|
KMID : 0880420090100030260
|
|
Korean Journal of Radiology
2009 Volume.10 No. 3 p.260 ~ p.268
|
|
|
Optimization of the Scan Protocol for the Reduction of Diaphragmatic Motion Artifacts Depicted on CT Angiography: a Phantom Study Simulating Pediatric Patients with Free Breathing
|
|
Baek Jee-Hyun
Lee Whal
Chang Kee-Hyun
Chung Jin-Wook
Park Jae-Hyung
|
|
|
Abstract
|
|
|
Objective: This study was designed to optimize the scan protocol of CT angiography to reduce diaphragmatic motion artifacts in pediatric patients with free-breathing.
Materials and Method : A phantom with twelve tubes with different diameters was constructed. To simulate free-breathing, the phantom was connected to a motor, and the phantom moved along the axis of scan. Scans were performed under several conditions: different pitch (1, 1.5) and gantry rotation time (0.37 and 0.75 sec), and different movement range (1 cm, 3 cm) and rates (20/min, 40/min). For CT scanning, a 16-channel CT scanner was used and fixed factors of the CT protocol were as follows: 100 effective mAs, 80 kVp, reconstruction with a soft-algorithm, beam collimation 16 x 75 mm, reconstruction thickness of 1 mm, and an interval of 0.5 mm. CT scans were repeated five times. Each tube was evaluated with the use of a grading system (0 for images where tubes were not discriminable and 2 for images where tubes were clearly discriminable).
Results: A higher pitch and shorter gantry rotation time produced images with a higher grade. Average grades for the higher pitch (1.5) and faster gantry rotation time (0.37 sec) for each combination of movement were as follows: 1.94 (range 1 cm and rate 20/min), 1.42 (range 1 cm and rate 40/min), 0.86 (range 3 cm and rate 20/min) and 0.52 (range 3 cm and rate 40/min). Average grades for the lower pitch (1) and slower gantry rotation time (0.75 sec) for each combination of movement were 1.08, 0.56, 0.32 and 0.08, respectively.
Conclusion: The scanning speed and especially the pitch are important parameters for CT scans to overcome a respiratory motion artifact.
|
|
|
KEYWORD
|
|
|
Computed tomography, Infants and children, Cardiovascular system
|
|
|
FullTexts / Linksout information
|
|
 
|
|
|
Listed journal information
|
|
    
|
|