Ronald G. Grainger

Osmolality* of intravascular radiological contrast media

All current intravascular radiological contrast media are salts and produce solutions of very high osmolality--five to eight times that or tissue cells, plasma or tissue fluid (all of which have an osmolality of 300 mosmols per kg water). Erythrocytes and vascular endothelium are adversely affected by the high osmolality of intravascular contrast media, resulting in tissue anoxia and increased capillary permeability, the latter causing damage to the blood-brain barrier. Vasodilatation, systemic hypotension and osmotic hypervolaemia are generalized manifestations of the high osmolality of contrast media. New low osmolality contrast media have been synthesized, utilizing a non-ionizing radical (such as amide or amine) instead of the carboxyl group of a tri-iodinated substituted benzoic acid. Such examples are metrizamide (Amipaque) and Iopamidol (both non-ionic amides) and Hexabrix (salts of a mono-acid dimer). Early clinical evaluation suggests that these low osmolality solutions have major advantages in reducing pain, heat sensation and adverse reactions of angiography.

The New Low-osmolar Contrast Media: A Simple Guide

The rationale of the new, low-osmolality contrast media for intravascular use is briefly discussed and the technical and commercial data are assembled in a form which, it is hoped, will help radiologists to make their own comparisons and conclusions.

Intravascular contrast media—the past, the present and the future. Mackenzie Davidson Memorial Lecture, April 1981

Mr. President, Ladies and Gentlemen, I am greatly honoured by being invited to deliver this, the 57th Mackende Davidson Lecture, for this is one of the greatest distinctions that British radiology can bestow. James Mackenzie Davidson, born in 1856, graduated M.B., CM. in 1882 at Aberdeen University and became an ophthalmic surgeon at the Aberdeen Royal Infirmary. But he was much more versatile than a mere doctor of clinical medicine. Mackenzie Davidson was a great experimentalist and an enthusiastic proponent and public lecturer in the natural sciences. He was so greatly excited by Rontgens discovery of X-rays in November 1895, that he visited Rontgen at Wurzburg, Germany, a few months later. The very next year he left Aberdeen and moved to London to work as consultant surgeon at the Royal London Ophthalmic, Moorfields and Charing Cross Hospitals with particular responsibility to establish their departments of radiology. Mackenzie Davidson soon became an acknowledged leader of the fledgling profession of...

The effect of contrast media of low osmolality on the peripheral arterial blood flow in the dog

The intravascular contrast media in current use are solutions of salts of tri-iodinated substituted benzoic acids. Haemodynamic changes following injection of these contrast media are due mainly to their high osmolar concentration which is five to eight times physiological levels. In this study we compare the effect in dogs on femoral arterial flow following femoral arterial injection of three new low osmolality contrast media (Amipaque, Iopamidol and Hexabrix) compared to conventional contrast media (Coronary 280). Conventional salts such as Conray 280 cause a marked vasodilatation and increase in femoral blood flow to about twice pre-injection levels. The three new low osmolality contrast media cause much less vasodilation and increase in femoral blood flow (+32%). There was no significant difference between the effects of any of the three new media. The experiment suggests that any of three new low osmolality contrast media should be suitable for femoral arteriography as they cause much less vasodilatation (and therefore discomfort) than conventional contrast media. Our results do not indicate a preference for any of the three new contrast agents.

Complications of Cardiovascular Radiological Investigations

The complications of aortography and angiocardiography are reviewed. In these procedures there is a small but unavoidable risk to the patient. It is essential that there be critical clinical selection of patients for these investigations. The ultimate criterion should be that of possible benefit to the individual patient and not that of academic diagnostic exercise.

Paget's disease; active or quiescent?

Eight out of 20 patients suffering from Pagets disease showed radiological deterioration within the space of two years. In each of these cases there was local osteoporosis at the site of the progressive changes, viz. osteoporosis circumscripta (3), demarcation zone pathological fracture (2), incomplete fractures (2), pathological fracture in porotic bone (1). These features did not occur in any of the “quiescent” patients and we believe that they are closely related to activity of the disease and that they support the contention that bone destruction is the essential, earliest and most active phase of Pagets disease.

The pulmonary circulation: The radiology of adaptation

In this George Simon Lecture, I have tried to present a simplistic yet philosophical approach to the physiological processes of adaptation of circulatory and respiratory function in response to pathophysiological challenge. The objective of the body is to achieve a normal ventilation-perfusion ratio of 1 in order to optimise blood-gas exchange in a wide variety of pathological conditions. It is all a question of the right ingredients (oxygen in atmospheric air and reduced haemoglobin in desaturated blood), in the right copious amounts (100 ml/s), in the right proportion (1:1) and in the right place (alveolar capillary membrane). In order to demonstrate the above concepts, a variety of well known conditions, congenital and acquired, have been discussed in the developing infant lung and the adult mature lung; some primarily cardiovascular, others primarily respiratory; some conditions resulting in permanent and others resulting in temporary and reversible major readjustments of the blood supply to the lung. The emphasis has been to illustrate that simple, unsophisticated radiological techniques may provide a substantial amount of valuable information concerning the remarkable capacity of the pulmonary circulation to adapt to varying physiological or pathological demands in order to conserve our precious respiratory resources. George Simon, like all good doctors, had a tremendous respect for the ability of the body to respond to these challenges. He always emphasised the important basic principles rather than fine minutiae. It is hoped that this lecture in his honour follows these principles which he preached so well.

NEW CARDIOVASCULAR CONTRAST MEDIA: SODIUM IOTHALAMATE (ANGIOCONRAY) AND METHYLGLUCAMINE IOTHALAMATE (CONRAY). COMPARATIVE OBSERVATIONS ON VARIOUS CONTRAST MEDIA IN ANGIOCARDIOGRAPHY.

1. Two new radio-opaque intravascular contrast media are described. These are the sodium and the methylglucamine salts of iothalamic acid, which is an isomer of diatrizoic acid. 2. The 80 per cent solution of sodium iothalamate (Angio-Conray) is crystal clear even at 0°C, has a low viscosity and a high iodine content. Experimental studies indicate that a higher injection rate of iodine can be achieved with AngioConray 80% than with previously available media. This has resulted in a considerable improvement of the radiographic quality of hand-injected catheter and needle aortographic quality of hand-injected catheter and needle aortographic studies. There has been a lesser but appreciable improvement in angiocardiographic studies employing high pressure injections through small bore catheters. 3. The toxic reactions encountered in 214 angiocardiographic and aortographic injections of AngioConray 80% are described. 4. A small pilot series including 124 carotid, 48 femoral arteriograms and 50 lumbar aortogra...

A CLINICAL TRIAL OF ORAL CHOLECYSTOGRAPHIC MEDIA: TELEPAQUE, BILOPTIN, OSBIL TABLETS AND OSBIL CAPSULES.

478 patients were each given one of four oral cholecystographic contrast media, Biloptin, Telepaque and two preparations of Osbil. The four media are compared with regard to the toxic reactions encountered, the degree of opacification of the gall-bladder, the visualisation of the bile-duct system and the presence or absence of contrast medium in the bowel. The findings are compared with those of other workers.

The optimal concentration of contrast medium for aortography and femoral arteriography: A comparison of hexabrix 320 and hexabrix 250

A prospective double-blind randomised clinical trial of aortography and iliofemoral arteriography in 89 patients demonstrates that there is no difference in the diagnostic quality of the studies when Hexabrix 250 replaces Hexabrix 320. There is a minor reduction in patient subjective reaction, and the lower viscosity permits the use of smaller bore catheters. The major gain is that the cost of the contrast medium should be reduced by 22%.