低剂量计算机断层扫描检测肝脏低对比度病变的前瞻性评估：与同期标准剂量成像的直接比较
Prospective Evaluation of Reduced Dose Computed Tomography for the Detection of Low-Contrast Liver Lesions: Direct Comparison with Concurrent Standard Dose Imaging.
作者信息
Pooler B Dustin, Lubner Meghan G, Kim David H, Chen Oliver T, Li Ke, Chen Guang-Hong, Pickhardt Perry J
机构信息
Department of Radiology, University of Wisconsin School of Medicine and Public Health, 750 Highland Avenue, Madison, WI, 53705, USA.
Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, 750 Highland Avenue, Madison, WI, 53705, USA.
出版信息
Eur Radiol. 2017 May;27(5):2055-2066. doi: 10.1007/s00330-016-4571-4. Epub 2016 Sep 5.
OBJECTIVES
To prospectively compare the diagnostic performance of reduced-dose (RD) contrast-enhanced CT (CECT) with standard-dose (SD) CECT for detection of low-contrast liver lesions.
METHODS
Seventy adults with non-liver primary malignancies underwent abdominal SD-CECT immediately followed by RD-CECT, aggressively targeted at 60-70 % dose reduction. SD series were reconstructed using FBP. RD series were reconstructed with FBP, ASIR, and MBIR (Veo). Three readers-blinded to clinical history and comparison studies-reviewed all series, identifying liver lesions ≥4 mm. Non-blinded review by two experienced abdominal radiologists-assessing SD against available clinical and radiologic information-established the reference standard.
RESULTS
RD-CECT mean effective dose was 2.01 ± 1.36 mSv (median, 1.71), a 64.1 ± 8.8 % reduction. Pooled per-patient performance data were (sensitivity/specificity/PPV/NPV/accuracy) 0.91/0.78/0.60/0.96/0.81 for SD-FBP compared with RD-FBP 0.79/0.75/0.54/0.91/0.76; RD-ASIR 0.84/0.75/0.56/0.93/0.78; and RD-MBIR 0.84/0.68/0.49/0.92/0.72. ROC AUC values were 0.896/0.834/0.858/0.854 for SD-FBP/RD-FBP/RD-ASIR/RD-MBIR, respectively. RD-FBP (P = 0.002) and RD-MBIR (P = 0.032) AUCs were significantly lower than those of SD-FBP; RD-ASIR was not (P = 0.052). Reader confidence was lower for all RD series (P < 0.001) compared with SD-FBP, especially when calling patients entirely negative.
CONCLUSIONS
Aggressive CT dose reduction resulted in inferior diagnostic performance and reader confidence for detection of low-contrast liver lesions compared to SD. Relative to RD-ASIR, RD-FBP showed decreased sensitivity and RD-MBIR showed decreased specificity.
KEY POINTS
• Reduced-dose CECT demonstrates inferior diagnostic performance for detecting low-contrast liver lesions. • Reader confidence is lower with reduced-dose CECT compared to standard-dose CECT. • Overly aggressive dose reduction may result in misdiagnosis, regardless of reconstruction algorithm. • Careful consideration of perceived risks versus benefits of dose reduction is crucial.
目的
前瞻性比较低剂量（RD）对比增强CT（CECT）与标准剂量（SD）CECT检测肝脏低对比度病变的诊断性能。
方法
70例非肝脏原发性恶性肿瘤的成人患者先接受腹部SD-CECT检查，随后立即进行RD-CECT检查，积极将剂量降低60-70%。SD系列采用滤波反投影（FBP）重建。RD系列分别采用FBP、自适应统计迭代重建（ASIR）和基于模型的迭代重建（MBIR，Veo）进行重建。三位对临床病史和对比研究不知情的阅片者对所有系列进行阅片，识别直径≥4mm的肝脏病变。由两位经验丰富的腹部放射科医生根据现有临床和影像学信息对SD系列进行非盲法评估，以此确立参考标准。
结果
RD-CECT的平均有效剂量为2.01±1.36mSv（中位数为1.71），降低了64.1±8.8%。每位患者的汇总性能数据（灵敏度/特异度/阳性预测值/阴性预测值/准确度），SD-FBP为0.91/0.78/0.60/0.96/0.81，而RD-FBP为0.79/0.75/0.54/0.91/0.76；RD-ASIR为0.84/0.75/0.56/0.93/0.78；RD-MBIR为0.84/0.68/0.49/0.92/0.72。SD-FBP/RD-FBP/RD-ASIR/RD-MBIR的ROC曲线下面积（AUC）值分别为0.896/0.834/0.858/0.854。RD-FBP（P=0.002）和RD-MBIR（P=0.032）的AUC显著低于SD-FBP；RD-ASIR则不然（P=0.052）。与SD-FBP相比，所有RD系列的阅片者信心均较低（P<0.001），尤其是在判定患者完全为阴性时。
结论
与SD相比，积极降低CT剂量导致检测肝脏低对比度病变的诊断性能和阅片者信心下降。相对于RD-ASIR，RD-FBP的灵敏度降低，RD-MBIR的特异度降低。
关键点
• 低剂量CECT在检测肝脏低对比度病变方面显示出较差的诊断性能。
• 与标准剂量CECT相比，低剂量CECT的阅片者信心较低。
• 无论采用何种重建算法，过度积极地降低剂量可能导致误诊。
• 仔细权衡降低剂量所感知的风险与益处至关重要。
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