Context Deciding on the appropriate therapy for patients with malignant diseases
mandates accurate tumor staging with whole-body coverage. Magnetic resonance
imaging (MRI) and a combined modality including positron emission tomography
(PET) and computed tomography (CT) provide whole-body tumor staging in a single
Objective To determine the staging accuracies of both whole-body PET/CT and whole-body
MRI for different malignant diseases.
Design, Setting, and Patients Prospective, blinded, investigator-initiated study of 98 patients (mean
age, 58 years; range, 27-94 years) with various oncological diseases who underwent
back-to-back whole-body glucose analog [18F]-fluorodeoxyglucose–PET/CT
and whole-body MRI for tumor staging. The study was conducted at a university
hospital from December 2001 through October 2002 and had a mean follow-up
of 273 days (range, 75-515 days). The images were evaluated by 2 different,
blinded reader teams. The diagnostic accuracies of the 2 imaging procedures
Main Outcome Measures Correct classification of the primary tumor, regional lymph nodes, and
distant metastasis (overall TNM stage) using whole-body PET/CT and whole-body
MRI. Secondary outcome measures were accurate assessment of T-stage, N-stage,
and M-stage by the 2 imaging procedures.
Results Of 98 patients, the overall TNM stage was correctly determined in 75
with PET/CT (77%; 95% confidence interval [CI], 67%-85%) and in 53 with MRI
(54%; 95% CI, 44%-64%) (P<.001). Compared with
MRI, PET/CT had a direct impact on patient management in 12 patients. Results
from MRI changed the therapy regimen in 2 patients compared with PET/CT. Separate
assessment of T-stage (with pathological verification) in 46 patients revealed
PET/CT to be accurate in 37 (80%; 95% CI, 66%-91%) and MRI to be accurate
in 24 (52%; 95% CI, 37%-67%) (P<.001). Of 98 patients,
N-stage was correctly determined in 91 patients with PET/CT (93%; 95% CI,
86%-97%) and in 77 patients with MRI (79%; 95% CI, 69%-86%) (P = .001). Both imaging procedures showed a similar performance in
detecting distant metastases.
Conclusions The feasibility and diagnostic accuracy of the whole-body staging strategies
of PET/CT and MRI are established. Superior performance in overall TNM staging
suggests the use of [18F]-fluorodeoxyglucose–PET/CT as a possible first-line
modality for whole-body tumor staging.