PET-CT as an effective imaging modality in the staging and follow-up of post-transplant lymphoproliferative disorder following solid organ transplantation

Noraini AR, Gay E, Ferrara C, Ravelli E, Mancini V, Morra E, Muti P, Tahir A, Abdul Jalil N, Rossetti C
Correspondence: Dr Noraini Abdul Rahim, norainichoo2@hotmail.com

ABSTRACT
Introduction To establish the role of positron-emission tomography (PET)-computed tomography (CT) in post-transplant lymphoproliferative disorder (PTLD) patients, compared to conventional imaging (ultrasonography/CT/magnetic resonance imaging) in relation to its accuracy, sensitivity and specificity.
Methods 30 patients (26 males and 4 females), with a median age of 49.5 (range 18–74) years, were retrospectively evaluated. In 29 cases, the diagnosis was confirmed by histopathology. Malignant lymphoma was detected in 20 cases, polymorphic lymphoproliferative disorder in six cases, multiple myeloma in two cases and Hodgkin’s disease in one case. A total of 49 PET-CTs (13 studies for staging at diagnosis and 36 studies at follow-up as assessment post-therapy) were compared to conventional imaging. Imaging results in accordance with disease status were assessed at a median follow-up of 17.8 (range 1.5–42.2) months post-PET-CT. 
Results In 41 of 49 examinations performed for staging and on follow-up, PET-CT and conventional imaging findings were concordant. Compared to conventional imaging, PET-CT showed comparable sensitivity (75 percent vs. 83 percent), similar specificity (100 percent in both modalities) and comparable accuracy (77 percent vs. 85 percent) during staging at diagnosis. PET-CT was found to be superior to conventional imaging modalities at follow-up, with greater sensitivity (100 percent vs. 81 percent), specificity (80 percent vs. 100 percent) and accuracy (97 percent vs. 83 percent). 
Conclusion PET-CT is an accurate diagnostic tool for staging and for the follow-up of PTLD patients. It represents a good alternative imaging method to avoid contrast-related nephrotoxicity in patients who often develop impaired renal function secondary to chronic immunosuppressive therapy. However, further studies are recommended before considering PET-CT as a routine diagnostic tool in PTLD.