Department of Radiology & Nuclear Medicine, Erasmus MC, P.O. Box 2240, 3000 CA, Rotterdam, The Netherlands.
Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
Eur Radiol. 2020 Jun;30(6):3346-3355. doi: 10.1007/s00330-020-06709-9. Epub 2020 Feb 19.
To assess the dose reduction potential of a calcium-aware reconstruction technique, which aims at tube voltage-independent computed tomography (CT) numbers for calcium.
A cardiothoracic phantom, mimicking three different patient sizes, was scanned with two calcium inserts (named D100 and CCI), containing calcifications varying in size and density. Tube voltage was varied both manually (range 70-150 and Sn100 kVp) and automatically. Tube current was automatically adapted to maintain reference image quality defined at 120 kVp. Data was reconstructed with the standard reconstruction technique (kernel Qr36) and the calcium-aware reconstruction technique (kernel Sa36). We assessed the radiation dose reduction potential (volumetric CT dose index values (CTDIvol)), noise (standard deviation (SD)), mean CT number (HU) of each calcification, and Agatston scores for varying kVp. Results were compared with the reference acquired at 120 kVp and reconstructed with Qr36.
Automatic selection of the optimal tube voltage resulted in a CTDIvol reduction of 22%, 15%, and 12% compared with the reference for the small, medium, and large phantom, respectively. CT numbers differed up to 64% for the standard reconstruction and 11% for the calcium-aware reconstruction. Similarly, Agatston scores deviated up to 40% and 8% for the standard and calcium-aware reconstruction technique, respectively.
CT numbers remained consistent with comparable calcium scores when the calcium-aware image reconstruction technique was applied with varying tube voltage. Less consistency was observed in small calcifications with low density. Automatic reduction of tube voltage resulted in a dose reduction of up to 22%.
• The calcium-aware image reconstruction technique allows for consistent CT numbers when varying the tube voltage. • Automatic reduction of tube voltage results in a reduced radiation exposure of up to 22%. • This study stresses the known limitations of the current Agatston score technique.
评估一种钙感知重建技术的剂量降低潜力，该技术旨在实现管电压独立的 CT 号（CT 号）用于钙。
使用两个钙插入物（分别命名为 D100 和 CCI）模拟三种不同患者体型的心胸体模，该插入物含有大小和密度不同的钙化。手动（范围为 70-150 和 Sn100 kVp）和自动改变管电压。自动调节管电流以保持在 120 kVp 定义的参考图像质量。数据采用标准重建技术（内核 Qr36）和钙感知重建技术（内核 Sa36）进行重建。我们评估了不同管电压下的辐射剂量降低潜力（容积 CT 剂量指数值（CTDIvol））、噪声（标准差（SD））、每个钙化的平均 CT 号（HU）和 Agatston 评分。结果与在 120 kVp 获得并采用 Qr36 重建的参考值进行了比较。
与参考值相比，自动选择最佳管电压可使小型、中型和大型体模的 CTDIvol 分别降低 22%、15%和 12%。标准重建的 CT 号差异最大可达 64%，钙感知重建的 CT 号差异最大可达 11%。同样，Agatston 评分的差异在标准和钙感知重建技术中分别最大可达 40%和 8%。
当应用变管电压的钙感知图像重建技术时，CT 号保持一致，同时具有可比的钙评分。在密度较低的小钙化中观察到一致性较低。自动降低管电压可使剂量降低高达 22%。
钙感知图像重建技术允许在改变管电压时保持一致的 CT 号。
自动降低管电压可使辐射暴露减少高达 22%。
本研究强调了当前 Agatston 评分技术的已知局限性。
