Noise properties for three weighted Feldkamp algorithms using a 256-detecotor row CT-scanner: case study for hepatic volumetric cine imaging.
In cone-beam geometry, image quality may be degraded or artifacts may occur if the cone angle is substantially wide. This is because a cone-beam scan along a circular orbit does not collect the complete set of data required to make an exact reconstruction of all volumetric data. To increase temporal resolution and thus image quality in cone-beam geometry, Silver proposed the new half-scan algorithm (NHS-FDK), which extends Parker's weighting function (HS-FDK) by utilizing a larger range up to 2pi. Here, we evaluated these algorithms for hepatic contrast-enhanced CT in cine scan mode using a 256-detector row CT. The full-scan (FS-FDK) images show uniform distribution of the image noise and CT-number uniformity. Image noise and CT-number uniformity with HS-FDK and NHS-FDK images follow the initial projection angle. HS-FDK images therefore have more changeable higher intensity (brighter) and a lower intensity (darker) areas than respective FS-FDK and NHS-FDK images. We concluded that, considering the trade-off between image quality and temporal resolution, the NHS-FDK algorithm is useful in volumetric cine imaging for the abdomen.
Department of Medical Physics, National Institute of Radiological Sciences, Chiba 263-8555, Japan. shinshin@nirs.go.jp
Shinichiro
S
Mori
Masahiro
M
Endo
Takayuki
T
Obata
Riwa
R
Kishimoto
Hirotoshi
H
Kato
Susumu
S
Kandatsu
Hirohiko
H
Tsujii
Shuji
S
Tanada
D000368:Aged; D000465:Algorithms; D016477:Artifacts; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000008:administration & dosage; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000145:classification* / Q000295:instrumentation / Q000379:methods*
D003287:Contrast Media