Comparison of 99mTc-HEPIDA and 99mTc-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 (99mTc-HEPIDA) has been used in recent decades. Because of recent problems with manufacturing and delivery of 99mTc-HEPIDA, an investigation was undertaken with the aim of testing whether a more widely available 99mTc-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, 99mTc-HEPIDA and 99mTc-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 99mTc-MBrIDA and hepatic clearance of 99mTc-HEPIDA. Correlation coefficients of 99mTc-MBrIDA clearance and the biochemical test results attained somewhat lower values than for 99mTc-HEPIDA clearance. Similarly, values of χ2 test of independence of 99mTc-MBrIDA clearances and test results were also less close than for 99mTc-HEPIDA clearances. Factorial analysis showed that common factor loading is greatest for hepatic clearance of 99mTc-HEPIDA; the values of two loadings of 99mTc-MBrIDA clearances are very close, but somewhat lower than those for 99mTc-HEPIDA. CONCLUSIONS. From the performed investigations it is possible to conclude that 99mTc-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 99mTc-HEPIDA

Usefulness of parametric renal clearance images in the assessment of basic risk factors for renalnal clearance images in the assessment of basic risk factors for renal scarring in children with recurrent urinary tract infections

BACKGROUND: Clinically confirmed incidents of acute pyelonephritis (APN) following recurrent infections of urinary tract (UTI) form basic risk factors for renal scarring in children. Vesico-uretheral reflux (VUR) of higher grade is additional risk factor for this scarring. Opinions on diagnostic value of summed sequential images of renal uptake phase (SUM) of dynamic renal scintigraphy in detection of renal scars are diverse. However, several publications point to higher diagnostic efficacy of clearance parametric images (PAR) generated from this study. The aim of the study. To establish a clinical value of parametric renal clearance images in detection of renal scarring. MATERIAL AND METHODS: A prospective study was performed in a group of 91 children at the age of 4 to 18 years with recurrent UTI. Clinically documented incidents of APN were noted in 32 children: in 8 cases — one and in the remaining 24 — 2 to 5 (mean 3) incidents. In the remaining 59 patients only infections of the lower part of urinary tract were diagnosed. Static renal 99mTc-DMSA SPECT study and after 2–4 days dynamic renal studies (99mTc-EC) were performed in every patient not earlier than 6 months after the last documented incident of UTI. PAR images generated from a dynamic study by in-house developed software and SUM images were compared with a gold standard SPECT study. RESULTS: Percentages of children with detected renal scar(s) with SPECT and PAR methods amounted to 55% and 54%, respectively and were statistically significantly higher (p < 0.0001) than with SUM method — 31%. Scars in children with history of APN detected with SPECT and PAR methods were significantly more frequent than with infections of only lower part of urinary tract (72% vs. 46%; p = 0.017 and 69% vs. 46%; p = 0.036, respectively). A SUM method did not reveal statistically significant differences between frequencies of detection of scars in groups specified above — 38% vs. 27% (p = 0.31). Both SPECT and PAR methods showed also that frequencies of occurrence of renal scars in children with higher grades of VUR were higher than without or with lower grades of VUR: 79% vs. 50% (p = 0.048) and 79% vs. 49% (p = 0.04). A SUM method did not reveal higher frequency of renal scars in children with high VUR grades: 36% vs. 30% (p = 0.44). CONCLUSION: Results obtained with PAR and SPECT methods were similar. An advantage of PAR over SUM images obtained from a dynamic renal scintigraphy in detection of renal scars in children with UTI was confirmed