Department of Radiology and Diagnostic Imaging, Mater Misericordiae University Hospital, Dublin, Ireland.
Can Assoc Radiol J. 2010 Dec;61(5):258-64. doi: 10.1016/j.carj.2010.01.003. Epub 2010 Mar 2.
To study the impact of dose parameters on image quality at whole-body low-dose multidetector computed tomography (CT) in an attempt to derive parameters that allow diagnostic quality images of the skeletal system without incurring significant radiation dose in patients referred for investigation of plasma cell dyscrasias.
By using a single cadaver, 14 different whole-body low-dose CT protocols were individually assessed by 2 radiologists, blinded to acquisition parameters (kVp and mAs, reconstruction algorithm, dose reduction software). Combinations of kVps that range from 80-140 kVp, and tube current time product from 14-125 mAs were individually scored by using a Likert scale from 1-5 in 4 separate anatomical areas (skull base, thoracic spine, pelvis, and distal femora). Correlation between readers scores and effective doses were obtained by using correlation coefficient statistical analysis, statistical significance was considered P < .01. Interobserver agreement was assessed by using a Bland and Altman plot. Interobserver agreement in each of the 4 anatomical areas was assessed by using kappa statistics. A single set of parameters was then selected for use in future clinical trials in a cohort of patients referred for investigation of monoclonal gammopathy, including multiple myeloma.
Several sets of exposure parameters allowed low-dose whole-body CT to be performed with effective doses similar to skeletal survey while preserving diagnostic image quality. Individual reader's and average combined scores showed a strong inverse correlation with effective dose (reader 1, r = -0.78, P = .0001; reader 2, r = -0.75, P = .0003); average combined scores r = -0.81, P < .0001). Bland and Altman plot of overall scores shows reasonable interobserver agreement, with a mean difference of 1.055.
Whole-body low-dose CT can be used to obtain adequate CT image quality to assess normal osseous detail while delivering effective doses similar to those associated with conventional radiographic skeletal survey.
研究剂量参数对全身低剂量多层螺旋 CT（CT）图像质量的影响，试图得出在因浆细胞疾病而接受检查的患者中，既能获得可诊断质量的骨骼系统图像，又不使辐射剂量明显增加的参数。
使用一具尸体，由 2 名放射科医生分别评估 14 种不同的全身低剂量 CT 方案，这些医生对采集参数（kVp 和 mAs、重建算法、剂量降低软件）不知情。kVp 从 80-140 kVp 范围和管电流时间乘积从 14-125 mAs 范围分别进行评分，采用 4 个独立解剖区域（颅底、胸椎、骨盆和股骨远端）的 1-5 分李克特量表进行评分。通过相关系数统计分析获得读者评分与有效剂量之间的相关性，认为 P <.01 时具有统计学意义。通过 Bland 和 Altman 图评估观察者间的一致性。通过kappa 统计评估 4 个解剖区域的每个区域的观察者间一致性。然后为未来的临床试验选择一组参数，该组参数将用于因单克隆丙种球蛋白病（包括多发性骨髓瘤）而接受检查的患者队列中。
多组暴露参数允许在有效剂量与骨骼调查相似的情况下进行全身低剂量 CT，同时保留诊断图像质量。单个读者评分和平均组合评分与有效剂量呈强烈的负相关（读者 1，r = -0.78，P =.0001；读者 2，r = -0.75，P =.0003）；平均组合评分 r = -0.81，P <.0001）。总体评分的 Bland 和 Altman 图显示出合理的观察者间一致性，平均差异为 1.055。
全身低剂量 CT 可用于获得足够的 CT 图像质量，以评估正常的骨骼细节，同时提供与常规放射性骨骼调查相关的有效剂量。
