T2*-weighted gradient-echo (GE) magnetic resonance images frequently demonstrate small hypointense lesions in patients with systemic hypertension and spontaneous hematomas. These lesions have been suspected to represent subclinical microhemorrhages. We examined the incidence of these lesions in neurologically healthy adults, and the factors associated with them. Axial T2*-weighted GE images (TR = 1,000 ms, TE = 30 ms, flip angle = 20 degrees) were obtained in addition to conventional T1- and T2-weighted spin echo images in 450 neurologically healthy Japanese adults (289 men and 161 women; age 52.9 +/- 7.7 years, range 24-84). The overall incidence of small hypointense lesions was 3.1% (14/450), and these lesions were closely related to systemic hypertension (P < 0.0001) and heavy cigarette smoking (>20 cigarettes per day; P=0.003). Although the incidence of hypointense lesions was lower in neurologically healthy adults than in the reported incidence in patients with a hemorrhagic history, the presence of these lesions was related to the risk factors for primary intracerebral hemorrhage even in the neurologically healthy adults.

The authors have studied the indications and limitations for computerized tomography (CT)-guided stereotaxic surgery (CTGS Surgery) of hypertensive intracerebral haematomas (ICH), based on the analysis of 158 patients in our institutions. Of 158 patients, 120 had putaminal haemorrhage, 21 thalamic, 14 subcortical and 3 in other locations. The patients ranged in age from 37 to 82 years (average 60). Haematoma volume ranged from 8 to 140 ml (average 43). Eleven patients in the series worsened postoperatively because of rebleeding in 6 cases, cerebral infarction in 2, and unknown causes in the remaining 3 cases. Seven of the 11 patients pre-operatively had untreated hypertension and 3 had mild liver dysfunction without major haemorrhagic tendency. Most postoperative complications were seen in older patients and in those with severe neurological deficit or chronic disease. All these cases ended in poor outcome. From our study, we propose three indications for CTGS Surgery: absolute, aggressive and passive indications. The absolute indication is applied to those who would have been operated on by conventional open surgery. The aggressive indication is for those with mild neurological deficit so that early rehabilitation can be started to regain higher cerebral function. The passive indication is for elderly patients and those with severe neurological deficit or chronic disease. This indication must be decided carefully because poor outcome is likely.

Changes in cerebral blood flow (CBF) after CT guided stereotactic aspiration of putaminal haematoma were investigated in 13 patients with Xe-133 inhalation and single photon emission computed tomography. The interval from onset to operation ranged from 13 to 82 days (mean 30 days). The mean estimated haematoma volume ranged from 20 to 50 ml (mean 31.9 ml). The percentage of haematoma aspirated ranged from 75 to 98% (mean 86.8%). Postoperative CBF in two thirds of the patients was improved even though all cases were operated on in the subacute stage. Both the mean hemispheric and regional CBF in the anterior territory of the middle cerebral artery and in the region of the thalamus and basal ganglia in the affected hemisphere were increased postoperatively. Also in the nonaffected hemisphere, regional CBF in the region of the thalamus and basal ganglia was improved.

We report a 73-year-old woman with de novo arteriovenous malformations (AVMs) that developed in the ipsilateral parietal lobe after craniotomy and aneurysm clipping. While intracerebral AVMs are considered to be congenital lesions, there have been several reported cases of acquired AVM arising after ischemic or traumatic episodes. We summarize previously reported cases of such acquired ‘de novo’ AVMs with a discussion of some pathophysiological responses or factors suggested to promote their development.