title: Scintigraphic pitfalls in giant parathyroid glands.
abstract: We report a case of hyperparathyroidism with surgically confirmed bilaterally enlarged parathyroid glands mimicking a normal thyroid gland. Technetium-99m-pertechnetate-201Tl chloride subtraction scintigraphy was inconclusive because of suppressed thyroidal [99mTc]pertechnetate uptake after coronary angiography. Technetium-99m-sestamibi double-phase scintigraphy showed homogeneous 99mTc-sestamibi uptake that mimicked a normal thyroid gland and no differential washout, thus leading to an erroneous visual interpretation of a normal scan. Semiquantitative assessment of tracer washout, however, can differentiate between normal thyroid tissue and symmetrical parathyroid uptake mimicking normal thyroid tissue. We conclude that semiquantitative assessment of tracer washout increases the diagnostic sensitivity of 99mTc-sestamibi double-phase scintigraphy if: (a) the interpreter is unaware of the anatomical situation, (b) the scintigraphic delineation of the thyroid is hampered by a blocked tracer uptake or (c) the visual interpretation reveals no differential washout in the neck region.
authors.affiliation: Clinic of Nuclear Medicine, University of Vienna, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Staudenherz
authors.forename: D
authors.initials: D
authors.lastname: Telfeyan
authors.forename: E
authors.initials: E
authors.lastname: Steiner
authors.forename: B
authors.initials: B
authors.lastname: Niederle
authors.forename: T
authors.initials: T
authors.lastname: Leitha
authors.forename: K
authors.initials: K
authors.lastname: Kletter
mesh_terms: D000368:Aged; D006801:Humans; D006961:Hyperparathyroidism / Q000000981:diagnostic imaging*; D008297:Male; D010280:Parathyroid Glands / Q000000981:diagnostic imaging; D011877:Radionuclide Imaging; D013382:Subtraction Technique; D017256:Technetium Tc 99m Sestamibi; D013794:Thallium Radioisotopes
chemical_list: D013794:Thallium Radioisotopes; D017256:Technetium Tc 99m Sestamibi