Department of Radiology, Gil Medical Center, Gachon University College of Medicine, Incheon, Korea.
Department of Radiology, Ajou University Hospital, Ajou University School of Medicine, Suwon, Korea.
Korean J Radiol. 2020 Mar;21(3):280-289. doi: 10.3348/kjr.2019.0447.
To test the feasibility of non-contrast magnetic resonance imaging (MRI) in a sequential imaging study for characterizing computed tomography (CT)-detected arterial-enhancing nodules that do not washout in patients at risk of hepatocellular carcinoma (HCC).
In this retrospective study, 134 patients (mean age ± standard deviation, 56.8 ± 10.0 years) with 151 arterial enhancing-only nodules measuring up to 2 cm during multiphasic CT that were subsequently evaluated using gadoxetic acid-enhanced MRI in treatment-naïve at-risk patients from three tertiary referral centers were included. Tentative diagnostic criteria for HCC and hepatic malignancy were defined as the presence of one of eight MRI features favoring HCC in combinations of the following sequences: T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), T1-weighted dual gradient-echo in-phase and out-of-phase imaging (Dual-GRE), and hepatobiliary phase imaging (HBP). Typical hemangiomas and arterioportal shunts were excluded from the analysis. Diagnostic performance for HCC and hepatic malignancy was calculated and compared between the abbreviated MRI and full-sequence gadoxetic acid-enhanced MRI.
Of 151 nodules (mean size, 1.2 cm) 68 HCCs and 83 non-HCC benignities and malignancies were included. The combination of T2WI, DWI, and Dual-GRE showed per-lesion sensitivity, specificity, and accuracy of 88.2%, 90.4%, and 89.4%, respectively, comparable to those of full-sequence MRI. Applying the same sequence combination to diagnose hepatic malignancy had per-lesion sensitivity, specificity, and accuracy of 86.8%, 97.3%, and 92.1%. In nodules < 1 cm, adding HBP increased sensitivity by up to 13% without compromising the specificity or accuracy.
The non-contrast MRI protocol comprising T2WI, DWI, and Dual-GRE showed reasonable and comparable performance to full-sequence MRI for discriminating HCC and primary liver malignancies in CT-detected indeterminate arterial enhancing-only nodules in at-risk patients, and can be potentially used for sequential imaging in place of a full-sequence MRI. In nodules < 1 cm, HBP may still be needed to preserve sensitivity.
在一项连续影像学研究中，测试非对比磁共振成像（MRI）在特征描述 CT 检测到的、不呈环形强化的动脉增强结节中的可行性，这些结节在肝细胞癌（HCC）风险患者中不呈环形强化。
本回顾性研究纳入了来自 3 家三级转诊中心的 134 名治疗前 HCC 风险患者，这些患者在多期 CT 检查中发现最大直径为 2cm 的 151 个动脉增强仅有结节，随后使用钆塞酸增强 MRI 进行评估。暂定的 HCC 和肝恶性肿瘤诊断标准定义为在以下序列组合中存在 8 种 MRI 特征中的 1 种，提示 HCC：T2 加权成像（T2WI）、弥散加权成像（DWI）、T1 加权双梯度回波同相位和反相位成像（双梯度回波，Dual-GRE）和肝胆期成像（HBP）。分析中排除了典型的肝血管瘤和动静脉分流。计算并比较了简化 MRI 和全序列钆塞酸增强 MRI 对 HCC 和肝恶性肿瘤的诊断性能。
在 151 个结节（平均大小 1.2cm）中，纳入了 68 个 HCC 和 83 个非 HCC 良性和恶性肿瘤。T2WI、DWI 和 Dual-GRE 联合应用的病变检出率分别为 88.2%、90.4%和 89.4%，与全序列 MRI 相当。应用相同的序列组合诊断肝恶性肿瘤的病变检出率分别为 86.8%、97.3%和 92.1%。在结节直径<1cm 时，添加 HBP 可使敏感性提高 13%，而特异性和准确性不受影响。
非对比 MRI 方案包括 T2WI、DWI 和 Dual-GRE，在 CT 检测到的、不呈环形强化的动脉增强仅有结节中，对于区分 HCC 和原发性肝恶性肿瘤，与全序列 MRI 相比具有合理且相当的性能，可潜在用于替代全序列 MRI 的连续影像学检查。在结节直径<1cm 时，仍需要 HBP 以保持敏感性。
