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.

Methods

  • 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).

Results

  • 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.

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