gms | German Medical Science

Objective: The occurrence of cerebral vasospasm (CVS) constitutes a major complication after spontaneous subarachnoid haemorrhage (sSAH) and is associated with unfavourable outcome. CT perfusion imaging (CTP) is known to verify suspected CVS in SAH patients, while causing considerable radiation exposure. Literature regarding routine use of CTP in the setting of SAH is still limited. This study analyses the value of routinely performed CTP to improve early identification of CVS and to prevent CVS related cerebral infarction.

Methods: We performed a 3-year retrospective analysis of sSAH patients who underwent CTP imaging. All patients received invasive monitoring for intracranial pressure and cerebral oxygenation (PBrO2). Transcranial Doppler sonography (TCD) was executed daily. According to our own treatment protocol for unconscious patients with SAH, CTP was performed routinely every 4 days and in case of suspected CVS, when a sudden decrease of PBrO2 (<15mmHg) or increase of the mean flow velocity (>150cm/s) was detected. CTPs were classified as routine (rCTP) or symptomatic (sCTP).If cerebral malperfusion was observed in CTP imaging, a diagnostic angiography was performed. Angiographically confirmed CVS was treated by endovascular rescue therapy. Clinical, radiographic and demographic data were collected.

Results: During the study period, 213 CTPs (136 rCTPs and 77 sCTPs) were carried out in 65 patients. The rate of new onset of cerebral malperfusion was significantly higher in sCTPs (49%) than in rCTPs (20%), while the rate of angiographic confirmation of CVS was similar in both groups (84% vs. 74%). In 27 cases (20%), rCTP led to a clinical response. Endovascular rescue therapy was performed after 30 sCTPs and 21 rCTPs. A 48h follow-up CT revealed CVS related cerebral infarction after 19 sCTPs (25%) and 14 rCTPs (10%). Multivariate logistic regression analysis revealed a higher probability for new onset of malperfusion in rCTP in those patients who already developed cerebral infarction during the previous clinical course.

Conclusion: Routine CTP in sSAH patients is able to identify cerebral malperfusion, which is not assessable by established clinical diagnostics. However, despite routinely performed CTP and endovascular rescue therapy, CVS related infarction is still present in some patients. Concerning the effectiveness of rCTP, prospective trials are necessary to evaluate both itspotential benefits and possible adverse effects.