Budoff Matthew J, Kessler Paul, Gao Yan L, Qunibi Wajeh, Moustafa Moustafa, Mao Song S
Los Angeles Biomedical Research Institute at Harbor UCLA, Torrance, CA 90502, USA.
Acad Radiol. 2008 Jan;15(1):58-61. doi: 10.1016/j.acra.2007.08.011.
In the Calcium Acetate Renagel Evaluation (CARE)-2 study, the effects of calcium acetate plus atorvastatin (Lipitor) on the progression of coronary artery calcifications (CACs) are evaluated versus those of Renagel, monitored using dual electron beam tomography (EBT) scans (two scans at study initiation and two at follow up). The aim of this study is to estimate the interscan variation for the Agatston score and for the volume score determined in patients with end-stage renal disease (ESRD) in the CARE-2 study.
CAC score and volume were measured at study initiation in 463 ESRD subjects (mean age: 59.4 +/- 12.5 years, 48.3% female). All patients underwent dual scanning using an EBT, as first scan of two needed to measure the progression of CAC when treated with sevelamer (Renagel) compared with calcium acetate with or without atorvastatin. All scans in all participants were completed by using an EBT system (GE Imatron, South San Francisco, CA). Interscan variability was defined by the following formula: abs (scan A - scan B) / (0.5 x scan A + 0.5 x scan B) x 100%, where A and B denote the first and second scan, respectively, of the dual scan procedure performed before treatment. We evaluated the reproducibility of the cutpoints commonly used for calcium scores clinically, namely 1-30, 31-100, 101-400, and >400.
The CAC interscan variability was 11.8% using the Agatston score and 10.3% using the volume score. The reproducibility was then assessed using cutpoints 1-30, 31-100, 101-400, and >400. Agatston score variability for the four subgroups was 61.3%, 23%, 16.1%, and 8.2%, respectively (mean variability, 11.8%). Volume score variability was 60.0%, 14.4%, 14.6%, and 7.7%, respectively (mean variability, 10.3%). The correlation coefficient for scan A to scan B goes up significantly with increasing calcium scores and reaches 0.99 for scores greater than 400 (P < .0001).
Interscan variability was sufficiently small for patients with calcium scores greater than 30. Our study thus demonstrates a sufficient reproducibility of the calcium score using EBT. This score allows for accurate serial assessment of these patients and for comparing different therapies.
在醋酸钙司维拉姆评估（CARE）-2研究中，对比了醋酸钙联合阿托伐他汀（立普妥）与司维拉姆对冠状动脉钙化（CAC）进展的影响，并使用双能电子束断层扫描（EBT）进行监测（研究开始时扫描两次，随访时扫描两次）。本研究的目的是评估CARE-2研究中终末期肾病（ESRD）患者阿加西积分和容积积分的扫描间变异。
在463例ESRD受试者（平均年龄：59.4±12.5岁，48.3%为女性）研究开始时测量CAC积分和容积。所有患者均使用EBT进行双次扫描，这是测量司维拉姆（Renagel）与含或不含阿托伐他汀的醋酸钙治疗时CAC进展所需的两次扫描中的第一次。所有参与者的所有扫描均使用EBT系统（GE Imatron，加利福尼亚州南旧金山）完成。扫描间变异由以下公式定义：|扫描A - 扫描B| / （0.5×扫描A + 0.5×扫描B）×100%，其中A和B分别表示治疗前进行的双次扫描中的第一次和第二次扫描。我们评估了临床上常用的钙积分切点（即1 - 30、31 - 100、101 - 400和>400）的可重复性。
使用阿加西积分时，CAC扫描间变异为11.8%，使用容积积分时为10.3%。然后使用切点1 - 30、31 - 100、101 - 400和>400评估可重复性。四个亚组的阿加西积分变异分别为61.3%、23%、16.1%和8.2%（平均变异为11.8%）。容积积分变异分别为60.0%、14.4%、14.6%和7.7%（平均变异为10.3%）。扫描A与扫描B的相关系数随钙积分增加而显著升高，钙积分大于400时达到0.99（P <.0001）。
对于钙积分大于30的患者，扫描间变异足够小。因此，我们的研究证明了使用EBT测量钙积分具有足够的可重复性。该积分可对这些患者进行准确的系列评估，并用于比较不同治疗方法。
