M.R.I. spectrum of intrinsic spinal cord lesions

We report our experience of 42 patients undergoing magnetic resonance imaging (MRI) studies demonstrating intrinsic lesions of the spinal cord, excluding those secondary to spondylosis, trauma or congenital malformations. Histological confirmation of the radiological diagnosis was obtained in 15 (36%). MRI is more sensitive than either myelography or CT. MRI identified a previously non-visualised lesion in 17 of 30 cases. In a further 13 cases, MRI contributed by identifying associated features such as cysts and haemorrhage which have aided in the diagnosis and management of the patients. The last 12 cases, which were patients with multiple sclerosis, had MRI as the only neuroradiological examination. These illustrate a range of appearances. The overlap of imaging appearances of the various pathologies implies that a useful diagnosis and differential can only be offered by considering the MRI appearances of a lesion, with its associated features, with the clinical presentation, and with other imaging modalities where appropriate.

MRI of lumbar and sacral plexus nerve sheath tumours

Seven patients with peripheral nerve sheath tumours affecting the lumbo-sacral plexus were examined with MR imaging utilizing a 1.5T magnet and spin echo pulse sequences. The majority of tumours were homogeneous in signal intensity and isointense with adjacent muscle on T1 weighted images and showed markedly increased signal intensity on T2 weighted images with central areas of relatively low signal intensity. An attempt to obtain a pathological correlation with the areas of low signal on T2 weighted images was unsuccessful. The use of Gadolinium DTPA in one patient resulted in irregular enhancement of both a neurogenic sarcoma and smaller neurofibromas. The multiplanar imaging capabilities, high soft tissue contrast, non-invasiveness, lack of ionizing radiation and the characteristic appearance of neural tumours makes MR ideal for imaging these lesions.

Case report: MRI diagnosis of congenital absence of the internal carotid artery

Congenital absence of the internal carotid artery is a rare anomaly that has previously required angiography for diagnosis. Magnetic resonance imaging (MRI) provides good visualization of major arterial structures, and in this case documented the absence of the left internal carotid artery.

The evaluation of thoracic paraspinal neurogenic tumours. The role of magnetic resonance imaging

Paraspinal neurogenic tumours may have associated intraspinal tumour extension. It is important that such extension be accurately defined preoperatively in order that an appropriate surgical approach may be planned. It has been suggested in the literature that MRI (where available) should replace myelography and post myelographic CT in the preoperative evaluation of these patients. The literature is reviewed and the potential role of MRI is illustrated in three cases.

Hepatic adenoma and focal nodular hyperplasia: a diagnostic dilemma

Focal Nodular Hyperplasia (FNH) and Hepatic Adenoma (HA) remain difficult diagnostic problems due to their variable imaging appearances. Five new cases are presented, illustrating this variability, and the current literature is reviewed. Ultrasonography is a sensitive modality for their detection but is otherwise non-specific. On computer tomography, the presence of a scar suggests FNH, whilst haemorrhage suggests HA. However these features are seen in only a small number of cases. Radionuclide (colloid) scanning aids considerably in FNH but a definitive role has not been found in HA. Angiography is helpful, providing anatomical information, sometimes diagnostic (septated blush in FNH, hypovascular areas in HA) and able to discern benign from malignant lesions. Where imaging is not definitively diagnostic, percutaneous biopsy is indicated if FNH is suspected and surgical biopsy if HA is felt likely.

Is that another Thornwaldt's cyst on M.R.I.?

20% of 200 M.R.I. head scans displayed increased signal in the midline posterior-superior nasopharynx in the position of the pharyngeal bursa. Though these likely represent a number of different entities, Thornwaldt's cysts may be more common than previously realised.

Cervical myelopathy due to calcification of the ligamentum flavum

An elderly Caucasian woman presented with a cervical myelopathy due to cervical spinal cord compression posteriorly by calcified ligamentum flavum and anteriorly by cervical osteophytic bars. Although recognized in the Japanese population, calcification of the ligamentum flavum as a cause of cervical myelopathy is very rare in Caucasians, with only one case previously reported.

Detection of basilar artery thrombosis by computed tomography

Thrombosis of the basilar artery is not uncommon and occurs in the elderly as well as in younger patients. The clinical diagnosis may be supported by the appearance on computed tomography enabling appropriate investigations and therapeutic measures to be taken which may lead to a favourable outcome. Four cases of basilar artery thrombosis are described in which the clinical diagnosis was assisted by computed tomography. The basilar artery, which is normally isodense in unenhanced studies, was seen as a hyperdense structure. Follow-up scans demonstrated a decrease in the density and size of the vessel consistent with resolution of a thrombus.

The morbidity of CT air meatography: a follow-up of 84 patients

At present CT air meatography is the examination of choice for all patients suspected of having a small acoustic neuroma not demonstrated by high resolution contrast enhanced computed tomography. Several publications have indicated that the examination is innocuous and can be carried out on an outpatient basis. An analysis of the side effects of this procedure in 84 patients suggests that it carries a significant morbidity and patients undergoing this examination should be admitted to hospital for at least 24 hours.

Chiasmal apoplexy due to intrachiasmatic vascular malformation rupture

Hemorrhage from an intrinsic vascular malformation of the optic chiasm (chiasmal apoplexy) is an uncommon cause of sudden visual loss with chiasmal visual field defects. This paper describes one case of sudden visual loss with an anterior chiasmal visual field defect due to rupture of an intrachiasmatic venous angioma and contrasts it with the clinical presentation of a case of hemorrhage from an intrachiasmatic arteriovenous malformation causing severe headache and a less apoplectic onset of visual symptoms. The variable clinical presentation and the accuracy of high resolution post-contrast cranial CT scan in the diagnosis of intrachiasmal hemorrhage is highlighted.

Asymptomatic cerebellar venous angioma

In contrast to the scarcity of recorded cases of radiologically studied venous angiomas, venous angiomas are the most common of the four basic types of congenital intracranial vascular malformations encountered incidentally at autopsy. Their clinical significance remains unclear. When symptomatic, they are associated mainly with hemorrhage or mechanical pressure on cranial nerves by anomalously enlarged veins, however, it is, as yet, impossible to predict what course an asymptomatic cerebellar venous angioma will take. The risks of surgery appear to exceed those of the natural history of the disorder. The following two cases of asymptomatic cerebellar venous angioma are recorded because of the rarity of the condition's diagnosis and the possibility of controversy in its conservative management.

Glomus intravagale tumour: aspects of management

Glomus intravagale tumours are relatively rare tumours. A case is described and some aspects of its management are discussed with emphasis on the pre-operative investigation and diagnosis of this condition. Selective embolization of the lesion before operation is an important adjunct in treatment to reduce the vascularity of the tumour during operation. Intra-operative cardiac arrest due to traction of the vagus nerve was encountered. The methods to avoid this complication are discussed.

Assessment by computed tomography of the response of pituitary macroadenomas to bromocriptine

Eleven patients with large pituitary tumours and with extrasellar extension were studied prospectively to assess the response of these tumours to bromocriptine. Five out of the six patients with high serum prolactin due to prolactinomas showed rapid and dramatic reduction in tumour size when treated with bromocriptine. In contrast, none of the five patients with non-functioning tumours showed any change in tumour size on computed tomography.

Management of extra-sellar pituitary tumours with bromocriptine: comparison of prolactin secreting and non-functioning tumours using half-field visual evoked potentials and computerised tomography

To determine whether prolactin secreting and non-functioning pituitary tumours respond differently in terms of shrinkage to bromocriptine, we prospectively studied ten consecutive patients (five with prolactinomas and five with non-functioning tumours) complicated by extra-sellar extensions. No patient had received prior radiotherapy or bromocriptine and the mean dose and duration of bromocriptine treatment were identical in the two groups of patients. Objective evidence of tumour shrinkage was provided by serial half-field visual evoked potentials (VEPs) and computerised tomography (CT). All five prolactinomas were shown to shrink as assessed by improvement in VEP and four of the five as assessed by CT. In contrast, only one of the five patients with non-functioning tumours showed any improvement in VEP or CT. Macroprolactinomas frequently shrink rapidly when treated with bromocriptine, whereas non-functioning tumours seldom show such a dramatic response.

Arteriovenous malformations of the mandible

Arteriovenous malformations of the mandible may present with pulsatile tinnitus, pain, a bruit, loosening of teeth, or intraoral or facial deformation or discoloration. In the absence of these classic symptoms and signs, the unwary surgeon might attempt a limited excision, leading to massive intraoperative hemorrhage. Management includes external carotid as well as selective branch arteriography and preoperative arterial embolization with polyvinyl alcohol sponges and absorbable gelatin. Vessel ligation, mandibular resection, lesion excision, mandibular autografting, and intermaxillary fixation complete surgical treatment.

High resolution CT air cisternography in the diagnosis of small acoustic neuromas

High resolution CT air cisternography was used to examine 38 patients with clinical findings and audiovestibular function studies consistent with a retrocochlear lesion. Four strictly intracanalicular lesions and 10 acoustic neuromas extending medially into the cerebellopontine angle (CPA) cistern by no more than 1 cm were detected and verified at surgery. There was one false-positive diagnosis produced by a tortuous inferior cerebellar artery branch. The contrast-enhanced axial scan was positive in only two patients. Both had extension of the tumor into the CPA by 1 cm. In these two cases the axial intravenous (IV) contrast-enhanced scan provided more information than the air CT. A patient with suspected acoustic neuroma is best examined initially with an IV contrast-enhanced axial scan followed by CT air cisternography where the contrast study is negative.

Intracerebral hemorrhage and vasculitis related to ephedrine abuse

Intracerebral hemorrhage occurred in a 20-year-old man following self-administration of ephedrine. Changes seen on cerebral angiography were typical of vasculitis, and immune complex deposition was found in a skin biopsy. This combination has not previously been reported with ephedrine abuse although it is well known with amphetamine abuse.