Left ventricle segment-specific motion assessment for cardiac-gated radiosurgery

Area of Science:

• Cardiovascular Imaging and Intervention
• Radiation Oncology
• Cardiac Electrophysiology

Background:

• Cardiac radiosurgery offers a non-invasive approach for treating ventricular tachycardia.
• Accurate targeting of arrhythmogenic regions is crucial for treatment efficacy.
• Understanding cardiac motion is essential for optimizing radiation delivery.

Purpose of the Study:

• To quantify left ventricle (LV) segment-specific motion using cardiac magnetic resonance (CMR) cine images.
• To assess the potential benefits of cardiac-gated radiosurgery by analyzing motion during the cardiac cycle.
• To evaluate segment-specific motion variations in controls and heart failure patients with reduced ejection fraction (HFrEF).

Main Methods:

• Analysis of CMR breath-hold cine images and LV contour points in 50 controls and 50 HFrEF patients.
• Division of contour points into 17 anatomic segments to define hypothetical treatment targets.
• Determination of optimal treatment windows and measurement of centroid displacement and treatment areas with and without cardiac gating.

Main Results:

• Full motion centroid displacements ranged from 6-14 mm (controls) and 4-11 mm (HFrEF).
• Cardiac gating reduced centroid displacements to 1 mm in both groups.
• Cardiac gating significantly reduced treatment areas by 38%-53% in controls and 26%-48% in HFrEF patients.

Conclusions:

• Cardiac cycle motion is a significant factor in overall target motion for cardiac radiosurgery.
• Segment-specific cardiac motion varies across different anatomic regions of the heart.
• Cardiac gating has the potential to substantially decrease treatment volumes, enhancing the precision of cardiac radiosurgery.