Shandra Bipat

University of Amsterdam, Amsterdamo, North Holland, Netherlands

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Publications (118)366.5 Total impact

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    ABSTRACT: Objectives To evaluate patient burden and preferences for MR colonography with a limited bowel preparation and automated carbon dioxide insufflation in comparison to conventional colonoscopy. Methods Symptomatic patients were consecutively recruited to undergo MR colonography with automated carbon dioxide insufflation and a limited bowel preparation followed within four weeks by colonoscopy with a standard bowel cleansing preparation. Four questionnaires regarding burden (on a five-point scale) and preferences (on a seven-point scale) were addressed after MR colonography and colonoscopy and five weeks after colonoscopy. Results Ninety-nine patients (47 men, 52 women; mean age 62.3, SD 8.7) were included. None of the patients experienced severe or extreme burden from the MR colonography bowel preparation compared to 31.5% of the patients for the colonoscopy bowel preparation. Colonoscopy was rated more burdensome (25.6% severe or extreme burden) compared to MR colonography (5.2% severe or extreme burden) (P < 0.0001). When discarding the bowel preparations, the examinations were rated equally burdensome (P = 0.35). The majority of patients (61.4%) preferred MR colonography compared to colonoscopy (29.5%) immediately after the examinations and five weeks later (57.0% versus 39.5%). Conclusion MR colonography with a limited bowel preparation and automated carbon dioxide insufflation demonstrated less burden compared to colonoscopy. The majority of patients preferred MR colonography over colonoscopy.
    European Journal of Radiology 10/2014; 84(1). DOI:10.1016/j.ejrad.2014.10.006 · 2.16 Impact Factor
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    ABSTRACT: PurposeTo determine the role of diffusion-weighted imaging (DWI) in evaluating response to chemoradiotherapy in patients with uterine cervical cancer.Materials and MethodsA search was performed in MEDLINE and EMBASE from January 2005 to April 2014 using search terms related to uterine cervical cancer and magnetic resonance imaging. Two reviewers independently checked the studies for inclusion criteria, patient population, magnetic resonance imaging (MRI) parameters and analysis, follow-up for treatment response, apparent diffusion coefficient (ADC) values, and quality assessment.ResultsNine studies with 231 patients were included. International Federation of Gynecology and Obstetrics (FIGO) staging varied from Ib1 to IVb and mean age from 42 to 67 years. When baseline and after treatment pooled mean ADC values were compared, complete responders showed higher increase (0.88 × 10−3 mm2/s to 1.50 × 10−3 mm2/s; Δ0.62 × 10−3 mm2/s) compared to partial responders (1.03 × 10−3 mm2/s to 1.42 × 10−3 mm2/s; Δ0.39 × 10−3 mm2/s) and to nonresponders (0.87 × 10−3 mm2/s to 1.18 × 10−3 mm2/s; Δ0.31 × 10−3 mm2/s). Individual studies also showed that an ADC of ≤0.31 was only seen in nonresponders and an increase of ADC of ≥0.62 was only seen in complete responders. The number of datasets for monitoring early response (at 2 or 4 weeks of therapy) were low and comparable increases in pooled mean ADC values between complete responders, partial responders, and nonresponders were seen. Data on quality assessment showed high risk of bias concerning patient selection, DWI evaluation, and flow and timing.ConclusionDWI can be used for monitoring treatment response after treatment, but not for the early response monitoring. J. Magn. Reson. Imaging 2014.
    Journal of Magnetic Resonance Imaging 10/2014; DOI:10.1002/jmri.24784 · 2.79 Impact Factor
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    ABSTRACT: This study was designed to study the outcome of infrainguinal revascularization in patients with critical limb ischemia (CLI) in an institution with a preference towards endovascular intervention first in patients with poor condition, unfavourable anatomy for surgery, no venous material for bypass, and old age.
    CardioVascular and Interventional Radiology 08/2014; DOI:10.1007/s00270-014-0955-5 · 1.97 Impact Factor
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    ABSTRACT: This study was designed to summarize the evidence on clinical outcomes and complications of prostatic arterial embolization (PAE) in patients with benign prostatic hyperplasia (BPH). We searched Medline and Embase for PAE trials of patients with BPH upto November 2013. Two reviewers independently checked the inclusion and exclusion criteria and performed data extraction of study characteristics, quantitative and qualitative outcomes, and complications. The search yielded 562 studies, of which 9 articles with 706 patients were included. In these 9 articles, there was a possible overlap of data and the quality of 8 studies was assessed as poor. All patients had moderate-to-severe, lower urinary tract symptoms (LUTS). The mean age ranged from 63.4-74.1 years. After embolization, a decrease of the prostate volume (PV) and post void residual (PVR) was seen mainly in the first month with a further decrease up to 12 months, increasing afterwards. The prostate specific antigen (PSA) decreased up to 3 months after PAE, increasing afterwards. The peak urinary flow (Qmax) increased mainly the first month and decreased after 30 months. The international prostate symptom score (IPSS) and quality of life-related symptoms (QOL) improved mainly during the first month, with a further improvement up to 30 months. No deterioration of the international index of erectile function (IIEF) was seen after PAE. The PAE procedure seems safe. Although the number of studies was small, qualitatively poor, and with overlap of patients, the initial clinical outcomes as reported up to 12 months seem positive and the procedure seems safe.
    CardioVascular and Interventional Radiology 07/2014; 37(5). DOI:10.1007/s00270-014-0948-4 · 1.97 Impact Factor
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    ABSTRACT: Endoscopy is currently the primary diagnostic technique for inflammatory bowel disease (IBD) in children. To assess the accuracy of US and dynamic contrast-enhanced MRI for diagnosing inflammatory bowel disease and for distinguishing Crohn disease and ulcerative colitis in comparison to a reference standard. Consecutive children with suspected IBD underwent diagnostic workup including ileocolonoscopy and upper gastrointestinal endoscopy as the reference standard, abdominal US, and MR enterography and colonography at 3 T. The protocol included a dynamic contrast-enhanced 3-D sequence. Sensitivity, specificity and kappa values were calculated for one ultrasonographer and two MRI observers. We included 28 children (15 boys) with mean age 14 years (range 10-17 years). The diagnosis was IBD in 23 children (72%), including 12 with Crohn disease, 10 with ulcerative colitis and 1 with indeterminate colitis. For the diagnosis of inflammatory bowel disease the sensitivity was 55% for US and 57% (both observers) for MR entero- and colonography, and the specificity was 100% for US and 100% (observer 1) and 75% (observer 2) for MR entero- and colonography. Combined MRI and US had sensitivity and specificity of 70% and 100% (observer 1) and 74% and 80% (observer 2), respectively. With the addition of a dynamic contrast-enhanced MR sequence, the sensitivity increased to 83% and 87%. US and MRI could only distinguish between Crohn disease and ulcerative colitis when terminal ileum lesions were present. US and MR entero- and colonography have a high accuracy for diagnosing inflammatory bowel disease in children but cannot be used to distinguish Crohn disease and ulcerative colitis.
    Pediatric Radiology 06/2014; 44(11). DOI:10.1007/s00247-014-3010-4 · 1.65 Impact Factor
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    ABSTRACT: Purpose: To assess whether selective use of estimated glomerular filtration rate (eGFR) in patients with risk factors for kidney disease is more cost-effective than measuring eGFR in all patients undergoing contrastenhanced computed tomography (CECT). Methods: Risk factors and costs were assessed in consecutive patients. eGFR was evaluated in all patients, considering a tenability of 12 months. For the three-month tenability and the pre-selection strategy based on risk factors for kidney disease, we extrapolated data by assuming equal distribution of patient characteristics. Results: We included 1001 patients, mean age 59.9±13.6 years. Strategy with eGFR in all patients: eGFR measurements specifically performed for CECT in 645÷1001 (in 356 patients the eGFR was already known). The total cost including costs of an extra visit to the hospital (49 patients) and absence from work (11 patients) were € 6037.20. Considering a tenability of 3 months, eGFR had to be measured in 786 patients, 60 would have paid an extra visit and 14 would have been absent from work: total cost € 7443.54. Pre-selection strategy: 807 patients had risk factors, necessitating eGFR measurement and an extra visit would be paid by 61. Fourteen patients would have been absent from work: total cost € 7585.16. Of the patients with an eGFR.
    The Netherlands Journal of Medicine 06/2014; 72(5):271-80. · 2.21 Impact Factor
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    ABSTRACT: Objective To evaluate 1 to 48 month follow-up outcomes of different endovascular treatment strategies in below-the-knee (BTK) arterial segments in critical limb ischemia (CLI) patients. Methods Medline and Embase were searched (last searched on 5 November 2013) for studies of randomized controlled trials comparing either balloon angioplasty (PTA) or drug-eluting balloon (DEB) with optional bailout stenting, or primary stenting using a bare stent (BS) or drug-eluting stent (DES) to one another. Methodological quality of each trial was assessed using a Cochrane Collaboration's tool, and quality of evidence was assessed using the GRADE system. Outcomes assessed were wound healing, quality of life, change in Rutherford classification, amputation, death, target lesion revascularization (TLR), bypass, binary restenosis, late lumen loss, stenosis grade, and event-free survival with follow-up periods of at least 1 month. Results Twelve trials including 1145 patients were identified, with 90% of patients having CLI. Six BS versus PTA and two DES versus PTA trials showed low-quality evidence of equal efficacy. One trial, comparing DEB with PTA, showed moderate-quality evidence of improved wound healing (RR 1.28; 95% CI: 1.05 to 1.56; p = .01), improvement in Rutherford classification (RR 1.32; 95% CI: 1.08 to 1.60; p = .008), and lower TLR (RR 0.41; 95% CI 0.23 to 0.74; p = .002) and binary restenosis (RR 0.36; 95% CI 0.24 to 0.54; p < .0001) in diabetic patients after 12 months. Amputation and death rate did not differ significantly. For DES versus BS, most trials showed equal efficacy between strategies. Conclusion Based on low- to moderate-quality evidence, PTA with optional bailout stenting using BS should remain the preferred strategy in treating CLI patients with BTK arterial lesions. Before other strategies can be implemented, larger and high-quality RCTs assessing clinically relevant outcomes are needed.
    European journal of vascular and endovascular surgery: the official journal of the European Society for Vascular Surgery 05/2014; DOI:10.1016/j.ejvs.2014.02.012 · 3.07 Impact Factor
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    ABSTRACT: Objectives To evaluate the diagnostic performance of MR colonography using automated carbon dioxide (CO2) insufflation for colonic distension, with colonoscopy serving as the reference standard. Methods Ninety-eight symptomatic patients underwent MR colonography with faecal tagging and automated CO2 insufflation. Three readers (one expert (reader1), and two less experienced (reader 2 and 3)) evaluated the images for presence of colorectal lesions. Bowel distension was evaluated on a 4-point scale. Results were verified with colonoscopy and histopathological analysis. Results Per-patient sensitivity for lesions ≥10 mm was 91.7% (11 of 12) (reader 1), 75.0% (9 of 12) (reader 2), and 75% (9 of 12) (reader 3). Specificity was 96.5% (82 of 85) (reader 1), 97.7% (83 of 85) (reader 2), 95.3% (81 of 85) (reader 3). Per-patient sensitivity for lesions ≥6 mm was 85.7% (18 of 21) (reader 1), 57.1% (12 of 21) (reader 2), and 57.1% (12 of 21) (reader 3). Specificity was 86.8% (66 of 76), 98.7% (75 of 76), 90.8% (69 of 76), respectively. Per-patient sensitivity for advanced neoplasia of ≥10 mm and ≥6 mm was 88.9% (8 of 9) for all readers. Specificity for ≥10 mm and ≥6 mm was 98.9% (87 of 88) (reader 1), 97.7% (86 of 88) (reader 2), 96.6% (85 of 88) (reader 3). 94.4% of the colon segments were adequate to optimal distended with dual positioning. Conclusion MR colonography can accurately detect lesions ≥10 mm, and advanced neoplasia ≥6 mm. Sufficient distension was achieved using automated CO2 insufflation for colonic distension in MR colonography.
    European journal of radiology 05/2014; 83(5). DOI:10.1016/j.ejrad.2014.01.013 · 2.16 Impact Factor
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    ABSTRACT: To assess which risk factors can be used to reduce superfluous estimated glomerular filtration rate (eGFR) measurements before intravenous contrast medium administration. In consecutive patients, all decreased eGFR risk factors were assessed: diabetes mellitus (DM), history of urologic/nephrologic disease (HUND), nephrotoxic medication, cardiovascular disease, hypertension, age > 60 years, anaemia, malignancy and multiple myeloma/M. Waldenström. We studied four models: (1) all risk factors, (2) DM, HUND, hypertension, age > 60 years; (3) DM, HUND, cardiovascular disease, hypertension; (4) DM, HUND, age > 75 years and congestive heart failure. For each model, association with eGFR < 60 ml/min/1.73 m(2) or eGFR < 45 ml/min/1.73 m(2) was studied. A total of 998 patients, mean age 59.94 years were included; 112 with eGFR < 60 ml/min/1.73 m(2) and 30 with eGFR < 45 ml/min/1.73 m(2). Model 1 detected 816 patients: 108 with eGFR < 60 ml/min/1.73 m(2) and all 30 with eGFR < 45 ml/min/1.73 m(2). Model 2 detected 745 patients: 108 with eGFR < 60 ml/min/1.73 m(2) and all 30 with eGFR < 45 ml/min/1.73 m(2). Model 3 detected 622 patients: 100 with eGFR < 60 ml/min/1.73 m(2) and all 30 with eGFR < 45 ml/min/1.73 m(2). Model 4 detected 440 patients: 86 with eGFR < 60 ml/min/1.73 m(2) and all 30 with eGFR < 45 ml/min/1.73 m(2). Associations were significant (p < 0.001). Model 4 is most effective, resulting in the lowest proportion of superfluous eGFR measurements while detecting all patients with eGFR < 45 ml/min/1.73 m(2) and most with eGFR < 60 ml/min/1.73 m(2). • A major risk factor for contrast-induced nephropathy (CIN) is kidney disease. • Risk factors are used to identify patients with pre-existent kidney disease. • Evidence for risk factors to identify patients with kidney disease is limited. • The number of eGFR measurements to detect kidney disease can be reduced.
    European Radiology 03/2014; DOI:10.1007/s00330-014-3149-2 · 4.34 Impact Factor
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    ABSTRACT: To prospectively evaluate if training with direct feedback improves grading accuracy of inexperienced readers for Crohn's disease activity on magnetic resonance imaging (MRI). Thirty-one inexperienced readers assessed 25 cases as a baseline set. Subsequently, all readers received training and assessed 100 cases with direct feedback per case, randomly assigned to four sets of 25 cases. The cases in set 4 were identical to the baseline set. Grading accuracy, understaging, overstaging, mean reading times and confidence scores (scale 0-10) were compared between baseline and set 4, and between the four consecutive sets with feedback. Proportions of grading accuracy, understaging and overstaging per set were compared using logistic regression analyses. Mean reading times and confidence scores were compared by t-tests. Grading accuracy increased from 66 % (95 % CI, 56-74 %) at baseline to 75 % (95 % CI, 66-81 %) in set 4 (P = 0.003). Understaging decreased from 15 % (95 % CI, 9-23 %) to 7 % (95 % CI, 3-14 %) (P < 0.001). Overstaging did not change significantly (20 % vs 19 %). Mean reading time decreased from 6 min 37 s to 4 min 35 s (P < 0.001). Mean confidence increased from 6.90 to 7.65 (P < 0.001). During training, overall grading accuracy, understaging, mean reading times and confidence scores improved gradually. Inexperienced readers need training with at least 100 cases to achieve the literature reported grading accuracy of 75 %. • Most radiologists have limited experience of grading Crohn's disease activity on MRI. • Inexperienced readers need training in the MRI assessment of Crohn's disease. • Grading accuracy, understaging, reading time and confidence scores improved during training. • Radiologists and residents show similar accuracy in grading Crohn's disease. • After 100 cases, grading accuracy can be reached as reported in the literature.
    European Radiology 02/2014; DOI:10.1007/s00330-014-3111-3 · 4.34 Impact Factor
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    ABSTRACT: PURPOSE To prospectively compare conventional MRI, dynamic contrast-enhanced (DCE-)MRI and diffusion weighted imaging (DWI) sequences to histopathology of surgical specimens in Crohn’s disease (CD). METHOD AND MATERIALS 3T MR enterography was performed in 25 consecutive CD patients scheduled for surgery within 4 weeks. A total of one to four sections per patient were chosen for detailed image analysis. Evaluated features including mural thickness, T1 signal ratio and T2 signal ratio and on DCE-MRI maximum enhancement (ME), initial slope of increase (ISI) and time to peak (TTP) and on DWI apparent diffusion coefficient (ADC), were compared to location matched-histopathologic grading of acute inflammation score (AIS) and fibrostenosis score (FS) by Spearman correlation, Kruskal Wallis and Mann-Whitney test. RESULTS Twenty patients (mean age 38 years, range 21-73, 12 females) were included and 50 bowel locations (35 terminal ileum, 11 ascending colon, 2 transverse colon, 2 descending colon) were matched to AIS and FS. Median AIS was 3 and median FS 1. Mural thickness, T1 signal ratio, T2 signal ratio, ME and ISI correlated significantly to AIS (r = 0.634, 0.392, 0.485, 0.526, 0.514, respectively; all p<0.05). Mural thickness, T1 and T2 signal ratio differed significantly between the grades of FS (p<0.001, p=0.001, p=0.021, respectively). ME, ISI and ADC values differed significantly between the non-fibrotic sections and the fibrotic sections (p<0.001, p=0.001, p=0.023, respectively). CONCLUSION Quantitative parameters from conventional, DCE-MRI and DWI sequences correlate significantly to histopathologic scores of surgical specimens. DCE-MRI and DWI give comparable results but do not outperform conventional MRI parameters. CLINICAL RELEVANCE/APPLICATION DCE- and DWI-MRI can be used for quantitative evaluation of Crohn's disease activity.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
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    ABSTRACT: OBJECTIVE. The purpose of this article is to assess the interobserver variability for scoring MRI features of Crohn disease activity and to correlate two MRI scoring systems to the Crohn disease endoscopic index of severity (CDEIS). MATERIALS AND METHODS. Thirty-three consecutive patients with Crohn disease undergoing 3-T MRI examinations (T1-weighted with IV contrast medium administration and T2-weighted sequences) and ileocolonoscopy within 1 month were independently evaluated by four readers. Seventeen MRI features were recorded in 143 bowel segments and were used to calculate the MR index of activity and the Crohn disease MRI index (CDMI) score. Multirater analysis was performed for all features and scoring systems using intraclass correlation coefficient (icc) and kappa statistic. Scoring systems were compared with ileocolonoscopy with CDEIS using Spearman rank correlation. RESULTS. Thirty patients (median age, 32 years; 21 women and nine men) were included. MRI features showed fair-to-good interobserver variability (intraclass correlation coefficient or kappa varied from 0.30 to 0.69). Wall thickness in millimeters, presence of edema, enhancement pattern, and length of the disease in each segment showed a good interobserver variability between all readers (icc = 0.69, κ = 0.66, κ = 0.62, and κ = 0.62, respectively). The MR index of activity and CDMI scores showed good reproducibility (icc = 0.74 and icc = 0.78, respectively) and moderate CDEIS correlation (r = 0.51 and r = 0.59, respectively). CONCLUSION. The reproducibility of individual MRI features overall is fair to good, with good reproducibility for the most commonly used features. When combined into the MR index of activity and CDMI score, overall reproducibility is good. Both scores show moderate agreement with CDEIS.
    American Journal of Roentgenology 12/2013; 201(6):1220-1228. DOI:10.2214/AJR.12.10341 · 2.74 Impact Factor
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    ABSTRACT: To compare the diagnostic accuracy of TE and MRE and establish cutoff levels and diagnostic strategies for both techniques, enabling selection of patients for liver biopsy. One hundred three patients with chronic hepatitis B or C and liver biopsy were prospectively included. Areas under curves (AUROC) were compared for TE and MRE for METAVIR fibrosis grade ≥ F2 and ≥F3. We defined cutoff values for selection of patients with F0-F1 (sensitivity >95 %) and for significant fibrosis F2-F4 (specificity >95 %). Following exclusions, 85 patients were analysed (65 CHB, 19 CHC, 1 co-infected). Fibrosis stages were F0 (n = 3), F1 (n = 53), F2 (n = 15), F3 (n = 8) and F4 (n = 6). TE and MRE accuracy were comparable [AUROCTE ≥ F2: 0.914 (95 % CI: 0.857-0.972) vs. AUROCMRE ≥ F2: 0.909 (0.840-0.977), P = 0.89; AUROCTE ≥ F3: 0.895 (0.816-0.974) vs. AUROCMRE ≥ F3: 0.928 (0.874-0.982), P = 0.42]. Cutoff values of <5.2 and ≥8.9 kPa (TE) and <1.66 and ≥2.18 kPa (MRE) diagnosed 64 % and 66 % of patients correctly as F0-F1 or F2-F4. A conditional strategy in inconclusive test results increased diagnostic yield to 80 %. TE and MRE have comparable accuracy for detecting significant fibrosis, which was reliably detected or excluded in two-thirds of patients. A conditional strategy further increased diagnostic yield to 80 %. • Both ultrasound-based transient elastography and magnetic resonance elastography can assess hepatic fibrosis. • Both have comparable accuracy for detecting liver fibrosis in viral hepatitis. • The individual techniques reliably detect or exclude significant liver fibrosis in 66 %. • A conditional strategy for inconclusive findings increases the number of correct diagnoses.
    European Radiology 10/2013; DOI:10.1007/s00330-013-3046-0 · 4.34 Impact Factor
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    ABSTRACT: Interpreting whether changes in quality of life (Qol) in patients with peripheral arterial disease (PAD) are not only statistically significant but also clinically relevant, may be difficult. This study introduces the concept of the minimally important difference (MID) to vascular surgeons using Qol outcomes of patients treated for chronic critical limb ischemia (CLI). The Vascular Quality of Life (VascuQol) questionnaire was recorded at baseline before treatment and after 6 months follow-up in consecutive patients with CLI treated between May 2007 and May 2010. Statistical significance of change in VascuQol score was tested with the Wilcoxon Signed Rank test. The MID for the VascuQol score was determined using a clinical anchor-based method and a distribution-based method. A total of 127 patients with CLI completed the VascuQol after 6 months. The VascuQol sum scores improved from 3.0 (range 1.1-5.9) at baseline to 4.0 (range 1.2-6.7) at 6 months (p < .001). The MID on the VascuQol sumscore indicating a clinically important change determined with the anchor-based method was 0.36, and with the distribution-based method was 0.48. On an individual level, depending on the method of determining the MID, this resulted in 60% to 68% of the patients with an important benefit. Expression of changes in Qol by means of the MID provides better insight into clinically important changes than statistical significance.
    European journal of vascular and endovascular surgery: the official journal of the European Society for Vascular Surgery 10/2013; 47(2). DOI:10.1016/j.ejvs.2013.10.012 · 3.07 Impact Factor
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    ABSTRACT: This study evaluated changes in functional status with the Academic Medical Center Linear Disability Score (ALDS) and in quality of life with the Vascular Quality of Life Questionnaire (VascuQol) in patients treated for critical limb ischemia (CLI). We conducted a prospective observational cohort study in a single academic center that included consecutive patients with CLI who presented between May 2007 and May 2010. The ALDS and VascuQol questionnaires were administered before treatment (baseline) and after treatment at 6 and 12 months of follow-up. Changes in functional status (ALDS) and quality of life (VascuQol) scores after 6 and 12 months, compared with baseline, were tested with the appropriate statistical tests, with significance set at P < .05. The study included 150 patients, 96 (64%) were men, and mean (± standard deviation) age was 68.1 (±12.4) years. The primary treatment was endovascular in 98 (65.3%), surgical in 36 (24%), conservative in 11 (7.3%), or a major amputation in five (3.3%). The ALDS was completed by 112 patients after 12 months. At that time, the median ALDS score had increased by 10 points (median, 83; range, 12-89; P = .001) in patients who achieved limb salvage, which corresponds with more difficult outdoor and indoor activities. In patients with a major amputation, the median ALDS score decreased by 14 points (median, 55; range, 16-89; P = .117) after 12 months, which corresponds with domestic activities only. VascuQol scores improved significantly in all separate domains for the limb salvage group (P < .001). All VascuQol scores, except for the activity and social domains, increased significantly after amputation. Our study confirms the clinical validity of the ALDS in patients treated for CLI and shows that it is a valuable and sophisticated instrument to measure changes in functional status in these patients.
    Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 10/2013; 58(4):957-965.e1. DOI:10.1016/j.jvs.2013.04.034 · 2.98 Impact Factor
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    ABSTRACT: To prospectively compare conventional MRI sequences, dynamic contrast enhanced (DCE) MRI and diffusion weighted imaging (DWI) with histopathology of surgical specimens in Crohn's disease. 3-T MR enterography was performed in consecutive Crohn's disease patients scheduled for surgery within 4 weeks. One to four sections of interest per patient were chosen for analysis. Evaluated parameters included mural thickness, T1 ratio, T2 ratio; on DCE-MRI maximum enhancement (ME), initial slope of increase (ISI), time-to-peak (TTP); and on DWI apparent diffusion coefficient (ADC). These were compared with location-matched histopathological grading of inflammation (AIS) and fibrosis (FS) using Spearman correlation, Kruskal-Wallis and Chi-squared tests. Twenty patients (mean age 38 years, 12 female) were included and 50 sections (35 terminal ileum, 11 ascending colon, 2 transverse colon, 2 descending colon) were matched to AIS and FS. Mural thickness, T1 ratio, T2 ratio, ME and ISI correlated significantly with AIS, with moderate correlation (r = 0.634, 0.392, 0.485, 0.509, 0.525, respectively; all P < 0.05). Mural thickness, T1 ratio, T2 ratio, ME, ISI and ADC correlated significantly with FS (all P < 0.05). Quantitative parameters from conventional, DCE-MRI and DWI sequences correlate with histopathological scores of surgical specimens. DCE-MRI and DWI parameters provide additional information. • Conventional MR enterography can be used to assess Crohn's disease activity. • Several MRI parameters correlate with inflammation and fibrosis scores from histopathology. • Dynamic contrast enhanced imaging and diffusion weighted imaging give additional information. • Quantitative MRI parameters can be used as biomarkers to evaluate Crohn's disease activity.
    European Radiology 09/2013; DOI:10.1007/s00330-013-3015-7 · 4.34 Impact Factor
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    ABSTRACT: This article systematically reviewed the literature to (1) identify variables that were associated with maximum insertion torque values during the insertion of orthodontic mini-implants into artificial bone, (2) quantify such associations and (3) assess adverse effects of this procedure. Computerized and manual searches were conducted up to 24 February 2012. Selection criteria included studies that (1) recorded maximum insertion torque during the insertion of orthodontic mini-implants into artificial bone, (2) used sample sizes of five screws or more, (3) assessed maximum insertion torque with electronic torque sensors, and (4) used orthodontic mini-implants with a diameter smaller than 2.5 mm. ASTM Standards F543-07(ε1) and F1839-08(ε1) and the Cochrane Handbook for Systematic Reviews were used as guidelines for this systematic review. Quality assessments were rated according to the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. A total of 23 studies were selected, many of which were multiple publications of the same study. Many domains in the risk of bias assessments were scored as "high" or "unclear" risk of bias. A wide variety of implant, test block, and insertion procedure-related associations with maximum insertion torque were recorded. The quality of most outcomes was classified as "moderate." Outcomes could not be combined in a meta-analysis because of high risk of bias, poor standardization, high heterogeneity, or inconsistency in direction of outcomes within or between studies. Adverse effects were only assessed in one study. Future studies should control publication bias, consult existing standards for conducting torque tests, and focus on transparent reporting.
    08/2013; 227(11). DOI:10.1177/0954411913495986
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    ABSTRACT: To evaluate the diagnostic performance of computed tomography angiography (CTA) and contrast-enhanced magnetic resonance angiography (CE-MRA) in detecting haemodynamically significant arterial stenosis or occlusion in patients with critical limb ischaemia (CLI) or intermittent claudication (IC). Medline and Embase were searched for studies comparing CTA or CE-MRA with digital subtraction angiography as a reference standard, including patients with CLI or IC. Outcome measures were aortotibial arterial stenosis of more than 50 % or occlusion. Methodological quality of studies was assessed using QUADAS. Out of 5,693 articles, 12 CTA and 30 CE-MRA studies were included, respectively evaluating 673 and 1,404 participants. Summary estimates of sensitivity and specificity were respectively 96 % (95 % CI, 93-98 %) and 95 % (95 % CI, 92-97 %) for CTA, and 93 % (95 % CI, 91-95 %) and 94 % (95 % CI, 93-96 %) for CE-MRA. Regression analysis showed that the prevalence of CLI in individual studies was not an independent predictor of sensitivity and specificity for either technique. Methodological quality of studies was moderate to good. CTA and CE-MRA are accurate techniques for evaluating disease severity of aortotibial arteries in patients with CLI or IC. No significant differences in the diagnostic performance of the two techniques between patients with CLI and IC were found. • Computed tomography and contrast-enhanced magnetic resonance angiography can both demonstrate arterial disease. • CTA and CE-MRA can both accurately evaluate arteries in peripheral arterial disease. • Diagnostic performances of critical limb ischaemia and intermittent claudication are not different. • Separate imaging technique of tibial arteries by CE-MRA is preferred. • CTA and CE-MRA can distinguish confidently between high-grade stenoses and occlusions.
    European Radiology 06/2013; DOI:10.1007/s00330-013-2933-8 · 4.34 Impact Factor
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    ABSTRACT: Purpose:To obtain performance values of magnetic resonance (MR) imaging for restaging locally advanced rectal cancer after neoadjuvant treatment regarding tumor staging, nodal staging, and tumor-free circumferential resection margins (CRMs).Materials and Methods:MEDLINE, EMBASE, and Cochrane databases were searched for studies regarding restaging compared with a reference standard by using the terms rectal neoplasms, MR imaging, and chemotherapy. The Quality Assessment of Diagnostic Accuracy Studies tool was used, and data on imaging criteria, histopathologic criteria, and restaging were extracted. Responders were defined as positives and nonresponders, as negatives. Mean sensitivity, mean specificity, and positive and negative likelihood ratios (LRs) were determined by using a bivariate random-effects model. A positive LR greater than 5 implied moderate results for responders.Results:Thirty-three studies evaluated 1556 patients. For tumor stage, mean sensitivity was 50.4%, mean specificity was 91.2%, positive LR was 5.76, and negative LR was 0.54. Diffusion-weighted (DW) imaging showed comparable positive LR with significantly improved sensitivity (P = .01) and negative LR (P = .04). Experienced observers showed higher sensitivity (P = .01) and lower negative LR (P = .03) compared with less experienced observers. For CRM, mean sensitivity, mean specificity, positive LR, and negative LR were 76.3%, 85.9%, 5.40, and 0.28, respectively. For nodal stage per patient, mean sensitivity, mean specificity, positive LR, and negative LR were 76.5%, 59.8%, 1.90, and 0.39, respectively; and for nodal stage on a lesion basis, these values were 90.7%, 73.0%, 3.37, and 0.13, respectively.Conclusion:MR imaging showed heterogeneous results of diagnostic performances for restaging rectal cancer after neoadjuvant treatment, but significantly better results were demonstrated when DW imaging was used or with experienced observers. MR imaging can also be used for evaluation of CRM staging, but nodal staging remains challenging.© RSNA, 2013Supplemental material:
    Radiology 06/2013; 269(1). DOI:10.1148/radiol.13122833 · 6.21 Impact Factor
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    ABSTRACT: BACKGROUND:: Tumor necrosis factor (TNF) antagonists can induce mucosal healing in patients with Crohn's disease (CD), but the effects on transmural inflammation and stenotic lesions are largely unknown. METHODS:: We performed a retrospective study in 50 patients (54% female, median age 37 yr) with CD who had undergone serial magnetic resonance imaging (MRI) examinations while receiving infliximab or adalimumab. Patients were grouped as clinical responders or nonresponders based on physician's assessment, laboratory, and endoscopic appearance. MRI scoring was performed by 2 radiologists in consensus blinded to clinical data using a validated MRI scoring system. In total, 64 lesions on MRI were identified for analysis. Analyses were performed using paired t test and Wilcoxon rank test. RESULTS:: During anti-TNF treatment, MRI inflammation scores improved in 29 of 64 lesions (45.3%), remained unchanged in 18 of 64 lesions (28.1%), or deteriorated in 17 of 64 lesions (26.6%) over time. In the anti-TNF responder group, the mean intestinal inflammation score of all lesions improved from 5.19 to 3.12 (P < 0.0001). The mean inflammation scores in stenotic lesions in anti-TNF responders also improved significantly, from 6.33 to 4.58 (P = 0.01). In contrast, the mean inflammation scores did not change significantly (5.55-5.92, P = 0.49) in nonresponders. Diagnostic accuracy of anti-TNF response on MRI was 68%. CONCLUSIONS:: Improved inflammatory activity on serial MRI scans was observed in patients with clinical response to medical therapy with anti-TNF agents in luminal CD. MRI can be used as a complementary approach to measure transmural inflammation in patients with CD and guide the optimal use of TNF antagonists in daily clinical practice.
    Inflammatory Bowel Diseases 06/2013; DOI:10.1097/MIB.0b013e3182905536 · 5.48 Impact Factor

Publication Stats

3k Citations
366.50 Total Impact Points


  • 2006–2014
    • University of Amsterdam
      • Department of Radiology
      Amsterdamo, North Holland, Netherlands
  • 2003–2014
    • Academisch Medisch Centrum Universiteit van Amsterdam
      • Department of Radiology
      Amsterdamo, North Holland, Netherlands
  • 2013
    • AMC Health
      New York, New York, United States
  • 2009–2012
    • Academic Medical Center (AMC)
      Amsterdamo, North Holland, Netherlands