An investigation of cerebral MR angioimaging

Magnetic resonance (MR) angioimaging was performed on patients with cerebrovascular diseases using three different techniques with a HITACHI G-10 (0.15 tesla) apparatus and a G-50 (0.5 tesla) apparatus. Direct (conventional) cerebral MR angioimaging employing the ''flow void'' phenomenon was useful for the evaluation of intracranial arterial diseases, such as intracranial aneurysms and arteriovenous malformations. For this purpose, a conventional spin-echo sequence with a long Tr (2000 - 3000 msec) and a short Te (30 - 50 msec) could delineate only the fast flowing vessels with a marked low-signal intensity, while other intracranial structures were shown as iso- or high-signal intensities. ECG-gated subtraction MR angioimaging was used only for the diagnosis of peripheral vessel diseases, because the intracranial vessels were not delineated clearly by this technique. A sequence subtraction technique with a rephased and a dephased sequence was used for the detection of diseases of cervical vessels and the intracranial venous system such as vascular obstructions. In conclusion, cerebral MR angioimaging is of diagnostic value for cervical and intracranial vascular diseases. (author)