Value of three-dimensional arterial spin labeling in distinguishing between benign and malignant thyroid nodules
Objective:To assess the diagnostic efficacy of three-dimensional pseudo-continuous arterial spin labeling(3D-pCASL)for thyroid nodules.Materials and Methods:A total of 207 patients who underwent thyroid magnetic resonance imaging(MRI)at the Chinese Academy of Medical Sciences/Cancer Hospital&Shenzhen Hospital from November 2021 to April 2023 were included in this study,among which 74 patients had normal unilateral thyroid glands.The 3D-pCASL sequence was acquired along the horizontal axis with a post-labeling delay(PLD)time set at 1525 ms,and the labeling plane was positioned at the origin of the left common carotid artery.Blood flow(BF)measurements of both normal thyroid glands and thyroid nodules were obtained using AW 4.7 workstation.The t-test or non-parametric test was employed for between-group comparisons.Receiver operating characteristic(ROC)curve analysis and calculation of area under the curve(AUC)were performed to evaluate the diagnostic efficacy of BF in distinguishing benign from malignant thyroid nodules,as well as to compare papillary thyroid carcinoma(PTC)with non-papillary thyroid carcinoma(non-PTC).Results:There was no significant difference in BF between male and female(P>0.05).The average BF of the normal lateral lobe of the thyroid was(162.73±24.24)mL/(100 g·min).A total of 235 thyroid nodules were observed in 207 patients(44 benign and 191 malignant).BF of malignant nodules was significantly higher than that of benign nodules,and the difference was statistically significant(left lobe t=6.607 and right lobe t =5.590,both P<0.001).The cut-off value of BF for differentiating benign from malignant thyroid nodules was 177.96 mL/(100 g·min),the sensitivity,specificity and accuracy were 73.1%,93.7%and 89.4%,respectively(AUC=0.861).There was no significant difference in BF between PTC and non-PTC(t=1.578,P=0.124).Conclusions:3D-pCASL technology has great value in the differential diagnosis of benign and malignant thyroid nodules,and its quantitative value BF has limited value in differentiating different pathological types of thyroid cancer.