Yasuo Nakae

Clinical evaluation of a newly developed method for avoiding artifacts caused by dental fillings on X-ray CT.

To evaluate the clinical usefulness of gantry tilt scanning as an image reconstruction technique for avoiding artifacts caused by metallic dental fillings. Gantry tilt scanning was used with multidetector-row computed tomography for imaging in patients with dental fillings. Using a novel PC-based program, the oblique images obtained were reconstructed to transverse images using nearest neighbor and bilinear interpolation methodologies in order to avoid metallic streak artifacts. Coronal images were reformatted with the reconstructed transverse images, and the continuity of the reconstructed images was evaluated. Gantry tilt scanning was performed in 12 patients with metal artifacts, and the original and reconstructed images were classified into four grades and assessed by two radiologists. Results of the clinical evaluation indicated that the original images with artifacts, only 4% had good image quality in the region around the medial pterygoid muscle, only 8% depicted areas around the internal carotid artery and internal jugular vein, and only 12% could depict the areas around the parotid gland in the clinical evaluation. These values were improved to 60, 96, and 100%, respectively, in the reconstructed transverse images. Gantry tilt scanning as an image reconstruction technique improves image quality and removes most, if not all, artifacts caused by metallic dental fillings. The resulting images can be used in the evaluation of oropharyngeal lesions in patients with dental fillings.