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Published on: June 18, 2021
CT perfusion and delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage: a systematic review and
Charlotte H P Cremers1, Irene C van der Schaaf2, Emerens Wensink1
1Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.
Insights
CT perfusion (CTP) can diagnose delayed cerebral ischemia (DCI) after subarachnoid hemorrhage but cannot predict it. Standardizing CTP methods is crucial for reliable DCI diagnosis and treatment.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Delayed cerebral ischemia (DCI) is a serious complication following subarachnoid hemorrhage (SAH).
- Current diagnosis of DCI relies on exclusion and delayed imaging.
- A diagnostic tool is needed for timely DCI management.
Purpose of the Study:
- To systematically review the utility of CT perfusion (CTP) in predicting and diagnosing DCI.
- To evaluate CTP parameters like cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and time-to-peak (TTP) in DCI.
Main Methods:
- Systematic review of PubMed, Embase, and Cochrane databases.
- Inclusion of eleven studies with 570 patients.
- Analysis of CTP parameters in patients with and without DCI.
Main Results:
- On admission, no significant differences in CTP parameters were observed between patients who developed DCI and those who did not.
- During the DCI time-window (4-14 days post-SAH), decreased CBF and increased MTT were associated with DCI.
- CTP perfusion thresholds showed moderate and variable test characteristics across studies.
Conclusions:
- CTP is valuable for diagnosing DCI but not for its prediction.
- Standardization of CTP measurement methods after SAH is necessary.
- Optimization and validation of CTP perfusion thresholds are required for improved DCI diagnosis.
Abstract:
Delayed cerebral ischemia (DCI) is at presentation a diagnosis per exclusionem, and can only be confirmed with follow-up imaging. For treatment of DCI a diagnostic tool is needed. We performed a systematic review to evaluate the value of CT perfusion (CTP) in the prediction and diagnosis of DCI. We searched PubMed, Embase, and Cochrane databases to identify studies on the relationship between CTP and DCI. Eleven studies totaling 570 patients were included. On admission, cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and time-to-peak (TTP) did not differ between patients who did and did not develop DCI. In the DCI time-window (4 to 14 days after subarachnoid hemorrhage (SAH)), DCI was associated with a decreased CBF (pooled mean difference -11.9 mL/100 g per minute (95% confidence interval (CI): -15.2 to -8.6)) and an increased MTT (pooled mean difference 1.5 seconds (0.9-2.2)). Cerebral blood volume did not differ and TTP was rarely reported. Perfusion thresholds reported in studies were comparable, although the corresponding test characteristics were moderate and differed between studies. We conclude that CTP can be used in the diagnosis but not in the prediction of DCI. A need exists to standardize the method for measuring perfusion with CTP after SAH, and optimize and validate perfusion thresholds.
