Clinical value of semiquantitative analysis of 99mTc-MIBI SPECT imaging for diagnosis of primal hyperparathyroidism

Objectives Many studies had shown that 99mTc-MIBI SPECT imaging was useful for the diagnosis and prognosis of primal hyperparathyroidism (PHPT). Because the limitation of sensitivity and specifity, there were just a few studies about semiquantitative analysis of 99mTc-MIBI imaging for diagnosis of PHPT. The purpose of this study was to investigate the value of semiquantitative analysis of 99mTc-MIBI imaging for diagnosis of PHPT.

Methods A total of 46 patients with PHPT (26 males, 20 females, average age 54.36±15.50y,), who had 99mTc-MIBI SPECT imaging before treatment, were studied retrospectively. Adenoma was diagnosed in 42 patients, hyperplasia in 2 and carcinoma in 2. Data collected included laboratory data (serum level of total calcium, phosphorous, parathyroid hormone (PTH) and alkaline phosphatase (ALP)), the tumor size in ultrasound, the size of ROI and alteration ratio of radioactivity in 99mTc-MIBI SPECT imaging. The correlation between the size of ROI and the tumor size in ultrasound, the alteration ratio and laboratory data was tested by Pearson correlation. The ROC curves of the alteration ratio were established.

Results The positive rate of 99mTc-MIBI imaging, ultrasound, serum level of total calcium, phosphorous, PTH and ALP was 92.8%, 71.4%, 95.2%, 69.9%, 95.2 and 57.1% respectively. There were positive correlation between the size of ROI and the tumor size in ultrasound, the alteration ratio and serum level of total calcium, the alteration ratio and serum level of PTH(r=0.298, 0.688, 0.532, all P<0.05). The cut-off values of the alteration ratio were 0.879 by ROC curves.

Conclusions 99mTc-MIBI SPECT imaging is valuable for the diagnosis of PHPT. The cut-off value of the alteration ratio of ROI is helpful for the early diagnosis and prediction of PHPT.