The Probable Etiology Of The Hyperdensity On Immediate Brain CT Following Cerebral Angiography In Patients With Cerebral Infarction

Objective To investigate the probable etiology of the hyperdensity on immediate brain CT following cerebral angiography in patients with cerebral infarction.Methods Thirty-four consecutive patients with cerebral infarction who underwent immediate brain CT following cerebral angiography were included in our study. If the immediate CT showed any new finding, a repeat CT was performed within24h after the first CT scan. The patients were further divided into two groups:the hyperdense group and non-hyperdense group according to CT findings. Lumbar puncture was underwent in some of the patients within24h after cerebral angiography. The measurement of the concentration of iopromide in our patients’cerebrospinal fluid (CSF) was performed with ultraviolet spectrophotometry. CT perfusion was performed within three days after cerebral angiography to investigate the homodynamic features in the hyperdense and infarcted lesion.Results Among34patients,15(44%) had hyperdense areas on the immediate brain CT following cerebral angiography. There was no difference in the baseline characteristics including age, gender, hypertension, diabetes, heart disease and hyperlipidemia between the hyperdense group and non-hyperdense group. Non-enhanced CT scan obtained just after cerebral angiography shows various kinds of abnormal findings including cortical contrast enhancement (n=3), corona radiata contrast enhancement (n=2), basal ganglia contrast enhancement (n=6), and a mixed pattern (n=4). Of the15hyperdense patients, it is frequent between two and three weeks after symptom onset. The mean dose of iopromide solution during cerebral angiography in the hyperdense group and non-hyperdense group was104.0±9.5ml and89.2±8.3ml,respectively; the mean dose of contrast agent was significantly higher in the hyperdense group than in the non-hyperdense group. The incidence of the hyperdense lesion on brain CT was higher in the patients with the volume of contrast>100ml than the patients with the volume of contrast≤100ml (81.8%vs26.1%;P<0.05). The concentration of iopromide of CSF in the hyperdense group and non-hyperdense group was209±50ug/ml and29±6ug/ml, respectively; the concentration of iopromide of CSF was significantly higher in the hyperdense group than non-hyperdense group(P<0.05). CTP show that a significantly decreased CBV and CBF, a significantly prolonged MTT and TTP in the infarcted lesion compared with that of the contralateral region both in the hyperdense group and non-hyperdense group (P<0.05); but a significantly elevated CBV and decreased CBF, a significantly prolonged MTT and TTP within the hyperdense lesion compared with that of the contralateral region.Conclusions The hyperdensity on immediate brain CT following cerebral angiography is a fairly common occurrence. The hyperdensity on immediate brain CT following cerebral angiography probably due to the blood-brain barrier disruption followed by contrast media leakage. Contrast neurotoxicity and regional angiogenesis are the two possibly factors influencing BBB permeability. The elevated CBV within the hyperdense lesion in the CTP maps indicates CBV is a sensitive parameter reflecting the hyperdense lesion on brain CT following cerebral angiography in patients with cerebral infarction.