Observational Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Radiol. Mar 28, 2016; 8(3): 322-330
Published online Mar 28, 2016. doi: 10.4329/wjr.v8.i3.322
Simultaneous whole body 18F-fluorodeoxyglucose positron emission tomography magnetic resonance imaging for evaluation of pediatric cancer: Preliminary experience and comparison with 18F-fluorodeoxyglucose positron emission tomography computed tomography
Brian S Pugmire, Alexander R Guimaraes, Ruth Lim, Alison M Friedmann, Mary Huang, David Ebb, Howard Weinstein, Onofrio A Catalano, Umar Mahmood, Ciprian Catana, Michael S Gee
Brian S Pugmire, Department of Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, United States
Alexander R Guimaraes, Division of Body Imaging, Oregon Health Sciences University, Portland, OR 97239, United States
Alexander R Guimaraes, Onofrio A Catalano, Michael S Gee, Division of Abdominal Imaging, Massachusetts General Hospital, Boston, MA 02114, United States
Alexander R Guimaraes, Umar Mahmood, Ciprian Catana, Martinos Center for Biomedical Imaging, Charlestown, MA 02129, United States
Ruth Lim, Umar Mahmood, Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, MA 02114, United States
Ruth Lim, Michael S Gee, Division of Pediatric Imaging, MassGeneral Hospital for Children, Boston, MA 02114, United States
Alison M Friedmann, Mary Huang, David Ebb, Howard Weinstein, Division of Pediatric Hematology-Oncology, MassGeneral Hospital for Children, Boston, MA 02114, United States
Author contributions: Gee MS was the principal investigator and designed the study; Pugmire BS and Gee MS participated in the acquisition, analysis, and interpretation of the data, and drafted the initial manuscript; Guimaraes AR, Lim R, Catalano OA, Mahmood U and Catana C were involved in revising the intellectual content of the data; Friedmann AM, Huang M, Ebb D, Weinstein H participated in patient recruitment.
Institutional review board statement: This study was reviewed and approved by the Dana Farber Cancer Institute Institutional Review Board.
Informed consent statement: All study participants, or their legal guardian, provided informed written consent prior to study enrollment.
Conflict-of-interest statement: The authors have no relevant financial interests to disclose.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Michael S Gee, MD, Division of Pediatric Imaging, MassGeneral Hospital for Children, 55 Fruit St, Boston, MA 02114, United States. msgee@partners.org
Telephone: +1-61-77244207 Fax: +1-61-77268360
Received: September 30, 2015
Peer-review started: October 1, 2015
First decision: November 4, 2015
Revised: November 18, 2015
Accepted: January 5, 2016
Article in press: January 7, 2016
Published online: March 28, 2016
Processing time: 173 Days and 23.2 Hours
Abstract

AIM: To describe our preliminary experience with simultaneous whole body 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography and magnetic resonance imaging (PET-MRI) in the evaluation of pediatric oncology patients.

METHODS: This prospective, observational, single-center study was Health Insurance Portability and Accountability Act-compliant, and institutional review board approved. To be eligible, a patient was required to: (1) have a known or suspected cancer diagnosis; (2) be under the care of a pediatric hematologist/oncologist; and (3) be scheduled for clinically indicated 18F-FDG positron emission tomography-computed tomography (PET-CT) examination at our institution. Patients underwent PET-CT followed by PET-MRI on the same day. PET-CT examinations were performed using standard department protocols. PET-MRI studies were acquired with an integrated 3 Tesla PET-MRI scanner using whole body T1 Dixon, T2 HASTE, EPI diffusion-weighted imaging (DWI) and STIR sequences. No additional radiotracer was given for the PET-MRI examination. Both PET-CT and PET-MRI examinations were reviewed by consensus by two study personnel. Test performance characteristics of PET-MRI, for the detection of malignant lesions, including FDG maximum standardized uptake value (SUVmax) and minimum apparent diffusion coefficient (ADCmin), were calculated on a per lesion basis using PET-CT as a reference standard.

RESULTS: A total of 10 whole body PET-MRI exams were performed in 7 pediatric oncology patients. The mean patient age was 16.1 years (range 12-19 years) including 6 males and 1 female. A total of 20 malignant and 21 benign lesions were identified on PET-CT. PET-MRI SUVmax had excellent correlation with PET-CT SUVmax for both benign and malignant lesions (R = 0.93). PET-MRI SUVmax > 2.5 had 100% accuracy for discriminating benign from malignant lesions using PET-CT reference. Whole body DWI was also evaluated: the mean ADCmin of malignant lesions (780.2 + 326.6) was significantly lower than that of benign lesions (1246.2 + 417.3; P = 0.0003; Student’s t test). A range of ADCmin thresholds for malignancy were evaluated, from 0.5-1.5 × 10-3 mm2/s. The 1.0 × 10-3 ADCmin threshold performed best compared with PET-CT reference (68.3% accuracy). However, the accuracy of PET-MRI SUVmax was significantly better than ADCmin for detecting malignant lesions compared with PET-CT reference (P < 0.0001; two-tailed McNemar’s test).

CONCLUSION: These results suggest a clinical role for simultaneous whole body PET-MRI in evaluating pediatric cancer patients.

Keywords: Positron emission tomography; Radiology; Pediatric imaging; Oncology; Cancer; Magnetic resonance imaging

Core tip: Combined positron emission tomography and magnetic resonance imaging (PET-MRI) is an exciting new imaging modality; however, its clinical role remains undefined. PET-MRI has distinct potential advantages for pediatric patients, but the data regarding PET-MRI in children remains limited. We report our experience using PET-MRI in pediatric oncology patients. We found excellent correlation between PET-MRI and PET-computed tomography (CT) maximum standardized uptake values as well as excellent test performance characteristics for PET-MRI using PET-CT as a reference. We also include an evaluation of MRI diffusion weighted imaging in comparison to PET-MRI and PET-CT, which has not been reported previously in the literature.