CASE 60 A 33–year-old woman presents with palpitations and heat intolerance. Laboratory values confirm thyrotoxicosis with suppressed thyroid-simulating hormone (TSH) and elevated thyroxine (T4) levels. She is 3 months postpartum. Fig. 60.1 Anterior parallel-hole collimator view, 99mTc. Fig. 60.2 Anterior parallel-hole collimator view with “hot” suprasternal notch marker, 99mTc. • 12 mCi of 99mTc-pertechnetate administered intravenously at 10 minutes before scan • Five-minute anterior parallel-hole collimator images without (Fig. 60.1) and with (Fig. 60.2) “hot” sternal notch marker Absence of 99mTc localization and nonvisualization of the thyroid gland. Note prominent, symmetric salivary glands. See Table 60.1 for a comparative analysis of poorly visualized or nonvisualized thyroid glands.
Clinical Presentation
Technique
Image Interpretation
Differential Diagnosis
Hypothyroid | Euthyroid | Hyperthyroid |
After 131I ablation, surgery, radiation therapy | Diet rich in iodine | Subacute (granulomatous), silent (lymphocytic), postpartum thyroiditis |
End-stage goiter | Recent iodinated contrast media | Factitious thyrotoxicosis |
Hashimoto thyroiditis |
