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Purpose: In patients with ICA stenosis, increased peak systolic velocity is a marker of stenosis at risk of ischemic stroke. 4DFlow MRI is a reproducible technique to evaluate velocities in ICA stenosis, although it seems to underestimate velocities as compared with Doppler ultrasonography. The purpose of our study was to confirm that velocities were underestimated on a new set of data acquired with a clinical 4DFlow sequence, and to devise optimal acquisition parameters for ICA stenosis exploration based on a numerical simulation., Methods: After review board approval, 15 healthy controls and 12 patients presenting ICA stenosis were explored with Doppler ultrasonography and 4DFlow MRI. We created a 2-dimensional simulation of ICA stenosis and its corresponding 4DFlow acquisition, and compared its mean peak systolic velocity underestimation to real MRI and Doppler. We then simulated the acquisition for voxel size ranging from 0.5 to 1.25 mm and number of phases per cardiac cycle ranging from 10 to 25., Results: On acquired data, 4DFlow MR underestimated peak systolic velocities (mean difference between Doppler and 4DFlow: - 35 cm/s), especially high velocities. With spatial and temporal resolutions equivalent to MR acquisition, our simulation yielded similar underestimation (mean difference: - 31 cm/s, P = 0.30). Simulations showed that 0.7-mm resolution and 20 phases per cardiac cycle would be necessary to record peak systolic velocities up to 250 cm/s., Conclusion: Higher spatial resolution can provide accurate peak systolic velocities measurement with 4DFlow MRI, thus allowing better ICA stenosis assessment. Further studies are needed to validate the proposed parameters.

Paragangliomas arising in the suprasellar region are extremely rare. We report a case of suprasellar paraganglioma in a 47-year-old man who presented with amnesia and impaired visual acuity without any endocrine dysfunction. Magnetic resonance imaging (MRI) showed a large enhancing tumour in the suprasellar area. Following subtotal surgical excision, the diagnosis of paraganglioma was confirmed by pathology. In this case report we describe the MRI pattern of suprasellar paraganglioma and review the literature of this uncommon lesion.

Seizures, which may be the main expression of cerebral arteriovenous malformations (CAVM) can be difficult to control medically. Our goal was to use perfusion-weighted imaging (PWI) in correlation with clinical data to detect abnormal areas of the cerebrum related to a particular type of CAVM (proliferative angiopathy) and to study the pathophysiology. We use PWI, with a bolus injection of contrast medium, to investigate seven patients with proliferative angiopathy and fits producing language disturbance. Perfusion parameters were calculated using the first-pass moment theory. Five patients had perimalformative and/or contralateral abnormal areas with relative hyperperfusion (cerebral blood volume +20.7+/-16.2%, blood flow 92.5+/-68.8 ml/min/100 g). Areas of hypoperfusion and venous congestion were detected in two patients. One patient who underwent MRI after a severe focal deficit had no significant haemodynamic abnormality.

We report five cases of intracranial dural arteriovenous fistula (DAVF) with perimedullary venous drainage. All the patients presented with rapidly progressive myelopathy and three had autonomic disorders. The DAVF were on the tentorium cerebelli (two cases), sigmoid (one), superior petrosal (one), and cavernous sinus (one). Slow venous drainage was directed through dilated perimedullary cervical veins. The transverse sinus was occluded in two cases. MRI, performed in four cases, demonstrated high signal on T2-weighted spin-echo sequences in the medulla oblongata and upper cervical spinal cord consistent with oedema, which signal resolved after complete cure of the DAVF in three cases. Embolisation was performed in all cases. It was followed by clinical deterioration in two cases and in the dramatic improvement in the other three, with complete clinical cure in two. Extensive venous thrombosis may explain the deterioration observed in one case.

The overall haemorrhagic risk of a cerebral arteriovenous malformation (cAVM) is 2-4% per year. However, the individual risk of haemorrhage has never been determined. This study was undertaken to assess the haemorrhage risk of an individual cAVM. Neuroangiographic findings of 160 cAVM were analysed retrospectively, looking at 30 angiographic features. A statistical model was established by logistic regression to evaluate the risk of an individual cAVM. We statistically correlated 15 parameters with the haemorrhage risk. The statistical model includes five independent parameters. Four are unfavourable: exclusively deep drainage, venous stenoses, venous reflux and the radio of afferent to efferent systems; one is favourable: venous recruitment. This model quantifies the individual risk of haemorrhage. When this model is applied to the population studied, the error rate is 5%. This model can contribute to therapeutic strategy, and to a better understanding of the natural history of cAVM.

We report four cases of trigeminal neuroma. One of the patients had von Recklinghausen's neurofibromatosis with plexiform neurofibromas of the branches of the trigeminal nerve. MRI provided more information than CT as regards the spread of tumour: extension to the mandibular and maxillary division of the trigeminal nerve was well demonstrated on sagittal and coronal sections. This examination yielded an accurate census of the intraocular plexiform neurofibromas and allowed a correct preoperative diagnosis to be obtained. With Gd-DOTA, better definition of the outline of the tumours and of cystic components was obtained. However, CT was better for demonstration of bone erosions.

The authors report their experience based upon 56 cases of CT in cerebral thrombophlebitis. Direct signs of occlusion of the veins are infrequent and interest lies in the abnormalities due to brain edema or venous infarct. It is fundamental to recognize these infarcts as their evolution is favorable under treatment. Angiography is necessary to confirm the diagnosis of thrombophlebitis which can be only suspected on CT findings.

Extracranial vertebral arteriovenous fistulae of non traumatic origin are extremely rare. The authors report two cases of spontaneous vertebro-vertebral arteriovenous fistulae associated with fibromuscular dysplasia. They discuss the relation-ship between arteriovenous fistulae and fibro-muscular dysplasia, and the specific problems of treatment in these two cases.

The authors describe the epidemiology and the physiopathological aspects of ischemic strokes in patients with a history of oestroprogestogen use. They then study their main radiological correlates: arterial infarcts at CT scan and angiographic non-specific lesions which can be included in the extremely wide framework of arteritis and, much more rarely, venous thrombophlebitis.