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Background and Purpose: Our objective was to compare the reliability of CT venography with intraarterial digital subtraction angiography (DSA) in imaging cerebral venous anatomy and pathology., Methods: In 25 consecutive patients, 426 venous structures were determined as present, partially present, or absent by three observers evaluating CT multiplanar reformatted (MPR) and maximum intensity projection (MIP) images. These results were compared with the results from intraarterial DSA and, in a second step, with the results of an intraobserver consensus. In addition, pathologic conditions were described., Results: Using DSA as the standard of reference, MPR images had an overall sensitivity of 95% (specificity, 19%) and MIP images a sensitivity of 80% (specificity, 44%) in depicting the cerebral venous anatomy. On the basis of an intraobserver consensus including DSA, MPR, and MIP images (415 vessels present), the sensitivity/specificity was 95%/91% for MPR, 90%/100% for DSA, and 79%/91% for MIP images. MPR images were superior to DSA images in showing the cavernous sinus, the inferior sagittal sinus, and the basal vein of Rosenthal. Venous occlusive diseases were correctly recognized on both MPR and MIP images. Only DSA images provided reliable information of invasion of a sinus by an adjacent meningioma., Conclusion: CT venography proved to be a reliable method to depict the cerebral venous structures. MPR images were superior to MIP images.

In epileptic seizures, the sensitivity of CT and MRI depends on different underlying pathologies and varies according to the age of the patient and the type of seizure. The different modalities are discussed in detail.

The characteristic findings on computed tomography (CT) in multiple sclerosis (MS) are discussed. In a series of 49 cases plain CT was normal in 21 (43%), cerebral atrophy alone was present in 17 (35%) and plaques were visible in 11 (23%). These were most often adjacent to the lateral ventricles (14 plaques) and in the parietal white matter (10 plaques). CT was performed after the intravenous administration of iodide in 16 of these cases. Three of the low attenuation and three additional isodense lesions enhanced. Two patients with low attenuation plaques were scanned with xenon enhancement; the plaques absorbed less xenon than the corresponding contralateral brain substance and additional, previously isodense plaques were revealed. In one case the white matter absorbed much less xenon than normal and its uptake relative to grey matter was reduced.

A subdural haematoma is described in which a definite computed tomographic (CT) scan diagnosis was made only after contrast enhancement had been achieved by the inhalation of xenon. The different types of enhancement obtained with iodide containing contrast media and with xenon are discussed. The use of xenon to obtain further information in conditions which are inadequately elucidated by conventional CT must be balanced against its anaesthetic effects and relatively high cost.

The CT and angiographic appearances in multi-infarct dementia have been compared with those of primary neuronal degeneration. It was possible to make a CT or angiographic diagnosis of multi-infarct dementia in about 40% of patients diagnosed by the ischaemic scoring method of Hachinski et al.

Two different types of retrospective study of the value of CT have been contrasted. In one, the patients were chosen because of the way they presented (with posterior fossa signs of symptoms) or because they were found to have posterior fossa disease; in the other, all were reported as having, or found to have, gliomas or metastases. The first type of study provides a better basis for evaluation of neuroradiological procedures.

Forty-nine patients with clinical features of vascular disease in the vertebrobasilar territory were examined to evaluate the diagnostic performance of computed tomography. It provided useful information in the diagnosis of acute vascular lesions in patients in whom a definite episode had occurred not longer than 2 weeks before computed tomography was undertaken. It was of value in both haemorrhagic and thromboembolic groups but in many patients angiography was required to make a substantive diagnosis. It was of less value in patients with vague and ill defined symptoms and of no value in transient ischaemia.

Two patients are described in whom computerised tomography revealed contrast-enhanced lesions in the early stages of multiple sclerosis. Such lesions may be differentiated from tumours by their transient nature, lack of space-occupying effect, and localisation in the white matter. Contrast enhancement in demyelinating disease is probably related to local breakdown of the blood-brain barrier.

Computed topography (CT) before and during xenon enhancement and computer subtraction has been performed in 11 patients with intracerebral tumours and 7 with ischaemic lesions. The amount of xenon uptake was expressed where possible as a percentage of that in the corresponding region of the contralateral apparently normal hemisphere. The amount of xenon uptake did not appear to be specific for any particular tumour histology. The margins of tumours were better defined during enhancement, but not to a degree which affected management; large cysts did not enhance and were well demonstrated. Cavities due to mature infarcts did not enhance and the central parts of most large recent infarcts showed markedly diminished enhancement. In recent infarcts delayed xenon uptake at the periphery and sometimes throughout the lesion reflects diminished perfusion of potentially viable tissue. One patient with an ischaemic parietal lesion in which xenon uptake was normal made a complete clinical recovery.

The typical computed tomographic (CT) features of a recent intracerebral haematoma are a homogenous region of increased attenuation surrounded by a well demarcated relatively narrow low attenuation ring (LAR). The pathology of the LAR is controversial, but it corresponds well with a zone of ischaemic necrosis which is observed around most intracerebral haematomas exmined at autopsy. Observations are made on spontaneous intracerebral haematomas and on blood samples which confirm that extravasated blood clot undergoes a variable degree of retraction which is completed within six hours. This suggests that the LAR in recent haematoma is due to damage caused by the greater volume of the precontracted haemorrhage on the surrounding brain. CT abnormalities in intracerebral haematomas were studied; features which were useful in distinguishing spontaneous haematomas and those which affected prognosis are discussed.

The contribution of plain X-rays to the management of 170 patients suspected or actually found to have posterior fossa disease has been retrospectively assessed. A useful contribution was made in 4%.