A head motion estimation algorithm for motion artifact correction in dental CT imaging

作者：Hernandez Daniel; Eldib Mohamed Elsayed; Hegazy Mohamed A A; Cho Myung Hye; Cho Min Hyoung; Lee Soo Yeol^*

来源：Physics in Medicine and Biology, 2018, 63(6): 065014.

DOI：10.1088/1361-6560/aab17e

• motion correction
• motion estimation
• CBCT
• dental CT

A small head motion of the patient can compromise the image quality in a dental CT, in which a slow cone-beam scan is adopted. We introduce a retrospective head motion estimation method by which we can estimate the motion waveform from the projection images without employing any external motion monitoring devices. We compute the cross-correlation between every two successive projection images, which results in a sinusoid-like displacement curve over the projection view when there is no patient motion. However, the displacement curve deviates from the sinusoid-like form when patient motion occurs. We develop a method to estimate the motion waveform with a single parameter derived from the displacement curve with aid of image entropy minimization. To verify the motion estimation method, we use a lab-built micro-CT that can emulate major head motions during dental CT scans, such as tilting and nodding, in a controlled way. We find that the estimated motion waveform conforms well to the actual motion waveform. To further verify the motion estimation method, we correct the motion artifacts with the estimated motion waveform. After motion artifact correction, the corrected images look almost identical to the reference images, with structural similarity index values greater than 0.81 in the phantom and rat imaging studies.

• 出版日期2018-3