尽管2018年肝脏成像报告和数据系统（LI-RADS）修订了阈值生长（TG），但尚未确定TG两次检查之间的适当时间间隔。我们比较了基于肿瘤生长速率的TG和原始TG的LI-RADS v2018对肝细胞癌（HCC）的诊断准确性。回顾性评估了接受术前MRI检查的局灶性实性病变（≤3.0 cm）的患者。三名阅片医师测量了先前CT/MRI和索引MRI上每个病变的大小，肿瘤生长速率定义为每月病变大小的百分数变化。除了原始TG（≥50%的大小增加在≤6个月内），还评估了基于肿瘤生长速率≥10%/月（TG-10%）、≥20%/月（TG-20%）和≥30%/月（TG-30%）的修改TG。使用广义估计方程比较了这些评估方法对LI-RADS 5级HCC的准确性。 共评估了370名患者的508个病变。与带有原始TG的LI-RADS v2018相比，LI-RADS带有TG-10%的准确性显著更高（85.0% vs. 80.7%，p<.001），而LI-RADS带有TG-20%（81.3% vs. 80.7%，p=.404）和TG-30%（79.3% vs. 80.7%，p=.052）的准确性没有显著差异。LI-RADS带有TG-10%的敏感性高于LI-RADS v2018（79.0% vs. 72.5%，p<.001），而它们的特异性没有显著差异（96.6% vs. 96.6%，p>.999）。TG-10%通过检测由于短期随访而低估的额外肝细胞癌，提高了LI-RADS的敏感性。基于肿瘤生长速率的阈值生长在肝细胞癌的诊断中具有临床应用价值，可通过提高LI-RADS的敏感性来改善诊断准确性。 • 先前和索引评估之间的时间间隔对肝脏成像报告和数据系统（LI-RADS）v2018的诊断准确性没有显著影响。 • 在334个肝细胞癌中，使用肿瘤生长速率≥10%/月（TG-10%）的阈值生长频率显著高于原始阈值生长（53.3% vs. 18.0%，p<.001）。 • 与带有原始阈值生长的LI-RADS v2018相比，带有TG-10%的LI-RADS的准确性（85.0% vs. 80.7%，p<.001）和敏感性（79.0% vs. 72.5%，p<.001）显著更高，但特异性相似（96.6% vs. 96.6%，p>.999）。 © 2023. 作者（们）在欧洲放射学会独家许可下发表。

Despite the revision of threshold growth (TG) in the Liver Imaging Reporting and Data System (LI-RADS) version 2018, the appropriate time period between the two examinations for TG has not been determined. We compared the accuracy of LI-RADS with TG based on tumor growth rate for the diagnosis of hepatocellular carcinoma (HCC) with that of LI-RADS v2018 based on the original TG.Patients who underwent preoperative MRI for focal solid lesions (≤ 3.0 cm) were retrospectively evaluated. Three readers measured the size of each lesion on prior CT/MRI and index MRI, with tumor growth rate defined as the percent change in lesion size per month. In addition to the original TG (≥ 50% size increase within ≤ 6 months), the modified TG based on tumor growth rates ≥ 10%/month (TG-10%), ≥ 20%/month (TG-20%), and ≥ 30%/month (TG-30%) were evaluated. The accuracies of these evaluation methods for LI-RADS category 5 HCC were compared using generalized estimation equations.A total of 508 lesions from 370 patients were evaluated. Compared with LI-RADS v2018 with the original TG, the accuracy of LI-RADS with TG-10% was significantly higher (85.0% vs. 80.7%, p < .001), whereas the accuracies of LI-RADS with TG-20% (81.3% vs. 80.7%, p = .404) and TG-30% (79.3% vs. 80.7%, p = .052) were not significant. The sensitivity of LI-RADS with TG-10% was higher than that of LI-RADS v2018 (79.0% vs. 72.5%, p < .001), whereas their specificities were not significantly different (96.6% vs. 96.6%, p > .999).TG-10% improved the sensitivity of LI-RADS by detecting additional hepatocellular carcinomas underestimated due to short-term follow-up.Threshold growth based on tumor growth rate can be clinically useful in the diagnosis of hepatocellular carcinoma, by improving the sensitivity of LI-RADS.• The diagnostic accuracy of Liver Imaging Reporting and Data System (LI-RADS) v2018 was not significantly affected by the time interval between prior and index assessments of threshold growth. • In the 334 hepatocellular carcinomas, the frequency of threshold growth was significantly higher using tumor growth rate ≥ 10%/month (TG-10%) than original threshold growth (53.3% vs. 18.0%, p < .001). • Compared with LI-RADS v2018 with the original threshold growth, LI-RADS with TG-10% had significantly higher accuracy (85.0% vs. 80.7%, p < .001) and sensitivity (79.0% vs. 72.5%, p < .001) but a similar specificity (96.6% vs. 96.6%, p > .999).© 2023. The Author(s), under exclusive licence to European Society of Radiology.