多方向脳血管CTにおける正常脳血管の走行形態に関する基礎的研究—Postmortem cerebral computed angiotomographyによる検討，Part II, modified coronal, Towneおよびsemisagittal plane

MULTIPLANE POSTMORTEM CEREBRAL COMPUTED ANGIOTOMOGRAPHY:PART II, NORMAL ANATOMY OF CEREBRAL VESSELS ON THE MODIFIED CORONAL, TOWNE AND SEMISAGITTAL PLANES

　抄録　脳血管およびその病変をCT画像上に立体的に把握するためには，これらの走行形態を多方向からdirect scanを行うことが重要である。今回，かような基盤にたちaxial plane以外の方向（modified coro—nal, Towne （half-axial）　and semisagittal planes）から把えた正常脳血管像に関して，postrnortem cerebralcomputed angiotomographyによる検討を行った。Modified coronal planeは，　carotid fork,anteriorand middle cerebral arteriesおよびlenticulostriate arteriesの描出にすぐれ，臨床的にはこれらの鎖域の脳動脈瘤，脳血管閉塞症，モヤモヤ病等に対する診断的応用が期待される。Towne planeおよびsemi—sagittal planeは，それぞれvertebro-basilar arterial system，および正中，旁正中部血管構造の描出に適していると思われた。多方向脳血管CTは，脳血管およびその病変を，またその他の病巣と脳血管との関係を立体的に把握する上で有用であり，今後CT診断学の面で新しい情報をもたらすことが期待される。

In order to obtain a detailed knowledge of the cerebral vasculature on computed tomographic (CT) images, multiplane CT scannings on the axial, coronal, Towne and sagittal planes are required. Previous reports have concerned only the axial CT images of the cerebral vasculature, and no mention has been made about the vasculature on the coro-nal, Towne or sagittal images.

This paper concerns the normal anatomy of the cerebral vessels on the modified coronal, Towne (half-axial) and semisagittal CT planes using 9 fresh cadavers. They received postmortem injection of contrast agents and were scanned by GE-CT/T 8800 as mentioned in Part I. Scanning planes were the modified 50-60°coronal, Towne (40-45° off the can-thomeatal line), and the semisagittal (45° toward the sagittal plane).

The main vascular structures visualized on the modified coronal CT plane resembled the antero-posterior view of the carotid angiogram, and they were as follows : internal carotid arteries (supra-clinoid portion), posterior communicating arteries, anterior choroidal arteries, anterior cerebral arteries (horizontal and ascending portions, pericallosal and callosomarginal arteries and other cortical branches),middle cerebral arteries (horizontal, insular, oper-cular and terminal portions with identification of the angiographic Sylvian point), lenticulostriate arteries, posterior cerebral arteries, basal vein of Rosenthal (BVR), internal cerebral veins (ICV), subependymal veins which drain into BVR and ICV, choroid veins, vein of Galen, and venous sinuses.

As for the demonstration of the lenticulostriate arteries or the Moyamoya vessels in clinical cases, the modified coronal plane is preferred to the axial one.

On Towne plane, the vertebro-basilar arteries and the ascending portion of anterior cerebral artery were demonstrated as linear densities, which were demonstrated as spotty densities on the axial plane.

On the semisagittal plane, the median or para-median vasculatures of the main cerebral arteries and deep cerebral veins, were well demonstrated like a lateral view of carotid angiogram.

Biplane or multiplane cerebral computed angio-tomography will increase in clinical diagnostic value for understanding the anatomical relationship between the cerebral vessels and other intracranial lesions, and also will be applied to the screening of small vascular lesions themselves, e.g., asympto-matic aneurysms, vascular occlusions, arteriovenous malformations and Moyamoya diseases.