Iopamidol in urography

The radiographic results obtained in urography with iopamidol, a new low osmolality contrast medium, given to 50 patients with normal renal function and 42 patients with impaired renal function, have been evaluated and compared with those obtained with ionic media of current use (meglumine sodium diatrizoate and sodium iothalamate). Based on this comparison, the authors believe there are no significant radiographic advantages to iopamidol.     

多层螺旋CT低剂量高浓度对比剂腹部血管成像应用研究

目的:探讨多层螺旋CT应用低剂量、高浓度对比剂腹部血管成像的可行性.方法:40例腹部CT血管成像(CTA)分为2组,A组:采用300 mg I/ml对比剂剂量为100 ml、生理盐水30 ml;B组:采用400 mg I/ml对比剂剂量为60 ml、生理盐水30 ml.注射流率均为4 ml/s.根据原始图像和最大强度投影(MIP)像,评价两组病例腹主动脉及其分支、肾动脉及其分支的显示程度;并测量动脉内对比剂的浓度.结果:两组病例均清晰显示腹主动脉、腹腔干、肝总动脉、脾动脉、肠系膜上动脉、肾动脉及其分支;两组动脉内的对比剂浓度虽然均维持在较高的水平,但B组明显高于A组,差异有显著性意义.肾动脉及其分支显示程度评分,B组明显优于A组,两组间存在显著性差异.结论:多层螺旋CT腹部血管成像使用低剂量、高浓度对比剂可以满足临床需要.     

合并轻度肾功能不全冠心病患者行冠状动脉介入治疗效果分析

目的探讨合并轻度。肾功能不全（MRI）的冠心病患者经皮冠状动脉介入治疗（PCI）的疗效和安全性。方法选择238例住院行PCI的患者,根据肾小球滤过率（GFR）分为MRI组102例和肾功能正常组（对照组）136例,MRI组行静脉水化治疗。记录两组基本临床特征、介入手术情况和肾功能变化等资料并作统计学分析。结果两组合并病史情况、心力衰竭比例、手术成功率、手术时间、X线曝光时间、使用对比剂类型、靶血管分布、靶病变类型、植入支架数目、住院期间和6个月主要不良心脏事件发生率相似（P〉0．05）。MRI组年龄较大（P〈0．05）,体重较轻（P〈0．05）,对比剂用量较少（P〈0．05）,使用大剂量对比剂比例较小（P〈0．05）,对比剂肾病（CIN）发生率较高（P〈0．01）,差异有统计学意义。MRI组有1例CIN患者需行血液透析,但最终所有患者肾功能均能恢复至术前水平。两组不同时间血肌酐（Scr）和GFR比较均有明显差异（P〈0．01）,但组内比较差异无统计学意义（P〉0．05）。结论通过围手术期水化治疗、减少对比剂用量等适当处理,在合并MRI的冠心病患者中行PCI效果良好,安全性高。     

Intravascular contrast media: effect of dose on renal function

Effect of contrast material dose on clinically evident change in renal function was studied prospectively in 200 examinations requiring intravenous or intraarterial administration of contrast material. All patients were adequately hydrated. Blood urea nitrogen and serum creatinine were measured before and after the procedure. Ionic and nonionic contrast agents were used. Total dose of contrast material ranged from 30 to 530 mL (mean, 237 mL). There was no tendency to give smaller doses to patients with preexisting renal impairment and no relationship between total dose and patient age. No consistent clinical effect on renal function was demonstrated with increasing dose, regardless of whether ionic or nonionic agents were used. In adequately hydrated low-risk patients with predominantly normal initial renal function and within the dose range studied, there does not appear to be any consistent clinical change in renal function with increasing contrast material dose.     

Contrast-media-induced nephrotoxicity: a consensus report

The purpose of this study was, using consensus methodology, to document current understanding of contrast media nephrotoxicity (CMN) and to identify areas where there is disagreement or confusion. To draw up guidelines for avoiding CMN based on the current understanding of the condition established by the survey. One hundred sixty-four statements were mailed to 148 members of the European Society of Urogenital Radiology (ESUR) and to 48 experts in the field of CMN. They were asked about the definition, clinical features, predisposing factors and pathophysiology of CMN and about prophylactic measures. The importance of the statements was rated on a scale from 1 to 10 (1 least important, 10 most important). Fifty-three members (38 %) and 23 experts (48 %) responded. Both groups considered that an increase in serum creatinine that peaks within 3–4 days and a decrease in creatinine clearance are the most important (rating > 7) features of CMN. Enzymuria was not considered important (rating < 6). Pre-existing renal insufficiency, diabetic nephropathy, dehydration, congestive heart failure, concurrent administration of nephrotoxic drugs and the dose and type of contrast media were considered to be risk factors. Reduction in renal perfusion and damage to tubular cells were considered the main factors in the pathophysiology of CMN (rating > 6). Hydration and the use of low osmolar contrast media were thought to minimize the incidence of CMN (rating > 6). The majority of the responders (84.6 % of members and 95.5 % of experts) believe that the incidence of CMN in patients with normal renal function is less than 5 %. Of the members, 62.5 %, and 35.3 % of experts, believe that the incidence of CMN is 20–30 % in the presence of risk factors. There was disagreement about the definition of CMN, the threshold dose of contrast media above which renal complications may develop, the safe period between repeat injections, the relevance of contrast media renal retention shown on CT and whether contrast media have long-term effects on renal function. The survey showed good understanding of CMN among those who answered the questionnaires, although areas of disagreement remain which require further research. Simple guidelines are proposed. Received: 11 February 1999; Accepted: 23 March 1999     

High dose urography: incidence and relationship to spontaneous peripelvic extravasation.

A prospective study was undertaken to determine the incidence of spontaneous extravasation of contrast in 82 patients with acute renal colic. The extravasation rate among 37 patients receiving 75 ml of contrast was 8.1%, while the rate among 45 patients receiving either 300 ml of 30% solution by infusion or a 140 ml bolus dose was 24.4%; overall the rate was 17%. Thus the incidence of extravasation was shown to increase with higher doses of contrast media. The primary dose in acute renal colic or other forms of obstructive uropathy should be in the low range (20-25 g 1-); reinjection after screening can be undertaken if necessary.     

High dose urography in patients with renal failure. A double blind investigation of iohexol and metrizoate

The new non-ionic contrast medium iohexol 350 mg I/ml was compared with the ionic contrast medium metrizoate 350 mg I/ml in a double blind, two-group urographic study performed on 20 patients with stable, impaired renal function. A dose of contrast medium of 500 mg I/kg body weight was given to each patient. Iohexol resulted in significantly fewer subjective adverse reactions than metrizoate. A similar image quality was obtained with the two contrast media. No clinically significant difference existed between the two contrast media with respect to influence on blood pressure, pulse or clinical chemical parameters. A tendency to deterioration of renal function after urography was found in both groups, but no difference of statistical significance existed between the two contrast media with respect to possible nephrotoxicity. Inadequate hydration may have been partly responsible for the nephrotoxic effect of the urographic procedure.     

Prevention of contrast media nephrotoxicity--the story so far

Contrast media nephrotoxicity (CMN) in patients with pre-existing renal impairment remains a clinically significant problem. The first step to reduce the chance of CMN is to identify patients at risk through the use of screening questionnaires and renal function measurement. Patients at risk requiring injection of contrast medium (CM) because of important clinical indications should receive a small dose of either non-ionic iso-osmolar dimeric or non-ionic low osmolar monomeric CM and hydration. Intravenous infusion (1 ml/kg body weight/h) of 0.9% saline starting 4 h before CM injection and continuing for at least 12 h afterwards is effective in reducing the incidence of CMN. Prophylactic haemodialysis does not lower the risk of this complication. The value of pharmacological manipulation with renal vasodilators (calcium channel blockers, dopamine, atrial natriuretic peptide, fenoldopam (selective dopamine-1 receptor agonist), prostaglandin E(1), non-selective adenosine receptors antagonist (theophylline), non-selective endothelin receptor antagonist or the antioxidant acetylcysteine has not been fully proven. However, haemofiltration for several hours before and after contrast medium injection offers good protection against CMN in patients with advanced renal disease.     

Contrast agent nephrotoxicity: comparison of ionic and nonionic contrast agents

The effects on glomerular and proximal tubular function of an ionic contrast agent (sodium meglumine diatrizoate) and a nonionic agent (iopamidol) were compared in 34 patients with normal renal function. The patients received large doses (2.5 ml/kg body weight) of contrast material for IV digital subtraction angiography. Urine samples, collected before, immediately after, and on the first and third days after digital subtraction angiography, were analyzed for albumin, alanil-aminopeptidase, alpha-glucosidase, and beta-2-microglobulin. The changes noted were mild and of short duration with both contrast agents, despite the high dose given. These results suggest that, at least as far as renal toxicity is measured by these tests is concerned, ionic monomers can be safely used instead of more expensive nonionic media in procedures, such as digital subtraction angiography, that require high doses of contrast material.     

Urinary protein excretion following intravenously administered ionic and non-ionic contrast media in man

Urinary protein excretion following intravenous administration of the radiographic contrast media (CM) diatrizoate (ionic) and iopromide (non-ionic) was examined in 20 patients with normal renal function. Neither of the two CM had any effect on the 24-h urinary excretion of albumin (a marker of glomerular proteinuria). The 24-h urinary excretion of the retinol-binding protein (a marker of low molecular weight or tubular proteinuria) and the folate binding protein, a protein localized in the brush-border membranes of the proximal tubular cells, showed a statistically significant transient increase the day after diatrizoate injection, whereas no increase was observed after iopromide. Thus, only a minimal and temporary disturbance of the renal proximal tubular function was observed after diatrizoate injection in patients with normal renal function.     

Weight-adapted iodinated contrast media administration in abdomino-pelvic CT: Can image quality be maintained?

IntroductionIn many centres, a fixed method of contrast-media administration is used for CT regardless of patient body habitus. The aim of this trial was to assess contrast enhancement of the aorta, portal vein, liver and spleen during abdomino-pelvic CT imaging using a weight-adapted contrast media protocol compared to the current fixed dose method.MethodsThirty-nine oncology patients, who had previously undergone CT abdomino-pelvic imaging at the institution using a fixed contrast media dose, were prospectively imaged using a weight-adapted contrast media dose (1.4 ml/kg). The two sets of images were assessed for contrast enhancement levels (HU) at locations in the liver, aorta, portal vein and spleen during portal-venous enhancement phase. The t-test was used to compare the difference in results using a non-inferiority margin of 10 HU.ResultsWhen the contrast dose was tailored to patient weight, contrast enhancement levels were shown to be non-inferior to the fixed dose method (liver p < 0.001; portal vein p = 0.003; aorta p = 0.001; spleen p = 0.001). As a group, patients received a total contrast dose reduction of 165 ml using the weight-adapted method compared to the fixed dose method, with a mean cost per patient of £6.81 and £7.19 respectively.ConclusionUsing a weight-adapted method of contrast media administration was shown to be non-inferior to a fixed dose method of contrast media administration. Patients weighing 76 kg, or less, received a lower contrast dose which may have associated cost savings. A weight-adapted contrast media protocol should be implemented for portal-venous phase abdomino-pelvic CT for oncology patients with adequate renal function (>70 ml/min/1.73 m²).     

Renal scans in pregnant transplant patients

This study demonstrates the normal technetium-99m diethylenetriaminepentaacetic acid ([99mTc]DTPA) renal scan in pregnant patients with transplanted kidneys. Five pregnant renal transplant patients had seven [99mTc]DTPA renal studies to assess allograft perfusion and function. All scans showed the uteroplacental complex. The bladder was always compressed and distorted. The transplanted kidney was frequently rotated to a more vertical position. In all patients allograft flow and function were maintained. There was calyceal retention on all studies and ureteral retention activity in three of five patients. Using the MIRD formalism, the total radiation absorbed dose to the fetus was calculated to be 271 mrad. This radiation exposure is well within NRCP limits for the fetus of radiation workers and an acceptable low risk in the management of these high risk obstetric patients.     

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.     

Single-dose captopril scintigraphy in the diagnosis of renovascular hypertension

Renal scintigraphy with [99mTc]diethylenetriaminepentaacetic acid (DTPA) and/or sodium-iodine-131-o-iodohippurate (HIP) was performed before and after an oral dose of captopril (50 mg) in 18 patients with renovascular hypertension (RVH) due to renal artery stenosis (RAS) and 18 controls. In every patient with RVH, captopril induced, enhanced or sustained abnormal findings on HIP scintigraphy depending on the degree of RAS. With DTPA scintigraphy, renal function decreased after captopril in ten kidneys with RVH-related RAS and adequate baseline renal function, but this phenomenon was not evident in 11 kidneys with RVH and poor renal function. Captopril did not influence HIP or DTPA studies of kidneys with patent renal arteries (patients after successful renal angioplasty, patients with essential hypertension, contralateral kidneys of patients with unilateral RVH) or ipsilateral kidneys with mild and subcritical (less than 60%) RAS in patients without hypertension and/or normal renal vein renin activity. When HIP and DTPA scintigraphy were compared in the same patients, HIP demonstrated greater sensitivity and specificity than DTPA, particularly in patients with poor renal function. HIP scintigraphy before and after a single dose of captopril may provide a rapid sensitive and minimally invasive test for screening patients with hypertension.     

Contrast agent nephrotoxicity. An appraisal

Impairment of renal function occasionally occurs following the administration of intravascular contrast agents. As a consequence even intravenous urography in the investigation of renal failure was until 20 years ago generally considered to be contraindicated. In the United Kingdom in recent years this extreme view has been rejected and high dose intravenous urography is frequently performed on patients in renal failure. Contrast agent nephrotoxicity has not been frequently encountered. Experience in the United States, however, has been different, a worryingly frequent impairment of renal function after contrast administration being reported by several authors. The reason for this different experience is unclear but it may be the result of patient selection and preparation or contrast dose regime. The United States studies indicate that the patients most at risk are those with already impaired renal function, diabetics and the elderly. A brief review of the literature is given and a classification of possible mechanisms of nephrotoxicity is proposed. It is argued that on the basis of any or all of these mechanisms the low osmolality contrast agents would be expected to be less nephrotoxic than the conventional agents. This suggests that their use should be considered in those patients defined as high risk.     

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.     

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.     

Low dose intravenous urography: results and technique modifications

100 consecutive patients routinely referred for intravenous urography were examined using low doses of the low osmolar contrast medium Iohexol (Omnipaque 350mgl/ml). Their dosage schedule was based on the physiological parameters of age, sex, body weight and renal function. Comparison with a control group using standard contrast doses revealed a 42% reduction in contrast could be used, and still produce diagnostic studies. Nephrographic quality was reduced in the low dose group requiring technique modification, in particular a delayed film sequence. Further reductions in contrast use are envisaged in patients over the age of 40 years.     

Renal vein ethanol concentration during ablation of renal cell carcinoma

Absolute ethanol is an effective embolizing material for the ablation of renal cell carcinoma with a balloon catheter. We have measured the renal vein ethanol concentration during embolization in 9 patients in order to determine whether toxic levels are achieved. Total occlusion of the embolized arteries was obtained using an average of 12.9 ml (range 8–18) ethanol. Renal vein ethanol concentration varied from trace amounts to 0.79%. There was a significant correlation of the maximum renal vein concentration with the ethanol dose per tumor size. The authors conclude that the renal vein ethanol concentration remains sufficiently low to be harmless when a proper balloon occlusion is used. The optimum ethanol dose may be a function of tumor size.     

静脉注射对比剂钆喷替酸葡甲胺对肾功能正常及轻、中度异常者近期血清肌酐值的影响

目的 探讨静脉注射对比剂Gd-DTPA对常规MR增强扫描人群肾功能的影响.方法 连续收集门诊住院病例623例,均注射Gd-DTPA行MR增强扫描检查的病例进行研究,检测患者增强扫描前2周内的基础血清肌酐值以及增强扫描后24～72 h内的血清肌酐值,并计算其肾小球滤过率估算值(eGFR)进行分组及统计分析.根据注射对比剂剂量将患者分为常规剂量组和双倍剂量组,各组根据注射前eGFR值再各分为肾功能正常、轻度异常及中度异常组.对各组注射前后血清肌酐值的比较均使用配对样本的t检验,eGFR均值的比较均使用成组配对样本秩和检验.结果 无患者出现严重不良反应及严重肾功能衰竭.注射对比剂后,总体血清肌酐值从(74.0±17.2)μmol/L降至(71.5±19.0)μmoL/L(t=5.39,P＜0.05);除双倍剂量下肾功能轻度组的血清肌酐值从(89.6±12.2)μmoL/L升至(92.1±14.6)μmol/L(t=0.68,P＞0.05),肾功能中度异常组从(118.3±15.3)μmol/L升至(135.7±8.5)μmol/L(t=2.02,P＜0.05)之外,肾功能正常组以及常规剂量下各组的血清肌酐值均降低.结论 Gd-DTPA在常规剂量下经静脉注射对肾功能正常及轻、中度异常者的近期血清肌酐值影响不大,是一种比较安全的MR对比剂.但对于肾功能异常者行双倍剂量注射时需密切观察并随访.