Four-dimensional (4D) echocardiography: analysis of temporal jitter due to asynchronous image acquisition

Accurate left ventricular (LV) volume quantification in cardiac patient management is considerably important. Two-dimensional (2D) echocardiography causes discrepancies in LV volume measurement due to assumptions on the LV structure and the imaging plane position. 4D echocardiography provides an accurate visual representation of cardiac dynamics in three dimensions. 2D images are reconstructed into 3D images at each cardiac phase, and concatenated to obtain a four dimensional (4D) image. However, current methods of asynchronous image acquisition result in temporal jitter due to random phase shifts in the 3D image. With in vitro studies, we investigated the extent of temporal jitter in 4D echocardiography. 3D images of a myocardial motion phantom were reconstructed and analyzed for different cardiac phases. Our algorithm to quantify temporal jitter consisted of three steps: First, distance maps of the phantom surface from a reference plane were computed. Second, surface variation maps were derived and finally, 2D jitter maps were plotted and color coded to provide a measure of temporal jitter in each 3D image for each cardiac phase. The jitter maps had a standard deviation of 3.5 mm at peak systole and 1.5 mm at end diastole. Jitter of more than 1 mm limits the ability to diagnose cardiovascular disease