TY - JOUR T1 - <sup>68</sup>Ga-DOTATOC PET/CT of Neuroendocrine Tumors: Spotlight on the CT Phases of a Triple-Phase Protocol JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 697 LP - 704 DO - 10.2967/jnumed.110.083741 VL - 52 IS - 5 AU - Juri Ruf AU - Jan Schiefer AU - Christian Furth AU - Ortud Kosiek AU - Siegfried Kropf AU - Friederike Heuck AU - Timm Denecke AU - Marianne Pavel AU - Andreas Pascher AU - Bertram Wiedenmann AU - Holger Amthauer Y1 - 2011/05/01 UR - http://jnm.snmjournals.org/content/52/5/697.abstract N2 - The diagnostic value of neuroendocrine tumor (NET) imaging using PET with integrated CT is dependent on both components. This retrospective study assessed the value of the single CT phases of a triple-phase (early arterial, portal-venous inflow, and venous) CT protocol in comparison to 68Ga-DOTATOC PET in a masked reading. Methods: 68Ga-DOTATOC PET/CT examinations from 51 patients with known or suspected NET were included. Two readers assessed the data of PET and each of the 3 CT phases for NET lesions independently (using a 3-point score: 1 = benign, 2 = indeterminate, and 3 = malignant) and by consensus (using binary benign/malignant interpretation only). Only lesions within the field of the abdominal scan were evaluated. Clinical and imaging follow-up, histopathology (if available), and the decision of an interdisciplinary truth-panel served as a standard of reference. In addition to the calculation of standard statistical parameters (including general linear mixed models), interobserver reliability was estimated (Cohen's κ). Results: Of 510 abdominal lesions observed, 354 were classified as malignant. Sensitivity was 77.1% for combined triple-phase CT, 53.4% for arterial CT, 66.1% for portal-venous CT, 66.9% for venous CT, and 72.8% for PET. The respective specificities were 85.3%, 92.9%, 92.3%, 89.7%, and 97.4%, and the respective accuracies were 79.6%, 65.5%, 74.1%, 73.9%, and 80.4%. Although arterial CT was found to be inferior to PET, portal-venous CT, and venous CT (P &lt; 0.001), the differences between the other scans were not significant. Detection was exclusively by PET for 16.1% of lesions, by triple-phase CT for 20.3%, by arterial CT for 0.5%, by portal-venous CT for 3.9%, and by venous CT for 3.9%. Regarding interobserver reliability, the κ-value was 0.768 for PET, 0.391 for triple-phase CT, 0.577 for arterial CT, 0.583 for portal-venous CT, and 0.482 for venous CT. Conclusion: No CT phase can be omitted in NET imaging, and the triple-phase protocol continues to be strongly recommended also for PET/CT. ER -