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FIGURE 7. Anatomic localization of ectopic parathyroid adenoma by combined 99mTc-sestamibi and 99mTc-albumin SPECT. (Top left) Tomographic coronal slice obtained after 99mTc-sestamibi administration demonstrates focal area of abnormal tracer uptake in mediastinum, whose exact anatomic location with respect to other mediastinal structures remains uncertain. (Top right) Dose of 99mTc-albumin was then injected (without moving patient) as indicator of intravascular space, and another SPECT image was acquired under same conditions as 99mTc-sestamibi SPECT. (Bottom) Image fusion of corresponding coronal slices demonstrates that lesion with focal uptake of 99mTc-sestamibi is located in aorto-pulmonary window. Subsequent radioguided surgery confirmed presence of parathyroid adenoma in anatomic location identified by fusion analysis.
