Post-operative haemorrhagic complications following the ingestion of aspirin have been reported after several types of surgery, most notably coronary artery bypass surgery. In this study, aspirin ingestion also appeared to be a significant aetiological factor in post-prostatectomy haemorrhage. This is explained in terms of its inhibitory effect on platelet aggregation. A history of aspirin ingestion should be carefully sought and its haemorrhagic implications considered prior to prostatectomy.

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Objective To determine the safety of the conservative management of ureteric calculi of >4 mm in diameter, using mercapto-acetyltriglycine (MAG3) radioisotope renography to monitor renal parenchymal function. Patients and methods Patients with symptomatic unilateral ureteric calculi were recruited prospectively. After con®rming the position of the stone using contrast urography, a MAG3 radioisotope renogram was taken within 48 h of admission and again 1 month after the patients became stone-free. The indications for intervention were ipsilateral loss of function (o5% loss), infection, pain or any combination of these factors. The recovery of function was determined by follow-up renography. Results In all, 54 patients were recruited; 18 were initially allocated to conservative treatment although four later required intervention for pain. The remainder required early intervention for pain (eight), diminished function only (15) or diminished function with infection (13). Of the 54 patients, 28% had silent' loss of renal function at presentation. No calculi of >7 mm diameter passed without intervention. The mode of initial management was determined according to individual clinical need. The upper tracts of all patients were relieved of obstruction and all patients were rendered stone-free. Intervention for reduced function only (at ¡7 days) gave a signi®-cantly better (P=0.03) recovery of function than those undergoing later intervention. The combination of reduced function and infection were unrelated to outcome after intervention. Conclusions The conservative management of stones of 5±7 mm diameter is safe, providing that radioisotope renography is used to identify those renal units requiring intervention. This approach allows timely intervention to maximize the recovery of renal function.

As iodinated contrast medium is cleared by glomerular filtration, it should be possible to apply the same principles utilized in radionuclide studies to derive differential renal function by comparison of enhancing renal volumes derived from contrast enhanced multidetector CT (CEMDCT). Having established a technique iteratively which appeared successful, a retrospective study was performed using 25 consecutive patients with a wide range of urological conditions who had undergone both CEMDCT, including the renal area in the portal venous phase, and nuclear medicine (NM) assessment of renal function with no urological intervention between the studies. Proprietary volume software was used to quantify the volume and attenuation of each kidney, the products of which (after subtraction of soft tissue attenuation derived from a region of interest over psoas) gave right and left enhancing renal volumes. The contribution by each kidney as a percentage of total renal enhancing tissue was derived. Comparison with NM studies resulted in excellent correlation of relative renal function by CEMDCT and NM assessments having a regression of near unity and a Pearson's correlation coefficient of 0.96. Bland Altman and Passing Bablock tests confirmed good agreement between the two methods with no bias. This is a simple, practicable processing technique using standard portal venous phase CEMDCT images to quantify differential function. This technique may allow a one-stop CT assessment of both anatomy and function.

Objective To review experience in the management of the obstructed ureter using antegrade stenting in a variety of conditions. Patients and methods Between 1984 and 1993, 41 patients (mean age 57 years, range 9–83) had antegrade stents placed by an experienced interventional radiologist. The causes of obstruction were urological in 27, gynaecological in eight, colorectal in three and miscellaneous in three. Results The overall success rate for antegrade stent insertion was 83% and the failure rate was greatest (four of six) in cases of ureteric injury following gynaecological procedures. There were no immediate complications. Conclusion Antegrade stenting can be used as a temporary or permanent solution to ureteric obstruction. The technique is safe, acceptable to patients and avoids the need for a general anaesthetic.