18F-FDG PET/CT demonstration of a liver metastasis in a patient with papillary thyroid cancer.

A 51-year-old woman with papillary thyroid cancer had recurrent disease. An unexpected FDG-avid hepatic metastasis was identified. Follow-up contrast-enhanced CT scan showed a hepatic lesion, compatible with malignancy. Histopathologic examination demonstrated metastatic carcinoma, consistent with thyroid primary. Few studies reported liver metastases originating from thyroid cancer on FDG PET. These were medullary thyroid carcinomas (MTC) or poorly differentiated cancers. There are no reports describing liver metastasis from PTC diagnosed by FDG PET/CT.

Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists.

OBJECTIVE: Thyrotoxicosis has multiple etiologies, manifestations, and potential therapies. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions and patient preference. This article describes evidence-based clinical guidelines for the management of thyrotoxicosis that would be useful to generalist and subspeciality physicians and others providing care for patients with this condition. METHODS: The development of these guidelines was commissioned by the American Thyroid Association in association with the American Association of Clinical Endocrinologists. The American Thyroid Association and American Association of Clinical Endocrinologists assembled a task force of expert clinicians who authored this report. The task force examined relevant literature using a systematic PubMed search supplemented with additional published materials. An evidence-based medicine approach that incorporated the knowledge and experience of the panel was used to develop the text and a series of specific recommendations. The strength of the recommendations and the quality of evidence supporting each was rated according to the approach recommended by the Grading of Recommendations, Assessment, Development, and Evaluation Group. RESULTS: Clinical topics addressed include the initial evaluation and management of thyrotoxicosis; management of Graves' hyperthyroidism using radioactive iodine, antithyroid drugs, or surgery; management of toxic multinodular goiter or toxic adenoma using radioactive iodine or surgery; Graves' disease in children, adolescents, or pregnant patients; subclinical hyperthyroidism; hyperthyroidism in patients with Graves' ophthalmopathy; and management of other miscellaneous causes of thyrotoxicosis. CONCLUSIONS: One hundred evidence-based recommendations were developed to aid in the care of patients with thyrotoxicosis and to share what the task force believes is current, rational, and optimal medical practice.

Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists.

BACKGROUND: Thyrotoxicosis has multiple etiologies, manifestations, and potential therapies. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions and patient preference. This article describes evidence-based clinical guidelines for the management of thyrotoxicosis that would be useful to generalist and subspeciality physicians and others providing care for patients with this condition. METHODS: The development of these guidelines was commissioned by the American Thyroid Association in association with the American Association of Clinical Endocrinologists. The American Thyroid Association and American Association of Clinical Endocrinologists assembled a task force of expert clinicians who authored this report. The task force examined relevant literature using a systematic PubMed search supplemented with additional published materials. An evidence-based medicine approach that incorporated the knowledge and experience of the panel was used to develop the text and a series of specific recommendations. The strength of the recommendations and the quality of evidence supporting each was rated according to the approach recommended by the Grading of Recommendations, Assessment, Development, and Evaluation Group. RESULTS: Clinical topics addressed include the initial evaluation and management of thyrotoxicosis; management of Graves' hyperthyroidism using radioactive iodine, antithyroid drugs, or surgery; management of toxic multinodular goiter or toxic adenoma using radioactive iodine or surgery; Graves' disease in children, adolescents, or pregnant patients; subclinical hyperthyroidism; hyperthyroidism in patients with Graves' ophthalmopathy; and management of other miscellaneous causes of thyrotoxicosis. CONCLUSIONS: One hundred evidence-based recommendations were developed to aid in the care of patients with thyrotoxicosis and to share what the task force believes is current, rational, and optimal medical practice.

Thyroid stunning: fact or fiction?

Stunning of thyroid tissue by diagnostic activities of (131)I has been described by some investigators and refuted by others. The support both for and against stunning has at times been enthusiastic and vigorous. We present the data from both sides of the debate in an attempt to highlight the strengths and deficiencies in the investigations cited. Clinical, animal, and in vitro studies are included. There are considerable differences in clinical practice, such as the administered activity for diagnostic whole-body scan, delay between diagnostic scan and treatment, time between treatment and posttherapy scanning, and timing of follow-up studies, that have to be analyzed with care. Other factors that often cannot be judged, such as levels of thyroid-stimulating hormone and serum iodine at time of diagnostic testing versus treatment could have an influence on stunning. Larger diagnostic doses and longer delays to therapy appear to increase the likelihood of stunning. The stunning effect of early-absorbed radiation from the therapy should also be considered.

Efficacy of 18F-FDG PET/CT in the evaluation of patients with recurrent cervical carcinoma.

PURPOSE: Only a limited number of studies have evaluated the efficacy of 18F-FDG PET/CT for recurrent cervical carcinoma, which this study seeks to expand upon. METHODS: This is a retrospective study of 30 women with cervical carcinoma who had a surveillance PET/CT after initial therapy. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were calculated using a 2 × 2 contingency table with pathology results (76%) or clinical follow-up (24%) as the gold standard. The Wilson score method was used to perform 95% confidence interval estimations. RESULTS: The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of PET/CT for the detection of local recurrence at the primary site were 93, 93, 93, 86, and 96%, respectively. The same values for the detection of distant metastases were 96, 95, 95, 96, and 95%, respectively. Seventy-one percent of the scans performed in symptomatic patients showed true-positive findings. In comparison, 44% of scans performed in asymptomatic patients showed true-positive findings. But, all patients subsequently had a change in their management based on the PET/CT findings such that the effect was notable. The maximum standardized uptake value ranged from 5 to 28 (average: 13 ± 7) in the primary site and 3 to 23 (average: 8 ± 4) in metastases which were significantly different (p = 0.04). CONCLUSION: This study demonstrates favorable efficacy of 18F-FDG PET/CT for identification of residual/recurrent cervical cancer, as well as for localization of distant metastases.

Uncommon causes of thyrotoxicosis.

Apart from the common causes of thyrotoxicosis, such as Graves' disease and functioning nodular goiters, there are more than 20 less common causes of elevated free thyroid hormones that produce the symptoms and signs of thyrotoxicosis. This review describes these rarer conditions and includes 14 illustrative patients. Thyrotropin and free thyroxine should be measured and, when the latter is normal, the free triiodothyronine level should be obtained. Measurement of the uptake of (123)I is recommended for most patients.

Treatment of micropapillary carcinoma of the thyroid: where do we draw the line?

Two patients with papillary thyroid cancer were seen in consultation after they had been treated in other medical centers. Their cancers measured 1 and 1.2 mm, respectively. Both patients were treated by two thyroid operations and (131)I ablation. We believe that, apart from lobectomy, these therapies were not justified. We draw attention to this to provide a topic for debate and to attempt to prevent this happening to other patients.

Incidental gallbladder visualization on nonhepatobiliary nuclear medicine studies: case series and review of the literature.

Gallbladder uptake is occasionally encountered with commonly used nonhepatobiliary radiopharmaceuticals. Identification of the biliary tract by a nonhepatobiliary agent can identify disease, such as uptake of labeled white blood cells. However, in most cases, gallbladder uptake of nonhepatobiliary tracers is not due to pathology in these cases. It is important to avoid attributing gallbladder uptake to disease in the gallbladder or adjacent anatomic structures. We present 3 cases of unexpected gallbladder tracer uptake and provide a review of the literature describing incidental gallbladder uptake on nonhepatobiliary nuclear medicine studies. The potential for misdiagnosis and the steps taken to avoid this are discussed.

Recurrent silent thyroiditis: a report of four patients and review of the literature.

Silent thyroiditis, excluding postpartum thyroiditis and destructive amiodarone thyroiditis, is a relatively uncommon cause of thyrotoxicosis and recurrent cases are even rarer. We present four patients with recurrent silent thyroiditis. The number of episodes ranged from two to nine. All four patients had episodes that were similar in duration (4-6 weeks) as well as in their clinical (no viral prodrome or neck pain), biochemical (high total triiodothyronine [T(3)], free thyroxine [T(4)], and low thyrotropin [TSH] presence of antibodies to thyroid antigens), and scintigraphic (low radioiodine uptake) findings. Individual symptoms and symptom-free duration (from 1 to 4 years) were more variable. No associations were found with regard to medications, pregnancies, or other disease states previously implicated in thyroiditis. One patient was unsuccessfully prescribed thyroid hormone to prevent recurrence. Three were treated with radioablative iodine therapy during the recovery phase of an episode; they became hypothyroid and take replacement l-thyroxine. They have remained symptom free.

F-18 FDG PET/CT in the management of thyroid cancer.

PURPOSE: There are approximately 32,000 new cases of thyroid carcinoma annually in the United States. F-18 FDG PET/CT has an established role in cancer management, including thyroid cancer, usually in patients who are thyroglobulin (Tg) positive/iodine negative. We reviewed our experience with F-18 FDG PET/CT in thyroid cancer, with an emphasis on correlation with Tg, and maximum standardized uptake values (SUV). We also analyzed the role of thyroid stimulating hormone (TSH) on PET/CT results. MATERIALS AND METHODS: This is a retrospective study (January 2003 to December 2006) of 76 patients with differentiated thyroid cancer, who had F-18 FDG PET/CT scans. There were 44 women and 32 men, with age range of 20 to 81 years (average, 51.1 +/- 18.1). The administered doses of F-18 FDG ranged from 396 to 717 MBq (15.8-19.4 mCi) (average, 566 +/- 74.8) (15.3 +/- 2). Reinterpretation of the imaging studies for accuracy and data analysis from medical records were performed. RESULTS: A total of 98 PET/CT scans were analyzed (59 patients had 1 scan, 12 patients had 2, and 5 patients had 3). PET/CT was 88.6% sensitive (95% CI: 78.-94.3) and 89.3% specific (95% CI: 71.9-97.1). Mean Tg level was 1203 ng/mL (range, 0.5-28,357) in patients with positive PET/CT and 9.72 ng/mL (range, 0.5-123.0) in patients with negative PET/CT scans (P = 0.0389). Mean SUV max was 10.8 (range, 2.5-32) in the thyroid bed recurrence/residual disease and 7.53 (range, 2.5-26.2) in metastatic lesions (P = 0.0114). Mean SUV max in recurrent/residual disease in patients with TSH 30 mIU/L was 8.1 (range, 2.6-32) (P = 0.2994). CONCLUSION: F-18 FDG PET/CT had excellent sensitivity (88.6%) and specificity (89.3%) in this patient population. Metastatic lesions were reliably identified, but were less F-18 FDG avid than recurrence/residual disease in the thyroid bed. TSH levels at the time of PET/CT did not appear to impact the FDG uptake in the lesions or the ability to detect disease. In the setting of high or rising levels of Tg, our study confirms that it is indicated to include PET/CT in the management of patients with differentiated thyroid cancer.

Treatment of thyrotoxicosis.

In this review, the causes of thyrotoxicosis and the treatment of syndromes with increased trapping of iodine are discussed. The benefits and the potential side effects of 3 frequently used therapies--antithyroid medications, thyroidectomy, and (131)I treatment--are presented. The different approaches to application of (131)I treatment are described. Treatment with (131)I has been found to be cost-effective, safe, and reliable.

Clinical role of 18F-FDG PET/CT in the management of squamous cell carcinoma of the head and neck and thyroid carcinoma.

18F-FDG PET/CT has rapidly become a widely used imaging modality for evaluating a variety of malignancies, including squamous cell carcinoma of the head and neck and thyroid cancer. Using both published data and the multidisciplinary experience at our institution, we provide a practical set of guidelines and algorithms for the use of 18F-FDG PET/CT in the evaluation and management of head and neck cancer and thyroid cancer.

Reproducibility of whole-body 131I scan and serum thyrotropin and stimulated thyroglobulin values in patients studied twice after injection of recombinant human thyrotropin.

PURPOSE: Recombinant human TSH (rhTSH) is used to increase radioiodine uptake during imaging of thyroid cancer, obviating the need to render the patient hypothyroid. We assessed the reproducibility of radioiodine uptake, serum thyrotropin (TSH), and stimulated serum thyroglobulin (Tg) levels after rhTSH administration. METHODS: A retrospective review was performed of patients at Stanford who underwent whole-body (131)I scanning for surveillance of thyroid cancer twice after thyroidectomy and (131)I ablation, with rhTSH prior to each scan. Forty-eight hour radioiodine uptake, peak serum TSH, and stimulated serum Tg levels for each study were recorded. Paired t tests and correlation analysis were used to assess interexamination repeatability. RESULTS: Twenty-three patients underwent two scintiscans with rhTSH, for a total of 46 exams. There was no significant difference between percent uptake at 48 h in the paired exams (p=0.40). Serum TSH level was measured in 45 of 46 exams; TSH exceeded 50 mIU/l in all cases, and there was no significant difference between paired TSH levels (p=0.93). All patients had stimulated serum Tg levels measured, with no significant difference between paired Tg levels (p=0.40); after excluding one patient whose Tg changed from 15.8 ng/ml to undetectable between scans without interval treatment, the p value rose to 0.95. There was a strong correlation among paired uptake values (r=0.85, p<0.0001), peak serum TSH (r=0.69, p=0.0003), and stimulated Tg levels (r=0.81, p<0.0001). No discordant scan interpretations were reported. CONCLUSION: Forty-eight hour radioiodine uptake, peak serum TSH, and stimulated serum Tg levels after administration of rhTSH are repeatable between studies, demonstrating reproducibility of diagnostic results without rendering patients hypothyroid.

F-18 FDG PET/CT demonstration of an adrenal metastasis in a patient with anaplastic thyroid cancer.

An adrenal metastasis was identified on an F-18 FDG PET/CT scan in a patient with anaplastic thyroid cancer. There are very few reports of thyroid cancer, even anaplastic thyroid cancer, metastasizing to the adrenal.