Early signs of acute middle cerebral artery ischemia in Computerized Tomography and Diffusion Weighted Magnetic Resonance

Stroke is one of the most frequent causes of death and invalidity. The introduction of anticoagulation treatment which improves patients recovery has set new demands for diagnostic neuroimaging. The aim of the study was to assess diagnostic value of computerized tomography in evaluation of early cerebral changes in middle cerebral artery ischemia and application of diffusion weighted magnetic resonance imaging in acute stroke. Computerized tomography was performed in the group of 125 patients with clinical diagnosis of stroke within 12 hours from the onset of symptoms. Follow-up CT was done within 7 days to confirm the presence of ischemic changes. Early abnormalities found on CT scans included: hypo attenuation of lentiform nucleus (ALN), loss of insular ribbon (LIR), hemispheric sulcus effacement (HES) and hyperdense middle cerebral artery sign (HMCAS). These findings were detected in 57.6% of patients examined with CT. Sensitivity of early CT increased from 54,5% within 3 hours after onset of symptoms to 90% in the studies performed within 6 and 12 hours from the onset. Magnetic resonance imaging with diffusion weighted spin echo was performed in 53 patients, who had negative CT examination for acute ischemic changes. Diffusion weighted imaging showed acute ischemic lesions in 92.5% of patients. Findings included one focal lesion in 54.7% patients, 26.4% patients had changes in two cerebral lobes and 11.3% patients had diffuse lesions in three cerebral lobes and basal ganglia. Computerized tomography proved to be a sensitive modality in imaging of middle cerebral artery ischemic lesions. Diffusion weighted imaging in low field MR system is a fast and useful technique for detecting ischemic lesions in early stroke in cases of negative CT findings. (author)