Background and Purpose A large percentage of patients with a cerebral arteriovenous malformation (AVM) show focal neurological signs or have a history of intracranial hemorrhage. The present study used transcranial Doppler sonography to assess the clinical significance of hemodynamic disturbances in the intracranial arteries of patients with an AVM.Methods Eighteen patients with untreated AVMs were examined clinically, angiographically, and with transcranial Doppler sonography (blood flow velocity measurement and vasomotor reactivity in all main intracranial arteries).Results A pathological increase in blood flow velocity (57.6%) and a decrease in vasomotor reactivity (72.7%) were frequently found in AVM feeding arteries. Vasomotor reactivity was also reduced in several nonfeeding arteries both ipsilateral (53.3%) and contralateral (30.8%) to the AVM. AVM size was a poor predictor of pathological transcranial Doppler results. Vasomotor reactivity of arteries ipsilateral to an AVM in patients with a history of hemorrhage was significantly higher (2.10±1.66% per mm Hg; mean±SD) than in

ABSTRACT. The ''spot sign '', described in 2007, has shown that a focal area of contrast extravasation within an intracerebral haematoma (ICH) can be correlated with haematoma expansion. Here we describe a case where time-resolved dynamic CT angiography (dCTA) shows the appearance of the ''spot sign'' only in later images. This shows the importance of timing of static CT angiogram that, if performed too early, might result in a false negative diagnosis. Haemorrhage in patients with intracranial arteriovenous malformation (AVM) usually occurs from the AVM itself or from an associated arterial aneurysm. We report a case of intracerebral haemorrhage arising from a remote varix related to the venous outflow of an ipsilateral frontal AVM. Case reportA 63-year-old male was admitted following a sudden onset of headache associated with neck stiffness and visual disturbances. There was no history of loss of consciousness or focal neurological deficit. On examination, the patient was photophobic and had nuchal rigidity. A visual field test showed a right homonymous hemianopsia but there were no other focal neurological signs.A non-enhanced CT of the brain ( Figure 1a) showed a large left temporal lobe intracerebral haemorrhage with secondary intraventricular and subarachnoid haemorrhage. There was also a calcified lesion in the left frontal lobe (Figure 1b), consistent with calcification within an AVM. A CT angiogram confirmed the presence of a left frontal AVM. An enhancing vascular structure adjacent to the left temporal lobe haematoma (Figure 1c) was demonstrated, representing either a flow aneurysm or a varix. MRI brain (Figure 1d) showed a left temporal intracerebral haematoma with an adjacent spherical area of flow void (Figure 1e), consistent with an aneurysm or varix. An AVM was noted in the left middle frontal gyrus (Figure 1d), distal from the area of haemorrhage. MR angiography (Figure 1f) showed enlarged arterial feeders arising from the left anterior and middle cerebral arteries.The conventional cerebral angiogram (Figure 2) confirmed the presence of a left frontal AVM (SpetzlerMartin grade 1-0-0) that was mainly supplied by branches of the left internal carotid artery. No arterial flow aneurysm was noted. The AVM had a peculiar way of draining. A primary single large collecting vein was divided into several smaller veins, majority of which were draining into the superior sagittal sinus via communication with superficial cortical veins. There was a single vein with a posteroinferior course. During late venous phase, two varices were seen on this vein (Figure 2c, f). Various degrees of stenoses were seen in the peripheral draining veins. The varix, adjacent to the area of haemorrhage, showed impaired outflow because of stenosed segments ( Figure 2f) and was probably the most vulnerable part of this AVM with regard to haemorrhage.During embolisation, the major right prefrontal middle cerebral artery feeder was initially catheterised and the tip of the microcatheter was placed intranidally within the AVM (Figur...