Fundamentals of Multichannel CT

Multichannel computed tomography (MCCT) has created a technical revolution in CT scanning. Following the introduction of single-channel helical scanning in 1989, 4-channel systems were introduced in 1998 and 16-channel systems in 2002. The core of this new technique is the X-ray detector array design, which allows for multiple simultaneous registration of slice information during gantry rotation. This design allows for faster scanning and acquisition of thinner slice widths. The high-speed scanning also minimizes motion artifacts. The ability to scan with very thin slice thickness creates a scanned volume with isotropic voxels. This allows for two- and three-dimensional reconstructions with similar resolution as the source images. MCCT also allows for higher X-ray tube currents, which create better penetration of metallic orthopedic fixation devices. Musculoskeletal imaging benefits from MCCT because large anatomic areas may be covered with thin slices. When needed, high tube currents can be applied for scanning areas of interest in the presence of metal. Thin slice acquisition allows isotropic viewing, which we use routinely.

KEYWORDS

Multichannel computed tomography - multislice computed tomography - isotropic imaging

REFERENCES

• 1 Berland L L, Smith J K. Multidetector-array CT: once again, technology creates new opportunities.  Radiology. 1998;  209 327-329
• 2 Mahesh M. Search for isotropic resolution in CT from conventional through multiple-row detector.  Radiographics. 2002;  2 949-962
• 3 Liang Y, Kruger R A. Dual-slice spiral versus single-slice spiral scanning: comparison of the physical performance of two computed tomography scanners.  Med Phys. 1996;  23 205-220
• 4 Silverman P M, Kalender W A, Hazle J D. Common terminology for single and multislice helical CT.  AJR. 2001;  176 1135-1136
• 5 Hu H. Multi-slice spiral CT: scan and reconstruction.  Med Phys. 1999;  26 5-18
• 6 Schaller S, Flohr T, Klingenbeck K, Krause J, Fuchs T, Kalender W A. Spiral interpolation algorithm for multislice spiral CT. I. Theory.  IEEE Trans Med Imaging. 2000;  19 822-834
• 7 McCollough C H, Zink F E. Performance evaluation of a multi-slice CT system.  Med Phys. 1999;  26 2223-2230
• 8 Mahesh M, Scatarige J C, Cooper J, Fishman E K. Dose and pitch relationship for a particular multislice CT scanner.  AJR. 2001;  177 1273-1275
• 9 Kalender W A, Seissler W, Klotz E, Vock P. Spiral volumetric CT with single-breath-hold technique, continuous transport, and continuous scanner rotation.  Radiology. 1990;  176 181-183
• 10 Gies M, Kalender W A, Wolf H, Suess C. Dose reduction in CT by anatomically adapted tube current modulation. I. Simulation studies.  Med Phys. 1999;  26 2235-2247