Shandra Bipat

University of Amsterdam, Amsterdamo, North Holland, Netherlands

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Publications (127)403.18 Total impact

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    ABSTRACT: Purpose: To assess the reliability of magnetic resonance imaging (MRI) for evaluation of craniocaudal tumour extension by comparing the craniocaudal tumour extension on the pre-operative MRI and post-operative hysterectomy specimen in patients with early stage uterine cervical cancer. Materials and methods: After approval of the institutional review board was acquired, pre-operative MRI and hysterectomy specimen of 21 women with early stage cervical cancer were re-evaluated. The craniocaudal extension on MRI was measured separately by two experienced radiologists and compared with corresponding measurements from the hysterectomy specimen, which were re-evaluated by an experienced pathologist. Results: Median craniocaudal extension of uterine cervical cancer on MRI was slightly smaller compared to histopathology (2.1. cm vs. 2.5. cm). The median underestimation was 0.4. cm (range -0.6. cm to 2.2. cm, mean 0.4. cm, standard deviation (SD) ±0.7. cm); Pearson's correlation was 0.83 (. p<. 0.001). In two patients (9%) MRI underestimated tumour craniocaudal extension by more than 1.8. cm. Conclusion: MRI represents the histopathological craniocaudal tumour extension in the majority of patients with early stage uterine cervical cancer, but with a systematic small underestimation of the real craniocaudal tumour extension.
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    ABSTRACT: Purpose: Surveillance CT colonography (CTC) is a viable option for 6-9 mm polyps at CTC screening for colorectal cancer. We established participation and diagnostic yield of surveillance and determined overall yield of CTC screening. Material and methods: In an invitational CTC screening trial 82 of 982 participants harboured 6-9 mm polyps as the largest lesion(s) for which surveillance CTC was advised. Only participants with one or more lesion(s) ≥6 mm at surveillance CTC were offered colonoscopy (OC); 13 had undergone preliminary OC. The surveillance CTC yield was defined as the number of participants with advanced neoplasia in the 82 surveillance participants, and was added to the primary screening yield. Results: Sixty-five of 82 participants were eligible for surveillance CTC of which 56 (86.2 %) participated. Advanced neoplasia was diagnosed in 15/56 participants (26.8 %) and 9/13 (69.2 %) with preliminary OC. Total surveillance yield was 24/82 (29.3 %). No carcinomas were detected. Adding surveillance results to initial screening CTC yield significantly increased the advanced neoplasia yield per 100 CTC participants (6.1 to 8.6; p < 0.001) and per 100 invitees (2.1 to 2.9; p < 0.001). Conclusion: Surveillance CTC for 6-9 mm polyps has a substantial yield of advanced adenomas and significantly increased the CTC yield in population screening. Key points: • The participation rate in surveillance CT colonography (CTC) is 86 %. • Advanced adenoma prevalence in a 6-9 mm CTC surveillance population is high. • Surveillance CTC significantly increases the yield of population screening by CTC. • Surveillance CTC for 6-9 mm polyps is a safe strategy. • Surveillance CTC is unlikely to yield new important extracolonic findings.
    European Radiology 11/2015; DOI:10.1007/s00330-015-4081-9 · 4.01 Impact Factor
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    ABSTRACT: Objectives: Volumetric growth assessment has been proposed for predicting advanced histology at surveillance computed tomography (CT) colonography (CTC). We examined whether is it possible to predict which small (6-9 mm) polyps are likely to become advanced adenomas at surveillance by assessing volumetric growth. Methods: In an invitational population-based CTC screening trial, 93 participants were diagnosed with one or two 6-9 mm polyps as the largest lesion(s). They were offered a 3-year surveillance CTC. Participants in whom surveillance CTC showed lesion(s) of ≥6 mm were offered colonoscopy. Volumetric measurements were performed on index and surveillance CTC, and polyps were classified into growth categories according to ±30% volumetric change (>30% growth as progression, 30% growth to 30% decrease as stable, and >30% decrease as regression). Polyp growth was related to histopathology. Results: Between July 2012 and May 2014, 70 patients underwent surveillance CTC after a mean surveillance interval of 3.3 years (s.d. 0.3; range 3.0-4.6 years). In all, 33 (35%) of 95 polyps progressed, 36 (38%) remained stable, and 26 (27%) regressed, including an apparent resolution in 13 (14%) polyps. In 68 (83%) of the 82 polyps at surveillance, histopathology was obtained; 15 (47%) of 32 progressing polyps were advanced adenomas, 6 (21%) of 28 stable polyps, and none of the regressing polyps. Conclusions: The majority of 6-9 mm polyps will not progress to advanced neoplasia within 3 years. Those that do progress to advanced status can in particular be found among the lesions that increased in size on surveillance CTC.Am J Gastroenterol advance online publication, 20 October 2015; doi:10.1038/ajg.2015.340.
    The American Journal of Gastroenterology 10/2015; DOI:10.1038/ajg.2015.340 · 10.76 Impact Factor
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    ABSTRACT: Although the Vascular Quality of Life Questionnaire (VascuQol) is a widely used instrument to assess quality of life in patients with peripheral arterial disease (PAD), data on its reliability are scarce and its measurement error is unknown. The aim of this study was to determine test-retest reliability and measurement error of the Dutch version of the VascuQol in patients with intermittent claudication (IC). Patients with intermittent claudication due to PAD presenting between October 2013 and April 2014 completed the VascuQol twice, with a 1 week interval. Test-retest reliability was expressed as the intraclass correlation coefficient (ICC) with 95% confidence interval (CI), and measurement error as a standard error of measurement (SEM). Sixty-one patients completed two VascuQol questionnaires sufficiently. The ICC for the VascuQol sumscore was 0.91 (95% CI 0.86-0.95). The ICC for the different VascuQol domains ranged between 0.77 (95% CI 0.64-0.86) and 0.87 (95% CI 0.79-0.92). The SEM of the sumscore was 0.34 and ranged between 0.44 and 0.76 for the different VascuQol domains. The test-retest reliability of the Dutch version of the VascuQol is excellent, both for the sumscore and for its different domains. The VascuQol has a measurement error that is sufficiently small to allow detection of clinically relevant changes. Copyright © 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.
    European journal of vascular and endovascular surgery: the official journal of the European Society for Vascular Surgery 08/2015; 50(4). DOI:10.1016/j.ejvs.2015.07.007 · 2.49 Impact Factor
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    C A J Puylaert · J A W Tielbeek · S Bipat · J Stoker ·
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    ABSTRACT: To assess the grading of Crohn's disease activity using CT, MRI, US and scintigraphy. MEDLINE, EMBASE and Cochrane databases were searched (January 1983-March 2014) for studies evaluating CT, MRI, US and scintigraphy in grading Crohn's disease activity compared to endoscopy, biopsies or intraoperative findings. Two independent reviewers assessed the data. Three-by-three tables (none, mild, frank disease) were constructed for all studies, and estimates of accurate, over- and under-grading were calculated/summarized by fixed or random effects models. Our search yielded 9356 articles, 19 of which were included. Per-patient data showed accurate grading values for CT, MRI, US and scintigraphy of 86 % (95 % CI: 75-93 %), 84 % (95 % CI: 67-93 %), 44 % (95 % CI: 28-61 %) and 40 % (95 % CI: 16-70 %), respectively. In the per-patient analysis, CT and MRI showed similar accurate grading estimates (P = 0.8). Per-segment data showed accurate grading values for CT and scintigraphy of 87 % (95 % CI: 77-93 %) and 86 % (95 % CI: 80-91 %), respectively. MRI and US showed grading accuracies of 67-82 % and 56-75 %, respectively. CT and MRI showed comparable high accurate grading estimates in the per-patient analysis. Results for US and scintigraphy were inconsistent, and limited data were available. • CT and MRI have comparable high accuracy in grading Crohn's disease. • Data on US and scintigraphy is inconsistent and limited. • MRI is preferable over CT as it lacks ionizing radiation exposure.
    European Radiology 06/2015; 25(11). DOI:10.1007/s00330-015-3737-9 · 4.01 Impact Factor
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    ABSTRACT: The prevalence of child maltreatment in Suriname has never been subjected to a reliable assessment. The only data available include rough estimates of a range of internationally comparable indicators extrapolated from child protection and police corps statistics for offenses against children. This study aimed to provide a reliable estimate of the prevalence of all forms of child maltreatment in Suriname. One thousand three hundred and ninety-one (1,391) adolescents and young adults of different ethnicities completed a questionnaire about child maltreatment. The study sample, obtained by random probability sampling, consisted of students (ages 12 through 22) from five districts in Suriname. A significant proportion of Surinamese children experienced maltreatment. In total, 86.8% of adolescents and 95.8% of young adults reported having been exposed to at least one form of child maltreatment during their lives. Among the adolescents, 57.1% were exposed to child maltreatment in the past year. When the definition of the National Incidence Study was applied, 58.2% of adolescents and 68.8% of young adults had been exposed to at least one form of maltreatment. Among adolescents, 36.8% reported having experienced at least one form of maltreatment in the past year. The results indicate the (extremely) high lifetime and year prevalence of child maltreatment in Suriname. The serious and often lifelong consequences of such maltreatment indicate that a national approach to child abuse and neglect, including the development of a national strategic plan, a national surveillance system and changes to the state's programmatic and policy response, is urgently needed. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Child abuse & neglect 04/2015; 47. DOI:10.1016/j.chiabu.2015.03.019 · 2.34 Impact Factor
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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 · 2.37 Impact Factor
  • Sanne M. Schreuder · Rutger Lensing · Jaap Stoker · Shandra Bipat ·
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    ABSTRACT: Purpose: To determine the role of diffusion-weighted imaging (DWI) in evaluating response to chemoradiotherapy in patients with uterine cervical cancer. Materials and methods: A 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. Results: Nine 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) mm(2) /s to 1.50 × 10(-3) mm(2) /s; Δ0.62 × 10(-3) mm(2) /s) compared to partial responders (1.03 × 10(-3) mm(2) /s to 1.42 × 10(-3) mm(2) /s; Δ0.39 × 10(-3) mm(2) /s) and to nonresponders (0.87 × 10(-3) mm(2) /s to 1.18 × 10(-3) mm(2) /s; Δ0.31 × 10(-3) mm(2) /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. Conclusion: DWI can be used for monitoring treatment response after treatment, but not for the early response monitoring. J. Magn. Reson. Imaging 2015;42:572-594.
    Journal of Magnetic Resonance Imaging 10/2014; 42(3). DOI:10.1002/jmri.24784 · 3.21 Impact Factor
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    ABSTRACT: Objectives: Determine the incidence of patients at risk for contrast-induced nephropathy (CIN), the incidence of CIN and mid-term effects (renal replacement therapy/death < one month) to measure the impact of CIN in a general patient population undergoing intravenous contrast-enhanced computed tomography (CECT). Methods: We conducted a prospective study in consecutive patients undergoing intravenous CECT from October 2012 to May 2013. Data were obtained through scripted interviews and the electronic patient records. Presence of risk factors and kidney function before and after CECT and the follow-up for one month were evaluated. Results: We included 998 patients (mean age: 60 years). Estimated GFR was ≥ 60 ml/mg/1.72 m2 in 886 (88.8%) patients, 30-59 ml/mg/1.72 m2 in 108 (10.8%) patients and < 30 ml/min/1.73 m2 in 4 (0.4%) patients. We found diabetes mellitus in 137 (13.7%), anaemia in 70 (7.0%) congestive heart failure in 92 (9.2%), peripheral arterial disease in 34 (3.4%), age > 75 years in 126 (12.6%) patients and 301 (30.2%) used nephrotoxic medication. Fifty-eight (5.8%) patients were at risk for CIN; 35 (60.3%) risk patients received intravenous prophylactic hydration. Of the hydrated patients, 11 underwent follow-up within one week; of the non-hydrated patients seven underwent follow-up within one week. Two (2/58: 3.4%) patients developed CIN (increased serum creatinine ≥ 44 μmol/l or ≥ 25%); there was no difference between hydrated and non-hydrated patients (1/35:1/23). The incidence of renal replacement therapy and death within one month was zero for both. Conclusion: The number of patients at risk is low. CIN incidence is low, even in patients not receiving prophylactic hydration. No patients received renal replacement therapy or died. The impact of CIN is low. Extensive CIN prevention guidelines seem superfluous.
    The Netherlands Journal of Medicine 09/2014; 72(7):363-71. · 1.97 Impact Factor
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    ABSTRACT: Purpose: 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. Methods: A prospective, observational cohort study was conducted between May 2007 and May 2010 in patients presenting with CLI. At baseline, the optimal treatment was selected, i.e., endovascular or surgical treatment. In case of uncertainty about the preferred treatment, a multidisciplinary team (MDT) was consulted. Primary endpoints were quality of life and functional status 6 and 12 months after initial intervention, assessed by the VascuQol and AMC Linear Disability Score questionnaires, respectively. Results: In total, 113 patients were included; 86 had an endovascular intervention and 27 had surgery. During follow-up, 41 % underwent an additional ipsilateral revascularisation procedure. For the total population, and endovascular and surgery subgroups, the VascuQol sum scores improved after 6 and 12 months (p < 0.01 for all outcomes) compared with baseline. The functional status improved (p = 0.043) after 12 months compared with baseline for the total population. Functional status of the surgery subgroup improved significantly after 6 (p = 0.031) and 12 (p = 0.044) months, but not that of the endovascular subgroup. Conclusions: Overall, the strategy of performing endovascular treatment first in patients with poor condition, unfavourable anatomy for surgery, no venous material for bypass, and old age has comparable or even slightly better results compared with the BASIL trial and other cohort studies. All vascular groups should discuss whether their treatment strategy should be directed at treating CLI patients preferably endovascular first and consider implementing an MDT to optimize patient outcomes.
    CardioVascular and Interventional Radiology 08/2014; 38(3). DOI:10.1007/s00270-014-0955-5 · 2.07 Impact Factor
  • S M Schreuder · AE Scholtens · JA Reekers · S Bipat ·
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    ABSTRACT: Purpose: 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). Methods: 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. Results: 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. Conclusions: 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 · 2.07 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 · 1.57 Impact Factor
  • S I Moos · R S de Weijert · G Nagan · J Stoker · S Bipat ·
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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 contrast-enhanced 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 <60 ml/min/1.73 m(2), 94.8% were identified including all with an eGFR <45 ml/min/1.73 m(2). Conclusion: Determining eGFR based on risk factors for kidney disease is not more cost-effective than eGFR testing in all patients if the eGFR is tenable for 12 months or for 3 months.
    The Netherlands Journal of Medicine 06/2014; 72(5):271-80. · 1.97 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; 47(5). DOI:10.1016/j.ejvs.2014.02.012 · 2.49 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 · 2.37 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; 24(6). DOI:10.1007/s00330-014-3149-2 · 4.01 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; 24(5). DOI:10.1007/s00330-014-3111-3 · 4.01 Impact Factor

  • Radiotherapy and Oncology 01/2014; 111:S40-S41. DOI:10.1016/S0167-8140(15)30869-0 · 4.36 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 · 2.73 Impact Factor

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4k Citations
403.18 Total Impact Points


  • 2005-2015
    • University of Amsterdam
      • Department of Radiology
      Amsterdamo, North Holland, Netherlands
  • 2003-2014
    • Academisch Medisch Centrum Universiteit van Amsterdam
      • • Department of Radiology
      • • Academic Medical Center
      Amsterdamo, North Holland, Netherlands
  • 2013
    • AMC Health
      New York, New York, United States
  • 2009-2012
    • Academic Medical Center (AMC)
      Amsterdamo, North Holland, Netherlands