Moelker, A.

The effect of LDLR-negative genotype on CT coronary atherosclerosis in asymptomatic statin treated patients with heterozygous familial hypercholesterolemia (Article)

2013-04-01T00:00:00Z

Objective: To evaluate the influence of LDL receptor (LDLR) -negative mutational status on CT coronary atherosclerosis in asymptomatic statin treated patients with heterozygous familial hypercholesterolemia (FH). Methods: Coronary CT angiography (CCTA) was performed in 145 FH patients (93 men; mean age 52 ± 8) screened for LDLR and apolipoprotein B (APOB) mutations. The extent of coronary plaque was compared between two groups: 1) 59 patients (41%) heterozygous for LDLR-negative mutations (LDLR-negative) and 2) 86 patients (59%) with reduced or normal LDLR function (LDLR-positive) consisting of 32 LDLR-defective mutations, 8 APOB mutations and 46 patients in whom no mutation could be identified.The diseased segments score (DSS) was the primary study endpoint defined as the number of coronary artery segments (0-17) with >20% luminal diameter narrowing. We compared the DSS between LDLR-negative and LDLR-positive patients. Within the LDLR-positive group a secondary analysis was performed between identified (LDLR-defective, APOB) and unidentified mutational status. Results: The median DSS was higher in LDLR-negative than in LDLR-positive patients (4 (1-7) and 2 (0-5); P = 0.017). After adjustment for risk factors, LDLR-negative mutational status remained an independent predictor of the DSS (B = 1.09; P = 0.047). The DSS in the LDLR-positive group was similar for patients with identified and patients with unidentified mutational status. Conclusion: In asymptomatic statin treated patients with a clinical diagnosis of FH, LDLR-negative mutational status is associated with a higher extent of subclinical CT coronary atherosclerosis.

Ascending aorta dilatation in patients with bicuspid aortic valve stenosis: a prospective CMR study (Article)

2012-09-26T00:00:00Z

Background: The aim of this study was to evaluate the natural progression of aortic dilatation and its association with aortic valve stenosis (AoS) in patients with bicuspid aortic valve (BAV). Methods: Prospective study of aorta dilatation in patients with BAV and AoS using cardiac magnetic resonance (CMR). Aortic root, ascending aorta, aortic peak velocity, left ventricular systolic and diastolic function and mass were assessed at baseline and at 3-year follow-up. Results: Of the 33 enrolled patients, 5 needed surgery, while 28 patients (17 male; mean age: 31 ± 8 years) completed the study. Aortic diameters significantly increased at the aortic annulus, sinus of Valsalva and tubular ascending aorta levels (P < 0.050). The number of patients with dilated tubular ascending aortas increased from 32 % to 43 %. No significant increase in sino-tubular junction diameter was observed. Aortic peak velocity, ejection fraction and myocardial mass significantly increased while the early/late filling ratio significantly decreased at follow-up (P < 0.050). The progression rate of the ascending aorta diameter correlated weakly with the aortic peak velocity at baseline (R2= 0.16, P = 0.040). Conclusion: BAV patients with AoS showed a progressive increase of aortic diameters with maximal expression at the level of the tubular ascending aorta. The progression of aortic dilatation correlated weakly with the severity of AoS. Key Points: • Bicuspid aortic valve (BAV) is the most common congenital heart defect. • BAV patients have an increased risk of developing aortic valve stenosis (AoS). • BAV patients have an increased risk of developing thoracic aorta dilatation. • The severity of aortic stenosis is correlated to the progression of aortic dilatation. • Cardiac magnetic resonance can rapidly assess patients with a bicuspid aortic valve.

Phenotypic spectrum of the SMAD3-related aneurysms-osteoarthritis syndrome (Article)

2012-01-01T00:00:00Z

Background: Aneurysmseosteoarthritis syndrome (AOS) is a new autosomal dominant syndromic form of thoracic aortic aneurysms and dissections characterised by the presence of arterial aneurysms and tortuosity, mild craniofacial, skeletal and cutaneous anomalies, and early-onset osteoarthritis. AOS is caused by mutations in the SMAD3 gene. Methods: A cohort of 393 patients with aneurysms without mutation in FBN1, TGFBR1 and TGFBR2 was screened for mutations in SMAD3. The patients originated from The Netherlands, Belgium, Switzerland and USA. The clinical phenotype in a total of 45 patients from eight different AOS families with eight different SMAD3 mutations is described. In all patients with a SMAD3 mutation, clinical records were reviewed and extensive genetic, cardiovascular and orthopaedic examinations were performed. Results Five novel SMAD3 mutations (one nonsense, two missense and two frame-shift mutations) were identified in five new AOS families. A follow-up description of the three families with a SMAD3 mutation previously described by the authors was included. In the majority of patients, early-onset joint abnormalities, including osteoarthritis and osteochondritis dissecans, were the initial symptom for which medical advice was sought. Cardiovascular abnormalities were present in almost 90% of patients, and involved mainly aortic aneurysms and dissections. Aneurysms and tortuosity were found in the aorta and other arteries throughout the body, including intracranial arteries. Of the patients who first presented with joint abnormalities, 20% died suddenly from aortic dissection. The presence of mild craniofacial abnormalities including hypertelorism and abnormal uvula may aid the recognition of this syndrome. Conclusion: The authors provide further insight into the phenotype of AOS with SMAD3 mutations, and present recommendations for a clinical work-up.

Stable angina pectoris: Head-to-head comparison of prognostic value of cardiac CT and exercise testing (Article)

2011-11-01T00:00:00Z

Purpose: To determine and compare the prognostic value of cardiac computed tomographic (CT) angiography, coronary calcium scoring, and exercise electrocardiography (ECG) in patients with chest pain who are suspected of having coronary artery disease (CAD). Materials and Methods: This study complied with the Declaration of Helsinki, and the local ethics committee approved the study. Patients (n = 471) without known CAD underwent exercise ECG and dual-source CT at a rapid assessment outpatient chest pain clinic. Coronary calcification and the presence of 50% or greater coronary stenosis (in one or more vessels) were assessed with CT. Exercise ECG results were classified as normal, ischemic, or nondiagnostic. The primary outcome was a major adverse cardiac event (MACE), defined as cardiac death, nonfatal myocardial infarction, or unstable angina requiring hospitalization and revascularization beyond 6 months. Univariable and multivariable Cox regression analysis was used to determine the prognostic values, while clinical impact was assessed with the net reclassification improvement metric. Results: Follow-up was completed for 424 (90%) patients;the mean duration of follow-up was 2.6 years. A total of 44 MACEs occurred in 30 patients. Four of the MACEs were cardiac deaths and six were nonfatal myocardial infarctions. The presence of coronary calcification (hazard ratio [HR], 8.22 [95% confidence interval {CI}: 1.96, 34.51]), obstructive CAD (HR, 6.22 [95% CI: 2.77, 13.99]), and nondiagnostic stress test results (HR, 3.00 [95% CI: 1.26, 7.14]) were univariable predictors of MACEs. In the multivariable model, CT angiography findings (HR, 5.0 [95% CI: 1.7, 14.5]) and nondiagnostic exercise ECG results (HR, 2.9 [95% CI: 1.2, 7.0]) remained independent predictors of MACEs. CT angiography findings showed incremental value beyond clinical predictors and stress testing (global χ2, 37.7 vs 13.7; P<.001), whereas coronary calcium scores did not have further incremental value (global χ2, 38.2 vs 37.7; P = .40). Conclusion: CT angiography findings are a strong predictor of future adverse events, showing incremental value over clinical predictors, stress testing, and coronary calcium scores.

Quantitative cardiovascular magnetic resonance in pregnant women: cross-sectional analysis of physiological parameters throughout pregnancy and the impact of the supine position. (Article)

2011-10-11T00:00:00Z

There are physiological reasons for the effects of positioning on hemodynamic variables and cardiac dimensions related to altered intra-abdominal and intra-thoracic pressures. This problem is especially evident in pregnant women due to the additional aorto-caval compression by the enlarged uterus. The purpose of this study was to investigate the effect of postural changes on cardiac dimensions and function during mid and late pregnancy using cardiovascular magnetic resonance (CMR). Healthy non-pregnant women, pregnant women at 20th week of gestation and at 32nd week of gestation without history of cardiac disease were recruited to the study and underwent CMR in supine and left lateral positions. Cardiac hemodynamic parameters and dimensions were measured and compared between both positions. Five non-pregnant women, 6 healthy pregnant women at mid pregnancy and 8 healthy pregnant women at late pregnancy were enrolled in the study. In the group of non-pregnant women left ventricular (LV) cardiac output (CO) significantly decreased by 9% (p=0.043) and right ventricular (RV) end-diastolic volume (EDV) significantly increased by 5% (p=0.043) from the supine to the left lateral position. During mid pregnancy LV ejection fraction (EF), stroke volume (SV), left atrium lateral diameter and left atrial supero-inferior diameter increased significantly from the supine position to the left lateral position: 8%, 27%, 5% and 11%, respectively (p<0.05). RV EDV, SV and right atrium supero-inferior diameter significantly increased from the supine to the left lateral position: 25%, 31% and 13% (p<0.05), respectively. During late pregnancy a significant increment of LV EF, EDV, SV and CO was observed in the left lateral position: 11%, 21%, 35% and 24% (p<0.05), respectively. Left atrial diameters were significantly larger in the left lateral position compared to the supine position (p<0.05). RV CO was significantly increased in the left lateral position compared to the supine position (p<0.05). During pregnancy positional changes affect significantly cardiac hemodynamic parameters and dimensions. Pregnant women who need serial studies by CMR should be imaged in a consistent position. From as early as 20 weeks the left lateral position should be preferred on the supine position because it positively affects venous return, SV and CO.

Correlates on MSCT of paravalvular aortic regurgitation after transcatheter aortic valve implantation using the medtronic corevalve prosthesis (Article)

2011-07-27T00:00:00Z

Background: To investigate the causes of paravalvular aortic regurgitation (PAR) after the implantation of the Medtronic CoreValve prosthesis (MCRS). Methods and Results: Fifty-six patients underwent MSCT before TAVI with a MCRS and PAR was assessed with transthoracic echocardiography (TTE) between 5 and 10 days after TAVI. The aortic annulus smallest and largest orthogonal diameters and the mean diameter from the area were determined on MSCT on an axial image at the nadir of all three native leaflets. PAR was related to relevant anatomical structures on MSCT according to a clockface in the orientation of the parasternal short axis view on TTE. PAR ≥ 1 was present in 25% of the patients and was associated with a larger annulus, a lower degree of over sizing and with more aortic root calcification. On MSCT post TAVI malapposition was seen predominantly at the aorto-mitral fibrous continuity and the aspect of the largest diameter of the aortic annulus on the inside curve of the ascending aorta. PAR was predominantly seen at these two anatomic locations and less frequent in the area that contains the ventricular membranous septum and the area between the non- and right coronary sinus. Conclusions: Mild to moderate PAR is common after TAVI with the MCRS. The availability of additional (larger) prosthesis sizes in combination with improved sizing based on mean annulus diameter (e.g., DCSA) may help to reduce PAR.

Transaortic flow velocity from dual-source MDCT for the diagnosis of aortic stenosis severity (Article)

2011-07-01T00:00:00Z

Objectives: To describe a method for the estimation of transaortic flow from multidetector computer tomography (MDCT). Background: Cardiac MDCT may not allow instantaneous flow measurement yet the components of flow, namely, volume change over time and lumenal area are recorded. Methods: In 36 patients, the transaortic flow velocity was determined on transthoracic echocardiography and also with cardiac MDCT as follows: On MDCT an axial orientation through the aortic root was obtained so that the nadir of all three aortic leaflets could be seen simultaneously in one axial image. Aortic valve area (AVA) was determined by planimetry and left ventricular volumes by endocardial border mapping at every 5% increment of the RR intervals. Flow velocity was then calculated as the incremental ejection volume Ã· duration of the increment Ã· AVA. Results: The transthoracic echocardiography (TTE) peak velocity and MDCT peak velocity were highly correlated (r = 0.75, P < 0.01). Transaortic peak velocity was higher when measured by MDCT as compared to TTE, with respectively a median [IQ-range] of 4.5 [2.9-5.3] and 4.0 [3.0-4.6], P < 0.01. For the diagnosis of severe aortic stenosis greater concordance with TTE peak velocity was seen with MDCT peak velocity (sensitivity 100%, specificity 76%) than with MDCT AVA (sensitivity 74%, specificity 76%). Conclusions: We show for the first time that transaortic flow velocity can be estimated by dual-source MDCT and has a better sensitivity for the detection of severe aortic stenosis than AVA planimetry when compared to the gold standard of TTE peak flow velocity. Copyright

First-line evaluation of coronary artery disease with coronary calcium scanning or exercise electrocardiography (Article)

2011-06-20T00:00:00Z

Background: Although conventional (CAG) and computed tomography angiography (CTA) are reliable diagnostic modalities for exclusion of obstructive coronary artery disease (CAD), they are costly and with considerable exposure to radiation and contrast media. We compared the accuracy of coronary calcium scanning (CCS) and exercise electrocardiography (X-ECG) as less expensive and non-invasive means to rule out obstructive CAD. Methods: In a rapid-access chest pain clinic, 791 consecutive patients with stable chest pain were planned to undergo X-ECG and dual-source CTA with CCS. According to the Duke pre-test probability of CAD patients were classified as low (< 30%), intermediate (30-70%) or high risk (> 70%). Angiographic obstructive CAD (> 50% stenosis by CAG or CTA) was found in 210/791 (27%) patients, CAG overruling any CTA results. Results: Obstructive CAD was found in 12/281 (4%) patients with no coronary calcium and in 73/319 (23%) with a normal X-ECG (p < 0.001). No coronary calcium was associated with a substantially lower likelihood ratio compared to X-ECG; 0.11, 0.13 and 0.13 vs. 0.93, 0.55 and 0.46 in the low, intermediate and high risk group. In low risk patients a negative calcium score reduced the likelihood of obstructive CAD to less than 5%, removing the need for further diagnostic work-up. CCS could be performed in 754/756 (100%) patients, while X-ECG was diagnostic in 448/756 (59%) patients (p < 0.001). Conclusions: In real-world patients with stable chest pain CCS is a reliable initial test to rule out obstructive CAD and can be performed in virtually all patients.

Safety and observer variability of cardiac magnetic resonance imaging combined with low-dose dobutamine stress-testing in patients with complex congenital heart disease (Article)

2011-03-03T00:00:00Z

Background: In patients with complex congenital heart disease (CHD) abnormal ventricular stress responses have been reported with dobutamine stress cardiovascular magnetic resonance (DCMR). These abnormal stress responses are potential indicators of long-term outcome. However, safety and reproducibility of this technique has not been reported in a larger study. The aim of this study was to report our experiences regarding safety and intra-observer and inter-observer variability of low-dose DCMR in complex CHD. Methods: In 91 patients, 110 low-dose DCMR studies were performed with acquisition of a short axis set at rest, and during dobutamine administration (7.5 μg/kg/min maximum). We assessed biventricular end-diastolic volumes, end-systolic volumes, stroke volumes, ejection fraction and ventricular mass. Intra- and inter-observer variability for all variables was assessed by calculating the coefficient of variation (%), i.e. the standard deviation of the difference divided by the mean of 2 measurements multiplied by 100%. Results: In 3 patients minor side effects occurred (vertigo, headache, and bigeminy). Ten patients experienced an increase in heart rate of > 150% from baseline, although well tolerated. For all variables, intra-observer variability was < 10% at rest and during stress. At rest, inter-observer variability was 10.5% maximal. With stress-testing, only the variability of biventricular end-systolic volumes (ESV) exceeded 10%. Conclusions: In patients with complex CHD low-dose DCMR is feasible, and safe. Intra-observer variability is low for rest and stress measurements. Inter-observer variability of biventricular ESV is high with stress-testing. Whether this limits the potential usefulness of DCMR for risk assessment during follow-up has to be assessed.

Impact of tube current in the quantitative assessment of acute reperfused myocardial infarction with 64-slice delayed-enhancement CT: A porcine model [Impatto della corrente del tubo sulla valutazione quantitativa dell'infarto miocardico acuto riperfuso mediante TC 64 strati e tecnica di delayed enhancement: esperienza in modello animale porcino] (Article)

2010-10-01T00:00:00Z

Purpose: This study evaluated the impact of tube current (mAs) in delayed-enhancement computed tomography (CT) imaging for assessing acute reperfused myocardial infarction in a porcine model. Materials and methods: In five domestic pigs (mean weight 24 kg), the circumflex coronary artery was balloon-occluded for 2 h and then reperfused. After 5 days, CT imaging was performed following administration of iodinated contrast material. A 64-slice CT system was used to perform first-pass coronary angiography with a tube current of 15 mAs/kg [Arterial Phase (ART)] followed by two delayed-enhancement (DE) scans 15 min after contrast material administration, with a tube current of 15 mAs/kg and 37.5 mAs/kg, respectively (DE1 and DE2). The mean heart rate decreased to 51±9 beats/min after administration of zatebradine (10 mg/kg IV). The data set was reconstructed during the end-diastolic phase of the cardiac cycle. Areas with DE, no reflow and remote myocardium [remote left ventricular (LV)] were calculated. CT values expressed in Hounsfield units (HU) were measured using five regions of interest (ROI): DE, no reflow, remote LV, LV cavity (LV lumen) and in air, respectively. Differences, correlations, image quality [signal-to-noise ratio (SNR)] and contrast resolution [contrast-to-noise ratio (CNR)] were calculated. Results: Significant differences were found between attenuation of areas of DE, no reflow and remote LV (p<0.001) within the different scans. There was a fair correlation between DE and no-reflow attenuation (r=0.6; p<0.001). In DE 1 vs. DE2, areas of DE and no reflow were not significantly different (p>0.05). The SNR and CNR were not significantly different in DE1 vs. DE2 (p>0.05). Conclusions: Tube current does not significantly affect infarction area, image quality or contrast resolution of DE imaging with CT.

Cardiovascular MRI in acute myocardial infarction (Article)

2010-06-01T00:00:00Z

At present, cardiovascular MRI is the only noninvasive diagnostic tool that can combine the assessment of regional and global function, morphology and tissue-specific information in a single investigation. With good spatial and temporal resolution and high contrast-to-noise ratio, cardiovascular MRI is an accurate and feasible tool for the evaluation of ischemic heart disease. It is not only considered to be the gold standard for assessment of myocardial function, but also for the detection of myocardial necrosis and fibrosis. In addition, cardiovascular MRI provides clinically relevant information on stunning, microvascular obstruction, transmural extent of the infarction, hemorrhage and postmyocardial infarction complications such as thrombus, Dressler syndrome and aneuryms.

Three dimensional evaluation of the aortic annulus using multislice computer tomography: Are manufacturer's guidelines for sizing for percutaneous aortic valve replacement helpful? (Article)

2010-04-01T00:00:00Z

AimsTo evaluate the effects of applying current sizing guidelines to different multislice computer tomography (MSCT) aortic annulus measurements on Corevalve (CRS) size selection.Methods and resultsMultislice computer tomography annulus diameters [minimum: Dmin; maximum: Dmax; mean: Dmean= (Dmin+ Dmax)/2; mean from circumference: Dcirc; mean from surface area: DCSA] were measured in 75 patients referred for percutaneous valve replacement. Fifty patients subsequently received a CRS (26 mm: n = 22; 29 mm: n = 28). Dmin and Dmax differed substantially [mean difference (95 CI) = 6.5 mm (5.7-7.2), P < 0.001]. If Dmin were used for sizing 26 of 75 patients would be ineligible (annulus too small in 23, too large in 3), 48 would receive a 26 mm and 12 a 29 mm CRS. If Dmax were used, 39 would be ineligible (all annuli too large), 4 would receive a 26 mm, and 52 a 29 mm CRS. Using Dmean, Dcirc, or DCSAmost patients would receive a 29 mm CRS and 11, 16, and 9 would be ineligible. In 50 patients who received a CRS operator choice corresponded best with sizing based on DCSA and Dmean(76, 74), but undersizing occurred in 20 and 22 of which half were ineligible (annulus too large).ConclusionEligibility varied substantially depending on the sizing criterion. In clinical practice both under-and oversizing were common. Industry guidelines should recognize the oval shape of the aortic annulus.

Intra-observer and interobserver variability of biventricular function, volumes and mass in patients with congenital heart disease measured by CMR imaging (Article)

2010-01-01T00:00:00Z

Cardiovascular magnetic resonance (CMR) imaging provides highly accurate measurements of biventricular volumes and mass and is frequently used in the follow-up of patients with acquired and congenital heart disease (CHD). Data on reproducibility are limited in patients with CHD, while measurements should be reproducible, since CMR imaging has a main contribution to decision making and timing of (re)interventions. The aim of this study was to assess intra-observer and interobserver variability of biventricular function, volumes and mass in a heterogeneous group of patients with CHD using CMR imaging. Thirty-five patients with CHD (7-62 years) were included in this study. A short axis set was acquired using a steady-state free precession pulse sequence. Intra-observer and interobserver variability was assessed for left ventricular (LV) and right ventricular (RV) volumes, function and mass by calculating the coefficient of variability. Intra-observer variability was between 2.9 and 6.8% and interobserver variability was between 3.9 and 10.2%. Overall, variations were smallest for biventricular end-diastolic volume and highest for biventricular end-systolic volume. Intra-observer and interobserver variability of biventricular parameters assessed by CMR imaging is good for a heterogeneous group of patients with CHD. CMR imaging is an accurate and reproducible method and should allow adequate assessment of changes in ventricular size and global ventricular function.

Comparison of the Value of Coronary Calcium Detection to Computed Tomographic Angiography and Exercise Testing in Patients With Chest Pain (Article)

2009-12-01T00:00:00Z

The aim of this study was to investigate the value of coronary calcium detection by computed tomography compared to computed tomographic angiography (CTA) and exercise testing to detect obstructive coronary artery disease (CAD) in patients with stable chest pain. A total of 471 consecutive patients with new stable chest complaints were scheduled to undergo dual-source multislice computed tomography (Siemens, Germany; coronary calcium score [CCS] and coronary CTA) and exercise electrocardiography (XECG). Clinically driven invasive quantitative angiography was performed in 98 patients. Only 3 of 175 patients (2%) with a negative CCS had significant CAD on CT angiogram, with only 1 confirmed by quantitative angiography. In patients with a high calcium score (Agatston score >400), CTA could exclude significant CAD in no more than 4 of 65 patients (6%). In patients with a low-intermediate CCS, CTA more often yielded diagnostic results compared to XECG and could rule out obstructive CAD in 56% of patients. For patients with CAD on CT angiogram, those with abnormal exercise electrocardiographic results more often showed severe CAD (p <0.034). In patients with diagnostic results for all tests, the sensitivity and specificity to detect >50% quantitative angiographic diameter stenosis were 100% and 15% for CCS >0, 82% and 64% for CCS >100, 97% and 36% for CTA, and 70% and 76% for XECG, respectively. In conclusion, nonenhanced computed tomography for calcium detection is a reliable means to exclude obstructive CAD in stable, symptomatic patients. Contrast-enhanced CTA can exclude significant CAD in patients with a low-intermediate CCS but is of limited value in patients with a high CCS.

Computed tomography versus exercise electrocardiography in patients with stable chest complaints: Real-world experiences from a fast-track chest pain clinic (Article)

2009-10-01T00:00:00Z

Objective: To compare the diagnostic performance of CT angiography (CTA) and exercise electrocardiography (XECG) in a symptomatic population with a low-intermediate prevalence of coronary artery disease (CAD). Design: Prospective registry. Setting: Tertiary university hospital. Patients: 471 consecutive ambulatory patients with stable chest pain complaints, mean (SD) age 56 (10), female 227 (48%), pre-test probability for significant CAD >5%. Intervention: All patients were intended to undergo both 64-slice, dual-source CTA and an XECG. Clinically driven quantitative catheter angiography was performed in 98 patients. Main outcome measures: Feasibility and interpretability of, and association between, CTA and XECG, and their diagnostic performance with invasive coronary angiography as reference. Results: CTA and XECG could not be performed in 16 (3.4%) vs 48 (10.2%, p<0.001), and produced nondiagnostic results in 3 (0.7%) vs 140 (33%, p<0.001). CTA showed ≥1 coronary stenosis (≥50%) in 140 patients (30%), XECG was abnormal in 93 patients (33%). Results by CTA and XECG matched for 185 patients (68%, p=0.63). Catheter angiography showed obstructive CAD in 57/98 patients (58%). Sensitivity, specificity, positive and negative predictive value of CTA to identify patients with ≥50% stenosis was 96%, 37%, 67% and 88%, respectively; compared with XECG: 71%, 76%, 80% and 66%, respectively. Quantitative CTA slightly overestimated diameter stenosis: 6 (21)% (R=0.71), compared with QCA. Of the 312 patients (66%) with a negative CTA, 44 (14%) had a positive XECG, but only 2/17 who underwent catheter angiography had significant CAD. Conclusion: CTA is feasible and diagnostic in more patients than XECG. For interpretable studies, CTA has a higher sensitivity, but lower specificity for detection of CAD.

Stress imaging in congenital cardiac disease (Article)

2009-10-01T00:00:00Z

In patients with coronary arterial disease, stress imaging is able to demonstrate abnormalities in the motion of the ventricular walls, and abnormalities in coronary arterial perfusion not apparent at rest. It can also provide information on prognostic factors. In patients with congenitally malformed hearts, stress imaging is used to determine contractile reserve, abnormalities of mural motion, and global systolic function, but also to assess diastolic and vascular function. In most of these patients, stress is usually induced using pharmacological agents, mainly dobutamine given in varying doses. The clinical usefulness of abnormal responses to the stress induced in such patients has to be addressed in follow-up studies. The abnormal stress might serve as surrogate endpoints, predicting primary endpoints at an early stage, which are useful for stratification of risk in this population of growing patients. We review here the stress imaging studies performed to date in patients with congenitally malformed hearts, with a special emphasis on echocardiography and cardiac magnetic resonance imaging.

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.

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.

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.