Accuracy of aortic annular measurements obtained from three-dimensional echocardiography, CT and MRI: human in vitro and in vivo studies

Abstract

Objectives To determine the accuracy of calciumcontaining rings measurements imaged by threedimensional echocardiography (3DE), multi-slice CT (MSCT) and cardiac magnetic resonance (CMR) under ideal conditions against the true ring dimensions. To compare the accuracy of aortic annulus (AoA) measurements in ex vivo human hearts using 3DE, MSCT and CMR. To determine the accuracy of AoA measurements in an in vivo human model. Design 3DE, MSCT and CMR imaging were performed on 30 calcium-containing rings and 28 explanted human hearts. Additionally, 15 human subjects with clinical indication for MSCT underwent 3DE. Two experts in each modality measured the images. Main outcome measures Bias and intraclass correlation coefficient for accuracy of imaging measurements when compared with actual ring dimensions. Bias, intraclass correlation coefficient and variability were obtained: (1) when comparing explanted human heart AoA measurements from the two remaining imaging modalities with the most accurate one as determined from the ring measurements and (2) in in vivo human AoA measurements. Analysis was repeated on explanted heart subgroups divided by aortic valve Agatston score. Results Against the known ring dimensions, CMR had the highest accuracy and the lowest variability. MSCT measurements had high accuracy but wider variability and 3DE had the lowest accuracy with the largest variability. When 3DE and MSCT were compared with CMR, 3DE underestimated and MSCT overestimated AoA dimensions, but inter-measurement variability of 3DE and MSCT were similar. When divided by Agatston score, both 3DE and MSCT measurements were larger and showed greater variability with increasing calcium burden. The in vivo study showed that the correlation between 3DE and MSCT measurements was high; however, 3DE measurements were smaller than those measured with MSCT. Conclusions In the in vitro model, CMR measurements were the most accurate for assessing the actual dimensions suggesting that further investigations on its role in AoA measurement in TAVR are needed. However from the in vivo model, MSCT and 3DE are reasonable alternatives with the understanding that they can slightly overestimate and underestimate annular dimensions, respectively.

Aortic Annular Sizing Using a Novel 3-Dimensional Echocardiographic Method

“…Although statistically significant, these differences are not clinically relevant. As suggested in the study by Tsang et al, 10 there may be systematic, methodologic reasons for these differences. Three-dimensional TEE and MDCT clearly have different imaging limitations that may lead to the selection of slightly different transverse planes for annulus assessment.…”

“…16 Cross-sectional 3D-TEE annulus measurements have generally been shown to be smaller than MDCT measurements, 11,23,24,38 and a recent study demonstrated that MDCT overestimated whereas 3D-TEE underestimated in vitro phantom annulus diameters. 10 Using a novel, semiautomated 3D-TEE method with widely available software, our study shows excellent correlation between 3D-TEE and MDCT measurements with a small absolute difference (≤1%), with 3D-TEE measurements underestimating MDCT measurements. Although statistically significant, these differences are not clinically relevant.…”

“…Studies across multiple modalities have also shown the advantages of 3-dimensional (3D) assessment of the annulus compared with 2D assessment. Both echocardiography [7][8][9][10][11] and multidetector row computed tomography (MDCT) 5,6,9,[12][13][14][15][16][17][18][19] have been used for annular sizing before TAVR and have been shown to be predictive of postimplantation paravalvular aortic regurgitation. 7,8,13,18,20 Because transesophageal echocardiography (TEE) is a relatively safe procedure 21,22 that does not require iodinated contrast and can be used intraprocedurally during TAVR, it is desirable to develop reproducible and accurate 3D-TEE measurements of the aortic valve annulus.…”

Aortic annulus measurements: should we use multislice computed tomography, 3D echocardiography or MRI?

“…While most studies concluded that aortic annulus measurements are feasible and reproducible, and reported good intertechnique agreement, it is difficult to draw comparisons and extrapolate the published data to determine the modality of choice, because of the differences in study populations, reference standards and a variety of other factors. The only study that compared the ability of all three imaging modalities, namely MSCT, CMR and 3DE, to quantify aortic annulus geometry was recently published by our group [16]. The complex design of this study, which involved in vitro measurements in manufactured calcium rings and cadaver hearts in addition to human subjects, reflected the difficulties with designing a study that would provide a definitive answer to the question which modality is the best.…”

Transcatheter aortic valve implantation. Expert Consensus of the Association of Cardiovascular Interventions of the Polish Cardiac Society and the Polish Society of Cardio-Thoracic Surgeons, approved by the Board of the Polish Cardiac Society…

“…3D-TEE-derived parameters reproduce results obtained from the heart MSCT. TEE remains a valuable tool in periprocedural monitoring, supporting decision-making on valve sizing, balloon valvuloplasty, and assessment of PVL [56,57].…”