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Session: Soft Tissue & Abdominal Organs
Session starts: Thursday 24 January, 13:30
Presentation starts: 13:45
Room: Lecture room 559

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Yizhou Huang (Eindhoven University of Technology)
Federica Sammali ()
Celine Blank ()
Nienke Kuijsters ()
Chiara Rabotti ()
Dick Schoot ()
Massimo Mischi ()

Abstract:
Uterine peristalsis (UP) plays an important role in the generation of intrauterine streams; upstream towards the ovaries to support conception and downstream to favor menstrual emptying. Our understanding of the uterine mechanical behavior is however hampered by a lack of quantitative analysis, limiting identification and treatment of uterine dysfunctions. Building on our recent work on dedicated speckle tracking for uterine strain analysis, here we present the first algorithm for spatiotemporal assessment of UP. In particular, we aim at characterizing the propagation of contraction waves along the uterus. Eleven women were scanned with B-mode transvaginal ultrasound during the late follicular phase, which coincides with the fertile period and is known to be the most active phase [1]. The speckle was tracked on the gray-level videos by optical flow. The method accuracy was further improved by an adaptive spatial-warping approach. The method was first optimized and validated with a dedicated setup producing controlled motion of an ex-vivo uterus [2]. In vivo, a grid of points was positioned around the endometrium and tracked over time. The strain rate of uterine muscle was then extracted to generate a time-space representation. This was analyzed in the 2D Fourier domain for the assessment of UP (contraction wave) speed and direction, determined by the two dominant spectral peaks. The ex-vivo results confirmed the accuracy of the implemented adaptive optical flow method for uterine speckle tracking. In vivo, different propagation directions were observed. The estimated UP speed was 0.88 ± 0.28 mm/s (upstream) and 1.27 ± 0.69 mm/s (downstream), which is in line with the literature based on visual inspection [3]. These promising results represent a first step towards a better characterization and understanding of UP. Extended studies with more patients will elucidate on the actual limits of the method, and the role it can play in clinical practice, with emphasis on fertilization procedures.