SPECT/CT imaging in children with papillary thyroid carcinoma
Pediatric Radiology, 06/07/2011
SPECT/CT precisely localizes neck iodine uptake. In small numbers of patients, treatment is affected. SPECT/CT should be used when available in thyroid carcinoma patients.
20 SPECT/CT and planar studies were reviewed in 13 children with papillary thyroid carcinoma after total thyroidectomy.
Seven studies used I–123 and 13 used I–131, after elevating TSH by T4 deprivation or intramuscular thyrotropin alfa.
Eight children had one study and five children had two to four studies.
Studies were performed at initial post–total thyroidectomy evaluation, follow–up and after I–131 treatment doses.
SPECT/CT was performed with a diagnostic–quality CT unit in 13 studies and a localization–only CT unit in 7.
Stimulated thyroglobulin was measured (except in 2 cases with anti–thyroglobulin antibodies).
In 13 studies, neck activity was present but poorly localized on planar imaging; all foci of uptake were precisely localized by SPECT/CT. Two additional foci of neck uptake were found on SPECT/CT.
SPECT/CT differentiated high neck uptake from facial activity.
In six studies (four children), neck uptake was identified as benign by SPECT/CT (three thyroglossal duct remnants, one skin contamination, two by precise anatomical CT localization).
In two children, SPECT/CT supported a decision not to treat with I–131.
When SPECT/CT was unable to identify focal uptake as benign, stimulated thyroglobulin measurements were valuable.
In three of 13 studies with neck uptake, SPECT/CT provided no useful additional information.