study was to determine the quantitative intravascular ultrasound (IVUS) and angiographic changes that occur during 1 year follow-up after renal artery stent placement, given that restenosis continues to be a limitation of renal artery stent placement. 38 consecutive patients with symptomatic renal artery stenosis treated with Palmaz stent placement were studied prospectively. IVUS and angiography were performed at the time of stent placement and at 1 year follow-up. At follow-up, angiographic restenosis was seen in 14% of patients. The lumen area in the stent, seen with IVUS, was significantly decreased from 24+/-5.6 mm(2) to 17+/-5.6 mm(2) (p<0.001) solely due to plaque accumulation. The distal main renal artery showed a significant decrease in lumen area owing to a significant vessel area decrease from 39+/-14.0 mm(2) to 29+/-9.3 mm(2) (p<0.001) without plaque accumulation. Angiographic analysis confirmed this reduction in luminal diameter and showed that the distal renal artery diameter at follow-up was significantly smaller than before stent placement (86+/-23.0% vs 104+/-23.9% of the contralateral renal artery diameter; p=0.003). Besides plaque accumulation in the stent, unexplained shrinkage of the distal main renal artery was evidenced with IVUS and angiography 1 year following stent placement.

Non-invasive coronary angiography with multislice spiral computed tomography: impact of heart rate (Article)

2002-01-01T00:00:00Z

OBJECTIVE: To evaluate the impact of heart rate on the diagnostic accuracy of coronary angiography by multislice spiral computed tomography (MSCT). DESIGN: Prospective observational study. PATIENTS: 78 patients who underwent both conventional and MSCT coronary angiography for suspicion of de novo coronary artery disease (n=53) or recurrent coronary artery disease after percutaneous intervention (n=25). SETTING: Tertiary referral centre. METHODS: Intravenously contrast enhanced MSCT coronary angiography was done during a single breath hold, and ECG synchronised images were reconstructed retrospectively. All coronary segments of > or = 2.0 mm without stents were evaluated by two investigators and compared with quantitative coronary angiography. Patients were classified according to the average heart rate (mean (SD)) into three equally sized groups: group 1, 55.8 (4.1) beats/min; group 2, 66.6 (2.8) beats/min; group 3, 81.7 (8.8) beats/min. RESULTS: Image quality was sufficient for analysis in 78% of the coronary segments in patients in group 1, 73% in group 2, and 54% in group 3 (p < 0.01). The sensitivity and specificity for detecting significant stenoses (> or = 50% lumen reduction) in these assessable segments were: 97% (95% confidence interval (CI) 84% to 100%) and 96% in group 1; 74% (52% to 89%) and 94% in group 2; and 67% (33% to 90%) and 94% in group 3 (p < 0.05). Accounting for all segments of > or = 2.0 mm, including lesions in non-assessable segments as false negatives, the sensitivity decreased to 82% (28/34 lesions, 95% CI 69% to 91%), 61% (14/23 lesions, 42% to 77%), and 32% (6/19 lesions, 15% to 50%), respectively (p < 0.01). CONCLUSIONS: MSCT allows reliable coronary angiography in patients with low heart rates.

Interventional MR imaging at 1.5 T: quantification of sound exposure (Article)

2002-01-01T00:00:00Z

Sound pressure levels (SPLs) during interventional magnetic resonance (MR) imaging may create an occupational hazard for the interventional radiologist (ie, the potential risk of hearing impairment). Therefore, A-weighted and linear continuous-equivalent SPLs were measured at the entrance of a 1.5-T MR imager during cardiovascular and real-time pulse sequences. The SPLs ranged from 81.5 to 99.3 dB (A-weighted scale), and frequencies were from 1 to 3 kHz. SPLs for the interventional radiologist exceeded a safe SPL of 80 dB (A-weighted scale) for all sequences; therefore, hearing protection is recommended.

A precious metal alloy for construction of MR imaging-compatible balloon-expandable vascular stents (Article)

2001-01-01T00:00:00Z

The authors developed ABI alloy, which mechanically resembles stainless steel 316. The main elements of ABI alloy are palladium and silver. Magnetic resonance (MR) images and radiographs of ABI alloy and stainless steel 316 stent models and of nitinol, tantalum, and Elgiloy stents were compared. ABI alloy showed the least MR imaging artifacts and was more radiopaque than stainless steel 316. ABI alloy has the potential to replace stainless steel 316 for construction of balloon-expandable MR imaging-compatible stents.

Interventieradiologie: weten van twee wallen (Inaugural Lecture)

2000-02-04T00:00:00Z

Intravascular ultrasound evidence for coarctation causing symptomatic renal artery stenosis (Article)

1999-01-01T00:00:00Z

BACKGROUND: A recent study of human cadaveric renal arteries revealed that renal artery narrowing could be due not only to atherosclerotic plaque compensated for by adaptive remodeling, but also to hitherto undescribed focal narrowing of an otherwise normal renal arterial wall (ie, coarctation). The present study investigated whether vessel coarctation could be identified in patients with symptomatic renal artery stenosis (RAS). METHODS AND RESULTS: Consecutive symptomatic patients with angiographically proven atherosclerotic RAS who were referred for stent placement were studied by 30-MHz intravascular ultrasound before intervention (n=18) or after predilatation (n=18). Analysis included assessment of the media-bounded area and plaque area (PLA) at the most stenotic site and at a distal reference site (most distal cross-section in the main renal artery with normal appearance). Coarctation was considered present whenever the target/reference media-bounded area was