Diagnostic role of whole-body [18F]-FDG positron emission tomography in patients with symptoms suspicious for malignancy after heart transplantation.

BACKGROUND

Increased rates of malignancies and infections occur in transplant patients under immunosuppression, but the resultant clinical symptoms, and results of physical examination, chest X-ray, abdominal ultrasonography and laboratory findings are frequently difficult to interpret or inconclusive. The aim of the present study was to investigate the usefulness of whole-body [(18)F]-FDG PET for investigation of heart transplant patients suffering from suspicious symptoms, with a previously ambiguous diagnosis.

METHODS

Seventeen consecutive patients (8 women; 48 ± 22 years) with non-specific symptoms (lymphadenopathy, fever of unknown origin or recurrent febrile temperatures, weight loss, abdominal pain, night sweating, cough or generally reduced physical condition) were evaluated retrospectively. All patients underwent whole-body [(18)F]-FDG examinations by PET (7 patients) or PET/CT (10 patients) at 8 ± 6 (range 0.1 to 21) years after orthotopic heart transplantation (OHT). During a follow-up of 28 ± 25 months, results of bone marrow biopsies, and histologic and/or microbiologic findings were registered and retrospectively compared with the PET results.

RESULTS

PET revealed the cause of non-specific symptoms in 9 of 17 patients; there were 5 cases of lymphoproliferative disease (PTLD), 2 carcinomas and 2 cases of infection. Four patients were rated false positive, 1 patient false negative and 3 patients were correctly rated as negative. Sensitivity, specificity and positive and negative predictive values were 0.90, 0.43, 0.69 and 0.75, respectively, giving an overall diagnostic accuracy of 0.71.

CONCLUSIONS

A non-invasive strategy of using whole-body [(18)F]-FDG PET or PET/CT in heart transplant recipients with non-specific unexplained symptoms may offer diagnostic stratification for malignancy and infections with a high sensitivity and modest diagnostic accuracy. These findings require prospective confirmation.