Computed tomography enterography predicts surgical-free survival in symptomatic stricturing Crohn’s disease. Duan M, Guan B, et al. Abdominal Radiology (2022) 47:3414-3423.

Stricturing in Crohn’s disease (CD) is a complication that affects more than 50% of CD patients in their lifetime. Strictures in CD are initially due to inflammation, but some strictures can develop histologic changes that lead to fibrostenosing lesions. Current medical therapies for CD are aimed at reducing inflammation rather than treating the fibrosis. The treatment for strictures generally requires surgical intervention. Recently, medications such as anti-tumor necrosis factors have been found to help maintain clinical remission and avoiding intestinal resection in patients with stricturing CD, likely by delaying the formation of fibrostenotic changes. Currently determining the degree of inflammation and presence of fibrosis requires tissue sampling, with no reliable non-invasive methods to assess these changes. This study aimed to use CT enterography to assess pathologic changes in symptomatic stricturing Crohn’s disease and to use these findings to predict surgical risks. CT enterography variables assessed included mucosal enhancement, mural stratification, wall enhancement, comb sign, lymphadenopathy, thick non-enhancing wall, bowel wall thickness, luminal diameter and upstream lumen. Bowel wall thickness less than 5.9 mm, luminal stenosis greater than 3.35 mm, and upstream lumen less than 27.5 mm were found to be independent predictors of surgical free survival for symptomatic stricturing CD patients. Histopathological analysis of bowel wall in these patients showed bowel wall muscular hypertrophy was significantly correlated with luminal stenosis and with a combination of other CT enterography variables.

Routine contrast-enhanced CT is insufficient for TNM-staging of duodenal adenocarcinoma. Litjens G, van Laarhoven CJM, et al. Abdominal Radiology (2022) 47:3436-3445.

Duodenal adenocarcinoma is a rare malignancy, accounting for less than 1% of all gastrointestinal tract tumors. The incidence is increasing, nearly doubling in the United States in the last 20 years. Surgical resection in the only potentially curative treatment for duodenal adenocarcinoma. Therefore, adequate staging in duodenal adenocarcinoma is crucial for determining patient prognosis and treatment planning. The authors of this study analyzed the performance of routine contrast enhanced CT for TNM staging and resectability of duodenal adenocarcinoma, and compared to intraoperative and pathological findings, and follow up FDG-PET/CT. The study found that 13% of duodenal adenocarcinomas were missed on CECT. The correct T-stage was assigned in 54% of patients, the correct N-stage was assigned in 42% and correct M-stage in 81% of patients. T-stage was underestimated in 27%, the sensitivity for detecting lymph node metastasis was only 24% and specificity was 78%. Curative surgery was aborted in 19% of patients due to finding unexpected local invasion or metastases. These findings demonstrate that routine CECT is insufficient for staging and determining resectability in patients with duodenal adenocarcinoma.

Dynamic contrast-enhanced and diffusion-weighted MR imaging in early prediction of pathologic response to neoadjuvant chemotherapy in locally advanced gastric cancer. Li J, Yan LI, et al. Abdominal Radiology (2022) 47:3394-3405

Gastric cancer is the third leading cause of cancer-related mortality worldwide, and many patients are staged as locally advanced gastric cancer at the time of first hospitalization. Locally advanced gastric cancer has a poor prognosis with a 5-year survival of only 26%. Previous studies have shown that neoadjuvant chemotherapy improves surgical outcomes and prognosis, but response is variable and patients response to neoadjuvant chemotherapy has been shown to be a key indicator of prognosis. This study investigated the efficacy of diffusion-weighted imaging and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for the early prediction of the pathologic response to neoadjuvant chemotherapy in patients with locally advanced gastric cancer. Patients with locally advanced gastric cancer received an MRI prior to undergoing neoadjuvant chemotherapy and radical gastrectomy. Patients were labeled as neoadjuvant chemotherapy responders or non-responders by tumor regression grading. The two groups were compared for apparent diffusion coefficients and DCE-MRI kinetics. The authors found that both diffusion weighted imaging and DCE-MRI can effectively predict the pathologic response to neoadjuvant chemotherapy in locally advanced gastric cancer, with ADC being the most valuable imaging parameter.

Multiparametric MRI-based Radiomics approaches on predicting response to neoadjuvant chemoradiotherapy (nCRT) in patients with rectal cancer. Cheng Y, Luo Y, et al. Abdominal Radiology (2021) 46: 5072-5085

Neoadjuvant chemoradiotherapy followed by radical resection has a pathologically complete response in one-fifth of patients and can reduce surgery related morbidity. However, response to neoadjuvant chemoradiation is variable, making preoperative evaluation of nCRT response vital for clinical decision making. Currently, assessment of nCRT response is impossible on pre surgery MRI due to lack of reliable markers, making post-operative evaluation the current standard. This study aimed to assess the ability of pre nCRT MRI radiomics features to predict response to nCRT in patients with rectal cancer. For predicting good response the authors found the CEA and CA19-9 levels as the most important clinical factors. For predicting pathologic complete response CEA, length and thickness of tumor were selected as the most predictive factors. Using these and other factors a predictive model was developed that achieved prediction efficacy with area under the curve of 0.918 in the training cohort and 0.912 in the validation model for predicting good response to neoadjuvant chemoradiation, and area under the curve of 0.959 for the training cohort and 0.912 for the validation cohort in predicting pathologic complete response. These findings show MRI-based radiomics should be considered a promising tool for aiding treatment decision making in patients with locally advanced rectal cancer.

MRI features of signet ring rectal cancer. Suthar M, Baheti AD, et al. Abdominal Radiology. (2021) 46: 5536-5549.

Signet ring rectal cancer is a rare subtype of rectal adenocarcinoma with a poor prognosis due to a high tendency for lymphatic, vascular, and perineural invasion. Patients often present with locally advanced or metastatic disease due to the submucosal growth of this cancer type leading to a delay in symptoms. This study evaluated the MRI features of SRRC and correlated the imaging findings with outcomes. 97 patients with SRRC who underwent rectal MRI were retrospectively reviewed for features including tumor morphology, T2 signal, length, location, growth pattern, nodal status, extramural vascular invasion, metastases, and chemotherapy response. These imaging features were then correlated with risk of metastatic or recurrent disease, disease-free survival and overall survival. The authors found that common imaging features include T2-hyperintense signal (63% of patients), infiltrative growth pattern (76% of patients), positive circumferential resection margin on MRI (84% of patients), presence of EMVI (51% of patients), and advanced T and N stage (97 and 84% of patients). The peritoneum and lymph nodes were found to be the most common site of metastases. Elevated serum CEA, positive MR CRM status, extramesorectal adenopathy and advanced N stage had statistically significant predictive value for recurrence or metastases. Elevated serum CEA levels and intermediate T2 signal showed significant independent association with poor overall survival, and advanced N stage showed significant independent association with worse disease-free survival. These findings highlight MRI as a useful tool to diagnose SRRC given the distinct MRI features and clinical features.