"Nidus sparing sign" on computerized tomography in intracerebral haemorrhage due to a rupture of arteriovenous malformation

Lobar intracerebral hemorrhage. A clinical, radiographic, and pathological study of 29 consecutive operated cases with negative angiography

The authors operated consecutively on 50 patients with lobar intracerebral hemorrhage during a prospectively designed study period from January, 1986, to March, 1990. They investigated the correlations between the underlying causes and the clinicoradiographic features in 29 patients who showed no angiographic vascular abnormalities, in order to elucidate the operative indication for such cases. Patients with ruptured saccular aneurysm or trauma were not included in this study. There were 15 males and 14 females, ranging in age from 7 to 76 years (mean 52.4 years). Histological diagnoses of the surgical specimens were as follows: vascular malformation in nine cases (arteriovenous malformation (AVM) in six and cavernous malformation in three), microaneurysm in 11, cerebral amyloid angiopathy in six, and brain tumor in two; in the remaining case the cause was not verified histologically. The underlying cause was determined in 96.5% of cases. The mean patient age was lowest in the cavernous malformation group (27.0 years), followed by the AVM (45.8 years), microaneurysm (59.8 years), and cerebral amyloid angiopathy (70.0 years) groups. Four patients with vascular malformation (three AVM's and one cavernous malformation) had previous episodes of bleeding at the same site, whereas none of those with microaneurysms or cerebral amyloid angiopathy had such episodes. On computerized tomography (CT) scans, the round to oval hematoma was related to the presence of an AVM or cavernous malformation in contrast to microaneurysms and cerebral amyloid angiopathy. Upon infusion of contrast material, variable enhancement was seen in five (two AVM's and three cavernous malformations) of the nine vascular malformations while no enhancement was noted in any patient with microaneurysm or cerebral amyloid angiopathy at the acute stage. Subarachnoid extension of the hematoma was associated with cerebral amyloid angiopathy significantly more frequently than with AVM's (p less than 0.05) and microaneurysms (p less than 0.01). The results suggest that clinicoradiographic pictures in cases with negative angiography are quite different among the three major pathological categories; namely, vascular malformation (AVM and cavernous malformation), microaneurysm, and cerebral amyloid angiopathy. It is suggested that the underlying etiology of a given lobar intracerebral hemorrhage with negative angiography may be predicted by a combination of patient age, history of previous bleeding at the same site, hematoma shape, and subarachnoid extension of the hematoma on CT scans. Based upon these findings, the authors discuss operative indications for such cases.