Noparatkailas Nabhat, Saprungruang Ankavipar, Sanguanwong Piyanun, Sunthornram Angkana, Vorasettakarnkij Yongkasem, Tumkosit Monravee, Chattranukulchai Pairoj, Theerasuwipakorn Nonthikorn
Division of Cardiology, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
Division of Pediatric Cardiology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Bangkok, Thailand.
BMC Med Imaging. 2025 May 14;25(1):160. doi: 10.1186/s12880-025-01708-y.
The stack-of-short-axis volumes (SAX) summation and single-plane area-length (AL) methods are established approaches for right atrial (RA) volume quantification in cardiovascular magnetic resonance (CMR) imaging. However, data regarding the reliability and agreement between these methods are limited. Furthermore, there is no validation on whether to include the right atrial appendage (RAA) in the analysis. This study aims to evaluate the reliability of the single-plane AL and SAX methods for measuring RA volumes and to assess the agreement between these two approaches.
CMR (3.0T, Siemens) data from 40 healthy volunteers were analyzed to quantify RA volumes, both including and excluding RAA volume, using the SAX and single-plane (4-chamber view) AL methods.
The mean age of 40 participants was 33.6 ± 6.1 years (50% male). RA volumes measured by the SAX method were significantly larger than those obtained by the single-plane AL method (maximum RA volume including RAA: 84.9 ± 22.9 vs. 63.7 ± 16.0 ml, p-value < 0.001; minimum RA volume including RAA: 45.3 ± 15.9 vs. 34.7 ± 12.2 ml, p-value < 0.001). RA ejection fraction (RAEF) was the only parameter that showed no statistical difference between the two methods. Bland-Altman plots demonstrated poor agreement between the techniques, with substantial biases and wide limits of agreement. Both methods exhibited excellent reproducibility when the RAA volume was included (ICC = 0.89-0.96). However, reproducibility was reduced when the RAA volume was excluded, particularly in terms of inter-observer agreement (ICC = 0.73-0.96).
The single-plane AL method underestimates RA volumes compared to the SAX method, and the poor agreement between the two techniques suggests they should not be used interchangeably. RA volume measurements should be interpreted using method-specific reference values. Additionally, including the RAA in RA volume quantification-regardless of the method-may improve measurement reproducibility.
短轴容积（SAX）叠加法和单平面面积-长度（AL）法是心血管磁共振（CMR）成像中右心房（RA）容积定量的既定方法。然而，关于这些方法之间的可靠性和一致性的数据有限。此外，对于分析中是否纳入右心耳（RAA）尚无验证。本研究旨在评估单平面AL法和SAX法测量RA容积的可靠性，并评估这两种方法之间的一致性。
分析40名健康志愿者的CMR（3.0T，西门子）数据，使用SAX法和单平面（四腔心视图）AL法对RA容积进行定量，包括和不包括RAA容积。
40名参与者的平均年龄为33.6±6.1岁（50%为男性）。SAX法测量的RA容积显著大于单平面AL法测量的RA容积（包括RAA的最大RA容积：84.9±22.9 vs. 63.7±16.0 ml，p值<0.001；包括RAA的最小RA容积：45.3±15.9 vs. 34.7±12.2 ml，p值<0.001）。RA射血分数（RAEF）是两种方法之间唯一无统计学差异的参数。Bland-Altman图显示两种技术之间的一致性较差，存在显著偏差和较宽的一致性界限。当纳入RAA容积时，两种方法均表现出出色的可重复性（组内相关系数ICC = 0.89 - 0.96）。然而，当排除RAA容积时，可重复性降低，尤其是在观察者间一致性方面（ICC = 0.73 - 0.96）。
与SAX法相比，单平面AL法低估了RA容积，两种技术之间较差的一致性表明它们不应互换使用。RA容积测量应使用特定方法的参考值进行解释。此外，无论采用何种方法，在RA容积定量中纳入RAA可能会提高测量的可重复性。
