Acquisition of susceptibility-sensitive sequences for central vein sign detection: A systematic review of MRI protocols

Background: The central vein sign (CVS), detected through susceptibility-sensitive MRI sequences, is increasingly recognized as a reliable biomarker distinguishing Multiple Sclerosis from mimickers. However, variability in MRI protocols limits reproducibility and clinical integration. Purpose: To systematically review susceptibility-sensitive MRI protocols used in CVS research, aiming to identify standardized approaches and improve reproducibility. Data sources: A comprehensive search was performed in PubMed/MEDLINE, Scopus, and Web of Science, and the reference lists of pertinent meta-analyses. Study selection: Original English-language studies on brain MRI CVS detection in MS, neuroinflammatory conditions and common mimickers, excluding non-original research and non-English articles. Studies were selected following PRISMA guidelines. Ultimately, 94 studies were included in the final review. Data analysis: MRI sequence types and parameters were systematically extracted and analyzed. Data synthesis: Susceptibility-weighted imaging (SWI), 3D T2* EPI, and SWAN were commonly used, with considerable variability in imaging parameters. Many studies did not report essential protocol specifics, limiting reproducibility and comparability across studies. Comparative data on SWI versus 3D T2* EPI at standard clinical field strengths (1.5T and 3T MRI) remain insufficient, creating uncertainty about which sequence provides superior sensitivity for CVS detection. Limitations: Variability in study designs, exclusion of non-English studies, and potential publication bias. Conclusions: There is substantial variability in MRI protocols for CVS detection, emphasizing the need for standardization. Further research comparing susceptibility-sensitive sequences is needed.