Masahiro Muto

Background/Objectives: This study examined the clinical utility of diffusion-weighted whole-body magnetic resonance imaging with background body signal suppression (DWIBS) for differentiating infectious from non-infectious aortitis. Methods: The study included 32 patients with suspected inflammatory aortitis who underwent non-contrast computed tomography (NCCT) and magnetic resonance imaging. We evaluated the diagnostic performance of DWIBS using the spinal cord as a reference, NCCT, and their combination. The diagnosis of infectious aortitis was adjudicated based on imaging, clinical, and laboratory findings. We conducted a sensitivity analysis using a stricter definition of infectious aortitis that required both surgical and microbiological confirmation. Results: Fifteen patients were diagnosed with infectious aortitis. The sensitivity, specificity, and areas under the receiver operating characteristic curves were 93.3%, 70.6%, and 0.82, respectively, for NCCT; 93.3%, 76.5%, and 0.85, respectively, for DWIBS; and 86.7%, 94.1%, and 0.90, respectively, for the combination of both modalities. In the sensitivity analysis, the combined DWIBS and NCCT approach demonstrated a specificity of 87.5% and a sensitivity of 70.8%. Conclusions: DWIBS using the spinal cord as a reference appears to be a promising diagnostic tool for differentiating infectious from non-infectious aortitis, especially when combined with NCCT.

Objective: This study aimed to quantify chronological cerebral blood flow (CBF) changes using arterial spin labeling (ASL) magnetic resonance imaging in patients with reversible cerebral vasoconstriction syndrome (RCVS). Background: Quantitative ASL analyses in RCVS have not been well described in the literature. Methods: Quantification of ASL using an automated region‐of‐interest placement software and a 5‐point visual scale of vasoconstriction severity was performed in five RCVS patients. The association between CBF changes and RCVS‐related complications was evaluated. Results: Quantitative ASL revealed variable patterns of decreasing CBF in the first week, followed by subsequent increases. Notably, arterial vasoconstriction paradoxically progressed despite an increase in CBF from the first to the second week; this increase was relatively higher in patients with both cortical subarachnoid hemorrhage and posterior reversible encephalopathy syndrome. Conclusions: Quantitative ASL revealed that CBF initially decreased and subsequently increased, especially in the second week. These changes may serve as surrogate imaging markers for RCVS‐related complications, and could further contribute to understanding the pathology of RCVS.