Zeman R K, Silverman P M, Berman P M, Weltman D I, Davros W J, Gomes M N
Department of Radiology, Georgetown University Medical Center, Washington, DC 20007.
Radiology. 1994 Nov;193(2):555-60. doi: 10.1148/radiology.193.2.7972779.
To determine the value of variable collimation and overlapping reconstruction in helical computed tomography (CT) to evaluate abdominal aortic aneurysm.
Twenty-three patients (15 men and eight women, aged 59-85 years) underwent helical CT scanning, nine with fixed 5-mm collimation and 14 with 3- and 7-mm collimation combined. The ability to visualize main and accessory renal arteries, detect stenoses, and determine aneurysm extent were evaluated.
Extent of aneurysm was accurately determined in 17 of 23 cases without overlapping sections; failure to detect ancillary findings such as accessory arteries or stenosis occurred in nine of these cases. With overlapping sections, determination of aneurysm extent improved to 19 of 23 cases and ancillary errors were reduced to four. Five errors occurred with fixed collimation and three errors with variable collimation.
Overlapping, variable-collimation helical CT allows for a more complete evaluation of abdominal aortic aneurysms than does nonoverlapping, fixed-collimation CT.
确定螺旋计算机断层扫描（CT）中可变准直和重叠重建在评估腹主动脉瘤方面的价值。
23例患者（15名男性和8名女性，年龄59 - 85岁）接受了螺旋CT扫描，其中9例采用固定5毫米准直，14例采用3毫米和7毫米准直相结合。评估了观察肾主、副动脉的能力、检测狭窄的能力以及确定动脉瘤范围的能力。
23例中有17例在无重叠层面时准确确定了动脉瘤范围；其中9例未能检测到诸如副动脉或狭窄等辅助发现。采用重叠层面后，23例中有19例动脉瘤范围的确定得到改善，辅助错误减少至4例。固定准直出现5例错误，可变准直出现3例错误。
与非重叠、固定准直的CT相比，重叠、可变准直的螺旋CT能够更全面地评估腹主动脉瘤。
