Yang Yanhui, Hou Jing, Niu Yue, Zhang Yi, Luo Tao, Lu Qiang, Fu Yi, Wang Yu, Yu Xiaoping
Department of Diagnostic Radiology, Graduate Collaborative Training Base of Hunan Cancer Hospital, Hengyang Medical School, University of South China, Hengyang, China.
Department of Diagnostic Radiology, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China.
Quant Imaging Med Surg. 2024 Jun 1;14(6):3803-3815. doi: 10.21037/qims-23-1543. Epub 2024 Apr 12.
Virtual non-calcium (VNCa) imaging based on dual-energy computed tomography (CT) plays an increasingly important role in diagnosing spinal diseases. However, the utility of VNCa technology in the measurement of vertebral bone mineral density (BMD) is limited, especially the VNCa CT value at multiple calcium suppression levels and the slope of VNCa curve. This retrospective cross-sectional study aimed to explore the correlation between vertebral BMD and new VNCa parameters from dual-layer spectral detector CT.
The dual-layer spectral detector CT and quantitative CT (QCT) data of 4 hydroxyapatite (HAP) inserts and 667 vertebrae of 234 patients (132 male and 102 female) who visited a university teaching hospital between April and May 2023 were retrospectively analyzed. The BMD values of 3 vertebrae (T12, L1, and L2) and inserts were measured using QCT, defined as QCT-BMD. The VNCa CT values and the slope λ of the VNCa attenuation curve of vertebrae and inserts were recorded. The correlations between VNCa parameters (VNCa CT value, slope λ) and QCT-BMD were analyzed.
For the vertebrae, the correlation coefficient ranged from -0.904 to 0.712 (all P<0.05). As the calcium suppression index (CaSI) increased, the correlation degree exhibited a decrease first and then increased, with the best correlation (r=-0.904, P<0.001) observed at the index of 25%. In contrast, the correlation coefficient for the inserts remained relatively stable (r=-0.899 to -1, all P<0.05). For the vertebrae, the values of 3 slopes λ (λ1, λ2, and λ3) derived from the VNCa attenuation curve were 6.50±1.99, 3.75±1.15, and 2.04±0.62, respectively. Regarding the inserts, the λ1, λ2, and λ3 values were 11.56 [interquartile range (IQR): 2.40-22.62], 6.68 (IQR: 1.39-13.49), and 3.63 (IQR: 0.75-7.8), respectively. For the vertebrae, all 3 correlation coefficients between 3 slopes λ and QCT-BMD were 0.956 (all P<0.05). For the inserts, the 3 correlation coefficients were 0.996, 0.998, and 1 (all P<0.05), respectively.
A promising correlation was detected between VNCa CT parameters and QCT-BMD in vertebrae, warranting further investigation to explore the possibility of VNCa imaging to assess BMD.
基于双能计算机断层扫描（CT）的虚拟非钙（VNCa）成像在脊柱疾病诊断中发挥着越来越重要的作用。然而，VNCa技术在测量椎体骨密度（BMD）方面的效用有限，尤其是在多个钙抑制水平下的VNCa CT值以及VNCa曲线的斜率。这项回顾性横断面研究旨在探讨双层光谱探测器CT中椎体BMD与新的VNCa参数之间的相关性。
回顾性分析了2023年4月至5月期间在某大学教学医院就诊的234例患者（132例男性和102例女性）的4个羟基磷灰石（HAP）植入物和667个椎体的双层光谱探测器CT及定量CT（QCT）数据。使用QCT测量3个椎体（T12、L1和L2）及植入物的BMD值，定义为QCT - BMD。记录椎体和植入物的VNCa CT值以及VNCa衰减曲线的斜率λ。分析VNCa参数（VNCa CT值、斜率λ）与QCT - BMD之间的相关性。
对于椎体，相关系数范围为 - 0.904至0.712（所有P<0.05）。随着钙抑制指数（CaSI）增加，相关程度先降低后升高，在指数为25%时观察到最佳相关性（r = - 0.904，P<0.001）。相比之下，植入物的相关系数保持相对稳定（r = - 0.899至 - 1，所有P<0.05）。对于椎体，从VNCa衰减曲线得出的3个斜率λ（λ1、λ2和λ3）值分别为6.50±1.99、3.75±1.15和2.04±0.62。对于植入物，λ1、λ2和λ3值分别为11.56[四分位数间距（IQR）：2.40 - 22.62]、6.68（IQR：1.39 - 13.49）和3.63（IQR：0.75 - 7.8）。对于椎体，3个斜率λ与QCT - BMD之间的所有3个相关系数均为0.956（所有P<0.05）。对于植入物，3个相关系数分别为0.996、0.998和1（所有P<0.05）。
在椎体中检测到VNCa CT参数与QCT - BMD之间存在有前景的相关性，值得进一步研究以探索VNCa成像评估BMD的可能性。
