Uni and multi-variate analyses for ultrasonic signs of smaller than 5 mm nodules of multifocal papillary thyroid carcinoma

Abstract

To explore the ultrasonic signs of < 5 mm nodules of multifocal papillary thyroid carcinoma (MPTC) so as to boost its preoperative detection rate and lower its residual cancer and reoperative risk. The sonographic appearances of 251 suspicious nodules smaller than 5 mm in MPTC were retrospectively reviewed by univariate (Chi-square test) and multivariate analysis (logistic regression analysis). A total of 202 papillary thyroid microcarcinoma (PTMC) in MPTC were confirmed pathologically. Among 251 nodules, vague edge were found in 141 (69.8%) PTMCs and in 23 (46.9%) benign thyroid nodules (BTN), 193 (95.5%) PTMCs were solid while non echo areas were found in 23 (46.9%) BTNs, 191 (94.6%) PTMCs were low echo while 20 in BTNs (40.8%), 167 (82.7%) PTMCs were aspect ratio larger than 1 (L/S > 1) and 24 (49.0%) BTNs were L/S < 1, micro-calcifications were found in 40 (19.8%) PTMCs and in 9 (18.4%) BTNs, 44 (21.8%) PTMCs and 15 (30.6%) BTNs showed blood flow signal in nodules, surrounding echo halo about nodules were absent in 152 (75.2%) PTMCs but were found in 20 (40.8%) BTNs, 168 (83.2%) PTMCs and 37 (75.5%) BTNs elasticity score great than or equal to 3. Ill-defined margin, hypoechoic, solid composion, aspect ratio larger than 1 (L/S > 1) and absent of surrounding echo halo were reliable sonographic signs to indicate PTMC (P < 0.05) by univariate analysis. Hyperechoic spots and blood signals in nodules, elasticity score great than or equal to 3 show limited helpless in diagnosis of PTMC. 4 kinds of ultrasonic characteristics such as hypoechoic, solid composion, L/S > 1 and absent of surrounding echo halo are directly related to PTMC by multivariate analysis (P < 0.05). Uni and multi-variate analyses of ultrasonic signs for nodules < 5 mm may guide the preoperative diagnosis of MPTC.