Characteristics of the left ventricular three-dimensional maximum principal strain using cardiac computed tomography:...

Area of Science:

• Cardiovascular Imaging
• Cardiac Mechanics
• Radiology

Background:

• Assessing left ventricular (LV) function is crucial in cardiology.
• Left ventricular maximum principal strain (LV-MPS) quantifies myocardial deformation.
• Cardiac CT (computed tomography) offers potential for strain analysis.

Purpose of the Study:

• To evaluate the characteristics of LV-MPS using cardiac CT in individuals with normal LV function.
• To assess the reproducibility of CT-derived LV-MPS measurements.
• To investigate regional variations in LV-MPS across different LV levels and walls.

Main Methods:

• Retrospective analysis of 31 subjects with normal LV function (ejection fraction ≥55%) who underwent ECG-gated cardiac CT.
• CT images were reconstructed at 5% intervals of the RR cycle.
• LV-MPS and time to peak (TTP) were analyzed using a 16-segment model.
• Intra- and inter-observer reproducibility was assessed using intraclass correlation coefficients (ICCs).

Main Results:

• High intra- and inter-observer reproducibility for peak LV-MPS (ICCs 0.96 and 0.94, respectively).
• Global peak LV-MPS was 0.59.
• LV-MPS significantly increased from base (0.54) to mid (0.57) to apex (0.68).
• The lateral wall showed significantly higher LV-MPS (0.66) compared to the septum (0.47).
• No significant difference in TTP was observed across regions or levels.

Conclusions:

• CT-derived LV-MPS is a reproducible method for quantitative assessment of myocardial contraction.
• In subjects with normal cardiac function, LV-MPS exhibits heterogeneity, being highest at the apex and lateral wall and lowest in the septum.
• Cardiac CT can reveal synchronized myocardial contraction despite regional strain variations in healthy individuals.