Correlation of postmortem MRI and CT appearances with neuropathology in brain trauma: a comparison of two methods.

Postmortem magnetic resonance (MR) scans were performed on the brains of 12 victims of fatal head injuries. These were compared with neuropathological studies of the entire brain. The first six subjects were imaged with the brain in situ and comparison was also made with antemortem computed tomography (CT). The brains from the subsequent six subjects were removed at autopsy, fixed in formalin and then imaged in a mitre box designed to overcome the problems encountered in the pilot study. Although both CT and MR imaging (MRI) detected all clinically relevant haemorrhagic lesions, many pathologically significant lesions were missed. MRI detected many more lesions than CT, but still failed to visualize areas of non-haemorrhagic axonal injury.

Cavernous haemangiomas (angiomas) of the brain: clinically significant lesions.

A review of 2000 consecutive magnetic resonance imaging (MRI) brain studies identified 18 (0.9%) patients with lesions that satisfied MRI criteria for cavernous haemangiomas. The clinical, computed tomography (CT) and MRI findings in 23 patients with probable cavernous haemangiomas were compared. Thirty-three lesions were identified with multiple lesions in five (22%) patients. In 19 (82%) patients the neurological presentation corresponded to a cavernous haemangioma. The presenting symptoms were: seizures in 11 patients (48%); progressive neurological symptoms and signs in four (17%); and acute symptoms and signs due to haemorrhage in four (17%). T2 weighted images suggested the diagnosis in all cases, with 24 (73%) lesions showing the typical appearance of an area of mixed signal intensity with a rim of low signal intensity. In the absence of acute haemorrhage, CT demonstrated well circumscribed, round or oval hyperdense lesions without significant mass effect and with normal surrounding brain tissue in the majority of cases. Although not diagnostic, these CT features are strongly suggestive of cavernous haemangiomas.

Neuroradiologic findings in AIDS: a review of 200 cases.

The radiologic studies of 200 consecutive AIDS patients with neurologic symptoms were evaluated to determine their diagnostic specificity and prognostic value. Of 81 patients with initially normal CT scans, four (5%) later developed progressive neurologic illness. Of 75 patients with CT evidence of diffuse cerebral atrophy, 12 (16%) later developed CT abnormalities or had postmortem CNS disease. CT scans showed mass lesions initially in 44 patients and later in an additional seven patients. Although toxoplasma gondii infection was the most frequent cause of these lesions, the CT characteristics of cerebral toxoplasmosis are too nonspecific to warrant diagnosis without biopsy. Preliminary evidence suggests that MRI may be more sensitive than CT in detecting intracranial disease in patients with AIDS.

Meningovascular syphilis: CT and MR findings.

The radiologic findings in three cases of meningovascular syphilis are presented. Angiography demonstrated varying degrees of narrowing and ectasia of the supraclinoid carotid, basilar, and proximal anterior and middle cerebral arteries, as well as distal branches. Computed tomography (CT) showed multifocal infarction with variable enhancement. Similarly, in the one case studied with magnetic resonance (MR), several regions of high signal intensity on T2-weighted sequences were found, which were compatible with foci of ischemia. Although the radiologic findings are nonspecific, the diagnosis of meningovascular syphilis should be considered in patients with vasculitis of uncertain etiology.

Hydatid cyst: an unusual cause of diplopia.

A 59-year-old man presented with double vision due to vertical displacement of one eye by an infraorbital mass that indented the globe. Some 10 years previously he had had a Caldwell-Luc antrostomy for chronic sinusitis. Following investigation, the antrostomy was revised and an orbital cyst with a histological appearance suggestive of a mucocele was excised via an anterior inferior orbitotomy. The orbital mass recurred with identical symptoms some 18 months later with a second mass confluent with the first, presenting subcutaneously through his zygoma. A further radical antrostomy was performed enabling a diagnosis of a hydatid cyst of the antrum to be made. The unusual features of this rare cause of diplopia are discussed and illustrated. The literature on orbital hydatid cysts is reviewed and recommendations made as regards adequate surgical exposure and not irrigating orbital cysts with noxious agents.

Carrier detection in Duchenne muscular dystrophy using computed tomography.

In Duchenne dystrophy computed tomography of muscles shows total or partial replacement of normal muscle by low density tissue, presumably representing fat. It was hypothesised that female carriers would have increased fat deposition, and hence lower density readings in certain muscle groups when compared with controls. Three C.T. scans, two through the thigh and one through the calf, were obtained on 9 obligate carriers, 12 "possible" carriers, and 10 controls. A total of 15 density readings in different muscle groups were obtained for each subject. The results, analysing the mean densities in Hounsfield units, show that the obligate carriers have statistically significant lower density readings than controls. The 9 obligate carriers and 10 controls were correctly allocated using discriminant function analysis of muscle density readings. An attempt to assign the "possible" carriers was made. The use of C.T. scanning in addition to creatine kinase (C. K.) estimations will significantly improve accuracy of genetic counselling and has the advantage of being non-invasive.

Progression of muscular dystrophy assessed by computed tomography.

To determine whether computerised tomography (CT) offers an accurate means of following the progression of Duchenne muscular dystrophy, CT scans through the thigh and calf were done on two occasions, six months apart, for 13 boys with the disease. The results suggest that CT scans of muscles may be used as an adjunct to other methods in the accurate assessment of progression.

Lumbar myelography today. Experience with metrizamide, a water-soluble, non-ionic contrast medium.

A clinical assessment of metrizamide (Amipaque) lumbar myelography in 150 patients is reported, and the adverse reactions encountered are presented and discussed. Minor adverse reactions--headache (48%), nausea (10%) and vomiting (7%)--were common, and the incidence reflected overseas experience. Severe headache occurred in a significant proportion of patients (20%), despite adequate hydration and the use of a small-gauge needle. There were no major adverse reactions such as epilepsy or severe muscle spasm. The study suggests that metrizamide is well tolerated, gives good anatomical demonstration and should replace iophendylate (Myodil) in this region. Recent reports of occasional, but sometimes severe, neurological complications indicate that further cautious assessment is required.

Nocardia cerebral abscess: New concepts in diagnosis, management, and prognosis.

Three cases of multiple cerebral nocardial abscess are presented. All were cured by a combination of chemotherapy and surgery, a unique experience. Early detection, appropriate chemotherapy, absence of underlying immune malfunction, and surgically remediable disease are good prognostic indices in cerebral nocardiosis. If other adverse prognostic factors are absent, however, multiple abscess formation does not preclude the possibility of cure. Accurate localisation of nocardia cerebral abscesses by computerised axial tomography is a great help in management if multiple lesions are present.

Computed tomography of abdominal aortic aneurysms.

Computed tomography is an excellent non-invasive method for visualization of the size and extent of abdominal aortic aneurysms. It demonstrates the size of the lumen and the amount of thrombus in the aneurysm, and detects complications such as dissection and leakage.

Hypertension due to a renin-secreting tumour localised by segmental renal vein sampling.

An 18-year-old female was found to be hypertensive on routine medical examination. Further investigation disclosed persistent hypokalaemia and elevated plasma renin activity in peripheral venous blood. Segmental renal vein sampling with assay of blood samples located the source of excess renin secretion in the lower mid-zone of the left kidney. This localization was not confirmed by either angiography or by palpation of the exposed kidney before nephrectomy but macroscopic examination of the freshly sectioned kidney revealed a small tumour in the region suggested by renal vein sampling. The tumour had the morphologic pattern fo an haemangiopericytoma with abundant ultrastructural specific granules and very high renin activity by tissue assay. Plasma renin activity fell precipitously after nephrectomy and remained very low for the first week. Although the immediate post-operative blood pressure fell to normal, hypertension recurred temporarily and was associated with elevated plasma aldosteron, producing a syndrome similar to primary aldosteronism. All variables returned to normal without specific therapy and hypertension has not subsequently recurred.