99mTc-MIBI SPECT/CT imaging contribution in the diagnosis of patients with hyperparathyroidism

  Hyperparathyroidism is presented with increased parathyroid hormone (PTH) secretion due to hyperfunctioning of one or more of the four parathyroid glands. Primary hyperparathyroidism (p-HPT) can be due to parathyroid adenoma, hyperplasia or carcinoma of the parathyroid gland. Secondary hyperparathyroidism (s-HPT) is usually a response to hypocalcaemia and consecutive hyperplasia of the glands. Our aim was to compare the efficacy of 99mTc-methoxyisobutylisonitrile (MIBI) SPECT/CT in identification of the location of the lesion(s) in cases of HPT by comparing these results with the findings of ultrasound (US) and planar scintigraphy. Forty one consecutive patients (54±17 age, 12 males and 29 females) with primary or secondary hyperparathyroidism were included. All patients were examined by US and afterwards patients underwent conventional double-phase 99mTc-MIBI scintigraphy combined with neck SPECT/CT procedure. Planar images (early and delayed), US and SPECT/CT image sets were evaluated for adenoma localization at the neck and thorax. Regions of interest (ROIs), equal sized, were selected and compared, over the hyperfunctioning parathyroid tissue (accumulated impulses-counts value) and over the contralateral lobe of the thyroid gland (control counts value). The ultrasonography detected 24 positive findings. The late phase of planar scan detected 26 positive findings. SPECT/CT presented with bigger detection rate than late planar phase or US (75.6%, 63.4%, 61.5%) and with higher sensitivity (100%, 83.8%, 77.4%), respectively. The SPECT/CT study seems reliable, sensitive and with added value in diagnosing hyperparathyroidism as a complementary method to planar scintigraphy. US as compatible method, should be performed prior the scintigraphy protocols.