B3OA, CNRS UMR 7052, U 1271 Inserm, University of Paris, Paris, France.
University of Lyon, INSA-Lyon, CNRS, Inserm, CREATIS UMR 5220, U1206, Lyon, France.
Eur Radiol Exp. 2022 Feb 22;6(1):10. doi: 10.1186/s41747-021-00261-x.
Dual-energy computed tomography has shown a great interest for musculoskeletal pathologies. Photon-counting spectral computed tomography (PCSCT) can acquire data in multiple energy bins with the potential to increase contrast, especially for soft tissues. Our objectives were to assess the value of PCSST to characterise cartilage and to extract quantitative measures of subchondral bone integrity.
Seven excised human knees (3 males and 4 females; 4 normal and 3 with osteoarthritis; age 80.6 ± 14 years, mean ± standard deviation) were scanned using a clinical PCSCT prototype scanner. Tomographic image reconstruction was performed after Compton/photoelectric decomposition. Virtual monoenergetic images were generated from 40 keV to 110 keV every 10 keV (cubic voxel size 250 × 250 × 250 μm). After selecting an optimal virtual monoenergetic image, we analysed the grey level histograms of different tissues and extracted quantitative measurements on bone cysts.
The optimal monoenergetic images were obtained for 60 keV and 70 keV. Visual inspection revealed that these images provide sufficient spatial resolution and soft-tissue contrast to characterise surfaces, disruption, calcification of cartilage, bone osteophytes, and bone cysts. Analysis of attenuation versus energy revealed different energy fingerprint according to tissues. The volumes and numbers of bone cyst were quantified.
Virtual monoenergetic images may provide direct visualisation of both cartilage and bone details. Thus, unenhanced PCSCT appears to be a new modality for characterising the knee joint with the potential to increase the diagnostic capability of computed tomography for joint diseases and osteoarthritis.
双能计算机断层扫描在肌肉骨骼病变方面显示出极大的兴趣。光子计数能谱计算机断层扫描（PCSCT）可以在多个能量bins 中获取数据，具有增加对比度的潜力，尤其是对软组织。我们的目标是评估 PCSCT 对软骨进行特征描述的价值，并提取亚软骨骨完整性的定量测量值。
使用临床 PCSCT 原型扫描仪对 7 个切除的人膝关节（3 名男性和 4 名女性；4 个正常，3 个骨关节炎；年龄 80.6 ± 14 岁，平均值 ± 标准差）进行扫描。康普顿/光电分解后进行断层图像重建。从 40 keV 到 110 keV 每 10 keV 生成虚拟单能量图像（体素大小 250 × 250 × 250 μm）。在选择最佳虚拟单能量图像后，我们分析了不同组织的灰度直方图，并提取了骨囊肿的定量测量值。
在 60 keV 和 70 keV 获得了最佳的单能量图像。视觉检查表明，这些图像提供了足够的空间分辨率和软组织对比度，可用于对软骨表面、软骨破坏、钙化、骨赘和骨囊肿进行特征描述。衰减与能量的分析表明，根据组织的不同，存在不同的能量特征。定量分析了骨囊肿的体积和数量。
虚拟单能量图像可能提供软骨和骨细节的直接可视化。因此，未增强的 PCSCT 似乎是一种新的膝关节成像方式，有可能提高计算机断层扫描对关节疾病和骨关节炎的诊断能力。
