A target definition based on electroanatomic maps for stereotactic arrhythmia radioablation

Area of Science:

• Cardiology
• Radiation Oncology
• Medical Imaging

Background:

• Accurate target identification is crucial for effective ventricular tachycardia (VT) treatment using stereotactic arrhythmia radioablation (STAR).
• Electroanatomic mapping (EAM) provides detailed 3D cardiac electrical and anatomical data.

Purpose of the Study:

• To assess the feasibility of defining STAR targets by directly co-registering electroanatomic maps (EAMs) with radioablation planning images.
• To establish a method for integrating EAM data into the STAR planning workflow.

Main Methods:

• EAMs were acquired during electrophysiology studies and registered to planning images (MR/CT) using in-house software.
• Non-DICOM EAMs were converted to DICOM structure files for target volume delineation.
• Target volumes were finalized by expert consensus and expanded to internal target volume (ITV) and planning target volume (PTV).
• Treatment involved a single 25 Gy fraction using VMAT or DCAT.

Main Results:

• The direct registration of EAMs to planning images was successfully implemented in seven patients with refractory VT.
• Registration accuracy showed Dice similarity indices of 0.814 ± 0.053 for the left ventricle (LV) and 0.575 ± 0.199 for the left atrium/right ventricle (LA/RV).
• Five out of seven patients experienced a significant reduction in VT events within six weeks post-treatment.

Conclusions:

• The quality of transferred EAMs on MR/CT images was adequate for localizing the VT treatment region.
• The EAM-based direct registration method shows promise for improving STAR efficacy in VT patients.
• Further long-term follow-up is necessary to confirm the safety and efficacy of this approach.