125 Once the global translation (xn, yn)and rotation ( n) of the endometrium were obtained through the entire recording, the coordinates of the TMs were updated for each frame n as: / 0R! R1= / cos5R −sin5R sin5R cos5R 1 × / 0R&! !R&!1+ : &R+R; n=2,……., N (2) where N is the total number of frames and (X1,Y1) represents the coordinates of the TMs selected in the first frame, relative to the uterine anatomy. A quantitative measure was introduced to evaluate the quality of the TVUS recordings. Pierson correlation coefficient (PCC) was here used to test the similarity of the speckle patterns between the subsequent frames [24]. The quality of the recording was then determined by the average PCC over all TMs. Recordings with an average PCC >0.8, indicating negligible speckle decorrelation due to OOP motion in subsequent frames, were accepted for further analysis. In the second step, speckle tracking was then applied to TMs. For example, to estimate motion between the (n – 1)th and the nth frames, instead of updating the coordinates of TMs based on their displacements, the coordinates were updated to (Xn ,Yn) according to (2). As a result, speckle tracking is applied only between two subsequent frames. In this way, even if OOP motion caused decorrelation and poor tracking, the tracking error remains limited between two frames without further accumulation. With this approach, tracking is performed for TMs representing consistent anatomical regions, enabling further interpretation of the results as associated with the uterine anatomy and geometry. The author was blinded to the acquisition characteristics, such as the success of IVF treatment and the menstrual phases when positioning the TMs. D. Radial Strain Rate Analysis Strain rate imaging is one of the most widely used approaches for measuring regional or global deformation of the muscle. Therefore, to characterize UP, RSR was derived from both the anterior and posterior walls of the endometrium.
RkJQdWJsaXNoZXIy MTk4NDMw