Can renal scan findings predict biopsy-proven allograft rejection?

To assess the usefulness of isotopic renogram in diagnosing acute renal graft rejection.

Degree of perfusion and allograft uptake of tracer were correlated with the clinical and biopsy diagnoses in 15 postrenal transplant patients with varying degrees of renal impairment. Renographic findings and perfusion calculations were done by a blinded observer.

A strong correlation was found between renal histology and renal scan findings in 13 of 15 patients. Sensitivity and specificity of renal scanning in diagnosing acute rejection were 85% and 50% respectively (using renal biopsy findings as the gold standard).

Our results demonstrate a strong correlation between blinded perfusion assessment and biopsy-proven acute rejection. We conclude, therefore, that single renal flow scan with DTPA (noninvasive/nonnephrotoxic) allows a physician to tailor therapy for acute renal graft dysfunction. We suggest that in cases with a renographic diagnosis of AR, the patient should receive standard antirejection therapy. Renal biopsy should be reserved for those instances when the renographic findings are not definitive and those when the patient fails to respond to a standard methylprednisolone therapy.