The Value of Imaging of the Parathyroid Glands in Secondary Hyperparathyroidism

Abstract

Este estimat că un procent important, de până la 90%, din pacienţii cu insuficienţa renală cronică dezvoltă hiperparatiroidism secundar (HPS). Cu toate că boala prezintă multiple manifestări, cea mai importantă caracteristică patologică, din punctul de vedere al mortalităţii crescute, e reprezentată de calcificările ectopice arteriale, miocardice şi valvulare cardiace. Acestea sunt progresive şi conduc la hipertensiune arterială, hipertrofie ventriculară stângă, blocuri atrio-ventriculare, angină pectorală şi infarct miocardic. Aşadar riscul evenimentelor cardio-vasculare este mult crescut. Eşecul terapiei medicamentoase în a stăpâni progresia bolii reprezintă o indicaţie pentru paratiroidectomie. In HPS sunt afectate toate glandele paratiroide, de aici necesitatea de a decela intraoperator 4 glande, prin explorare cervicală bilaterală. Totuşi, având în vedere posibilitatea unor localizări ectopice a acestor glande cât şi eventualitatea unora supranumerare, este de dorit a avea preoperator o hartă imagistică cât mai exactă, evitând astfel riscul recurenţei postoperatorii. Investigaţiile imagistice disponibile sunt reprezentate de ecografia regiunii cervicale, scintigrafia paratiroidiană şi de cele de linia a doua-examinare CT sau RMN. Dacă în hiperparatiroidismul primar, unde există un singur adenom paratiroidian (sau două), rezultatele imagistice preoperatorii sunt satisfăcătoare, în HPS există destule cazuri în care imagistica nu evidenţiază toate cele patru glande paratiroide. Cuvinte cheie: paratiroide, hiperparatiroidism secundar, insuficienţa renală cronică, scintigrafie

Diagnosis performance of ultrasonography, dual-phase 99mTc-MIBI scintigraphy, early SPECT/CT and delayed SPECT/CT in preoperative localization of parathyroid gland in secondary hyperparathyroidism

“…In our study, we directly compared US, dual-phase 99m Tc-MIBI scintigraphy, early SPECT/CT and delayed SPECT/CT in the SHPT patients. The overall sensitivity and accuracy of early phase SPECT/CT was higher than the other techniques and also slightly higher than the previous studies [25,30]. For detecting ectopic parathyroid glands, the sensitivity of early SPECT/CT was significantly higher than US and 99m Tc-MIBI scintigraphy which is similar to the previous study(90.5%) [24].…”

“…Therefore, preoperative imaging and localization are critical to a successful operation. US is the most used imaging investigation for the advantage of low cost and simple manipulation, but limited in the discovery of ectopic parathyroid glands and in the dependence on the examiner's experience [30]. CT is useful in cases where US does not detect the lesions, and the sensitivity is increased in detecting the ectopic glands of mediastinum but is lower for the glands located in the thyroid lodge [31].…”

“…CT is useful in cases where US does not detect the lesions, and the sensitivity is increased in detecting the ectopic glands of mediastinum but is lower for the glands located in the thyroid lodge [31]. MRI has the advantage of no radiation and has a discreetly increased sensitivity than CT, and it is especially useful in detecting mediastinal parathyroid glands [30].Different from the above anatomical imaging, 99m Tc-MIBI imaging is a functional exploration with the advantage of detecting ectopic glands and it is based on the different washout rate between the thyroid tissue and parathyroid hyperplasia [32]. 99m Tc-MIBI scintigraphy has high sensitivity and specificity, but also has multiple limitation, such as lacks precise anatomical location of the lesion [33], making the differential diagnosis of parathyroid hyperplasia from thyroid lesions difficult.…”

Diagnostic performance of ultrasonography, dual-phase 99mTc-MIBI scintigraphy, early and delayed 99mTc-MIBI SPECT/CT in preoperative parathyroid gland localization in secondary hyperparathyroidism

“…In our study, we directly compared US, dual-phase 99m Tc-MIBI scintigraphy, early and delayed 99m Tc-MIBI SPECT/CT in SHPT patients. The overall sensitivity and accuracy of early SPECT/CT were higher than those of the other techniques and slightly higher than those in previous studies [23,24]. For detecting ectopic parathyroid glands, the sensitivity of early 99m Tc-MIBI SPECT/CT was signi cantly higher than that of US and dual-phase 99m Tc-MIBI scintigraphy, and the percentage was similar to that reported in a previous study (90.5%) [6].…”

“…Second, some hyperplastic parathyroid glands were positive for p-glycoprotein, and 99m Tc-MIBI was quickly eliminated from the parathyroid glands, leading to negative uptake images on scintigraphy [39]. Third, the ndings on dual-phase 99m Tc-MIBI scintigraphy are related to the size and weight of the parathyroid glands, and smaller parathyroid gland lesions can be easily missed [24,40]. Fourth, lesions located behind the thyroid gland and with similar 99m Tc-MIBI uptake are di cult to detect on scintigraphy but can be identi ed on SPECT/CT.…”