Department of Radiology, Riga Stradin's University, Riga, Latvia.
Department of Radiology, Children's Clinical University Hospital, Riga, Latvia.
Acta Radiol. 2023 Sep;64(9):2618-2626. doi: 10.1177/02841851231185347. Epub 2023 Jul 19.
Iterative reconstruction techniques (IRTs) are commonly used in computed tomography (CT) and help to reduce image noise.
To determine the minimum radiation dose while preserving image quality in head CT using IRTs.
The anthropomorphic phantom was used to scan nine head CT image series with varied radiation parameters. CT dose parameters, including volume CT dose index (CTDIvol [in mGy]) and dose length product (DLP [in mGy/cm]), were recorded for each scan series. Different noise levels (iDoseL1-6) were used in IRT reconstructions for soft and bone tissues. In total, 15 measurements were taken from five regions of interest (ROI) with an area of 10 mm. The signal-to-noise ratio (SNR) and noise values obtained at different ROIs were compared among various reconstruction methods with repeated measures of statistical analysis
In the head CT scan, applying IRT iDoseL5 had the lowest noise and highest SNR for soft tissue ( < 0.05), and increased iDose can decrease CT dose by 54.6% without compromising image quality. While for bone tissue reconstruction, no clear association was found between the level of iDose and noise. However, when CTDIvol is >20 mGy, iDoseL4 is slightly superior to other reconstruction methods ( < 0.065).
Using IRTs in head CTs reduces radiation dose while maintaining image quality. IDoseL5 provided optimal balance for soft tissue.
迭代重建技术（IRTs）常用于计算机断层扫描（CT），有助于降低图像噪声。
在使用 IRT 的头部 CT 中确定在保持图像质量的同时降低最低辐射剂量。
使用人体模型扫描了九个具有不同辐射参数的头部 CT 图像系列。记录了每个扫描系列的 CT 剂量参数，包括容积 CT 剂量指数（CTDIvol[以 mGy 计]）和剂量长度乘积（DLP[以 mGy/cm 计]）。IRT 重建中针对软组织和骨组织使用了不同的噪声水平（iDoseL1-6）。总共在五个感兴趣区域（ROI）中进行了 15 次测量，每个 ROI 的面积为 10mm。使用重复测量的统计分析比较了不同重建方法中在不同 ROI 获得的信噪比（SNR）和噪声值。
在头部 CT 扫描中，应用 IRT iDoseL5 可使软组织的噪声最低、信噪比最高（<0.05），而增加 iDose 可在不影响图像质量的情况下将 CT 剂量降低 54.6%。对于骨组织重建，未发现 iDose 与噪声之间存在明显关联。然而，当 CTDIvol>20mGy 时，iDoseL4 略优于其他重建方法（<0.065）。
在头部 CT 中使用 IRT 可降低辐射剂量，同时保持图像质量。iDoseL5 为软组织提供了最佳的平衡。
