Determination of right ventricular volume and function using multiple axially rotated MRI slices

Area of Science:

• Cardiovascular Imaging
• Medical Physics
• Radiology

Background:

• Conventional short-axis (SA) magnetic resonance imaging (MRI) for right ventricular (RV) assessment is limited by complex RV anatomy and shape.
• The rotated long axis (RLA) orientation is proposed to overcome these limitations.

Purpose of the Study:

• To evaluate the efficacy of the RLA orientation for RV volume and motion analysis using MRI.
• To compare the RLA method with the conventional SA orientation in phantoms and healthy volunteers.

Main Methods:

• Three phantoms and 23 healthy male volunteers were scanned using cine balanced steady-state free precession MRI.
• Both SA and RLA orientations were acquired with identical imaging parameters.
• RV volumes (end-diastolic, end-systolic, stroke volume) were calculated from segmented images.

Main Results:

• No significant differences in RV volumes were found between RLA and SA orientations (P > 0.17).
• Interobserver and intraobserver variability were comparable for both methods (2.8%–6.8%).
• The SA method required consensus on basal slice definition in 39% of volunteers, impacting volume accuracy.

Conclusions:

• The RLA method offers superior visualization of the RV inflow, outflow, and apex.
• RLA orientation enhances accurate RV volume measurement for diagnosing and monitoring cardiac diseases.
• Despite requiring slightly longer acquisition time, RLA is a valuable tool for RV assessment.