Symptomatic Radionecrosis after AVM Stereotactic Radiosurgery. Study of 16 Consecutive Patients

SUMMARY

The purpose of our study was to analyze the outcome of symptomatic radionecrosis following stereotactic radiosurgery for brain arteriovenous malformations. Of 225 patients treated by linear accelerator radiosurgery for brain AVM, 16 (7,1%) presented post-radiosurgery symptomatic radionecrosis on a mean follow-up period of 50 months (range 1-123 months). Once diagnosed with radionecrosis, 14 of 16 patients were subjected to high dose corticotherapy consisting of escalating doses of dexamethasone for several weeks. The mean interval of occurrence of new symptoms was 11.6 months post-radiosurgery (range 6-20 months). The mean time of follow-up was 2.9 years post radiotherapy ranging from seven months to eight years. Of the 16 patients with symptomatic radionecrosis, 11 (68,75%) showed complete resolution of symptoms while five (31,25%) showed improvement but still presented a neurological deficit at the closing date of the study. At the closing date, 11 patients (68.75%) had angiographically completely obliterated arteriovenous malformations while another two patients had an obliteration of 95% to 98% and one patient had a 98% obliteration with development of a new contralateral AVM. In our series, symptomatic radionecrosis occurred in 7.1% of patients treated with stereotactic radiosurgery for brain AVM. These patients where subjected to a prompt, high dose corticosteroid treatment and most presented symptom resolution or improvement with a fair obliteration rate, offering protection from bleeding. Permanent neurologic deficits attributable to radionecrosis occurred in 2.2% of our patient population treated with stereotactic radiosurgery for brain AVM.

Comparison of intravenous and intra-arterial urokinase thrombolysis for acute ischaemic stroke

Intravenous fibrinolysis (IVF) with rt-PA (alteplase) provides significant benefits in acute ischaemic stroke when it is given within the first three hours following stroke onset. Intra-arterial fibrinolysis (IAF) with pro-urokinase in PROACT II study provides quite the same benefit in the first 6 hours. IVF and IAF have never been compared. To compare the efficacy and safety of IVF and IAF with urokinase given within the first 6 hours of acute ischaemic stroke. Patients fulfilling the selection criteria were randomly assigned to receive urokinase 900,000 units via intravenous or intra-arterial routes. This randomised monocentre study was done between December 1995 and August 1997. The primary outcome was defined as the number of patients with a modified Rankin score of 2 or less. Secondary outcomes included mortality, frequency of symptomatic intracranial haemorrhage (SIH), neurological and functional scores. Fourteen patients were given IVF and 13 IAF. The study was terminated by the National Health Authorities when 27 patients had been included because of the mortality rate. Seven patients (26%) died, 4 in the IV group (oedematous infarct in 3 and recurrence in 1), 3 in the IA group (SIH in 2, and oedematous infarct in 1). Patients given IVF were treated significantly earlier (4:16 h vs 5:24 h; p=.007). Although IA patients showed greater and earlier improvement there was no significant difference in primary and secondary outcomes. Because of premature termination, the trial was too small to provide any reliable and conclusive results. Intra-arterial fibrinolysis began significantly later than IV fibrinolysis but it gave non-significantly better results in this prematurely terminated study.

Mélanome primitif intrarachidien

Intra spinal primary melanoma is a rare entity. We report a new case, atypical in relation to its primary radicular location, and to its early metastatic intradural and extra-medullary location, six months later. MRI is the more valuable examination, showing a spontaneously hyper-intense lesion on T1-weighted MR images, intense enhancement after gadolinium administration, and decreased signal on T2-weighted MR images, thus suggesting a diagnosis of melanocytic or hemorrhagic lesion. Signal abnormalities are not specific and definitive diagnosis is established after histological analysis.

Persistent carotid-vertebrobasilar anastomoses

The persistent carotid-vertebrobasilar anastomoses (PCVBA) can be explained by an interruption of the vertebrobasilar system (VBS) embryogenesis. We present two very rare cases of persistent anastomoses: a hypoglossal artery and a type I proatlantal artery, insisting on the angiographic criteria allowing differentiation. After a brief review of the embryogenesis of the VBS, we describe the different types of persistent anastomoses (hypoglossal, type I and II proatlantal, trigeminal and otic arteries). We will insist on the potential risks, not well-known, but typical of each anastomosis. PCVBA usually are incidental findings but imaging follow-up may be required since aneurysms may develop.

Contrast-enhanced transcranial Doppler sonography in the follow-up of intracranial aneurysms after endovascular treatment

Two pilot studies on a small number of patients demonstrated the feasibility of transcranial Doppler ultrasound evaluation in the follow-up of intracranial aneurysms treated with detachable coils. This prospective study aimed to assess the sensitivity of contrast-enhanced transcranial echo-Doppler in detecting partial aneurysmal occlusion following endovascular treatment. Transcranial Doppler sonography (TCD) with contrast administration and magnetic resonance angiography (MRA) or angiography were carried out after endovascular treatment in 92 patients for 98 aneurysms of the anterior circulation. In 18% of cases, the quality of ultrasound exploration was deemed unsatisfactory for evaluation of the aneurysmal site. Results were concordant in 63% of patients (49/78). When occlusion appeared satisfactory at angiography or MRA, the result was concordant with TCD in 68% of cases (44/77). When a residual aneurysm was detected, TCD sensitivity was 38% (8/18). An analysis of subgroups failed to disclose anatomic or morphological aneurysm features in which transcranial echo-Doppler is sufficiently sensitive and specific to detect possible residual aneurysm or recanalisation. In our experience, even after contrast administration TCD is not sufficiently sensitive or specific in the detection of residual aneurysm to replace angiography or MRA.

Contribution of dynamic contrast MR imaging to the differentiation between dural metastasis and meningioma

PURPOSE

To determine the perfusion-sensitive characteristics of cerebral dural metastases and compare them with the data on meningiomas.

METHODS

Twenty-two patients presenting with dural tumor underwent conventional and dynamic susceptibility-contrast MR imaging: breast carcinoma metastases, two patients; colorectal carcinoma metastasis, one patient; lung carcinoma metastasis, one patient; Merkel carcinoma metastasis, one patient; lymphoma, one patient; meningiomas, 16 patients. The imaging characteristics were analyzed using conventional MR imaging. The cerebral blood volume (CBV) maps were obtained for each patient and the relative CBV (rCBV) in different areas was calculated using the ratio between the CBV in the pathological area (CBVp) and in the contralateral white matter (CBVn).

RESULTS

The differentiation between a meningioma and a dural metastasis can be difficult using conventional MR imaging. The rCBVs of lung carcinoma metastasis (1 case: 1.26), lymphoma (1 case: 1.29), breast carcinoma metastasis (2 cases: 1.50,1.56) and rectal carcinoma metastasis (1 case: 3.34) were significantly lower than that of meningiomas (16 cases: mean rCBV = 8.97+/-4.34, range 4-18). Merkel carcinoma metastasis (1 case: 7.56) showed an elevated rCBV, not different from that of meningiomas.

CONCLUSION

Dural metastases are sometimes indistinguishable from meningiomas using conventional MR imaging. rCBV mapping can provide additional information by demonstrating a low rCBV which may suggest the diagnosis of metastasis.

[Imaging of non-traumatic intracerebral hematoma]

Intracerebral hematoma is mainly due to the spontaneous rupture of small vessels damaged by chronic hypertension or amyloid angiopathy. In some cases, intracerebral hemorrhage may be associated with a vascular malformation, a tumor, venous thrombosis or hemorrhagic transformation of a cerebral infarct. The objective of brain imaging is to identify the hematoma according to its different stages and to find a potential underlying cause because of the risk of recurrence and the possibilities of treatment. In emergency, a diagnosis of hematoma may be obtained by CT scan or MRI but the etiologic work-up requires early MRI. According to the patient's age, the medical history and the location of the hematoma, it may be necessary to perform conventional angiography in order to exclude an intracranial vascular malformation. The aim of this review is to detail the different aspects of intracerebral hemorrhages and to discuss the main causes that can be found at brain imaging.

Risk of stroke and recurrent dissection after a cervical artery dissection: A multicenter study

OBJECTIVE

To assess the risk of stroke, TIA, or dissection recurrence after a first event of cervical artery dissection (CAD).

METHODS

The authors undertook a historical cohort study of consecutive patients with a first event of CAD who were admitted in 24 departments of neurology within a period of at least 1 year. Patients were retrospectively selected from a stroke data bank or from the local administrative data bank using the 10th revision of the International Statistical Classification of Diseases. A neurologist and a radiologist reviewed all charts to validate diagnosis and collect data. In 2002, patients were interviewed by phone or during a visit by the local investigators.

RESULTS

Four hundred fifty-nine patients (mean age 44.0 +/- 9.7 years) were included in the study. Among the 457 survivors, 25 (5.5%) could not be contacted in 2002 because they had moved. After a mean follow-up of 31 months, four (0.9%) patients presented a recurrent ischemic stroke attributable to either not yet completely recovered initial CAD (n = 2) or a recurrent CAD (n = 2). Eight (1.8%) patients had a TIA without CAD recurrence. Two TIA occurred at the acute stage of CAD. Of the six remaining TIA, only one was associated with chronic arterial stenosis. In addition, two patients had recurrent CAD without stroke, giving a total of four (0.9%) CAD recurrences.

CONCLUSIONS

Patients with a first event of CAD have a very low risk of ischemic events or dissection recurrences. Ischemic events seem rarely to be in relation with chronic arterial lesions.

[Thrombus of the left lateral sinus spreading to the internal jugular vein]

Cerebral venous thrombosis is an uncommon event which presents a wide spectrum of sometimes extraneurological signs different from the classical clinical presentation. We report the cases of two middle-aged women who developed thrombosis of the left lateral sinus spread-ing to the internal jugular vein from the sigmoid sinus. The time course of the symptoms suggested that intracranial thrombosis occurred first. No infectious or neoplastic local disease could be found but both women were taking oral contraceptives. Medical treatment led to good reperfusion of the intracranial sinuses but occlusion of the jugular vein persisted despite prolonged oral anticoagulants. Long-term outcome was favorable with residual benign epilepsy in one patient, and occurrence of an arteriovenous fistula in the other.

Selective endovascular treatment of intracranial aneurysms using micrus microcoils: preliminary results in a series of 78 patients

PURPOSE

To determine the safety and reliability of a new platinum microcoil (Micrus), in the treatment of intracranial aneurysms.

PATIENTS AND METHODS

Seventy-eight patients (28 male and 50 female patients; age range, 28-83 years; mean age, 44 years) with 80 intracranial aneurysms were treated in 10 centers in Belgium and France. All aneurysms were smaller than 15 mm. Nine aneurysms (11%) were located in the posterior circulation and 71 (89%) in the anterior. Fifty aneurysms (63%) were ruptured and 30 (37%) unruptured. Micrus microcoil is a new platinum coil. It is electrically detached with a time of detachment close to 5 seconds.

RESULTS

The degree of occlusion of the aneurysm was classified as total in 49 aneurysms (61%), subtotal in 28 cases (35%) and incomplete in 3 cases (4%). Technical complications were encountered in 10 patients (13%) including parent artery occlusion and thromboembolism (4 cases), coil migration (2 cases) and non-detachment of the coil (2 cases). The immediate morbidity rate was 1.3% and mortality rate 1.3%.

CONCLUSION

Micrus microcoils are effective and safe in the selective treatment of ruptured and unruptured intracranial aneurysms. Spherical microcoils are helpful to create a good basket in the aneurysmal sac at the beginning of treatment.