Integrated versus separate reading of F-18 FDG-PET/CT and MRI for abdominal malignancies – effect on staging outcomes and diagnostic confidence

Abstract

ObjectiveAbdominal 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.MethodsIn total, N\u2009=\u2009201 patients who underwent abdominal MRI and whole-body F-18 FDG-PET/CT within 14\xa0days were retrospectively analyzed. Original MRI and PET/CT reports were retrieved and reported findings translated into a 5-point confidence score (1\u2009=\u2009definitely benign to 5\u2009=\u2009definitely 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.ResultsIntegrated 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\u2009=\u20090.05 and p\u2009=\u20090.14). Compared to the original PET/CT reports, integrated reading led to increased diagnostic confidence in 8.9% versus decreased confidence in 6.6% (p\u2009=\u20090.26). Compared with the original MRI reports, an increase in confidence occurred in 9.6% versus a decrease in 6.9% (p\u2009=\u20090.18). The effect on diagnostic confidence was most pronounced in lymph nodes (p\u2009=\u20090.08 vs. MRI), cervical cancer (p\u2009=\u20090.03 vs. MRI), and recurrent disease staging (p\u2009=\u20090.06 vs. PET/CT).ConclusionsIntegrated PET/CT+MRI reading alters staging outcomes in a substantial proportion of cases with potential clinical impact in ±\u20091 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.Key Points• 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 ±\u20091 out of 9 patients.• Integrated PET/CT+MRI reading can have a small positive effect on diagnostic confidence.