Mohamed S. Hefny

Learn More
Statistical shape models using a principal-component analysis are inadequate for studying shapes that are in non-linear manifolds. Principal tangent components use a matrix Lie group that maps a non-linear manifold to a corresponding linear tangent space. Computations that are performed on the tangent space of the manifold use linear statistics to analyze(More)
Hip resurfacing is a surgical option for osteoarthritis young and active patients. Early failures has been reported due to improper implant placement. Computer-assisted surgery is a promising avenue for more successful procedures. This paper presents a novel automatic surgical planning for computer-assisted hip resurfacing procedures. The plan defined the(More)
BACKGROUND One of the challenges in natural orifice transluminal endoscopic surgery (NOTES) is spatial orientation. The Queen's NOTES group has devised a novel method of orientation by using a magnetic device that passes within an endoscope channel allowing for 3-dimensional imaging of the shape and orientation of the endoscope. OBJECTIVE To assess the(More)
We present a quantitative model to analyze the detrimental effects of for edema on the quality of prostate brachytherapy implants We account for both tissue expansion and implant migration by mapping intra-operative ultrasound and post-implant CT. We pre-process the ultrasound with a phase congruency filter, and map it to the volume CT using a B-spline(More)
Conventional computer-assisted orthopaedic surgery (CAOS) involves many time-consuming and patient-dependent repeatable tasks in which automation is highly desirable. Relevant work includes the development of efficient and accurate automatic solutions for CAOS tasks such as region-of-interest segmentation (Chu 2014), implant fitting (Wu 2015), and surgical(More)
One marker for early-onset hip arthritis is femoral acetabular impingement. The current standard way of quantifying impingement is manual calculation of anatomical measures on plain radiographs, including the α-angle. Such measurements are user-dependent and prone to error. We provided a robust computational alternative and proposed using numerical fitting(More)
Manifold statistical shape analysis of the distal radius M. S. Hefny, D. R. Pichora, J. F. Rudan, R. E. Ellis 1 Queen’s University, School of Computing, Kingston, Canada 2 Queen’s University, Department of Mechanical and Material Engineering, Kingston, Canada 3 Queen’s University, Department of Surgery, Kingston, Canada 4 Queen’s University, Department of(More)
  • 1