gms | German Medical Science

Objective: The acute phase after aneurysmal subarachnoid hemorrhage (aSAH) is associated with a high risk for the formation of early and delayed ischemic and other complications. This leads to a relevant use of diagnostic tools including computer tomography (CT) and fluoroscopy-based imaging, associated with a significant radiation exposure (RE). Since aSAH occurs often in younger patients compared to ischemic stroke, the assessment of RE is a relevant issue in this patient population. The aim of this study was to calculate the average cumulative RE in the acute phase after aSAH and to evaluate its impact on long-term outcome.

Methods: We performed a retrospective analysis of patients with aSAH treated between 2008 and 2018. The radiation dose of every single examination such as CT, CT-angiography (CTA), CT-perfusion (CTP), diagnostic digital subtraction angiography (DSA) and endovascular intervention as a rescue treatment for refractory vasospasm or aneurysm occlusion was calculated. The long-term outcome was assessed according to the modified Rankin scale (mRS) at least 3 months after the ictus, whereat a mRS≤3 was considered as good clinical outcome. The correlation between RE and the aSAH grade, ischemic complications and long-term outcome was evaluated.

Results: A total of 375 patients were included. The mean age was 55.2± 14,3, 65.3% were female. A high grade aSAH (Hunt&Hess I-III) had 64.9% of the patients. The calculated radiation doses per examination were as followed: CT 2 mSv, CTA 3 mSv, CTP 5 mSv, DSA 22 mSv, Coiling 33,5 mSv, dilatation 19 mSv. The average cumulative RE per patient was 76.5 mSv. A higher aSAH-grade was associated with a higher RE (mean 59.3 mSv vs 32.1 mSv, linear regression, p=0.00002). Patients with a better outcome (mRS 0-3 or GOS 4-5) also received significantly lower radiation doses in the acute phase after aSAH (Welch t-test, p=0.00008). Furthermore, dilated patients (Welch t-test, p=0.01), clipped patients (Welch t-test, p=0.02), patients with DCI (Welch t-test, p=0.0008) or with delayed infarction (Welch t-test, p=0.00008) had a significantly higher RE.

Conclusion: This study confirms a significant imaging-related RE in patients with a complication-rich aSAH-course. A meticulous decision-making process and an elaboration of imaging-protocol with lower RE for the deployment of CT and fluoroscopy-based imaging is indicated in the acute phase of aSAH in order to reduce the RE in this patient population.