CLINICAL ARTICLE Acute perfusion changes after spontaneous SAH: a perfusion CT study Alfonso Lagares & Marta Cicuendez & Ana Ramos & Elena Salvador & Jose F. Alén & Ariel Kaen & Luis Jiménez-Roldán & J. M. Millán Received: 31 May 2011 / Accepted: 21 December 2011 / Published online: 12 January 2012 # Springer-Verlag 2012 Abstract Background Perfusion computed tomography (CT) is a rap- id technique that allows the measurement of acute distur- bances in local and global cerebral blood flow in patients suffering stroke and spontaneous subarachnoid haemor- rhage (SAH). The purpose of this study was to establish the relationship between different measures of brain perfu- sion made on dynamic-contrast CT reconstructions per- formed as soon as SAH has been diagnosed and the severity of the bleeding determined by the clinical grade, the extent of the bleeding and the outcome of the patients. Methods After the diagnosis of SAH by conventional CT, a perfusion CT was performed before CT angiography. All imaging studies were performed on a six-slice spiral CT scanner. All images were analysed using perfusion software developed by Philips, which produces perfusion CT quan- titative data based on temporal changes in signal intensity during the first pass of a bolus of an iodinated contrast agent. Measurements of mean transient time (MTT), time to peak (TTP), cerebral blood volume (CBV) and cerebral blood flow (CBF) in volumes of interest corresponding to territories perfused by the major cerebral arteries were per- formed. Different data regarding severity of the bleeding— such as level of consciousness, amount of bleeding in con- ventional CT—were collected. All poor-grade patients received a ventriculostomy catheter so that ICP recordings were obtained. Also, the occurrence of delayed cerebral ischaemia (DCI) was recorded. Outcome was assessed by the Glasgow Outcome Scale 6 months after the bleeding. For statistical analysis, non-parametric correlations between variables were performed. Findings Thirty-nine patients have been included in the study since January 2007. In SAH patients there are increasing perfusion abnormalities as the severity of the bleeding increases. The most affected perfusion parameters are TTP and MTT, as they significantly increase with the clinical se- verity of the bleeding and the total volume of bleeding (P < 0.01, Spearman’ s Rho). When average MTT time is increased over 5.9 s there is a 20-fold (95% CI 0 2.1-182) risk of poor outcome. All patients presenting this MTT time suffered from DCI. This value has a positive predictive value of 100% for DCI and 90% for a poor outcome. Conclusions SAH causes cerebral blood flow abnormalities even in the acute phase of the illness, consisting mainly of an increase in circulation times (TTP and MTT), which are correlated with the severity of the bleeding. Keywords Subarachnoid haemorrhage . Cerebral blood flow . Perfusion CT . Cerebral aneurysm . Outcome Introduction Subarachnoid haemorrhage (SAH) is still associated with high morbidity and mortality despite technical advances in the treatment of cerebral aneurysms and new discoveries in the treatment of delayed cerebral ischaemia due to vaso- spasm. In fact the severity of the initial bleeding, expressed by the disturbance of the level of consciousness and the amount of bleeding in the initial computed tomography A. Lagares (*) : M. Cicuendez : J. F. Alén : A. Kaen : L. Jiménez-Roldán Department of Neurosurgery, Hospital 12 de Octubre, Crta de Andalucia km 5.4, Madrid 28041, Spain e-mail: algadoc@yahoo.com A. Ramos : E. Salvador : J. M. Millán Department of Neuroradiology, Hospital 12 de Octubre, Crta de Andalucia km 5.4, Madrid 28041, Spain Acta Neurochir (2012) 154:405–412 DOI 10.1007/s00701-011-1267-z