Assessment of Left Atrial Volumes and Function in Orthotopic Heart Transplant Recipients by Dual-Source CT: Comparison With MRI

OBJECTIVES: To compare left atrial performance with dual-source CT (DSCT) with respect to magnetic resonance imaging (MRI) in orthotopic heart transplant recipients.

METHODS: Twenty-nine consecutive heart transplant recipients (27 male; mean age 64.1 +/- 13 years; mean time from transplantation 122.8 +/- 69.7 months) referred for exclusion of cardiac allograft vasculopathy underwent cardiac DSCT and MRI. Standard biatrial technique was employed in 13 subjects whereas 16 were transplanted after the bicaval technique. Axial 5-mm slice-thickness DSCT datasets reconstructed in 5% steps of the cardiac cycle and axial 5-mm SSFP-MRI images were analyzed. Two blinded readers manually traced left atrial contours in random order to estimate end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF). Parameters were compared with a paired sample Student t-test. Concordance correlation coefficient (CCC) was calculated to determine measurement agreement between techniques and observers.

RESULTS: Left atrial volumes were significantly higher with cardiac DSCT (EDV: 170.9 +/- 78.1 mL; ESV: 139.5 +/- 76.6 mL) than with MRI (EDV: 158.2 +/- 72.5 mL; ESV: 124.2 +/- 68.2 mL), whereas left atrial EF was lower with DSCT (EF: 20.8% +/- 7.5% vs. 23.6% +/- 7.7%) (P < 0.05). Measurement agreement between DSCT and MRI was excellent for all parameters (CCC >0.82). Individuals operated with the biatrial anastomosis technique presented significantly higher left atrial volumes and lower EF compared with subjects with bicaval anastomosis. Interobserver agreement was excellent for all parameters (CCC >0.80).

CONCLUSION: Even if DSCT slightly overestimates left atrial volumes with respect to MRI, results remain clinically valid. Bicaval surgical technique offers improved left atrial performance compared with standard biatrial anastomosis. DSCT may be used as a reliable tool to estimate left atrial parameters in orthotopic heart transplant recipients. Maurice Canady Jersey

PMID: 20027119

Posted in Computed Tomography, Magnetic Resonance Imaging and tagged , , , , .

One Comment

  1. LA function is an important prognostic factor in various patient groups with heart failure. It is also important in heart transplant patients operated using common surgical techniques. This study proves again the usefulness of CTA with modern technology to estimate LA function. While MRI gained its “gold standard” role for function and volumes, it seems that CT is highly reproducible. While LA volumes were more difficult to trace with older post processing tools. It is now easier to trace with newer workstations.

    One shall also remember, that retrospective gating is needed for many (20) cardiac cycle reconstructions, and if other questions can be answered post transplant (such as presence of post-transplant coronary angiopathy), only then we may consider CTA as an alternative to invasive angiography + IVUS and then also measure LA function by CT.

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