Role of CT in predicting capsular invasion and cervical lymph node metastasis in papillary thyroid carcinoma / 中华放射学杂志

ABSTRACT

Objective:To investigate the value of CT tumor-thyroid marginal contact range (MCR) for predicting capsular invasion and cervical lymph node metastasis in papillary thyroid carcinoma (PTC) with a diameter>1.0 cm and papillary thyroid microcarcinomas (PTMC) with a diameter ≤ 1.0 cm, and to evaluate the diagnostic efficacy of direct CT signs for lymph node metastasis.Methods:The CT data of 148 patients with PTC (>1.0 cm) and 193 patients with PTMC confirmed by surgery and pathology were retrospectively analyzed from January 2017 to April 2020 at Hangzhou First People′s Hospital. MCR was evaluated based on CT images and classified as<1/4 tumor circumference or ≥1/4 tumor circumference. Direct CT signs of cervical lymph nodes were observed, including cystic change, microcalcification, hyperenhancement, short/long diameter≥0.5, clustered lymph nodes or central area turbidity. The difference in the distribution of MCR between PTC (>1.0 cm) and PTMC was compared using the χ 2 test, and the efficiency of MCR and direct CT signs for diagnosing capsular invasion and lymph node metastasis was calculated using the pathological results as the gold standard. Results:In 148 PTC (>1.0 cm) and 193 PTMC patients, the pathological results showed capsular invasion in 88.5% (131/148) and 57.0% (110/193), and lymph node metastasis in 71.6% (106/148) and 44.0% (85/193), respectively. In PTC (>1.0 cm) patients, MCR≥1/4 tumor circumference was more common in patients with capsular invasion (χ2=22.211, P<0.001) and lymph node metastasis (χ2=4.746, P=0.029), and the corresponding sensitivity and specificity for predicting capsular invasion and lymph node metastasis were 84.7% (111/131) and 64.7% (11/17), 83.0% (88/106) and 33.3% (14/42), respectively. In PTMC patients, MCR≥1/4 tumor circumference was more common in patients with capsular invasion (χ2=66.066, P<0.001) and lymph node metastasis (χ2=5.343, P=0.021), and its sensitivity and specificity for predicting capsular invasion and lymph node metastasis were 87.3% (96/110) and 69.9% (58/83), 71.8% (61/85) and 44.4% (48/108), respectively. The sensitivity and specificity of direct CT signs for diagnosing lymph node metastasis in PTC (>1.0 cm) and PTMC were 89.6% and 73.8%, 69.4% and 76.9%, respectively. Conclusions:Both direct CT signs and MCR ≥ 1/4 tumor circumference can predict cervical lymph node metastasis in PTC patients, and the former had higher sensitivity and specificity. MCR≥1/4 tumor circumference has high efficiency for predicting capsular invasion in PTC patients.