Mesoscale CISS imaging for the detection of dural defects in spinal CSF leaks: A retrospective case series

OBJECTIVE: This retrospective, single-center, descriptive case series evaluates early adoption of a two-stage spine MRI protocol incorporating high-resolution, three-dimensional mesoscale constructive interference in steady state (meso-CISS) for targeted cerebrospinal fluid (CSF) leak localization. BACKGROUND: Spontaneous intracranial hypotension (SIH) results from CSF leaks at the spinal canal, yet precise localization of dural defects remains challenging. Although fat-saturated heavily T2-weighted magnetic resonance (MR) myelography (HT2-MRM) is sensitive to spinal longitudinal extradural CSF collections (SLECs), it does not reliably localize the leak site. METHODS: Thirty-six consecutive patients with suspected SIH underwent a standardized total spine MRI protocol, including three-dimensional HT2-MRM for SLEC screening at Barnes-Jewish Hospital/Washington University School of Medicine between December 2023 and November 2025. In 11 SLEC-positive cases, meso-CISS was performed for targeted high-resolution leak localization. RESULTS: Among the 10 patients with SIH with interpretable meso-CISS imaging, findings consistent with dural defects were visualized in six (0.5-8 mm in size), with additional supportive features suggestive of dural defects identified in three patients. Compared with HT2-MRM, meso-CISS provided higher spatial detail, allowing clearer delineation of dural defects. CONCLUSION: A two-stage spine MRI protocol incorporating HT2-MRM and meso-CISS may aid in the noninvasive localization of dural defects in SIH. Meso-CISS provides high spatial resolution for visualization of small dural defects and associated pathology. Larger studies are required to clarify how this approach may be incorporated into existing diagnostic workflows for spinal CSF leak localization.