Deep learning enables automatic quantitative assessment of puborectalis muscle and urogenital hiatus in plane of minimal hiatal dimensions.

OBJECTIVES: To measure the length, width and area of the urogenital hiatus (UH), and the length and mean echogenicity (MEP) of the puborectalis muscle (PRM), automatically and observer-independently, in the plane of minimal hiatal dimensions on transperineal ultrasound (TPUS) images, by automatic segmentation of the UH and the PRM using deep learning. METHODS: In 1318 three- and four-dimensional (3D/4D) TPUS volume datasets from 253 nulliparae at 12 and 36 weeks' gestation, two-dimensional (2D) images in the plane of minimal hiatal dimensions with the PRM at rest, on maximum contraction and on maximum Valsalva maneuver, were obtained manually and the UH and PRM were segmented manually. In total, 713 of the images were used to train a convolutional neural network (CNN) to segment automatically the UH and PRM in the plane of minimal hiatal dimensions. In the remainder of the dataset (test set 1 (TS1); 601 images, four having been excluded), the performance of the CNN was evaluated by comparing automatic and manual segmentations. The performance of the CNN was also tested on 117 images from an independent dataset (test set 2 (TS2); two images having been excluded) from 40 nulliparae at 12 weeks' gestation, which were acquired and segmented manually by a different observer. The success of automatic segmentation was assessed visually. Based on the CNN segmentations, the following clinically relevant parameters were measured: the length, width and area of the UH, the length of the PRM and MEP. The overlap (Dice similarity index (DSI)) and surface distance (mean absolute distance (MAD) and Hausdorff distance (HDD)) between manual and CNN segmentations were measured to investigate their similarity. For the measured clinically relevant parameters, the intraclass correlation coefficients (ICCs) between manual and CNN results were determined. RESULTS: Fully automatic CNN segmentation was successful in 99.0% and 93.2% of images in TS1 and TS2, respectively. DSI, MAD and HDD showed good overlap and distance between manual and CNN segmentations in both test sets. This was reflected in the respective ICC values in TS1 and TS2 for the length (0.96 and 0.95), width (0.77 and 0.87) and area (0.96 and 0.91) of the UH, the length of the PRM (0.87 and 0.73) and MEP (0.95 and 0.97), which showed good to very good agreement. CONCLUSION: Deep learning can be used to segment automatically and reliably the PRM and UH on 2D ultrasound images of the nulliparous pelvic floor in the plane of minimal hiatal dimensions. These segmentations can be used to measure reliably UH dimensions as well as PRM length and MEP. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Ultrasound Assessment of Abdominal Muscle Thickness in Women With and Without Low Back Pain During Pregnancy.

OBJECTIVE: The aim of this preliminary study was to determine the differences in abdominal musculature thickness, within 1 month of delivery, in women who experienced back pain during pregnancy compared with those who did not. METHODS: B-mode ultrasound imaging was used to measure abdominal muscle thickness on 76 postpartum participants who participated in a larger study; 47 women experienced back pain during pregnancy, and 29 did not. Participant data were stratified by group, and primary comparisons were based on these grouping across the abdominal muscles, including rectus abdominis (upper and lower fibers), external oblique, internal oblique, and transversus abdominis. Means and standard deviations were also used to set parameters for future studies. RESULTS: In the present study, there was no difference in any abdominal muscle thickness between groups. Women with low back pain were significantly shorter (165.19 ± 6.64 cm) than women who did not have from back pain during pregnancy (169.38 ± 7.58 cm). All other demographics, such as age, weight, and date tested postpartum, were not significantly different between groups. CONCLUSION: The results of this study showed no variation in abdominal muscle thickness in women who had back pain during pregnancy and those who did not.

Assessment of transverse abdominal muscle symmetry by ultrasonography.

BACKGROUND: One of the methods of assessing the transverse abdominal muscle is ultrasonography, which visualizes its thickness and location. We set out to answer the question if the transverse abdominal muscle can always be treated as located symmetrically among the trunk structures. MATERIAL AND METHODS: A group of 113 volunteers took part in the study. The volunteers did not experience any severe pain of musculoskeletal structures as determined by the VAS and ODI scales. The location of the transverse abdominal muscle (TRA) was determined with a Honda NS 2100 ultrasound system. Basing on original methodology, the distance between the place where the transverse abdominal muscle tendon becomes the muscle belly and the linea alba was measured. The next stage was the assessment of correlation of pain. RESULTS: The results in the study group show a statistically significant difference in the distance between the place where the transverse abdominal muscle tendon becomes the muscle belly and the linea alba between left and right. No correlation was found between the asymmetry and pain intensity. CONCLUSIONS: 1. Differences in the distance between the transverse abdominal muscle and the linea alba on left and right side of the body were discovered in the study group. 2. No correlations were found between the presence of an asymmetry and lumbar pain in the study group.

Analysis of the abdominal musculo-aponeurotic anatomy in rectus diastasis: comparison of CT scanning and preoperative clinical assessment with direct measurement intraoperatively.

PURPOSE: To evaluate and compare the consistency of agreement of two methods for measuring abdominal rectus diastasis (ARD), preoperative computed tomography (CT) scanning and preoperative clinical assessment were compared with direct measurement intraoperatively. METHODS: Fifty-five consecutive patients were retrieved from an ongoing prospective randomised trial comparing two operative techniques for the repair of ARD. All patients underwent a preoperative clinical assessment and CT scan, and the results were compared with intraoperative measurement of the ARD width. Agreement between methods was described with Bland-Altman plots (BA plots) and calculated using Lin's Concordance Correlation Coefficient (CCC). RESULTS: The median width of the diastasis was 4.0 cm in the upper midline and 3.0 cm in the lower midline for the intraoperative measurement. BA plots showed that measurements on CT and intraoperatively are not in agreement in the lower midline, whereas the agreement was stronger between the clinical and the intraoperative method. The CCC was higher for clinical vs. intraoperative measurement (0.479) than for CT vs. intraoperative measurement (-0.002) in the lower midline, although the agreement was over all low. CT scanning underestimated the width of the ARD when compared to 87 % of preoperative clinical assessments, and 83 % of intraoperative measurements. Preoperative clinical assessment overestimated ARD in 35 % when compared with intraoperative measurements. CONCLUSION: Clinical assessment prior to surgery provides more accurate information than CT scanning in the assessment of ARD width. CT scanning underestimates ARD width when compared with intraoperative measurement.

Relationship between ultrasonography and electromyography measurement of abdominal muscles when activated with and without pelvis floor muscles contraction.

AIM: The importance of the abdominal musculature in spine stability, has promoted the development of a variety of studies. Ultrasound imaging (UI) is a valuable tool which, when applied appropriately, has the potential to provide significant insight into abdominal muscle contraction. Limited studies have been taken place regarding the relationship between ultrasound measures of muscle thickening and electromyography (EMG) measures of activation. Inconsistent results, however, have been reported. Based on previous studies association between abdominal muscle activation and thickening may be affected by contraction level. The aims of this study were to measure the relationship between abdominal muscle thickness and abdominal muscles amplitude in different levels of abdominal muscles contraction. METHODS: The research was carried on with a convenience sampling at the Physical Therapy Department of University of Social Welfare and Rehabilitation Sciences. Thirty healthy participants volunteered for this study. Muscle thickness right transversus abdominis (TrA) and obliqus internus (OI) muscles in abdominal hallowing maneuvers with and without pelvic floor muscle (PFM) contraction has been measured. Additionally, surface EMG of the right TrA/IO muscles was recorded. A hardware electrical part that acts as trigger system was used to record the activities of abdominal muscles in UI and EMG synchronously. Thickness change, normalized thickness and maximum amplitude abdominal muscles were used for statistical analysis. RESULTS: Correlations between the thickness change and amplitude measures were -0.03 -- 0.38 for TrA/IO. The Correlations between the normalized thickness and amplitude measures were -0.04--0.26 for TrA/IO. CONCLUSION: There is not clear relationship between increases in abdominal muscle activation and corresponding measures of thickening during abdominal muscle contraction. Changes in thickness of deep abdominal muscle cannot be used to indicate changes in the electrical activity in this muscle.

Architectural and morphological assessment of rat abdominal wall muscles: comparison for use as a human model.

The abdominal wall is a composite of muscles that are important for the mechanical stability of the spine and pelvis. Tremendous clinical attention is given to these muscles, yet little is known about how they function in isolation or how they interact with one another. Given the morphological, vascular, and innervation complexities associated with these muscles and their proximity to the internal organs, an appropriate animal model is important for understanding their physiological and mechanical significance during function. To determine the extent to which the rat abdominal wall resembles that of human, 10 adult male Sprague-Dawley rats were killed and formalin-fixed for architectural and morphological analyses of the four abdominal wall muscles (rectus abdominis, external oblique, internal oblique, and transversus abdominis). Physiological cross-sectional areas and optimal fascicle lengths demonstrated a pattern that was similar to human abdominal wall muscles. In addition, sarcomere lengths measured in the neutral spine posture were similar to human in their relation to optimal sarcomere length. These data indicate that the force-generating and length change capabilities of these muscles, relative to one another, are similar in rat and human. Finally, the fiber lines of action of each abdominal muscle were similar to human over most of the abdominal wall. The main exception was in the lower abdominal region (inferior to the pelvic crest), where the external oblique becomes aponeurotic in human but continues as muscle fibers into its pelvic insertion in the rat. We conclude that, based on the morphology and architecture of the abdominal wall muscles, the adult male Sprague-Dawley rat is a good candidate for a model representation of human, particularly in the middle and upper abdominal wall regions.

Magnetic resonance imaging (MRI) for assessment of differences in geometrical parameters in muscles stabilizing vertebral column in young and older persons. Case study.

Today non-traumatic low back pain (LBP) is a social disease being attributed to weakening the function of abdominal and back muscles. Condition of deep muscles, inaccessible to non-invasive examinations, can be assessed by means of magnetic resonance imaging (MRI). The method allows for the assessment of cross-sections, muscle girths, as well as their intensity (brightness). The aim of the investigations was to determine the opportunities to employ MRI technique for assessing the geometry of muscles which stabilize spinal column. The study covered 4 women without LBP symptoms. The cross-sectional area, thickness and brightness of abdominal and back muscles were measured at the level of L3-L4. Measurement of geometrical parameters in the positions studied was aimed at setting such measurement conditions that would force higher isometric contraction in the muscles examined. As a result of measurements it can be inferred that other conditions of the experiment affect neither an increase in cross-sectional surface area nor the thickness of the muscles examined. The differences observed in geometrical parameters of the muscles testify to different coordination of muscle activation in the positions studied, both in young and older subjects, and to the purposefulness of continuing this type of measurements.

Muscle thickness changes during abdominal hollowing: an assessment of between-day measurement error in controls and patients with chronic low back pain.

Spine stabilization exercises, in which patients are taught to perform isolated contractions of the transverses abdominus (TrA) during "abdominal hollowing", are a popular physiotherapeutic treatment for low back pain (LBP). Successful performance is typically judged by the relative increase in TrA thickness compared with that of the internal (OI) and external (OE) oblique muscles, measured using ultrasound. The day-to-day measurement error (imprecision) associated with these indices of preferential activation has not been assessed but is important to know since it influences the interpretation of changes after treatment. On 2 separate days, 14 controls and 14 patients with chronic LBP (cLBP) performed abdominal hollowing exercises in hook-lying, while M-mode ultrasound images superimposed with tissue Doppler imaging (TDI) data were recorded from the abdominal muscles (N = 5 on each side). The fascial lines bordering the TrA, OI and OE were digitized, and muscle thicknesses were calculated. The between-day error (intra-observer) was expressed as the standard error of measurement, SEM; SEM as a percentage of the mean gave the coefficient of variation (CV). There were no significant between-day differences for the mean values of resting or maximal thickness for any muscle, in either group (P > 0.05). The median SEM and CV of all thickness variables was 0.71 mm and 10.9%, respectively for the controls and 0.80 mm or 11.3%, respectively for the cLBP patients. For the contraction ratios (muscle thickness contracted/thickness at rest), the CVs were 3-11% (controls) and 5-12% (patients). The CVs were unacceptably high (30-50%, both groups) for the TrA preferential activation ratio (TrA proportion of the total lateral abdominal muscle thickness when contracted minus at rest). In both the controls and patients, the precision of measurement of absolute muscle thickness and relative change in thickness during abdominal hollowing was acceptable, and commensurate with that typical of biological measurements. The TrA preferential activation ratio is too imprecise to be of clinical use. Knowledge of the SEM for these indices is essential for interpreting the clinical relevance of any changes observed following physiotherapy.

The influence of anatomical boundaries, age, and sex on the assessment of abdominal visceral fat.

Single-slice abdominal computed tomography (CT) scanning has been used extensively for the measurement of abdominal visceral fat (AVF). Optimal anatomical scan location and pixel density ranges have been proposed and are specifically reported to allow for the replication and standardization of AVF measurements. Standardization of the anatomical boundaries for CT measurement of AVF and the influence of age and gender on results obtained with different boundary locations have received much less attention. To determine the influence of three boundary analysis methods (AVF-1, AVF-2, and AVF-3) on the measurement of AVF by CT, 54 older (60 years to 79 years) and 37 younger (20 years to 29 years) healthy men and women were examined. The measurement boundary for AVF-1 was the internal most aspect of the abdominal and oblique muscle walls, and the posterior aspect of the vertebral body. AVF-2 used fat measurements enclosed in a boundary formed by the midpoint of the abdominal and oblique muscle walls, and the most posterior aspect of the spinous process. AVF-3 used fat measurements enclosed in a boundary formed by the external border of the abdominal and oblique muscle walls, and the external border of the erector spinae. Greater AVF measures were obtained with AVF-2 and AVF-3 compared with AVF-1 (p < 0.0001). These differences were greater in older compared with younger subjects (p < 0.0001) and greater in women compared with men (p < 0.02). The significantly greater AVF measurements obtained with AVF-2 and AVF-3 resulted from the inclusion of larger amounts of fat that are not drained by the portal circulation. This included retroperitoneal, intermuscular, and intramuscular lipid droplets, which increase with aging. On the basis of these results, we recommend the AVF-1 anatomical boundaries for the measurement of AVF in clinical investigations, particularly with older subjects. These data demonstrate the importance of precise and reproducible anatomical boundaries for the measurement of AVF, particularly in longitudinal studies.