Related Experiment Video
Updated: Aug 15, 2026

Quantification of Levator Ani Hiatus Enlargement by Magnetic Resonance Imaging in Males and Females with Pelvic Organ Prolapse
Published on: April 17, 2019
Validation of an automatic method for reconstruction, delineation, and measurement of levator hiatus in clinical
Ying Chen1, Xin Lin1, Man Zhang1
1Department of Ultrasound, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China.
Objectives:
To evaluate the concordance between an automatic software program and manual evaluation in reconstructing, delineating, and measuring the levator hiatus (LH) on maximal Valsalva maneuver.
Methods:
This was a retrospective study analyzing archived raw ultrasound imaging data of 100 patients underwent transperineal ultrasound (TPUS) examination. Each data were assessed by the automatic Smart Pelvic System software program and manual evaluation. The Dice similarity index (DSI), mean absolute distance (MAD), and Hausdorff distance (HDD) were calculated to quantify delineation accuracy of LH. Agreement between automatic and manual measurement of levator hiatus area was assessed by intraclass correlation coefficient (ICC) and Bland-Altman method.
Results:
The satisfaction rate of automatic reconstruction was 94%. Six images were recognized as unsatisfactory reconstructed images for some gas in the rectum and anal canal. Compared with satisfactory reconstructed images, DSI of unsatisfactory reconstructed images was lower, MAD and HDD were larger (p = 0.001, p = 0.001, p = 0.006, respectively). The ICC was up to 0.987 in 94 satisfactory reconstructed images.
Conclusions:
The Smart Pelvic System software program had good performance in reconstruction, delineation, and measurement of LH on maximal Valsalva maneuver in clinical practice, despite misidentification of the border of posterior aspect of LH due to the influence of gas in the rectum.
Related Concept Videos
Distribution Reliability and Automation
The Power Flow Problem and Solution
Three-Phase Short Circuit—Unloaded Synchronous Machine
This behavior occurs due to the magnetic flux produced by the short-circuit armature currents. Initially, these currents follow high-reluctance paths but eventually shift to...
Instrument Transformers
Differential Relays
Multimachine Stability
In analyzing the system, the nodal equations represent the relationship between bus voltages, machine voltages, and machine currents. The nodal equation is given by:

