University Cologne, Faculty of Medicine and University Hospital Cologne, Department of Diagnostic and Interventional Radiology, Kerpener Straße 62, 50937, Cologne, Germany.
University Cologne, Faculty of Medicine and University Hospital Cologne, Department of Diagnostic and Interventional Radiology, Kerpener Straße 62, 50937, Cologne, Germany; Department of Radiology, Case Western Reserve University and University Hospitals, 11100 Euclid Ave, Cleveland, Ohio, USA.
Eur J Radiol. 2019 Jul;116:135-143. doi: 10.1016/j.ejrad.2019.05.003. Epub 2019 May 6.
To compare objective and subjective image quality between low keV virtual monoenergetic images (VMI) of the excretory phase and conventional venous phase images derived from spectral dual-energy CT (DECT) in the assessment of urothelial carcinoma.
26 consecutive patients with histologically confirmed urothelial carcinoma who received clinically indicated venous- and excretory phase abdominal CT scans were included retrospectively. Attenuation, image noise as well as signal- and contrast-to-noise-ratio (SNR, CNR) in venous and excretory phase CT and excretory phase VMI from 40 to 70 keV were obtained from ROI-based measurements in the following regions: urothelial carcinoma, liver, pancreas, renal cortex, subcutaneous fat, renal vein/artery, portal vein, urinary bladder wall, lymph nodes, prostate/uterus. Subjective vessel contrast and delineation of primary tumor manifestations and distant metastases were rated on 5-point Likert scales.
In comparison to venous phase CT, attenuation and SNR in excretory phase VMI40keV were higher (p < 0.001), except for liver parenchyma, where they were comparable (p = 0.07 and p = 0.17, respectively). Regarding image noise, no significant difference was found between venous phase CT and excretory phase VMI40keV (p-range: 0.08-1.00), except for liver, portal vein and renal artery, where it was lower in VMI40keV (p < 0.05). CNR of urothelial carcinoma to circumjacent bladder wall was significantly higher in excretory phase VMI40keV compared to venous phase CT. Subjective vessel contrast and delineation of primary tumor and distant metastases received equivalent or higher Likert scores in excretory phase VMI40keV than in venous phase CT.
This feasibility study indicates that in the assessment of urothelial carcinoma, virtual monoenergetic excretory phase images at 40 keV acquired with spectral DECT could be feasible to maintain subjective and objective image quality as provided by conventional venous phase images. Still, equivalence with regards to metastatic lesion detection requires further investigation before employing this technique in a potential signal-scan, single-bolus approach.
比较排泄期低 keV 虚拟单能量图像（VMI）与能谱双源 CT（DECT）常规静脉期图像在评估尿路上皮癌中的客观和主观图像质量。
回顾性纳入 26 例经组织学证实的尿路上皮癌患者，这些患者均接受了临床推荐的腹部静脉期和排泄期 CT 扫描。从 ROI 测量中获得了静脉期和排泄期 CT 以及 40 至 70keV 的排泄期 VMI 的衰减、图像噪声以及静脉期和排泄期的 SNR 和 CNR：尿路上皮癌、肝脏、胰腺、肾皮质、皮下脂肪、肾静脉/动脉、门静脉、膀胱壁、淋巴结、前列腺/子宫。使用 5 分制 Likert 量表对主要肿瘤表现和远处转移的血管对比度和勾画进行主观评分。
与静脉期 CT 相比，排泄期 VMI40keV 的衰减和 SNR 更高（p<0.001），除了肝脏，两者之间没有差异（p=0.07 和 p=0.17）。关于图像噪声，除了肝脏、门静脉和肾动脉外，静脉期 CT 与排泄期 VMI40keV 之间没有显著差异（p 值范围：0.08-1.00），VMI40keV 的图像噪声更低（p<0.05）。与静脉期 CT 相比，排泄期 VMI40keV 尿路上皮癌与周围膀胱壁的 CNR 显著更高。在排泄期 VMI40keV 中，血管对比度和对原发肿瘤及远处转移的勾画的主观评分与静脉期 CT 相同或更高。
这项可行性研究表明，在评估尿路上皮癌时，光谱 DECT 获得的排泄期 40keV 虚拟单能量图像在保持主观和客观图像质量方面可与常规静脉期图像相媲美。然而，在采用这种技术进行潜在的信号扫描、单剂量扫描之前，还需要进一步研究以确保其在转移性病变检测方面的等效性。
