Biomedical subjects

Marianne de Vries

Publications and source records attributed to Marianne de Vries.

6 recordsLinked to original sources

PubMed2006

Peripheral arterial disease: clinical and cost comparisons between duplex US and contrast-enhanced MR angiography--a multicenter randomized trial.

PURPOSE: To prospectively determine the clinical and economic consequences of replacing duplex ultrasonography (US) with contrast material-enhanced magnetic resonance (MR) angiography for the initial imaging work-up of patients with peripheral arterial disease (PAD). MATERIALS AND METHODS: This randomized multicenter study was approved by the institutional review board of each hospital, and all patients signed written informed consent prior to randomization. Patients with PAD who needed to undergo imaging work-up and who had an ankle-brachial pressure index (ABPI) of less than 0.90 were recruited by vascular surgeons between January 2002 and September 2003. Patients were randomly assigned to undergo contrast-enhanced MR angiography or duplex US. The primary outcome measure was cost. Secondary outcome measures included therapeutic confidence, changes in disease severity, and changes in quality of life (QOL) assessed during 6 months of follow-up. Indicators for disease severity were based on the Rutherford classification, treadmill walking distance, ABPI at rest, and ABPI after exercise. QOL was assessed with the Rating Scale, Short Form 36, EuroQol-5D, and VascuQol questionnaires. The cost of (additional) imaging procedures, therapeutic interventions, and outpatient visits were calculated from a hospital perspective (ie, all costs incurred inside the hospital were estimated, including physician costs). Data were evaluated by using the Student t test and a multivariable linear regression analysis. RESULTS: At 6 months, 352 patients (239 [68%] men, 113 [32%] women; mean age, 65 years) were analyzed. The use of contrast-enhanced MR angiography versus duplex US reduced the number of additional vascular imaging procedures by 42%; contrast-enhanced MR angiography was also associated with higher therapeutic confidence. Diagnostic costs for contrast-enhanced MR angiography were 167 euros (186 dollars) higher than those for duplex US (P < .001). No statistically significant differences were found for total cost, changes in disease severity, or changes in QOL between patients examined with duplex US and those examined with contrast-enhanced MR angiography (P > .05). CONCLUSION: Replacing duplex US with contrast-enhanced MR angiography for the initial imaging work-up of patients with PAD reduces the need for additional imaging, although diagnostic costs are higher.

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PubMed2005

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

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.

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PubMed2005

Contrast-enhanced peripheral MR angiography using SENSE in multiple stations: feasibility study.

PURPOSE: To investigate if the use of parallel imaging is feasible and beneficial for peripheral contrast-enhanced magnetic resonance angiography (CE-MRA). MATERIALS AND METHODS: A total of 19 consecutive patients underwent peripheral CE-MRA using SENSE with two-fold reduction in the upper and lower leg stations. Conventional nonaccelerated imaging using constant level appearance (CLEAR) was used in the aortoiliac station. The findings were compared with those in a similar patient group that underwent peripheral CE-MR angiography using our standard imaging protocol without SENSE. Intraarterial digital subtraction angiography (IA-DSA) was used as the standard of reference. Lower extremity vessels were divided into anatomic segments (aortoiliac, upper legs, lower legs) for review. In each anatomic segment signal- and contrast-to-noise ratios (SNR, CNR), venous contamination, subjective image quality, as well as sensitivity and specificity, were determined for both patient groups. RESULTS: SNR and CNR improved significantly for the aortoiliac and upper leg segments (all P-values < or = 0.001). Small reductions were seen in the frequency of disturbing venous enhancement (P = not significant). There were no significant differences with regards to subjective image quality or diagnostic accuracy (all P > 0.3). Overall sensitivity and specificity in the SENSE group were 81% and 95%, respectively. For the non-SENSE group, these values were 79% and 96%, respectively. CONCLUSION: Preliminary results show that three-station peripheral CE-MRA using a full length peripheral arterial coil in combination with SENSE in the upper and lower leg stations is feasible and useful for further optimization of peripheral MRA. Using SENSE allows for routine, high-quality depiction of the entire peripheral vascular tree including the pedal arch. Higher SENSE factors are needed for further optimization.

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PubMed2005

Comparison of generic and disease-specific questionnaires for the assessment of quality of life in patients with peripheral arterial disease.

OBJECTIVE: This study compared the ability of generic and disease-specific questionnaires to assess quality of life (QOL) at baseline and to detect change in QOL after treatment in patients with peripheral arterial disease (PAD). METHODS: This prospective multicenter trial recruited 514 patients with PAD who needed an imaging workup and had an ankle brachial pressure index of less than 0.90. Patients with severe comorbidity were excluded, leaving a study population of 450 patients. Patients completed two generic questionnaires, the Short Form 36 (SF-36) and the European Quality of Life 5D (EuroQol-5D), and one disease-specific questionnaire, the Vascular Quality of Life (VascuQol) at baseline and after 6 months of follow-up. Rutherford classification and treadmill walking distance were determined at baseline and after 6 months of follow-up and were considered indicators of disease severity. Receiver operating characteristic (ROC) curves and areas under the curves (AUCs) were used to evaluate each of the three questionnaires for its ability to discriminate between severe and mild disease at baseline and to discriminate between a large and small change in disease severity after follow-up. The underlying assumption was that disease severity is a major determinant of QOL. This implies that the validity of a QOL questionnaire is reflected by its ability to discriminate between mildly and severely diseased patients. RESULTS: At baseline, 443 patients and after follow-up, 386 patients completed questionnaires. At baseline, no significant ( P >.05) differences were observed among AUCs for the total scores of the three questionnaires, indicating that all three questionnaires assessed the disease severity equally well. After follow-up, the AUCs for the VascuQol were significantly higher than the AUCs for the SF-36 and EuroQol-5D with respect to detection of improvement in Rutherford classification ( P < .05), indicating that change in disease severity after follow-up was best detected by the VascuQol. CONCLUSION: The VascuQol is the preferred questionnaire as outcome measure for QOL in future trials and clinical follow-up of patients with PAD.

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PubMed2005

Accuracy of semiautomated analysis of 3D contrast-enhanced magnetic resonance angiography for detection and quantification of aortoiliac stenoses.

OBJECTIVES: We sought to compare reproducibility and accuracy of semiautomated stenosis detection and quantification in 3D contrast-enhanced magnetic resonance angiography (CE-MRA) images with conventional evaluation of 3D CE-MRA in patients with peripheral arterial disease (PAD) by using intra-arterial digital subtraction angiography (IA-DSA) as standard of reference. METHODS: Twenty-five patients with PAD underwent CE-MRA and IA-DSA. Three blinded observers independently evaluated CE-MRA datasets for stenoses in the aortoiliac region using semiautomated computer analysis. Semiautomated measurements were compared with conventional measurements of stenosis on CE-MRA datasets, as measured by 3 other independent observers blinded to all other measurements. Interobserver agreement was quantified using kappa (kappa) and intraclass correlation coefficients (ICCs). Sensitivity and specificity were determined for both semiautomated and conventional measurements. RESULTS: Semiautomated measurements were successful in 124 of the 125 arterial segments. The sensitivity of semiautomated measurements was 89% for all observers; specificity varied between 87% and 89%. For conventional measurements of CE-MRA, sensitivity varied between 79% and 86%; specificity was between 86% and 96%. There was good interobserver agreement between all readers for semiautomated measurements (combined kappa for all 3 observers together = 0.78; ICC = 0.82), as well as for conventional measurements (combined kappa = 0.70; and ICC = 0.83). Differences between ICCs, combined kappa values, and accuracy of both measurements were not significant (all P > 0.05). CONCLUSION: Semiautomated analysis of aortoiliac 3D CE-MRA has the same high accuracy for detection and quantification of stenoses as conventional readings of CE-MRA.

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PubMed2003

Contrast-enhanced peripheral MR angiography at 3.0 Tesla: initial experience with a whole-body scanner in healthy volunteers.

PURPOSE: To report preliminary experience with contrast-enhanced magnetic resonance angiography (CE-MRA) of the peripheral arteries on a 3.0 T whole-body scanner equipped with a prototype body coil. MATERIALS AND METHODS: Four healthy volunteers were imaged on the 3.0 T system and, for comparative purposes, two of the subjects were also imaged on a commercially available 1.5 T whole-body system. To investigate field strength influence on objective image quality, signal-to-noise (SN) and contrast-to-noise (CN) ratios were calculated for named vessels from the infrarenal aorta to the ankles at both field strengths. Comparable imaging protocols were used at both field strengths. In addition, two reviewers, blinded for field strength, gave subjective image quality scores (three-point scale). RESULTS: SN and CN ratios were approximately equal on both systems (variation < or =9%) for the iliac and proximal upper leg stations. For the popliteal and lower leg stations SN ratios were 36% and 97% higher, and CN ratios were 44% and 127% higher, at 3.0 T. Subjective image quality at 3.0 T was substantially better for the distal upper and lower legs. CONCLUSION: Contrast-enhanced peripheral MRA is possible at 3.0 T when an imaging protocol similar to a current state-of-the-art 1.5 T protocol is used. Objective and subjective image quality at 3.0 T is comparable for the iliac and upper legs but better for the popliteal and lower leg arteries.

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