Prakash Priyanka, Kalra Mannudeep K, Digumarthy Subba R, Hsieh Jiang, Pien Homer, Singh Sarabjeet, Gilman Matthew D, Shepard Jo-Anne O
Division of Thoracic Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
J Comput Assist Tomogr. 2010 Jan;34(1):40-5. doi: 10.1097/RCT.0b013e3181b26c67.
To assess radiation dose reduction and image quality for weight-based chest computed tomographic (CT) examination results reconstructed using adaptive statistical iterative reconstruction (ASIR) technique.
With local ethical committee approval, weight-adjusted chest CT examinations were performed using ASIR in 98 patients and filtered backprojection (FBP) in 54 weight-matched patients on a 64-slice multidetector CT. Patients were categorized into 3 groups: 60 kg or less (n = 32), 61 to 90 kg (n = 77), and 91 kg or more (n = 43) for weight-based adjustment of noise indices for automatic exposure control (Auto mA; GE Healthcare, Waukesha, Wis). Remaining scan parameters were held constant at 0.984:1 pitch, 120 kilovolts (peak), 40-mm table feed per rotation, and 2.5-mm section thickness. Patients' weight, scanning parameters, and CT dose index volume were recorded. Effective doses (EDs) were estimated. Image noise was measured in the descending thoracic aorta at the level of the carina. Data were analyzed using analysis of variance.
Compared with FBP, ASIR was associated with an overall mean (SD) decrease of 27.6% in ED (ASIR, 8.8 [2.3] mSv; FBP, 12.2 [2.1] mSv; P < 0.0001). With the use of ASIR, the ED values were 6.5 (1.8) mSv (28.8% decrease), 7.3 (1.6) mSv (27.3% decrease), and 12.8 (2.3) mSv (26.8% decrease) for the weight groups of 60 kg or less, 61 to 90 kg, and 91 kg or more, respectively, compared with 9.2 (2.3) mSv, 10.0 (2.0) mSv, and 17.4 (2.1) mSv with FBP (P < 0.0001). Despite dose reduction, there was less noise with ASIR (12.6 [2.9] mSv) than with FBP (16.6 [6.2] mSv; P < 0.0001).
Adaptive statistical iterative reconstruction helps reduce chest CT radiation dose and improve image quality compared with the conventionally used FBP image reconstruction.
评估使用自适应统计迭代重建（ASIR）技术重建的基于体重的胸部计算机断层扫描（CT）检查结果的辐射剂量降低情况和图像质量。
经当地伦理委员会批准，对98例患者使用ASIR进行体重调整后的胸部CT检查，对54例体重匹配的患者在64层多排CT上使用滤波反投影（FBP）。患者分为3组：体重60千克及以下（n = 32）、61至90千克（n = 77）、91千克及以上（n = 43），用于基于体重调整自动曝光控制（自动毫安；通用电气医疗集团，威斯康星州沃基沙）的噪声指数。其余扫描参数保持恒定，螺距为0.984:1，管电压120千伏（峰值），每旋转扫描床进床40毫米，层厚2.5毫米。记录患者体重、扫描参数和CT剂量指数容积。估算有效剂量（ED）。在隆突水平的降主动脉处测量图像噪声。使用方差分析对数据进行分析。
与FBP相比，ASIR使ED总体平均（标准差）降低27.6%（ASIR为8.8 [2.3] 毫希沃特；FBP为12.2 [2.1] 毫希沃特；P < 0.0001）。使用ASIR时，体重60千克及以下、61至90千克、91千克及以上组的ED值分别为6.5（1.8）毫希沃特（降低28.8%）、7.3（1.6）毫希沃特（降低27.3%）、12.8（2.3）毫希沃特（降低26.8%），而FBP组分别为9.2（2.3）毫希沃特、10.0（2.0）毫希沃特、17.4（2.1）毫希沃特（P < 0.0001）。尽管剂量降低，但ASIR的噪声（12.6 [2.9] 毫希沃特）低于FBP（16.6 [6.2] 毫希沃特；P < 0.0001）。
与传统使用的FBP图像重建相比，自适应统计迭代重建有助于降低胸部CT辐射剂量并提高图像质量。
