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We reviewed 11 cases of intramedullary cavernous haemangiomas (IMCH) studied by MRI, to assess its diagnostic value in these lesions. Follow-up MRI was obtained in five patients 7 days-2 years following the initial study. In one case a postoperative examination was obtained. The diagnosis was pathologically proven in ten cases, and supported in the last by a family and personal history of cavernous haemangiomas. A reticulate appearance with areas of mixed signal intensity in both T1- and T2-weighted images was the most common finding. Homogeneous high, low or intermediate signal intensity was each found in one case. Two small lesions gave low signal. A rim of low signal was less common than in cerebral cavernous haemangiomas. In one case, the brain showed more than 20 lesions with the MRI appearances of cavernous haemangiomas. In two of five patients, serial preoperative MRI showed progressive disappearance of high-signal areas on both T1- and T2-weighted images. To find a haemorrhagic intramedullary lesion on MRI is not rare. Although the appearances are not pathognomonic, an IMCH can be suggested. We suggest that the following characteristics may help: (1) a personal and/or family history of cavernous haemangiomas; (2) typical MRI appearances of mixed acute, subacute and chronic haemorrhage; (3) a tendency for signal intensity to decrease on follow-up; (4) normal spinal angiography; and (5) associated brain lesions.

A total of 162 patients with suspected acoustic neuromas underwent MR imaging at 1.5 T. All patients were injected with Gd DTPA or DOTA. In 72 patients, uni- or bilateral acoustic neuromas were detected. 18 cases were equivocal: In 9 cases, contrast enhancement was due to other tumors (5 meningiomas, 2 metastases, 1 hemangioma). In 1 case, misinterpretation resulted from partial volume effects with the petrous bone marrow. In one patient, previously operated on, increased signal was due to postoperative fat graft. Four hypersignals were due to intracanalicular venous or meningeal enhancement. Three cases are still equivocal. Most of the diagnostic problems may be obviated by precontrast MR imaging, multidimensional 3-mm sections, and fast imaging.

Hemangiomas are tumors. Hemangiomas near the geniculate ganglion or in the internal acoustic meatus are well known but rare. We present two cases of hemangiomas located at the porus acusticus, an even more rare site. MRI showed a millimeter-sized tumor, located in the porus acusticus, developing perpendicular to the axis of the acoustico-facial nerves, surrounding them. They were hyperintense on T1-weighted images, strongly hyperintense on T2-weighted images with a characteristic progressive and marked enhancement after injection of gadolinium DTPA. Similar signal abnormalities were present in the adjacent temporal bone, and CT scan demonstrated a honeycomb appearance with intratumoral bony spicules. These imaging criteria allows differentiation between hemangioma and neurinoma. We hypothesize that this location is related to the presence of a rich vascular plexus of the dura mater in this area.

The central canal of the spinal cord is present at birth and becomes progressively obliterated. Cadaver studies have shown that it may persiste partially or completely. To our knowledge, this entity has not been described on MRI. We reviewed 794 MRI studies of the spinal cord, and found 12 patients (aged 14 to 65 years) who had an intramedullary cavity. The cavity was at the junction of the ventral 1/3 and dorsal 2/3 of the spinal cord, except at the level of the lumbar enlargement, where it was central. It was filiform in most cases, although sometimes fusiform (3 to 4 mm in diameter), and had regular contours. The cavity were thoracic in 69 % of cases. The clinical features were totally unrelated to the image, and there were no anatomical factors (Chiari malformation, dysraphism) predisposing to syringomyelia. The images were perfectly compatible with a persistent central canal, which we interpret as a variant of normal anatomy. Therefore it is important to regard these findings as normal, to avoid unnecessary treatment and follow-up.

An 8-year-old child was examined because of conductive hearing loss with a retrotympanic mass on otoscopy. CT and MR angiography showed a large inferior tympanic artery traversing the hypotympanum and joining a thin, irregular internal carotid artery with a normal middle meningeal artery. These investigations, coupled with knowledge of the embryological development allowed a diagnosis of a complex vascular anomaly in the middle ear and avoided potential surgical complications.

We present a case of osteoid osteoma of the petrous bone presenting with progressive sensorineural hearing loss. CT showed a dense homogeneous mass at the promontory surrounded by a thin bony border. On MRI this lesion gave intermediate signal intensity on T1- and T2-weighted spin-echo images and enhanced intensely with gadolinium. Surgical removal and pathological study proved the diagnosis.

Two cases of central nervous system Behcet's disease, studied by gadolinium-enhanced MRI, are presented. In one patient, whose clinical picture was dominated by a brain stem syndrome, the gadolinium enhancement resolved with clinical improvement, although the hyperintense areas in the mesencephalon on T2-weighted images persisted. In the second, who had a pseudobulbar palsy and a mild right hemiparesis, there were many abnormal areas, but an enhancing focus in the posterior limb of the left internal capsule was probably the lesion responsible for the hemiparesis.

Confusion developed in a 44-year-old man, who had diarrhoea and weight loss for three months. Jejunal biopsy showed infiltration by PAS-positive macrophages, indicating Whipple's disease. Cranial MRI disclosed multiple lesions mainly in the white matter and grey-white matter junction better demonstrated after gadolinium injection.

The successful treatment of a congenital vertebral fistula with the balloon catheter occlusion technique is reported. A new approach is presented (the occipital approach), based upon the pathological enlargement of the second intervertebral space anastomosis between occipital and vertebral arteries.

The normal development of the hyoidostapedial system and its branches and anastomosis are outlined. The intrapetrous facial nerve receives its arterial suplly from the network. The arterial arch of the facial nerve is seen more frequently in angiograms of infants than in those of adults. The fact that the same vessel supplies the VIIth and the Vth nerves suggests that an ischemic mechanism may frequently be involved in Bell's palsy. The facial nerve from the point of view of its arterial supply must be considered as a nerve of the middle fossa and represent the major risk of embolization in the propinal middle meningeal artery.

Many arguments lead us to think that a possible etiologic factor in idiopathic Bell's palsy is the ischemia of the facial nerve and that angiography could help in diagnosis: (1) the rapid progress of the paralysis; (2) the correlation between Bell's palsy occurring after embolization of the internal maxillary artery, the middle meningeal artery, the occipital or posterior auricular artery, and their participation in the blood supply of the facial nerve; (3) the already known ischemic third nerve paralysis reported in diabetes and extending further to the facial nerve. Even if it is technically impossible to study Bell's palsy by angiography, it is interesting to understand and consider some complications of embolization and perhaps to envisage a new kind of treatment.

Many arguments lead us to think that a possible etiologic factor in idiopathic Bell's palsy is the ischemia of the facial nerve and that angiography could help in diagnosis: (1) the rapid progress of the paralysis; (2) the correlation between Bell's palsy occurring after embolization of the internal maxillary artery, the middle meningeal artery, the occipital or posterior auricular artery, and their participation in the blood supply of the facial nerve; (3) the already known ischemic third nerve paralysis reported in diabetes and extending further to the facial nerve. Even if it is technically impossible to study Bell's palsy by angiography, it is interesting to understand and consider some complications of embolization and perhaps to envisage a new kind of treatment.

The middle meningeal artery can sometimes supply the complete vascularisation of the posterior fossa, i.e., the dura mater of the cerebellar fossa and the tentorium cerebelli. The authors present an anatomic and radiologic correlative study based upon an unusual case where the middle meningeal artery arose from the ascending pharyngeal artery and vascularised the entire posterior cerebellar fossa.

Since Parkinson's original description, the C5 collaterals are always presented as originating from a common trunk (meningo-hypophyseal). This is the least frequent anatomical variation. In fact, the posterior (C5) group of collaterals corresponds to the remnant of two transient embryonic vessels (primitive maxillary and trigeminal arteries), branches of which will give rise to the two main groups of collaterals originating from this area: medially, the inferior hypophyseal and the medial clival arteries; laterally, the basal tentorial and lateral clival arteries, which are constantly anastomosed with the ascending pharyngeal artery. Only in some cases (10%) do these two groups arise in common from the C5 carotid siphon. Apart from these branches the so-called Bernasconi's artery may originate from eight different pedicles, the C5 siphon representing only one of them.

The normal development of the hyoidostapedial system and its branches and anastomosis are outlined. The intrapetrous facial nerve receives its arterial suplly from the network. The arterial arch of the facial nerve is seen more frequently in angiograms of infants than in those of adults. The fact that the same vessel supplies the VIIth and the Vth nerves suggests that an ischemic mechanism may frequently be involved in Bell's palsy. The facial nerve from the point of view of its arterial supply must be considered as a nerve of the middle fossa and represent the major risk of embolization in the propinal middle meningeal artery.

The middle meningeal artery can sometimes supply the complete vascularisation of the posterior fossa, i.e., the dura mater of the cerebellar fossa and the tentorium cerebelli. The authors present an anatomic and radiologic correlative study based upon an unusual case where the middle meningeal artery arose from the ascending pharyngeal artery and vascularised the entire posterior cerebellar fossa.

Since Parkinson's original description, the C5 collaterals are always presented as originating from a common trunk (meningo-hypophyseal). This is the least frequent anatomical variation. In fact, the posterior (C5) group of collaterals corresponds to the remnant of two transient embryonic vessels (primitive maxillary and trigeminal arteries), branches of which will give rise to the two main groups of collaterals originating from this area: medially, the inferior hypophyseal and the medial clival arteries; laterally, the basal tentorial and lateral clival arteries, which are constantly anastomosed with the ascending pharyngeal artery. Only in some cases (10%) do these two groups arise in common from the C5 carotid siphon. Apart from these branches the so-called Bernasconi's artery may originate from eight different pedicles, the C5 siphon representing only one of them.