Department of Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Str. 62, 50937, Cologne, Germany.
Else Kröner Forschungskolleg Clonal Evolution in Cancer, University Hospital Cologne, Weyertal 115b, 50931, Cologne, Germany.
Cancer Imaging. 2019 Jul 17;19(1):50. doi: 10.1186/s40644-019-0235-3.
To investigate if iodine density overlay maps (IDO) and virtual monoenergetic images at 40 keV (VMI) acquired from spectral detector computed tomography (SDCT) can improve detection of incidental skeletal muscle metastases in whole-body CT staging examinations compared to conventional images.
In total, 40 consecutive cancer patients who underwent clinically-indicated, contrast-enhanced, oncologic staging SDCT were included at this retrospective study: 16 patients with n = 108 skeletal muscle metastases confirmed by prior or follow-up CT, F-FDG-PET, MRI or histopathology, and a control group of 24 patients without metastases. Four independent readers performed blinded, randomized visual detection of skeletal muscle metastases in conventional images, IDO and VMI, indicating diagnostic certainty for each lesion on a 5-point Likert scale. Quantitatively, ROI-based measurements of attenuation (HU) in conventional images and VMI and iodine concentration in IDO were conducted. CNR was calculated and receiver operating characteristics (ROC) analysis of quantitative parameters was performed.
Regarding subjective assessment, IDO (63.2 (58.5-67.8) %) and VMI (54.4 (49.6-59.2) %) showed an increased sensitivity for skeletal muscle metastases compared to conventional images (39.8 (35.2-44.6) %). Specificity was comparable in VMI (69.8 (63.2-75.8) %) and conventional images (69.2 (60.6-76.9) %), while in IDO, it was moderately increased to 74.2 (65.3-78.4) %. Quantitative image analysis revealed that CNR of skeletal muscle metastases to circumjacent muscle was more than doubled in VMI (25.8 ± 11.1) compared to conventional images (10.0 ± 5.3, p ≤ 0.001). Iodine concentration obtained from IDO and HU acquired from VMI (AUC = 0.98 each) were superior to HU attenuation in conventional images (AUC = 0.94) regarding differentiation between healthy and metastatic muscular tissue (p ≤ 0.05).
IDO and VMI provided by SDCT improve diagnostic accuracy in the assessment of incidental skeletal muscle metastases compared to conventional CT.
为了研究碘密度叠加图（IDO）和虚拟单能量图像（VMI）在光谱探测器 CT（SDCT）中是否可以提高全身 CT 分期检查中偶然发现的骨骼肌转移的检测，与传统图像相比。
本回顾性研究共纳入 40 例连续接受临床指征、对比增强、肿瘤分期 SDCT 的癌症患者：16 例患者 n=108 例经先前或随访 CT、F-FDG-PET、MRI 或组织病理学证实的骨骼肌转移，对照组 24 例无转移患者。4 名独立读者对常规图像、IDO 和 VMI 中的骨骼肌转移进行了盲法、随机视觉检测，并对每个病变进行了 5 分李克特量表的诊断确定性。定量地，在常规图像和 VMI 中进行了 ROI 基础衰减（HU）测量和 IDO 中的碘浓度测量。计算了 CNR，并对定量参数进行了接收器工作特征（ROC）分析。
在主观评估方面，与常规图像（39.8（35.2-44.6）%）相比，IDO（63.2（58.5-67.8）%）和 VMI（54.4（49.6-59.2）%）对骨骼肌转移的敏感性增加。VMI（69.8（63.2-75.8）%）和常规图像（69.2（60.6-76.9）%）的特异性相当，而 IDO 则适度增加至 74.2（65.3-78.4）%）。定量图像分析显示，与常规图像（10.0±5.3，p≤0.001）相比，VMI 中骨骼肌转移到周围肌肉的 CNR 增加了一倍以上（25.8±11.1）。从 IDO 获得的碘浓度和从 VMI 获得的 HU（AUC 分别为 0.98）在区分健康和转移性肌肉组织方面优于常规图像中的 HU 衰减（AUC 分别为 0.94，p≤0.05）。
与常规 CT 相比，SDCT 提供的 IDO 和 VMI 可提高偶然发现的骨骼肌转移评估的诊断准确性。
