[Factors of image quality in spiral x-ray computed tomography].
In helical CT, there are 4 mains factors of quality: The in-plane spatial resolution that is the same in conventional CT; The spatial resolution on the Z axis, which is the slice thickness. The increase factor of the slice thickness between a conventional and a helical CT depends on the pitch and the reconstruction algorithm. The value of the increase factor can be easily calculated; The signal to noise ratio which depends on the collimation, the mA, the KV and the reconstruction algorithm. The signal to noise ratio is not depending on the table speed; The reconstruction interval which can be less than the slice thickness. Then the contrast of small lesion is improved and stair-step artifacts are reduced in 3D reformations.
Ernst
O
O
Radiologie Est, CHU Lille.
Gaillandre
L
L
Mizrahi
D
D
Sergent
G
G
Bonvarlet
P
P
L'Herminé
C
C
D000465:Algorithms; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D011786:Quality Control; D011856:Radiographic Image Enhancement; D014057:Tomography, X-Ray Computed / Q000379:methods*
Facteurs de qualité de l'image en scanner spiralé.