DBP3:Utah:RegCases

Back to Utah AFib DBP

Background

• The CARMA Center uses late gadolinium enhanced MRI (LGE-MRI) images to evaluate new patients, predict procedural success, and evaluate therapeutic outcomes. The MRI images for each patient are further accompanied by MR angiographic images (MRA) and manual segmentations of relevant structures. These images are acquired longitudinally over the course of a patient's evaluation, treatment, and follow-up (i.e. months or years). Registration is often necessary to compare images from different time points in a patient's treatment, across patient cohorts at the same stage of disease progression or treatment, or different image types.

Pre-ablation LGE-MRI Image	Post-ablation LGE-MRI Image	Segmentation of LGE-MRI Image

MRA Image	Immediately Post-ablation (IPA) LGE-MRI Image

Registration Case Types

Pre-ablation LGE to 3 months (or more) post-ablation LGE

• Examine the location of ablation-induced scar formation relative to fibrosis
• Utah score staging of patients [1]

Pre-ablation LGE to Immediately post-ablation(IPA) LGE

• Can compare acute ablation-induced changes to the pre-ablation tissue

Immediately post-ablation to 3 months (or more) post-ablation LGE

• Dark regions on IPA LGE scans result in stable scar formation at 3 or more months post-ablation -> [2]
• Look for gaps in the ablation lesion sets - Ravi's project

Post-ablation LGE to Post-ablation LGE

• Comparing the outcome of repeated ablation procedures to the

Pre-ablation LGE to Pre-ablation LGE

• Comparison across patients prior to ablation

LGE to Dark-blood MRI

• Dark blood images can be used to detect early lesion formation
• Can compare with lesion formation seen later on LGE images

LGE to MRA

• The boundaries of the LA in the MRA mirror the endocardial surface in the LGE scans
• There is the possibility for thresholding the MRA and then registering the segmented region to the LGE

LGE to Electroanatomic map (Carto)

• Compare the low voltage regions of Carto maps to the LGE scans

LGE to CT

• Align LGE and CT for those few patients that have both
• Possibly helpful for correlating volumes and shape in shape analysis studies

Pre-ablation LGE/Endo to Post-ablation LGE/Endo

• Combined the LGE images and manual segmentations can be used to improve the quality of registration
• Yi Gao previously developed a Slicer module to register pre- and post-ablation images driven by the LGE images/segmentations -> AFib Registration & AFib Registration Examples

Implementation

• We need to define a suitable set of registration parameters for each of the above cases
• We will develop a Slicer extension module with the pre-defined registration parameters for each of the above scenarios