Detection of Small Bowel Mucosal Healing and Deep Remission in Patients With Known Small Bowel Crohn's Disease Using Biomarkers, Capsule Endoscopy, and Imaging.

OBJECTIVES: Mucosal healing (MH) and deep remission (DR) are associated with improved outcomes in Crohn's disease (CD). However, most of the current data pertain to colonic MH and DR, whereas the evidence regarding the prevalence and impact of small bowel (SB) MH is scarce. The aim of this study was to to evaluate the prevalence of SBMH and DR in quiescent SBCD. METHODS: Patients with known SBCD in clinical remission (CDAI<150) or with mild symptoms (CDAI<220) were prospectively recruited and underwent video capsule endoscopy after verification of SB patency. Inflammation was quantified using the Lewis score (LS). SBMH was defined as LS<135, whereas a significant inflammation was defined as LS>790. Clinico-biomarker remission was defined as a combination of clinical remission and normal biomarkers. DR was defined as a combination of clinico-biomarker remission and MH. RESULTS: Fifty-six patients with proven SB patency were enrolled; 52 (92.9%) patients were in clinical remission and 21 (40.4%) in clinico-biomarker remission. SBMH was demonstrated in 8/52 (15.4%) of patients in clinical remission. Moderate-to-severe SB inflammation was demonstrated in 11/52 (21.1%) of patients in clinical remission and in 1/21 (4.7%) of patients in clinical and biomarker remission. Only 7/52 (13.5%) patients were in DR. CONCLUSIONS: SB inflammation is detected in the majority of CD patients in clinical and biomarker remission. SBMH and DR were rare and were independent of treatment modality. Our findings represent the true inflammatory burden in quiescent patients with SBCD.

Clinical Outcomes of Surgery Versus Endoscopic Balloon Dilation for Stricturing Crohn's Disease.

BACKGROUND: Endoscopic balloon dilation and surgery are commonly practiced in stricturing Crohn's disease. Nonetheless, there are still scant data directly comparing these 2 strategies. OBJECTIVE: The aim of this study was to compare the short- and long-term outcomes of endoscopic balloon dilation versus surgical resection in symptomatic Crohn's strictures. DESIGN: This was a retrospective cohort study. SETTINGS: The study was conducted at a single tertiary center. PATIENTS: Seventy-nine patients were identified, 40 in the surgical group and 39 in the endoscopic balloon dilation group (mean age 42.8 ± 13.9 versus 38.5 ± 12.2 years). MAIN OUTCOME MEASURES: The outcomes of all patients referred for endoscopic balloon dilation were compared with patients referred to surgery because of stricturing disease between the years 2006 and 2013. The primary outcome was the need for reintervention (either endoscopic balloon dilation or surgery) for symptomatic Crohn's disease during follow-up. RESULTS: The proportion of patients who required any reintervention during follow-up was significantly lower in the surgical group versus the endoscopic balloon dilation group (OR = 5.62 (95% CI, 1.66-19.01); p = 0.005). The need for surgery/resurgery during follow-up was also significantly lower in the surgically treated group (OR = 3.53 (95% CI, 1.01-12.29); p = 0.047). Reintervention-free survival and surgery-free survival were both significantly shorter in the endoscopically treated group in a Kaplan-Mayer analysis. The rate of major complications was similar in the endoscopically and surgically treated groups (7.6% versus 7.5%; p = 0.7). LIMITATIONS: The small cohort and the retrospective data collection were limitations of this study. CONCLUSIONS: In our cohort of patients with fibrostenotic Crohn's disease, a direct comparison showed reduced need for reinterventions with a similar rate of immediate major complications after surgery compared with endoscopic balloon dilation.

Machine learning for prediction of intra-abdominal abscesses in patients with Crohn's disease visiting the emergency department.

BACKGROUND: Intra-abdominal abscess (IA) is an important clinical complication of Crohn's disease (CD). A high index of clinical suspicion is needed as imaging is not routinely used during hospital admission. This study aimed to identify clinical predictors of an IA among hospitalized patients with CD using machine learning. METHODS: We created an electronic data repository of all patients with CD who visited the emergency department of our tertiary medical center between 2012 and 2018. We searched for the presence of an IA on abdominal imaging within 7 days from visit. Machine learning models were trained to predict the presence of an IA. A logistic regression model was compared with a random forest model. RESULTS: Overall, 309 patients with CD were hospitalized and underwent abdominal imaging within 7 days. Forty patients (12.9%) were diagnosed with an IA. On multivariate analysis, high C-reactive protein (CRP) [above 65 mg/l, adjusted odds ratio (aOR): 16 (95% CI: 5.51-46.18)], leukocytosis [above 10.5 K/µl, aOR: 4.47 (95% CI: 1.91-10.45)], thrombocytosis [above 322.5 K/µl, aOR: 4.1 (95% CI: 2-8.73)], and tachycardia [over 97 beats per minute, aOR: 2.7 (95% CI: 1.37-5.3)] were independently associated with an IA. Random forest model showed an area under the curve of 0.817 ± 0.065 with six features (CRP, hemoglobin, WBC, age, current biologic therapy, and BUN). CONCLUSION: In our large tertiary center cohort, the machine learning model identified the association of six clinical features (CRP, hemoglobin, WBC, age, BUN, and biologic therapy) with the presentation of an IA. These may assist as a decision support tool in triaging CD patients for imaging to exclude this potentially life-threatening complication.

PET-CT imaging features that differentiate between positive and negative EWSR1 translocation in Ewing sarcoma.

OBJECTIVES: Ewing sarcoma breakpoint region 1 (EWSR1) translocation-negative tumors represent a minor portion of small round cell tumors consistent with Ewing sarcoma morphology. The purpose of this study was to differentiate EWSR1 translocation-positive tumors from EWSR1 translocation-negative tumors using PET-computed tomography features. MATERIALS AND METHODS: In this retrospective study 27, Ewing sarcoma patients (December 2011 to November 2016) were divided into two groups, EWSR1 translocation-positive and EWSR1 translocation-negative based on cytogenetic analysis. Pretreatment standardized uptake value maximum (SUVmax) and Hounsfield Units (HU) were measured in the primary tumor in the axial slice with the largest tumor diameter.The associations between SUVmax, HU and the presence of EWSR1 translocation were evaluated. Receiver operating characteristic curve analysis was used to determine cut-off levels of SUVmax and HU suggestive of EWSR1-negative tumors. RESULTS: Twenty-one patients were classified as EWSR1-positive and six as EWSR1-negative. Eighteen had SUVmax and 21 had HU measurements. EWSR1-negative tumors had significantly higher SUVmax values (P = 0.003) and significantly lower HU values (P = 0.008). Receiver operating characteristic curve analysis showed that SUVmax had diagnostic ability to discriminate between EWSR1-negative and EWSR1-positive tumors (area under the curve = 0.964, P = 0.006). A SUVmax of at least 10 had a sensitivity of 100% and specificity of 85.7% for EWSR1-negative tumors. HU had lower diagnostic ability than SUVmax (area under the curve = 0.881, P = 0.012). A HU up to 57 had a sensitivity of 81.3% and specificity of 80.0% for EWSR1-negative tumors. CONCLUSION: Higher SUVmax and lower HU may differentiate between EWSR1-positive and EWSR1-negative tumors. This may reflect EWSR1-negative tumor aggressiveness.

Assessment of small bowel mucosal healing by video capsule endoscopy for the prediction of short-term and long-term risk of Crohn's disease flare: a prospective cohort study.

BACKGROUND: The optimal monitoring strategy for predicting disease course in Crohn's disease remains undefined. We aimed to evaluate the accuracy, safety, and tolerability of an intensive monitoring strategy designed to predict the future course of Crohn's disease in patients with quiescent disease. METHODS: In a prospective observational cohort study, we recruited patients older than 18 years with quiescent (for 3-24 months) Crohn's disease involving the small bowel with confirmed small bowel patency from three tertiary medical centres in Israel. Enrolled patients underwent baseline magnetic resonance enterography (MRE) and patency capsule, clinical or biomarker assessment every 3 months, and video capsule endoscopy (VCE) at baseline and every 6 months for 2 years or until a clinical flare (the primary outcome, defined as an increase in the Crohn's disease activity index score by 70 points or more) or disease worsening necessitating treatment intensification. We assessed the ability of the different Crohn's disease monitoring methods used to predict the occurrence of a flare during the 24-month follow-up period. FINDINGS: Of 90 screened patients, 29 were excluded (17 because of non-patent small bowel). Of the 61 patients enrolled between July 3, 2013, and Feb 1, 2015, 17 (28%) had a flare during the 24-month follow-up. No clinicodemographic parameter predicted future flare. A baseline VCE Lewis score of 350 or more identified patients with future flare (area under the curve [AUC] 0·79, 95% CI 0·66-0·88; p<0·0001; hazard ratio 10·7, 3·8-30·3). C-reactive protein at baseline had an AUC of 0·73 (0·6-0·84; p=0·0013) for predicting flare. The AUC of baseline faecal calprotectin for the prediction of flare occurring within 2 years was 0·62 (0·49-0·74; p=0·17), but progressively improved for shorter timespans and reached an AUC of 0·81 (0·76-0·85) for the prediction of flare occurring within 3 months. Of four MRE-based indices, only MRE global score correlated with 2-year flare risk (AUC 0·71, 0·58-0·82; p=0·024). During follow-up, a Lewis score increase of 383 points or more from baseline predicted imminent disease exacerbation within 6 months (AUC 0·79, 0·65-0·89; p=0·011). The safety and tolerability of the 231 VCEs ingested was excellent, with none being retained. INTERPRETATION: In patients with quiescent Crohn's disease involving the small bowel, faecal calprotectin predicts short-term flare risk, whereas VCE predicts both short-term and long-term risk of disease exacerbation. If corroborated by additional studies, protocols incorporating VCE could expand the scope of available methods for monitoring disease activity and predicting outcomes in small bowel Crohn's disease. FUNDING: The Leona M & Harry B Helmsley Charitable Trust.

Capsule Endoscopy Validation of the Magnetic Enterography Global Score in Patients with Established Crohn's Disease.

BACKGROUND AND AIMS: Capsule endoscopy [CE] and magnetic resonance enterography [MRE] are prime modalities for evaluation of the small bowel in Crohn's disease [CD]. Detection of proximal small bowel [SB] inflammation in CD by MRE is challenging. Currently available quantitative MRE scores do not incorporate proximal SB data. The MRE global score [MEGS] was designed for quantitative evaluation of the entire digestive tract; its accuracy in the proximal SB has not previously been evaluated. This study compared the evaluation of the small bowel inflammation by MEGS and CE-derived quantitative score (the Lewis score[LS]). METHODS: CD patients in stable clinical remission were prospectively recruited and underwent MRE and CE; faecal calprotectin [FC] levels were obtained. MEGS was calculated for each SB segment and the entire SB [SBMEGS]. SB inflammation on CE was quantified using LS. A cumulative Lewis score [C-LS] was calculated based on summation of three tertiles scores. RESULTS: Fifty patients were included. There was a significant correlation of SBMEGS with LS and C-LS [r = 0.61 and 0.71, both p = 0.001]. The correlation with FC was stronger for MEGS than for LS or C-LS [r = 0.68 vs r = 0.46 vs r = 0.53, all p = 0.001]. The correlation between the proximal LS and MEGS was significant [r = 0.55, p = 0.001]; median MEGS was significantly different in patients, with LS values consistent with mucosal healing, mild and moderate-to-severe inflammation. CONCLUSIONS: MEGS provides accurate evaluation of the SB and strongly correlates with FC; the main advantage of MEGS is the accurate quantification of proximal SB inflammation unavailable for alternative MRE scores.

Diffusion-weighted magnetic resonance enterography for prediction of response to tumor necrosis factor inhibitors in stricturing Crohn's disease.

BACKGROUND AND AIMS: Distinguishing between fibrotic and inflammatory strictures in Crohn's disease (CD) is still challenging. The capacity of diffusion-weighted (DWI) magnetic resonance (MRE) to identify intestinal fibrosis was recently demonstrated; however, the therapeutic implications of this association have never been evaluated. The aim of the current study was to identify imaging features, including DWI, which can predict response to anti-inflammatory treatment in patients with stricturing CD. METHODS: Consecutive CD patients with intestinal strictures that initiated treatment with anti-tumor necrosis alpha (anti-TNF) between June 2012 and April 2017 with MRE adjacent to treatment onset were retrospectively collected. The primary outcome was treatment failure, defined as drug discontinuation, CD-related surgery, or endoscopic dilatation of the stricture. Clinical, demographic, and imaging data were compared between patients who did and did not develop treatment failure within 12 months of anti-TNF treatment initiation. RESULTS: A total of 21 patients were included in the study; 9/21 (42.8%) developed treatment failure. None of the clinical/demographic parameters were associated with the risk of treatment failure. Among imaging parameters, only ADC value (< 1 × 10-3 mm2/s) was significantly associated with the risk of treatment failure (AUC = 0.81, 66% vs. 0%, p = 0.015). CONCLUSIONS: Our results suggest that ADC value on DWI MRE may predict the risk of treatment failure in stricturing CD. If replicated in larger studies, these results may guide therapeutic decisions and suggest avoiding anti-TNF treatment.

Structural bowel damage in quiescent Crohn's disease.

BACKGROUND: Crohn's disease is associated with accumulation of progressive structural bowel damage (SBD) leading to the development of stenotic and penetrating complications. The data pertaining to the course of progression of SBD is scarce. The Lemann index (LI) is a novel tool for evaluation of SBD that incorporates pan-enteric clinical, endoscopic and imaging data. AIMS: To evaluate the progression of SBD in quiescent CD patients. METHODS: Patients with known quiescent small bowel Crohn's disease (CD) for at least 3 months (CDAI<220) were prospectively recruited and underwent repeated magnetic resonance enterographies (MRE) and video capsule endoscopies (VCE). Patients were assessed for SBD on initial and follow-up evaluation using relevant clinicopathological data, MRE and VCE results. Significant structural bowel damage (SBD) was identified as LI>4.8, and progression of SBD as LI>0.3. RESULTS: Sixty one patients were enrolled in the study. Significant SBD was detected 13 (21.4%) on enrollment. Duration of disease (p=0.036) and history of CD-related surgery (p=0.0001) were associated with significant BD. Forty one patients underwent a follow-up MRE (14.8±2.5 months apart). LI was similar at baseline and follow-up. There was a negligible change in LI between the evaluations. CONCLUSIONS: In patients with quiescent Crohn's disease, structural bowel damage was stable over a median of 14 months follow-up.

Magnetic resonance enterography or video capsule endoscopy - what do Crohn's disease patients prefer?

BACKGROUND: Despite differences in the information obtained by capsule endoscopy (CE) and magnetic resonance enterography (MRE), one of these modalities is usually needed when evaluating disease activity. There are no data on patients' preference that would help guide the choice between these two modalities in these instances. AIM: To compare patients' tolerance and preference to MRE versus CE. PATIENTS AND METHODS: Patients with known small bowel Crohn's disease (CD) in clinical remission (Crohn's disease activity index [CDAI] <150) or with mild symptoms (CDAI <220) were prospectively recruited. All patients underwent MRE followed by CE. Patients were asked to fill out a questionnaire addressing specific points regarding inconvenience during the preparation for the procedures, the procedures, and postprocedures. Side effects and procedure preference were addressed. Questionnaires were included for analysis only when more than 95% of the items were addressed. RESULTS: Fifty-six patients fulfilled inclusion criteria. Pre-exam discomfort, during-exam discomfort, nausea, vomiting, bloating, and abdominal pain were all significantly more prominent in MRE as compared to CE (P<0.0001, P<0.0001, P<0.0001, P=0.009, P=0.0002, P<0.0001, respectively). MRE was perceived as a more difficult procedure (P<0.0001). Furthermore, MRE was associated with a specific adverse event - claustrophobia. Seventy-eight percent of patients (44 patients) preferred to repeat CE as compared to 22% (P<0.0001) who preferred MRE. CONCLUSION: CE was better tolerated by CD patients compared to MRE and was preferred by 78% of patients. The superior tolerability of CE should be considered along with the diagnostic features, and more data sought when choosing between these two modalities for CD patients for long-term follow-up.

The Impact of Magnetic Resonance Enterography and Capsule Endoscopy on the Re-classification of Disease in Patients with Known Crohn's Disease: A Prospective Israeli IBD Research Nucleus (IIRN) Study.

BACKGROUND AND AIMS: The classification of Crohn's disease (CD) is usually determined at initial diagnosis and is frequently based on ileocolonoscopic and cross-sectional imaging data. Advanced endoscopic and imaging techniques such as small-bowel video capsule endoscopy (VCE) and magnetic resonance enterography (MRE) may provide additional data regarding disease extent and phenotype. Our aim was to examine whether VCE or MRE performed after the initial diagnosis may alter the original disease classification. METHODS: Consecutive patients with known small-bowel CD in clinical remission or mild disease were prospectively recruited and underwent MRE and VCE (if small-bowel patency was confirmed by a patency capsule (PC). Montreal classifications before and after evaluation were compared. RESULTS: Seventy-nine patients underwent MRE and VCE was performed in 56. Previously unrecognized disease locations were detected with VCE and MRE in 51 and 25%, respectively (p < 0.01) and by both modalities combined in 44 patients (55%). Twenty-two patients (27%) were reclassified as having an advanced phenotype (B2/B3). MRE and VCE reclassified the phenotype in 26 and 11% of cases, respectively (p < 0.05). Overall, both modalities combined altered the original Montreal classification in 49/76 patients (64%). CONCLUSION: VCE and MRE may lead to reclassification of the original phenotype in a significant percentage of CD patients in remission. VCE was more sensitive for detection of previously unrecognized locations, while MRE was superior for detection of phenotype shift. The described changes in the disease classification may have an important impact on both clinical management and long-term prognosis in these patients.

Magnetic resonance enterography versus capsule endoscopy activity indices for quantification of small bowel inflammation in Crohn's disease.

BACKGROUND: Video capsule endoscopy (VCE) and magnetic resonance enterography (MRE) are the prime modalities for the evaluation of small bowel (SB) Crohn's disease (CD). Mucosal inflammation on VCE is quantified using the Lewis score (LS). Diffusion-weighted (DW) magnetic resonance imaging (MRI) allows for accurate assessment of SB inflammation without administration of intravenous contrast material. The Magnetic Resonance Index of Activity (MaRiA) and the Clermont index are quantitative activity indices validated for contrast-enhanced MRE and DW-MRE, respectively. The aim of this study was to compare the quantification of distal SB inflammation by VCE and MR-related activity indices. METHODS: Patients with known quiescent SB CD were prospectively recruited and underwent MRE and VCE. LS, MaRIA and Clermont scores were calculated for the distal SB. RESULTS: Both MRI-based indices significantly correlated with the LS and the Clermont index (r = 0.50, p = 0.001 and r = 0.53, p = 0.001, respectively). Both MaRIA and Clermont scores were significantly lower in patients with mucosal healing (LS < 135). The area under the curve (AUC) with both MR scores was moderate for prediction of any mucosal inflammation (LS ⩾ 135) and excellent for prediction of moderate-to-severe inflammation (LS ⩾ 790) (0.71 and 0.74 versus 0.93 and 0.91 for MaRIA and Clermont score, respectively). CONCLUSIONS: Modest correlation between VCE- and MRE-based quantitative indices of inflammation in patients with quiescent SB CD was observed. Between-modality correlation was higher in patients with endoscopically severe disease. DW-MRE gauged by Clermont score was at least as accurate as contrast-enhanced MRE for quantification of SB inflammation.

Magnetic resonance enterography in Crohn's disease: a guide to common imaging manifestations for the IBD physician.

Patients with Crohn's disease (CD) frequently require cross-sectional imaging. Magnetic resonance enterography (MRE) is an accurate tool for assessment of bowel disease and of various complications of CD. The lack of non-ionizing radiation exposure is an important advantage of this imaging modality. Familiarity with common and pathognomonic imaging features of CD is essential for every clinician that is involved in inflammatory bowel disease (IBD) patients' care. This review is aimed to describe the indications for performing MRE in CD, essentials of MRE techniques and typical radiological findings in patients with CD to aid the IBD doctor in daily practice.

Correlation between MRI and double-balloon urethrography findings in the diagnosis of female periurethral lesions.

This study aims to evaluate the correlation of MRI findings with double-balloon urethrography (DBU) in diagnosing female urethral diverticula and other periurethral lesions. In this retrospective study, females with clinically suspected periurethral lesions who underwent both MRI and DBU between 2008 and 2012 were evaluated. MRI was performed on a 1.5 Tesla unit using a pelvic phased array coil. Protocol included small FOV pelvic images, multiplanar T2-w, T1-w with and without contrast injection. DBU was performed by a dedicated catheter. Images were evaluated in consensus by two readers. Diverticula were evaluated by, size, number, complexity, location and connection to urethra, and other periurethral lesions were evaluated by size, location and connection. Supplement clinical and surgical data were retrieved from medical records and telephone interviews. Seventeen females (mean age 44 years, range 20-69) were included in the study. Diverticula were diagnosed by both modalities (9 cases), by neither (6 cases, 88% correlation) by MRI alone (1 case) and by DBU alone (1 case). Among diverticula, correlation of number, complexity, location and demonstration of connection to urethra was 89%, 67%, 67%, and 56%, respectively. Alternative diagnosis solely by MRI included vaginal wall cysts (3 cases), endometriosis (1 case) and ectopic ureter (1 case). No periurethral lesion was found by either modality in 2 cases. The correlation between MRI and DBU in diagnosing female periurethral lesions is very good for anatomical delineation of diverticula. MRI, which does not involve radiation, may also indicate alternative diagnoses that can contribute to proper patient management.

Clinical and radiographic presentation of superior mesenteric vein thrombosis in Crohn's disease: a single center experience.

BACKGROUND: Mesenteric vein thrombosis (MVT) is a rare and frequently underdiagnosed complication of Crohn's disease (CD). This study describes the clinical and radiological characteristics of CD /patients with superior mesenteric vein thrombosis (MVT) diagnosed by CT/MRI. PATIENTS AND METHODS: The database of Crohn's disease patients treated in Sheba Medical Center between 2005-2010 was searched for MVT diagnosis. Imaging studies of identified patients were retrieved and reviewed by an experienced abdominal radiologist. MVT was defined by superior mesenteric vein obliteration and/or thrombus in the vessel lumen on abdominal imaging. The clinical and radiologic data of these patients were collected from the medical records. RESULTS: MVT was demonstrated in 6/460 CD patients. Five patients had stricturing disease, and one patient had a combined fistulizing and stricturing disease phenotype. All patients had small bowel disease, but 3/6 also had colonic involvement. No patient had a prior thromboembolic history or demonstrable hypercoagulability. One patient had an acute SMV thrombus demonstrable on CT scanning, the remaining patients showed an obliteration of superior mesenteric vein. Two patients received anticoagulation upon diagnosis of thrombosis. No subsequent thromboembolic events were recorded. CONCLUSIONS: The incidence of mesenteric vein thrombosis is likely to be underestimated in patients with Crohn's disease. Both CT and MRI imaging demonstrate the extent of enteric disease and coincident SMV thrombosis. In our cohort, thrombosis was associated with stricturing disease of the small bowel. The clinical impact of SMV thrombosis and whether anticoagulation is mandatory for all of these patients remains to be determined.

Gas in the kidney: CT findings.

Gas in the renal parenchyma is a rare finding seen best with computed tomography (CT). It can be encountered in a wide range of clinical conditions, some of them life-threatening like emphysematous pyelonephritis, whereas in others, it may represent a postoperative or procedure outcome. The latter are not usually a clinical emergency (for example, after nephrostomy insertion or in a urinary intestinal connection). Due to the increasing use of abdominal CT examinations, radiologists, especially in emergency setting, should be aware of this rare finding and be familiar with its differential diagnosis.

Multi-detector row helical CT in preoperative assessment of small (< or = 1.5 cm) liver metastases: is thinner collimation better?

PURPOSE: To determine the value of collimations less than 5 mm in detecting hepatic metastases 1.5 cm or smaller by using multi-detector row helical computed tomography (CT). MATERIALS AND METHODS: Thirty-one patients underwent contrast material-enhanced multi-detector row helical CT before hepatic resection in this prospective study. Images were reconstructed at collimations of 5.00, 3.75, and 2.50 mm with 50% overlap and reviewed independently by three radiologists. Each lesion was characterized as metastatic, benign, or equivocal and graded for conspicuity. Criterion standards were pathologic assessment of the resected liver and follow-up of the nonresected liver. Only lesions 1.5 cm or smaller were analyzed. RESULTS: There were a total of 88 liver lesions 1.5 cm or smaller, and 25 of these were metastases. Pooled sensitivity for all lesions improved with thinner collimation (66% [58 of 88 lesions], 69% [61 of 88], and 82% [72 of 88] at collimations of 5.00, 3.75, and 2.50 mm, respectively), and this was statistically significant (P =.01). However, no significant difference was noted between collimations in the pooled sensitivity for metastatic lesions (80% [20 of 25 lesions] at all collimations) (P >.99). No statistical difference was noted in the conspicuity of lesions at different collimations (P =.18). CONCLUSION: Image reconstruction with multi-detector row helical CT at collimations less than 5 mm may not improve sensitivity in the detection of hepatic metastases 1.5 cm or smaller.