Abstract: BACKGROUND: For the imaging of ossicular chains, muscles, bony labyrinths, ligaments and other structures, conventional thin-slice CT scans are difficult to achieve the most ideal results.
OBJECTIVE: To evaluate the image quality and radiation dose of High Resolution (HR) precise tomographic reconstruction algorithm in thin-layer CT scan of the middle and inner ears.
METHODS: Thin-layer scanning of the inner ear was performed in 21 volunteers. All scanned images were reconstructed by two reconstruction algorithms. The study group was reconstructed by 0.275 mm HR precision tomography, and the control group was reconstructed by 0.55 mm conventional thin layer. The images were processed by multiplanar reconstruction technology, and the display rates of anterior malleolar ligament, posterior anvil ligament, superior malleolar ligament and lateral malleolar ligament were calculated, and the image display effects of ossicular chain, muscle, labyrinthine and ligament were scored subjectively. The volume CT dose index volume and dose length product were recorded, and the effective dose was calculated. The study protocol was implemented in line with the ethic requirements of the First Affiliated Hospital of Jinzhou Medical University, and all the subjects were fully informed of the study procedures.
RESULTS AND CONCLUSION: All anatomical structures could be seen in axial and coronal images of HR precision tomography reconstruction and conventional thin-layer reconstruction (P > 0.05). In axial and coronal images, the display quality of the middle and inner ear structure in the study group was significantly better than that in the control group (P < 0.05). The effective dose of precision tomography in middle and inner ear was (1.19±0.26) mGy. To conclude, precision tomography has higher image resolution, by which we can observe the structures of the middle and inner ears more clearly.

Key words: CT, precision tomography, scanning, middle ear imaging, inner ear imaging, reconstruction algorithm, imaging