State-of-the-Art computed tomography of primate skulls--comparison of different scan-protocols

To evaluate the image quality of different scan-protocols on 3 different CT-scanners for data acquisition of skulls of apes and monkeys with special respect on imaging the paranasal sinuses, we compared CT image quality in 452 skulls on either the Philips "Mx8000" Multi-Slice CT, the "Aura" Spiral CT or the "T omoscanM" CT scanner. Therefore, we used sequential and volume scanning as well as different slice thickness, table feed, voltage and X-ray current intensity. Representative axial scans of the anonymized studies as well as three-dimensional reconstructions were independently analyzed by an experienced radiologist and an anthropologist, using a study protocol covering relevant anatomical findings. Low-Dose protocols at 40 mAs demonstrated an equal diagnostic value with better CT-performance due to lower overheatening of the X-ray tube in all studies. Resolution, especially in small anatomical structures, was best with multi-slice CT. On both single-slice scanners resolution was significantly better with sequential-protocols (slice 2-5 mm; feed 1:1) than with volume-protocols. Volume scans are required for 3D-reconstruction. Best 3D results were achieved with "M x8000" due to its better spatial resolution, followed by the "Aura" scanner. Multi-slice CT (MSCT) was found to be the superior method for the radiographic evaluation of small anatomical structures. However, there is no significant loss of information with thin sequential scans in LD technique on a single-slice spiral CT scanner. Volume-data aquisition is required for 3D reconstruction.