Quantitative scintigraphic parameters for the assessment of renal transplant patients

doi:10.1016/S0720-048X(97)00179-4

European Journal of Radiology

Volume 28, Issue 3, October 1998, Pages 256-269

https://doi.org/10.1016/S0720-048X(97)00179-4 Get rights and content

Abstract

Radionuclide renal diagnostic studies play an important role in assessing renal allograft function especially in the early post transplant period. In the last two decades various quantitative parameters have been derived from the radionuclide renogram to facilitate and confirm the changes in perfusion and/or function of the kidney allograft. In this review article we discuss the quantitative parameters that have been used to assess graft condition with emphasis on the early post-operative period. These quantitative methods were divided into parameters used for assessing renal graft perfusion and parameters used for evaluating parenchymal function. The blood flow in renal transplants can be quantified by measuring (a) the rate of activity appearance in the kidney graft; (b) the ratio of the integral activity under the transplanted kidney and arterial curves e.g. Hilson’s perfusion index and Kircher's kidney/aortic ratio; (c) calculating the renal vascular transit time by deconvolution analysis. The literature overview on these parameters showed us that they have some practical disadvantages of requiring high quality bolus injection and numerical variations related to changes in the site and size of regions of interest. In addition, the perfusion parameter values suffer from significant overlap when various graft pathologies coexist. Quantitative evaluation of the graft parenchymal extraction and excretion was assessed by parameters derived from ¹²³I/¹³¹I-OIH, ^99mTc-DTPA or ^99mTc-MAG3 renograms. We review in this article a number of parenchymal parameters which include (1) plasma clearance methods like glomerular filtration rate (GFR) and effective renal plasma flow (ERPF); (2) renal transit times such as parenchymal mean transit time, T_max, T_1/2; (3) parenchymal uptake and excretion indices as the accumulation index, graft uptake capacity at 2 and 10 min, excretion index and elimination index. These indices, however, are non-specific and far from defining a specific cause for graft parenchymal dysfunction. In conclusion, despite that the literature is replete with mathematical strategies for quantitating perfusion and parenchymal functions, none of these have enough diagnostic power for specific diagnosis of graft dysfunction. In addition, no universal agreement on the use of certain quantitation parameters in transplant patients has been reached.

Introduction

In the last two decades various quantitative parameters from dynamic renal scintigraphy have been derived to facilitate the detection and follow-up of renal graft pathology [1]. The radionuclide renogram offers possibilities for the quantitative evaluation of the graft function. This is usually based on the analysis of the three phases of the renogram originally described by Taplin et al. [2]. The first phase of this division corresponds to the transit of the tracer bolus through the renal blood vessels. In the second phase the nephrons extract the radiotracer from the blood to be excreted into urine by either glomerular filtration and/or tubular excretion. The third phase corresponds to the drainage of the pelvicalcyeal system (Fig. 1). In order to evaluate the handling of the tracer by the kidney in a quantitative way various indices have been proposed [3]. The quantitative parameters that have been used to assess graft function in the post-operative period will be discussed comprehensively in this review, and have been listed in Table 1.

Section snippets

Assessment of renal graft perfusion

Damage to the microcirculation of the renal graft is an early event in the course of allograft dysfunction, usually preceding measurable functional derangements in the transplanted kidney [4]. Because recovery of the graft function is largely dependent on perfusion, the assessment of perfusion in the early post-transplant period is of utmost importance. Renal perfusion imaging (RPI) is defined as the rapid dynamic renal examination carried out in the 1st min after administration of

Assessment of parenchymal extraction and excretion

Radiopharmaceuticals with a well-defined mode of pharmacological handling such as [^99mTc]DTPA, [¹³¹I]hippuran and [^99mTc]MAG3 are excellent agents for the evaluation of graft function. Quantitative evaluation of the graft parenchymal function were first described as parameters applied to the [¹³¹I]OIH renograms. They include time to peak of the renogram (T_max), half time of the elimination phase (T_1/2), ratio of bladder and kidney curve heights, bladder appearance time, and kidney to background

Conclusion

Radionuclide scintigraphy of the renal transplants has assumed an important role, especially if carried out serially, in monitoring graft function in the post-transplant period. Both qualitative and quantitative information on the graft condition can be obtained from radionuclide renography. The literature is however replete with mathematical strategies for quantitating perfusion and parenchymal functions but none of these have enough diagnostic power for specific diagnosis of graft dysfunction.

Acknowledgements

The authors would like to thank Tilly Hagendoorn for her expert secretarial assistance in the preparation of this manuscript.

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Quantitative scintigraphic parameters for the assessment of renal transplant patients

Abstract

Introduction

Section snippets

Assessment of renal graft perfusion

Assessment of parenchymal extraction and excretion

Conclusion

Acknowledgements

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Semin Nucl Med

J Urol

Semin Nucl Med

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Urol Radiol

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Eur J Nucl Med

Dynamic and static renal imaging

Correlation of gamma camera and flow meter determined renal blood flow measurements (Abstract)

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Dynamic renal transplant imaging with Tc-99m DTPA (Sn) supplemented by a transplant perfusion index in the management of renal transplants

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Improvement in quantitative data analyses by numerical deconvolution techniques

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