Program Information
A Novel Dynamic Profile-Driven 4D-MRI Reconstruction Method
D Lee1*, S Kim1 , J Palta1 , P Keall2 , T Kim1 , (1) Virginia Commonwealth University, Richmond, VA, (2) University of Sydney, Camperdown, NSW
Presentations
TU-D-601-1 (Tuesday, August 1, 2017) 11:00 AM - 12:15 PM Room: 601
Purpose: Compared to MRI, the internal target volume (i.e. encompassed tumor motion and volume) is smaller in 4D-CT due to compromised (or averaged) axial images at the end of inhalation and exhalation). While retrospective (image sorting and binning) and prospective (triggered k-space sampling) 4D-MRI approaches are improved, both approaches still suffer from breathing variation. In this work, we present a dynamic profile-driven 4D-MRI reconstruction method to improve the quality of 4D-MRI whilst maintaining an absolute organ position in the presence of respiratory motion for real-time thoracic image-guided radiotherapy.
Methods: This new 4D-MRI reconstruction method is called Dynamic Profile-Driven (DPD), and utilizes 2D dynamic profile images (i.e. orthogonal images of 4D image datasets) to match the same (or similar) respiratory state in conjunction with 4D-MRI datasets (2D cine images on multiple pre-determined coronal planes over a volume of interest). Internal diaphragm information is utilized to sort, match and combine the two orthogonal dynamic profile images and 4D-MRI images with respect to diaphragm position and shape, thereby providing 4D-MRI with minimal respiratory-related artifacts. In this study, the DPD method was compared to 2D dynamic profile images (reference) for forty four coronal 4D-MRI datasets acquired from 13 healthy human subjects.
Results: In the difference (root mean square error) of diaphragm positions between the reference and the corresponding 4D-MRI, the DPD method maintained the diaphragm position within 4.1 mm (range 0.4 mm to 16.2 mm) in irregular breathing (i.e. free-breathing), whilst it was 2.9 mm (range 0.2 mm to 11.1 mm) in regular breathing (i.e. respiratory guidance).
Conclusion: The novel Dynamic Profile-Driven reconstruction method successfully reconstructed 4D-MRI without external surrogates. The image quality and the accuracy of spatial information were maintained for both irregular and regular breathing patterns. The DPD method can be used for image guidance for thoracic and abdominal cancer radiotherapy.
Contact Email: