Ultrasonic strain imaging systems are gaining rapid attention for breast tumor differentiation, despite the fact that consistently obtaining high quality in vivo strain images is a persistent challenge. To enhance the clinical usability of such systems, much effort has been devoted to developing more sophisticated motion tracking algorithms. This study takes an alternate route to investigate a new strain formation scheme for improving in vivo strain image quality. This method is a retrospective processing technique that is not restricted to a particular motion tracking algorithm. A block-matching algorithm was used in this study for our convenience. Radiofrequency (RF) echo data acquired from a Siemens Elegra with freehand scanning of in vivo breast tissue were used to validate this method. Through processing of in vivo breast tissue data (7 data sets with different types of lesions and roughly 700 RF echo frames in total), our findings demonstrate that higher quality strain images can be obtained through the proposed retrospective pairing technique