Electronic noise in CT detectors: Impact on image noise and artifacts.
OBJECTIVE
The objective of our study was to evaluate in phantoms the differences in CT image noise and artifact level between two types of commercial CT detectors: one with distributed electronics (conventional) and one with integrated electronics intended to decrease system electronic noise.


METHODS
Cylindric water phantoms of 20, 30, and 40 cm in diameter were scanned using two CT scanners, one equipped with integrated detector electronics and one with distributed detector electronics. All other scanning parameters were identical. Scans were acquired at four tube potentials and 10 tube currents. Semianthropomorphic phantoms were scanned to mimic the shoulder and abdominal regions. Images of two patients were also selected to show the clinical values of the integrated detector.


RESULTS
Reduction of image noise with the integrated detector depended on phantom size, tube potential, and tube current. Scans that had low detected signal had the greatest reductions in noise, up to 40% for a 30-cm phantom scanned using 80 kV. This noise reduction translated into up to 50% in dose reduction to achieve equivalent image noise. Streak artifacts through regions of high attenuation were reduced by up to 45% on scans obtained using the integrated detector. Patient images also showed superior image quality for the integrated detector.


CONCLUSIONS
For the same applied radiation level, the use of integrated electronics in a CT detector showed a substantially reduced level of electronic noise, resulting in reductions in image noise and artifacts, compared with detectors having distributed electronics.
1 Department of Radiology, Mayo Clinic, CT Clinical Innovation Center, 200 First St SW, East 2 Mayo Bldg, Rochester, MN 55905.
Xinhui
X
Duan
Jia
J
Wang
Shuai
S
Leng
Bernhard
B
Schmidt
Thomas
T
Allmendinger
Katharine
K
Grant
Thomas
T
Flohr
Cynthia H
CH
McCollough
D016477:Artifacts; D004581:Electronics / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018511:Systems Integration; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*; D014159:Transducers