• Korean Journal of Radiology
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• v.22 no.10
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• pp.1640-1649
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• 2021

Objective: Flattening in the anteroposterior direction (AP flattening) of the terminal ileum (TI) or sigmoid colon (SC) lying across the psoas muscle, on magnetic resonance enterography (MRE), might mimic bowel inflammation in the coronal view. This study investigated the prevalence of AP flattening and the factors associated with its development. Materials and Methods: A total of 364 surgery-naïve patients with Crohn's disease (CD) who had undergone MRE were retrospectively reviewed. AP flattening was defined as a luminal collapse in the anteroposterior direction, with a bowel width in the axial plane < 1/4 of the normal diameter without reduction of bowel width in coronal images. The prevalence of AP flattening of the TI and SC on MRE in patients with bowel segments lying across the psoas muscle was determined. We further compared the rate of AP flattening between MRE and computed tomography enterography (CTE) in a subcohort of patients with prior CTE. The factors associated with AP flattening were analyzed using multivariable logistic regression in a subcohort of patients with endoscopic findings of TI. Results: Three hundred and twenty-two and 363 patients, respectively, had TI and SC lying across the psoas muscle. The prevalence of AP flattening on MRE was 7.5% (24/322) in TI and 5.2% (19/363) in SC. The prevalences were significantly higher on MRE than on CTE in both the TI (7.3% [12/164] vs. 0.6% [1/164]; p = 0.003) and SC (5.8% [11/190] vs. 1.6% [3/190]; p = 0.039). AP flattening of the TI was independently and strongly associated with the absence of CD inflammation on endoscopy, with an adjusted odds ratio of 0.066 (p = 0.003) for the presence versus the absence (reference) of inflammation. Conclusion: AP flattening of the TI or SC lying across the psoas muscle was uncommon and predominantly observed on MRE of the bowel without CD inflammation.

• Investigative Magnetic Resonance Imaging
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• v.18 no.4
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• pp.323-331
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• 2014

Purpose : To assess the usefulness of rectal filling using ultrasonographic gel in patients with lower rectal cancer. Materials and Methods: Twenty five patients with lower rectal cancer were enrolled. High resolution pelvic MR was performed twice before and after gel filling. Independently and retrospectively, two radiologists reviewed each set of MR images using five-grade scales for sphincter involvement, CRM (circumferential resection margin) involvement and depiction of the tumor. Same two radiologists retrospectively performed consensus review of each set of MR images for tumor distance from the anal verge and T&N staging. Results: Tumor depiction scores from MR with gel filling were significantly higher than those of MR without distention (p<0.001). Compared to MR without distension, MR with gel filling had no significant differences in prediction of CRM or sphincter involvement (p>0.05). Distance from the anal verge was significantly different between MR with gel filling and rigid endoscopy ($6.8{\pm}1.6cm$ vs. $5.8{\pm}1.6cm$, p=0.001). There were no significant differences between pathological staging and MR staging with or without gel filling. Conclusion: MR with gel filling improved tumor depiction. And also MR with gel filling revealed same ability for the predictions of CRM or sphincter invasion in patients with lower rectal cancer, comparing with MR without gel filling.