The role of technetium-99m methoxyisobutylisonitrile scintigraphy in the planning of therapy and follow-up of patients with differentiated thyroid carcinoma after surgery

D Rubello, R Mazzarotto, D Casara
European Journal of Nuclear Medicine 2000, 27 (4): 431-40
The aim of this study was to investigate the possible role of technetium-99m methoxyisobutylisonitrile (MIBI) scan in planning post-surgical therapy and follow-up in patients with differentiated thyroid carcinoma (DTC). Four groups of DTC patients were considered: Group 1 comprised 122 patients with high serum thyroglobulin (s-Tg) levels and negative high-dose iodine-131 scan during follow-up who had previously undergone total thyroidectomy and 131I treatment. Group 2 consisted of 27 patients who had previously undergone total thyroidectomy and 131I treatment but were now considered disease-free; this group was considered as controls. Group 3 comprised 49 patients studied after total thyroidectomy but prior to 131I scan. Finally, group 4 consisted of 21 patients who had previously undergone partial thyroidectomy alone. MIBI scan, neck ultrasonography (US), and s-Tg measurements during suppressive hormonal therapy (SHT) were obtained in all patients. Neck and chest computed tomography (CT) or magnetic resonance imaging (MRI) was also performed in group 1 patients. In group 1, MIBI scan and US were very sensitive in detecting cervical lymph node metastases (93.54% and 89.24%, respectively). Furthermore, MIBI scan and US played a complementary role in several patients, yielding a global sensitivity of 97.84%. In contrast, CT/MRI sensitivity for cervical lymph node metastases was very low (43.01%). MIBI scan also showed a higher sensitivity than CT/MRI in detecting mediastinal lymph node metastases (100% vs 57.89%). Regarding distant metastases, MIBI scan provided results similar to those of conventional imaging (CT, MRI, 99mTc-methylene diphosphonate bone scan). In group 2, no false-positive cases were observed with MIBI scan (100% specificity). In group 3, MIBI scan correctly identified all the 131I-positive metastatic foci, except in two patients with micronodular pulmonary metastases that were visualised with 131I scan. In contrast, both MIBI scan and US showed low sensitivity (46.15% and 61.53%, respectively) compared with 131I scan in detecting thyroid remnants. s-Tg was increased in all patients with distant metastases but only in 56% of those with lymph node metastases. Furthermore, s-Tg was increased in 21.42% of patients with thyroid remnants alone (false-positive results). In group 4, MIBI scan was the only examination capable of detecting at an early stage a mediastinal lymph node metastasis in one patient. We conclude that the integrated MIBI scan/neck US protocol: (a) can be proposed as a first-line diagnostic procedure in the follow-up of DTC patients with high s-Tg levels and negative high-dose 131I scan, and (b) may be helpful in the follow-up of DTC patients who undergo partial thyroidectomy alone. Moreover, the combined MIBI scan/neck US/s-Tg protocol appears to be highly sensitive in identifying patients with metastatic disease after total thyroidectomy and prior to 1311 scan; consequently, it may play a prognostic role in distinguishing high-risk from low-risk DTC patients. However, due to the low sensitivity of MIBI scan and neck US in detecting thyroid remnants, this diagnostic approach cannot be used as a predictor of 131I scan results. Lastly, because of the high sensitivity of MIBI scan and neck US in revealing both functioning and non-functioning metastases, this integrated protocol might be helpful in the follow-up of high-risk DTC patients, particularly for the early detection of lymph node metastases in patients with undetectable s-Tg during SHT.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"