William Harper

Toronto Western Hospital, Toronto, Ontario, Canada

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Publications (2)4.52 Total impact

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    ABSTRACT: Despite recent studies of the natural history of cavernous malformations, there remains significant uncertainty concerning hemorrhage rates and the importance of lesion location. Controversy arises over varying definitions of "hemorrhage." What is ultimately important to the patient is the occurrence of a neurological event, which may or may not be associated with radiologically documented hemorrhage, as well as the chance of recovery after such an event. The purpose of this study was to determine the rates of occurrence and sequelae of neurological events in 173 patients referred to our vascular malformation clinic with cavernous malformations. All patient data were entered into a database. The mean age at presentation for the 173 patients was 37.5 years. The lesion location was deep (brainstem, cerebellar nuclei, thalamus, or basal ganglia) in 64 patients (37%) and superficial in 109 (63%). Thirty-one patients (18%) had multiple lesions. Disease presentation was due to seizures in 62 patients (36%), hemorrhage in 44 (25%), focal neurological deficit without documented hemorrhage in 35 (20%), headache alone in 11 (6%), and incidental findings in 21 patients (12%). The results obtained in the 110 patients eligible for follow-up review were used to derive information on the rates of hemorrhage and neurological events. An interval event (neurological deterioration) required both symptoms and signs. The total mean follow-up period was 46 months, the majority (65%) of which was prospective. There were 18 interval events in 427 patient-years of follow-up review, for an overall annual event rate of 4.2%. Location was the most important factor for predicting interval event occurrence, with significantly higher rates for deeply located (10.6%/year) compared with superficially located lesions (0%/year) (p = 0.0001). Of patients suffering a neurological event, only 37% had complete resolution of their deficits. This largely prospective study indicates that deep cavernous malformations carry a worse prognosis than superficial lesions with respect to annual rates of neurological deterioration. The alarming rate of adverse clinical events occurring in patients with deep lesions is punctuated by the fact that less than one-half of them recover fully during long-term follow-up review.
    Journal of Neurosurgery 09/1997; 87(2):190-7. DOI:10.3171/jns.1997.87.2.0190 · 3.74 Impact Factor
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    ABSTRACT: The purpose of this review was to determine whether a classification scheme for cavernomas based on the MR appearance is predictive of the natural history of the lesions with particular reference to the risk of haemorrhage. We reviewed the clinical and MR findings in 156 patients with intracranial cavernomas. The dominant or symptomatic cavernoma was graded into three groups according to the appearance of the blood products. The presence of haemorrhage, mass effect and oedema was evaluated. Sixty patients had serial MRs with a mean follow-up of 1.9 years. Subacute haemorrhage with mass effect and oedema was evident on the initial MR in 30 patients (19%). In seven patients follow-up MR showed haemorrhage with mass effect and oedema. Six of these bleeds were in the posterior fossa. The haemorrhages seen on follow-up MR occurred in all three morphological types. Regression was found on follow-up MR in five of the seven patients who initially showed a bleed. In 35% of patients, the dominant or symptomatic cavernoma changed on serial MR. Intracranial cavernomas are dynamic lesions with both active and regressive changes seen on follow-up MR. A classification system based on morphology was not found to be useful in predicting future bleeds. Bleeding rates, based on MRfollow-up, were 10.9% in the posterior fossa and 1.7% in the supratentorial compartment.
    Interventional Neuroradiology 06/1996; 2(2):127-35. · 0.78 Impact Factor