Compliance with the Royal College of Radiologists' guidelines on the use of pre-operative chest radiographs.

Clinical compliance with the Royal College of Radiologists' guidelines on the use of pre-operative chest radiology was examined in a random sample of patients in four hospitals in England and Wales. Pre-operative clinical data were abstracted from medical reports and, in one hospital, from special chest radiograph request forms completed by clinicians. Seventy-five per cent of patients had clinical indications warranting a pre-operative chest radiograph. This level of compliance is compatible with that found with other guidelines and would suggest that the pre-operative chest radiograph guidelines are suitable for wider implementation in the National Health Service.

Multicentre trial of four strategies to reduce use of a radiological test.

The Royal College of Radiologists' guidelines on the use of pre-operative chest X-rays were implemented for 1 year in four hospitals in England and Wales. The strategies adopted were: (1) the appointment of a utilisation review committee; (2) getting feedback on use to consultants; (3) the introduction of a new chest X-ray request form; or (4) the concurrent reviewing of chest X-ray requests by the radiology department. The lowest level of use (8.5 pre-operative chest X-rays per 100 elective operations) was achieved with the utilisation review committee after it displayed the guidelines in surgical wards. Information feedback produced a consistent reduction from 29.4 to 13.3 X-rays per 100 operations. Both the new request form and concurrent review had a moderate and intermittent effect. No change in practice occurred in a control hospital.

Radiography in the home.

Modern portable x-ray units are light enough to be easily carried to the ill patient in his home; their output is sufficient for radiographs containing useful diagnostic information to be made of the chest, hip, and other regions, especially if a grid is employed. The skull is considered to be beyond the range of this method of examination, because of the long exposure times required, but gross lesions can be demonstrated in the oesophagus and stomach if barium is given. The radiation hazard is not considered to be a contraindication if appropriate precautions are taken.

Correlation of intra-arterial contrast stasis with flow patterns at constrictions, branches and bends: an experimental model.

Flow patterns at bends and branches have been studied in an easily constructed open channel model so as to determine whether zones of stasis and poor mixing at constrictions, bends and branches can be correlated with certain arteriographic appearances. At bends, spiral flow lines and static zones occur which resemble those seen occasionally in the aortic arch and carotid siphon. At branches, stasis occurs on the outer walls of the branch mouths both in the experiments and arteriography, and constrictions easily produce downstream stasis, previously demonstrated in both arteries and open-channel experiments. Upstream stasis, not previously recorded, can also occur in arteries and model associated with severe constrictions. Occasionally stasis may extend along the whole length of one wall of a vessel when there is a downstream constriction, resembling arteriographic appearances seen in the internal carotid artery in patients with raised intracranial pressure, in those undergoin hyperventilation and also in coronary and other arteries. Despite known rheological differences between blood and water, the experimental findings are thought to be meaningful, and to indicate that there are within arteries, areas where turbulent mixing forces are weak or absent, resulting in arterial stasis.

Tricle arteriography: demonstration of thrombi in the origen of the internal carotid artery.

Thrombi developing within the origin of the internal carotid artery may be demonstrated by a slow trickle injection of highly concentrated contrast medium, which lingers in pools around the thrombus on the dependent wall of the vessel. With this technique thrombi have been detected which could not be visualized on conventional arteriography because they were obscured by the density of the vascular shadow produced by the forceful injection usually employed in carotid angiography. In addition, trickle arteriography is useful for assessing the position and extent of atheromatous plaques and the contrast stasis associated with them.