The influence of through-plane motion on left ventricular volumes measured by magnetic resonance imaging: implications for image acquisition and analysis.

In the evaluation of the left ventricular (LV) function using magnetic resonance imaging (MRI), a stack of parallel short-axis (SA) cine images is acquired that covers the whole LV. The aim of this study is to quantify the contribution to the LV volume parameters, provided by the most basal image plane that shows the LV wall only in end diastole (ED) but not in end systole (ES). In 57 healthy volunteers (31 men, mean body surface area 1.87 m2), a complete set of parallel SA images was acquired (10-mm slice distance) by breathhold segmented k-space cine MRI (7 ky lines per beat). The LV end-diastolic volume (EDV), stroke volume (SV), ejection fraction (EF), and cardiac output (CO) were determined by slice summation. Calculations were performed both with and without inclusion of the most basal slice. With inclusion of the most basal slice, all parameters were significantly (p < 0.001) larger compared with the values obtained by excluding this slice. EDV was 134 +/- 29 ml versus 113 +/- 26 ml; SV was 93 +/- 18 ml versus 72 +/- 16 ml; EF was 70 +/- 4% versus 64 +/- 4%; and CO was 5.3 +/- 1.4 l/min versus 4.1 +/- 1.1 l/min. The inclusion of the most basal slice leads to significantly larger values of LV volume parameters. Thus, this most basal SA image slice should be included in calculating the EDV. Whether or not this basal SA slice also contributes to the ES volume should be decided by using anatomical criteria on the ES image. The projection line onto the ES image of a long-axis view provides an additional criterion.