Extended Data Figure 3 : Volumetric and cross-sectional ultrasound imaging and imaging configurations during ex vivo and in vivo imaging.

From: Electromechanical vortex filaments during cardiac fibrillation

Extended Data Figure 3

a, Isolated pig heart in imaging setup with 4D volumetric ultrasound transducer scanning from beneath the heart through an acoustic window, together with simultaneous panoramic fluorescence imaging (Fig. 1). 4D ultrasound imaging (Acuson sc2000, Siemens AG) was performed using a two-dimensional matrix phased-array transducer (4Z1c) producing volume frames with a pyramidal shape (51–188 volumes per second, maximum opening angle 90 × 90 degrees, 6–14 cm lateral depth). The heart is aligned very similarly within the pyramid-shaped field of view as in an examination of a patient in vivo. b, Isolated rabbit heart in imaging setup with 2D cross-sectional ultrasound transducer scanning from above, together with simultaneous single-camera fluorescence imaging (see also d and Supplementary Video 9). c, Imaging configuration during 4D ultrasound imaging and panoramic multi-camera optical mapping with four cameras (see also a). The optical axis of the cameras and the lateral axis of the ultrasound scanner are approximately perpendicular. d, Imaging configuration during 2D ultrasound imaging and single-camera optical mapping (see also b). The optical axis of the camera and the lateral axis of the ultrasound scanner are approximately perpendicular. The cross-sectional ultrasound imaging plane is positioned and aligned tangentially within the ventricular wall underneath and co-planar to the imaged surface. e, Imaging configuration during 3D ultrasound imaging in vivo. In ultrasound examinations of patients, the human heart is either imaged from outside the body through the chest in a transthoracic echocardiography (TTE) examination, or from within the body in a transoesophageal echocardiography examination using a transoesophageal ultrasound probe. The first measurement configuration provides a clearer picture of the ventricles, whereas the latter measurement provides a clearer picture of the atria. We aimed to mimic the TTE measurement imaging the ventricles using a probe that is routinely used in TTE examinations. In a TTE measurement, the transducer may be positioned on the chest below the heart imaging upwards through two ribs or from underneath the ribs. In one of the various views, the apex of the heart is facing the transducer (apical view), as it is located closest to the transducer array. The atria are located furthest away from the transducer array. The imaging configuration used in our experiment is very similar to this situation (a). The size of the human heart is comparable to the size of the pig hearts used in the ex vivoexperiments. f, Frequent imaging configuration during 3D ultrasound imaging with panoramic optical mapping. One camera always imaged the anterior left ventricular wall (similar perspective as in a).