MR-enterography: role in the assessment of suspected anastomotic recurrence of Crohn disease after ileocolic resection.

PURPOSE: To determine the potential of magnetic resonance-enterography (MRE) in the assessment of the anastomotic status in patients with Crohn disease and prior ileocolic resection. METHODS: A total of 62 MRE examinations obtained in 52 patients with Crohn disease who had previously undergone ileocolic resection were retrospectively reviewed by two readers in consensus. MRE features (anastomotic wall thickening, wall stratification, wall enhancement pattern and degree, DWI signal intensity, ADC values, lymph nodes, comb sign and complications) were compared to clinical, endoscopic and histological findings that served as standard of reference. Sensitivity, specificity and accuracy of MRE were calculated. RESULTS: At univariate analysis, anastomotic wall thickening, anastomotic wall stratification, segmental wall enhancement, moderate wall enhancement, early and mucosal enhancement, and moderate/marked hyperintensity on diffusion-weighed imaging (DWI) were the most discriminative MRE features for differentiating between normal and abnormal anastomoses (p < 0.001 for all variables). Anastomotic wall thickening and segmental anastomotic wall enhancement were the two most sensitive and accurate MRE variables for the diagnosis of abnormal anastomosis with sensitivities of 82% (95% CI: 67-92%) and accuracies of 84% (95% CI: 72-92%). At univariate analysis, hyperintensity on DWI of the anastomotic site was the most sensitive finding for distinguishing between inflammatory recurrence and fibrostenosis (sensitivity, 89%; 95% CI: 67-99%). CONCLUSIONS: MRE provides objective and relatively specific morphological criteria that help detect abnormal ileocolic anastomosis, but performances are lower when differentiating between inflammatory recurrence and fibrostenosis. DWI may be useful in identifying pathologic anastomosis and, in particular, in distinguishing between inflammatory recurrence and fibrostenosis.

Development of a New Index to Assess Small Bowel Inflammation Severity in Crohn's Disease Using Magnetic Resonance Enterography.

Background: The severity of small bowel (SB) inflammation in Crohn's disease (CD) patients is a key component of the therapeutic choice. We aimed to develop a SB-CD Magnetic Resonance Enterography (MRE) index of Inflammation Severity (CDMRIS). Methods: Each gastroenterologist/radiologist pair in 13 centers selected MREs from 6 patients with SB-CD stratified on their perceived MRE inflammation severity. The 78 blinded MREs were allocated through balanced incomplete block design per severity stratum to these 13 pairs for rating the presence/severity of 13 preselected items for each SB 20-cm diseased segment. Global inflammation severity was evaluated using a 100-cm visual analog scale. Reproducibility of recorded items was evaluated. The CDMRIS was determined through linear mixed modeling as a combination of the numbers of segments with lesions highly correlated to global inflammation severity. Results: Four hundred and forty-two readings were available. Global inflammation severity mean ± SD was 21.0 ± 16.2. The independent predictors explaining 54% of the global inflammation severity variance were the numbers of segments with T1 mild-moderate and severe intensity of enhancement, deep ulceration without fistula, comb sign, fistula, and abscess. Unbiased correlation between CDMRIS and global inflammation severity was 0.76. Conclusions: The CDMRIS is now available to evaluate the severity of SB-CD inflammation. External validation and sensitivity-to-change are mandatory next steps.

Computed Tomographic Features of Primary Small Cell Neuroendocrine Tumors of the Gallbladder.

PURPOSE: This study aimed to report the computed tomography (CT) imaging features of primary small cell neuroendocrine tumors of the gallbladder (PSCNETGs). MATERIALS AND METHODS: The CT examinations of 9 patients (5 women, 4 men; median age, 57 years) with histopathologically proven PSCNETG were reviewed. Computed tomographic images were analyzed with respect to morphologic features of primary tumors and accompanying lymph nodes. RESULTS: All PSCNETGs were visible on CT, with a median largest axial diameter of 60 mm (Q1, 30 mm; Q3 mm, 82; range, 25-86 mm). These tumors presented with extraluminal growth (8/9; 89%), heterogeneous enhancement (8/9; 89%), gallbladder replacement greater than 50% (5/9; 56%), hepatic metastases (5/9; 56%), and direct liver involvement by tumor (4/9; 44%). Enlarged lymph nodes were present in all patients (9/9; 100%) with a median largest axial diameter of 39 mm (Q1, 23 mm; Q3, 48 mm; range, 12-62 mm). Vessel encasement by lymph nodes was present in 6 (67%) of 9 patients. CONCLUSION: Primary small cell neuroendocrine tumors of the gallbladder predominantly presents as a large, heterogeneous gallbladder mass with extraluminal growth in association with large metastatic lymph nodes and intrahepatic metastases.

Detection of small-bowel tumours with CT enteroclysis using carbon dioxide and virtual enteroscopy: A preliminary study.

PURPOSE: The aim of this prospective study was to evaluate the feasibility, tolerance and performance of virtual enteroscopy (VE) using carbon dioxide for small-bowel distension in patients with suspected small-bowel tumours (SBTs). PATIENTS AND METHODS: After IRB approval, 17 patients with suspected SBTs were prospectively included. Radiation dose was compared to 34 matched patients (2 for 1) for age, gender and body weight, who had undergone CT-enteroclysis with neutral contrast (CTE). Performance of VE was evaluated through comparison with the current standard of reference, including surgery and/or enteroscopy and/or follow-up. RESULTS: Tolerance was excellent in 16/17 patients (94%). The radiation dose was lower for VE than for CTE (533 ± 282 vs. 974 ± 505 mGy.cm; p = 0.002). With VE, a total of 25 polyps >5 mm in size were depicted in 12/17 patients. On a per-lesion analysis, sensitivity and positive predictive value of VE were 92.0% and 92.0%, respectively. On a per-segment analysis VE had a sensitivity and specificity of 95.0% and 87.0%, respectively. CONCLUSION: Our preliminary study suggests that VE is a feasible and well-tolerated technique with high sensitivity and specificity for the diagnosis of SBT. KEY POINTS: • Virtual enteroscopy is feasible and well tolerated. • Virtual enteroscopy appears to be accurate for detection of small-bowel tumours. • Sensitivity and PPV of virtual enteroscopy is 92.0% and 92.0%. • Radiation dose is lower with virtual enteroscopy compared to MDCT-enteroclysis.

Cancer of the Anal Canal: Diagnosis, Staging and Follow-Up with MRI.

Although a rare disease, anal cancer is increasingly being diagnosed in patients with risk factors, mainly anal infection with the human papilloma virus. Magnetic resonance imaging (MRI) with external phased-array coils is recommended as the imaging modality of choice to grade anal cancers and to evaluate the response assessment after chemoradiotherapy, with a high contrast and good anatomic resolution of the anal canal. MRI provides a performant evaluation of size, extent and signal characteristics of the anal tumor before and after treatment, as well as lymph node involvement and extension to the adjacent organs. MRI is also particularly helpful in the assessment of complications after treatment, and in the diagnosis for relapse of the diseases.

One-month apparent diffusion coefficient correlates with response to radiofrequency ablation of hepatocellular carcinoma.

PURPOSE: To assess whether apparent diffusion coefficient (ADC) values at 1 and 3 months after radiofrequency ablation (RFA) may be associated with a favorable response to therapy for hepatocellular carcinoma (HCC) and liver metastases. MATERIALS AND METHODS: Fifty-nine patients with HCC (n = 35) or liver metastases (n = 24) who underwent 1.5T diffusion-weighted magnetic resonance imaging (DWMRI) at 1 and 3 months post-RFA were included. ADC values of patients with local tumor recurrence were compared to those without local recurrence. A subgroup analysis was performed for HCC and metastases. RESULTS: Thirty-eight HCC and 27 metastases were evaluated. The ADC value of HCC at 1 month after RFA was lower in recurrent tumors (0.957 ± 0.229 [SD] × 10-3 mm2 ) compared to tumors with complete response (1.414 ± 0.322 [SD] × 10-3 mm2 /s, P = 0.006). At multivariate analysis, ADC at 1 month was the single independent variable associated with recurrence for HCC (area under the receiver operating characteristic curve = 0.860). No significant association was observed for liver metastases (P = 0.089). CONCLUSION: A low ADC value at 1 month after RFA is associated with an early local recurrence of HCC. This study does not confirm that such association exists for hepatic metastases. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;45:1648-1658.

Diffusion-weighted MRI in Crohn's disease: Current status and recommendations.

Over the past years, technological improvements and refinements in magnetic resonance imaging (MRI) hardware have made high-quality diffusion-weighted imaging (DWI) routinely possible for the bowel. DWI is promising for the detection and characterization of lesions in Crohn's disease (CD) and has been advocated as an alternative to intravenous gadolinium-based contrast agents. Furthermore, quantification using the apparent diffusion coefficient may have value as a biomarker of CD activity and has shown promise. In this article we critically review the literature pertaining to the value of DWI in CD for detection, characterization, and quantification of disease activity and complications. Although the body of supportive evidence is growing, it is clear that well-designed, multicenter studies are required before the role of DWI in clinical practice can be fully established. J. Magn. Reson. Imaging 2016;44:1381-1396.

Neuroendocrine tumors of the small bowel: evaluation with MR-enterography.

PURPOSE: To determine the sensitivity of magnetic resonance (MR)-enterography for the detection of neuroendocrine tumors of the small-bowel (NETSB) and analyze the imaging presentation of NETSB on MR-enterography. PATIENTS & METHODS: The MR-enterography studies (including HASTE, TruFISP, and 3D VIBE MR sequences before and after intravenous administration of a gadolinium-chelate) of 19 patients with pathologically confirmed NETSB were blindly reviewed. Images were analyzed with respect to imaging presentation. Sensitivity of MR-enterography as well as that of each individual MR-enterography sequence for the diagnosis of NETSB was estimated with 95% confidence intervals (CIs). Comparisons between individual MR-enterography sequences were performed using the McNemar test. RESULTS: Twenty-seven NETSBs were confirmed in 19 patients. Overall sensitivity of MR-enterography for NETSB detection was 74% (20/27; 95% CI: 54-89%) on a per-lesion basis. On a per-patient basis, MR-enterography had a sensitivity of 95% (18/19; 95% CI: 74-100%) for the detection of NETSB. Best degrees of sensitivity were achieved with 3D VIBE MR-enterography sequences after intravenous administration of a gadolinium-chelate (Se=95%; 18/19) by comparison with HASTE (Se=26%; 5/19) and TruFISP (Se=26%; 5/19) sequences (P=.00022). Visible focal small-bowel mass, mesenteric stranding, and mesenteric mass were found in 16/19 (84%), 17/19 (89%), and 15/19 (79%) patients, respectively. CONCLUSION: MR-enterography shows highly suggestive features for the diagnosis of NETSB and has high degrees of sensitivity for the diagnosis of NETSB on a per-patient basis.

Acute colonic diverticulitis: an update on clinical classification and management with MDCT correlation.

Currently, the most commonly used classification of acute colonic diverticulitis (ACD) is the modified Hinchey classification, which corresponds to a slightly more complex classification by comparison with the original description. This modified classification allows to categorize patients with ACD into four major categories (I, II, III, IV) and two additional subcategories (Ia and Ib), depending on the severity of the disease. Several studies have clearly demonstrated the impact of this classification for determining the best therapeutic approach and predicting perioperative complications for patients who need surgery. This review provides an update on the classification of ACD along with a special emphasis on the corresponding MDCT features of the different categories and subcategories. This modified Hinchey classification should be known by emergency physicians, radiologists, and surgeons in order to improve patient care and management because each category has a specific therapeutic approach.

MR imaging features of liver involvement by Wilson disease in adult patients.

OBJECTIVE: To describe the magnetic resonance imaging (MRI) presentation of liver involvement in adult patients with Wilson disease (WD) and determine the most indicative appearance of this condition on MRI using a retrospective case-control study. MATERIALS AND METHODS: MRI examinations of 23 adult patients with WD (14 men, 9 women; mean age = 40.4 years) were analyzed by two blinded observers and compared to those obtained in 23 patients with chronic viral hepatitis (14 men, 9 women, mean age = 40.4 years) who were matched for age, gender and severity of chronic liver disease. Images were qualitatively and quantitatively analyzed with respect to imaging presentation. Comparisons were performed using univariate analysis. RESULTS: Honeycomb pattern of hepatic parenchyma was the most discriminating independent variable for the diagnosis of WD (odds ratio, 17.082; 95 % CI 2.092-139.497) (P = 0.0081) but had a sensitivity of 43 % (10/23; 95 % CI 23-66 %). Regular liver contours was the other variable that strongly correlated with the presence of liver involvement by WD (odds ratio, 11.939; 95 % CI 1.503-94.836) (P = 0.0190). CONCLUSION: The honeycomb pattern is the most discriminating independent variable for the diagnosis of liver involvement by WD but has limited sensitivity. Familiarity with this finding may clarify the cause of diffuse hepatic parenchymal abnormalities in patients with unknown WD.

MR imaging features of focal liver lesions in Wilson disease.

Hepatic involvement in Wilson disease (WD) manifests as a diffuse chronic disease in the majority of patients. However, in a subset of patients focal liver lesions may develop, presenting with a wide range of imaging features. The majority of focal liver lesions in patients with WD are benign nodules, but there are reports that have described malignant liver tumors or dysplastic nodules in these patients. Because of the possibility of malignant transformation of liver nodules, major concerns have been raised with respect to the management and follow-up of patients with WD in whom focal liver lesions have been identified. The assessment of liver involvement in patients with WD is generally performed with ultrasonography. However, ultrasonography conveys limited specificity so that magnetic resonance (MR) imaging is often performed to improve lesion characterization. This review was performed to illustrate the spectrum of MR imaging features of focal liver lesions that develop in patients with WD. It is assumed that familiarity with the MR imaging presentation of focal liver lesions in WD may help clarify the actual nature of hepatic nodules in patients with this condition.

Diffusion-weighted MR imaging of uterine leiomyomas following uterine artery embolization.

PURPOSE: To test whether variations in apparent diffusion coefficient (ADC) values of uterine leiomyomas after uterine artery embolization (UAE) may correlate with outcome and assess the effects of UAE on leiomyomas and normal myometrium with magnetic resonance imaging (MRI). METHODS: Data of 49 women who underwent pelvic MRI before and after UAE were retrospectively reviewed. Uterine and leiomyoma volumes, ADC values of leiomyomas, and normal myometrium were calculated before and after UAE. RESULTS: By comparison with baseline ADC values, a significant drop in leiomyoma ADC was found at 6-month post-UAE (1.096 × 10(-3) mm(2)/s vs. 0.712 × 10(-3) mm(2)/s, respectively; p < 0.0001), but not at 48-h post-UAE. Leiomyoma devascularization was complete in 40/49 women (82 %) at 48 h and in 37/49 women (76 %) at 6 months. Volume reduction and leiomyoma ADC values at 6 months correlated with the degree of devascularization. There was a significant drop in myometrium ADC after UAE. Perfusion defect of the myometrium was observed at 48 h in 14/49 women (28.5 %) in association with higher degrees of leiomyoma devascularization. CONCLUSION: Six months after UAE, drop in leiomyoma ADC values and volume reduction correlate with the degree of leiomyoma devascularization. UAE affects the myometrium as evidenced by a drop in ADC values and initial myometrial perfusion defect. KEY POINTS: • A drop in leiomyoma ADC values is observed 6 months after UAE. • Drop in leiomyoma ADC value is associated with leiomyoma devascularizarion after UAE. • MR 48 h post-UAE allows assessing leiomyoma devascularization. • Myometrium perfusion defect occurs more often in women with a smaller uterus.

Gastrointestinal cancers in inflammatory bowel disease: An update with emphasis on imaging findings.

Inflammatory bowel diseases (IBD) are associated with an increased risk of gastrointestinal cancers depending on the specific type of IBD, the extent of the disease and its location. Patients with IBD and extensive colonic involvement are at increased risk of colorectal cancer whereas patients with Crohn disease have an increased risk for small-bowel and anal carcinoma. These cancers preferentially develop on sites of longstanding inflammation. In regards to colon cancer, several key pathogenic events are involved, including chromosomal instability, microsatellite instability and hypermethylation. The risk for colon cancer in IBD patients correlates with longer disease duration, presence of sclerosing cholangitis, pancolitis, family history of colorectal cancer, early onset of the disease and severity of bowel inflammation. Identification of increased colorectal cancer risk in individual IBD patients has led to formal surveillance guidelines. Conversely, although an increased risk for other types of cancer has been well identified, no specific formal screening recommendations exist. Consequently, the role of the radiologist is crucial to alert the referring gastroenterologist when a patient with IBD presents with unusual imaging findings at either computed tomography (CT) or magnetic resonance (MR) imaging. This review provides an update on demographics, molecular, clinical and histopathological features of gastrointestinal cancers in IBD patients including colorectal carcinoma, small bowel adenocarcinoma, neuroendocrine tumors and anal carcinoma, along with a special emphasis on the current role of CT and MR imaging.

Hepatic involvement in HELLP syndrome: an update with emphasis on imaging features.

HELLP syndrome, which consists of hemolysis, elevated liver enzymes, and low platelet count is an unusual complication of pregnancy that is observed in only 10% to 15% of women with preeclampsia. Hepatic involvement in HELLP syndrome may present with various imaging features depending on the specific condition that includes nonspecific abnormalities such as perihepatic free fluid, hepatic steatosis, liver enlargement, and periportal halo that may precede more severe conditions such as hepatic hematoma and hepatic rupture with hemoperitoneum. Maternal clinical symptoms may be nonspecific and easily mistaken for a variety of other conditions that should be recognized. Because hepatic hematoma occurring in association with preeclampsia and HELLP syndrome is a potentially life-threatening complication, prompt depiction is critical and may help reduce morbidity and mortality. This review provides an update on demographics, risk factors, pathophysiology, and clinical features of hepatic complications due to HELLP syndrome along with a special emphasis on the imaging features of these uncommon conditions.

Clinical and imaging factors associated with severe complications of cervical necrotizing fasciitis.

PURPOSE: Cervical necrotizing fasciitis (CNF) is a severe and debilitating disease that requires intensive care unit (ICU) management and prompt surgical treatment to reduce morbidity and mortality. The aim of this study was to estimate the incidence and factors associated with severe complications of CNF. METHODS: We reviewed the medical records of consecutive patients hospitalized in an ICU from 2007 to 2012. The data were collected retrospectively; initial cervical and thoracic computed tomography (CT) scans, performed on admission, were reviewed by an experienced and blinded radiologist to determine CNF complications. RESULTS: A cohort of 160 patients admitted for CNF was included. The following complications of CNF were found: bilateral extension of CNF (28%), internal jugular vein thrombosis (21%), descending necrotic effusion (14%), mediastinitis (24%), and mortality (4%); 53% had at least one complication, and 48% had at least one cervical complication. On the basis of a univariate analysis, the significant independent factors are odynophagia, dyspnea, oral glucocorticoids intake before admission, and pharyngeal source. Oral nonsteroidal anti-inflammatory drug intake before admission does not have any impact. The initial CNF complications increased both the duration of mechanical ventilation and the length of stay in the ICU. On the basis of a multivariate analysis, the independent factors for severe complications are pharyngeal CNF and oral glucocorticoid intake before admission. CONCLUSIONS: Our study demonstrated that an initial cervico-thoracic CT scan revealed a high incidence of cervical and mediastinal CNF complications that all needed immediate management. Those severe complications might be avoidable as they were associated, at least partially, with prehospital oral glucocorticoid intake.

Intrahepatic and hilar mass-forming cholangiocarcinoma: Qualitative and quantitative evaluation with diffusion-weighted MR imaging.

OBJECTIVE: To qualitatively and quantitatively analyze the presentation of intrahepatic and hilar mass-forming cholangiocarcinoma with diffusion-weighted magnetic resonance imaging (DW-MRI). MATERIALS AND METHODS: Twenty-eight patients with histopathologically proven mass-forming cholangiocarcinoma (hilar, n=17; intrahepatic, n=11) underwent hepatic DW-MRI at 1.5-T using free-breathing acquisition and three b-values (0,400,800s/mm(2)). Cholangiocarcinomas were evaluated qualitatively using visual analysis of DW-MR images and quantitatively with conventional ADC and normalized ADC measurements using liver and spleen as reference organs. RESULTS: All cholangiocarcinomas (28/28; 100%) were visible on DW-MR images. DW-MRI yielded best conspicuity of cholangiocarcinomas than the other MRI sequences (P<0.001). Seven cholangiocarcinomas (7/11; 64%) showed hypointense central area on DW-MR images. Conventional ADC value of cholangiocarcinomas (1.042×10(-3)mm(2)/s±0.221×10(-3)mm(2)/s; range: 0.616×10(-3)mm(2)/s to 2.050×10(-3)mm(2)/s) was significantly lower than that of apparently normal hepatic parenchyma (1.362×10(-3)mm(2)/s±0.187×10(-3)mm(2)/s) (P<0.0001), although substantial overlap was found. No significant differences in ADC and normalized ADC values were found between intrahepatic and hilar cholangiocarcinomas. The use of normalized ADC using the liver as reference organ resulted in the most restricted distribution of ADC values of cholangiocarcinomas (variation coefficient=16.6%). CONCLUSION: There is a trend towards a common appearance of intrahepatic and hilar mass-forming cholangiocarcinomas on DW-MRI but variations may be observed. Familiarity with these variations may improve the diagnosis of mass-forming cholangiocarcinoma.

Transcatheter Arterial Embolization for Postpartum Hemorrhage: Indications, Technique, Results, and Complications.

Postpartum hemorrhage (PPH) is a potentially life-threatening condition, which needs multidisciplinary management. Uterine atony represents up to 80 % of all causes of PPH. Transcatheter arterial embolization (TAE) has now a well-established role in the management of severe PPH. TAE allows stopping the bleeding in 90 % of women with severe PHH, obviating surgery. Pledgets of gelatin sponge as torpedoes are commonly used for safe TAE, and coils, glue, and microspheres have been primarily used in specific situations such as arterial rupture, pseudoaneurysm, and arteriovenous fistula. TAE is a minimally invasive procedure with a low rate of complications, which preserves future fertility. Knowledge of causes of PPH, potential risks, and limitations of TAE is essential for a timely decision, optimizing TAE, preventing irreversible complications, avoiding hysterectomy, and ultimately preserving fertility.

Role and Effectiveness of Percutaneous Arterial Embolization in Hemodynamically Unstable Patients with Ruptured Splanchnic Artery Pseudoaneurysms.

PURPOSE: To assess the role and effectiveness of percutaneous arterial embolization (TAE) in patients with hemodynamic instability due to hypovolemic shock secondary to ruptured splanchnic artery pseudoaneurysms (SAPA). MATERIALS AND METHODS: Seventeen patients (11 men, 6 women; mean age, 53 years) with hemodynamic instability (systolic blood pressure <90 mmHg) due to hypovolemic shock secondary to ruptured SAPA were treated by TAE. Clinical files, multidetector row computed tomography angiography, and angiographic examinations along with procedure details were reviewed. RESULTS: Seventeen SAPAs were present, predominantly located on gastroduodenal or pancreatic arteries (9/17; 53%). Angiography showed extravasation of contrast medium from SAPA in 15/17 patients (88%). Technical success rate of TAE was 100%. TAE was performed using metallic coils in all patients (100%), in association with gelatin sponge in 5/17 patients (29%). TAE allowed controlling the bleeding and returning to normal hemodynamic status in 16/17 patients (94%). In 1/17 patient (6%), surgery was needed to definitively control the bleeding. The mortality and morbidity rate of TAE at 30 days were 0 and 12%, respectively. Morbidity consisted in coil migration in 1/17 patient (6%) and transient serum liver enzyme elevation in 1/17 patient (6%). CONCLUSION: TAE is an effective and safe treatment option for ruptured SAPA in hemodynamically unstable patients, with a success rate of 94%. Our results suggest that TAE should be the favored option in patients with hemodynamic instability due to ruptured SAPA.

Update on imaging of Peutz-Jeghers syndrome.

Peutz-Jeghers syndrome (PJS) is a rare, autosomal dominant disease linked to a mutation of the STK 11 gene and is characterized by the development of benign hamartomatous polyps in the gastrointestinal tract in association with a hyperpigmentation on the lips and oral mucosa. Patients affected by PJS have an increased risk of developing gastrointestinal and extra-digestive cancer. Malignancy most commonly occurs in the small-bowel. Extra-intestinal malignancies are mostly breast cancer and gynecological tumors or, to a lesser extent, pancreatic cancer. These polyps are also at risk of acute gastrointestinal bleeding, intussusception and bowel obstruction. Recent guidelines recommend regular small-bowel surveillance to reduce these risks associated with PJS. Small-bowel surveillance allows for the detection of large polyps and the further referral of selected PJS patients for endoscopic enteroscopy or surgery. Video capsule endoscopy, double balloon pushed enteroscopy, multidetector computed tomography and magnetic resonance enteroclysis or enterography, all of which are relatively new techniques, have an important role in the management of patients suffering from PJS. This review illustrates the pathological, clinical and imaging features of small-bowel abnormalities as well as the role and performance of the most recent imaging modalities for the detection and follow-up of PJS patients.

Diffusion-weighted MR imaging for the diagnosis of abscess complicating fistula-in-ano: preliminary experience.

OBJECTIVE: To investigate the role of diffusion-weighted magnetic resonance imaging (DWMRI) in the diagnosis of abscess-complicating fistula-in-ano. METHODS: This retrospective study was approved by our Institutional Review Board and informed consent was waived. MRI examinations, including fat-suppressed T2-weighted turbo spin-echo (T2-TSE) MRI and DWMRI, of 24 patients with a fistula-in-ano, were reviewed by two independent readers for the presence and number of visible fistulas, conspicuity and apparent diffusion coefficient (ADC) measurement of suspected fistula tracks and pelvic collections. The reference standard was surgical with follow-up findings. RESULTS: Sensitivity was 91.2 % [95 % CI: 76 %-98 %] for T2-weighted TSE MRI and 100 % [95 % CI: 90 %-100 %] for DWMRI detecting fistulas. ADC values were lower in abscesses than in inflammatory masses (P = 0.714.10(-6)). The area under the ROC curve was 0.971 and the optimal cut-off ADC value was 1.186 × 10(-3) mm(2)/s, yielding a sensitivity of 100 % [95 % CI: 77 %-100 %], a specificity of 90 % [95 % CI: 66 %-100 %], a positive predictive value of 93 % [95 % CI: 82.8 %-100 %] and a negative predictive value of 90 % [95 % CI: 78 %-100 %] for an abscess diagnosis. Fistula conspicuity was greater with DWMRI than with T2-TSE MRI for the two observers (P = 0.0034 and P = 0.0007). CONCLUSION: DWMRI shows high sensitivity and specificity for the diagnosis of perianal abscesses and helps discriminate between an abscess and inflammatory mass. Conspicuity of fistulas-in-ano is greater with DWMRI than with T2-weighted TSE MRI. KEY POINTS: • DWMRI can differentiate between pelvic abscess and inflammatory mass. • DWMRI helps avoid gadolinium-chelate administration in patients with a suspected fistula-in-ano. • DWMRI provides high degrees of conspicuity for fistula-in-ano. • Conspicuity of fistulas is better with DWMRI imaging than with T2-TSE-weighted MRI.