The diagnostic performance of magnetic resonance imaging (MRI) in the evaluation of breast ultrasound non-mass lesions: a systematic review

Aim: The purpose of this study is to conduct a systematic review of the current knowledge regarding the diagnostic performance of MRI in the investigation of non-mass lesions of the breast. Method: Up to July 2022, PubMed, Scopus, Web of Science, and Embase were searched comprehensively. All studies examining the diagnostic performance of MRI in non-mass lesions were included except review articles, articles published in a language other than English, and case reports or series of cases. A literature review and data extraction were performed by two independent reviewers. A checklist for cross-sectional studies developed by the Joanna Briggs Institute (JBI) was used to assess sources of bias. Results: The systematic review included two studies. If any enhancement is present on MRI, most ultrasound NMLs will exhibit a non-mass-enhancement. We found that the distribution of non-mass enhancement lesions was primarily segmental and regional. The highest number of malignancies is associated with segmental distributions, since 81.8% of the cases with segmental enhancement were ductal carcinomas, specifically DCIS. Conclusion: Non-mass lesions of the US that do not enhance in MRI have a good prognosis. Breast cancer is very unlikely in these cases, so follow-up is acceptable unless there is a suspicion of malignancy on mammography. In cases where regional and segmental enhancement of NMLs occurs on CE-MRI, ductal carcinomas may be present, and a pathological examination is warranted

Role of abbreviated non-contrast-enhanced MR-enterography in the evaluation of Crohn's disease activity and complications as an alternative for full protocol contrast-enhanced study: A systematic review and meta-analysis

Background: Crohn's disease (CD) is a chronic disorder that often starts at a young age and involves periods of remission and relapse. Prompt diagnosis of relapses through screening is crucial due to the potential morbid complications of untreated active inflammation. Magnetic resonance enterography (MRE) is a noninvasive technique to screen for active inflammation. The standard protocol involves intravenous injection of contrast agents with potential side effects. Some abbreviated non-contrast-enhanced MRE protocols are proposed as alternatives for conventional MRE to identify active inflammation. Currently, there is controversy regarding the applicability and accuracy of these protocols. This study aims to describe and compare these protocols and evaluate their accuracy in detecting active inflammation and CD complications. Methods: Results from a systematic search of three databases in August 2022 were queried and screened by abstract and full text. Eligible studies were qualitatively and quantitatively analyzed by diagnostic test accuracy meta-analysis. Results: 59 studies entered the systematic review, and 37 were eligible for meta-analysis. Diffusion-weighted imaging (DWI) and fast T2-weighted (T2w) sequences were most frequently used in abbreviated protocols and showed non-inferior accuracy compared to the full protocol in detecting active inflammation. ADC and qualitative DWI had pooled sensitivity of 90% (CI: 82–95%) and 89% (CI:82–93%) and pooled specificity of 94% (CI: 88–97%) and 89% (CI: 79–94%), respectively for detecting active inflammation. Moreover, T2w and combined T2w+DWI sequences had pooled sensitivity of 80% (CI: 64–90%) and 76% (CI: 61–86%) and pooled specificity of 90% (CI: 80–95%) and 87% (CI: 74 – 94%), respectively. Unenhanced protocols show relatively poor diagnostic accuracy in detecting penetrating complications of CD. Magnetization transfer imaging (MTI) has demonstrated excellent accuracy in detecting fibrosis. High heterogeneity was observed in all subgroups, and accuracy was reported to be highly operator dependent in most studies. Conclusion: An abbreviated protocol consisting of DWI and fast T2w imaging can potentially replace the full protocol MRE. Full protocol MRE will still have its role in identifying penetrating complications. MTI should be indicated in case of suspected fibrostenotic disease