Flat-panel CT versus 128-slice CT in temporal bone imaging : assessment of image quality and radiation dose

Objective: We compared the image quality and radiation dose of flat-panel CT (FPCT) and multi-slice CT (MSCT) performed respectively with an angiographic unit and a 128-slice CT scanner. We investigated whether the higher spatial resolution of FPCT translated into higher image quality and we sought to eliminate inter-subject variability by scanning temporal bone specimens with both techniques. Materials and methods: Fifteen temporal bone specimens were imaged with FPCT and MSCT. Two neuroradiologists experienced in otoradiology evaluated 30 anatomical structures with a 0–2 score; 18 structures important from a clinical perspective were assigned a twofold value in calculation of the overall score. The radiation dose was calculated through the use of an anthropomorphic phantom. Results: The image quality was significantly higher for FPCT than MSCT for 10 of the 30 anatomical structures; the overall score was also significantly higher for FPCT (p = 0.001). The equivalent dose of the two techniques was very similar, but with different effective doses to the organs. Conclusion: FPCT performed on an angiographic unit provides higher image quality in temporal bone assessment compared to MSCT performed on a 128-slice CT scanner thanks to its higher spatial resolution, with comparable equivalent doses but different effective doses to the organs.