Engineering Commons^™

Shape Complexes: The Intersection Of Label Orderings And Star Convexity Constraints In Continuous Max-Flow Medical Image Segmentation., John S H Baxter, Jiro Inoue, Maria Drangova, Terry M Peters

Robarts Imaging Publications

Optimization-based segmentation approaches deriving from discrete graph-cuts and continuous max-flow have become increasingly nuanced, allowing for topological and geometric constraints on the resulting segmentation while retaining global optimality. However, these two considerations, topological and geometric, have yet to be combined in a unified manner. The concept of "shape complexes," which combine geodesic star convexity with extendable continuous max-flow solvers, is presented. These shape complexes allow more complicated shapes to be created through the use of multiple labels and super-labels, with geodesic star convexity governed by a topological ordering. These problems can be optimized using extendable continuous max-flow solvers. Previous approaches …

Diagnostic Quality Assessment Of Compressed Sensing Accelerated Magnetic Resonance Neuroimaging., Mohammad Kayvanrad, Amy Lin, Rohit Joshi, Jack Chiu, Terry Peters

Robarts Imaging Publications

PURPOSE: To determine the efficacy of compressed sensing (CS) reconstructions for specific clinical magnetic resonance neuroimaging applications beyond more conventional acceleration techniques such as parallel imaging (PI) and low-resolution acquisitions.

MATERIALS AND METHODS: Raw k-space data were acquired from five healthy volunteers on a 3T scanner using a 32-channel head coil using T2 -FLAIR, FIESTA-C, time of flight (TOF), and spoiled gradient echo (SPGR) sequences. In a series of blinded studies, three radiologists independently evaluated CS, PI (GRAPPA), and low-resolution images at up to 5× accelerations. Synthetic T2 -FLAIR images with artificial lesions were used to assess diagnostic accuracy for …

Optimization-Based Interactive Segmentation Interface For Multiregion Problems., John S H Baxter, Martin Rajchl, Terry M Peters, Elvis C S Chen

Robarts Imaging Publications

Interactive segmentation is becoming of increasing interest to the medical imaging community in that it combines the positive aspects of both manual and automated segmentation. However, general-purpose tools have been lacking in terms of segmenting multiple regions simultaneously with a high degree of coupling between groups of labels. Hierarchical max-flow segmentation has taken advantage of this coupling for individual applications, but until recently, these algorithms were constrained to a particular hierarchy and could not be considered general-purpose. In a generalized form, the hierarchy for any given segmentation problem is specified in run-time, allowing different hierarchies to be quickly explored. We …

Investigation Of Hippocampal Substructures In Focal Temporal Lobe Epilepsy With And Without Hippocampal Sclerosis At 7t., Brendan G Santyr, Maged Goubran, Jonathan C Lau, Benjamin Y M Kwan, Fateme Salehi, Donald H Lee, Seyed M Mirsattari, Jorge G Burneo, David A Steven, Andrew G Parrent, Sandrine De Ribaupierre, Robert R Hammond, Terry M Peters, Ali R Khan

Robarts Imaging Publications

PURPOSE: To provide a more detailed investigation of hippocampal subfields using 7T magnetic resonance imaging (MRI) for the identification of hippocampal sclerosis in temporal lobe epilepsy (TLE).

MATERIALS AND METHODS: Patients (n = 13) with drug-resistant TLE previously identified by conventional imaging as having hippocampal sclerosis (HS) or not (nine without HS, four HS) and 20 age-matched healthy controls were scanned and compared using a 7T MRI protocol. Using a manual segmentation scheme to delineate hippocampal subfields, subfield-specific volume changes and apparent transverse relaxation rate ( R2*) were studied between the two groups. In addition, qualitative assessment at 7T and …