CT enhancement after prolonged high-dose contrast infusion in the early stage of cerebral infarction.

To demonstrate the BBB break-down on the CT image in the acute stage of cerebral infarction, a 3 hour continuous drip infusion of 200 ml of meglumine amidotrizoate, rather than the conventional bolus injection, was used. In this study, 22 examinations were carried out in 18 patients in whom cerebral infarction due to temporary or permanent obstruction of the cerebral artery was diagnosed by CT and angiography on admission. With each examination, the first CT was obtained prior to contrast infusion, and second immediately after the end of 3 hours of continuous contrast infusion. The EMI number was calculated at 3 regions of interest in the infarction. Within 3 days after stroke episode, 4 out of 5 patients with temporary vascular obstruction demonstrated enhancement, as well as 6 out of 9 patients with permanent vascular obstruction. Between 4 and 14 days after the stroke episode, all of 8 patients showed enhancement. To further clarify the extravasation of the contrast medium during the first 3 days of a cerebral infarction, a third CT scan was performed 3-hrs after finishing the contrast infusion in 4 patients. In these latter patients, blood was sampled at the time of each of the 3 CT series. The EMI number of the blood samples was also measured. In all 4 patients, the Gado's tissue-blood ratio (the EMI number of the CT lesion divided by that of the blood sample) was higher than 17.2% in the second, and higher than 54.7% in the third CT scan. Thus break-down of the BBB which was demonstrated by prolonged contrast infusion is an earlier event in human cerebral infarction than is usually accepted.