@article {Gollub1583, author = {Marc J. Gollub and Richard Hong and Debra M. Sarasohn and Tim Akhurst}, title = {Limitations of CT During PET/CT}, volume = {48}, number = {10}, pages = {1583--1591}, year = {2007}, doi = {10.2967/jnumed.107.043109}, publisher = {Society of Nuclear Medicine}, abstract = {Our aim was to determine the diagnostic limitations of low-dose, unenhanced CT scans performed for anatomic reference and attenuation correction during PET/CT. Methods: The Radiology Information System at our oncologic hospital was queried during the 9-mo period from July 2002 to April 2003 for patients with PET/CT scans and diagnostic enhanced CT within 2 wk of each other. One radiologist interpreted the CT portion of the PET/CT (CTp) unaware of the PET results and the associated enhanced diagnostic CT (CTd). A medical student compared this interpretation with the official report of the CTd and listed all discrepancies between reports. A separate radiologist compared CTp and CTd images and classified true discrepant findings as due to lack of intravenous contrast, arm-position artifact, lack of enteric contrast, low milliamperage (mA), and quality of lung images. Results: Among 100 patients, the most common malignancies were lymphoma (n = 37), cancer of the colorectum (n = 31), and esophageal cancer (n = 15). Among 194 true discrepancies in which findings were missed at CTp, causes were as follows: (a) lack of intravenous contrast (128/194, 66\%), (b) arm-down artifact (17/194, 9\%), (c) quality of lung images (26/194, 13\%), (d) lack of enteric contrast (15/194, 8\%), and (e) low mA (8/194, 4\%). Discrepancies were seen most commonly in detecting lymphadenopathy and visceral metastases. Conclusion: Most missed findings on the unenhanced CT portion of the PET/CT scans were due to technical factors that could be altered. Discrepant findings would have led to altered management in only 2 patients, suggesting a role for limited repeat imaging to reduce radiation and use of valuable resources.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/48/10/1583}, eprint = {https://jnm.snmjournals.org/content/48/10/1583.full.pdf}, journal = {Journal of Nuclear Medicine} }