1 Department of Radiology, Stanford University School of Medicine, Stanford, CA.
2 Department of Radiology, Division of Abdominal Imaging, Duke University Medical Center, Box 3808 Erwin Rd, Durham, NC 27710.
AJR Am J Roentgenol. 2018 Sep;211(3):571-579. doi: 10.2214/AJR.17.19170. Epub 2018 Jul 24.
The objective of this study is to determine whether single-phase contrast-enhanced dual-energy CT (DECT) material attenuation analysis improves the characterization of small (< 2.0 cm) incidental indeterminate hypoattenuating hepatic lesions, compared with conventional single-energy CT evaluation.
This retrospective study involved 55 patients (24 men and 31 women; mean [± SD] age, 63.9 ± 15.3 years) with 77 incidental hypoattenuating hepatic lesions (59 benign and 18 malignant lesions) measuring 0.5-2.0 cm who underwent single-phase contrast-enhanced DECT of the abdomen for pain. For each lesion, attenuation measurements were obtained using blended 120-kVp-equivalent images and contrast map images. DECT material attenuation images were used for iodine quantification. Optimal lesion attenuation and iodine concentration threshold values that best distinguished benign lesions from malignant lesions were generated using smooth bootstrapping. The diagnostic accuracy of the optimized thresholds was compared using the Wilcox rank sum test.
The optimal mean (± standard error) attenuation threshold values that best differentiated benign and malignant lesions were 50.2 ± 5.2 HU and 11.5 ± 2.0 HU when blended 120-kVp and contrast map images, respectively, were used. The iodine concentration (expressed as milligrams of iodine per milliliter) differed significantly (p < 0.0001) between benign lesions (0.6 ± 0.4 mg I/mL) and malignant lesions (1.7 ± 0.4 mg I/mL). The optimal iodine concentration that best distinguished between benign and malignant lesions was 1.2 ± 0.1 mg I/mL. The sensitivity, specificity, and AUC value were highest for iodine concentration (0.94, 0.93, and 0.97, respectively), compared with blended images (0.89, 0.70, and 0.81, respectively) and contrast map images (0.94, 0.64, 0.77, respectively).
Iodine quantification performed using single-phase contrast-enhanced DECT material attenuation images improves the characterization of small (< 2 cm) incidental indeterminate hypoattenuating hepatic lesions, compared with conventional attenuation measurements.
本研究旨在确定单期增强双能 CT（DECT）物质衰减分析是否优于常规单能 CT 评估，从而提高对小（<2.0cm）偶然不定性低衰减肝病变的特征描述。
本回顾性研究纳入了 55 名（男 24 名，女 31 名；平均[±标准差]年龄，63.9±15.3 岁）接受腹部单期增强 DECT 检查以治疗疼痛的 77 个偶然发现的低衰减肝病变（59 个良性病变和 18 个恶性病变）患者。对每个病变，使用混合 120kVp 等效图像和对比图图像进行衰减测量。DECT 物质衰减图像用于碘定量。使用平滑引导生成最佳病变衰减和碘浓度阈值，以最佳区分良性和恶性病变。使用 Wilcox 秩和检验比较优化阈值的诊断准确性。
当使用混合 120kVp 和对比图图像时，最佳的平均（±标准误差）区分良性和恶性病变的衰减阈值分别为 50.2±5.2HU 和 11.5±2.0HU。良性病变（0.6±0.4mgI/mL）和恶性病变（1.7±0.4mgI/mL）之间的碘浓度（以每毫升毫克碘表示）差异显著（p<0.0001）。最佳碘浓度（1.2±0.1mgI/mL）可最佳区分良性和恶性病变。与混合图像（分别为 0.89、0.70 和 0.81）和对比图图像（分别为 0.94、0.64 和 0.77）相比，碘浓度的灵敏度、特异性和 AUC 值最高（分别为 0.94、0.93 和 0.97）。
与常规衰减测量相比，使用单期增强 DECT 物质衰减图像进行碘定量可提高对小（<2cm）偶然不定性低衰减肝病变的特征描述。
