Artikel
The value of perfusion computed tomography in predicting clinically relevant vasospasm in patients with aneurysmal subarachnoid hemorrhage
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Veröffentlicht: | 4. Juni 2012 |
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Gliederung
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Objective: Delayed cerebral ischemia due to vasospasm remains one of the most severe complications after aneurysmal subarachnoid hemorrhage (SAH) that may lead to death and disability. We evaluated a semi-quantitative and visual analysis of perfusion computed tomography (PCT) as a predictor of clinically relevant vasospasm (CRV) in patients with aneurysmal SAH.
Methods: After receiving approval from the Institutional Review Board of the University of Greifswald, we prospectively collected and evaluated the data of all patients admitted with aneurysmal SAH to the University Hospital in Greifswald between May 2006 and May 2008. 44 patients were enrolled yielding complete data sets for 38 patients, which were analyzed. 145 PCT scans were evaluated. PCT, clinical examination and transcranial Doppler ultrasound (TCD) were performed on days 3, 7, 10 and 14 after hemorrhage. Cerebral blood flow (CBF), cerebral blood volume (CBV) and time to peak (TTP) were analyzed semi-quantitatively using 6 regions of interest (ROIs). Also, PCT scans were analyzed visually for signs of cerebral hypoperfusion. CRV was defined as secondary cerebral infarction (CI) seen on cranial computed tomography (CCT) scans and/or delayed neurological deterioration (DND).
Results: CI occurred in 13 (34.2%) and DND in 11 patients (28.9%). TTP had a sensitivity of 90% and a specificity of 72% (cutoff value: 0.963) as predictor for CI, when performing TCD as pretest. TTP's sensitivity as predictor for DND was 90% with a specificity of 61.1% (cutoff value: 0.983). Applying TCD as pretest did not influence the diagnostic value of TTP in predicting DND. Visual analysis of TTP showed a negative predictive value (NPV) of 100% with a positive predictive value (PPV) of 52% for CI and a NPV of 84.6% with a PPV of 25% for DND. Cerebral blood flow (CBF) and cerebral blood volume (CBV) could not be shown to be useful parameters in early prediction of CRV.
Conclusions: TTP is a sensitive and specific perfusion parameter in predicting CI and DND in patients with SAH. Its use in the clinical setting may optimize the early treatment of patients at risk for vasospasm before the onset of clinical deterioration, especially when combined with TCD. To our knowledge this is the first study to identify cutoff values for interhemispheric TTP-differences using a semi-quantitative analysis. Further investigation in a larger patient population is required.