Rajbeer Singh Sangha, MD

Yeo LLL, Paliwal PR, Wakerley B, Khoo CM, Teoh HL, Ahmad A, et al. External Validation of the Boston Acute Stroke Imaging Scale and M1-BASIS inThrombolyzed Patients. Stroke. 2014

Current modalities of imaging and advances in technology have allowed physicians to visualize and locate arterial occlusion with excellent spatial resolution as well as view signs of early parenchymal insult.  The use of this information allows a better assessment of stroke severity and prognosis. The initial Boston Acute Stroke Imaging Scale (BASIS) is one such system that takes into account major arterial occlusion and parenchymal damage regardless of the clinical severity.  The authors of this study looked to validate BASIS and its sister scoring system, the M1-BASIS on pre thrombolysis scan, to determine their value in predicting the functional outcome in AIS patients treated with IV-tPA.

265 patients who underwent CTA of intra and extracranial vasculature before IV-tPA bolus were included in this study.  The results showed that the AUC for NIHSS alone was 0.728 to predict good outcomes while that of NIHSS+BASIS was 0.736.  Analysis showed that the 2 ROC curves were not significantly different.  The AUC for NIHSS + M1-BASIS was improved to 0.779, which was statistically significant (z= -0.1676, p = 0.047) when compared to the purely NIHSS ROC. This shows that M1-BASIS does have an additive effect with the NIHSS scale to prognosticate 3 month outcomes.

A scoring system for AIS must be simple, rapid, reproducible and possible in a variety of clinical settings. Detailed clinical rating instruments are commonly used in the settings of a clinical trial, and while these settings help in determining the efficacy of the instrument, it is often difficult to transition them to everyday practice.  As seen from the results of this study, M1-BASIS classification system correlates well with the clinical severity of stroke and can reliably prognosticate outcome in AIS patients treated with systemic thrombolysis.  Further analysis and evaluation should be performed to develop this score to be included in a paradigm which can be applied in a rapid fashion during AIS.  As technology and the ability of computers to exponentially combine information and perform calculations increases, the stroke community should continue to adapt and utilize these tools from the careful observations and analysis made from our studies.