DETECTABILITY OF ACUTE MCA INFARCTIONS BY CT - APPEARANCE OF SIGNS OFISCHEMIA

Purpose: To evaluate the detectability of acute middle cerebral artery (MCA) infarctions by CT with regard to the time interval after sympto m onset and to the infarction size. Analysis of the chronological appe arance of signs of ischaemia. Material and methods: Two examiners retr ospectively and independently evaluated CT scans from 171 patients wit h acute MCA infarctions performed within 24 hours after onset of sympt oms. Results: 92, respectively 87%, of the infarctions were correctly diagnosed. The detection tate did not increase after the first hour af ter onset of symptoms. All MCA infarctions involving the lentiform nuc leus, but only 83% of the infarctions covering <33% of the MCA area, w ere recognised. The hyperdense middle cerebral artery sign (HMCAS) was present in 75% of the infarctions in the first 90 minutes and in 15% from hour 12 to 24. Hypodensity of the lentiform nucleus appeared with in 150 minutes, hypodensity of the convexity cortex at the earliest 60 minutes after onset of symptoms. Conclusions: The detection rate of a cute MCA infarctions corresponds with the infarction size, but does no t significantly change after the first hour after symptom onset.