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H Rivera-Luna

Publications and source records attributed to H Rivera-Luna.

3 recordsLinked to original sources
PubMed1993

Estimating renal function from the visual analysis of Tc-99m DTPA images.

Eleven visual parameters of Tc-99m DTPA imaging studies were evaluated to identify scintigraphic findings that best detect changes in renal function, to determine at which GFR levels they appear, and to establish criteria for visual estimation of renal function. Visual parameters were compared to in vitro GFR determinations in 41 patients. Three visual parameters offered best discrimination. The first one appeared at GFR values below 70 mL/min (sensitivity: 76%). The renal peak activity on the flow study (normally equal or greater than aortic) no longer reached the intensity of the aortic peak (pK < pA). The second parameter appeared at GFR values below 50 mL/min (sensitivity: 85%). The estimated kidney-to-liver ratio in the 2-minute image (usually 3 or greater) decreased to values less than 3. The third scintigraphic finding, pelvicalyceal system nonvisualization, appeared at GFR levels below 20 mL/min (sensitivity 100%). Use of these 3 scintigraphic findings allows categorization of patients into four functional groups: 1) severe dysfunction (GFR: 0-20 mL/min), 2) moderate to severe dysfunction (GFR: 21-50 mL/min), 3) moderate dysfunction (GFR: 50-70 mL/min), and 4) Normal study (GFR > 70 mL/min). Visual analysis of Tc-99m DTPA images does not identify patients with mildly decreased renal function (GFR: 70-90 mL/min).

Glomerular Filtration Rate↗
PubMed1990

Diagnostic and functional implications of pelvocalyceal system nonvisualization on [99m]Tc-DTPA renal images.

Most functional abnormalities observed on 99mTc-DTPA renal images probably reflect GFR changes and the functional consequences of these changes. We have noted an unexplained failure of the pelvocalyceal system to visualize in some patients during the renal imaging sequence. This led us to study the relationship between pelvocalyceal nonvisualization and GFR, and to search for plausible explanations of the absent visualization. In 41 patients with combined renal imaging and GFR determinations, pelvecalyceal nonvisualization was seen only with GFR values below 20 ml/min. The sign was 100% sensitive and 100% specific predicting GFR less than 20 and serum creatinine above 2.9 mg/dl. In vitro studies revealed markedly reduced amounts of DTPA chelate in the urine of patients with GFR less than 20, but in addition they had decreased tubular water reabsorption leading to dilution of the already reduced urine chelate contents. The reduced amounts of 99mTc-DTPA per ml of pelvocalyceal urine may account for the nonvisualization of this system. It may be that the intensity of the pelvocalyceal system reflects the adequacy of both the GFR, and the water reabsorptive function of the renal tubules.

Adult↗