Objective To compare the value of two-dimensional high-frequency ultrasound, acoustic pulsed radiant force imaging (ARFI)-acoustic palpation tissue quantification (VTQ) technology, and strain elastography alone and their combination in diagnosis of benign and malignant thyroid micronodules.

Methods A retrospective analysis was conducted in 99 patients (107 thyroid micro-solid nodules with diameters ≤ 10.0 mm) who were treated at Baoji People's Hospital in Shaanxi Province from June 2021 to June 2023. All patients underwent two-dimensional high-frequency ultrasound, ARFI-VTQ technology, and strain elastography to obtain ultrasound data scores and data. Using biopsy and surgical pathology as the diagnostic "gold standard", the diagnostic efficacy of the three ultrasound methods alone and their combination was compared for thyroid micro-nodules.

Results A total of 62 patients (68 nodules) underwent fine-needle aspiration biopsy (FNAB), and 37 patients (39 nodules) underwent surgery. Among 107 thyroid micro-nodules, 45 were diagnosed as malignant, and 62 as benign. Significant differences were observed between malignant micro-nodules and benign micro-nodules in terms of internal echo (isoechoic and hyperechoic echo, very hypoechoic and hypoechoic echo), boundary, microcalcification, aspect ratio >1, blood supply, and resistance index (RI) of the artery (P < 0.05). When the critical value of the C-TIRADS score for diagnosing thyroid micro-nodules using two-dimensional high-frequency ultrasound was ≥ 2 points (C-TIRADS 4b), the diagnostic sensitivity was 73.33%, specificity was 79.03%, and the area under the curve (AUC) was 0.76295%CI, 0.670 to 0.839. In ARFI-VTQ technology, the SWV values ranged from 0.52 to 7.55 m/s, with an average of (2.62 ± 0.61) m/s. The mean SWV of malignant micro-nodules was (5.24±2.23) m/s, which was higher than (2.11±0.70) m/s of benign micro-nodules (t=10.258, P < 0.05). When the critical SWV value was 3.19 m/s, the diagnostic sensitivity was 77.78%, specificity was 80.65%, and the AUC (95%CI) was 0.792(95%CI, 0.703 to 0.865). In strain elastography, when the critical score was ≥3, the diagnostic sensitivity was 75.56%, specificity was 77.42%, and the AUC (95%CI) was 0.765 (95%CI, 0.673 to 0.841). Combined detection of the three methods showed that there were 44 positive micro-nodules, 63 negative micro-nodules, the diagnostic sensitivity was 93.33%, specificity was 96.77%, and the AUC (95%CI) was 0.951 (95%CI, 0.891 to 0.983). There was statistical significance in the diagnostic efficacy of combined application compared with that of 2D high-frequency ultrasonography, ARFI-VTQ technology and strain-elasticity imaging alone (Z=4.861, 4.393, 4.842, P < 0.05).

Conclusion The combination of two-dimensional high-frequency ultrasound, ARFI-VTQ technology, and strain elastography can improve the diagnostic accuracy of benign and malignant thyroid micro-nodules.