Research Information System
Journal of Neuroradiology, vol.53, no.2, 2026 (SCI-Expanded, Scopus)
Background and Purpose: Chiari types 0 to 1.5, represent a spectrum of developmental hindbrain anomalies that may cause brainstem compression and cerebrospinal fluid (CSF) flow disturbance. This study explored associations between magnetic resonance imaging (MRI) features and clinical findings, specifically CSF flow impedance, tonsillar blackout sign (TBS), obex position, and related clinico-anatomical parameters, across the expanded Chiari spectrum. Methods: A retrospective analysis was performed on 147 patients who underwent advanced MRI imaging at a single institution from 2018 to 2025 with suspected Chiari deformity. Patients were classified by Chiari type based on cerebellar tonsillar descent and obex position. Imaging evaluations included CSF flow, TBS severity, syrinx characteristics, and position of obex relative to the foramen magnum. Anatomical classifications, imaging features, and clinical profiles were systematically correlated using appropriate statistical methods. Results: Higher Chiari types were closely associated with increased CSF flow impedance (p = 0.012), and a greater frequency (p < 0.001) as well as severity (p = 0.014) of TBS. A low-lying obex position was significantly associated with elevated CSF impedance (p < 0.001), higher severity of TBS (p < 0.001), and a greater incidence of syrinx formation (p = 0.04). Although head and neck pain and pain in the upper extremities were the most common clinical findings, no significant correlation was found between Chiari type, obex level and syrinx cavity. A weak correlation was observed between CSF flow impedance and TBS (p = 0.01; r = 0.23). Conclusions: This study highlights the importance of using multiple MRI signs for a comprehensive and individualized assessment of Chiari deformities, moving beyond tonsillar measurements to improve diagnosis, risk stratification, and patient management.