technetium-tc-99m-tetrofosmin and Thyroid-Nodule

Topics: Diagnosis, Differential; Humans; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Sodium Pertechnetate Tc 99m; Technetium Tc 99m Sestamibi; Thyroid Gland; Thyroid Neoplasms; Thyroid Nodule; Ultrasonography

Radioisotope methods have shown to be useful in the non-invasive diagnosis of thyroid nodules over the past years. The present prospective study aims to evaluate the efficacy of gamma imaging using single and dual tracer using Tc-99m pertechnetate and Tc-99m tetrofosmin for evaluation and management of thyroid nodules.. Dynamic (perfusion) imaging was performed after injecting 148-185 MBq (4-5 mCi) of Tc-99m pertechnetate followed by static imaging. A second, dynamic (perfusion) imaging study within same week was performed with 296-370MBq (8-10mCi) of Tc-99m tetrofosmin on same group of patients followed by early and delayed images. Results of radionuclide perfusion scan from both studies were compared qualitatively with postsurgical histopathology or fine needle aspiration cytology (FNAC).. Total 65 nodules in 50 patients were included in the study. With single tracer, the specificity and accuracy of Tc-99m pertechnetate was 23% and 45% and for Tc-99m tetrofosmin scan was 40% and 49%. When dual tracers were evaluated for the same group of patients, the specificity was 56% and accuracy was 55%.. Dual Tracer technique with Tc-99m pertechnetate and Tc-99m tetrofosmin could be helpful in selecting nodules need surgical intervention. This technique can be used for convenient and rapid diagnostic evaluation of thyroid nodules non-invasively. We suggest a combination of fine needle aspiration biopsy and dual use of Tc-99m-pertechnetate and Tc-99m-tetrofosmin as a routine diagnostic approach to thyroid nodules.

Topics: Adolescent; Adult; Aged; Child; Diagnosis, Differential; Female; Humans; Male; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Prospective Studies; Radionuclide Imaging; Radiopharmaceuticals; Sodium Pertechnetate Tc 99m; Thyroid Gland; Thyroid Nodule; Young Adult

A study was undertaken to evaluate the diagnostic efficiency of Tc-Tetrofosmin scan and color Doppler in the characterization of benign and malignant solitary thyroid nodules.. Fifty-two patients found to have a cold solitary thyroid nodule on Tc-pertechnetate scintigraphy were included in this study. All patients underwent a single-injection dual-phase (30 min and 120 min) Tc-Tetrofosmin scan. The intranodular vascularity was measured using color Doppler sonography. Fine-needle aspiration cytology was performed on all the patients. In the following days and weeks all patients underwent surgery.. Thirteen out of 15 patients with thyroid cancer showed delayed retention of radiotracer (on 120 min images as compared to the initial 30 min image). Thirty-six out of 37 patients harboring benign solitary nodules showed significant washout of tracer on delayed images. Sensitivity, specificity, positive predictive value and negative predictive value of delayed Tc-Tetrofosmin scintigraphy were found to be 86.6, 97.2, 92.8 and 94.7%, respectively. The Doppler study was able to demonstrate increased vascularity in the center of 8 of the 15 malignant nodules. Thirty-two patients harboring a benign solitary nodule showed normal or increased peripheral vascularity on Doppler study. Sensitivity, specificity, positive predictive value and negative predictive value of color Doppler were found to be 53.5, 86.4, 61.5 and 82%, respectively.. Delayed Tc-Tetrofosmin scintigraphy is a highly sensitive and specific method for characterizing solitary thyroid nodules, while color Doppler has a low sensitivity but relatively high specificity in differentiating benign from malignant thyroid lesions.

Topics: Adolescent; Adult; Aged; Biopsy, Fine-Needle; Child; Diagnosis, Differential; Female; Humans; Male; Middle Aged; Neovascularization, Pathologic; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Thyroid Neoplasms; Thyroid Nodule; Ultrasonography, Doppler, Color

Various radionuclides, including 67Ga, 201Tl and 99Tcm-sestamibi, have been used to differentiate benign from malignant thyroid nodules. 99Tcm-tetrofosmin, a lipophilic cationic radiotracer, and 99Tcm-sestamibi have also been reported to accumulate in thyroid tumours. In this study, we evaluated the role of 99Tcm-tetrofosmin in the differentiation of malignant from benign thyroid nodules. Seventy-nine patients with solitary non-functioning thyroid nodules were included in the study. Fine-needle aspiration biopsy was performed in all patients. Sixty patients were subsequently operated on and 19 patients refused surgery. After the injection of 370 MBq 99Tcm-tetrofosmin, static images at 5, 30, 60, 120 and 180 min were acquired. Both visual and semi-quantitative analysis was performed. On visual interpretation, the nodules with late retention were classified as positive for malignancy and nodules without late retention were classified as negative for malignancy. In the semi-quantitative analysis, regions of interests were drawn over the nodule and contralateral normal thyroid tissue. The average number of counts was recorded and tumour-to-normal thyroid tissue ratios calculated. Post-operative histology revealed 19 malignant and 41 benign nodules. Of the benign nodules, adenomas behaved similarly to the malignant nodules with late retention of tracer, while adenomatous nodules revealed no late retention on delayed images and could be differentiated from malignant tumours. In the semi-quantitative analysis, there was a significant difference in tumour-to-normal tissue ratios for adenomatous nodules and malignant tumours as well as adenomas. We conclude that it is not possible to differentiate between malignant and benign thyroid nodules with 99Tcm-tetrofosmin. However, 99Tcm-tetrofosmin scintigraphy is helpful in selecting nodules that can be cured by surgical intervention.

Topics: Adenoma; Adolescent; Adult; Aged; Carcinoma; Diagnosis, Differential; Female; Humans; Male; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Thyroid Neoplasms; Thyroid Nodule

Topics: Goiter, Nodular; Humans; Organophosphorus Compounds; Organotechnetium Compounds; Preoperative Care; Radiopharmaceuticals; Sensitivity and Specificity; Technetium Tc 99m Sestamibi; Thyroid Neoplasms; Thyroid Nodule; Tomography, Emission-Computed

We prospectively studied 26 patients with cold thyroid nodules (five malignant and 21 benign nodules) on Tc-99m pertechnetate scintigraphy to investigate the diagnostic value of Tc-99m tetrofosmin scintigraphy and color-Doppler sonography in differentiating malignant from benign thyroid nodules. In each patient, Tc-99m Tetrofosmin uptake in the nodule and intranodule vascularity were assessed semiquantatively. Both the uptake and vascularity were classified as low, Iso or high. Eight out of 26 nodules showed high Tc-99m tetrofosmin uptake; five of them were malignant. Eight (including four malignant tumors) out of 26 nodules showed increased vascularity compared with normal thyroid tissue on color-Doppler sonography. In six out of eight patients with high uptake of Tc99m-tetrofosmin, increased vascularity was observed. The sensitivity, specificity, negative predictive value, and positive predictive value of Tc-99m tetrofosmin scintigraphy and color-Doppler sonography were determined to be 100% and 80%, 85% and 80%, 62% and 50%, and 100% and 94%, respectively. We conclude that color-Doppler sonography seems to have limited value in the detection of malignant thyroid nodules. However, Tc-99m tetrofosmin scintigraphy is a sensitive method to use in diagnosing malignant nodules, although it is not specific for the detection of malignant nodules.

Topics: Adenocarcinoma, Follicular; Adenoma; Adolescent; Adult; Carcinoma, Papillary; Diagnosis, Differential; Female; Humans; Male; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Predictive Value of Tests; Prospective Studies; Radionuclide Imaging; Radiopharmaceuticals; Sensitivity and Specificity; Thyroid Gland; Thyroid Neoplasms; Thyroid Nodule; Thyroiditis; Ultrasonography, Doppler, Color

Technetium-99m tetrofosmin, a lipophilic cationic complex molecule, was introduced for myocardial imaging. In some biodistribution studies it has also been reported to accumulate in the thyroid gland. Our objectives were to determine which thyroid nodules retain tetrofosmin and whether preoperative evaluation of malignancy is possible. Tetrofosmin scintigraphy was performed in 57 patients with a cold thyroid nodule on previously performed pertechnetate scintigraphy. All patients had undergone ultrasonography and sonographically guided fine-needle aspiration biopsy. The tetrofosmin scintigrams were obtained 5 min (early image) and 1 h (late image) after intravenous injection of 370 MBq. Only nodules that showed clear tracer retention after 1 h in comparison with retention at 5 min were classified as TETRO positive. Nodules without late retention were classified as TETRO negative. All patients underwent surgery and the histological results were compared with the results of tetrofosmin scintigraphy. Ten out of 11 patients with thyroid carcinoma (two pT1, three pT2, five pT4) were TETRO negative. One patient with papillary carcinoma (pT2) was TETRO positive. The mean nodular to thyroid tissue (N/T) ratio for the late scan was 1.0+/-0.20. There were 21 patients with thyroid adenomas (seven follicular, seven microfollicular and seven oxyphilic); 15 of these patients were TETRO positive and six TETRO negative. The mean N/T ratio for the late images was 1.34+/-0.41. All patients with degenerative goitre (24 cases) and the one patient with Hashimoto's disease were TETRO negative after 1 h and the N/T ratio was 0.92+/-0.12 on the late scan. Our results indicate that 99mTc-tetrofosmin scanning is of little value preoperatively in distinguishing thyroid carcinoma from other thyroid nodules. Tetrofosmin tends to demonstrate thyroid adenomas but does not have a routine role in the assessment of thyroid nodules.

Topics: Adenocarcinoma, Follicular; Adenoma; Carcinoma, Papillary; Diagnosis, Differential; Female; Humans; Male; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Sodium Pertechnetate Tc 99m; Thyroid Neoplasms; Thyroid Nodule

Technetium-99m tetrofosmin is a lipophilic phosphine used for myocardial perfusion imaging. Biodistribution studies have shown significant thyroid uptake of tetrofosmin and preliminary reports have suggested that tetrofosmin imaging may be of value in patients with thyroid cancer. In this study, tetrofosmin whole-body scintigraphy was performed in 35 patients with evidence of thyroid diseases. All patients underwent laboratory evaluation of thyroid function as well as 99mTc pertechnetate scan, thallium-201 (n=16) 99mTc-methoxyisobutylisonitrile (MIBI) (n=19) whole-body studies. Thyroid images were semi-quantitatively analysed by a 4-point score: 0=no significant uptake; 1=uptake increased as compared to background activity, but inferior to normal thyroid tissue; 2=uptake equal to normal thyroid tissue; 3=uptake superior to normal thyroid tissue. Pathology examinations were obtained. A total of 41 thyroid nodules were detected, of which 15 were goitre nodules, 13 adenomas and 13 malignant lesions. In goitre nodules, concordant results of tetrofosmin and pertechnetate uptake (score 1 or 0) were observed in the majority of lesions (87%). In function adenomas (n=10), both tetrofosmin uptake and pertechnetate uptake were score 3. In non-function adenomas (n=3), tetrofosmin uptake was score 3, while pertechnetate uptake was score 0. In six malignant lesions, tetrofosmin uptake was score 3, while pertechnetate uptake was score 0; in the other seven lesions, where a prevalence of goitre abnormalities was observed, results of tetrofosmin and pertechnetate uptake were similar (score 0 or 1). In seven (70%) of the ten patients with malignant nodules, whole-body tetrofosmin images showed increased abnormal uptake in a total of 28 extra-thyroid tumour sites, as subsequently confirmed by other techniques. When tetrofosmin images were compared to 201Tl and 99mTc-MIBI scans, concordant results were observed in all cases. In conclusion, tetrofosmin imaging may be particularly useful to characterize and stage patients with malignant thyroid nodules; it shows similar results to thallium but provides better image quality. Comparable findings were observed between tetrofosmin and MIBI studies. Thus, tetrofosmin may be an alternative to thallium and MIBI in the aforementioned patients.

Topics: Adenoma; Female; Goiter, Nodular; Humans; Male; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Sodium Pertechnetate Tc 99m; Technetium Tc 99m Sestamibi; Thallium Radioisotopes; Thyroid Neoplasms; Thyroid Nodule