Image fusion of thallium-201 SPECT and MR imaging for the assessment of recurrent head and neck tumors following flap reconstructive surgery.

The aim of this study was to assess the value of fused MR and Tl-201 single photon emission computed tomography (SPECT) images in the diagnosis of recurrent head and neck tumors in patients after flap reconstruction surgery. Twenty-four patients after resection of primary head and neck tumors with flap reconstruction were suspected of having recurrent tumor by follow-up MR examination. Both MR examination and Tl-201 SPECT were prospectively performed to produce fused images. For qualitative analysis, two independent readers separately evaluated the existence of tumor recurrence in the fused images. The Tl-201 uptake of the lesion (Tl index) was also quantitatively compared with that of the normal nuchal muscles. Eighteen patients were histologically proved as having recurrence. The remaining 6 patients, false positive on MRI alone, had non-recurrence. Using the fused images, false positive was found in 1 case for one reader and 2 cases for the other reader. The Tl index of recurrent tumors was significantly higher (p < 0.001) than that of non-recurrent mass lesions. In the assessment of recurrent tumors following flap reconstruction surgery in the head and neck, the use of fused MRI and Tl-201 SPECT images can reduce the number of false positives.