Assessment of clinical usefulness of parametric clearance images in diagnosis of kidney cicatrisation in children with chronic infections of the urinary tract.

BACKGROUND: Cicatrisation of the renal cortex is closely related to chronic infections of the urinary system. Static renal scintigraphy is used as the method enabling detection of local defects of radiopharmaceutical uptake, and is treated as the "gold standard" in the diagnosis of renal scars. The aim of the reported investigation was a comparison of the diagnostic efficacy of parametric clearance images and the conventional summation images - obtained from dynamic scintigraphy - in the detection of local defects of renal function. As the "gold standard" for the above comparison, the static scintigraphy of kidneys was accepted. MATERIAL AND METHODS: Forty-one patients (age 4-19 years), 28 girls and 13 boys, participated in the study. Altogether, 73 kidneys were analyzed (in 9 patients, only one kidney). In each patient dynamic renal scintigraphy was performed after IV administration of 99mTc EC (ethylenedicysteine) and static planar renal scintigraphy using 99mTc-DMSA (dimercaptosuccinic acid) as a reference method. From the dynamic study, summation and parametric clearance images were generated. Each kidney was divided into 3 segments (upper, middle, lower); altogether 219 segments were evaluated by modified Howard's scale. Planar and oblique projection images were compared with corresponding summation and parametric clearance images. RESULTS AND CONCLUSIONS: Parametric clearance imaging has a higher sensitivity and accuracy for detection of regional post-inflammatory changes in the kidneys than conventional summation images (p < 0.05) and shows parenchymal changes similarly to static scintigraphy (high Cohen's kappa index).

Comparison of (99m)Tc-HEPIDA and (99m)Tc-MBrIDA from the standpoint of hepatic clearance determination-- preliminary communication.

BACKGROUND. In order to evaluate the functional capacity of the liver by means of clearance determination, the derivative of iminodiacetic acid ((99m)Tc-HEPIDA) has been used in recent decades. Because of recent problems with manufacturing and delivery of (99m)Tc-HEPIDA, an investigation was undertaken with the aim of testing whether a more widely available (99m)Tc-MBrIDA could be used for clearance determination and whether hepatic clearance measured with the use of this compound provides a similarly useful test of hepatic function. MATERIAL AND METHODS. Comparative investigations were performed in 73 patients of both sexes. The state of the efficiency of liver parenchyma was determined based on seven widely used biochemical tests, i.e. levels of: bilirubin, albumin, and gamma globulin; activity of AST, ALT, GGTP, and prothrombin index. The clearances of both radiopharmaceuticals, (99m)Tc-HEPIDA and (99m)Tc-MBrIDA, were determined by means of multisample technique. The results of determination were correlated among themselves and with the results of biochemical tests. The set of results of all estimations allowed a factorial analysis to be performed to find a common factor and to compute the values of factor loadings in particular tests. RESULTS. Obvious correlation between plasma and hepatic clearances of both radiopharmaceuticals was obtained and between plasma clearance of (99m)Tc-MBrIDA and hepatic clearance of (99m)Tc-HEPIDA. Correlation coefficients of (99m)Tc-MBrIDA clearance and the biochemical test results attained somewhat lower values than for (99m)Tc-HEPIDA clearance. Similarly, values of chi(2) test of independence of (99m)Tc-MBrIDA clearances and test results were also less close than for (99m)Tc-HEPIDA clearances. Factorial analysis showed that common factor loading is greatest for hepatic clearance of (99m)Tc-HEPIDA; the values of two loadings of (99m)Tc-MBrIDA clearances are very close, but somewhat lower than those for (99m)Tc-HEPIDA. CONCLUSIONS. From the performed investigations it is possible to conclude that (99m)Tc-MBrIDA clearances may be used for the evaluation of liver parenchyma performance, even if the results may not be as certain as those obtained using (99m)Tc-HEPIDA.

Conventional and parametric kidney scintigrams - reproducibility of semiquantitative image evaluation.

BACKGROUND: Parametric kidney scintigraphy gives the possibility of regional function distribution assessment of these organs; the clinical application of the method has thus far been limited. The usefulness of the method for the assessment of postinflammatory scars and diabetic nephropathy has been demonstrated. Preliminary data also indicate that this type of imaging allows the assessment of kidney function after extracorporeal shock wave lithotripsy. The aim of this study was the evaluation of the reproducibility of semiquantitative parametric kidney image evaluation. MATERIAL AND METHODS: The results of 98 dynamic kidney scintigraphic series were evaluated, obtained from examination of 44 patients (20 males, 24 females) with nephrolithiasis, who had been treated by means of lithotripsy. The semiquantitative assessment involved conventional renoscintigraphic images obtained from summation of scintigraphic serial records in the secretory phase, and parametric clearance images. A 5-level score was applied for assessment of both types of images, based upon numbers of detected defects of the regional function (0 - no defects; 1, 2, 3 - for 1, 2 or 3 defects, and 4 for higher numbers). Altogether, 196 kidney images were evaluated. The assessment was performed independently by 2 observers: A - an experienced specialist in nuclear medicine, who evaluated the images twice, and B - a resident physician with limited experience in the field. RESULTS: The agreement between the two evaluations by the specialist (intra-observer test) reached a level of 96% for conventional images and 90% for the parametric ones. In the inter-observer test, full agreement reached the levels of 84% and 71% for conventional and parametric images, respectively. If +/- 1 degree of the image score was taken as factual agreement, the intra-observer concordance reached 100%, and for inter-observer comparison, the agreement reached 99% and 97% for conventional and parametric images, respectively. CONCLUSIONS: The concordance of image assessment for conventional and parametric images is very good. In observations by two physicians, a somewhat closer agreement was reached for conventional than for parametric images; the difference between the two series of image assessments was small.

Parametric clearance kidney scintigrams; diagnostic potential in diabetes.

BACKGROUND: The diagnostic usefulness of parametric clearance kidney images was studied in the early diagnosis of diabetic nephropathy, juxtaposed with conventional dynamic urinary investigation (renoscintigraphy) combined with deconvolution procedure of renal and blood time activity curves and determination of plasma clearance of (99m)Tc-ethylenedicysteine ((99m)Tc-EC). MATERIAL AND METHODS: The investigation was performed on a group of 70 individuals (41 males, 29 females) in whom diabetes type 1 was diagnosed (age 10 to 30 y.; mean 19 y.) and on a control group of 35 healthy individuals (15 males, 20 females) in the age-bracket of 18-25 years (mean 19 y.). In all subjects studied, renoscintigraphy was performed after administration of (99m)Tc-EC (activity 40-120 MBq) combined with determination of urinary clearance (ERPF) of the radiopharmaceutical. The renographic curves were evaluated taking into account their shape and individual share of each kidney, and the clearance function was calculated (RClr). From analysis of the time-activity, kidney curves T(max) and T(1/2) were assessed. In addition, the mean (99m)Tc-EC transport time through the complete kidney (MTT) and organ's parenchyma (PTT) were calculated from results of deconvolution of the curve. From the dynamic urinary system study, conventional images of radiopharmaceutical distribution in the kidneys in the secretion phase were obtained. The parametric clearance images were also computed on the basis of relative clearance values in all the pixels of both kidney regions of interest. The disturbances in kidney function were assessed separately by means of conventional scintigram analysis and of corresponding parametric images. A three-stage classification was used in both cases for the evaluation of abnormal findings in the kidneys RESULTS AND CONCLUSIONS: In all studied individuals, the (99m)Tc-EC (ERPF) clearance values were within the normal range. When renographic time activity curves were considered the flattening of the curves (III phase) was more frequent in diabetic individuals than in the controls (39.3% vs. 15.7%; p = 0.001). The shape of the curves in phases I and II were normal in all studied individuals of both groups. There were no differences observed between mean values of T(max), T(1/2) and PTT in diabetics and controls. However, mean MTT values were significantly higher in diabetics than in controls (p = 0.02). In conventional summation images (phase II of the renograms), there were no significant differences in frequency of defects in kidney parenchyma diabetics and controls (4.3% vs. 2.9%). In contrast, analysis of parametric kidney clearance images revealed that parenchyma defects were found with significantly greater frequency in diabetic individuals (35.7%) than in control subjects (8.6%; p < 0.001). Summarizing the findings, it appears that parametric clearance kidney images reveal local deviations of renal uptake and secretory function while conventional indicators of renal function are still in the normal range. This observation points to the fact that clearance parametric images may have potential value in the early diagnosis of diabetic nephropathy, and perhaps in other types of renal damage. Incorporation of parametric images into the dynamic study of the urinary system may be promising when early detection of kidney damage seems vital.

(99m)Tc-HEPIDA hepatic clearance as a diagnostic tool: usefulness of a single sample plasma and hepatic clearance of (99m)Tc-HEPIDA for assessment of hepatic parenchyma performance.

BACKGROUND: A simplified method of (99m)Tc-HEPIDA clearance determination, both plasma and hepatic, depends upon measuring the radiopharmaceutical concentration in plasma of a blood sample taken once in the time range from 68-83 min after injection of compound, and measurement of activity voided (excreted) with urine about five minutes after blood sampling. The aim of the present study was to analyze the clinical usefulness of both clearances, as determined by the simplified method in view of the diagnostic usefulness of both clearances (particularly of hepatic clearance) as determined by the respective multisampling method. MATERIAL AND METHODS: For the analysis, archived data of studies in 134 individuals (48 healthy individuals and 86 patients with chronic liver parenchyma damage) were used, in which plasma clearance (Cl(Pl)) and hepatic clearance (Cl(Hp)) (99m)Tc -HEPIDA were determined by the standard multisample method--the values of such determined clearances constituted clearance referential values for further comparative analyses. The clearances Cl(Pl) and Cl(Hp) were determined by the simplified method separately for three blood sampling times of: 60, 75 and 90 min, using the same archived data for calculation of corresponding concentrations of (99m)Tc-HEPIDA in plasma. For urinary clearances--which were necessary for calculation of Cl(Hp)--archived data were utilized on activity contained in voided urine (at about 95 min.). The clinical reference system used here was the semi-quantitative assessment of liver function, performed on the basis of commonly used basic biochemical indices (AST, ALT, GGTP, bilirubin, albumin and gammaglobulin in serum, proteinogram and prothrombin index). For each test there were 4 categories of results (sub-ranges) selected, which were ranked from 0 to 3. For each patient the ranks for the results of each test were summed, giving a total sum (called SP). These latter sums of ranks served as a reference system, characterizing liver condition (performance) in each individual. RESULTS: Clearance, Cl(Pl) and Cl(Hp), values, obtained by a simplified method, were correlated with respective values determined by the multisampling method, and with ranks (SP) representing classification of degree of hepatic parenchyma damage--SP. On the basis of the attribute independence Chi(2) test, the coherence of clearances (simplified determination) with SP was assessed. Also, analysis of variance of SP-values and clearance was performed using Spearman's theory for testing the correlation of non-continuous variables. By factorial analysis a factor responsible for changes in individual quantities (results of biochemical tests and (99m)Tc-HEPIDA clearances) was computed. Its loading was determined for each individual quantity. During analysis for each moment of blood sampling tight correlations of clearance values, obtained by the simplified method, were determined with referential values. The closest correlation was obtained for blood sampling at 75 min. It was found that there are negative correlations between values of hepatic and plasmatic clearances and SP. The values of r obtained for Cl(Hp) are close to those obtained for analogical correlations by multisampling methods. However, the values of correlation coefficient obtained for Cl(Pl) by single sample method are greater than those for Cl(Pl) determined by multisampling method. CONCLUSIONS: Factor loading, known as "liver incapacity", is greater for Cl(Hp) determined by single sample method, but lower than comparable hepatic clearance loading determined by the multi-sample procedure. Values of incapacity factor for Cl(Pl) are lower than for Cl(Hp), but the lowest value was obtained for Cl(Pl) determined by the multisampling method. Obtained values Chi(2), r and loading of incapacity factor speak in favour of the correlations between the degree of hepatic parenchyma performance and the values of clearances determined by the simplified method. However, this correlation is closer for Cl(Hp) than for Cl(Pl). In view of such a distinct correlation, there is good justification for the implementation of the simplified method for the determination of hepatic clearances used in diagnostic analysis of hepatic performance.

Specific 99mTC-HEPIDA hepatic clearance--essential value ranges from a clinical stand-point.

BACKGROUND: Determinations of plasma 99mTc-HEPIDA clearance (ClPl) have been performed in some centres for 30 years to assess liver parenchyma damage, mostly for monitoring of organ performance in the course of various diseases. The main disadvantage of such a procedure rests with the fact that elimination of the compound from the system occurs not only via the liver and gall ducts, but also via the urinary route; the contribution of the latter compound being quite variable. This circumstance may lead to false assessment of liver parenchyma performance. A method has been developed therefore for assessment of specific hepatic clearance of 99mTc-HEPIDA (Cl(Hp)). Using this method it was demonstrated that results of Cl(Hp) correlated better with independently assessed degrees of liver impairment than did the values of ClPl. MATERIAL AND METHODS: To delineate ranges of Cl(Hp) that would provide valuable clinical information 134 individuals were studied, of whom 48 served as healthy controls and 86 had varying degrees of livers function impairment, resulting from various chronic diseases affecting the organs functional capacity. The latter was assessed on the basis of a series of commonly used biochemical indicators. RESULTS AND CONCLUSIONS: For delineation of meaningful ranges of 99mTc-HEPIDA specific hepatic clearance ROC curve method was used. The following results were obtained: Cl(Hp) >or= 150 ml min(-1) 1.72 m(-2)--excludes with high probability presence of substantial liver parenchyma damage; Cl(Hp)

Diagnostic efficacy of parametric clearance images in detection of renal scars in children with recurrent urinary tract infections.

OBJECTIVE: Static renal scintigraphy with Tc-99m dimercaptosuccinic acid (DMSA) is considered a scintigraphic gold standard in detection of post-inflammatory renal scars. Reports on usefulness of conventional summed (SUM) Tc-99 m mercaptoacetyltriglycine (MAG3) or Tc-99m ethylene dicysteine (EC) dynamic scintigraphic images in detection of renal scarring are ambiguous and some authors emphasize low sensitivity of this method. The work aimed at assessment of a diagnostic efficacy of parametric clearance images (PAR) generated from a dynamic renal scintigraphy in detection of renal scars. METHODS: A study group consisting of 80 children (56 girls, 24 boys, age 5-18 years) with recurrent urinary tract infections (UTI) and documented one to five incidents of APN-28 children, and with recurrent UTI of the lower part of the urinary tract only-52 children. Altogether 160 kidneys were evaluated. Static renal Tc-99m DMSA SPECT scintigraphy and after 2-4 days Tc-99m EC dynamic renal scintigraphy were performed in every patient not earlier than 6 months after the last documented incident of UTI. PAR images generated from a dynamic renal scintigraphy acquired between 40 and 140 s. generated by in-house developed software and SUM images obtained in the same time period were compared with a reference Tc-99m DMSA SPECT study. RESULTS: For all kinds of images (SPECT, PAR and SUM), high indices of reproducibility were obtained-89 % (κ = 0.80), 88 % (κ = 0.78) and 89 % (κ = 0.73). Agreement in a Howard scale of a reference method (SPECT) with PAR and SUM methods amounted to 83 and 64 %, respectively (p = 0.004). Sensitivity and accuracy of PAR method as compared with SUM method were significantly higher: 89 vs. 49 % (p < 0.0001) and 88 vs. 73 % (p = 0.002), and specificity was slightly lower: 88 vs. 93 % (p = 0.043). SPECT and PAR methods revealed higher incidence of renal scars than a SUM method in patients with documented incident(s) of APN-64, 68 and 39 %, p = 0.009 and 0.008, respectively. CONCLUSION: PAR images generated from a dynamic renal scintigraphy improved sensitivity of detection of renal scars as compared with SUM images, providing a high reproducibility and diagnostic efficacy, similar to that of Tc-99m DMSA, in detection of post-inflammatory renal scarring.

99mTc-HEPIDA hepatic clearance as a diagnostic tool: usefulness of plasma and hepatic clearance for assessment of hepatic parenchyma performance.

Plasma clearance of (99m)Tc-HEPIDA (Cl(Pl)) has been used for two decades for assessment of liver function in patients with diseases of this organ. A specific determination of (99m)Tc-HEPIDA liver clearance (Cl(Hp)) has been developed that provides more direct possibility to evaluate performance of liver parenchyma. Both tests have been studied in healthy volunteers of varying age (48 individuals) and in 83 patients with varying degree of liver damage. The liver damage has been evaluated on the basis of 5 biochemical tests (AspAT, ALAT, GGTP, bilirubine serum concentration, proteinogram) and a score system used for total impairment, which was calculated for each patient. Normal range of Cl(Pl) and Cl(Hp) was determined from a study on healthy individuals (volunteers). The results seem independent of age, but show sex differences. The following values (mean +/- SD) of Cl(Hp) were found in males and females of: (181 +/- 31) ml//min/1.73 m(2) and (158 +/- 22) ml/min/1.73m(2), and of Cl(Pl) were (224 +/- 33) ml/min/1.73 m(2) and (202 +/- 25) ml/min/1.73 m(2) respectively. Accepted lower boundaries of both quantities (mean -2SD) are 115 ml/min/1.73 m(2) and 150 ml/min/1.73 m(2) correspondingly. Negative correlation of individual values of both clearances in all patients with individual score of liver damage were highly significant and correlation coefficients obtained were higher for Cl(Hp) (r = -0.63) than those for Cl(Pl) (r= -0.56). Factorial analysis was performed with the intention of seeing which of the studied factors had the highest factor loading for parenchyma performance that was assumed as the common factor responsible for correlations. The highest value was obtained for hepatic clearance (Cl(Hp)) of (99m)Tc-HEPIDA. In conclusion this quantity seems highly promising as a clinically useful test for assessment of liver performance, both in screening for liver damage and for monitoring of organ conditions during therapy and follow-up of patients.