2020-772 METHOD FOR SIMULTANEOUSLY REGISTERING MULTIPLE LUNG CT SCANS: OBJECTIVE FUNCTION

SUMMARY

UCLA researchers in the Department of Radiation Oncology have developed a novel approach to generate image-based analysis of lungs and breathing for lung CT (computed tomography) scans. This method can perform simultaneous registration and ventilation measurement using free-breathing CT scans, and could potentially revolutionize pulmonary, surgery, and radiology.

BACKGROUND

Human lungs have two primary purposes, transporting air and gas exchange. Lung function is fundamentally connected with its motion and distortion, rendering CT the only useful 3D high resolution lung imaging modality. CT image registration is critical to the quantitative understating and characterization of lung motion, breathing dynamics, biomechanical properties, and other structural and functional properties. However, the dynamic nature of breathing makes imaging of lungs challenging and attenuates the critical resolution needed for disease diagnosis. Deconvolution of breathing and lung activity, such as CT free-breathing quantitative tests could open the opportunity to develop a broad array of high resolution image-based techniques.

INNOVATION

Dr. Daniel Low and colleagues in the Department of Radiation Oncology at UCLA have developed a novel method for simultaneously registering a plurality of CT images of a region of interest, including a person’s lungs. The images may be acquired during free breathing, coached breathing, breath hold, or other circumstances such that the distortion of the lungs between images is minimized. One challenge of comparing multiple lung CT images is that the image intensities vary due to lung expansion. The inventors have derived a new equation by approximating the local change in lung expansion based on breathing and compensating for that change when comparing images. By applying this equation into CT image registration, the new approach allows multiple CT datasets acquisition over a single session, makes free-breathing CT scans possible.

APPLICATIONS

• Lung CT scan
• Radiation therapy
• Pulmonary disease

ADVANTAGES

• High resolution CT imaging
• Single session acquisition of multiple CT data sets
• Cost and time-effecting lung disease diagnosis
• Free-breathing CT scans

STATE OF DEVELOPMENT

This new approach was implemented in subregions of a research patient’s lungs. The patient had been sequentially scanned 25 times with a CT scanner while monitoring their breathing. Data shows an example of 2x2x2 cm3 regions after registration, showing that the process worked very well.

RELATED PAPERS

1. Gorbunova et al., Mass preserving image registration for lung CT, Medical Image Analysis (2012)
2. Low et al., A novel CT acquisition and analysis technique for breathing motion modeling, Phys. Med. and Biol. 58, L31-L36 (2013)
3. O’Connell et al., A prospective gating method to acquire a diverse set of free breathing CT images for model-based 4DCT, Phys. Med. Biol. 63, 10 pages (2018)