Year : 2011 | Volume
: 26 | Issue : 5 | Page : 24--25
|How to cite this article:|
. Nephro-Urology.Indian J Nucl Med 2011;26:24-25
|How to cite this URL:|
. Nephro-Urology. Indian J Nucl Med [serial online] 2011 [cited 2021 Oct 28 ];26:24-25
Available from: https://www.ijnm.in/text.asp?2011/26/5/24/90730
A software program and database system for GFR estimation by plasma sampling method
Ashish Kumar Jha, Anand Zade, V Rangarajan, Sneha M, Priya M, Beena Shetye, Sneha Shah, Archi Agrawal
Bio Imaging Unit, Tata Memorial Hospital, Parel, Mumbai, India
Objective: Glomerular filtration rate (GFR) is an indicator of renal function. In clinical practice, GFR is often estimated by Tc-99m-DTPA Scintigraphy This technique is widely used due to its simplicity and ability to provide differential GFR values for each kidney. However, it suffers from a drawback, that these GFR values are highly dependent on the processing parameters and may overestimate the GFR when large ROI's are drawn in hydronephrotic kidneys. The GFR values are often underestimated in pediatric patients due to high ECF volume. GFR value is of critical importance to take decisions such as discontinuation of nephrotoxic chemotherapeautic regime, post renal transplant evaluation etc. Hence there is a need for a more accurate and reproducible method for estimation of GFR. Plasma sampling method is very promising, accurate and reproducible technique to provide absolute GFR. Though this method is more accurate, it is not popular and not routinely used as it is cumbersome and technically demanding. We have developed a new software system for GFR estimation by two plasma sampling method. It is very easy and useful software, where we can calculate and store raw data for future reference. Materials and Methods: The program has been written in Visual Basic (VB 6.0) Software and MS Access Database on Personal computer. The formulas used for calculating GFR is the Russel's equation for two sample method. This software is very easy, self instructional and very user friendly with separately designed Patient Registration Page, Requisition Page, Data Entry Page and GFR Calculation Page. This software enables us to calculate GFR by either weighing or counting method. There is provision to estimate absolute GFR for individual kidney by entering differential GFR obtained from scintigraphy method. Results: The accuracy and reproducibility of the program have been tested with available raw data of normal patients and compared with GFR estimated by Gamma camera (Gate's) method. Conclusion: This is very useful and accurate software, not only for the routine clinical use but also for research and development. Stored data can be retrieved at any time during follow. This program is very promising and makes entire process very simple and user friendly.
Estimation of GFR in adult Indian population: A comparison between various prediction equations using S. Creatinine, DTPA scan using Gates protocol and plasma clearance of Tc99m-DTPA
Shefali M Gokhale, AV Mulay 1
Department of Nuclear Medicine and 1 Nephrology, Inlaks and Budhrani Hospital, Pune, Maharashtra, India
Introduction and Aims: Accurate estimation of glomerular filtration rate (GFR) is an important part of evaluation of kidney function. Renal scan using radiolabelled diethylenetriamine pentaacetic acid (Tc99m-DTPA) by Gates protocol is commonly used for estimating GFR. We compared GFR measured by plasma clearance of Tc99m-DTPA with scitigraphically estimated GFR by Gates protocol and also with serum creatinine based predicting equations (Cockroft-Gault formula, 4-variable MDRD equation, CKD-EPI equation). Materials and Methods: We measured GFR by plasma clearance (GFRp) of Tc99m-DTPA using multiple sampling at 120 minutes, 180 minutes and 240 minutes after injection of Tc99m-DTPA. A well type counter was used to measure required counts from the blood samples. We also determined GFR by Tc99m-DTPA renal scan (GFRs) using GE Hawkeye 4 dual headed gamma camera and Gates protocol. The protocols for both methods were standardized. Serum creatinine was measured by modified Jaffe's reaction on an EM360 Transasia machine using manufacturer provided reagents. We used Cockroft-Gault equation (GFR CG ) normalized to body surface area, 4-variable MDRD equation (GFR MDRD ) and recently described CKD-EPI equation (GFR CKD-EPI )for estimating GFR from serum creatinine. 1,2 We then compared GFRp (gold standard for measuring GFR) with other methods by calculating Pearson and Spearman correlation coefficient and bias and precision of the other three methods. Bias was defined as mean difference between GFRp and GFR estimated using other methods. 1 Precision was defined as standard deviation of the difference. 1 Results: We included 44 patients (27 Male, 17 Female) with mean(SD) age of 50.2 (15.6) years. Mean(SD) GFRp was 82.3 (29.4) ml/min/1.73m 2 . GFR estimated by all three estimating equations correlated better than GFRs with GFRp. For estimating GFRp, GFR CG had the least bias but GFR CKD-EPI also was the most precise [Table 1]. GFRs overestimated GFRp by mean(SD) 7.2 (43.0) ml/min/1.73m 2 .
Conclusion: Serum creatinine based prediction equations are superior to Tc99m-DTPA scan using Gates protocol for estimating GFR. Tc99m-DTPA based plasma sampling method combined with a DTPA scan not only provides accurate estimation of GFR but also gives complete information on the split function and drainage pattern of kidneys.
Computation of differential renal function of ectopic kidneys by anterior renogram
GS Muthu, S Mitra
Departments of Nuclear Medicine and Immuno Assay, Tata Main Hospital, Jamshedpur, West Bengal, India
Introduction: Variation in the kidney depth and the tissue attenuation for the anteirorly placed ectopic kidneys leads to underestimation of computed quantitative parameters in the conventional posterior renogram. Aim: This prospective study was undertaken to compute the Differential Renal Function (DRF) of ectopic kidneys and to analyze the difference in the anterior and posterior views and therefore to determine the optimal method to compute the Glomerular Filtration Rate GFR and the DRF. Materials and Methods: Prospective study was done on 29 patients with suspected or known ectopic kidneys from January 2007 to June 2011. Two sets of dynamic images were acquired in both anterior and posterior detectors with the single injection of Tc99m DTPA in a GE Millennium dual head gamma camera. A tailor-made software was developed to process the ectopic kidney renogram analysis with the data sets from the anterior dataset in the Xeleris system. GFR value of the normal and ectopic kidney was taken from the posterior and anterior renogram respectively. Differential Renal Function was indirectly computed from the GFR values observed for the normal and ectopic kidneys using an indigenously developed formula. Results: Higher value of GFR of ectopic kidney was observed from anterior data set than from that of the posterior data set in all the patients ( p0 <0.001). Only one patient showed lower DRF value of the ectopic kidney. Other 26 patients showed DRF values greater than 40%. Conclusion: Abnormal DRF values of the ectopic kidneys were assessed better with this indigenously developed method. Anterior view gave a better calculation of DRF and GFR for the ectopic kidneys.
Importance of isotope scan amongst the imaging modalities
Srujan Kumar, N Pandit, Rajessh Kumar, S Bhushan, Vasumathi, S Oomen, Dinesh Rawat
Department of Nuclear Medicine, Shirdi Sai Baba Cancer Hospital, Manipal University, Manipal, India
Introduction: Isotope scanning plays an important role in evaluating the functional status as well as the anatomical location of the organs. Objective: A 54 yr old male patient with h/o alebric kyphoscoliosis and pes ex cavarm and a diagnosis of b/l hydronephrosis (by USG and CT abdomen) was referred to the department of nuclear medicine for renal scintigraphy from urology. The urologist wanted to know about the relative function and the clearance pattern of the hydronephrotic kidneys before going for surgical intervention. Materials and Methods: Tc-99m DTPA and gamma camera (Ge infinia hawkeye) Tc-99m DTPA of 5 mci was injected as a i.v bolus under the gamma camera with posterior detector active and continued the scan for 30 min with the parameters of 64×64 matrix size with lehr collimator. The scanning phases were 30 frames (2 sec/frame) for 60 sec - perfusion phase. 112 Frames(15 sec/frame) for 1680sec-uptake and clearance phase. Results: A functioning renal tissue was seen in mid-abdominal region in the early frames of perfusion phase, that mass is lightly trapped Tc99m-DTPA in the uptake phase and shows the sluggish clearance. Conclusion: A mass which was noted at the mid-abdominal region looks like a kidney and we processed it. It gives the perfusion curve, functional and clearance curve. This scan suggested that the kidneys to this patient is not at original situ and it is ectopic to the abdominal region. It is revealed by the Tc99m-DTPA scan where the other modalities unable to explain the anatomical localisation as well as functional status of the kidneys. Based on the report of the Tc99m-DTPA renogram, urologist opted for a medication to the patient without undergoing for the nephrectomy.