99mTc MAG3 scintigraphy in a patient with hyperacute antibody mediated Rejection: A description of the correlation between image findings and clinical disease process.

Abstract

BackgroundHyperacute antibody mediated rejection (HA-AMR) occurs within 24 h after a renal transplant. Technetium-99m Mercaproacetyl triglicine (99mMAG3) scintigraphy is rarely done within this time period and clinicians rely on clinical features and laboratory parameters for diagnosis. To date literature reports on the correlation between clinical features, laboratory parameters and 99mTc MAG3 scintigraphy in patients with HA-AMR is sparce. AimDescribe the scintigraphic features on serial 99mMAG3 renograms together with the clinical and laboratory findings at diagnosis and during treatment of a patient with HA-AMR. MethodFour 99mTc MAG3 renograms performed on days 1, 4, 11 and 66 post transplant were reviewed. Clinical and laboratory parameters (serum creatinine and urine output) were also evaluated during these time points. ResultsPatient was transplanted at 11 a.m. Overnight patient was clinically well, urine output was 5500 mL and creatinine decreased from 866 μmol/L to 795 μmol/L. 99mTc MAG3 renogram however showed markedly delayed and decreased perfusion with poor uptake and cortical defects. Renogram grade (RG),as described by Heaf et al., was 4. Patient was taken back to theatre to exclude vascular pathology. No thrombus was found, however infarcted areas on the surface of the kidney were seen. Patient was commenced on treatment for HA-AMR. On day 4 post transplant and day 3 after initiation of antirejection therapy, urine output decreased to 850 mL/d and creatinine increased to 955 μmol/L. Another 99mTc MAG3 renogram was performed which showed improved perfusion and uptake as well as significant improvement in the cortical defects. On day 11 post transplant the patients creatinine decreased to 635 μmol/L and urine output increased to 1030 mL/d. 99mTc MAG3 renogram showed a further improvement in perfusion, uptake and cortical defects. The patient was discharged on day 15 post transplant with a creatinine of 425 μmol/L. She continued to do well and on day 66 post transplant her creatinine was 246 μmol/L. 99mTc MAG3 renogram at this stage also showed a further improvement in perfusion, uptake and cortical defects. Renogram grade at discharge was 1. Conclusion99mTc MAG3 scintigraphy is recommended for baseline renal function within 24 h after renal transplant. Clinical parameters may take several days before they a representative of an underlying pathological process. 99mTc MAG3 scintigraphic features correlate with underlying disease process and outcome.