title: Significance of early tubular extraction in the first minute of Tc-99m MAG3 renal transplant scintigraphy.
abstract: Renal transplant perfusion curves obtained using Tc-99m MAG3 differ from those with Tc-99m DTPA. The perfusion curve can be divided into a first phase (up to the first-pass peak) and a second phase (the curve after the initial peak). The second phase of the MAG3 perfusion curve is usually ascending in contrast to the descending Tc-99m DTPA curve. This ascending MAG3 curve reflects early tubular extraction of MAG3. However, the second phase of the MAG3 curve is sometimes flat or descending. We hypothesized that a flat or descending curve reflects poor early tubular extraction and therefore graft dysfunction. Ninety-two studies of 59' renal transplant patients were retrospectively reviewed. The second phase of the perfusion curve was visually classified as ascending, flat, or descending. 77.2% of studies had ascending curves, 16.3% flat curves, and 6.5% descending curves. A descending curve had a positive predictive value (PPV) of 100% for medical graft dysfunction, while a flat curve had a PPV of 93.3%. A nonascending second phase curve was specific (96.4%) but not sensitive (33.9%) for graft dysfunction. Patients with acute tubular necrosis were not significantly more likely to have a nonascending curve than those with acute rejection. There was no significant difference in creatinine level between patients with medical graft dysfunction and ascending vs. nonascending curves. A nonascending second phase Tc-99m MAG3 perfusion curve is predictive for graft dysfunction. An ascending curve is nonspecific and can be seen in both normally and poorly functioning grafts.
authors.affiliation: Division of Nuclear Medicine, Hospital of the University of Pennsylvania, Philadelphia 19104, USA.
authors.forename: E
authors.initials: E
authors.lastname: Lin
authors.forename: A
authors.initials: A
authors.lastname: Alavi
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006084:Graft Rejection / Q000000981:diagnostic imaging; D006801:Humans; D016030:Kidney Transplantation / Q000000981:diagnostic imaging* / Q000502:physiology; D007683:Kidney Tubular Necrosis, Acute / Q000000981:diagnostic imaging / Q000209:etiology; D007684:Kidney Tubules / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011237:Predictive Value of Tests; D011866:Radioisotope Renography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D017263:Technetium Tc 99m Mertiatide; D016284:Technetium Tc 99m Pentetate; D013997:Time Factors
chemical_list: D019275:Radiopharmaceuticals; D017263:Technetium Tc 99m Mertiatide; D016284:Technetium Tc 99m Pentetate