Sex differences in photon-counting computed tomography findings across hypertrophic phenotypes

Area of Science:

• Cardiovascular Imaging
• Cardiac CT
• Cardiomyopathy Research

Background:

• Photon-counting computed tomography (PCCT) offers comprehensive assessment of left ventricular (LV) morphology, function, and myocardial tissue characteristics.
• The influence of sex on PCCT findings in various hypertrophic phenotypes is not well-established.
• Understanding sex-based differences is crucial for accurate interpretation of cardiac imaging in hypertrophic heart conditions.

Purpose of the Study:

• To investigate sex-based differences in PCCT-derived LV morphology, function, and myocardial tissue characteristics across different hypertrophic phenotypes.
• To evaluate the impact of sex on the agreement between PCCT and cardiovascular magnetic resonance (CMR) findings.
• To assess the consistency of diagnostic thresholds for extracellular volume (ECV) across sexes.

Main Methods:

• Retrospective analysis of 182 adult patients with hypertrophic phenotypes (hypertrophic cardiomyopathy, transthyretin amyloid cardiomyopathy, secondary LVH) undergoing PCCT.
• Assessment of sex differences in PCCT parameters including LV mass index, volumes, ejection fraction (EF), late iodine enhancement (LIE), and ECV.
• Comparison of PCCT and CMR data in 83 patients to evaluate sex effects on CT-CMR agreement for key metrics.

Main Results:

• Overall, women exhibited lower LV mass index, smaller LV volumes, and higher EF compared to men, with slightly lower ECV and LIE extent.
• In hypertrophic cardiomyopathy, sex did not significantly alter wall thickness, LV mass, LIE burden, or ECV.
• In secondary LVH, women showed smaller volumes and higher EF, with comparable tissue characteristics. Transthyretin amyloid cardiomyopathy analysis was limited by small female cohort size but suggested less remodeling and infiltration in women.
• CT-CMR agreement for LV mass, EF, scar extent, and ECV was consistent between sexes, and diagnostic ECV thresholds were robust across genders.

Conclusions:

• Sex influences hypertrophic phenotypes primarily through variations in cardiac remodeling and functional adaptation, rather than substantial differences in myocardial tissue characteristics.
• PCCT is a reliable tool for assessing hypertrophic phenotypes, with consistent diagnostic performance across sexes.
• CT-CMR agreement and diagnostic ECV thresholds are robust, supporting the use of PCCT in diverse patient populations regardless of sex.