Posterior fossa hematoma: CT perfusion as a tool to reveal occult intracranial hypertension and support surgical decision-making - a case report.

backgroundSpontaneous posterior fossa hematoma is a neurological emergency associated with rapid deterioration from brainstem compression and localized intracranial hypertension. The resulting mass effect can reduce regional perfusion, but these changes are often not fully appreciable on non-contrast CT, and MRI is not always feasible in unstable patients. Invasive intracranial pressure (ICP) monitoring in the posterior fossa could provide direct information on compartmental pressure; however, catheter placement is technically challenging and carries risks including cerebellar hemorrhage, cerebrospinal fluid (CSF) leak, cranial nerve palsy, and brainstem contusion. Consequently, infratentorial ICP monitoring is rarely used, and treatment decisions are based on clinical examination, supratentorial ICP values, and conventional imaging, which may underestimate pressure effects. CT perfusion (CTP) offers a rapid, noninvasive method to assess regional perfusion, detect indirect signatures of occult intracranial hypertension, and identify cerebellar tissue at risk of reversible ischemia. CASE PRESENTATION: A 50-year-old woman with arterial hypertension was found comatose with a Glasgow Coma Scale (GCS) score of 3, mid-mydriatic non-reactive pupils, and absent airway protective reflexes. Non-contrast CT revealed a large right cerebellar hematoma. CT perfusion demonstrated hypoperfusion at the hematoma site, with prolonged time-to-maximum (TMAX) in the surrounding cerebellar parenchyma and reduced cerebral blood flow (CBF) despite preserved cerebral blood volume (CBV), suggesting salvageable tissue. In the absence of large-vessel stenosis, prolonged TMAX was interpreted as most consistent with reduced effective cerebral perfusion pressure, plausibly related to compartmental intracranial hypertension in the posterior fossa. Prolonged TMAX with low CBV was also observed in the ipsilateral cerebral peduncle, indicating localized ischemia likely related to upward transtentorial herniation. The patient underwent emergency external ventricular drain placement and posterior fossa decompression with hematoma evacuation. Follow-up CTP on postoperative day seven showed normalization of perfusion parameters, with improved CBV and CBF and reduced TMAX.

conclusionsThis case illustrates how CTP can complement conventional imaging in posterior fossa hematomas by providing physiological information that is otherwise difficult to obtain invasively. By revealing perfusion patterns consistent with occult compartmental intracranial hypertension and demonstrating viable tissue at risk, CTP may counterbalance prognostic nihilism and support timely surgical decision-making in patients with posterior fossa hematoma.