Detection of Pulsation in Unruptured Cerebral Aneurysms by ECG-Gated 3D-CT Angiography (4D-CTA) with 320-Row Area Detector CT (ADCT) and Follow-up Evaluation Results: Assessment Based on Heart Rate at the Time of Scanning

Abstract

Many epidemiological studies on unruptured cerebral aneurysms have reported that the larger the aneurysm, the higher the risk of rupture. However, many ruptured aneurysms are not large. Electrocardiography (ECG)-gated 3D-computed tomography angiography (4D-CTA) was used to detect pulsation in unruptured cerebral aneurysms. The differences in the clinical course of patients in whom pulsation was or was not detected were then evaluated. Forty-two patients with 62 unruptured cystiform cerebral aneurysms who underwent 4D-CTA and follow-up 3D-CTA more than 120 days later were studied. The tube voltage, tube current, and rotation speed were 120 kV, 270 mA, and 0.35 s/rot., respectively. ECG-gated reconstruction was performed, with the cardiac cycle divided into 20 phases. Patients with heart rates higher than 80 bpm were excluded, so 37 patients with 56 aneurysms were analyzed. Pulsation was detected in 20 of the 56 unruptured aneurysms. Of these 20 aneurysms, 6 showed a change in shape at the time of follow-up. Of the 36 aneurysms in which pulsation was not detected, 2 showed a change in shape at follow-up. There was no significant difference in the follow-up interval between the two groups. The aneurysms in which pulsation was detected were significantly more likely to show a change in shape (P = 0.04), with a higher odds ratio of 7.286. Unruptured aneurysms in which pulsation was detected by 4D-CTA were more likely to show a change in shape at follow-up, suggesting that 4D-CTA may be useful for identifying aneurysms with a higher risk of rupture.