Comparative scanning of thyroid nodules with technetium-99m pertechnetate and technetium-99m methoxyisobutylisonitrile

Abstract

Thyroid imaging was performed using technetium-99m methoxyisobutylisonitrile and technetium-99m pertechnetate in 58 patients. The 99mTc-pertechnetate scans showed a total of 77 nodules: 60 cold, 13 hot and 4 of normal activity. There was no 99mTc-MIBI accumulation in 46.4% of 99mTc-pertechnetate cold nodules; 27 (45%) of these nodules showed 99mTc-MIBI uptake with the same intensity as the surrounding normal tissue, and five (8.6%) became hot with 99mTc-MIBI. Of the 99mTc-pertechnetate hot nodules 11 (84.6%) could not be differentiated from the normal extranodular tissue on the 99mTc-MIBI scan. The histopathology of 34 surgically removed nodules proved that increased, normal or decreased 99mTc-MIBI accumulation is not specific for thyroid malignancy and that the 99mTc-MIBI uptake depends mainly on the viability of thyroid tissue.

The usefulness of 99mTc-SestaMIBI scan in the diagnostic evaluation of thyroid nodules with oncocytic cytology

“…The results obtained did not provide any evidence that in this particular subgroup of thyroid nodules MIBI scan could improve the sensitivity and specificity in the pre-surgical detection of malignant tumors. Our data are in keeping with previous studies (23,27) including a limited series of thyroid HC tumors (27). Independently from the benign or malignant histotype, in our study the large majority (78.5%) of true HCT displayed an MIBI-positive scan, while only a minority (40%) of thyroid lesions with OM were MIBIpositive.…”

“…Independently from the benign or malignant histotype, in our study the large majority (78.5%) of true HCT displayed an MIBI-positive scan, while only a minority (40%) of thyroid lesions with OM were MIBIpositive. This finding suggests a direct relationship between MIBI uptake and number/mass of oncocytes, which present high affinity and uptake for MIBI (23,27). This phenomenon is believed to be due to crowded mitochondria (corresponding to the eosinophilic cytoplasmatic granules) independently from malignancy.…”

“…MIBI has been reported to accumulate in benign and malignant lesions, such as lung, brain, parathyroid tumors and bone lesions (18 -21). Recently, a positive MIBI scan has been reported in different thyroid tumors (22)(23)(24)(25)(26)(27), but, when applied to unselected thyroid nodules, this procedure is not able to differentiate benign from malignant lesions (24,27). Interestingly, however, MIBI scan has been found to be more frequently positive in HCT when compared with other thyroid neoplasias (27); however the relevance of this observation in the diagnostic evaluation of thyroid nodules is unclear, due to the very limited number of cases reported.…”

Dilemma in diagnosing thyroid adenoma – A case report

“…In such cases where FNA is insufficient there is a need for MIBI scintigraphy for the pre operative work up. In previous studies (11,12) it has been suggested that MIBI is not specific for thyroid malignancy.…”

“…Malignant cells in particular maintain a more negative mitochondria trans membrane potential, which in turn encourages increased MIBI accumulation because of their increased metabolic need (14). Benign lesions demonstrated various uptake behavior resulting in 23% of benign nodules being MIBI positive (11,12).…”