[Asymptomatic cerebral hemorrhage detected by MRI].

Detection of previous cerebral infarction on CT films of patients with no history of stroke is a common occurrence. The incidence of silent cerebral infarction was reported to be about 10 to 11 percent, but very few reports concerning asymptomatic cerebral hemorrhage available. However, recent clinical application of MRI has resulted in the detection of old asymptomatic hemorrhage in patients with no history of known stroke-like episodes. The purpose of this study was to elucidate the incidence, the cause and the character of the asymptomatic cerebral hemorrhage among patients who had undergone MRI examinations. From September 1987 till June 1990, 2757 patients have undergone 3474 times of MR scan of the brain with 1.0 Tesla Siemens Magneton unit in our hospital. 17 patients showed no clinical signs or symptoms suggesting a stroke episode corresponding to the detected hemorrhagic lesion. Seventeen patients correspond to 0.6% of the patients who underwent MRI, 1.5% of the patients with cerebrovascular disease and 9.5% of the patients with intracerebral hemorrhage, which was rather higher than expected. Among the 17 patients, 12 were diagnosed as primary ICH and 5 as secondary ICH. Most of the primary asymptomatic hemorrhages were hypertensive ones and slit-like curvilinear lesions between the putamen and claustrum or external capsule. The secondary asymptomatic hemorrhages were due to AVM and angiomas in the frontal cortex, thalamus and pons.