Kock, M.C.J.M.

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.

Lower extremity arterial disease: Multidetector CT angiography - Meta-analysis (Article)

2007-11-01T00:00:00Z

Purpose: To obtain the best available estimates of the diagnostic performance of multidetector computed tomographic (CT) angiography compared with that of digital subtraction angiography (DSA) in the assessment of symptomatic lower extremity arterial disease and to identify the most important sources of variation in diagnostic performance between studies. Materials and Methods: Reports of studies published from January 2000 through April 2006 in English, German, French, or Spanish were searched for by using the MEDLINE, EMBASE, and Cochrane databases. Studies were included if they allowed construction of 2 X 2 contingency tables for the detection of stenosis of 50% or greater at multidetector CT angiography compared with that at DSA - the reference standard - in patients with claudication or critical ischemia. Two observers extracted data about study design, patient characteristics, arterial tracts, and technical protocols. Random-effects summary receiver operating characteristic analysis was performed to examine the influence of these data on diagnostic performance. Results: Of the 70 studies initially identified, 12 were included in which multidetector CT angiography was used to evaluate 9541 arterial segments in 436 patients. The pooled sensitivity and specificity for detecting a stenosis of at least 50% per segment were 92% (95% confidence interval: 89%, 95%) and 93% (9S% confidence interval: 91%, 95%), respectively. Three studies provided data about the diagnostic performance of multidetector CT angiography in subdivisions of the arterial tract. The diagnostic performance of multidetector CT angiography in the infrapopliteal tract was lower than but not significantly different from that in the aortoiliac (P > .11) and femoropopliteal (P > .40) tracts. Regression analysis showed that diagnostic performance was not significantly influenced by differences in study characteristics. Conclusion: Multidetector CT angiography is an accurate diagnostic test in the assessment of arterial disease (≥50% stenosis) of the entire lower extremity.

Diagnostic Imaging of Peripheral Arterial Disease with Multi-Detector Row Computed Tomography Angiography (Doctoral Thesis)

2007-01-24T00:00:00Z

Peripheral arterial disease (PAD) is in the majority of patients caused by atherosclerosis in the lower extremities distal to the aortic bifurcation. Atherosclerosis is a complex systemic, progressive and degenerative disease of the intima of the arterial wall, which affects both large and medium-sized arteries. The prevalence of symptomatic PAD is 3-5% in older adults in different Western populations (1-2). Atherosclerosis has a pre-clinical course with absence of clinical symptoms for several decades. PAD generally becomes evident with symptoms of intermittent claudication. Intermittent claudication is defined as muscle cramps in the lower limb that occur following exercise and are relieved with rest. In a minority (a quarter) of patients, the disease progresses to critical limb ischemia i.e. rest pain or tissue necrosis (3-5). The diagnosis of PAD is based on patient history and physical examination. The severity of PAD is generally classified by measuring the ankle-brachial indices.

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.

Cost-effectiveness targets for multi-detector row CT angiography in the work-up of patients with intermittent claudication. (Article)

2003-06-01T00:00:00Z

PURPOSE: To determine the costs, sensitivity for detection of significant stenoses, and proportion of equivocal multi-detector row computed tomographic (CT) angiography results in the work-up of patients with intermittent claudication that would make this imaging examination cost-effective compared with gadolinium-enhanced magnetic resonance (MR) angiography. MATERIALS AND METHODS: A decision model was used to compare the societal cost-effectiveness of a new imaging modality with that of gadolinium-enhanced MR angiography. Main outcome measures were quality-adjusted life years (QALYs) and lifetime costs. By using threshold analysis of a given willingness to pay per QALY, target values for costs, sensitivity for detection of significant stenoses, and proportion of cases requiring additional work-up with intraarterial digital subtraction angiography owing to equivocal results of the new modality were determined. The base case evaluated was that of 60-year-old men with severe intermittent claudication and assumed an incremental cost-effectiveness threshold of 100,000 US dollars per QALY. RESULTS: If treatment were limited to angioplasty, a new imaging modality would be cost-effective if the costs were 300 US dollars and the sensitivity was 85%, even if up to 35% of patients needed additional work-up. When both angioplasty and bypass surgery were considered as treatment options, a new imaging modality was cost-effective if the costs were 300 US dollars, the sensitivity was higher than 94%, and 20% of patients required additional work-up. CONCLUSION: Multi-detector row CT angiography, as compared with currently used imaging modalities such as MR angiography, has the potential to be cost-effective in the evaluation of patients with intermittent claudication.

Living renal donors: optimizing the imaging strategy--decision- and cost-effectiveness analysis (Article)

2003-01-01T00:00:00Z

PURPOSE: To determine the most cost-effective strategy for preoperative imaging performed in potential living renal donors. MATERIALS AND METHODS: In a decision-analytic model, the societal cost-effectiveness of digital subtraction angiography (DSA), gadolinium-enhanced magnetic resonance (MR) angiography, contrast material-enhanced spiral computed tomographic (CT) angiography, and combinations of these imaging techniques was evaluated. Outcome measures included lifetime cost, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios. A base-case analysis was performed with a 40-year-old female donor and a 40-year-old female recipient. RESULTS: For the donor, MR angiography (24.05 QALYs and 9,000 dollars) dominated all strategies except for MR angiography with CT angiography, which had an incremental ratio of 245,000 dollars per QALY. For the recipient, DSA and DSA with MR angiography yielded similar results (10.46 QALYs and 179,000 dollars) and dominated all other strategies. When results for donor and recipient were combined, DSA dominated all other strategies (34.51 QALYs and 188,000 dollars). If DSA was associated with a 99% specificity or less for detection of renal disease, MR angiography with CT angiography was superior (34.47 QALYs and 190,000 dollars). CONCLUSION: For preoperative imaging in a potential renal donor, DSA is the most cost-effective strategy if it has a specificity greater than 99% for detection of renal disease; otherwise, MR angiography with CT angiography is the most cost-effective strategy.

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.