Logistic advantages of four-section helical CT in the abdomen and pelvis

Multisection helical computed tomography (CT) has the potential for providing data sets with better section profiles, more anatomic coverage, and shorter breath-holding periods. Our purpose was to quantitate these advantages in a clinical setting when imaging the abdomen and pelvis.

CT parameters including collimation, timing, z-axis coverage, and milliamperes were gathered retrospectively for the image set of both single-section (GE CT/i with 0.8-s rotation) and four-section (GE QX/i Lightspeed with 0.8-s rotation) helical CT scanners. Data were recorded for the abdomen and pelvis CT (n = 30 each), dual-phase liver CT including the pelvis (n = 15 each), and dual-phase pancreas CT (n = 15 each).

The abdominal and pelvic CT averaged 128.4 +/- 5.4 s for single-section scanners (70-s delay, two breath-holds of 21.1 and 17. 7 s with a 19.5-s interscan delay) and 92.2 +/- 2.2 s for the four-section scanner (70-s delay and a 22.2-s breath-hold; p < 0. 0001). For the dual liver and pelvis CT, single-section scanners averaged 119.9 +/- 7.5 s (30-s delay, 15.8-s arterial phase, 20.0-s interscan delay, 21.2-s venous phase, 19.5-s interscan delay, and 14. 2 s for the remaining abdomen and pelvis), whereas the four-section scanner averaged 86.8 +/- 2.5 s (30-s delay, 6.7-s arterial phase, 27.9-s interscan delay, and 21.8-s venous phase including the pelvis; p < 0.0001). For the dual pancreas CT, single-section scanners averaged 86.7 +/- 2.5 s (20-s delay, 28.3-s arterial phase, 17.8-s interscan delay, 21.7-s venous phase), whereas the four-section scanner averaged 78.0 +/- 2.9 s (20-s delay, 9.7-s arterial phase, 30.7-s interscan delay, 13.0-s venous phase; p < 0. 0001).

CT scanners having four-section technology can reduce overall data acquisition times by 10-30% and total milliamperes by 50-60% depending on the protocol with thinner slice profiles.