Contrast resolution in multidetector-row CT with 16 detector rows: phantom study.
This study was performed for evaluation of high- and low-contrast resolution in multidetector-row CT (MDCT) with 16 detector rows. For evaluating high-contrast resolution, a phantom was scanned ten times at 100 mA s with 24 patterns of scan parameters under several X-ray beam widths, X-ray tube voltages, X-ray tube rotation times, and helical pitches. Three radiological technologists observed the images visually. For evaluating low-contrast resolution, a phantom was scanned ten times at 100 mA s with the 24 patterns of scan parameters, which were the same as for high-contrast resolution. The images were examined based on receiver operating characteristic (ROC) curves. The high-contrast resolution deteriorated in the off-center locations when helical pitches of 1.375:1 or 1.75:1 were used. High helical pitch (>0.9375:1) and low tube voltage had significant effects on the low-contrast resolution. However, a wide X-ray beam width and short X-ray tube rotation time had no definite influence. Therefore, a helical pitch of 0.5625:1 should be used when the contrast resolutions are really important, and a wide X-ray beam width and short X-ray tube rotation time can improve the temporal resolution without deterioration of contrast resolution.
Matsubara
Kosuke
K
Department of Radiological Technology, Kanazawa University Hospital, Kanazawa, Ishikawa, Japan. matsuk@rad.m.kanazawa-u.ac.jp
Koshida
Kichiro
K
Suzuki
Masayuki
M
Hayashi
Norio
N
Takata
Tadanori
T
Tsujii
Hideo
H
Yamamoto
Tomoyuki
T
Matsui
Osamu
O
D019047:Phantoms, Imaging; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods
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