[On the miliary intracranial aneurysm --its significance in subarachnoid hemorrhage (author's transl)].

Clinical use of four-vessels angiography increased the frequency of detection of intracranial aneurysm in patients who had episode of subarachnoid hemorrhage. However, some cases of subarachnoid hemorrhage did not show intracranial and intraspinal source of bleeding angiographically. Bjökesten and Troupp pointed out that some cases who were negative in angiography may have a very small intracranial aneurysm. Hassler described the minute aneurysm sized less than 2 mm in diameter from finding autpsy of the cases of subarachnoid hemorrhage and he emphasized that source of subarachnoid hemorrhage in tow cases were ruptured minute aneurysm. From the authors' experiences of ten very small intracranial aneurysms, the authors' advocated a name of miliary intracranial aneurysm in clinical practice. The author's criteria of the miliary intracranial aneurysm are as follows: (1) the miliary aneurysm grew from the wall of main trunk of intracranial artery, (2) the maximum diameter and height of protrusion of the miliary intracranial aneurysm are less than the diameter of parent artery. Ten miliary intracranial aneurysms are divided into two groups, one is the miliary intracranial aneurysm which is source of subarachnoid hemorrhage and the other is an accessory aneurysm bedise the another ruptured main aneurysm. These two groups were 5 aneurysms respectively. The majority of the accessory miliary intracranial aneurysms were observed in middle cerebral artery but the ruptured miliary intracranial aneurysms were observed in internal carotid artery, anterior communicating artery and middle cerebral artery. When the clinical symptom occurred at the time of rupture of miliary intracranial aneurysm compare with the one by rupture of usual major intracranial aneurysm, clinical symptom due to meningeal irritation was not different with each other but disturbance of consciousness and other neurological symptom were slight in miliary intracranial aneurysm cases. Angiographic diagnosis of miliary intracranial aneurysm is difficult, because differentiation of the miliary intracranial aneurysm from the loop or angulation of small artery is difficult in routine angiogram. In the case who showed questionable shadow as miliary intracranial aneurysm, the repeated angiography under modified direction of X-ray and modified head position of patient is required. The magnification cerebral angiography of three fold is also useful in diagnosis of miliary intracranial aneurysm. The intracranial treatment of miliary intracranial aneurysms were done by coating except one case whose aneurysm was clipped.