MR Imaging in Multiple Sclerosis: The Accuracy of 3D Double Inversion Recovery at 3 Tesla and the Potential for Single Sequence Imaging

To compare the accuracy of a three dimensional, T2-weighted double inversion recovery (DIR) sequence with two dimensional fluid attenuated inversion recovery (FLAIR) and dual echo T2 (DE T2) sequences at 3 Tesla in the detection of intracranial demyelinating lesions in patients with known or suspected multiple sclerosis (MS), and to consider the appropriateness of a stand-alone DIR sequence in MS imaging. The studies of 98 patients who underwent imaging with DE T2, FLAIR and DIR sequences for known or suspected multiple sclerosis were retrospectively reviewed. In 42 cases, a diagnosis of MS had been clinically suspected. In the remaining 56 cases, a diagnosis of MS had been previously established. All patients were imaged on a 3T MRI unit. Coronal and sagittal FLAIR, axial DE T2, and three dimensional T2-weighted DIR sequences were utilised. Of the 42 patients with suspected multiple sclerosis, 11 demonstrated lesions characteristic of the disease. Demyelinating plaques were seen in all of the 56 patients with known MS. In all cases, all lesions seen on DE T2-or FLAIR sequences were visible and more conspicuous on the DIR sequence. In 22 of the 67 patients (33%) with demyelinating lesions, the DIR sequence showed additional lesions not visible on any of the other sequences. Additional detected lesions predominantly involved grey matter. At 3 Tesla, a T2 weighted, three dimensional DIR sequence is as accurate at detecting the presence of intracranial demyelinating lesions as two dimensional FLAIR and DE T2 sequences combined. A greater number of lesions were detected with the DIR sequence, and all lesions were more conspicuous. A single, stand alone DIR sequence may be considered appropriate for monitoring MS.

MRI of bilateral internal carotid artery agenesis

Bilateral internal carotid artery (ICA) agenesis is rare. A patient presented with symptoms of a transient ischaemic attack. Magnetic resonance imaging with magnetic resonance angiography showed multiple foci of chronic cerebral ischaemic change and bilaterally absent ICA. Cerebral supply was derived from the posterior circulation. Differentiation has to be made between congenital agenesis/hypoplasia and acquired ICA occlusion. Computed tomography through the skull base showed the absence of the carotid canals bilaterally confirming congenital ICA agenesis.

Multiple dural arteriovenous fistulas. Radiologic progression and endovascular cure. Case report

SUMMARY

Dural arteriovenous fistulas are most probably acquired lesions. However, they have been rarely encountered de novo.We present a unique case of a 71-year-old woman who initially presented with right-sided dural arteriovenous fistula (DAVF), which spontaneously resolved after diagnostic arteriography. She later developed asymptomatic occlusion of the left transverse sinus. Five years after her initial presentation she developed left-sided pulse-synchronous tinnitus. MRA and catheter angiography showed a complex type IV DAVF between the left transverse sinus and multiple dural branches arising from both left and right external carotid arteries. The left transverse sinus was isolated from the torcula herophili, with stenosis of the sigmoid sinus. Extensive cortical venous drainage was demonstrated. Endovascular cure was effected by polyvinyl alcohol particle and absolute alcohol occlusion of the dominant dural supply, and transvenous coil occlusion of the left transverse sinus. The patient's symptoms resolved almost immediately. This unique case demonstrates that dural sinus occlusion and DAVFs may co-exist, but there may not be a causal relationship. It is likely that both DAVFs and sinus occlusion are manifestations of the same disease process characterised by a pro-thrombotic state and secondary angiogenesis. It is important to recognise that changes in symptomatology, even long after apparent disappearance of a lesion may indicate recurrence, and careful follow up is advocated.

Endovascular treatment of intracranial aneurysms with Guglielmi detachable coils: analysis of midterm angiographic and clinical outcomes

BACKGROUND AND PURPOSE

The previous decade has witnessed increasing application of Guglielmi detachable coils (GDCs) for the treatment of intracranial aneurysms. However, the midterm angiographic and clinical outcomes are not well documented. We report here the angiographic and clinical outcomes of patients treated with GDCs over an 8-year period.

METHODS

Between 1992 and 1998, 144 patients with 160 intracranial aneurysms were treated with GDCs. Clinical follow-up data were obtained from medical records, questionnaires, and telephone interviews. Angiographic studies were reviewed by 2 neuroradiologists to obtain consensus regarding the degree of aneurysm occlusion.

RESULTS

Eighty-one patients had ruptured aneurysms; 63 had unruptured aneurysms. Technical success was achieved in 91% of patients, with complete aneurysm occlusion in 46%, neck remnants in 16%, and residual body filling in 38%. Angiographic follow-up revealed that residual body filling in some aneurysms was resolved, small neck remnants were stable, and the recanalization rate decreased with time. All 63 patients with unruptured aneurysms were discharged from hospital with independent clinical status (Glasgow Outcome Score, 1 or 2). For patients with ruptured aneurysms, discharge clinical status correlated with the Hunt & Hess clinical grade at the time of treatment. Clinical follow-up for a minimum of 2 years was available in 98.5% of patients. Ninety-four percent of patients treated for unruptured aneurysms were independent at 2 years, and 82% of Hunt & Hess grade I to II patients were independent.

CONCLUSIONS

Coil embolization is a safe and effective treatment for both ruptured and unruptured aneurysms. Increasing angiographic stability is demonstrated in treated aneurysms up to 3 years from coil embolization. Therefore, follow-up angiography until this time is advisable.

Use of glycoprotein IIb-IIIa inhibitor for a thromboembolic complication during Guglielmi detachable coil treatment of an acutely ruptured aneurysm

Thrombotic occlusion of the anterior communicating and right anterior cerebral arteries occurred during embolization of an acutely ruptured aneurysm of the anterior communicating artery. Traditional management, including superselective infusion of a fibrinolytic agent, was unsuccessful in reestablishing normal vessel patency. Therefore, an intravenous dose of abciximab was administered. Serial angiography showed that normal vessel patency was reestablished within 10 min. There were no adverse events related to abciximab administration, and the patient recovered from the procedure without neurologic deficit.

Carotid arterial stent placement: results and follow-up in 53 patients

PURPOSE

To describe the results, complications, and follow-up data after stent placement for occlusive internal carotid arterial disease and to compare the results with those in the literature.

MATERIALS AND METHODS

Carotid arterial stent placement was attempted in 57 arteries in 53 patients. Thirty-six (68%) of 53 patients were symptomatic. Forty-two (79%) of 53 patients had one to three clinically important comorbidities and were considered at high risk. All patients underwent pre- and postprocedural independent neurologic examinations. Follow-up consisted of serial duplex ultrasonography and clinical assessment.

RESULTS

The immediate technical success rate of stent deployment was 97%. Periprocedurally, three (three [5%] of 57 interventions) transient ischemic attacks and three (three [5%] of 57 interventions) minor strokes occurred. Two deaths occurred in the first 30 days (one myocardial infarction, one renal failure). One ipsilateral major stroke occurred 3 weeks after the procedure. The 30-day ipsilateral major stroke and death rate was 5% (three of 57 interventions). At 30 days, one of three patients with minor stroke had mild residual dysphasia. Treatment remained clinically successful in 48 (96%) of 50 patients. The restenosis rate was 4% (two patients).

CONCLUSION

Carotid arterial stent placement in a high-risk population has morbidity and mortality rates comparable to those of carotid endarterectomy in a lower risk population. Carotid arterial stent placement can be performed with a low restenosis rate.

Delayed aneurysm rerupture following total endovascular occlusion

Endovascular coiling is a well established technique for the treatment of selected intracranial aneurysms, but its long-term efficacy, including the rate of rehaemorrhage from treated lesions, remains to be clearly determined. We report a case in which the rerupture of a small aneurysm occurred 12 months after embolization, despite angiographic occlusion on immediate post-procedural and 6-month check angiography.

Acute spontaneous spinal subdural haematoma: MRI features

We present MRI findings in three patients with acute spontaneous subdural haematomas of the spine. Acute haematomas (1-3 days) were isointense or gave slightly high signal on T1-and heterogeneous signal on T2-weighted images. MRI precisely defined the level and extent of the haematoma preoperatively. The MRI was prospectively correctly interpreted as acute subdural haematomas in all patients. As a specific, noninvasive modality, MRI is the preferred imaging technique in this rare clinical entity.

Craniofacial mucormycosis following assault: an unusual presentation of an unusual disease

A case of craniofacial mucormycosis following assault is discussed. A female diabetic developed peri-orbital cellulitis adjacent to a scalp wound which progressed to a necrotizing fasciitis. This did not respond to treatment. Subsequently the patient developed a hemiparesis, with CT imaging showing peri-orbital and paranasal sinus inflammatory changes, evidence of cavernous sinus invasion and development of a middle cerebral artery territory infarction. The patient died shortly afterwards. The imaging findings and their relationship to the pathological spread of mucor infection are discussed.

Vertebral synovial osteochondromatosis with compressive myelopathy

STUDY DESIGN

A case report of vertebral synovial osteochondromatosis with compressive myelopathy.

OBJECTIVES

To describe the clinical, radiologic, and histopathologic features of vertebral facet synovial osteochondromatosis with compressive myelopathy.

SUMMARY OF BACKGROUND DATA

There has been only one previously reported case of synovial osteochondromatosis affecting the vertebral facet joint and no previous report of associated compressive myelopathy.

METHODS

The case history, radiology, surgical findings, and histopathology are reviewed.

RESULTS

Vertebral facet synovial osteochondromatosis is a potential and readily manageable cause of spinal cord compression.

CONCLUSIONS

Synovial osteochondromatosis of the vertebral facet joint should be considered as a cause of compressive myelopathy.

Resolution of third nerve paresis after endovascular management of aneurysms of the posterior communicating artery

The effect of endovascular treatment on the recovery of neural function in patients with third nerve palsy caused by an aneurysm of the posterior communicating artery is poorly documented. We report three cases in which third nerve paresis resolved completely within 2 to 3 weeks of endovascular occlusion of a posterior communicating artery aneurysm.

Thoracolumbar disc degeneration in young fast bowlers in cricket: a follow-up study

OBJECTIVE: To determine the progression of thoracolumbar disc degeneration in young fast bowlers in cricket. DESIGN: Prospective fast bowling technique and MRI follow-up study. BACKGROUND: Previous studies on high-performance young fast bowlers have found that lumbar spine pathology was related to the mixed bowling technique. METHODS: Nineteen young male fast bowlers (mean age 13.6 years) underwent MRI scans to detect the presence of intervertebral disc abnormalities. Subjects were also filmed laterally (200 Hz) and from directly above (100 Hz) whilst bowling two maximum velocity deliveries (session 1). Subjects were tested using an identical methodology 2.7 years later (session 2). RESULTS: At session 1, the incidence of thoracolumbar disc degeneration was 21%; however, at session 2, the incidence significantly (P = 0.008) increased to 58%. Furthermore the increase in the incidence of back pain between session 1 and session 2 was also significant (P = 0.002). The progression of disc degeneration was found to be significantly (P = 0.015) related to the group of fast bowlers who utilized the mixed technique during both session 1 and 2 when compared to those who used this technique during one session only. CONCLUSIONS: Thoracolumbar disc degeneration and back pain increase significantly during the time period examined in this study. Further, bowlers who utilize the mixed bowling technique stand a greater chance of developing degenerative changes of the spine.

Cost versus efficacy of magnetic resonance imaging

Magnetic resonance imaging offers new and improved diagnostic capabilities in all body parts and organ systems. Examinations can be quicker, safer and less expensive than traditional radiological procedures. The cost/efficiency of magnetic resonance imaging is under active evaluation.

A review of magnetic resonance imaging in spinal trauma

One hundred and ninety-five magnetic resonance (MR) images (1.5 Tesla) of 167 patients with neurological impairment following spinal trauma were reviewed. Acute cord injury produces central haemorrhagic necrosis that extends transversely and longitudinally with time and increased injury severity. Oedoma is more homogeneous, extensive and dominant in minimal lesions. Magnetic resonance appearances correlate with neurological status and outcome. Patients with MR evidence of cord blood had severe clinical lesions and failed to show useful clinical improvement. Patients with homogeneous 'oedema' improved to useful function. Lesion signal inhomogeneity relates to a worse prognosis. The clinical level correlates closely with cord blood or signal in homogeneity but imprecisely with homogeneous oedema. Disc herniations require differentiation from epidural blood and venous engorgement, which are prominent with bone displacement. Magnetic resonance is recommended in incomplete cord syndromes and in cord injuries with no apparent fracture, particularly if clinically deteriorating. Chronic injury consists of cavitation, extensive gliosis, cord atrophy and leptomeningeal fibrosis. Progressive myelopathy may result from cystic or non-cystic intramedullary lesions. Cord cysts are common and cyst fluid signal should closely follow cerebrospinal fluid. Turbulent cyst fluid motion is commoner in larger cysts and may predict those cysts more prone to propagate. Progressive syrinxes show typical appearances, usually with transverse septa. Atrophy and propagating syrinxes usually take years to develop. Leptomeningeal cysts and spinal stenosis caused by bone displacement and accelerated adjacent disc disease may cause late deterioration. In progressive myelopathy following injury, surgically drainable cysts are clearly differentiable from cord gliosis and atrophy.

Comparison of magnetic resonance imaging and computed tomographic discography in the assessment of lumbar disc degeneration

Eighteen patients with chronic low back pain were studied with magnetic resonance imaging (MRI) and computed tomographic (CT) discography. Each study was classified as being normal, showing early disc degenerative changes including annular tear, showing established disc degeneration or disc herniation. There was comparable information in over 90% of the MRI studies when compared to CT discography, without reliance on pain provocation or carrying out an invasive procedure. The axial and sagittal T1 weighted images were used to exclude other causes of pain, such as foraminal stenosis and disc herniation. The mid-sagittal T2 weighted image used in this study was considered to be, in part, responsible for the underestimation of disc degeneration because it did not allow visualization of the lateral aspects of the discs.

Craniopharyngioma and the moustache sign

Craniopharyngiomas are common suprasellar tumours but these are rarely associated with vasogenic oedema. Because the oedema extends into the optic tracts and optic radiations, a characteristic pattern is produced that resembles a moustache. The oedema is though to be due to leakage of craniopharyngioma contents. Such a case is presented in this communication.

Disc degeneration and the young fast bowler in cricket

Twenty-four male fast bowlers of mean age 13.7 years, who bowled competitively at a school and club level were selected from five Western Australian schools. At the time of the testing all bowlers, who were bowling completely freely, underwent magnetic resonance imaging to detect the presence of intervertebral disc abnormalities. While these radiological data were being analysed, the players were filmed both laterally (200 Hz) and from directly above (100 Hz) as their front foot impacted a force platform during the delivery stride of the fast bowling action. In addition these bowlers performed selected physical capacity tests. The occurrence of abnormal radiological data were then used to group the bowlers (group 1, no abnormal features; group 2, disc degeneration and/or bulging on scan). A Mann-Whitney U rank test was then used to identify any significant differences (P < 0.1) between the groups for all dependent variables. Five of the subjects recorded abnormal magnetic resonance imaging scans of the lumbar spine, while nineteen recorded normal intervertebral discs, normal alignment of the lumbar spine, and no sign of spondylolisthesis. Bowlers who rotated the trunk to realign the shoulders to a more side-on position between back foot impact and front foot impact in the delivery stride were more likely to record abnormal intervertebral disc features.

The effect of magnetic resonance imaging in a teaching hospital on patient management

An observational study was undertaken to obtain measures of the impact of magnetic resonance imaging (MRI) on diagnosis, patient management and patient outcome. A minimum data set at the time of examination was used for 1119 consecutive patients referred by specialists for MRI of the brain or spine. Three month follow up of 707 brain examinations and 235 spinal examinations was undertaken using a questionnaire on diagnosis and patient management. Magnetic resonance imaging made a dominant contribution to final diagnoses of neoplasia and vascular disorders, but was less significant for white matter disease. In a high proportion of cases other types of examination also influenced the final diagnosis. Magnetic resonance imaging affected patient management in a high proportion of spinal examinations and in cases of cerebral neoplasm, with lesser contributions to cases of cerebrovascular disorder and white matter disease. While MRI was considered superior to other imaging methods, which it could often replace, in practice it will form only one input to the diagnostic decision.

Moyamoya disease: no need for anastomotic surgery?

This paper describes an Australian of Caucasian descent with severe Moyamoya disease. She presented at the age of 34 with a subarachnoid haemorrhage. Between the ages of 45 and 48 she had multiple episodes of cerebrovascular ischaemia. Anastomotic surgery was carefully considered but not undertaken. Ten year follow up showed her to be extremely well without any further episodes of cerebrovascular disease. Accordingly it is recommended that surgery is probably not necessary in some cases, particularly in adults.

Cranial dural arteriovenous malformation and fistula. Radiological diagnosis and management. Review of thirty four patients

The clinical features, imaging and angiographic findings of thirty four patients with cranial dural arteriovenous malformations and fistulae are presented in four groups. Group 1--Seven patients with anterior cavernous malformations, predominant superior ophthalmic vein drainage, and symptoms and signs of carotico-cavernous fistula. Group 2--Twelve patients with malformations of the superior petrosal, transverse and sigmoid sinus regions, presenting predominantly with bruit. Group 3--Seven patients with malformations of the basal sinuses and prominent cortical venous drainage, presenting with intracranial haemorrhage, headache and impaired cortical function. Intracranial haemorrhage never occurred in the absence of cortical venous drainage. Group 4--Eight patients with infrequent manifestations. Group 1 and 2 patients are readily recognized and diagnosed. Group 3 and 4 patients are often misdiagnosed. Treatment modalities comprised embolisation therapy, surgical excision, and carotid compression. Twenty patients were treated by one or more of these modalities with a successful outcome in thirteen patients. Group 1 patients are the most amenable to trans-arterial embolisation. Carotid compression as the sole modality of treatment was successful in four patients. Unless the fistula is successfully closed, Group 3 patients and patients who present with cervical or thoracic myelopathy carry a grave prognosis. There is need for greater radiologist awareness of Group 3 and the rarer presentations, particularly myelopathy. With the exception of one patient, the morphological features of our cases are consistent with the now-accepted view that these lesions are acquired arterio-venous fistulae and not congenital malformations.

Cerebral and brain stem Langerhans cell histiocytosis

Two patients with central nervous system manifestations of Langerhans cell histiocytosis, both with brain stem involvement, are reported. The onset of symptoms was at an age when the diagnosis might not have been considered.

Cholesterol cysts of the petrous apex: radiological evaluation and surgical management

The clinical presentation, diagnostic features and surgical management of three cases of giant cholesterol cysts involving the petrous apex of the temporal bone are presented. The ability to reach a confident pre-operative diagnosis using magnetic resonance imaging (MRI) due to its greater soft tissue contrast resolution, multiplanar imaging capabilities and sensitivity to blood products is illustrated. The operation of transmastoid infralabyrinthine draining of the petrous apex is described and other possible approaches discussed.

MR imaging of abdominal aortic aneurysm

Eight patients with abdominal aortic aneurysms were evaluated with magnetic resonance imaging (MRI). The MRI findings were verified by surgery in five, compared with ultrasonography in eight, with computed tomography in four and with angiography in eight patients. The size and extent of aneurysm, presence of thrombus, size of the residual lumen and involvement of branch vessels were readily demonstrated by MRI. Whilst sonography should remain the screening procedure of choice in patients with suspected abdominal aortic aneurysms, this early experience suggests that MRI may prove to be a noninvasive and adequate means of evaluating patients prior to surgery.

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.