title: In Thyroidectomized Thyroid Cancer Patients, False-Positive I-131 Whole Body Scans Are Often Caused by Inflammation Rather Than Thyroid Cancer.
abstract: Objective. To show that I-131 false-positive results on whole-body scans (WBSs) after thyroidectomy for thyroid cancer may be a result of inflammation unassociated with the cancer. Methods. We performed a retrospective image analysis of our database of thyroid cancer patients who underwent WBS from January 2008 to January 2012 to identify and stratify false positives. Results. A total of 564 patients underwent WBS during the study period; 96 patients were referred for 99 I-131 single-photon emission computed tomography (SPECT/CT) scans to better interpret cryptic findings. Among them, 73 scans were shown to be falsely positive; 40/73 or 54.7% of false-positive findings were a result of inflammation. Of the findings, 17 were in the head, 1 in the neck, 4 in the chest, 3 in the abdomen, and 14 in the pelvis; 1 had a knee abscess. Conclusions. In our series, inflammation caused the majority of false-positive WBSs. I-131 SPECT/CT is powerful in the differentiation of inflammation from thyroid cancer. By excluding metastatic disease, one can properly prognosticate outcome and avoid unnecessary, potentially harmful treatment of patients with thyroid cancer.
authors.affiliation: NYU Langone Medical Center, NY, USA.
authors.forename: Yana Basis
authors.initials: YB
authors.lastname: Garger
authors.affiliation: NYU Langone Medical Center, NY, USA.
authors.forename: Mathew
authors.initials: M
authors.lastname: Winfeld
authors.affiliation: NYU Langone Medical Center, NY, USA.
authors.forename: Kent
authors.initials: K
authors.lastname: Friedman
authors.affiliation: NYU Langone Medical Center, NY, USA.
authors.forename: Manfred
authors.initials: M
authors.lastname: Blum
keywords: 131-iodine; PTC; WBS; false positive; inflammation; papillary thyroid cancer; thyroid cancer; whole body scan