Integrated versus separate reading of F-18 FDG-PET/CT and MRI for abdominal malignancies – effect on staging outcomes and diagnostic confidence
Abdominal cancer patients increasingly undergo multimodality imaging. This study evaluates effects of integrated reading of PET/CT and abdominal MRI on staging outcomes and diagnostic confidence compared to “routine” separate reading.
In total, N = 201 patients who underwent abdominal MRI and whole-body F-18 FDG-PET/CT within 14 days were retrospectively analyzed. Original MRI and PET/CT reports were retrieved and reported findings translated into a 5-point confidence score (1 = definitely benign to 5 = definitely malignant) for 7 standardized regions (primary tumor/regional lymph nodes/distant lymph nodes/liver/lung/bone/peritoneum) per patient. Two-reader teams (radiologist + nuclear medicine physician) then performed integrated reading of the images using the same scoring system.
Integrated reading led to discrepant findings in 59 of 201 (29%) of patients, with potential clinical impact in 25 of 201 (12%). Equivocal scores decreased from 5.7% (PET/CT) and 5.4% (MRI) to 3.2% (p = 0.05 and p = 0.14). Compared to the original PET/CT reports, integrated reading led to increased diagnostic confidence in 8.9% versus decreased confidence in 6.6% (p = 0.26). Compared with the original MRI reports, an increase in confidence occurred in 9.6% versus a decrease in 6.9% (p = 0.18). The effect on diagnostic confidence was most pronounced in lymph nodes (p = 0.08 vs. MRI), cervical cancer (p = 0.03 vs. MRI), and recurrent disease staging (p = 0.06 vs. PET/CT).
Integrated PET/CT+MRI reading alters staging outcomes in a substantial proportion of cases with potential clinical impact in ± 1 out of 9 patients. It can also have a small positive effect on diagnostic confidence, particularly in lymph nodes and cervical cancer, and in post-treatment settings. These findings support further collaboration between radiology and nuclear medicine disciplines.
• Increasing numbers of patients undergo multimodality imaging consisting of both MRI and PET/CT for staging of abdominal malignancies.
• Integrated reading of FDG-PET/CT and abdominal MR images by a team, consisting of a radiologist and a nuclear medicine physician, can alter staging outcomes compared to separate reporting of the exams in a substantial proportion of cases and with potential clinical impact in ± 1 out of 9 patients.
• Integrated PET/CT+MRI reading can have a small positive effect on diagnostic confidence.
KeywordsPositron emission tomography computed tomography Magnetic resonance imaging Multimodal imaging Neoplasms
Body mass index
Clinical report form
Fluorodeoxyglucose (or 2-deoxy-2-[18F]fluoroglucose)
Field of view
Kilovolt (or 1 × 103 V)
Milliampere-second (or 1 × 10−3 ampere-second)
Megabecquerel (or 1 × 106 becquerel)
Millicurie (or 1 × 10−3 Ci)
Magnetic resonance imaging
Positron emission tomography
Positron emission tomography computed tomography (hybrid PET and CT acquisition)
Standardized uptake value
The authors state that this work has not received any funding.
Compliance with ethical standards
The scientific guarantor of this publication is Dr. Doenja Lambregts.
Conflict of interest
The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.
Statistics and biometry
Two of the authors have significant statistical expertise (KJ and SR).
Written informed consent was waived by the Institutional Review Board.
Institutional Review Board approval was obtained.
• Diagnostic or prognostic study
• Performed at one institution
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