Cardiac spiral dual-source CT with high pitch: a feasibility study.
Increase of pitch in spiral CT decreases data acquisition time; dual-source CT (DSCT) systems provide improved temporal resolution. We evaluated the combination of these two features. Measurements were performed using a commercial DSCT system equipped with prototype software allowing pitch factors from p = 0.35 to 3.0. We measured slice sensitivity profiles as a function of pitch to assess spatial resolution in the z-direction and the contrast of structures moved periodically to measure temporal resolution. Additionally we derived modulation transfer functions to provide objective parameters; both spatial and temporal resolution were essentially unchanged even at high pitch. CT of the cardiac region of three pigs was performed at p = 3.0. In vivo CT images confirmed good image quality; direct comparison with standard low-pitch phase-correlated CT image datasets showed no significant difference. For a normalized z-axis acquisition of 12 cm, the corresponding effective dose value was 2.0 mSv for the high-pitch CT protocol. We conclude that spiral DSCT imaging with a pitch of 3.0 can provide unimpaired image quality with respect to spatial and temporal resolution. Applications to cardiac and thoracic imaging with effective dose below 1 mSv are possible.
Ertel
Dirk
D
Institute of Medical Physics (IMP), University of Erlangen-Nürnberg, Henkestrasse 91, 91052, Erlangen, Germany.
Lell
Michael M
MM
Harig
Frank
F
Flohr
Thomas
T
Schmidt
Bernhard
B
Kalender
Willi A
WA
D000818:Animals; D005240:Feasibility Studies; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D019047:Phantoms, Imaging; D011856:Radiographic Image Enhancement / Q000379:methods*; D013902:Radiography, Thoracic / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D036542:Tomography, Spiral Computed / Q000295:instrumentation / Q000379:methods*