Jan P Pennings1, Robbert J de Haas1, Kawthar J A Murshid1, Koert P de Jong2, Rudi A J O Dierckx1, Thomas C Kwee3. 1. Department of Radiology, Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands. 2. Department of Hepato-Pancreato-Biliary Surgery & Liver Transplantation, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands. 3. Department of Radiology, Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands. Electronic address: thomaskwee@gmail.com.
Abstract
INTRODUCTION: This study aimed to determine the positive predictive value (PPV) of positron emission tomography/computed tomography (PET/CT) with an 18F-fluoro-2-deoxy-D-glucose (FDG)-avid presacral lesion for locally recurrent rectal cancer, and the additional value of magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI). MATERIALS AND METHODS: This retrospective study included 38 patients who completed primary rectal cancer treatment and who presented with a suspicious FDG-avid presacral lesion on PET/CT. Twenty-seven patients also underwent MRI, of whom 24 with DWI. PPV of FDG-PET/CT and additional value of MRI, including DWI, for the diagnosis of recurrent presacral cancer were determined. RESULTS: The PPV of PET/CT with an FDG-avid presacral lesion for the diagnosis of locally recurrent rectal cancer was 58% (22/38). Air in the FDG-avid presacral lesion, as visible on the CT component of the PET/CT examination, favoured the diagnosis of benign presacral tissue with a sensitivity of 56.3% (9/16) and a specificity 81.8% (18/22). Areas under the receiver operating characteristic curve (AUCs) of MRI without DWI for the diagnosis of locally recurrent rectal cancer in FDG-avid presacral tissue were 0.765 and 0.840, for observers 1 and 2. AUCs of MRI with DWI were 0.803 and 0.811, for observers 1 and 2. There were no significant differences among any of these AUCs (P = 0.169 to 0.906). CONCLUSIONS: FDG-PET/CT has a poor PPV for locally recurrent rectal cancer in the presacral space. The observation of air in the FDG-avid presacral lesion and additional MRI assessment are diagnostically helpful, without a significant additional value of DWI.
INTRODUCTION: This study aimed to determine the positive predictive value (PPV) of positron emission tomography/computed tomography (PET/CT) with an 18F-fluoro-2-deoxy-D-glucose (FDG)-avid presacral lesion for locally recurrent rectal cancer, and the additional value of magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI). MATERIALS AND METHODS: This retrospective study included 38 patients who completed primary rectal cancer treatment and who presented with a suspicious FDG-avid presacral lesion on PET/CT. Twenty-seven patients also underwent MRI, of whom 24 with DWI. PPV of FDG-PET/CT and additional value of MRI, including DWI, for the diagnosis of recurrent presacral cancer were determined. RESULTS: The PPV of PET/CT with an FDG-avid presacral lesion for the diagnosis of locally recurrent rectal cancer was 58% (22/38). Air in the FDG-avid presacral lesion, as visible on the CT component of the PET/CT examination, favoured the diagnosis of benign presacral tissue with a sensitivity of 56.3% (9/16) and a specificity 81.8% (18/22). Areas under the receiver operating characteristic curve (AUCs) of MRI without DWI for the diagnosis of locally recurrent rectal cancer in FDG-avid presacral tissue were 0.765 and 0.840, for observers 1 and 2. AUCs of MRI with DWI were 0.803 and 0.811, for observers 1 and 2. There were no significant differences among any of these AUCs (P = 0.169 to 0.906). CONCLUSIONS:FDG-PET/CT has a poor PPV for locally recurrent rectal cancer in the presacral space. The observation of air in the FDG-avid presacral lesion and additional MRI assessment are diagnostically helpful, without a significant additional value of DWI.
Authors: Verena Plodeck; Ivan Platzek; Johannes Streitzig; Heiner Nebelung; Sophia Blum; Jens-Peter Kühn; Ralf-Thorsten Hoffmann; Michael Laniado; Enrico Michler; Sebastian Hoberück; Klaus Zöphel; Jörg Kotzerke; Johannes Fritzmann; Jürgen Weitz; Christoph G Radosa Journal: Abdom Radiol (NY) Date: 2021-08-17