Thyroid nodule other imaging findings: Difference between revisions
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** Most malignant thyroid nodules | ** Most malignant thyroid nodules | ||
Posttherapy whole-body iodine scanning is typically conducted approximately 1 week after RAI therapy to visualize metastases. | Posttherapy whole-body iodine scanning is typically conducted approximately 1 week after RAI therapy to visualize metastases. | ||
==== Diagnostic whole-body RAI scans ==== | |||
DxWBS, either following thyroid hormone withdrawal or rhTSH, 6–12 months after remnant ablation may be of value in the follow-up of patients with high or intermediate risk of persistent disease, but should be done with 123I or low activity 131I | |||
Torlontano M, Crocetti U, D’Aloiso L, Bonfitto N, Di Giorgio A, Modoni S, Valle G, Frusciante V, Bisceglia M, Filetti S, Schlumberger M, Trischitta V 2003 Serum thyroglobulin and 131I whole body scan after recombinant human TSH stimulation in the follow-up of low-risk patients with differentiated thyroid cancer. Eur J Endocrinol 148:19–24 | |||
=== FDG-PET scan === | === FDG-PET scan === | ||
| Line 32: | Line 37: | ||
There is insuffiecient evidence to recommend to or against routine clinical use | There is insuffiecient evidence to recommend to or against routine clinical use | ||
Usage indications: | |||
* simple disease localization in Tg-positive, RAI scan–negative patients | |||
* Initial staging and follow-up of high-risk patients with poorly differentiated thyroid cancers unlikely to concentrate RAI in order to identify sites of disease that may be missed with RAI scanning and conventional imaging. | |||
* Initial staging and follow-up of invasive or metastatic Hurthle cell carcinoma. | |||
* As a powerful prognostic tool for identifying which patients with known distant metastases are at highest risk for disease-specific mortality. | |||
* As a selection tool to identify those patients unlikely to respond to additional RAI therapy. | |||
* As a measurement of post treatment response following external beam irradiation, surgical resection, embolization, or systemic therapy. | |||
Larson SM, Robbins R 2002 Positron emission tomography in thyroid cancer management. Semin Roentgenol 37:169–174. 316. | |||
Leboulleux S, Schroeder PR, Busaidy NL, Auperin A, Corone C, Jacene HA, Ewertz ME, Bournaud C, Wahl RL,Sherman SI, Ladenson PW, Schlumberger M 2009 Assessment of the incremental value of recombinant TSH stimulation before FDG PET=CT imaging to localize residual differentiated thyroid cancer. J Clin Endocrinol Metab 94:1310–1316. | |||
False-positive 18FDG-PET findings can be due to: | |||
* Inflammatory lymph nodes | |||
* Suture granulomas | |||
* Increased muscle activity | |||
Therefore, cytologic or histologic confirmation is required before one can be certain that an 18FDG-positive lesion represents metastatic disease. | |||
==== Iodine 131 single photon emission computed tomography (SPECT)=CT fusion imaging ==== | ==== Iodine 131 single photon emission computed tomography (SPECT)=CT fusion imaging ==== | ||
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Thyroid nodule other imaging findings On the Web |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Other Imaging Studies
Radionuclide thyroid scan/scintigraphy
using either technetium 99 mTc pertechnetate or 123I
radionuclide scan is contraindicated during pregnancy
Thyroid scintigraphy is useful to determine the functional status of a nodule. It is specifically indicated in patients with thyroid nodule and a low serum TSH to determine if the nodule is autonomously functioning.
In scintigraphy, iodine radioisotopes (more commonly used; usually 123I) or technetium pertechnetate (99Tc), are injected to the patient and then the radioisotope uptake time by the thyroid gland is measured.4406304 16910877
- High radioisotopes uptake=Hot nodule:
- Hyperfunctioning nodules
- Low radioisotopes uptake=Cold nodule:
- Most benign nodules
- Most malignant thyroid nodules
Posttherapy whole-body iodine scanning is typically conducted approximately 1 week after RAI therapy to visualize metastases.
Diagnostic whole-body RAI scans
DxWBS, either following thyroid hormone withdrawal or rhTSH, 6–12 months after remnant ablation may be of value in the follow-up of patients with high or intermediate risk of persistent disease, but should be done with 123I or low activity 131I
Torlontano M, Crocetti U, D’Aloiso L, Bonfitto N, Di Giorgio A, Modoni S, Valle G, Frusciante V, Bisceglia M, Filetti S, Schlumberger M, Trischitta V 2003 Serum thyroglobulin and 131I whole body scan after recombinant human TSH stimulation in the follow-up of low-risk patients with differentiated thyroid cancer. Eur J Endocrinol 148:19–24
FDG-PET scan
improve diagnostic accuracy of indeterminate thyroid nodules
In patients with thyroid PET incidentaloma, the incidence of primary thyroid malignancy is very high
24902804
There is insuffiecient evidence to recommend to or against routine clinical use
Usage indications:
- simple disease localization in Tg-positive, RAI scan–negative patients
- Initial staging and follow-up of high-risk patients with poorly differentiated thyroid cancers unlikely to concentrate RAI in order to identify sites of disease that may be missed with RAI scanning and conventional imaging.
- Initial staging and follow-up of invasive or metastatic Hurthle cell carcinoma.
- As a powerful prognostic tool for identifying which patients with known distant metastases are at highest risk for disease-specific mortality.
- As a selection tool to identify those patients unlikely to respond to additional RAI therapy.
- As a measurement of post treatment response following external beam irradiation, surgical resection, embolization, or systemic therapy.
Larson SM, Robbins R 2002 Positron emission tomography in thyroid cancer management. Semin Roentgenol 37:169–174. 316.
Leboulleux S, Schroeder PR, Busaidy NL, Auperin A, Corone C, Jacene HA, Ewertz ME, Bournaud C, Wahl RL,Sherman SI, Ladenson PW, Schlumberger M 2009 Assessment of the incremental value of recombinant TSH stimulation before FDG PET=CT imaging to localize residual differentiated thyroid cancer. J Clin Endocrinol Metab 94:1310–1316.
False-positive 18FDG-PET findings can be due to:
- Inflammatory lymph nodes
- Suture granulomas
- Increased muscle activity
Therefore, cytologic or histologic confirmation is required before one can be certain that an 18FDG-positive lesion represents metastatic disease.
Iodine 131 single photon emission computed tomography (SPECT)=CT fusion imaging
may provide superior lesion localization after remnant ablation, but it is still a relatively new imaging modality