Features and perspectives of MR enterography for pediatric Crohn disease assessment

CT enterography-based radiomics combined with body composition to predict infliximab treatment failure in Crohn's disease

PURPOSE

Accurately predicting the treatment response in patients with Crohn's disease (CD) receiving infliximab therapy is crucial for clinical decision-making. We aimed to construct a prediction model incorporating radiomics and body composition features derived from computed tomography (CT) enterography for identifying individuals at high risk for infliximab treatment failure.

METHODS

This retrospective study included 137 patients with CD between 2015 and 2021, who were divided into a training cohort and a validation cohort with a ratio of 7:3. Patients underwent CT enterography examinations within 1 month before infliximab initiation. Radiomic features of the intestinal segments involved were extracted, and body composition features were measured at the level of the L3 lumbar vertebra. A model that combined radiomics with body composition was constructed. The primary outcome was the occurrence of infliximab treatment failure within 1 year. The model performance was evaluated using discrimination, calibration, and decision curves.

RESULTS

Fifty-two patients (38.0%) showed infliximab treatment failure. Eight significant radiomic features were used to develop the radiomics model. The model incorporating radiomics model score, skeletal muscle index (SMI), and creeping fat showed good discrimination for predicting infliximab treatment failure, with an area under the curve (AUC) of 0.88 (95% CI 0.81, 0.95) in the training cohort and 0.83 (95% CI 0.66, 1.00) in the validation cohort. The favorable clinical application was observed using decision curve analysis.

CONCLUSIONS

We constructed a comprehensive model incorporating radiomics and muscle volume, which could potentially be used to facilitate the individualized prediction of infliximab treatment response in patients with CD.

Prevalence and clinical significance of incidental extra-intestinal findings in MR enterography: experience of a single University Centre

PURPOSE

To determine the incidence and clinical relevance of extra-intestinal incidental findings (IF) in a cohort of patients with proven or suspected Crohn disease (CD) examined with magnetic resonance enterography (MR-E) in a single University Centre.

METHODS

Between January 2018 and June 2019, 182 patients with proven or suspected CD with a planned first MR-E examination, were retrospectively included in this study. Incidental findings were considered as any abnormality identified in the absence of previous clinically suspected or known disease. IF were categorized as unremarkable, benign or potentially relevant findings requiring further imaging or specific treatment.

RESULTS

Of the 182 revised MR-E, extra-intestinal IF were recorded in 70 cases (38.5%); 35 (50%) incidental lesions were recognized as non-significant, 24 (34%) as benign and 11 (16%) as clinically relevant. Moreover, there was a positive correlation between IF and patients' age (p < 0.0001).

CONCLUSIONS

In our experience, a high number of IF (38.5%) was found, with a prevalence that increases with patients' age. Clinically relevant findings were found in 16% of MR-E. This means that MR-E is a useful tool to detect IF, therefore, the presence of a radiologist during the image acquisition is crucial in adding sequences to the examination.

Quantitative Analysis of Apparent Diffusion Coefficient for Disease Assessment in Paediatric Inflammatory Bowel Disease

OBJECTIVE

The aim of the study was to establish an apparent diffusion coefficient (ADC) cut-off value to classify active and non-active lesions in inflammatory bowel disease.

METHODS

We reviewed 167 paediatric magnetic resonance enterographies executed for suspected inflammatory bowel disease by using a 1.5- and 3-T scanner. We assessed the presence and activity of the disease by using morphologic and functional parameters such as the ADC. Each patient could have more than 1 examinations. Quantitative assessment of disease activity in the ADC map was measured placing 3 regions of interest in the areas of highest inflammation and the mean value was calculated, patients without sign of inflammation were assessed at 2 standardised site. Ileocolonoscopy, esophagogastroduodenoscopy, surgery, and video-capsule endoscopy were used as standards of reference.

RESULTS

We enrolled 34 patients and 35 examinations: radiological findings of disease were identified in 29 examinations and 44 lesions were detected. Six patients had negative results and ADC assessment was taken at the terminal ileum and cecum. A total of 56 bowel segments were included in the study. Image analysis revealed 39 active lesions (69.6%) and their ADC values were lower compared to the ones of non-active segments. For each scanner a cut-off value was found (sensitivity: 0.91, specificity: 0.89 for 1.5 T and 0.81 for 3 T). Inter-rater agreement on disease activity between ADC values and magnetic resonance enterography results and between ADC values and the standard of reference were very good.

CONCLUSIONS

ADC can provide a scanner-based quantitative measurement of disease activity.

Preoperative assessment of simple and complex anorectal fistulas: Tridimensional endoanal ultrasound? Magnetic resonance? Both?

PURPOSE

The purpose of the study is to evaluate the diagnostic value of tridimensional endoanal ultrasound (3D-EAUS) and magnetic resonance (MR) in the preoperative assessment of both simple and complex anorectal fistulas.

METHODS

All the patients referred for the treatment of anal fistulas were enrolled in this study and underwent, as preoperative assessment, anamnestic evaluation, clinical examination, and unenhanced and H2O2-enhanced 3D-EAUS and MR. The results of imaging evaluation were compared with surgical findings, considered as reference standard.

RESULTS

During the study period, 124 patients operated on for anal fistulas underwent complete preoperative imaging assessment. Perfect agreement between 3D-EAUS and surgery in the anal fistulas' severity grading was found (K = 1). The fistulas were classified as simple in 68/126 (53.9%) and complex in 58/126 (46.03%) cases, according to fistulas' Parks' classification and the most recent American Guidelines. In both simple and complex anal fistulas, 3D-EAUS did not show a significantly higher accuracy in the evaluation of internal openings, if compared with MR (P = 0.47; McNemar's Chi-square test). In the complex anal fistulas, MR showed a significantly higher accuracy in the evaluation of secondary extensions if compared with 3D-EAUS (P = 0.041; McNemar's Chi-square test), whereas in the simple anal fistulas, no significant difference was found.

CONCLUSION

In the preoperative work-up of patients with anorectal fistulas, 3D-EAUS may represent the first-line diagnostic tool. In cases of fistulas classified as complex by 3D-EAUS, MR may be indicated as adjunctive diagnostic imaging examination, to more carefully describe the fistulas' complete anatomy.

Comparison of patients' tolerance between computed tomography enterography and double-balloon enteroscopy

BACKGROUND

Computed tomography enterography (CTE) and double-balloon enteroscopy (DBE) are widely used in diagnosis of small bowel diseases. Both of these examinations bring discomfort to patients. The aim of this study was to compare patients' tolerance and preference between CTE and DBE.

METHODS

From August 1, 2014 to December 31, 2016, patients with suspected or known small bowel diseases who underwent both CTE and DBE were prospectively enrolled in our study. They were asked to fill out a questionnaire evaluating discomfort of the procedure after each examination.

RESULTS

One hundred and seven patients completed our study. Abdominal distension, painfulness, tenesmus, general discomfort, prolonged duration, difficulty in completing the test, and discomfort after the examination were significantly lower with CTE than with DBE (P<0.001, respectively). Mannitol intake (47.7%), bowel preparation (31.9%), and radiation exposure (15.0%) were regarded as the three most intolerable burdens in CTE. Painfulness (38.3%), bowel preparation (26.2%), and invasiveness (16.8%) were considered as the three most unacceptable parts of DBE. More patients (61.7%) preferred to repeat CTE rather than DBE (P<0.001).

CONCLUSION

Compared to DBE, CTE was a more tolerable and less burdensome examination and enjoyed higher preference by most patients.

Magnetic resonance enterography for the evaluation of the deep small intestine in Crohn's disease

For the control of Crohn's disease (CD) a thorough assessment of the small intestine is essential; several modalities may be utilized, with cross-sectional imaging being important. Magnetic resonance (MR) enterography, i.e., MRE is recommended as a modality with the highest accuracy for CD lesions. MRE and MR enteroclysis are the two methods performed following distension of the small intestine. MRE has sensitivity and specificity comparable to computed tomography enterography (CTE); although images obtained using MRE are less clear compared with CTE, MRE does not expose the patient to radiation and is superior for soft-tissue contrast. Furthermore, it can assess not only static but also dynamic and functional imaging and reveals signs of CD, such as abscess, comb sign, fat edema, fistula, lymph node enhancement, less motility, mucosal lesions, stricture, and wall enhancement. Several indices of inflammatory changes and intestinal damage have been proposed for objective evaluation. Recently, diffusion-weighted imaging has been proposed, which does not need bowel preparation and contrast enhancement. Comprehension of the characteristics of MRE and other modalities is important for better management of CD.