Intravenous urography with low-osmolality contrast agents: theoretical considerations and clinical findings

Iopentol in Urography

A double-blind comparative study of the nonionic contrast medium iopentol and the ionic contrast medium metrizoate for urography was carried out in 200 adult outpatients. Significantly less discomfort and other side effects were observed following iopentol than following metrizoate. No serious adverse reactions and no clinically significant alterations in heart rate or blood pressure were observed. A questionnaire was used to record delayed symptoms, from 30 min after contrast medium injection and for one week. The response rate was 92% and delayed adverse events were reported by 45%. The incidence of delayed reactions was significantly lower following iopentol than following metrizoate, i.e., delayed arm pain, fatigue, headache, diarrhea, nasal congestion, and rash. Delayed arm pain was probably due to contrast medium induced thrombosis in 1% following iopentol and in 8% following metrizoate. Most other symptoms were probably related to a combination of nocebo effect and coincidentally occurring symptoms. The urograms with both media were of similar high quality. Iopentol was found a suitable contrast medium for urography.

Hydralazine predisposes to acute cutaneous vasculitis following urography with iopamidol

We report a 60-year-old woman with renovascular hypertension who developed a severe cutaneous vasculitis 24 h after the injection of iopamidol during urography. A review of the literature suggests that her concomitant hydralazine therapy probably predisposed her to this reaction, as similar reactions have occurred in systemic lupus erythematosus, and hydralazine can induce a LE-like syndrome. We recommend that urography should be avoided in patients receiving hydralazine.

Plasma osmolality, iodine concentration and urographic images following high and low osmolar contrast media

Three contrast media (sodium iothalamate, iopamidol and sodium/methylglucamine ioxaglate) in a dose of 240 mg iodine per kilogram of body weight were compared in clinical urography. The ionic monomer sodium iothalamate was the only medium to significantly elevate the plasma osmolality though it returned to normal values within 4 min. All three media exhibited first order linear kinetics. When corrected for the effects of diuresis, sodium iothalamate was shown to give the highest urinary iodine concentrations. On visual scoring sodium iothalamate produced better nephrograms and overall urograms than either of the low osmolar agents.

Unequal doses of ioversol versus diatrizoate for urography

A randomized, double-blind clinical trial was performed to compare a higher dose of conventional ionic contrast media (diatrizoate) with a lower dose of a new, nonionic contrast material (ioversol) for excretory urography (EU). One hundred twenty patients were randomized to receive either 100 ml of diatrizoate (Renografin-60) or 75 ml of ioversol (Optiray-320). Despite the lower iodine dose, the use of ioversol resulted in significantly better opacification of the calyces, renal pelves, and ureters. There was no significant difference in renal parenchymal opacification, opacification of the urinary bladder, or distention of the collecting system. We conclude that high-quality EU can be performed with a lower iodine dose using ioversol.

A double-blind comparison of iopromide and iopamidol in intravenous urography

A randomised double-blind comparative study was performed to assess the imaging properties and side-effects of two non-ionic contrast media, iopromide and iopamidol, in intravenous urography in high risk patients. The results showed the two contrast media to be similar in their imaging efficacy and incidence of side-effects. Using 50 or 100 ml of iopromide or iopamidol (370 mgI/ml), the quality of nephrograms was found to be dose dependent but the quality of pyelograms was not dose dependent.

Intravenous urography with a new non-ionic contrast media in a clinical phase III study: iopentol vs iohexol

The safety and diagnostic efficacy of iopentol 300 mg I/ml were compared with iohexol 300 mg I/ml in 300 patients submitted for urography. The study was carried out as a double-blind, randomised parallel study where 149 patients received iopentol and 150 patients iohexol. There were no significant differences between the patients receiving the two contrast media with regard to demographic parameters, rate of injection or total dose of injected contrast media. No changes in blood pressure and no clinically important changes in heart rate were detected in the two groups. No serious adverse effects occurred. Seven patients (5%) in the iohexol and 12 patients (8%) in the iopentol group experienced adverse effects other than a sensation of warmth. Fourteen iohexol patients (9%) and 18 iopentol patients (12%) experienced warmth related to the contrast injection. Excellent films were obtained in most patients and no difference in diagnostic quality between iopentol and iohexol was observed.

A comparison of different doses of non-ionic contrast media in i.v. urography

This study attempts to find out what is the appropriate dose of non-ionic contrast media to provide an acceptable study at the lowest possible cost. 139 adults with normal renal function were studied. Four different dose regimes were employed and a standardised set of I.V.U. films were obtained. These were reviewed by two independent assessors who were unaware of the dose regime used. Each I.V.U. was scored on a modified Fry regime. This survey showed a clear relationship between quality and dosage.

Comparison of the image quality of intravenous urograms using low-osmolar contrast media

Almost equivalent, intravenous iodine doses of the three new low-osmolar contrast media, ioxaglate (Hexabrix), iopamidol (Niopam) and iohexol (Omnipaque) have been compared for image quality on the intravenous urogram. Generally good radiographic images were obtained. Iohexol gave better results for the nephrogram and pelvicalyceal distension compared with the other contrast media, but only the nephrogram results were statistically significant. Pyelographic density and ureteric distension and density were similar with all three contrast media. In patients where low-osmolality contrast media need to be used for intravenous urography, we suggest that iohexol gives the best radiographic images. Other factors, such as cost and the relative incidence of side-effects of the low-osmolar contrast media also need to be taken into consideration.

Quality of urograms in infants: a comparison of sodium diatrizoate, metrizamide and iohexol

A consecutive series of 314 intravenous urograms performed in infants were reviewed and assessed for quality. The first 106 examinations were performed using sodium diatrizoate (Hypaque 270) as the contrast medium, the next 98 patients received metrizamide (Amipaque 280) and the final 110 received iohexol (Omnipaque 300). Thirty-five patients had to be excluded from the study for a variety of reasons, after which there were totals of 98 in the diatrizoate, 90 in the metrizamide and 91 in the iohexol groups. Assessing quality in terms of nephrographic and pyelographic density, sodium diatrizoate was found to be better than the non-ionic agents. Although the differences reached statistical significance they are small and unlikely to affect the information obtained in clinical practice. There was no difference in overall quality between metrizamide and iohexol. Comparing the degree of pyelographic distension and ureteric visualization using the three agents, no difference was found between the groups.

Fatal Stevens-Johnson syndrome following urography with iopamidol in systemic lupus erythematosus

A 46 year old white woman with active systemic lupus erythematosus developed a skin rash 8 hours after intravenous urography with the non-ionic contrast medium iopamidol. Severe Stevens-Johnson syndrome with erythema multiforme, intrahepatic cholestasis, pulmonary infiltrates and acute renal failure ensued, leading to her death. Although non-ionic contrast media are generally less toxic than traditional ionic agents, their use in patients with immunological disease may be hazardous.

Low dose low osmolar intravenous urography

A prospective double blind randomised trial using 25 ml of Hexabrix 320 (ioxaglate, May and Baker), Niopam 370 (iopamidol, Merck) or Omnipaque 350 (iohexol, Nycomed) intravenous urography was carried out. The results showed no perceptible difference in the diagnostic quality of urograms with each of the media. An additional 25 ml of contrast medium was required by 4% of patients in order to obtain a satisfactory examination. We recommend that a dose of 25 ml of low-osmolar medium be used for all patients with the exception of the obese, those taking diuretics or those who have renal impairment.

Three-dimensional computed tomographic reformations of sellar and para-sellar lesions

The purpose of this study was to determine whether diagnostically useful three-dimensional (3D) reformations could be obtained from unmodified high resolution pituitary CT scans. Twelve CT examinations in 9 patients in whom an enhancing tumour or extensive bone destruction was identified around the sella, were studied using 3D images obtained on soft tissue and bone thresholds. 3D images were considered superior to conventional CT sections and reformations for the assessment of the vascular relations of tumours with large supra-sellar components, and in cases of extensive bone erosion. In selected cases, 3D CT imaging may facilitate a faster and more comprehensive appraisal of high resolution CT studies by clarifying otherwise complex spatial relationships.

High- and low-osmolar contrast agents in urography: a comparison of the appearances with respect to pyelotubular opacification and renal length

The incidence of pyelotubular opacification and the change in renal length during intravenous urography with iohexol (Omnipaque) was compared with sodium/meglumine diatrizoate (Urografin). Pyelotubular opacification was seen in 14 out of 29 urograms performed with iohexol compared with one out of 28 urograms performed with sodium/meglumine diatrizoate. This increased incidence is statistically significant and has not been previously documented. The increase in renal length following intravenous contrast medium was similar for both iohexol and sodium/meglumine diatrizoate. The significance of these findings with respect to the interpretation of urograms performed with iohexol is discussed.