Assessment of Suspected Malignancy or Infection in Immunocompromised Patients After Solid Organ Transplantation by [18F]FDG PET/CT and [18F]FDG PET/MRI

Nika Guberina; Anja Gäckler; Johannes Grueneisen; Axel Wetter; Oliver Witzke; Ken Herrmann; Christoph Rischpler; Wolfgang Fendler; Lale Umutlu; Lino Morris Sawicki; Michael Forsting; Hana Rohn

doi:10.1007/s13139-020-00648-5

Assessment of Suspected Malignancy or Infection in Immunocompromised Patients After Solid Organ Transplantation by [¹⁸F]FDG PET/CT and [¹⁸F]FDG PET/MRI

Nucl Med Mol Imaging. 2020 Aug;54(4):183-191. doi: 10.1007/s13139-020-00648-5. Epub 2020 Jul 2.

Authors

Nika Guberina^{1

2}, Anja Gäckler³, Johannes Grueneisen², Axel Wetter², Oliver Witzke⁴, Ken Herrmann^{5

6}, Christoph Rischpler⁵, Wolfgang Fendler⁵, Lale Umutlu², Lino Morris Sawicki⁷, Michael Forsting², Hana Rohn⁴

Affiliations

¹ Department of Radiotherapy, University of Duisburg-Essen, University Hospital Essen, Hufelandstraße 55, 45147 Essen, Germany.
² Department of Diagnostic and Interventional Radiology and Neuroradiology, University of Duisburg-Essen, University Hospital Essen, Essen, Germany.
³ Department of Nephrology, University of Duisburg-Essen, University Hospital Essen, Essen, Germany.
⁴ Department of Infectious Diseases, University of Duisburg-Essen, University Hospital Essen, Essen, Germany.
⁵ Department of Nuclear Medicine, University of Duisburg-Essen, University Hospital Essen, Essen, Germany.
⁶ German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany.
⁷ Department of Diagnostic and Interventional Radiology, University Hospital Düsseldorf, Düsseldorf, Germany.

Abstract

Purpose: To study the value of 2-deoxy-2-[¹⁸F]fluoro-D-glucose([¹⁸F]FDG) positron emission tomography/computed tomography (PET/CT) and [¹⁸F]FDG positron emission tomography/magnetic resonance imaging (PET/MRI) in assessing immunocompromised patients with suspected malignancy or infection.

Methods: [¹⁸F]FDG-PET/CT and [¹⁸F]FDG-PET/MRI examinations of patients who were immunocompromised after receiving lung, heart, pancreas, kidney, liver, or combined kidney-liver transplants were analyzed in this retrospective study. Patients underwent whole-body hybrid-imaging because of clinical signs of malignancy and/or infection. Findings were assessed by molecular features ([¹⁸F]FDG-uptake) and morphological changes. The final diagnosis, which was arrived at after review of clinical, laboratory, and histopathologic analyses and follow-up imaging studies, served as the reference standard.

Results: Altogether, (i) 28 contrast-enhanced [¹⁸F]FDG-PET/CT scans (CE-PET/CT), (ii) 33 non-contrast [¹⁸F]FDG-PET/CT scans (NC-PET/CT), and (iii) 18 [¹⁸F]FDG-PET/MRI scans were included. Additionally, 12/62 patients underwent follow-up PET imaging to rule out vital tumor or metabolic active inflammatory processes. CE-PET/CT exhibited 94.4% sensitivity, 80.0% specificity, 89.5% positive predictive value (PPV), 88.9% negative predictive value (NPV), and 89.3% accuracy with regard to the reference standard. NC-PET/CT exhibited 91.3% sensitivity, 80.0% specificity, 91.3% PPV, 80.0% NPV, and 87.9% accuracy. PET/MRI exhibited 88.6% sensitivity, 99.2% specificity, 99.6% PPV, 81.3% NPV, and 94.4% accuracy. Exact McNemar statistical test (one-sided) showed significant difference between the CT-/MR-component alone and the integrated PET/CT and PET/MRI for diagnosis of malignancy or infection (p value < 0.001). Radiation exposure was 4- to 7-fold higher with PET/CT than with PET/MRI.

Conclusion: For immunocompromised patients with clinically unresolved symptoms, to rule out vital tumor manifestations or metabolic active inflammation, [¹⁸F]FDG-PET/MRI, CE-[¹⁸F]FDG-PET/CT, and NC-[¹⁸F]FDG-PET/CT exhibit excellent performance in diagnosing malignancy or infection. The main strength of PET/MRI is its considerably lower level of radiation exposure than that associated with PET/CT.

Keywords: Diagnostic imaging; Magnetic resonance imaging; Positron emission tomography; Transplant immunology.