Mad cows and Englishmen.

This article examines the unfolding crisis in the beef industry during the first few days of the story becoming public, and examines the response of the British government to the crisis. It looks at the reasons why, despite prompt action by government ministers, the issue became one of massive loss of public confidence, and it draws general lessons from the beef crisis for modern health communication practice. The article argues that governments will fail to keep public confidence in public health issues unless they allow the public to judge issues on all available facts, and act in response to public judgments.

Digital subtraction angiography (DSA) of the extracranial cerebral vessels: a direct comparison between intravenous and intra-arterial DSA.

Fifty patients being investigated for ischaemic cerebrovascular disease underwent both intravenous digital subtraction angiography (IV-DSA) and intra-arterial arch digital subtraction angiography (arch-DSA) to enable a direct comparison to be made between the two techniques. The overall quality of the images obtained by arch-DSA was better than that obtained by IV-DSA, but there was no significant difference between the number and gradation of stenoses detected by the two techniques. No significant stenosis was missed by IV-DSA and the technique was found to be sufficiently accurate for it to be used as a screening procedure for carotid bifurcation stenoses suitable for carotid endarterectomy. The advantages and limitations of both techniques are discussed.

The value of CT scanning in chronic suppurative otitis media.

High definition CT has been advocated for the evaluation of chronic suppurative otitis media (CSOM) either generally or in selected cases. It is said to be capable of producing the fine detail needed to detect lateral canal fistulae, exposed dura and facial canal dehiscences, and to demonstrate the ossicular chain. At present there is no agreement on either the indications for CT scanning in CSOM or the most appropriate scanning plane. To determine the value of high definition CT in CSOM and to decide a unit policy for its application, 36 cases of CSOM underwent pre-operative CT scanning and their scans were compared with the operative findings. Our results show CT to be highly sensitive to the presence of soft tissue disease and bone erosion, moderately sensitive to the presence of lateral canal fistulae but less sensitive to the presence of small areas of exposed dura, ossicular continuity and facial canal dehiscence. Axial scans were better able to demonstrate the lateral canal but otherwise coronal scans were superior; ideally patients should be scanned in both planes. The principle value of CT in CSOM is its ability to demonstrate disease which is not clinically apparent.

Digital subtraction angiography (DSA). Work load and financial implications for a neuroradiology department.

A four year study has been undertaken into the effects on the workload and cost implications of the introduction of digital subtraction angiography (DSA) in a large United Kingdom teaching hospital. The increase in workload has been entirely due to the ability to perform intravenous angiography. DSA is cheaper than conventional angiography if more than 210 cases are undertaken each year. This difference is accounted for by the reduced use of X-ray film. However, intravenous angiography is more expensive because of the use of large volumes of nonionic medium.

Stereotactic brain biopsy using a narrow aperture computed tomography scanner.

A technique for stereotactic brain biopsy with guidance by computed tomography (CT) has been developed and the procedure carried out on a series of 12 patients. A head fixation device, based on the Leksell method, has been designed which allows exact transfer of CT co-ordinates to a Bennett stereotactic frame for the purpose of the biopsy. The development and initial experience of this stereotactic technique in 12 cases is reported and the accuracy of the method confirmed by histological examination and post-operative CT verification of the biopsy site, by means of a small marker inserted at the time of surgery.

Significance of tomography in Meniere's disease: visualization and morphology of the vestibular aqueduct.

The revival of endolymphatic sac surgery has led to many investigations in Meniere's disease, including lateral tomography of the vestibular aqueduct. Contrary to recent literature, we found no difference in the presence and morphology of the vestibular aqueduct when assessed radiologically in a group of Meniere's patients and a control group. Our assessment of this information in regard to etiology and treatment of Meniere's disease is presented.

Significance of tomography in Meniere's disease: periaqueductal pneumatization.

The revival of endolymphatic sac surgery has led to many investigations in Meniere's disease, including lateral tomography of the periaqueductal pneumatization. We radiologically assessed a series of Meniere's patients and a control group, and found hypocellularity to be more common in Meniere's disease as the literature has stated. However, we found this finding bilaterally in patients with unilateral disease. Our assessment of this information in regard to the etiology and treatment of Meniere's disease is presented.

Determination of cerebral blood flow with the EMI CT scanner.

Cerebral blood flow (CBF) detemination were made in seven baboons and two patients with the EMI CT dedicated head scanner. The method for determining the CBF was tested and measurements were made during physiological states elicited by changes in pCO2 and depth of anaesthesia. The method has a number of advantages, particularly for assessing CBF responses to pCO2 changes.

The clinical significance of pneumographic cerebellar atrophy.

The clinical significance of apparent pneumographic cerebellar atrophy has been studied in a group of 44 otherwise unselected patients found to have cerebellar atrophy, according to previously suggested criteria, at pneumoencephalography. Lateral and postero-anterior tomography of the posterior fossa was performed in all these cases. In each case the width of two or more sulci in the cerebellar vermis exceeded 2 mm. We have concluded that: (1) There is a relationship between the severity of pneumographic cerebellar atrophy and the severity of clinical signs of cerebellar disease (p = 0.03). (2) Severe or moderate atrophy of the vermis, whether generalized or focal, is usually associated with clinical signs of cerebellar disease, but mild atrophy of the vermis, equivalent to the "moderate" atrophy of previous studies, has no apparent diagnostic significance. (3) Atrophy of the cerebellar hemispheres, in the absence of atrophy of the vermis, is very unusual and it cannot, by itself, be correlated with clinical signs of cerebellar disease. (4) In individual cases, assessment of the significance of pneumographic cerebellar atrophy cannot be made without adequate clinical information.

Cardio-respiratory changes during pneumoencephalography.

Carbon-respiratory changes associated with changes in posture and injection of intrathecal oxygen were studied in fifeen patients undergoing pneumoencephalography in a Phillips isocentric chair, while breathing spontaneously and anaesthetised with halothane in oxygen. Haemodynamic changes associated with changes in posture were of a minor nature. A rise in PaCO2 occurred in the prone position in two obese patients. There were significant rises in blood pressure following injection of more than 5 ml of oxygen as a bolus into the subarachnoid space.

Cerebral angiotomography.

This study was undertaken with two main objectives: (a) to ascertain in the practicability of two simple types of apparatus and (b) to evaluate the clinical situations in which the procedure was most likely to be helpful. Aneurysms, arteriovenous malformations, vascular diseases, tumors, including pituitary tumors, and head injuries were studied. The technique was found to be most useful in aneurysms, arteriovenous malformations and pituitary tumors.

Results of the use of a new water-soluble contrast medium (metrizamide) in the posterior fossa of the baboon.

An investigation was made of the use of a new water-soluble contrast material (metrizamide) for posterior-fossa radiography in the baboon. The experiments showed that the concentration of metrizamide needed to produce adequate radiographs from sub-occipital injections into the posterior fossa always produced generalized seizures. Intraventricular injection produced excellent radiographs from metrizamide concentrations, which did not result in either clinical or EEG seizure activity. Seizures, when they occurred, were easily controlled with pentobarbitone and phenytoin. In all the experiments, ECG changes were found, which disappeared after some hours.