|
|
|
| Effect of different scan field of view on CT value and water(iodine) concentration from#br# standard phantom in single-source dual-energy CT |
| Department of Radiology, Dalian Medical University 1st Affiliated Hospital, Dalian Liaoning 116011, China |
|
|
|
|
Abstract Objective: To investigate the effect of different scan field of views(FOVs) on CT value, water-iodine concentration and SD value of standard water phantom by single-source dual-energy CT. Methods: A standard water phantom(GE, USA) was scanned by a single-source dual-energy CT scanner(GE Discovery 750HD, USA) with large and medium FOV, respectively(group L: large FOV; group M: medium FOV)． The other parameters were as follows: tube voltage switched instantaneously between 140 kVp and 80 kVp. Current modulation changed from 165 to 262.5 mAs. Thickness was 5 mm and pitch was 1.375. Each protocol collected 6 images and reconstructed into images with 1.25 mm-thickness. Circular ROI with area of around 3 000 mm2 was put in the middle, front, back, left and right of the water phantom, respectively on AW4.5 workstation. CT value and SD value of two groups were measured on the 70 keV monochromatic image. And water-iodine concentration and SD value were measured on the water-iodine concentration image. Independent-samples t test was used for statistical analysis. Results: There were statistical differences of CT value and SD value between group M and L(P＜0.05)． CT value of group M((3.07±1.49) HU) was less than that of group L((2.11±2.47) HU), closer to the gold standard. SD value of group M was bigger than group L. There was a significant difference of water-iodine concentration between group M and L(P＜0.05)． The SD value of water-iodine concentration was significantly lower than that of CT value between group M and L(P<0.001). Conclusion: The CT value and water-iodine concentration can be affected by scanning field of view. And medium scanning field is better than large scanning field. Compared with conventional CT, the change of scanning field has less effect on spectral CT which can be more accurate for quantitative analysis.
|
|
Received: 28 September 2015
|
|
|
|
Corresponding Authors:
LIU Yi-jun
|
|
|
|
[1]王乐，刘斌，余永强，等. 能谱成像测量单能量下CT值与碘含量的相关性分析[J]. 实用放射学杂志，2012，28（5）：784-787.
[2]Matsumoto K, Jinzak M, Tanami Y, et al． Virtual monochro-matic spectral imaging with fast kilovoltage switching: improved image quality as compared with that obtained with conventional 120-kVp CT[J]． Radiology, 2011, 259(1): 257-262．
[3]兰永树，黄文龙，朱德强，等. 影响CT值测量的因素及对策的探讨[J]. 实用放射学杂志，2006，22（3）：352-355.
[4]叶伦，叶亦兰，冉艮龙，等. 宝石能谱CT成像原理及临床应用[J]. 中华临床医师杂志：电子版，2013，7（19）：8919-8921.
[5]Rosenkrantz BA, Mendiratta-Lala M, Bartholmai JB, et al. Clinical utility of quantitative imaging[J]. Ann R Coll Surg Engl Acad Radiol, 2015, 22(1): 33-49.
[6]赵永为，郭小超，王霄英，等. 扫描视野对双能CT成像CT值及物质分离的影响—模体研究[J]. 放射学实践杂志，2012，27（3）：271-273. |
|
|
|
