Detection of Early Ischemic Changes in Noncontract CT Using Hounsfield Unit Measurements in Aspects Score
1Department of Radiology, Rambam Health Care Campus Hospital, Israel
2Department of Neurology, Rambam Health Care Campus Hospital, Israel
BACKGROUND AND PURPOSE: The Alberta Stroke Program Early CT Score (ASPECTS) is found to have prognostic value in early stroke and was shown to be a reliable and strong predictor of functional outcome. Here we describe our experience in measurement of Hounsfield unit (HU) values of ASPECTS on initial noncontrast head CT and correlation with the extent of final infarct on follow-up imaging
METHODS: We retrospectively identified 203 patients with acute ischmic stroke that underwent imaging between 2015 and 2017. Those patients presented within 4 hours from symptoms onset, had MCA infarct with occlusion at M1/M2/M3 level, underwent full stroke imaging protocol including non-contrast CT, CTP, CTA and had follow-up CT. All pretreatment CT scans were prospectively scored using a manual technique for HU values in the 10 ASPECTS regions bilaterally and correlated with final ASPECTS at 24 hours. Additionally a control group consistent of 54 patients with clinical suspected ischemic stroke in which all CT examinations were normal including 24 hours follow-up CT
RESULTS: Manual technique showed a statistically significant difference (p<0.001) between affected and non-affected ASPECTS regions. A difference of 2 HU was significantly associated with stroke (p<0.001). In the control group there was no significant difference in HU measurements between the two hemispheres.
CONCLUSIONS: Using measurement of HU values in ASPECTS between the affected and contralateral hemispheres can be integrated into the diagnostic pathway in patients with acute ischemic as a simple algorithm to predict the extent of final stroke and can help physician in patients` care