Technetium-99m-labelled red blood cell scintigraphy was used in the investigation of 41 patients with major rectal haemorrhage. Red cells were labelled in vivo with technetium-99m pertechnetate and serial scans (0-36 h) were taken using a large field gamma camera. Twenty-two men and 15 women, mean age 71.3 years (range 32-91 years), and four children were studied. Forty-three scans were performed in all and there were 31 positive and 12 negative results. In each case the accuracy of the scan in localizing the bleeding site was checked either by independent investigations or at laparotomy. A definite bleeding site was identified in 30 cases and red cell scintigraphy correctly localized 29 of these (sensitivity 97 per cent). In the remaining 13 cases a bleeding site was not identified by any of the independent investigations and in this group there were two false positive scans (specificity 85 per cent). The investigation had a high predictive value when both positive (94 per cent) and negative (92 per cent). These data suggest that technetium-99m-labelled red cell scintigraphy should be used more widely in the investigation of patients with suspected lower gastrointestinal haemorrhage.

In normal healthy subjects radiographic contrast media are cleared by the kidneys with a half-life of approximately 2 h and a total body clearance of 8 l/h. The mechanism of contrast clearance has not been previously investigated in chronic renal failure patients undergoing continuous ambulatory peritoneal dialysis (CAPD). A study was undertaken to investigate the pharmacokinetics of a non-ionic water soluble radiographic contrast medium (iopamidol) in 10 patients stabilized on CAPD. All patients (eight male, two female) aged 22-68 years (median 53 years) had injection of 30 ml of iopamidol 300 via a forearm vein to investigate subclavian vein patency following previous cannulation for haemodialysis. Venous blood samples, CAPD dialysate and urine were collected for seven days post injection. The mean plasma half-life was 37.9 h (SD 10.6) (range 24.1-57.2 h) for the CAPD patients and was greatly prolonged in comparison to healthy subjects. The total body clearance of iopamidol was also greatly reduced (0.377 l/h). CAPD removed an average of 53.6% of the administered dose (range 36.3-80.8%) whilst an average of 26.9% was excreted in the urine (range 1.3-56.3%). The combined renal and dialysate clearance was up to 93% of the administered dose over the period of the study. There is therefore some evidence for a small extra renal clearance of iopamidol in end-stage renal failure patients. This study has shown for the first time that patients with end-stage renal failure undergoing CAPD have significantly delayed elimination of contrast medium. This should be taken into consideration when extensive or prolonged investigations using contrast medium are proposed.

The value of dynamic CT scanning for staging renal carcinoma was studied prospectively in 28 patients and the results compared with those of ultrasonography, arteriography and conventional CT. Arteriography correctly staged 48% of tumours; ultrasonography and conventional CT correctly staged 50% and dynamic CT correctly staged 72%. Dynamic CT staged renal carcinoma more accurately than ultrasonography, conventional CT or arteriography and it is suggested that arteriography should be restricted to specific indications such as the mapping of arterial anatomy and therapeutic renal artery embolisation.

The value of routine scrotal ultrasonography has been evaluated in a prospective study of 109 men with scrotal symptoms or signs. Ultrasonography had a sensitivity of 100% and specificity of 99% for testicular tumour. Clinically useful information was provided in 53% of patients and 8% might have avoided surgery if the ultrasound report had been heeded. Ultrasonography did not provide any additional information in patients with scrotal pain and an entirely normal scrotum clinically, and in those with epididymal cysts in whom the testis was palpably normal. If these 2 groups had been excluded from routine scrotal ultrasonography there would have been a 25% reduction in the number of examinations without any reduction in diagnostic yield.

IADSA could not determine when reconstruction was not possible, but in those deemed reconstructable by IADSA, the surgeon can confidently expose the appropriate artery at the appropriate level knowing the pedal run-off status in 86% of patients. IADSA should not be used to exclude reconstruction (i.e. pre-reconstruction IOA is still required in these patients) but for the remainder, IADSA can be used to plan surgical strategy without recourse to IOA.