A comparative study of conventional MRI with diffusion weighted imaging in the evaluation of acute cerebral ischaemia

To compare the diagnostic sensitivity of diffusion weighted images with that of conventional magnetic resonance imaging (MRI) techniques in patients presenting within 24 hours of onset of symptoms of acute cerebral ischaemia, a one year prospective study was conducted in the department of radiodiagnosis of Christian Medical College and Hospital, Ludhiana. Patients with signs and symptoms of cerebral ischaemia, presenting within 24 hours of onset were included in the study. MR imaging was performed with 1.5 Tesla system (Signa; GE Medical systems) with echoplanar capability. A total of 40 patients were studied, with majority (80%) in the 40-80 years age group; 52% of patients presented to the hospital after 12 hours of symptom onset. Eight patients presented within three hours of symptoms. In this group of 8 patients conventional MR was positive in only 5 patients (62.5%) while diffusion weighted imaging was positive in all 8 patients. The time of presentation is a crucial factor in determining the therapeutic options for a patient with stroke. Diffusion weighted imaging is more sensitive than conventional MRI in detecting cerebral ischaemic changes in patients presenting less than 24 hours from the onset of symptoms.