Linear indices of ventricular volume on brain computed tomography as markers of effectiveness of epidural blood patch for spontaneous intracranial hypotension: A case report

Epidural blood patch (EBP) is an effective treatment for spontaneous intracranial hypotension (SIH). However, its effectiveness can only be judged through subjective symptom improvement; no objective markers have been reported. Linear indices of ventricular volume on brain computed tomography (CT) may aid the objective evaluation of the effectiveness of EBP in patients with SIH. A 45-year-old man was hospitalized due to a 3-week history of orthostatic headache, dizziness, and neck pain. He had visited a local emergency department at symptom onset. His neurological examination results were normal and vital signs were stable. Brain magnetic resonance imaging (MRI) revealed pachymeningeal enhancement in both convexities with a small subdural hematoma (SDH). Based on the clinical features and MRI findings, he was diagnosed with SIH complicated by SDH. Non-targeted EBP was performed, first at the lumbar level and subsequently at the thoracic level. Linear indices of ventricular volume, including the Evans' index, frontal-occipital horn ratio, and bicaudate index, were measured through brain CT performed before and after EBP. After lumbar EBP, there was no symptom relief or increase in linear indices of ventricular volume on brain CT. In contrast, the patient's symptoms completely resolved and the linear indices of ventricular volume increased after thoracic EBP. The effectiveness of EBP, which is currently evaluated solely based on changes in symptom severity, can be assessed using linear indices of ventricular volume.