A national survey of radiological complications: interim report

Drug provocation tests (DPTs) of contrast media: Useful or not useful? - A narrative review

Drug provocation tests (DPTs) are also used in some patients with a history of a contrast medium (CM)-hypersensitivity reaction. Since the use of contrast agents requires special knowledge that is present in radiology but not necessarily in allergology, this overview should close the knowledge gaps. The literature, and the package inserts of the industry dealing with DPTs in contrast hypersensitivity reactions was analyzed and the results presented. Historical analyses revealed that provocation tests were already done in the past, and called pre-testing. Due to disadvantages, this diagnostic tool was abandoned. A few years later, DPT was introduced as an innovative diagnostic procedure. The DPT has the 3 main disadvantages: a missing standardization, patients at risk (such as compromised renal function) are rarely taken into account, and a negative DPT does not exclude a subsequent CM reaction. DPTs (formerly called pre-testing) are a well-known method for diagnosing CM-related hypersensitivity reactions. Since the disadvantages of this diagnosis outweigh the advantages, we propose replacing DPT with routine contrast-enhanced imaging examination in radiology.

Intravenous Contrast-Induced Nephropathy-The Rise and Fall of a Threatening Idea

Contrast-induced nephropathy (CIN) has been considered to be a cause of renal failure for over 50 years, but careful review of past and recent studies reveals the risks of CIN to be overestimated. Older studies frequently cited the use of high-osmolality contrast media, which have since been replaced by low-osmolality contrast media, which have lower risks for nephropathy. In addition, literature regarding CIN typically describes the incidence following cardiac angiography, whereas the risk of CIN from intravenous injection is much lower. Most of the early published literature also lacked appropriate control groups to compare to those that received iodinated contrast, and thus attributed rises in creatinine to intravenous contrast without considering normal creatinine fluctuations (frequent in patients with kidney disease) and other acute pathologic states such as hypotension or nephrotoxic drug administration. The aim of this paper is to review the literature detailing CIN risk, discuss why CIN risk is often overestimated and how withholding contrast can lead to misdiagnosis and delay in appropriate patient management.

Estudo comparativo dos meios de contraste baritado e iodado-iônico e não-iônico no trato respiratório de ratos

OBJETIVO: Durante estudos radiológicos pode ocorrer a passagem do meio de contraste para a árvore traqueo-brônquica, determinando reações adversas e até fatais. O objetivo deste estudo é conhecer as alterações desencadeadas no trato respiratório pela presença do meio de contraste. MÉTODOS: Utilizaram-se 91 ratos divididos, aleatoriamente, em 4 grupos. Um grupo de controle não manipulado com 7 animais e os demais grupos com 21 ratos. O grupo controle manipulado recebeu solução fisiológica e os grupos de experimento: bário, iodo ônico e iodo não iônico conforme o grupo a que pertenciam. Sob anestesia e visibilização direta da traquéia, injetou-se 0,75 ml/kg (0,25 ml) do meio de contraste de acordo com o grupo ao qual pertencesse o animal. Realizaram-se as aferições com 1 hora, 1 dia e 1 semana. Os ratos foram sorteados para a autanásia nos três tempos estudados. Fez-se documentação radiográfica seguida da ressecção dos pulmões e exame histo-patológico. RESULTADOS: Na primeira hora, no grupo que recebeu bário, os campos médios e o superior direito ficaram acometidos. Nos grupos que receberam iodo iônico e iodo não iônico, todo o pulmão direito mostrava-se opacificado. Nas avaliações de uma dia e 1 semana os grupos que receberam iodo estavam normais enquanto que o grupo que recebeu bário mostrava comprometimento dos campos médios. No estudo histo-patológico observou-se, no grupo que recebeu bário, na avaliação de uma semana, grande quantidade de macrófagos intra-alveolares, perivasculares e peribrônquicos. CONCLUSÃO: Os contrastes iodados iônico e não iônico levam a alterações passageiras enquanto que o bário promove reação inflamatória crônica com manutenção da tradução radiográfica, no rato.

The histological response of the lungs of rats to potentially suitable water soluble bronchographic contrast agents iotrolan (a non-ionic dimer) and iopamidol (a non-ionic monomer)

The recent need for selective bronchography during bronchoscopy in certain patients, together with paediatric indications for tracheo-bronchography, raises the question as to which contrast medium is both safe and efficient. The purpose of the present experimental study was to define the tissue reaction caused by iotrolan and iopamidol in the bronchi and lungs of rats. 60 animals used in this study were divided into five groups receiving iotrolan 300, iopamidol 370, iopamidol 150, physiological saline and anaesthetic only, the last two acting as control groups. Statistically there was no significant difference in the histological reaction between iotrolan 300, iopamidol 370 and iopamidol 150 compared with the control groups, although iotrolan 300 appeared to result in the least tissue reaction. With its adequately high iodine concentration, low osmolality and relatively high viscosity, iotrolan 300 would appear to be a suitable contrast medium for bronchography.

Limitations and dangers of gastrografin swallow after esophageal and upper gastric operations

In a series of 135 patients who underwent esophageal and upper stomach surgery, the incidence of anastomotic leakage was 20.4 percent. One hundred four patients had either Gastrografin swallow or the methylene blue test to evaluate anastomotic integrity before resumption of oral feeding. Both tests were disappointing in that methylene blue failed to detect any case of leakage and Gastrografin swallow could only detect three cases of subclinical leakage. The high false-negative detection rate of Gastrografin swallow might be related to the inferior radiographic detail provided by this contrast medium. Aspiration of Gastrografin is potentially dangerous and could be fatal. We believe that barium sulfate, which provides better radiographic detail and is not so hazardous when aspirated, should be the contrast medium of choice.

Clinical use of Hexabrix for radiological evaluation of leakage from the upper gastrointestinal tract based on experimental study

The clinical use of Hexabrix (May and Baker) was started about 3.5 years ago for the radiological evaluation of patients in whom the possibility of leakage of contrast medium outside the upper gastrointestinal tract, particularly the oesophagus, was anticipated. The majority (greater than 70%) of the patients were in their early post-operative period. No adverse reactions because of the use of Hexabrix were encountered.

Iopamidol in the diagnosis of suspected upper gastro-intestinal perforation

Forty patients, mainly post-operative, were examined for suspected leakage from the oesophagus and/or stomach using iopamidol. Oesophageal leaks were demonstrated in seven patients, tracheo-oesophageal fistulae in two and an unsuspected gastro-jejunostomy intusussception in one. Only two cases were regarded as technically unsatisfactory due to poor coating. Normal examinations were found in 28 (70%) patients. This was confirmed by the subsequent clinical course. Aspiration into the bronchial tree occurred in five (12.5%) patients without ill-effects. Furthermore no adverse side effects as a result of the administration of iopamidol were recorded. It is concluded that a non-ionic medium such as iopamidol is the agent of choice in the detection of oesophageal and gastric perforation, particularly in post-operative patients where there is an increased risk of aspiration.

Experimental evaluation of various available contrast agents for use in the gastrointestinal tract in case of suspected leakage. Effects on pleura

Intrapleural injections of seven contrast agents were carried out in experimental rats in order to find a safe contrast agent to use in the radiological examination of the upper gastrointestinal tract in cases where leakage outside the upper gastrointestinal tract into the pleural space could be suspected, particularly post-operatively. The contrast agent in such cases could enter the mediastinum, pleura, peritoneum or lungs and bronchi. Hexabrix (May and Baker) and Gastrografin (Schering AG) produced the least tissue reaction in the pleura. Due to the potential risk of aspiration in such cases Gastrografin is not suitable as it is known to produce significant reaction in the lungs and may even prove to be fatal. Hexabrix, therefore, appears to be the safest contrast agent where leakage into the pleural space may be suspected.

The blood tumour barrier in intracranial tumours studied with X-ray computed tomography and positron emission tomography using 68-Ga-EDTA

Disruption of the blood brain barrier or rather blood tumour barrier in cerebral tumours was studied with CT after intravenous injection of contrast medium and with PET after intravenous administration of 68-Ga-EDTA. Histology from stereotactic biopsies or open surgery is compared with the radiologic findings and advantages of the respective methods are discussed. The material consisted of 47 patients mainly with supratentorial gliomas and a few miscellaneous tumours. Astrocytomas (Kernohan grade II) were found to have no disruption of blood tumour barrier while anaplastic astrocytomas and glioblastomas (Kernohan grade III and IV) had. PET is somewhat superior to CT in detection of disruption of the blood tumour barrier. It is concluded that the combination of CT and PET is of value in the assessment of intracranial tumours.

Delayed reactions to urographic contrast media

Reactions to urographic contrast media occurring after the patient had left the department were studied by giving patients a questionnaire to complete. 841 questionnaires were returned (about 80% of those issued). 70% of patients had no delayed reactions and 7% expressed a positive response to urography i.e., found the procedure interesting and not unpleasant; 13% had arm pain, 5% a rash and 14% had a variety of reactions, many of which were the same as those described in iodism. Women had significantly more rashes (7%) than men (4%) and those media containing the meglumine or iodamide ions caused more rashes than other media. Conray 420 caused more arm pain than Conray 280 or the non-ionic media, which would be expected from the known effects on vascular endothelium. Symptoms of iodism were equally common from the various contrast media.

Gastrografin aspiration in a 3 3/4-year-old girl

A case of Gastrografin aspiration in a 3 3/4-year-old child admitted for multiple trauma is described.

The use of low osmolality water soluble (LOWS) contrast media in the pediatric gastro-intestinal tract. A report of 115 examinations

There are dangers in the use of either barium sulphate suspensions or the conventional hypertonic water soluble contrast media in the gastrointestinal tract of "at risk" babies and children. These dangers can be avoided by the use of low osmolality water soluble (LOWS) contrast media. This paper reports the satisfactory use of three such contrast media, ioxaglate (Hexabrix), iohexol (Omnipaque) and iopamidol (Niopam) in 115 examinations of the gastrointestinal tracts of 89 babies and children. Morbidity from the inhalation or extravasation of contrast medium was negligible. It is proposed that LOWS contrast media should be used more widely in the gastro-intestinal investigation of all "at risk" babies and children.

Experimental evaluation of various available contrast agents for use in the gastrointestinal tract in case of suspected leakage. Effects on peritoneum

The effects of seven contrast agents were studied on the peritoneum of rats in order to find the most suitable and safe contrast agent in cases where leakage might be expected from the gastrointestinal tract into the peritoneal cavity. Hexabrix appeared to give the least tissue reaction, with Amipaque and Gastrografin in second place (but not significantly different statistically).

Experimental evaluation of various available contrast agents for use in the upper gastrointestinal tract in case of suspected leakage: effects on mediastinum

The tissue reaction of seven contrast agents--pure barium sulphate, Micropaque, Hytrast, Dionosil, Gastrografin, Amipaque and Hexabrix-was evaluated on the mediastinum of rats. This work was undertaken to define the most suitable and safe contrast agent for use in the upper gastrointestinal tract in cases where leakage outside the gut into the mediastinum, pleura or peritoneal cavity may be suspected and aspiration may be an accompanying risk. Keeping in mind the danger of aspiration, Hexabrix and Amipaque appear to be the safest contrast media for the mediastinum.

Fatal thrombo-embolic complications at aorto-femoral angiography

Fatal complications due to angiographic procedures are rare. An awareness of these complications is, however, mandatory in order to be able to prevent them. This report concerns three fatal cases with a deleterious complication of distal macro- and microembolization in connection with the angiographic procedure. In all cases the local circulation was surgically restored. The microcirculation was 'out of reach' and all three patients succumbed with profound tissue ischemia.

Experimental evaluation of various available contrast agents for use in the upper gastrointestinal tract in case of suspected leakage. Effects on lungs

The reactions of seven contrast agents--pure barium sulphate, Micropaque, Gastrografin, Dionosil, Hytrast, Amipaque and Hexabrix--on the bronchi and lungs of rats were studied. This work was undertaken to find a safe gastrointestinal contrast agent for use in post-operative patients where aspiration may be an accompanying risk. Amipaque and Hexabrix produced no significant histological reaction in the lungs and would, therefore, appear to be suitable for use in such cases.

Choice of contrast medium in sialography

Contrast media used for sialography were originally developed for other medical applications. Therefore, it was considered desirable to investigate the properties of these substances for use in sialography. Eleven radiopaque substances were selected, and their properties for sialography were studied. An in vitro study was made to determine their contrast qualities and their rate of evacuation after the sialographic examination. In animal experiments the possible harmful effects of the media on salivary gland tissues were studied. Moreover, the effects of the radiopaque material on the extraglandular tissues--which are important in understanding the consequences of spilling into these tissues--were investigated. The results of this study were compared with data from the literature. Conray 80, Amipaque 440, Lipiodol UF, Myodil, and Duroliopaque appear to be the media most suited for sialography, provided glandular overfilling is avoided. A prolonged clinical study is advised for a further selection from these agents.

The effects of metrizamide on the lung

The pathologic effects of metrizamide on the lung were studied at 24 h and 48 h after its instillation in varying concentrations selectively into the right lungs of a series of immature dogs. Iso-osmolar and slightly hyperosmolar concentrations of metrizamide were found to cause mononuclear interstitial infiltration, focal areas of pneumonia and in some cases alveolar hemorrhage. Control bacterial studies showed that the reaction was aseptic.

Thermography in the diagnosis of occlusive vascular disease of the lower limb

An assessment of the diagnostic accuracy of thermography in arterial disease of the lower limb is reported. By comparing the arteriographic and thermographic appearances of 52 patients, three independent observers had overall agreement of interpretation in approximately 50 per cent of cases. Factors found to limit accuracy were increasing subcutaneous fat thickness and localized disease with good collateral circulation.

Large-bowel perforations in patients undergoing sigmoidoscopy and barium enema

Perforation of the large bowel can occur as a complication of sigmoidoscopy, rectal or sigmoid biopsy, and even of a simple cleansing enema. If the perforation is extraperitoneal there may be no early symptoms and consequently there may be delay in diagnosis. The risk of perforation during these procedures is small but it should not be ignored. The performance of a barium enema shortly after a rectal or sigmoid biopsy may slightly increase the risk by converting a partial perforation into a complete one. Precautions can be taken to minimize the hazard.

Renal failure after radiological contrast media

Over a 12-month period four patients developed acute renal failure after undergoing radiological investigations using contrast media. Though the incidence of serious complications is low, the possibility of adverse side effects must be weighed against the usefulness of the information provided by these techniques.