Evaluation of the right ventricle: comparison of gated blood-pool single photon electron computed tomography and echocardiography with cardiac magnetic resonance

Background: The evaluation of the right ventricle (RV) is a challenge; as a result six transthoracic echocardiography (TTE) parameters have been suggested. While gated blood-pool single photon electron computed tomography (GBPS) is a promising technique, there is currently no completely automated and validated processing software available clinically. Consequently, cardiac magnetic resonance (CMR) imaging remains the gold standard for RV assessment. We aimed to compare RV evaluation by GBPS and TTE to CMR.

Methods: Fifty-eight patients underwent CMR, GBPS and TTE for RV assessment, including volumes, RVEF and TTE's indices of RV function (fractional area change (FAC), RV myocardial performance index by pulsed wave Doppler (MPI-PWD) and tissue Doppler (MPI-TDI) and tricuspid annular plane systolic excursion (TAPSE) by M-Mode and tissue Doppler (TAPSE-TDI)). GBPS was performed using both a commercial (QBS) and the Montreal Heart Institute (MHI) proprietary software.

Results: Nuclear medicine derived volumes quantification showed very good correlations with CMR, for RV end-diastolic (r=0.84 and 0.77, all p<0.001) and end-systolic (r=0.82 and 0.67, all p<0.001) volumes by MHI and QBS software respectively. RVEF showed a significant correlation with CMR in patients with RVEF ≤ 45% (r=0.54, p=0.029 and r=0.55, p=0.028, by MHI and QBS respectively). Among TTE parameters, only FAC and MPI-TDI were significantly correlated with CMR-RVEF, mainly for RVEF ≤ 45% (r=0.63, p=0.011 and r=0.58, p=0.046).

Conclusions: GBPS, both with MHI and QBS software, exhibited significant correlations with CMR for evaluation of the RV (volumes and decreased RVEF estimation). Among TTE's parameters, only FAC and MPI-TDI showed significant correlation with CMR with RVEF ≤ 45%.