Department of Radiology, Ansan Hospital, Korea University College of Medicine, 123, Jeokgeum-ro, Danwon-gu, Ansan-si, Gyeonggi-do, 15355, Republic of Korea.
Department of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Jpn J Radiol. 2021 Jun;39(6):580-588. doi: 10.1007/s11604-021-01095-8. Epub 2021 Jan 28.
Although virtual non-contrast (VNC) successfully removes iodinated contrast, uncertainty exists regarding the feasibility of VNC to suppress iodine for detecting thyroid calcification. Therefore, we evaluated whether both intrinsic and extrinsic iodine attenuation were suppressed on VNC images.
We enrolled 128 patients (male: female 17:111; age 48.0 ± 10.4 years) who underwent dual-layer dual-energy CT (DL-DECT) examination before their thyroid cancer surgeries. Two additional sets of VNC (VNCu, VNCc) images were retrospectively generated from their true unenhanced (TUE) and true contrast-enhanced (TCE) series. We compared CT attenuation values measured on the VNCu and VNCc images by drawing identical regions of interest encompassing thyroid parenchyma, then subjectively determined the concordance of calcification.
Although CT attenuation discrepancies between the VNCu and VNCc were significant (2.0 ± 5.7HU, p < 0.001),61.7%, 89.1%, and 100.0% of all measurements were < 5HU, < 10HU, and < 15HU. Based on Bland-Altman analysis, the limits of agreement were - 9.2HU and 13.2HU, whereas the proportional differences were small for VNC images generated from both TUE and TCE images. There was no discordance between two VNC image sets in detecting thyroid calcification.
VNC technique could be a feasible method to suppress both intrinsic and extrinsically administered iodine for detecting thyroid calcification.
虽然虚拟非对比（VNC）可以成功去除碘对比剂，但对于 VNC 是否能够抑制碘以检测甲状腺钙化仍存在不确定性。因此，我们评估了 VNC 图像是否同时抑制了内源性和外源性碘衰减。
我们纳入了 128 名（男：女 17:111；年龄 48.0±10.4 岁）在甲状腺癌手术前接受双层双能 CT（DL-DECT）检查的患者。从他们的真实未增强（TUE）和真实增强（TCE）系列中，我们分别回顾性生成了两组 VNC（VNCu、VNCc）图像。我们通过在甲状腺实质中绘制相同的感兴趣区来比较 VNCu 和 VNCc 图像上的 CT 衰减值，然后主观判断钙化的一致性。
虽然 VNCu 和 VNCc 之间的 CT 衰减差异具有统计学意义（2.0±5.7HU，p<0.001），但所有测量值中有 61.7%、89.1%和 100.0%均<5HU、<10HU 和<15HU。基于 Bland-Altman 分析，一致性界限为-9.2HU 和 13.2HU，而 TUE 和 TCE 图像生成的 VNC 图像的比例差异较小。两种 VNC 图像在检测甲状腺钙化方面没有不一致。
VNC 技术可能是一种可行的方法，可以同时抑制内源性和外源性碘来检测甲状腺钙化。
