Dalal Tejas, Kalra Mannudeep K, Rizzo Stefania M R, Schmidt Bernhard, Suess Christoph, Flohr Thomas, Blake Michael A, Saini Sanjay
Division of Abdominal Imaging and Intervention, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, White 270-E, Boston, MA 02114, USA.
Radiology. 2005 Aug;236(2):671-5. doi: 10.1148/radiol.2362041565.
The institutional review board approved this Health Insurance Portability and Accountability Act-compliant study protocol, with waiver of informed consent. The purpose of the study was to retrospectively evaluate the combined automatic tube current modulation technique in patients with orthopedic metallic prostheses. Five hundred abdominal-pelvic computed tomographic (CT) studies performed with combined modulation technique were reviewed to identify nine patients with metallic prostheses (mean age, 66 years; range, 35-86 years; male-female ratio, 5:4). On the basis of age and transverse abdominal images, these patients were matched with nine others with no metallic prostheses (mean age, 56 years; range, 36-72 years; male-female ratio, 4:5) who were control patients. Images were graded for extent and severity of streak artifacts (grade 1, streak artifact present but not substantially compromising evaluation of adjacent structures; grade 2, streak artifact present and slightly compromising evaluation of adjacent structures; and grade 3, streak artifact present and severely compromising evaluation of adjacent structures). Student t test was performed for statistical analysis. There was no difference in mean effective tube current-time product between study and control patients (P > .49). With automatic tube current modulation, an increase in CT dose caused by metallic prostheses can be successfully avoided.
机构审查委员会批准了这项符合《健康保险流通与责任法案》的研究方案，并豁免了知情同意。本研究的目的是回顾性评估联合自动管电流调制技术在患有骨科金属假体的患者中的应用。回顾了500例采用联合调制技术进行的腹部-盆腔计算机断层扫描（CT）研究，以确定9例有金属假体的患者（平均年龄66岁；范围35 - 86岁；男女比例为5:4）。根据年龄和腹部横断面图像，将这些患者与另外9例无金属假体的对照患者（平均年龄56岁；范围36 - 72岁；男女比例为4:5）进行匹配。对图像的条纹伪影程度和严重程度进行分级（1级，存在条纹伪影但未严重影响对相邻结构的评估；2级，存在条纹伪影且轻微影响对相邻结构的评估；3级，存在条纹伪影且严重影响对相邻结构的评估）。采用学生t检验进行统计分析。研究组和对照组患者的平均有效管电流-时间乘积无差异（P > 0.49）。通过自动管电流调制，可以成功避免金属假体导致的CT剂量增加。
