# True 4DCT for Quantifying LV Dyssynchrony and Function for Targeting LV Lead Location in CRT

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN DIEGO · 2020 · $861,323

## Abstract

Project Abstract/Summary
Cardiac resynchronization therapy (CRT) is a proven treatment for patients with impaired LV function and a
wide QRS complex. However, approximately 1/3 of patients do not respond to CRT because of suboptimal LV
lead placement yielding persistent dyssynchrony. No large clinical trials have demonstrated that image derived
parameters can differentiate responders from non-responders. Significant intra-observer and inter-vendor
differences in parameters derived from echocardiography have stimulated the search for alternative imaging
methods. We and others have demonstrated that cardiac MRI is an excellent method for measuring
mechanical dyssynchrony and identifying regions of scar through late gadolinium enhancement; hence, MRI
could possibly guide LV lead placement to avoid non-viable tissue and target regions of late mechanical
activation. Unfortunately, a large number of patients considered for CRT have existing pacing systems, or do
not have access to advanced MRI laboratories, severely limiting the possibility of MR guidance. The solution:
Our recent development of a novel high resolution LV function mapping technique called SQUEEZ now allows
us to identify viable LV pacing targets from 4DCT data with a single heartbeat exam. However, the accuracy
and precision of 4DCT for measuring dyssynchrony in the LV is unknown and it is clear that motion artifacts in
4DCT may compromise temporal measurements if left uncorrected. In order to achieve the best temporal
resolution possible, we propose a novel motion correction scheme called “ResyncCT” which reduces the
motion artifacts generated by CT gantry rotation. Our preliminary results lead us to the following hypothesis:
the analysis of “ResyncCT” motion-corrected 4DCT images with SQUEEZ can be used to target optimal
pacing sites to correct LV dyssynchrony with CRT. In order to validate this hypothesis, we will optimize
cardiac cine 4DCT acquisitions and ResyncCT motion compensated reconstruction for measuring LV
dyssynchrony, and we will optimize and validate SQUEEZ in highly realistic anthropomorphic 3D printed
phantoms and in CRT patients. Ultimately, our accuracy in predicting response to CRT will be tested
retrospectively in a series of CRT patients in whom 4DCT data was obtained prior to their CRT procedure. For
each patient, by analyzing their 4DCT data after ResyncCT and SQUEEZ processing, we will compute a novel
“Lead Placement Score” at the site of their LV lead. We will test the hypothesis that the Lead Placement Score
is significantly different in the patients who respond (decrease in End-Systolic Volume > 15% at 6 months) than
in those patients who do not respond to CRT.

## Key facts

- **NIH application ID:** 9846246
- **Project number:** 5R01HL144678-02
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN DIEGO
- **Principal Investigator:** ELLIOT R MCVEIGH
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $861,323
- **Award type:** 5
- **Project period:** 2019-01-15 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9846246

## Citation

> US National Institutes of Health, RePORTER application 9846246, True 4DCT for Quantifying LV Dyssynchrony and Function for Targeting LV Lead Location in CRT (5R01HL144678-02). Retrieved via AI Analytics 2026-06-11 from https://api.ai-analytics.org/grant/nih/9846246. Licensed CC0.

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