非离子型大剂量静脉尿路造影

静脉尿路造影常规的方法是将有机碘肾脏排泄的离子型造影剂(复方泛影葡胺)注入肘静脉，并通过压迫输尿管，经肾脏排泄后，在不同时间内使造影剂逐渐增多变浓的充盈。在肾盂、肾盏内，使肾盂肾盏显示影像，但目前随着医学技术的发展，临床的需要，人民经济水平的不断提高，我们有选择性地采用头低足高，大剂量不加压，非离子型的静脉尿路造影法。     

The effect of nonionic radiographic contrast medium on serum electrolytes and proteins during intravenous urography

A prospective study was done on 20 adult patients to determine changes in the serum electrolytes and proteins produced by bolus administration of 100 ml of the nonionic contrast medium iohexol (Omnipaque 300) for intravenous urography. Blood samples were taken for analysis before injection and at five and 30 minutes after. Statistically significant decreases in serum sodium, potassium, total protein, albumin, calcium, and phosphate were noted at five minutes post-injection (p less than 0.001). The mean percentage decreases were sodium 2.4%, potassium 5.1%, total protein 13.7%, albumin 14.2%, calcium 8.6%, and phosphate 5.3%. These values were significantly decreased after 30 minutes (p less than 0.001) except for the serum potassium concentration which had almost returned to baseline level. The changes in sodium, potassium, and phosphate are small and thought to be secondary to hemodilution due to the osmolality of the contrast. The changes in total protein, albumin, and calcium were much greater and difficult to explain. Although we found significant changes in serum biochemistry and proteins, these did not appear to cause clinical abnormalities in this group of patients.     

Asymptomatic blood pressure and pulse rate changes during intravenous urography. Ionic contrast media vs. nonionic contrast media

In 8,232 examinations of intravenous urography (4,832 examinations with ionic contrast media and 3,400 examinations with nonionic contrast media), systemic blood pressure and pulse rate were continuously monitored by an automatic blood pressure and pulse rate monitoring device before and after injection of contrast media. The intravenous injection of ionic contrast media caused mild to moderate hypotensive reactions (20%-39% decrease of systemic blood pressure) in 7 examinations (0.14%) and severe hypotensive reactions (greater than 40% decrease of systemic blood pressure) in 12 examinations (0.25%). There were no clinical symptoms other than hypotensive reactions in 8 of the 19 examinations (42.1%). On the other hand, the intravenous injection of nonionic contrast media did not cause severe hypotensive reactions but mild hypotensive reactions (20%-29% decrease of systemic blood pressure) in 3 examinations (0.09%). These 3 examinations did not have clinical symptoms other than hypotensive reactions. Of the 19 examinations using ionic contrast media, the hypotensive reactions with significant change of pulse rate (greater than 20%) was associated with increase of pulse rate in 17 examinations and decrease of pulse rate in 2 examinations. On the other hand, the hypotensive reactions had an association with a significant increase (greater than 20%) of the pulse rate in only one of the 3 examinations using nonionic contrast media. The pulse rate was unchanged after injection of contrast media in the remaining 2 examinations although there was mild hypotension. In conclusion, nonionic contrast media caused fewer and less severe changes in blood pressure and pulse rate without obvious clinical symptoms compared with ionic contrast media.     

Quality of urography and renal clearance of ionic and nonionic contrast media.

The authors evaluated whether urographic quality correlated with patient hydration and the level of their renal function, depending on whether they received ionic or nonionic contrast media. One hundred patients with normal serum creatinine levels were randomly assigned to receive intravenous urography with either an ionic high-osmolar or a nonionic low-osmolar contrast medium. Patient hydration was evaluated by measuring urine osmolality in a sample voided just before the examination. The plasma concentration of iodine was determined in a single blood sample drawn approximately 3 hours later. From these determinations the plasma clearance of contrast medium was calculated. The urograms were assessed blindly with regard to nephrographic and pyelographic opacification, as well as overall diagnostic quality. The clearance varied between 42 and 115 mL x minutes-1 x 1.73 m-2. No systematic correlation of practical significance was found between the clearances and the urogram quality. A high urinary osmolality before the examination tended to improve quality with both media. It is not possible to assess glomerular filtration rate from nephrographic and pyelographic opacification, or from overall quality of routine urograms in patients with normal serum creatinine levels.     

Glomerular filtration rate estimated after multiple injections of contrast medium during angiography

In twenty-six patients referred for angiography, clearance of contrast medium was determined with x-ray fluorescence analysis after multiple injections of contrast medium. A formula for correction of the injected amount, which takes into consideration the different times of contrast medium injections, approximating the total injected amount into one injection, was used. A single injection clearance of 51Cr-EDTA was determined at the same time. The results showed a good correlation between the clearance of contrast medium after multiple injections and the 51Cr-EDTA clearance after a single injection (r = 0.945). The correlation between contrast medium clearance calculated without correction for the different injection times, and 51Cr-EDTA clearance was the same (r = 0.946), due to short angiography time and rather low clearance values in our patients. It is concluded that total plasma clearance of contrast medium can easily be estimated after multiple injections. In this way patients with a risk of developing post-angiographic renal failure can be found.     

Estimating kidney function during urography. Comparison of contrast medium clearance and simultaneous 51Cr-EDTA clearance

Blood samples were taken from 21 subjects at 2 to 4 hours after simultaneous injection of contrast medium (metrizoate) for urography and 51Cr-EDTA. Clearance calculations were performed using the single injection (single slope) technique. The plasma concentrations of 51Cr-EDTA and contrast medium were measured by gamma counting and X-ray fluorescence analysis, respectively. A good correlation was found between the clearance of 51Cr-EDTA and clearance of contrast medium (r = 0.94).     

Determination of single-kidney glomerular filtration rate (GFR) with CT urography versus renal dynamic imaging Gates method

Objectives

To present a single-kidney CT-GFR measurement and compare it with the renal dynamic imaging Gates-GFR.

Materials and methods

Thirty-six patients with hydronephrosis referred for CT urography and 99mTc-DTPA renal dynamic imaging were prospectively included. Informed consent was obtained from all patients. The CT urography protocol included non-contrast, nephrographic, and excretory phase imaging. The total CT-GFR was calculated by dividing the CT number increments of the total urinary system between the nephrographic and excretory phase by the products of iodine concentration in the aorta and the elapsed time, then multiplied by (1- Haematocrit). The total CT-GFR was then split into single-kidney CT-GFR by a left and right kidney proportionality factor. The results were compared with single-kidney Gates-GFR by using paired t-test, correlation analysis, and Bland-Altman plots.

Results

Paired difference between single-kidney CT-GFR (45.02 ± 13.91) and single-kidney Gates-GFR (51.21 ± 14.76) was 6.19 ± 5.63 ml/min, p<0.001, demonstrating 12.1% systematic underestimation with ±11.03 ml/min (±21.5%) measurement deviation. A good correlation was revealed between both measurements (r=0.87, p<0.001).

Conclusion

The proposed single-kidney CT-GFR correlates and agrees well with the reference standard despite a systematic underestimation, therefore it could be a one-stop-shop for evaluating urinary tract morphology and split renal function.

Key points

? A new CT method can assess split renal function ? Only using images from CT urography and the value of haematocrit ? A one-stop-shop CT technique without additional radiation dose

     

Determination of glomerular filtration rate with Visipaque in patients with severely reduced renal function

Iodixanol (Visipaque, Nycomed Imaging AS, Oslo, Norway), an isotomic, dimeric and non-ionic contrast medium (CM), and iohexol (Omnipaque, Nycomed Imaging AS, Oslo, Norway), a low-osmolar, monomeric and non-ionic contrast medium, were used as glomerular filtration rate (GFR) markers in patients with severely impaired renal function. Different methods for determining GFR were compared. A total of 16 patients with s-creatinine > 400 mol/l were enrolled in the study; 8 in each CM group. Serum-iodine was measured, and plasma CM clearance was determined using the Bröchner-Mortensen method, the single-sample method and conventional method. The ratios between the results obtained from the conventional method and each of the two other methods were calculated. These data were plotted against the mean of the pairs compared, and the upper and lower limits of agreement were calculated as the mean ratio ± 2SD. The comparison showed a high degree of agreement between methods, and the two simpler methods seem to be good alternatives to the conventional method, which gave good estimates of GFR (vs that determined by means of renal ¹²⁵I-iothalamate clearance) when 24-h blood samples were included. However, slight overestimations of GFR, due to extrarenal excretion of the CM, were observed. In summary, serum clearance of iodixanol, as determined by the Bröchner-Mortensen method or single-sample method seems to be a simple and accurate marker of GFR in patients with severely reduced renal function. The findings obtained with iodixanol were similar to those obtained with iohexol.Correspondence to: P. Kjærsgaard     

Changes in serum magnesium during excretory urography. A comparison of ionic and nonionic contrast media.

RATIONALE AND OBJECTIVES. It is known that ionic contrast media (CM) bind magnesium and that patients with asthma often benefit from magnesium injections. Similarly, asthmatics have a higher incidence of CM reactions. This work tests the hypothesis that ionic CM alter serum magnesium more than nonionic CM. METHODS. Ten patients were divided into two groups; one group received iothalamate and the other received iohexol. RESULTS AND CONCLUSIONS. The total magnesium level changed significantly from baseline in the iothalamate-treated group (P less than .01). Iothalamate produced a significant decrease in protein-bound magnesium (P less than .01) with a significant increase in filterable magnesium (P less than .01). Iohexol did not produce significant changes for any of the magnesium fractions. The patient with the most clinically significant adverse reaction (though minor) had the lowest baseline magnesium level. Further studies with larger groups including patients with asthma are needed.     

The technetium-99m-DTPA renal uptake-plasma volume product: a quantitative estimation of glomerular filtration rate.

An image-based method for estimating quantitative renal glomerular filtration rates (GFR) by calculating the product of the renal uptake rate and plasma volume is presented. By using the relationship GFR = F.PV/t, F represents renal 99mTc-DTPA uptake after bolus injection, PV is the plasma volume and t is time. This GFR evaluation was carried out on 96 patients and compared to GFR values determined in the same patients using radiotracer blood clearance techniques relying on two venous blood samples. When estimating patient plasma volumes using patient's weight and measured hematocrit values, the image-based method for calculating GFR accurately approximates the values obtained from blood samples (linear regression slope = 1.03; y-intercept = -2.81 ml/min). The two techniques correlate with a value of r = 0.89.     

Ioxilan, a third generation low osmolality nonionic contrast medium. Systemic and renal hemodynamic effects

The choice between high cost, low toxicity nonionic contrast media (CM) and low cost ionic CM poses a dilemma for radiologists. Ioxilan, a third generation nonionic CM, is obtained by simple conversion from an ionic CM. To examine how this economically promising, low osmolality CM (570 mOsm at 300 mgI/ml) affects canine systemic and renal hemodynamics, IV bolus injections of 350 mgI/ml at 2 ml/kg of Iohexol and Ioxilan were compared. Satisfactory nephrograms and pyelograms were produced by both agents, without significant differences. The effects on systemic and renal hemodynamics were minimal and statistically equal for both CM. The acute systemic and renal responses and radiographic image quality of Ioxilan and Iohexol confirm that the two compounds are biologically equivalent, and that the novel molecular design employed in Ioxilan to achieve very low osmolality also provides good biological tolerance.     

Simulation of renal function by tumor and its effect on the calculated glomerular filtration rate

A patient with a retroperitoneal sarcoma near the left kidney was to undergo radiotherapy. Renal assessment with Tc-99m DTPA to determine renal function before radiotherapy resulted in what was thought to be a low glomerular filtration rate based on the Gates computer method and the Russell two-blood-sample method. Most likely this resulted from the observed significant accumulation of DTPA in the tumor for the first few minutes with washout for the rest of the imaging time, simulating renal function.     

Preclinical evaluation of iotrolan as a contrast medium for angiography and urography]

Efficacy and tolerability of iotrolan, a nonionic isotonic dimer, as a contrast medium for angiography and urography were investigated in animals. In the arteriography of rabbit femur, the efficacy of iotrolan 280 mgI/ml was as good as iopamidol 300 mgI/ml and better than meglumine diatrizoate 306 mgI/ml. In rat urography, the efficacy of iotrolan 280 mgI/ml was better than both iopamidol 370 mgI/ml and iohexol 350 mgI/ml. Vascular pain was less with iotrolan 280 mgI/ml than with iohexol 300 mgI/ml in rats. Effect of iotrolan on the pulmo-cardiovascular parameters, arterial pO2, hematocrit and plasma osmolality was less than iopamidol and diatrizoate in rabbits. Iotrolan induced no renal dysfunction and diuresis where iopamidol induced diuresis in rats. Effect of iotrolan on the blood coagulation was similar to nonionic monomers and less than diatrizoate in rabbits. Because of its isotonicity, iotrolan induced little water shift in the blood vessel and urinary tract, which would result in good efficacy and tolerability. These results suggest that iotrolan is superior to ionic and nonionic monomers for angiography and urography.     

Diagnostic efficacy of excretory urography with low-dose, nonionic contrast media.

A prospective, randomized, physician-blinded study was conducted to determine whether a smaller dose of low-osmolar, nonionic contrast medium can provide diagnostic information on excretory urograms equivalent to that obtained with higher doses of ionic and nonionic contrast agents. One hundred fifty adult patients who underwent excretory urography received a high-dose ionic contrast medium (diatrizoate sodium), high-dose nonionic contrast medium (iohexol), or low-dose nonionic contrast medium (iohexol). All urograms were scored for diagnostic quality. No difference in urographic quality was detected among the different doses of contrast media. The lower dose of low-osmolar nonionic contrast medium provided equivalent diagnostic information. The quality of the nephrotomograms, ureteral image, and overall image was slightly greater with diatrizoate than with a small dose of iohexol, but the difference was not significant. This study suggests that excretory urograms obtained in relatively healthy, well-prepared patients with smaller, less expensive doses of a nonionic contrast agent are at least diagnostically equivalent to those obtained with typical higher doses of ionic and nonionic agents.     

螺旋CT双期增强扫描测定肾小球滤过率的标准化方案探讨

MSCT多期增强扫描测定肾小球滤过率(glomerularfiltration rate,GFR)可以在显示肾脏精细解剖的同时,提供单侧肾脏甚至肾脏局部区域的功能情况,而不必额外注射对比剂,是目前肾脏功能影像学的一个研究方面~([1-3]).本研究通过对30例患者应用改良后的MSCT双期增强扫描标准化方案,评价其测定GFR的可行性和准确性,以及自动测量软件的可靠性.     

肾脏常规皮质髓质CT平扫及增强扫描与肾功能的相关性研究

目的 探讨肾脏常规皮质、髓质CT平扫与增强扫描与肾小球滤过率(GFR)的关系.方法 回顾性分析35例单侧肾后性梗阻性肾积水患者16层螺旋CT平扫与增强皮质期影像.以SPECT的GFR为参考标准,将35例患者按照肾功能结果分为4组:正常组,轻、中、重度肾功能损害组.测量计算患肾肾皮、髓质增强程度及各项比值.采用单因素方差分析比较上述指标的差异,采用Pearson法与GFR进行相关性分析.结果 肾功能正常组及轻、中、重度受损组患肾肾皮质增强程度(CT皮增-CT皮平)分别为(154.98±28.70)、(122.67±39.32)、(81.30±32.94)和(57.60±23.49)HU、增强后患侧与健侧皮质的CT值比值(CT患皮/CT健皮)分别为0.97±0.09、0.79±0.18、0.64±0.24和0.51±0.13、患侧及健侧髓质的CT值比值(CT患髓/CT健髓)分别为0.98±0.26、0.89±0.18、0.86±0.31和0.75±0.28、患侧皮髓质CT值比值(CT患皮/CT患髓)分别为2.76±0.35、2.35±0.79、1.83±0.68和1.73±0.28、患侧皮髓质CT值比值与健侧皮髓质CT值比值之比[(CT患皮/CT患髓)/(CT健皮/CT健髓)]分别为1.00±0.28、0.89±0.34、0.75±0.17和0.69±0.14,差异有统计学意义(P<0.05).肾皮质CT值增强程度与GFR呈高度正相关(r=0.887,P<0.01),肾髓质CT值增强程度与GFR无相关性(r=0.203,P>0.05),患侧与健侧皮质增强CT比值与GFR呈高度正相关(r=0.872,P<0.01),患侧及健侧髓质增强CT比值与GFR呈中度正相关(r=0.504,P<0.01),患侧皮髓质增强CT值比值与GFR呈高度正相关(r=0.772,P<0.01),患侧皮髓质增强CT比值与健侧皮髓质增强CT比值之比与GFR呈中度正相关(r=0.663,P<0.01).以皮质期CT患皮/CT患髓高(≥2.60)、较高(2.20～2.59)、中(1.80～2.19)、低(<1.80)为判断肾功能正常、轻度损害、中度损害与重度损害的标准,对35例患肾功能SPECT结果对照,两种分组的符合率为80.0%.结论 GFR分级定量分析,不同GFR分组各肾皮质相关CT增强指标差异有统计学意义,且与GFR呈正相关,其中患侧皮髓质增强CT值比值适用于对单、双侧梗阻患者单肾功能进行评价,可对肾后性梗阻积水肾功能损害作出半定量诊断,相对于CT灌注简单方便,X线辐射剂量低.     

Simplified estimation of glomerular filtration rate and effective renal plasma flow

A method is described for the determination of GFR and ERPF using a combined injection of ⁵¹Cr-EDTA and ¹²⁵I-iodohippurate. Plasma samples obtained at 60 min and 150 min after administration were used to determine a flow rate F assuming a monoexponential clearance of the tracers. Empirical relationships were found between F and the true GFR and ERPF determined from multiple sampling and multi-exponential analysis of the clearance curves. The method was shown to be superior to previously published methods involving one or two samples. GRF was calculated with a standard deviation (SD) of only 3.3 ml/min when compared to the multiple sample technique (the reference method), whereas the best estimate from a single sample had a SD of 6.3 ml/min. An improvement in accuracy of ERPF estimation was achieved for values of flow of less than 200 ml/min when the SD was only 9.3 ml/min.