Morphological Study Of Middle Cerebral Artery Aneurysm By Computed Tomography Angiography (CTA)

BACKGROUNDIntracranial aneurysms have been the aim of many researchers, but despite findingmultiple correlations between aneurysm rupture and risk factors, their study stillremains limited. Morphological parameters of an aneurysm for predicting their riskfor rupture have been studied by different researchers since past few decades but stillno definitive predictors have been defined which can predict risk for rupture on itsown. However a lot of knowledge about the aneurysm has evolved from these studies.Since morphology of cerebral aneurysms have been considered as a potentialsurrogate of rupture, in this study of ours we have also studied on variousmorphological parameters as defined by many researchers in their study in the past.Among many proposed morphological parameters several indices have shown its linkto establish as a descriptor for the risk of rupture of an aneurysm. In this study, wehave done study on image based model obtained from3D CTA and compared different morphological indices in their significance for describing the risk of rupturein a given aneurysm.OBJECTIVETo study morphological characteristics of middle cerebral artery (MCA)aneurysms by computed tomography angiography (CTA).METHODThe study was done in patients visiting The First Hospital of Jilin University fromJanuary2011to January2013.A total of62patients with aneurysm were selectedwhere27unruptured aneurysms were taken from26patients and36rupturedaneurysms from36patients. Of the entire population11patients had bilateral MCAaneurysms and rest other patient had single or multiple aneurysms. Only lesions inmiddle cerebral artery are taken into account, even if the patient had severalaneurysms in other intracranial arteries. Patients with aneurysm other than sacculartype like fusiform, mycotic were excluded from this study. Since every patient’smedical record including past and present illnesses, radiological examinations,treatments, and outcomes are documented electronically in the hospital computersystem PACS (Picture Archiving and Communication System), this system providesvalid information for retrospective analysis. All morphological parameters wereobtained from CTA derived module and were subjected to various statistical analysisfor its significance in defining risk of rupture for a given aneurysm. RESULTSVarious morphological parameters were proven to be statistically significant inpredicting risk of rupture for an aneurysm.1. Size ratio (SR) proves to be the only independent and most significantmorphological parameter for predicting risk for rupture. SR from various statisticalanalysis yields a result showing its statistical significance (p≤0.001) and AUC (0.78).2. Among other parameters maximum height of aneurysm (Hmax)(p≤0.001, AUC0.78), aneurysm depth (Hpr)(p≤0.001, AUC0.77), aspect ratio (AR)(p=0.002, AUC0.73) and aneurysm volume (p≤0.001, AUC0.75) shows its promise towardspredicting risk for rupture of an aneurysm. However these parameters could not retainthemselves as independent indices in defining risk for rupture when logistic regressionanalysis was done.3. Both the ruptured and unruptured aneurysms were found to be more commonin female with more predilections for the right side. They were more common in51-60age groups with the mean age of distribution being55.59year for unrupturedaneurysms and52.56year for ruptured aneurysms.CONCLUSIONComputed tomography angiography (CTA) is a very useful tool in predicting riskof rupture for a given aneurysm based on various morphological parameters as defined.Among all SR (size ratio) found to be the most important and significantfactor in evaluating the risk of rupture in a given aneurysm.