Is there Incremental Value of SPECT/CT over Planar Imaging in the Assessment of Nodular Goiter by Tc-99m-Pertechnetate Scintigraphy?

Objectives The purpose of our investigation was to compare hybrid SPECT/CT and planar imaging of Tc-99m-pertechnetate (Tc-99m-TcO₄) uptake in nodular and partially retrosternal goiter with regard to the number of focal lesions detected and lobe length.

Methods Retrospective analysis of our SPECT/CT database identified twenty patients in whom SPECT/CT of the thyroid gland had been performed on a Symbia T6 (Siemens, Hoffman Estates, IL, USA) in addition to planar scintigraphy 20 minutes p.i. of 50 MBq Tc-99m-pertechnetate. Planar images and SPECT/CT were analysed with regard to the number of focal lesions and to the length of the thyroid lobes. Both image datasets were evaluated separately, but with access to ultrasound findings.

Results Thirty-eight thyroid lobes of 20 patients were analysed, two patients had had hemithyroidectomy. In 11 lobes multiple nodules and in 27 lobes one to three thyroid nodules were identified by ultrasound imaging. Planar imaging found 32, SPECT/CT 45 focal abnormalities of Tc-99m-TcO₄ uptake. Lobe length was 5.2 (+/- 2.2) cm on planar images, and 5.4 (+/- 2.8) cm in SPECT/CT.

Conclusions SPECTCT was superior to planar imaging in detecting focal abnormalities of Tc-99m-TcO₄ uptake. This encourages studies of the possible clinical role of Tc-99m-TcO₄-SPECT/CT in nodular goiter with retrosternal extension.