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Background: Cardiac computed tomography (CT) is increasingly used to search for cardioembolic sources of acute ischemic stroke (AIS). We assessed the association between high-risk cardioembolic sources on cardiac CT and AIS., Methods: We performed a case-control study using data from a prospective cohort including consecutive adult patients with suspected stroke who underwent cardiac CT acquired during the initial stroke imaging protocol between 2018 and 2020. Cases were patients with a final diagnosis of AIS. Controls were patients with a stroke mimic (SMi). We excluded patients with a transient ischemic attack. Diagnoses were established by an adjudication committee. Cardiac radiologists assessed the presence of structural high-risk sources of cardioembolism according to predefined criteria. We used the Firth penalized likelihood method to perform a logistic regression, adjusted for age, sex, and history of myocardial infarction to determine the association between high-risk embolic sources and AIS. For the primary analysis, we excluded patients with a history of atrial fibrillation. In a secondary analysis, patients with known atrial fibrillation were included., Results: Of 774 patients, we excluded 167 patients due to no written informed consent or the diagnosis of transient ischemic attack. Of 607 patients, 107 patients had known atrial fibrillation and were excluded from the primary analysis. Of 500 included patients, 375 had AIS (75%, median age 70, 61% male) and 125 SMi (25%, median age 69, 42% male). A high-risk cardioembolic source was found on CT in 32/375 (8.5%) patients with AIS and 0/125 (0%) patients with SMi (adjusted odds ratio, 23.8 [95% CI, 3.3-3032.5]). Cardiac thrombi were the most commonly observed abnormality, present in 23 (6.1%) patients with AIS and 0 (0%) patients with SMi., Conclusions: A high-risk source of cardioembolism was detected on cardiac CT more frequently in patients with AIS than in patients with SMi. These data substantiate the clinical relevance of cardioembolic sources detected on acute cardiac CT in patients with ischemic stroke., Competing Interests: Dr Bouma has received grants from Abbott Fund. Dr Marquering is a shareholder in inSteps. Dr Majoie has received research grants from CVON/Dutch Heart Foundation, European Commission, Health Evaluation Netherlands, Stryker Corporation, and Boehringer Ingelheim (all paid to the institution). Drs Majoie, Marquering, and Roos are shareholders of Nicolab, a company that focuses on the use of artificial intelligence for medical image analysis. Dr Coutinho reports grants from Medtronic, Siemens, AstraZeneca, and Bayer outside the submitted work (paid to the institution). Dr Coutinho has received compensation from Portola Pharmaceuticals, LLC for consultant services (paid to employer). Dr Coutinho is a shareholder of Founder. Dr Coutinho and Marquering are shareholders of TrianecT. The other authors report no conflicts of interest.

A 62-year-old recreational cyclist presented with transient loss of consciousness and common electrocardiographic findings. Despite absence of left ventricular hypertrophy, multidisciplinary evaluation and a positive family history led to the diagnosis of non-classical Fabry disease. This case emphasizes the added value of multidisciplinary analysis of nonspecific findings to diagnose a rare disease., Competing Interests: The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2024 The Authors.)

Background: Left atrial appendage (LAA) slow-flow may increase the risk of ischemic stroke. We studied LAA attenuation on cardiac computed tomography in patients with acute ischemic stroke., Methods and Results: We used data from a prospective cohort of patients with acute ischemic stroke undergoing cardiac computed tomography during the acute stroke imaging protocol. We compared characteristics, functional outcome (modified Rankin scale: higher scores indicating worse outcome), stroke recurrence and major adverse cardiovascular events after 2-year follow-up between patients with LAA thrombus (filling defect<100 Hounsfield Unit (HU)), slow-flow (filling defect ≥100 HU) and normal filling. Of 421 patients, 31 (7%) had LAA thrombus, 69 (16%) slow-flow, and 321 (76%) normal filling. Patients with thrombus or slow-flow more often had known atrial fibrillation compared with normal filling (45%, 39%, and 9%, P <0.001). Patients with thrombus had higher National Institutes of Health Stroke Scale-scores compared with slow-flow and normal filling (18 [interquartile range, 9-22], 6 [interquartile range, 3-17], and 5 [interquartile range, 2-11], P <0.001). Compared with normal filling, there was no difference with slow-flow in functional outcome (median modified Rankin scale, 3 versus 2; acOR 0.8 [95% CI, 0.5-1.4]), stroke recurrence (adjusted hazard ratio, 0.8 [95% CI, 0.3-1.9]) or major adverse cardiovascular events (adjusted hazard ratio, 1.2 [95% CI, 0.7-2.1]), while patients with thrombus had worse functional outcome (median modified Rankin scale, 6, acOR, 3.3 [95% CI, 1.5-7.4]). In cryptogenic stroke patients (n=156) slow-flow was associated with stroke recurrence (27% versus 6%, aHR, 4.1 [95% CI, 1.1-15.7])., Conclusions: Patients with slow-flow had similar characteristics to patients with thrombus, but had less severe strokes. Slow-flow was not significantly associated with functional outcome or major adverse cardiovascular events, but was associated with recurrent stroke in patients with cryptogenic stroke.

Background: Cardiac computed tomography (CT) acquired during the initial acute stroke imaging protocol (acute cardiac CT) is increasingly used to screen for cardioembolism, but information on the long-term clinical implications of its findings is lacking., Methods and Results: We performed a prospective, single-center cohort study in which consecutive patients with ischemic stroke underwent ECG-gated acute cardiac CT and were followed up for 2 years. The primary outcome was functional outcome assessed using the modified Rankin Scale. Secondary outcomes were death and occurrence of major adverse cardiovascular events (composite of recurrent ischemic stroke, myocardial infarction, and cardiovascular death). We compared patients with and without a high-risk structural source of embolism on acute cardiac CT. Of 452 included patients, 55 (12.2%) had a high-risk source of embolism, predominantly cardiac thrombi (38 patients) and signs of endocarditis (8 patients). Follow-up at 2 years was complete for 430 (95.1%) patients. Patients with a high-risk source of embolism had a worse functional outcome (median modified Rankin Scale, 6 [IQR, 2-6] versus 2 [IQR, 1-5]; adjusted common odds ratio, 2.92 [95% CI, 1.62-5.25]), increased mortality rate (52.7% versus 23.7%; adjusted hazard ratio [HR], 3.28 [95% CI, 1.94-5.52]), and major adverse cardiovascular events (38.9% versus 17.5%; adjusted HR, 3.20 [95% CI, 1.80-5.69]). A high-risk source of embolism was not associated with recurrent ischemic stroke (11.1% versus 9.6%; adjusted HR, 1.30 [95% CI, 0.49-3.44])., Conclusions: Structural high-risk sources of embolism on acute cardiac CT in patients with ischemic stroke were associated with poor long-term functional outcome and occurrence of major adverse cardiovascular events but not with recurrent stroke.

Objective: Longitudinal consequences and potential interactions of COVID-19 and elite-level sports and exercise are unclear. Therefore, we determined the long-term detrimental cardiac effects of the interaction between SARS-CoV-2 infection and the highest level of sports and exercise., Methods: This prospective controlled study included elite athletes from the Evaluation of Lifetime participation in Intensive Top-level sports and Exercise cohort. Athletes infected with SARS-CoV-2were offered structured, additional cardiovascular screenings, including cardiovascular MRI (CMR). We compared ventricular volumes and function, late gadolinium enhancement (LGE) and T1 relaxation times, between infected and non-infected elite athletes, and collected follow-up data on cardiac adverse events, ventricular arrhythmia burden and the cessation of sports careers., Results: We included 259 elite athletes (mean age 26±5 years; 40% women), of whom 123 were infected (9% cardiovascular symptoms) and 136 were controls. We found no differences in function and volumetric CMR parameters. Four infected athletes (3%) demonstrated LGE (one reversible), compared with none of the controls. During the 26.7 (±5.8) months follow-up, all four athletes resumed elite-level sports, without an increase in ventricular arrhythmias or adverse cardiac remodelling. None of the infected athletes reported new cardiac symptoms or events. The majority (n=118; 96%) still participated in elite-level sports; no sports careers were terminated due to SARS-CoV-2., Conclusions: This prospective study demonstrates the safety of resuming elite-level sports after SARS-CoV-2 infection. The medium-term risks associated with SARS-CoV-2 infection and elite-level sports appear low, as the resumption of elite sports did not lead to detrimental cardiac effects or increases in clinical events, even in the four elite athletes with SARS-CoV-2 associated myocardial involvement., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Cardiac thrombi are an important cause of ischemic stroke but are infrequently detected on cardiac imaging. We hypothesized that this might be explained by early dissolution of these cardiac thrombi after stroke occurrence., Methods: We performed a single-center observational pilot study between November 2019 and November 2020, embedded in the larger "Mind-the-Heart" study. We included patients with AIS and a cardiac thrombus in the left atrium or ventricle (filling defect <100 Hounsfield Units) diagnosed on cardiac CT that was acquired during the initial stroke imaging protocol. We repeated cardiac CT within one week to determine if the thrombus had dissolved., Results: Five patients (four men, median age 52 years, three with atrial fibrillation and one with anticoagulation therapy at baseline) were included. Median time from symptom onset to first cardiac CT was 383 (range 42-852) minutes and median time from first to second cardiac CT was three days (range 1-7). Two patients received intravenous thrombolysis (IVT). In total, six thrombi were seen on initial CT imaging (one in the left ventricle, four in the left atrial appendage, one in the left atrium). The left atrium thrombus and one left atrial appendage thrombus had dissolved on follow-up cardiac CT, one of which was in a patient with IVT treatment., Conclusion: This pilot study illustrates that cardiac thrombi can dissolve within days of stroke occurrence both with and without IVT treatment., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: CBLMM has received research grants from CVON/Dutch Heart Foundation, European Commission, TWIN Foundation, Healthcare Evaluation Netherlands and Stryker (paid to institution). CBLMM, HAM and YBWEMR are shareholders of Nicolab, a company that focuses on the use of artificial intelligence for medical image analysis. JMC reports grants from Medtronic, Boehringer Ingelheim, and Bayer outside the submitted work (paid to institution). JMC and HAM are shareholder of TrianecT. The other authors have no financial conflicts of interest., (© 2023 The Authors. Published by Elsevier Ltd.)

Background: Cardiac CT acquired during the acute stroke imaging protocol is an emerging alternative to transthoracic echocardiography (TTE) to screen for sources of cardioembolism. Currently, its diagnostic accuracy to detect patent foramen ovale (PFO) is unclear., Methods: This was a substudy of Mind the Heart, a prospective cohort in which consecutive adult patients with acute ischemic stroke underwent prospective ECG-gated cardiac CT during the initial stroke imaging protocol. Patients also underwent TTE. We included patients < 60 years who underwent TTE with agitated saline contrast (cTTE) and assessed sensitivity, specificity, negative and positive predictive value of cardiac CT for the detection of PFO using cTTE as the reference standard., Results: Of 452 patients in Mind the Heart, 92 were younger than 60 years. Of these, 59 (64%) patients underwent both cardiac CT and cTTE and were included. Median age was 54 (IQR 49-57) years and 41/59 (70%) were male. Cardiac CT detected a PFO in 5/59 (8%) patients, 3 of which were confirmed on cTTE. cTTE detected a PFO in 12/59 (20%) patients. Sensitivity and specificity of cardiac CT were 25% (95% CI 5-57%) and 96% (95% CI 85-99%), respectively. Positive and negative predictive values were 59% (95% CI 14-95) and 84% (95% CI 71-92)., Conclusion: Prospective ECG-gated cardiac CT acquired during the acute stroke imaging protocol does not appear to be a suitable screening method for PFO due to its low sensitivity. Our data suggest that if cardiac CT is used as a first-line screening method for cardioembolism, additional echocardiography remains indicated in young patients with cryptogenic stroke, in whom PFO detection would have therapeutic consequences. These results need to be confirmed in larger cohorts., (© 2023. The Author(s).)

Background: Cardiac thrombi are a major risk factor for ischemic stroke, but are rarely diagnosed in the acute phase. We examined characteristics and functional outcome of patients with ischemic stroke and a concomitant cardiac thrombus detected on cardiac CT performed in the acute phase., Patients and Methods: We used data from "Mind the Heart," a prospective cohort study in which consecutive adult patients with acute ischemic stroke underwent prospective ECG-gated cardiac CT during their acute stroke imaging protocol. We compared characteristics, functional outcome (modified Rankin scale) and stroke recurrence rate at 90 days of patients with a cardiac thrombus on CT (defined as filling defect <100 Hounsfield Units) to those without a cardiac thrombus., Results: Among 452 included patients, cardiac CT detected 41 thrombi in 38 (8%) patients. Thrombi were most often located in the left atrial appendage (31/38 [82%]). Patients with a cardiac thrombus more frequently had intracranial occlusions in multiple vascular territories (5% vs 0.5%, p  = 0.04) and a higher baseline NIHSS score (17 [IQR 6-22] vs 5 [IQR 2-3], p  < 0.001) compared to patients without a cardiac thrombus. In 13/38 (34%) patients with a cardiac thrombus, no atrial fibrillation was detected. A cardiac thrombus was associated with worse functional outcome (adjusted common odds ratio 3.18 95%CI 1.68-6.00). Recurrence rate was not significantly different (8% vs 4%, aOR 1.50 (0.39-5.82)., Discussion and Conclusion: Cardiac CT detected a cardiac thrombus in one in every 12 patients with acute ischemic stroke, and these patients had more severe deficits, multivessel occlusions, and a worse functional outcome., Competing Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: CBLMM has received research grants from CVON/Dutch Heart Foundation, European Commission, TWIN Foundation Dutch Health Evaluation program and Stryker (paid to institution). CBLMM, HAM and YBWEMR are shareholders of Nico.lab, a company that focuses on the use of artificial intelligence for medical image analysis. JMC reports grants from Medtronic, Boehringer Ingelheim, and Bayer outside the submitted work. (paid to institution). The other authors have no financial conflicts of interest., (© European Stroke Organisation 2022.)

Introduction: The cardiovascular benefits of physical exercise are well-known. However, vigorous exercise has also been associated with adverse cardiac effects. To improve our understanding of cardiovascular adaptation to exercise versus maladaptation and pathology, the limits of adaptation should be firmly established using state-of-the-art diagnostic modalities. We therefore initiated the Evaluation of Lifetime participation in Intensive Top-level sports and Exercise (ELITE) cohort to investigate the longitudinal (beneficial and pathological) cardiovascular effects of intensive elite sports and exercise., Methods and Analysis: ELITE is a prospective, multicentre, longitudinal cohort study. Elite athletes, from the age of sixteen, are recruited in The Netherlands. The primary objective is to determine the association between elite sports and exercise-induced cardiac remodelling, cardiac pathology, and health benefits over time. Secondary objectives include determining and identifying genetic profiles of elite athletes, and how these are associated with cardiac indices. ELITE will collect data from consultations, electrocardiography, echocardiography and cardiac magnetic resonance imaging, and training- and injury data. ELITE will also collect blood for biobanking and cardiogenetics. Follow-up will take place at intervals of two to five years, and after the elite athletes' professional careers have ended. In addition, a subcohort of ELITE has been established to investigate cardiac sequelae following infections associated with myocardial involvement, including SARS-CoV-2. ELITE is a prospective observational study; therefore, analyses will be primarily explorative., Ethics and Dissemination: This study has been approved by the Medical Ethics Review Board of the Amsterdam University Medical Centers (NL71682.018.19). The results of the study will be disseminated by publication in peer-reviewed journals (Netherlands Trial Register number: NL9328)., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Objectives: Guidelines recommend echocardiography to screen for structural sources of cardioembolism in patients with ischemic stroke. Cardiac CT is a promising alternative as a first-line screening method. We aimed to determine whether cardiac CT, acquired during the initial stroke imaging protocol, has a higher yield for detecting high-risk cardioaortic sources of embolism than transthoracic echocardiography (TTE)., Methods: We performed a prospective, single-center, observational cohort study and included consecutive adult patients with acute ischemic stroke who underwent ECG-gated cardiac CT during the initial stroke imaging protocol. Patients also underwent the routine stroke workup, including TTE. The main outcome was the proportion of patients with a predefined high-risk cardioaortic source of embolism on cardiac CT vs TTE in patients undergoing both investigations., Results: Between May 2018 and November 2020, 774 patients with a suspected ischemic stroke underwent hyperacute cardiac CT. We excluded 228 patients with a diagnosis other than ischemic stroke and 94 because they did not provide informed consent. Therefore, 452 patients (59.3% male, median age 72) were included. The median additional scan time of cardiac CT was 6 (interquartile range 5-7) minutes with poor scan quality in only 3%. In total, 350 of the 452 patients (77.4%) underwent TTE, 99 of whom were performed in an outpatient setting. Reasons for not undergoing TTE were death (33, 7.3%) and TTE being too burdensome to perform in the outpatient setting (69, 15.3%). A high-risk cardioaortic source of embolism was detected in 40 of the 350 patients (11.4%) on CT, compared with 17 of the 350 (4.9%) on TTE (odds ratio 5.60, 95% CI 2.28-16.33). Cardiac thrombus was the most frequent finding (7.1% vs 0.6%). The diagnostic yield of cardiac CT in the full study population was 55 of the 452 (12.2%). Among the 175 patients with cryptogenic stroke after the routine workup, cardiac CT identified a cause of the stroke in 11 (6.3%)., Discussion: Cardiac CT acquired in the acute phase of ischemic stroke is technically feasible and has a superior diagnostic yield compared with TTE for the detection of high-risk sources of embolism. Cardiac CT may be considered as an alternative to TTE to screen for cardioembolism., (© 2022 American Academy of Neurology.)

Objectives: Computed tomography angiography (CTA) is performed routinely in the work-up for transcatheter aortic valve implantation (TAVI), and could potentially replace invasive coronary angiography (ICA) to rule out left main (LM) and proximal coronary stenosis. The objectives were to assess the diagnostic yield and accuracy of pre-TAVI CTA to detect LM and proximal coronary stenosis of ≥ 50% and ≥ 70% diameter stenosis (DS)., Methods: The DEPICT CTA database consists of individual patient data from four studies with a retrospective design that analyzed the diagnostic accuracy of pre-TAVI CTA to detect coronary stenosis, as compared with ICA. Pooled data were used to assess diagnostic accuracy to detect coronary stenosis in the left main and the three proximal coronary segments on a per-patient and a per-segment level. We included 1060 patients (mean age: 81.5 years, 42.7% male)., Results: On ICA, the prevalence of proximal stenosis was 29.0% (≥ 50% DS) and 15.7% (≥ 70% DS). Pre-TAVI CTA ruled out ≥ 50% DS in 51.6% of patients with a sensitivity of 96.4%, specificity of 71.2%, PPV of 57.7%, and NPV of 98.0%. For ≥ 70% DS, pre-TAVI CTA ruled out stenosis in 70.0% of patients with a sensitivity of 96.7%, specificity of 87.5%, PPV of 66.9%, and NPV of 99.0%., Conclusion: CTA provides high diagnostic accuracy to rule out LM and proximal coronary stenosis in patients undergoing work-up for TAVI. Clinical application of CTA as a gatekeeper for ICA would reduce the need for ICA in 52% or 70% of patients, using a threshold of ≥ 50% or ≥ 70% DS, respectively., Key Points: • Clinical application of CTA as a gatekeeper for ICA would reduce the need for ICA in 52% or 70% of TAVI patients, using a threshold of ≥ 50% or ≥ 70% diameter stenosis. • The diagnostic accuracy of CTA to exclude proximal coronary stenosis in these patients is high, with a sensitivity of 96.4% and NPV of 98.0% for a threshold of ≥ 50%, and a sensitivity of 96.7% and NPV of 99.0% for a threshold of ≥ 70% diameter stenosis. • Atrial fibrillation and heart rate did not significantly affect sensitivity and NPV. However, a heart rate of < 70 b/min during CTA was associated with a significantly improved specificity and PPV., (© 2021. The Author(s).)

To assess the need for additional invasive coronary angiography (CAG) after initial computed tomography coronary angiography (CTCA) in patients awaiting non-coronary cardiac surgery and in patients with cardiomyopathy, heart failure or ventricular arrhythmias, and to determine differences between patients that were referred to initial CTCA or direct CAG, consecutive patients were included between August 2017 and January 2020 and categorized as those referred to initial CTCA (conform protocol), and to direct CAG (non-conform protocol). Out of a total of 415 patients, 78.8% (327 patients, mean age: 57.9 years, 67.3% male) were referred to initial CTCA, of whom 260 patients (79.5%) had no obstructive lesions (<50% DS). A total of 55 patients (16.8%) underwent additional CAG after initial CTCA, which showed coronary lesions of >50% DS in 21 patients (6.3% of 327). Eighty-eight patients (mean age: 66.0 years, 59.1% male) were directly referred to CAG (non-conform protocol). These patients were older and had more cardiovascular risk factors compared to patients that underwent initial CTCA (conform protocol), and coronary lesions of >50% DS were detected in 16 patients (17.2%). Revascularization procedures were infrequently performed in both groups: initial CTCA (3.0%), direct CAG (3.4%). The use of CTCA as a gatekeeper CAG in the diagnostic work-up of non-coronary cardiac surgery, cardiomyopathy, heart failure and ventricular arrhythmias is feasible, and only 17% of these patients required additional CAG after initial CTCA. Therefore, CTCA should be considered as the initial imaging modality to rule out CAD in these patients.

Rationale: About one-third of ischaemic strokes are caused by cardioembolism, and a substantial proportion of cryptogenic strokes likely also originate from the heart or aortic arch. Early determination of aetiology is important to optimise management. Computed Tomography-angiography of the heart is emerging as an alternative to echocardiography to detect cardio-aortic sources of embolism in stroke patients, but its diagnostic yield in acute ischaemic stroke has not been thoroughly assessed. Hypothesis: We hypothesise that electrocardiography-gated computed tomography-angiography of the heart and aortic arch, acquired in the acute phase in patients with ischaemic stroke, has a higher diagnostic yield than transthoracic echocardiography as a first-line screening method for detection of cardio-aortic sources of embolism., Methods and Design: Mind the Heart is a single-centre prospective observational cohort study. We will include consecutive adult patients with acute ischaemic stroke who are potentially eligible for reperfusion therapy. Patients undergo non-electrocardiography-gated computed tomography-angiography of the aortic arch, cervical and intracranial arteries, directly followed by prospective sequential electrocardiography-gated cardiac computed tomography-angiography. Routine work-up for cardioembolism including 12-leads electrocardiography, Holter electrocardiography and transthoracic echocardiography is performed as soon as possible. The primary endpoint is the proportion of patients with a predefined high-risk cardio-aortic source of embolism on computed tomography-angiography versus transthoracic echocardiography in patients who underwent both investigations. Based on an expected 5% additional yield of computed tomography-angiography, a sample size of 450 patients is required., Conclusions: The Mind the Heart study will generate a reliable estimate of the diagnostic yield of echocardiography-gated cardio-aortic computed tomography-angiography performed in the acute phase of ischaemic stroke., Competing Interests: Declaration of conflicting interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: CBLMM has received research grants from CVON/Dutch Heart Foundation, European Commission, TWIN Foundation Dutch Health Evaluation program and Stryker (paid to institution). CBLMM, HAM and YBWEMR are shareholders of Nico.lab, a company that focuses on the use of artificial intelligence for medical image analysis. JMC reports grants from Medtronic. The other authors have no financial conflicts of interest., (© European Stroke Organisation 2020.)

Objectives: Irreversible electroporation (IRE) is an ablative therapy with a low side-effect profile in prostate cancer. The objective was: 1) To compare the volumetric IRE ablation zone on grey-scale transrectal ultrasound (TRUS), contrast-enhanced ultrasound (CEUS) and multiparametric MRI (mpMRI) with histopathology findings; 2) To determine a reliable imaging modality to visualize the IRE ablation effects accurately., Methods: A prospective phase I-II study was performed in 16 patients scheduled for radical prostatectomy (RP). IRE of the prostate was performed 4 weeks before RP. Prior to, and 4 weeks after the IRE treatment, imaging was performed by TRUS, CEUS, and mpMRI. 3D-analysis of the ablation volumes on imaging and on H&E-stained whole-mount sections was performed. The volumes were compared and the correlation was calculated., Results: Evaluation of the imaging demonstrated that with T2-weighted MRI, dynamic contrast enhanced (DCE) MRI, and CEUS, effects of IRE are visible. T2MRI and CEUS closely match the volumes on histopathology (Pearson correlation r = 0.88 resp. 0.80). However, IRE is not visible with TRUS., Conclusions: mpMRI and CEUS are appropriate for assessing IRE effects and are the most feasible imaging modalities to visualize IRE ablation zone. The imaging is concordant with results of histopathological examination., Key Points: • mpMRI and contrast-enhanced ultrasound are appropriate imaging modalities for assessing IRE effects • mpMRI and CEUS are the most feasible imaging modalities to visualize IRE ablation zone • The imaging is concordant with results of histopathological examination after IRE • Grey-scale US is insufficient for assessing IRE ablations.

Background: Combining reirradiation (reRT) and hyperthermia (HT) has shown high therapeutic value for patients with locoregional recurrent breast cancer (LR). However, additional toxicity of reirradiation (e.g., rib fractures) may occur. The aim of this study is to determine the impact of potential risk factors on the occurrence of rib fractures., Patients and Methods: From 1982-2005, 234 patients were treated with adjuvant reRT + HT after surgery for LR. ReRT consisted typically of 8 fractions of  4 Gy twice a week, or 12 fractions of  3 Gy four times a week. A total of 118 patients were irradiated with abutted photon and electron fields. In all, 60 patients were irradiated using either one or alternating combinations of abutted AP electron fields. Hyperthermia was given once or twice a week., Results: The 5-year infield local control (LC) rate was 70 %. Rib fractures were detected in 16 of 234 patients (actuarial risk: 7 % at 5 years). All rib fractures occurred in patients treated with a combination of photon and abutted electron fields (p = 0.000); in 15 of 16 patients fractures were located in the abutment regions. The other significant predictive factors for rib fractures were a higher fraction dose (p = 0.040), large RT fields, and treatment before the year 2000., Discussion and Conclusion: ReRT + HT results in long-term LC. The majority of rib fractures were located in the photon/electron abutment area, emphasizing the disadvantage of field overlap. Large abutted photon/electron fields combined with 4 Gy fractions increase the number of rib fractures in this study group. However, as these factors were highly correlated no relative importance of the individual factors could be estimated. Increasing the number of HT sessions a week does not increase the risk of rib fractures.

Objectives: To compare the diagnostic accuracy of conditional computed tomography (CT), i.e. CT when initial ultrasound findings are negative or inconclusive, and immediate CT for patients with suspected appendicitis., Methods: Data were collected within a prospective diagnostic accuracy study on imaging in adults with acute abdominal pain. All patients underwent ultrasound and CT, read by different observers who were blinded from the other modality. Only patients with clinical suspicion of appendicitis were included. An expert panel assigned a final diagnosis to each patient after 6 months of follow-up (clinical reference standard)., Results: A total of 422 patients were included with final diagnosis appendicitis in 251 (60 %). For 199 patients (47 %), ultrasound findings were inconclusive or negative. Conditional CT imaging correctly identified 241 of 251 (96 %) appendicitis cases (95 %CI, 92 % to 98 %), versus 238 (95 %) with immediate CT (95 %CI, 91 % to 97 %). The specificity of conditional CT imaging was lower: 77 % (95 %CI, 70 % to 83 %) versus 87 % for immediate CT (95 %CI, 81 % to 91 %)., Conclusion: A conditional CT strategy correctly identifies as many patients with appendicitis as an immediate CT strategy, and can halve the number of CTs needed. However, conditional CT imaging results in more false positives., Key Points: • Conditional CT (CT after negative/inconclusive ultrasound findings) can be used for suspected appendicitis. • Half the number of CT examinations is needed with a conditional strategy. • Conditional CT correctly identifies as many patients with appendicitis as immediate CT. • Conditional imaging results in more false positive appendicitis cases.

Objective: To compare the diagnostic accuracy of conditional CT strategy, i.e. CT if ultrasound findings are negative or inconclusive, with immediate CT strategy for patients with suspected appendicitis., Design: Subanalysis of a prospective multicenter diagnostic accuracy study., Method: Only data of patients with signs of appendicitis based on medical history, physical examination, and laboratory tests were analyzed. All patients underwent both ultrasound and CT. Images of each were read by different observers who were blinded to the results of the other imaging modality. The observer then selected the most likely diagnosis. These diagnoses were compared with the reference standard, i.e. final diagnoses as assigned by an expert panel based on all available data and at least 6 months of follow-up., Results: A total of 422 patients with suspected appendicitis were included. In 251 patients the final diagnosis was acute appendicitis (59%). In 199 patients (47%), ultrasound findings were inconclusive or negative. Use of conditional CT strategy resulted in correctly identified number of correctly identified patients with appendicitis, i.e. 96% (95% CI 93-98), versus 95% identified by immediate CT (95% CI 91-97). However, conditional CT strategy resulted in more false positive diagnoses compared with immediate CT (39 versus 22), had an accompanying lower specificity of 77% (95% CI 70-83) versus 87% (95% CI 81-91), and a lower positive predictive value of 86% (95% CI 81-90) versus 92% (95% CI 87-95)., Conclusion: Use of a conditional CT strategy results in exactly the same number of patients with correctly identified acute appendicitis while halving the number of CTs needed. However, conditional strategy results in more false positive diagnoses.

Objective: The purpose of this study was to evaluate the added value of plain radiographs on top of clinical assessment in unselected patients presenting with acute abdominal pain at the emergency department (ED)., Methods: In a multicenter prospective trial, patients with abdominal pain more than 2 hours and less than 5 days presented at the ED were evaluated clinically, and a diagnosis was made by the treating physician. Subsequently, all patients underwent supine abdominal and upright chest radiographs, after which the diagnosis was reassessed by the treating physician. A final (reference) diagnosis was assigned by an expert panel. The number of changes in the primary diagnosis, as well as the accuracy of these changes, was calculated. Changes in the level of confidence were evaluated for unchanged diagnoses., Results: Between March 2005 and November 2006, 1021 patients, 55% female, mean age 47 years (range, 19-94 years), were included. In 117 of 1021 patients, the diagnosis changed after plain radiographs, and this change was correct in 39 patients (22% of changed diagnoses and 4% of total study population). Overall, the clinical diagnosis was correct in 502 (49%) patients. The diagnosis after evaluation of the radiographs was correct in 514 (50%) patients, a nonsignificant difference (P = .14). In 65% of patients with unchanged diagnosis before and after plain radiography, the level of confidence of that diagnosis did not change either., Conclusion: The added value of plain radiographs is too limited to advocate their routine use in the diagnostic workup of patients with acute abdominal pain, because few diagnoses change and the level of confidence were mostly not affected., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Objectives: Head-to-head comparison of ultrasound and CT accuracy in common diagnoses causing acute abdominal pain., Materials and Methods: Consecutive patients with abdominal pain for >2 h and <5 days referred for imaging underwent both US and CT by different radiologists/radiological residents. An expert panel assigned a final diagnosis. Ultrasound and CT sensitivity and predictive values were calculated for frequent final diagnoses. Effect of patient characteristics and observer experience on ultrasound sensitivity was studied., Results: Frequent final diagnoses in the 1,021 patients (mean age 47; 55% female) were appendicitis (284; 28%), diverticulitis (118; 12%) and cholecystitis (52; 5%). The sensitivity of CT in detecting appendicitis and diverticulitis was significantly higher than that of ultrasound: 94% versus 76% (p < 0.01) and 81% versus 61% (p = 0.048), respectively. For cholecystitis, the sensitivity of both was 73% (p = 1.00). Positive predictive values did not differ significantly between ultrasound and CT for these conditions. Ultrasound sensitivity in detecting appendicitis and diverticulitis was not significantly negatively affected by patient characteristics or reader experience., Conclusion: CT misses fewer cases than ultrasound, but both ultrasound and CT can reliably detect common diagnoses causing acute abdominal pain. Ultrasound sensitivity was largely not influenced by patient characteristics and reader experience.

Background: In patients with clinically suspected appendicitis, imaging is needed to substantiate the clinical diagnosis. Imaging accuracy of ultrasonography (US) is suboptimal, while the most accurate technique (CT) is associated with cancer related deaths through exposure to ionizing radiation. MRI is a potential replacement, without associated ionizing radiation and no need for contrast medium administration. If MRI is proven to be sufficiently accurate, it could be introduced in the diagnostic pathway of patients with suspected appendicitis, increasing diagnostic accuracy and improving clinical outcomes, without the risk of radiation induced cancer or iodinated contrast medium-related drawbacks. The multicenter OPTIMAP study was designed to estimate the diagnostic accuracy of MRI in patients with suspected acute appendicitis in the general population., Methods/design: Eligible for this study are consecutive patients presenting with clinically suspected appendicitis at the emergency department in six centers. All patients will undergo imaging according to the Dutch guideline for acute appendicitis: initial ultrasonography in all and subsequent CT whenever US does not confirm acute appendicitis. Then MRI is performed in all patients, but the results are not used for patient management. A final diagnosis assigned by an expert panel, based on all available information including 3-months follow-up, except MRI findings, is used as the reference standard in estimating accuracy. We will calculate the sensitivity, specificity, predictive values and inter-observer agreement of MRI, and aim to include 230 patients. Patient acceptance and total imaging costs will also be evaluated., Discussion: If MRI is found to be sufficiently accurate, it could replace CT in some or all patients. This will limit or obviate the ionizing radiation exposure associated risk of cancer induction and contrast medium induced nephropathy with CT, preventing the burden and the direct and indirect costs associated with treatment. Based on the high intrinsic contrast resolution of MRI, one might envision higher accuracy rates for MRI than for CT. If so, MRI could further decrease the number of unnecessary appendectomies and the number of missed appendicitis cases., Trial Registration: NTR2148.

Objectives: To identify and evaluate profiles of US and CT features associated with acute appendicitis., Methods: Consecutive patients presenting with acute abdominal pain at the emergency department were invited to participate in this study. All patients underwent US and CT. Imaging features known to be associated with appendicitis, and an imaging diagnosis were prospectively recorded by two independent radiologists. A final diagnosis was assigned after 6 months. Associations between appendiceal imaging features and a final diagnosis of appendicitis were evaluated with logistic regression analysis., Results: Appendicitis was assigned to 284 of 942 evaluated patients (30%). All evaluated features were associated with appendicitis. Imaging profiles were created after multivariable logistic regression analysis. Of 147 patients with a thickened appendix, local transducer tenderness and peri-appendiceal fat infiltration on US, 139 (95%) had appendicitis. On CT, 119 patients in whom the appendix was completely visualised, thickened, with peri-appendiceal fat infiltration and appendiceal enhancement, 114 had a final diagnosis of appendicitis (96%). When at least two of these essential features were present on US or CT, sensitivity was 92% (95% CI 89-96%) and 96% (95% CI 93-98%), respectively., Conclusion: Most patients with appendicitis can be categorised within a few imaging profiles on US and CT. When two of the essential features are present the diagnosis of appendicitis can be made accurately.

Purpose: The aim of this study was to identify patients in whom the clinical diagnosis of diverticulitis can be made with a high certainty, distinguishing them from patients requiring imaging., Methods: We prospectively recorded clinical features in patients with acute abdominal pain presenting at the emergency department, before they underwent imaging. We identified features significantly associated with a final diagnosis of acute diverticulitis using multivariate logistic regression analysis and developed a decision rule based on these features. We evaluated the performance of the rule in identifying patients with a high probability of having diverticulitis., Results: In total, 112 of the 1021 patients (11%) had a final diagnosis of diverticulitis. Of the 126 patients with clinically suspected diverticulitis, 80 had a final diagnosis of diverticulitis. In 32 patients with diverticulitis as their final diagnosis, another clinical diagnosis was made. A decision rule was based on the 3 strongest clinical features: direct tenderness only in the left lower quadrant, the absence of vomiting, and a C-reactive protein >50 mg/L. Of the 126 clinically suspected patients, 30 patients had all 3 features (24%), of whom 29 had a final diagnosis of acute diverticulitis (97%; 95% CI: 83%-99%). Of the 96 patients without all 3 features, 45 (47%) did not have diverticulitis., Conclusion: In a quarter of patients with suspected diverticulitis, the diagnosis can be made clinically based on a combination of direct tenderness only in the left lower quadrant, the absence of vomiting, and an elevated C-reactive protein. In patients without these features, imaging is required to reach adequate diagnostic accuracy.

Unlabelled: Acute abdominal pain may be caused by a myriad of diagnoses, including acute appendicitis, diverticulitis, and cholecystitis. Imaging plays an important role in the treatment management of patients because clinical evaluation results can be inaccurate. Performing computed tomography (CT) is most important because it facilitates an accurate and reproducible diagnosis in urgent conditions. Also, CT findings have been demonstrated to have a marked effect on the management of acute abdominal pain. The cost-effectiveness of CT in the setting of acute appendicitis was studied, and CT proved to be cost-effective. CT can therefore be considered the primary technique for the diagnosis of acute abdominal pain, except in patients clinically suspected of having acute cholecystitis. In these patients, ultrasonography (US) is the primary imaging technique of choice. When costs and ionizing radiation exposure are primary concerns, a possible strategy is to perform US as the initial technique in all patients with acute abdominal pain, with CT performed in all cases of nondiagnostic US. The use of conventional radiography has been surpassed; this examination has only a possible role in the setting of bowel obstruction. However, CT is more accurate and more informative in this setting as well. In cases of bowel perforation, CT is the most sensitive technique for depicting free intraperitoneal air and is valuable for determining the cause of the perforation. Imaging is less useful in cases of bowel ischemia, although some CT signs are highly specific. Magnetic resonance (MR) imaging is a promising alternative to CT in the evaluation of acute abdominal pain and does not involve the use of ionizing radiation exposure. However, data on the use of MR imaging for this indication are still sparse., Supplemental Material: http://radiology.rsna.org/content/253/1/31/suppl/DC1.

Objectives: The objective was to evaluate the diagnostic accuracy of clinical features and laboratory test results in detecting acute appendicitis., Methods: Clinical features and laboratory test results were prospectively recorded in a consecutive series of 1,101 patients presenting with abdominal pain at the emergency department (ED) in six hospitals. Likelihood ratios (LRs) and the areas under the receiver operating characteristic curve (AUC) were calculated for the individual features. Variants of clinical presentation, based on different combinations of clinical features, were investigated and the accuracies of combinations of clinical features were evaluated., Results: The discriminative power (AUC) of the individual features in patients with suspected appendicitis ranged from 0.50 to 0.65. For five of the 23 predictor sets, the accuracy for appendicitis was more than 85%. This accuracy was only found in male patients. The relative frequency of these predictor sets ranged from 2% to 13% of patients with suspected appendicitis. A combination of the clinical features migration of pain to the right lower quadrant (RLQ), and direct tenderness in the RLQ, was present in only 28% (120/422) of clinically suspected patients, of whom no more than 85 patients had appendicitis (71%). A "classical" presentation (combination of migration of pain to the RLQ, tenderness in the RLQ, and rigidity) occurred in only 6% (25/422) of patients with suspected appendicitis and yielded an accuracy of 100% in males but only 46% in females., Conclusions: The discriminative power (AUC) of individual clinical features and laboratory test results for appendicitis was weak in patients with suspected appendicitis. Combinations of clinical features and laboratory tests with high diagnostic accuracy are relatively infrequent in patients with suspected appendicitis., ((c) 2009 by the Society for Academic Emergency Medicine)

Objective: To identify an optimal imaging strategy for the accurate detection of urgent conditions in patients with acute abdominal pain., Design: Fully paired multicentre diagnostic accuracy study with prospective data collection., Setting: Emergency departments of two university hospitals and four large teaching hospitals in the Netherlands., Participants: 1021 patients with non-traumatic abdominal pain of >2 hours' and <5 days' duration. Exclusion criteria were discharge from the emergency department with no imaging considered warranted by the treating physician, pregnancy, and haemorrhagic shock., Intervention: All patients had plain radiographs (upright chest and supine abdominal), ultrasonography, and computed tomography (CT) after clinical and laboratory examination. A panel of experienced physicians assigned a final diagnosis after six months and classified the condition as urgent or non-urgent., Main Outcome Measures: Sensitivity and specificity for urgent conditions, percentage of missed cases and false positives, and exposure to radiation for single imaging strategies, conditional imaging strategies (CT after initial ultrasonography), and strategies driven by body mass index and age or by location of pain., Results: 661 (65%) patients had a final diagnosis classified as urgent. The initial clinical diagnosis resulted in many false positive urgent diagnoses, which were significantly reduced after ultrasonography or CT. CT detected more urgent diagnoses than did ultrasonography: sensitivity was 89% (95% confidence interval 87% to 92%) for CT and 70% (67% to 74%) for ultrasonography (P<0.001). A conditional strategy with CT only after negative or inconclusive ultrasonography yielded the highest sensitivity, missing only 6% of urgent cases. With this strategy, only 49% (46% to 52%) of patients would have CT. Alternative strategies guided by body mass index, age, or location of the pain would all result in a loss of sensitivity., Conclusion: Although CT is the most sensitive imaging investigation for detecting urgent conditions in patients with abdominal pain, using ultrasonography first and CT only in those with negative or inconclusive ultrasonography results in the best sensitivity and lowers exposure to radiation.

The level of inter-observer agreement of abdominal computed tomography (CT) in unselected patients presenting with acute abdominal pain at the Emergency Department (ED) was evaluated. Two hundred consecutive patients with acute abdominal pain were prospectively included. Multi-slice CT was performed in all patients with intravenous contrast medium only. Three radiologists independently read all CT examinations. They recorded specific radiological features and a final diagnosis on a case record form. We calculated the proportion of agreement and kappa values, for overall, urgent and frequently occurring diagnoses. The mean age of the evaluated patients was 46 years (range 19-94), of which 54% were women. Overall agreement on diagnoses was good, with a median kappa of 0.66. Kappa values for specific urgent diagnoses were excellent, with median kappa values of 0.84, 0.90 and 0.81, for appendicitis, diverticulitis and bowel obstruction, respectively. Abdominal CT has good inter-observer agreement in unselected patients with acute abdominal pain at the ED, with excellent agreement for specific urgent diagnoses as diverticulitis and appendicitis.

The purpose was to investigate the diagnostic accuracy of graded compression ultrasonography (US) and computed tomography (CT) in diagnosing acute colonic diverticulitis (ACD) in suspected patients. We performed a systematic review and meta-analysis of the accuracy of CT and US in diagnosing ACD. Study quality was assessed with the QUADAS tool. Summary estimates of sensitivity and specificity were calculated using a bivariate random effects model. Six US studies evaluated 630 patients, and eight CT studies evaluated 684 patients. Overall, their quality was moderate. We did not identify meaningful sources of heterogeneity in the study results. Summary sensitivity estimates were 92% (95% CI: 80%-97%) for US versus 94% (95%CI: 87%-97%) for CT (p = 0.65). Summary specificity estimates were 90% (95%CI: 82%-95%) for US versus 99% (95%CI: 90%-100%) for CT (p = 0.07). For the identification of alternative diseases sensitivity ranged between 33% and 78% for US and between 50% and 100% for CT. The currently best available evidence shows no statistically significant difference in accuracy of US and CT in diagnosing ACD. Therefore, both US and CT can be used as initial diagnostic tool until new evidence is brought forward. However, CT is more likely to identify alternative diseases.

Purpose: This study was a head-to-head comparison of graded compression ultrasonography (US) and computed tomography (CT) in helping diagnose acute appendicitis with an emphasis on diagnostic value at different disease prevalences, commonly occurring in various hospital settings., Materials and Methods: MEDLINE, EMBASE, CINAHL, and Cochrane databases were searched from January 1966 to February 2006. Prospective trials were selected if they (a) compared graded compression US and CT in the same patient population; (b) included more than 10 patients, otherwise, the study was considered a case report; (c) evaluated mainly adults or adolescents; (d) used surgery and/or clinical follow-up as reference standard; and (e) reported data to calculate 2 x 2 contingency tables for graded compression US and CT. Estimates of sensitivity, specificity, and positive and negative likelihood ratios (LRs) for US and CT were calculated. Posttest probabilities after CT and US were calculated for various clinically relevant prevalences., Results: Six studies were included, evaluating 671 patients (mean age range, 26-38 years); prevalence of acute appendicitis was 50% (range, 13%-77%). Positive LR was 9.29 (95% confidence interval [CI]: 6.9, 12.6) for CT and 4.50 (95% CI: 3.0, 6.7; P = .011) for US, yielding posttest probabilities for positive tests of 90% and 82%, respectively. Negative LR was 0.10 (95% CI: 0.06, 0.17) for CT and 0.27 (95% CI: 0.17, 0.43) for US (P = .013), resulting in posttest probabilities of 9% and 21%, respectively. Posttest probabilities for positive tests were markedly decreased at lower prevalences., Conclusion: In head-to-head comparison studies of diagnostic imaging, CT had a better test performance than did graded compression US in diagnosing appendicitis. Ignoring the relationship between prevalence (pretest probability) and diagnostic value may lead to an inaccurate estimation of diagnostic performance., ((c) RSNA, 2008.)

The purpose was to evaluate low-dose CT colonography without cathartic cleansing in terms of image quality, polyp visualization and patient acceptance. Sixty-one patients scheduled for colonoscopy started a low-fiber diet, lactulose and amidotrizoic-acid for fecal tagging 2 days prior to the CT scan (standard dose, 5.8-8.2 mSv). The original raw data of 51 patients were modified and reconstructed at simulated 2.3 and 0.7 mSv levels. Two observers evaluated the standard dose scan regarding image quality and polyps. A third evaluated the presence of polyps at all three mSv levels in a blinded prospective way. All observers were blinded to the reference standard: colonoscopy. At three times patients were given questionnaires relating to their experiences and preference. Image quality was sufficient in all patients, but significantly lower in the cecum, sigmoid and rectum. The two observers correctly identified respectively 10/15 (67%) and 9/15 (60%) polyps > or =10 mm, with 5 and 8 false-positive lesions (standard dose scan). Dose reduction down to 0.7 mSv was not associated with significant changes in diagnostic value (polyps > or =10 mm). Eighty percent of patients preferred CT colonography and 13% preferred colonoscopy (P<0.001). CT colonography without cleansing is preferred to colonoscopy and shows sufficient image quality and moderate sensitivity, without impaired diagnostic value at dose-levels as low as 0.7 mSv.

Background: The acute abdomen is a frequent entity at the Emergency Department (ED), which usually needs rapid and accurate diagnostic work-up. Diagnostic work-up with imaging can consist of plain X-ray, ultrasonography (US), computed tomography (CT) and even diagnostic laparoscopy. However, no evidence-based guidelines exist in current literature. The actual diagnostic work-up of a patient with acute abdominal pain presenting to the ED varies greatly between hospitals and physicians. The OPTIMA study was designed to provide the evidence base for constructing an optimal diagnostic imaging guideline for patients with acute abdominal pain at the ED., Methods/design: Thousand consecutive patients with abdominal pain > 2 hours and < 5 days will be enrolled in this multicentre trial. After clinical history, physical and laboratory examination all patients will undergo a diagnostic imaging protocol, consisting of plain X-ray (upright chest and supine abdomen), US and CT. The reference standard will be a post hoc assignment of the final diagnosis by an expert panel. The focus of the analysis will be on the added value of the imaging modalities over history and clinical examination, relative to the incremental costs., Discussion: This study aims to provide the evidence base for the development of a diagnostic algorithm that can act as a guideline for ED physicians to evaluate patients with acute abdominal pain.

Purpose: To prospectively evaluate the diagnostic performance of magnetic resonance (MR) colonography by using limited bowel preparation in patients with polyps of 10 mm or larger in diameter in a population at increased risk for colorectal cancer, with optical colonoscopy as the reference standard., Materials and Methods: The institutional review boards of all three hospitals approved the study. All patients provided written informed consent. In this multicenter study, patients undergoing colonoscopy because of a personal or family history of colorectal cancer or adenomatous polyps were included. Two blinded observers independently evaluated T1- and T2-weighted MR colonographic images obtained with limited bowel preparation (bright-lumen fecal tagging) for the presence of polyps. The limited bowel preparation consisted of a low-fiber diet, with ingestion of lactulose and an oral gadolinium-based contrast agent (with all three major meals) starting 48 hours prior to imaging. Results were verified with colonoscopic outcomes. Patient sensitivity, patient specificity, polyp sensitivity, and interobserver agreement for lesions of 10 mm or larger were calculated for both observers individually and combined., Results: Two hundred patients (mean age, 58 years; 128 male patients) were included; 41 patients had coexistent symptoms. At colonoscopy, 12 patients had 22 polyps of 10 mm or larger. Per-patient sensitivity was 58% (seven of 12) for observer 1, 67% (eight of 12) for observer 2, and 75% (nine of 12) for both observers combined for polyps of 10 mm or larger. Per-patient specificity was 95% (178 of 188) for observer 1, 97% (183 of 188) for observer 2, and 93% (175 of 188) for both observers combined. Per-polyp sensitivity was 55% (12 of 22) for observer 1, 50% (11 of 22) for observer 2, and 77% (17 of 22) for both observers combined. Interobserver agreement was 93% for identification of patients with lesions of 10 mm or larger., Conclusion: In patients at increased risk for colorectal cancer, specificity of MR colonography by using limited bowel preparation was high, but sensitivity was modest.