An Evaluation of Technetium-99m Tin Colloid—Its Value in the Diagnosis of Renal Transplant Rejection

Abstract

The value of the Technetium-99m tin colloid (TTC) scan in the diagnosis of renal transplant rejection occurring more than 1 month following transplantation was assessed. To our knowledge, use of this agent has not previously been reported. Gamma camera imaging was performed on 15 occasions in 14 patients in whom plasma creatinine was rising and in three patients in whom renal function was stable. Both a qualitative and a quantitative assessment of images was made. The radioactivity recorded over the graft at 12-16 min post injection was expressed as a percentage of that recorded at 0-4 min. In the nine patients in whom graft perfusion was adequate to allow interpretation of the TTC scan and in whom rejection was diagnosed by biopsy (six cases) or on clinical grounds (three cases), the index ranged from 45 to 153%. In two patients the graft was poorly perfused and the accumulation of TTC was predictably low despite the presence of rejection. In the seven patients with either a stable creatinine or with rising creatinine not due to rejection, the index ranged from 5 to 43%. Previously reported studies have shown that sulphur colloids may be of value in diagnosing graft rejection. This study suggests that Tc99m tin colloid may be regarded as a suitable alternative scanning agent and that some simplification of data collection and analysis can be achieved.