RT Journal Article SR Electronic T1 Direct Comparison of 18F-FDG PET and PET/CT in Patients with Colorectal Carcinoma JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1797 OP 1803 VO 44 IS 11 A1 Christian Cohade A1 Medhat Osman A1 Jeffrey Leal A1 Richard L. Wahl YR 2003 UL http://jnm.snmjournals.org/content/44/11/1797.abstract AB The purpose of this study was to compare 18F-FDG PET and PET/CT in a population of patients with colorectal cancer. Methods: PET and PET/CT images from 45 patients (17 women, 28 men; mean age ± SD, 60.8 ± 11.1 y) with known colorectal cancer referred for PET from June to November 2001 were retrospectively reviewed. Images were acquired with a PET/CT scanner, and 68Ge attenuation correction was applied. PET images and fused 68Ge attenuation–corrected PET and CT images were independently and separately interpreted by a moderately experienced reader unaware of the clinical information. Certainty of lesion characterization was scored on a 5-point scale (0 = definitely benign, 1 = probably benign, 2 = equivocal, 3 = probably malignant, 4 = definitely malignant). Lesion location was scored on a 3-point scale (0 = uncertain, 1 = probable, 2 = definite). The presence or absence of tumor was subsequently assessed using all available clinical, pathologic, and follow-up information. Analysis was provided for lesions detected by both PET and PET/CT. Results: The frequency of equivocal and probable lesion characterization was reduced by 50% (50 to 25) with PET/CT, in comparison with PET. The frequency of definite lesion characterization was increased by 30% (84 to 109) with PET/CT. The number of definite locations was increased by 25% (92 to 115) with PET/CT. Overall correct staging increased from 78% to 89% with PET/CT on a patient-by-patient analysis. Conclusion: PET/CT imaging increases the accuracy and certainty of locating lesions in colorectal cancer. More definitely normal and definitely abnormal lesions (and fewer probable and equivocal lesions) were identified with PET/CT than with PET alone. Staging and restaging accuracy improved from 78% to 89%.