Accurate and precise plasma clearance measurement using four 99mTc-DTPA plasma samples over 4 h. Issue 1 (January 2016)

• Record Type: Journal Article
• Authors: Wanasundara, Surajith N.; Wesolowski, Michal J.; Barnfield, Mark C.; Waller, Michael L.; Murray, Anthony W.; Burniston, Maria T.; Babyn, Paul S.; Wesolowski, Carl A.
• Is Part Of: Nuclear medicine communications. Volume 37:Issue 1(2016:Jan.)
• Publication Date: 2016-01
• Subjects: Biexponential method -- glomerular filtration rate -- noncompartmental methods -- numerical integration -- plasma clearance -- tikhonov regularization; Nuclear medicine -- Periodicals; 616.07575
• DOI: 10.1097/MNM.0000000000000405
• Languages: English
• ISSNs: 0143-3636

Abstract

Abstract : Objectives: Glomerular filtration rate can be measured as the plasma clearance (CL) of a glomerular filtration rate marker despite body fluid disturbances using numerous, prolonged time samples. We desire a simplified technique without compromised accuracy and precision. Materials and methods: We compared CL values derived from two plasma concentration curve area methods – (a) biexponential fitting [CL (E2)] and (b) Tikhonov adaptively regularized gamma variate fitting [CL (Tk-GV)] – for 4 versus 8 h time samplings from 412 99m Tc-DTPA studies in 142 patients, mostly paediatric patients, with suspected fluid disturbances. Results: CL (Tk-GV) from four samples/4 h and from nine samples/8 h, both accurately and precisely agreed with the standard, which was taken to be nine samples/8 h CL from (noncompartmental) numerical integration [CL (NI)]. The E2 method, four samples/4 h, and nine samples/8 h median CL values significantly overestimated the CL (NI) values by 4.9 and 3.8%, respectively. Conclusion: Compared with the standard, CL (E2) from four samples/4 h and from nine samples/8 h proved to be the most inaccurate and imprecise method examined, and can be replaced by better methods for calculating CL. The CL (Tk-GV) can be used to reduce sampling time in half from 8 to 4 h and from nine to four samples for a precise and accurate, yet more easily tolerated and simplified test.