頚部・頭蓋内病変に対する3D-CTA撮影方法の工夫

We evaluated various ways of improving the image clarity of three-dimensional CT angiography (3D-CTA) for the diagnosis of cervical and cerebral vascular disease in sixty-seven patients (36 males and 31 females). The mean age was 61.4 years, with a rang of 17 to 89 years. The patients were examined with a helical CT scanner (TCT-X vision GX) after intravenous bolus injection of 90 ml nonionic contrast medium (300 mgI/ml) at the rate of 3ml/sec. Intracranial and cervical 3D-CTA were performed 60 and 12 times, respectively. Our findings were as follows :
1. Reduction of the pre-scanning delay time from 18 to 10 sec after the injection of the contrast medium eliminates much of the cavernous sinus from the image and makes it easier to distinguish the intracavernous internal carotid artery in intracranial 3D-CTA. In cervical 3D-CTA, reduction of the pre-scanning delay time from 15 to 9 sec delays imaging of the jugular vein and makes it easy to distinguish the bifurcation of the common carotid artery.
2. A subtraction image on 3D-CTA is useful for detecting of vascular lesions adjacent to bone, such as lesions on the internal carotid artery.
3. By producing a stereo picture, a closer three-dimensional relationship between the vascular lesion and the vessel circumference organization can be recognized.
4. Vascular lesions can be clearly visualized from inside the artery using a 3D-CT endoscopic image.
We were able to obtain a great deal of detailed information from 3D-CTA images with these modifications and we believe they enhance diagnostic accuracy of the technique.