Considered rare disease in the past, primary hyperparathyroidism (PHPT) has dramatically increased in incidence over the past thirty years with the introduction of routine calcium measurements; it is now approximately 42 per 100 000 persons. By far, the most common lesion found in patients with PHPT is the solitary parathyroid adenoma, occurring in 85%-90% of patients, while in the rest 10%- 15% primary hyperplasia of the parathyroid glands is present. Currently, the most widely used surgical approach is minimally invasive parathyroidectomy which is associated with less post-surgery complications and shorter operation time. To be successful this procedure needs to rely on a precise preoperative localization of the abnormal parathyroid glands, hence preoperative parathyroid imaging gained so large importance. The rationale for locating abnormal parathyroid tissue prior to surgery is that the glands can be notoriously unpredictable in their location. There is a general consensus that the best imaging procedure identifying abnormal parathyroid glands is the preoperative scintigraphy with 99mTc-sestamibi or 99mTc-tetrofosmin. It is characterized with high sensitivity and specificity exceeding those of ultrasound, CT or MRI. Combining scintigraphy with the other imaging techniques increases the precision for topic localization.

Graves’ disease is an autoimmune organ specific disease characterized by excessive production of hormones from the thyroid gland and by its diffuse enlargement. The growth and function of the thyroid gland are stimulated by autoantibodies directed against the thyroid-stimulating hormone receptor. Pregnancies complicated by Graves’ disease are characterized with higher incidence of abortion, preterm delivery, low-birth- weight infants and neonatal mortality, as well as maternal complications such as heart failure, eclampsia and rarely thyroid storm. When fully controlled hyperthyroidism have excellent outcomes. Different therapeutic approaches are used in women with Graves’ planning pregnancy and in those when the disease is diagnosed after they became pregnant. Thionamides are the first choice for treatment, with Propylthyouracil being preferred for the first trimester and Methimazole for the second and third trimester. Aplasia cutis and some other malformations were associated with methimazole use during pregnancy. Monitoring the effect of treatment should ensure keeping maternal FT4 in the high normal range. Block-and replace regimen is not recommended and rdioiodine therapy is absolutely contraindicated. Thyroidectomy may be considered before pregnancy or in rare cases in the second trimester. Iodine is avoided because of the risk of fetal hypothyroidism and goiter. The use of beta-blockers is controversial. Noenatal thyrotoxicosis may occur in association with maternal Graves’ disease due to maternal TSAbs cross through the placenta.

The visualization of abnormal parathyroid glands is difficult due to their variations in number and localization. Noninvasive parathyroid imaging studies include 99m Tcsestamibi scintigraphy, ultrasonography, computed tomography scanning, magnetic resonance imaging, and positron emission tomography. There is a general consensus that the most sensitive and specific imaging modality, especially when it is combined with single-photon emission CT is the scintigraphy with 99m Tc-sestamibi or 99m Tctetrofosmin. 99m Tc-sestamibi scintigraphy significantly increases the role of preoperative scintigraphy in patients with hyperparathyroidism and allows unilateral surgical approach with minimally invasive parathyroidectomy to be used. Generally, three protocols with the use of two radiopharmaceuticals, 99m Tc-sestamibi or 99m Tc-tetrofosmin, are most widely applied: single-phase dual-isotope subtraction, dual-phase single-isotope and combination of both. Each one of them has specific advantages and disadvantages. While single parathyroid adenomas are localized with greater precision, hyperfunctioning parathyroid hyperplastic cells represent a real challenge to the imaging modalities. Several factors can influence the radionuclide uptake in pathologically changed parathyroid cells, like the size, the level of their functional activity, the quantity of oxyphilic cells, mitochondria, P glycoprotein and other MDR gene products.