The administration of hydrogen sulphide prior to ischemic reperfusion has neuroprotective effects in an acute stroke model.

Emerging evidence has suggested that hydrogen sulfide (H2S) may alleviate the cellular damage associated with cerebral ischemia/reperfusion (I/R) injury. In this study, we assessed using 1H-magnetic resonance imaging/magnetic resonance spectroscopy (1H-MRI/MRS) and histologic analysis whether H2S administration prior to reperfusion has neuroprotective effects. We also evaluated for differences in the effects of H2S treatment at 2 time points. 1H-MRI/MRS data were obtained at baseline, and at 3, 9, and 24 h after ischemia from 4 groups: sham, control (I/R injury), sodium hydrosulfide (NaHS)-30 and NaHS-1 (NaHS delivery at 30 and 1 min before reperfusion, respectively). The total infarct volume and the midline shift at 24 h post-ischemia were lowest in the NaHS-1, followed by the NaHS-30 and control groups. Peri-infarct volume was significantly lower in the NaHS-1 compared to NaHS-30 and control animals. The relative apparent diffusion coefficient (ADC) in the peri-infarct region showed that the NaHS-1 group had significantly lower values compared to the NaHS-30 and control animals and that NaHS-1 rats showed significantly higher relative T2 values in the peri-infarct region compared to the controls. The relative ADC value, relative T2 value, levels of N-acetyl-L-aspartate (NAA), and the NAA, glutamate, and taurine combination score (NGT) in the ischemic core region at 24 h post-ischemia did not differ significantly between the 2 NaHS groups and the control except that the NAA and NGT values were higher in the peri-infarct region of the NaHS-1 animals at 9 h post-ischemia. In the ischemic core and peri-infarct regions, the apoptosis rate was lowest in the NaHS-1 group, followed by the NaHS-30 and control groups. Our results suggest that H2S treatment has neuroprotective effects on the peri-infarct region during the evolution of I/R injury. Furthermore, our findings indicate that the administration of H2S immediately prior to reperfusion produces the highest neuroprotective effects.

Post-Ischemic Bowel Stricture: CT Features in Eight Cases.

OBJECTIVE: To investigate the characteristic radiologic features of post-ischemic stricture, which can then be implemented to differentiate that specific disease from other similar bowel diseases, with an emphasis on computed tomography (CT) features. MATERIALS AND METHODS: Eight patients with a diagnosis of ischemic bowel disease, who were also diagnosed with post-ischemic stricture on the basis of clinical or pathologic findings, were included. Detailed clinical data was collected from the available electronic medical records. Two radiologists retrospectively reviewed all CT images. Pathologic findings were also analyzed. RESULTS: The mean interval between the diagnosis of ischemic bowel disease and stricture formation was 57 days. The severity of ischemic bowel disease was variable. Most post-ischemic strictures developed in the ileum (n = 5), followed by the colon (n = 2) and then the jejunum (n = 1). All colonic strictures developed in the "watershed zone." The pathologic features of post-ischemic stricture were deep ulceration, submucosal/subserosal fibrosis and chronic transmural inflammation. The mean length of the post-ischemic stricture was 7.4 cm. All patients in this study possessed one single stricture. On contrast-enhanced CT, most strictures possessed concentric wall thickening (87.5%), with moderate enhancement (87.5%), mucosal enhancement (50%), or higher enhancement in portal phase than arterial phase (66.7%). CONCLUSION: Post-ischemic strictures develop in the ileum, jejunum and colon after an interval of several weeks. In the colonic segment, strictures mainly occur in the "watershed zone." Typical CT findings include a single area of concentric wall thickening of medium length (mean, 7.4 cm), with moderate and higher enhancement in portal phase and vasa recta prominence.

Gastrointestinal Involvement of Recurrent Renal Cell Carcinoma: CT Findings and Clinicopathologic Features.

OBJECTIVE: To retrospectively evaluate the CT findings and clinicopathologic features in patients with gastrointestinal (GI) involvement of recurrent renal cell carcinoma (RCC). MATERIALS AND METHODS: The medical records were reviewed for 15 patients with 19 pathologically proven GI tract metastases of RCC. The CT findings were analyzed to determine the involved sites and type of involvement; lesion size, morphology, and contrast enhancement pattern; and occurrence of lymphadenopathy, ascites and other complications. RESULTS: The most common presentation was GI bleeding (66.7%). The average interval between nephrectomy and the detection of GI involvement was 30.4 ± 37.4 months. GI lesions were most commonly found in the ileum (36.8%) and duodenum (31.6%). A distant metastasis (80%) was more common than a direct invasion from metastatic lesions. The mean lesion size was 34.1 ± 15.0 mm. Intraluminal polypoid masses (63.2%) with hyperenhancement (78.9%) and heterogeneous enhancement (63.2%) were the most common findings. No patients had regional lymphadenopathy. Complications occurred in four patients, with one each of bowel obstruction, intussusception, bile duct dilatation, and pancreatic duct dilatation. CONCLUSION: GI involvement of recurrent RCC could be included in the differential diagnosis of patients with heterogeneous, hyperenhanced intraluminal polypoid masses in the small bowel on CT scans along with a relative paucity of lymphadenopathy.

Corrosive-Induced Carcinoma of Esophagus: Esophagographic and CT Findings.

OBJECTIVE: The purpose of this study was to evaluate the esophagographic and CT findings of corrosive esophageal cancer. MATERIALS AND METHODS: The records of all patients who presented with corrosive esophageal strictures at one institution between June 1989 and April 2015 were retrospectively identified. The search yielded the records of 15 patients with histopathologically proven esophageal cancer. Esophagograms (13 patients) and chest CT images (14 patients) were interpreted independently by two reviewers. Esophagographic findings included the location of tumor, morphologic type, presence and length of mucosal irregularity, presence of asymmetric involvement, and presence of rigidity. CT findings included presence and type of esophageal wall thickening, pattern of enhancement, presence of periesophageal infiltration, and presence of hilar or mediastinal lymphadenopathy. RESULTS: Esophagography showed that the tumor was involved with the stenotic portion in 10 of the 13 patients (76.9%). The most common morphologic feature was a polypoid mass, in 10 patients. In 12 patients (92.3%), mucosal irregularities were observed; the mean affected length was 4.92 cm. Asymmetric involvement and rigidity were observed in nine patients (69.2%). On CT scans, eccentric wall thickening was observed in 10 of the 14 patients (71.4%), homogeneous enhancement in nine (64.2%), and periesophageal infiltration in 11 (78.5%). CONCLUSION: Esophagography commonly shows corrosive esophageal cancer as a polypoid mass with long-segment mucosal irregularities at the stenotic portion, asymmetric involvement, and rigidity. CT shows eccentric esophageal wall thickening with homogeneous enhancement and periesophageal infiltration, which are suggestive of the development of malignancy in patients with corrosive esophageal strictures.

Computed tomography features and predictive findings of ruptured gastrointestinal stromal tumours.

OBJECTIVES: To evaluate the CT features of ruptured GISTs and factors that might be predictive of rupture through comparison with CTs taken prior to rupture and CTs of non-ruptured GIST. METHODS: Forty-nine patients with ruptured GIST and forty-nine patients with non-ruptured GIST matched by age, gender and location were included. Clinical data including pharmacotherapy were reviewed. The imaging features were analyzed. Prior CT obtained before rupture were evaluated. RESULTS: The most common location of ruptured GIST was small bowel with mean size of 12.1 cm. Ruptured GIST commonly showed wall defects, >40 % eccentric necrosis, lobulated shaped, air density in mass, pneumoperitoneum, peritonitis, hemoperitoneum and ascites (p < 0.001-0.030). Twenty-seven of 30 patients with follow up imaging received targeted therapy. During follow-up, thickness of the tumour wall decreased. Increase in size and progression of necrosis were common during targeted therapy (p = 0.017). Newly developed ascites, peritonitis and hemoperitoneum was more common (p < 0.001-0.036). CONCLUSION: Ruptured GISTs commonly demonstrate large size, >40 % eccentric necrosis, wall defects and lobulated shape. The progression of necrosis with increase in size and decreased wall thickness during targeted therapy may increase the risk of rupture. Rupture should be considered when newly developed peritonitis, hemoperitoneum, or ascites are noted during the follow-up. KEY POINTS: • Ruptured GISTs demonstrate large size, eccentric necrosis, wall defects, and lobulated shape. • Rupture should be considered when peritonitis or hemoperitoneum/adjacent hematoma newly appears. • Progression of necrosis with increase in size increases the risk of rupture.

Endoscopic Complete Remission of Crohn Disease After Anti-Tumor Necrosis Factor-α Therapy: CT Enterographic Findings and Their Clinical Implications.

OBJECTIVE: The purpose of this study was to describe the CT enterographic (CTE) findings after endoscopic complete remission (CR) of Crohn disease in patients treated with anti-tumor necrosis factor-α (anti-TNF-α) and the clinical implications of these findings. MATERIALS AND METHODS: The records of 27 patients with Crohn disease (14 men, 13 women; mean age, 28.4 ± 8.6 [SD] years) who achieved endoscopic (ileocolonoscopic) CR after anti-TNF-α therapy and underwent CTE both before therapy and at endoscopic CR were identified. Two readers independently assessed the frequencies and severities of mural and perienteric CTE abnormalities, generally regarded as active inflammatory findings, in the terminal ileum and colorectum in the endoscopic CR state and compared them with the corresponding findings before anti-TNF-α therapy. The association between the presence of CTE abnormalities in the face of endoscopic CR and patient outcome during subsequent follow-up was investigated. RESULTS: CTE abnormalities were present in the face of endoscopic CR in 11-18 (26-42%) of 43 bowel sections (18 terminal ileum, 25 colorectum), the most frequent being mural hyperenhancement (21-40%) followed by mural thickening (12-16%). Both findings were mild and unaccompanied by other findings. The frequency and severity of mural and perienteric CTE abnormalities were statistically significantly reduced at endoscopic CR compared with the pre-treatment state. Patients with (n = 10) and without (n = 17) CTE abnormalities at endoscopic CR did not significantly differ with respect to Crohn disease aggravation during subsequent follow-up periods averaging 27.4 and 28.5 months (0/10 versus 2/17, p = 0.516). CONCLUSION: More than one-fourth of bowel sections in endoscopic CR after anti-TNF-α therapy had residual CTE abnormalities, predominantly mild mural thickening or hyperenhancement. These findings may not have any clinical significance.

Effect of Reducing Abdominal Compression during Prone CT Colonography on Ascending Colonic Rotation during Supine-to-Prone Positional Change.

OBJECTIVE: To determine the effect of reduced abdominal compression in prone position on ascending colonic movement during supine-to-prone positional change during CT colonography (CTC). MATERIALS AND METHODS: Eighteen consecutive patients who had undergone prone CTC scanning with cushion blocks placed under the chest and hip/thigh to reduce abdominal compression and had confirmed sessile polyps ≥ 6 mm in the well-distended, straight, mid-ascending colon, were included. Radial location along the ascending colonic luminal circumference (°) was measured for 24 polyps and 54 colonic teniae on supine and prone CTC images. The supine-to-prone change ranging between -180° and +180° (- and + for internal and external colonic rotations, respectively), was determined. In addition, possible causes of any ascending colonic rotations were explored. RESULTS: Abdominal compression during prone CTC scanning completely disappeared with the use of cushion blocks in 17 of 18 patients. However, some degrees of ascending colonic rotation were still observed, with the radial location changes of -22° to 61° (median, 13.9°) for the polyps and similar degrees for teniae. Fifty-four percent and 56% of polyps and teniae, respectively, showed changes > 10°. The radial location change of the polyps was significantly associated with the degree of anterior shift of the small bowel and mesentery (r = 0.722, p < 0.001) and the degree of posterior displacement of the ascending colon (r = 0.566, p = 0.004) during supine-to-prone positional change. CONCLUSION: Ascending colonic rotation upon supine-to-prone positional change during CTC, mostly in the form of external rotation, is not eliminated by removing abdominal compression in prone position.

Computed tomography findings for a gastric lymphoepithelioma-like carcinoma: How often does it present as a submucosal mass?

OBJECTIVES: To describe the anatomical location, size, tumour characteristics and morphology on CT of gastric lymphoepithelioma-like carcinoma (LELC) in order to determine the proportion of lesions that present as submucosal masses, and to review the clinicopathological findings. METHODS: This retrospective study reviewed CT images of 186 lesions from 178 patients with LELC. CT morphologies and other findings were also analyzed. Pathology and medical records were reviewed. A pathology slide review of the lesions that presented with submucosal masses was performed. RESULTS: Gastric LELC presenting as a submucosal mass was found in 9.1 %. The most common CT morphology was eccentric wall thickening (67.7 %). On the pathology review, 14/17 submucosal mass lesions (82.4 %) had a central ulceration. 105 lesions were T1/T2 stage (94.1 %), and N0 stage was diagnosed in 66.1 %. Fifty-six of 63 metastatic lymph nodes (LNs) (88.9 %) demonstrated homogeneous enhancement, regardless of size. Male predominance (85.4 %), upper stomach location (45.7 %) and multiplicity (4.5 %) were found. CONCLUSIONS: Gastric LELC presenting as a submucosal mass is only detected in a small portion of all patients, and the most common finding is eccentric wall thickening. Central ulceration and enlarged LNs with homogeneous enhancement are occasionally other features on CT. KEY POINTS: • LELCs as submucosal masses on CT were detected in only 9.1 %. • The most common CT finding was eccentric wall thickening (67.7 %). • Central ulceration and enlarged LNs with homogeneous enhancement might be seen.

MR Enterography for the Evaluation of Small-Bowel Inflammation in Crohn Disease by Using Diffusion-weighted Imaging without Intravenous Contrast Material: A Prospective Noninferiority Study.

PURPOSE: To determine whether magnetic resonance (MR) enterography performed with diffusion-weighted imaging (DWI) without intravenous contrast material is noninferior to contrast material-enhanced (CE) MR enterography for the evaluation of small-bowel inflammation in Crohn disease. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained for this prospective noninferiority study. Fifty consecutive adults suspected of having Crohn disease underwent clinical assessment, MR enterography, and ileocolonoscopy within 1 week. MR enterography included conventional imaging and DWI (b = 900 sec/mm(2)). In 44 patients with Crohn disease, 171 small-bowel segments that were generally well distended and showed a wide range of findings, from normalcy to severe inflammation (34 men, 10 women; mean age ± standard deviation, 26.9 years ± 6.1), were selected for analysis. Image sets consisting of (a) T2-weighted sequences with DWI and (b) T2-weighted sequences with CE T1-weighted sequences were reviewed by using a crossover design with blinding and randomization. Statistical analyses included noninferiority testing regarding proportional agreement between DWI and CE MR enterography for the identification of bowel inflammation with a noninferiority margin of 80%, correlation between DWI and CE MR enterography scores of bowel inflammation severity, and comparison of accuracy between DWI and CE MR enterography for the diagnosis of terminal ileal inflammation by using endoscopic findings as the reference standard. RESULTS: The agreement between DWI and CE MR enterography for the identification of bowel inflammation was 91.8% (157 of 171 segments; one-sided 95% confidence interval: ≥88.4%). The correlation coefficient between DWI and CE MR enterography scores was 0.937 (P < .001). DWI and CE MR enterography did not differ significantly regarding the sensitivity and specificity for the diagnosis of terminal ileal inflammation (P > .999). DWI and CE MR enterography concurred in the diagnosis of penetrating complications in five of eight segments. CONCLUSION: DWI MR enterography was noninferior to CE MR enterography for the evaluation of inflammation in Crohn disease in generally well-distended small bowel, except for the diagnosis of penetration.

Assessment by Using a Water-Soluble Contrast Enema Study of Radiologic Leakage in Lower Rectal Cancer Patients With Sphincter-Saving Surgery.

PURPOSE: This study evaluated the efficacy of a water-soluble contrast enema (WCE) in predicting anastomotic healing after a low anterior resection (LAR). METHODS: Between January 2000 and March 2012, 682 consecutive patients underwent a LAR or an ultra-low anterior resection (uLAR) and were followed up for leakage. Clinical leakage was established by using physical and laboratory findings. Radiologic leakage was identified by using retrograde WCE imaging. Abnormal radiologic features on WCE were categorized into four types based on morphology: namely, dendritic, horny, saccular, and serpentine. RESULTS: Of the 126 patients who received a concurrent diverting stoma, only two (1.6%) suffered clinical leakage due to pelvic abscess. However, 37 patients (6.7%) in the other group suffered clinical leakage following fecal diversion (P = 0.027). Among the 163 patients who received a fecal diversion, 20 showed radiologic leakage on the first WCE (eight with and 12 without a concurrent diversion); 16 had abnormal features continuously until the final WCE while four patients healed spontaneously. Eleven of the 16 patients (69%), by their surgeon's decision, underwent a stoma restoration based on clinical findings (2/3 dendritic, 3/4 horny, 5/7 saccular, 1/2 serpentine). After stoma reversal, only 2 of the 11 (19%) complained of complications related to the rectal anastomosis. CONCLUSION: WCE is helpful for detecting radiologic leakage before stoma restoration, especially in patients suffering clinical leakage after an uLAR. However, surgeons appear to opt for stoma restoration despite the persistent existence of radiologic leakage in cases with particular features on the WCE.

Imaging Features of Primary Tumors and Metastatic Patterns of the Extraskeletal Ewing Sarcoma Family of Tumors in Adults: A 17-Year Experience at a Single Institution.

OBJECTIVE: To comprehensively analyze the spectrum of imaging features of the primary tumors and metastatic patterns of the Extraskeletal Ewing sarcoma family of tumors (EES) in adults. MATERIALS AND METHODS: We performed a computerized search of our hospital's data-warehouse from 1996 to 2013 using codes for Ewing sarcoma and primitive neuroectodermal tumors as well as the demographic code for ≥ 18 years of age. We selected subjects who were histologically confirmed to have Ewing sarcoma of extraskeletal origin. Imaging features of the primary tumor and metastatic disease were evaluated for lesion location, size, enhancement pattern, necrosis, margin, and invasion of adjacent organs. RESULTS: Among the 70 patients (mean age, 35.8 ± 15.6 years; range, 18-67 years) included in our study, primary tumors of EES occurred in the soft tissue and extremities (n = 20), abdomen and pelvis (n = 18), thorax (n = 14), paravertebral space (n = 8), head and neck (n = 6), and an unknown primary site (n = 4). Most primary tumors manifested as large and bulky soft-tissue masses (mean size, 9.0 cm; range, 1.3-23.0 cm), frequently invading adjacent organs (45.6%) and showed heterogeneous enhancement (73.7%), a well-defined (66.7%) margin, and partial necrosis/cystic degeneration (81.9%). Notably, 29 patients had metastatic disease detected at their initial diagnosis. The most frequent site of metastasis was lymph nodes (75.9%), followed by bone (31.0%), lung (20.7%), abdominal solid organs (13.8%), peritoneum (13.8%), pleura (6.9%), and brain (3.4%). CONCLUSION: Primary tumors of EES can occur anywhere and mostly manifest as large and bulky, soft-tissue masses. Lymph nodes are the most frequent metastasis sites.

Inflammatory fibroid polyps of the gastrointestinal tract: a 14-year CT study at a single institution.

PURPOSE: To investigate the computed tomography (CT) features of pathology-proven inflammatory fibroid polyps (IFPs) in the gastrointestinal tract. METHODS: This retrospective series study included 27 patients with pathology-proven IFPs in the stomach (n = 16), small (n = 9), and large (n = 2) intestine, who underwent contrast-enhanced CT. Two radiologists reviewed the CT images of the patients to determine in consensus the long diameter, shape, margin, contour, and growth pattern of the lesions, the presence of an ulcer and overlying mucosal hyperenhancement, the lesion enhancement patterns including the homogeneity and the degree of contrast enhancement, and the presence of intussusception and obstruction. The CT results and clinical data of the gastric and intestinal lesions were compared. RESULTS: The IFPs typically manifested as well-defined (89%), round or ovoid (81%), slightly lobulated-contoured (70%) masses with a purely endoluminal growth pattern (96%) and an overlying mucosal hyperenhancement (67%). Lesion homogeneity and the degree of contrast enhancement varied. The intestinal IFPs were significantly larger (3.5 vs. 2 cm), more symptomatic (82% vs. 19%), and more frequently associated with intussusception (73% vs. 0%) and obstruction (46% vs. 6%) than the gastric lesions (p ≤ 0.027). CONCLUSIONS: The characteristic CT features of IFPs were well-defined, round or ovoid, lobulated-contoured, and endoluminal masses with overlying mucosal hyperenhancement and various enhancement patterns. IFP should be included in the differential diagnosis of patients with a soft-tissue mass in the gastrointestinal tract, especially if a large endoluminal mass in the small intestine is accompanied by intussusception.

Iohexol versus diatrizoate for fecal/fluid tagging during CT colonography performed with cathartic preparation: comparison of examination quality.

OBJECTIVE: We aimed to compare iohexol vs. diatrizoate as fecal/fluid tagging agents for computed tomography colonography (CTC) regarding examination quality. METHODS: Forty prospective patients (M:F = 23:17; 63 ± 11.6 years) received CTC using 50 mL (350 mgI/mL) oral iohexol for tagging. Forty other indication-matched, age-matched, and sex-matched patients who underwent CTC using 100 mL diatrizoate for tagging and otherwise the same technique, were retrospectively identified. Two groups were compared regarding overall examination quality, per-patient and per-segment scores of colonic bubbles (0 [no bubbles] to 5 [the largest amount]), and the volume, attenuation, and homogeneity (untagged, layered, and homogeneous) of the residual colonic fluid. RESULTS: The iohexol group demonstrated a greater amount of colonic bubbles than the diatrizoate group: mean per-patient scores ± SD of 1.2 ± 0.8 vs. 0.7 ± 0.6, respectively (p = 0.003); and rates of segments showing ≥ grade 3 bubbles of 12.9 % (85/659) vs. 1.6 % (11/695), respectively (p = 0.001). Residual colonic fluid amount standardized to the colonic volume did not significantly differ: 7.2 % ± 4.2 vs. 7.8 % ± 3.7, respectively (p = 0.544). Tagged fluid attenuation was mostly comparable between groups and the fluid was homogeneously tagged in 98.7 % (224/227) vs. 99.5 % (218/219) segments, respectively (p = 0.344). Iohexol caused more colonic bubbles when used during cathartic CTC. Otherwise, examination quality was similarly adequate with both iohexol and diatrizoate. KEY POINTS: • When used for tagging, iohexol caused significantly more colonic bubbles than diatrizoate. • The residual colonic fluid amount did not significantly differ between iohexol and diatrizoate. • The quality of fluid tagging was similarly adequate in both iohexol and diatrizoate.

Incremental value of liver MR imaging in patients with potentially curable colorectal hepatic metastasis detected at CT: a prospective comparison of diffusion-weighted imaging, gadoxetic acid-enhanced MR imaging, and a combination of both MR techniques.

PURPOSE: To prospectively compare diagnostic performance of diffusion-weighted (DW) imaging, gadoxetic acid-enhanced magnetic resonance (MR) imaging, both techniques combined (combined MR imaging), and computed tomography (CT) for detecting colorectal hepatic metastases and evaluate incremental value of MR for patients with potentially curable colorectal hepatic metastases detected with CT. MATERIALS AND METHODS: In this institutional review board-approved prospective study, with informed consent, 51 patients (39 men, 12 women; mean age, 62 years) with potentially resectable hepatic metastases detected with CT underwent liver MR, including DW imaging and gadoxetic acid-enhanced MR. Two independent readers reviewed DW, gadoxetic acid-enhanced, combined MR, and CT image sets to detect hepatic metastases. The figure-of-merit (FOM) value representing overall diagnostic performance, sensitivity, and positive predictive value (PPV) for each image set were analyzed by using free-response receiver operating characteristic analysis and generalized estimating equations. RESULTS: There were 104 hepatic metastases in 47 patients. The pooled FOM values, sensitivities, and PPVs of combined MR (FOM value, 0.93; sensitivity, 98%; and PPV, 88%) and gadoxetic acid-enhanced MR (FOM value, 0.92; sensitivity, 95%; and PPV, 90%) were significantly higher than those of CT (FOM value, 0.82; sensitivity, 85%; and PPV, 73%) (P < .006). The pooled FOM value and sensitivity of combined MR (FOM value, 0.92; sensitivity, 95%) was also significantly higher than that of DW imaging (FOM value, 0.82; sensitivity, 79%) for metastases (≤1-cm diameter) (P ≤ .003). DW imaging showed significantly higher pooled sensitivity (79%) and PPV (60%) than CT (sensitivity, 50%; PPV, 33%) for the metastases (≤1-cm diameter) (P ≤ .004). In 47 patients with hepatic metastases, combined MR depicted more metastases than CT in 10 and 14 patients, respectively, according to both readers. CONCLUSION: Gadoxetic acid-enhanced MR and combined MR are more accurate than CT in detecting colorectal hepatic metastases, have an incremental value when added to CT alone for detecting additional metastases, and can be routinely performed in patients with potentially curable hepatic metastases detected with CT.

Diffusion-weighted MR enterography for evaluating Crohn's disease: how does it add diagnostically to conventional MR enterography?

BACKGROUND: Diffusion-weighted imaging (DWI) is a novel technique to evaluate bowel inflammation in Crohn's disease (CD). It is unknown whether and how DWI adds to the accuracy of conventional magnetic resonance enterography (MRE). METHODS: Fifty consecutive adults suspected of CD prospectively underwent clinical assessment, conventional MRE and DWI at b = 900 sec/mm without water enema, and ileocolonoscopy within 1 week. MRE images were interpreted with proper blinding. Forty-four patients finally diagnosed with CD (male:female, 34:10; 26.9 ± 6.1 yr) were analyzed. The per-segment accuracy of MRE for diagnosing active CD was assessed in the terminal ileum, right colon, and rectum using location-by-location matching with endoscopy as the reference standard. RESULTS: The study evaluated 58 bowel segments with deep or superficial ulcers, 34 with aphthae, erythema, or edema only, and 35 without inflammation. Conventional MRE + DWI was more sensitive for bowel inflammation than conventional MRE alone (83% [76/92] versus 62% [57/92]; P = 0.001) largely because of additional detection of aphthae, erythema, or edema. The sensitivities for deep and overt ulcers were similar regardless of DWI, ranging from 88% to 97%. Conventional MRE + DWI was less specific than conventional MRE alone (60% [21/35] versus 94% [33/35]; P < 0.001), mostly because of many false positives in the colorectum. Positive DWI findings in the bowel showing active inflammation on conventional MRE were associated with higher Crohn's disease endoscopic index of severity score (P = 0.021) and deep ulcers (P = 0.01; diagnostic odds ratio, 12). CONCLUSIONS: DWI performed without water enema is not useful for incremental detection of bowel inflammation. DWI may help identify more severe inflammation among bowel segments showing active inflammation on conventional MRE.

Use of liver magnetic resonance imaging after standard staging abdominopelvic computed tomography to evaluate newly diagnosed colorectal cancer patients.

OBJECTIVE: To investigate the impact of liver magnetic resonance imaging (MRI) in staging evaluation of newly diagnosed colorectal cancer patients. BACKGROUND: No clear guidelines regarding how to use liver MRI in evaluating newly diagnosed colorectal cancer. METHODS: We included 863 adults who had newly diagnosed colorectal cancer without concomitant malignancies and received portal-phase contrast-enhanced abdominopelvic computed tomography (CT). Patients who had diminutive indeterminate hypoattenuating ["too-small-to-characterize" (TSTC)] hepatic lesions without other suspicious/indeterminate findings (TSTC-liver-on-CT), metastasis-negative hepatic findings (negative-liver-on-CT), and hepatic lesions suspicious or indeterminate for metastasis excluding TSTC lesions as seen on CT were identified. Per-patient rate of hepatic metastasis unsuspected by CT and the diagnostic yield of liver MRI for such lesions were assessed. RESULTS: There were 261 TSTC-liver-on-CT patients, 464 negative-liver-on-CT patients, and 138 patients with suspicious hepatic findings on CT. Among TSTC-liver-on-CT patients, the rate of hepatic metastasis was 2.2% (5/230, excluding patients without follow-up) and the yield of liver MRI was 3% (3/96). Negative-liver-on-CT patients gave the MRI yield of 0% (0/94). Among negative-liver-on-CT patients, the rate of hepatic metastasis discovered within 6 months of curative surgery was 1.1% (4/350, excluding patients without follow-up) when the liver was cleared by negative CT alone and 2% (2/88, excluding patients without follow-up) when cleared also by negative MRI (P = 0.347). Among the patients who had suspicious hepatic findings on CT, the MRI yield was 25% (19/77). CONCLUSIONS: The diagnostic yield of liver MRI for hepatic metastasis was very low in newly diagnosed colorectal cancer patients who showed TSTC hepatic lesions or metastasis-negative hepatic findings on CT. Staging liver MRI is likely unnecessary for them.

Heterotopic pancreas of the jejunum: associations between CT and pathology features.

PURPOSE: To investigate the computed tomography (CT) features of heterotopic pancreas of the jejunum (HPJ) and to assess their associations with HPJ pathology features. METHODS: In this retrospective series analysis, two radiologists reviewed the CT images of 17 patients with surgically proven HPJ in order to determine in consensus the location, long diameter, margin, shape, contour, and growth pattern of the lesions, the presence of a duct-like structure, the lesion enhancement patterns, including the homogeneity, and the degree of contrast enhancement compared with that of the main pancreas. The pathology features of the surgical specimens were reviewed and their associations with the CT features were assessed. RESULTS: On CT, the HPJs typically appeared as a small (<3 cm), well-defined, ovoid or flat-shaped mass in the proximal jejunum with multiple and tiny lobulations. The growth pattern varied and the duct-like structure was rarely visible. The HPJs mostly appeared to be homogeneous and exhibited hyper- or isoattenuation compared to the main pancreas in the arterial and portal phases. However, these enhancement patterns varied slightly depending on the microscopic composition of the lesions (i.e., acinar vs. ductal predominance). Most HPJs comprised histologically of large acini, some ducts, and small islet cells, and had ductal communication with the jejunum. CONCLUSIONS: HPJs typically manifested as small, well-defined, ovoid or flat-shaped, homogeneous, and well-enhancing masses with a microlobulated contour in the proximal jejunum on CT, and their enhancement patterns associated with their microscopic composition. The pathology features of HPJs generally mimic those of the normal pancreas.

Adenomatous neoplasia: postsurgical incidence after normal preoperative CT colonography findings in the colon proximal to an occlusive cancer.

PURPOSE: To determine the postoperative incidence of adenomatous neoplasia in the colon proximal to an occlusive colorectal cancer where preoperative computed tomographic (CT) colonography findings were normal. MATERIALS AND METHODS: Institutional review board approval, with a waiver of informed consent, was obtained. This observational study included patients with occlusive colorectal cancer who underwent preoperative CT colonography between April 2007 and March 2010 that revealed normal findings (ie, no lesions ≥ 6 mm) in the proximal colon and who underwent postoperative colonoscopy. The primary outcome was postoperative colonoscopic discovery of clinically relevant lesions (ie, nondiminutive [≥ 6 mm] adenomas, advanced adenomas, or cancers) in the proximal colon. The cumulative incidence of clinically relevant lesions in preoperatively normal proximal colon over the postsurgical follow-up time was analyzed by using the Kaplan-Meier method. RESULTS: The final cohort included 204 patients (102 men and 102 women; mean age, 57.3 years ± 11.3 [standard deviation]). At a total of 435 postoperative colonoscopies performed over a median follow-up of 29 months (range, 1-74 months), clinically relevant lesions were detected in the proximal colon in 30 patients: Nonadvanced adenomas were detected in 23 patients, and advanced adenomas were detected in seven patients. The cumulative incidence of clinically relevant adenomatous lesions in the preoperatively normal proximal colon 12 and 18 months after preoperative CT colonography was 8.1% (95% confidence interval [CI]: 3.9%, 12.2%) and 9.6% (95% CI: 5%, 14%), respectively. Clinically relevant adenomatous lesions found in the proximal colon within 18 months of preoperative CT colonography were nonadvanced adenomas in 10 of 15 patients. CONCLUSION: When the portion of the colon proximal to an occlusive cancer is devoid of nondiminutive lesions at preoperative CT colonography, colonoscopy of the proximal colon following cancer resection rarely finds clinically relevant lesions and is unlikely to reveal any lesions requiring immediate removal until routine 1-year postsurgical follow-up. Online supplemental material is available for this article .

Endoscopic and clinical analysis of primary T-cell lymphoma of the gastrointestinal tract according to pathological subtype.

BACKGROUND AND AIM: Little is known about the clinicopathological characteristics of primary gastrointestinal T-cell lymphomas (PGITL). This study evaluated the clinical and endoscopic features of the pathological subtypes of PGITL. METHODS: Forty-two lesions in 36 patients with PGITL were assessed, including 15 enteropathy-associated T-cell lymphomas (EATL), 13 peripheral T-cell lymphomas (PTCL), 10 NK/T-cell lymphomas (NK/TL), and four anaplastic large cell lymphomas (ALCL). RESULTS: PTCL occurred more frequently in the stomach and duodenum and NK/TL more frequently in the small and large intestines (P = 0.009). The endoscopic features of the four subtypes were similar (P = 0.124). Fifteen of 41 lesions (36.6%) were Epstein-Barr virus (EBV) positive, with NK/TL more likely to be EBV positive than the other types (P < 0.001). First endoscopy and first computed tomography (CT) scan indicated that 65.4% and 51.4% of the lesions, respectively, were malignant, and that 43.2% and 42.3%, respectively, were GI lymphomas. The two modalities together correctly diagnosed about half of the lesions before biopsy. Intestinal perforation was associated with small bowel location (P < 0.001) and infiltrative type (P = 0.009), and was more common in NK/TL than in the other subtypes (P = 0.015). Multivariate analysis showed that higher international prognosis index (P = 0.008) and the presence of complications (P = 0.006) were associated with poor prognosis. Survival was poorer in patients with small bowel lesions than with lesions at other locations (P = 0.048). CONCLUSIONS: The four main pathological types of PGITL differed in clinical characteristics. As PGITL was often not diagnosed by initial endoscopic or radiological examination, a high index of suspicion is necessary to ensure its early diagnosis.

Locally advanced rectal cancer: diffusion-weighted MR tumour volumetry and the apparent diffusion coefficient for evaluating complete remission after preoperative chemoradiation therapy.

OBJECTIVE: To evaluate DW MR tumour volumetry and post-CRT ADC in rectal cancer as predicting factors of CR using high b values to eliminate perfusion effects. METHODS: One hundred rectal cancer patients who underwent 1.5-T rectal MR and DW imaging using three b factors (0, 150, and 1,000 s/mm(2)) were enrolled. The tumour volumes of T2-weighted MR and DW images and pre- and post-CRT ADC150-1000 were measured. The diagnostic accuracy of post-CRT ADC, T2-weighted MR, and DW tumour volumetry was compared using ROC analysis. RESULTS: DW MR tumour volumetry was superior to T2-weighted MR volumetry comparing the CR and non-CR groups (P < 0.001). Post-CRT ADC showed a significant difference between the CR and non-CR groups (P = 0.001). The accuracy of DW tumour volumetry (Az = 0.910) was superior to that of T2-weighed MR tumour volumetry (Az = 0.792) and post-CRT ADC (Az = 0.705) in determining CR (P = 0.015). Using a cutoff value for the tumour volume reduction rate of more than 86.8 % on DW MR images, the sensitivity and specificity for predicting CR were 91.4 % and 80 %, respectively. CONCLUSION: DW MR tumour volumetry after CRT showed significant superiority in predicting CR compared with T2-weighted MR images and post-CRT ADC.