Ultrafast power Doppler imaging for RV myocardial perfusion assessment: histopathologic correlation and in vivo...

Area of Science:

• Cardiovascular Imaging
• Medical Ultrasound
• Physiology

Background:

• Assessing myocardial vascular remodeling in right ventricular (RV) pressure overload non-invasively is challenging.
• Attenuation-compensated fractional moving blood volume (acFMBV) using ultrafast power Doppler (UPD) is a novel technique for myocardial blood volume quantification.
• Previous studies have not validated acFMBV in vivo for RV remodeling and capillary density assessment.

Purpose of the Study:

• To quantify RV myocardial blood volume using UPD in rodent models.
• To validate UPD-derived acFMBV with histopathology.
• To assess the feasibility of acFMBV in human patients with RV pressure overload.

Main Methods:

• Twelve rats underwent pulmonary artery banding (PAB) or sham surgery.
• UPD was used to measure RV lateral wall acFMBV, representing myocardial blood volume.
• Capillary density was assessed via CD31 immunostaining and correlated with acFMBV. Human volunteers and patients were also studied.

Main Results:

• PAB rats exhibited significantly lower mid-diastolic acFMBV compared to controls (5.3% ± 0.9% vs. 7.8% ± 1.2%, P < 0.05).
• Reduced acFMBV in PAB rats correlated with decreased capillary density (r = 0.78, P < 0.01).
• Human patients with RV pressure overload showed lower mid-diastolic acFMBV than healthy volunteers (4.8% ± 0.7% vs. 3.1% ± 2.3%, P = 0.03).

Conclusions:

• UPD-based acFMBV is a reliable, non-invasive tool for quantifying RV myocardial blood volume.
• The technique correlates with histological capillary density, supporting its use in assessing RV remodeling.
• Further studies with larger sample sizes are needed to confirm these findings in clinical settings.