Recent studies have shown that the extramuscular connective tissue (ECT) is thickened and stiffened in delayed onset muscle soreness (DOMS). However, contrarily to the normal population, severe DOMS is rare in athletes or highly trained individuals. The present randomized, controlled trial therefore aimed to investigate pain as well as microcirculation and stiffness of the ECT and the erector spinae muscle following submaximal eccentric trunk extension exercise not causing DOMS. The effect of manual treatment by a therapist (myofascial release; MFR) on these parameters was to be studied. Trained healthy participants (n = 21; 31.3 ± 9.6 years; > 4 h exercise per week) performed submaximal eccentric exercise of the trunk extensors. One group was manually treated (n = 11), while the other group (n = 10) received placebo treatment with sham laser therapy. Stiffness of the ECT and the erector spinae muscle (shear wave elastography), microcirculation (white light and laser Doppler spectroscopy), palpation pain (100 mm visual analogue scale, VAS) and pressure pain threshold (indentometry, PPT) were assessed before (t0), 24 h (t24) and 48 h (t48) after conditions. Erector spinae muscle stiffness increased after eccentric exercise from t0 to t24 (0.875 m/s) and from t0 to t48 (0.869 m/s). After MFR, erector spinae muscle stiffness decreased in contrast to placebo treatment at t24 (-0.66 m/s), while ECT stiffness remained unchanged. Oxygen saturation increased (17-20.93%) and relative haemoglobin decreased (-9.1 - -12.76 AU) after eccentric exercise and MFR differed from placebo treatment at t48 (-3.71 AU). PPT differed after MFR from placebo treatment at t48 (20.69 N/mm), while VAS remained unchanged. Multiple linear regression showed that ECT stiffness and group membership predicted erector spinae muscle stiffness. MFR could have a positive effect on pain, microcirculation and muscle stiffness after submaximal eccentric exercise, suggesting better recovery, which needs to be confirmed by future work.

Histotripsy is a noninvasive focused ultrasound therapy that mechanically fractionates tissue to create well-defined lesions. In a previous clinical pilot trial to treat benign prostatic hyperplasia (BPH), histotripsy did not result in consistent objective improvements in symptoms, potentially because of the fibrotic and mechanically tough nature of this tissue. In this study, we aimed to identify the dosage required to homogenize BPH tissue by different histotripsy modalities, including boiling histotripsy (BH) and cavitation histotripsy (CH). A method for histotripsy lesion quantification via entropy (HLQE) analysis was developed and utilized to quantify lesion area of the respective treatments. These data were correlated to changes in mechanical stiffness measured by ultrasound shear-wave elastography before and after treatment with each parameter set and dose. Time points corresponding to histologically observed complete lesions were qualitatively evaluated and quantitatively measured. For the BH treatment, complete lesions occurred with >  = 30 s treatment time, with a corresponding maximum reduction in stiffness of -90.9 ± 7.2(s.d.)%. High pulse repetition frequency (PRF) CH achieved a similar reduction to that of BH at 288 s (-91.6 ± 6.0(s.d.)%), and low-PRF CH achieved a (-82.1 ± 5.1(s.d.)%) reduction in stiffness at dose >  = 144 s. Receiver operating characteristic curve analysis showed that a >  ~ 75% reduction in stiffness positively correlated with complete lesions observed histologically, and can provide an alternative metric to track treatment progression.

BACKGROUND: Perianal fistulas pose dual challenges to Crohn\'s disease (CD) patients. Low patient compliance due to the complexity of existing examination methods plagues the treatment and follow-up management of perianal CD.
OBJECTIVE: To determine the accuracy of endoanal ultrasound (EUS) and shear wave elastography (SWE) for evaluating perianal fistulizing CD (PFCD) activity.
METHODS: This was a retrospective cohort study. A total of 67 patients from August 2022 to December 2023 diagnosed with CD were divided into three groups: Non-anal fistula group (n = 23), low-activity perianal fistulas [n = 19, perianal disease activity index (PDAI) ≤ 4], high-activity perianal fistulas (n = 25, PDAI > 4) based on the PDAI. All patients underwent assessments including EUS + SWE, pelvic magnetic resonance [pelvic magnetic resonance imaging (MRI)], C-reactive protein, fecal calprotectin, CD activity index, PDAI.
RESULTS: The percentage of fistulas indicated by pelvic MRI and EUS was consistent at 82%, and there was good consistency in the classification of perianal fistulas (Kappa = 0.752, P < 0.001). Significant differences were observed in the blood flow Limberg score (χ 2 = 8.903, P < 0.05) and shear wave velocity (t = 2.467, P < 0.05) between group 2 and 3. Shear wave velocity showed a strong negative correlation with magnetic resonance novel index for fistula imaging in CD (Magnifi-CD) score (r = -0.676, P < 0.001), a weak negative correlation with the PDAI score (r = -0.386, P < 0.05), and a weak correlation between the Limberg score and the PDAI score (r = 0.368, P < 0.05).
CONCLUSIONS: EUS combined with SWE offers a superior method for detecting and quantitating the activity of perianal fistulas in CD patients. It may be the ideal tool to assess PFCD activity objectively for management strategies.

Background: Ultrasound shear wave elastography (SWE) noninvasively measures the stiffness of tissue by producing and measuring tissue deformation. Scar formation, a crucial aspect of wound healing, can lead to functional and aesthetic complications when pathological. While SWE has shown promise in dermatological evaluations, its role in surgical scar assessment remains underestimated. Our study aims to investigate SWE in evaluating surgical scars at the donor site after forearm free flap surgery in transgender patients. Methods: After radial forearm free flap harvesting, the donor site was grafted with a split-thickness skin graft with or without interposition of Matriderm. Eleven patients were evaluated more than one year after surgery, using SWE alongside scar characteristics, sensory outcomes, and patient satisfaction surveys. Results: Our study revealed no significant difference in stiffness (p > 0.15), pigmentation (p = 0.32), or erythema (p = 0.06) between operated and non-operated sides. The interposition of Matriderm did not influence the stiffness. Patients significantly (p < 0.0001) reported a loss of discrimination. Patients\' subjective scar evaluation appeared in line with our quantitative and objective results. Conclusions: This study contributes to the evolving understanding of SWE\'s role in scar assessment, highlighting its feasibility in evaluating surgical scars. However, continued research efforts are necessary to establish SWE as a reliable and objective method for surgical scar evaluation and management.

UNASSIGNED: To validate the feasibility of ultrasound in assessing the curative effect of botulinum toxin type A (BTXA) in treating hypertrophic scar (HS).
UNASSIGNED: Eight healthy New Zealand long-eared rabbits were utilized in the study. Four wounds, each measuring 1.0 cm in diameter, were created on both ears of each rabbit. Immediately after surgery, each of these wounds received an injection containing a distinct concentration of BTXA. On postoperative week 6, scar thickness, vascularity, and hardness were assessed based on high frequency ultrasound (HFUS), superb microvascular imaging (SMI), shear wave elastography (SWE), Masson staining, and immunohistochemical staining for CD31.
UNASSIGNED: All wounds healed well, and HSs formed after 6 weeks post-surgery. Scar thickness based on HFUS presented a significant decrease with increasing BTXA concentration (p < 0.05), aligning with the gross morphology. Simultaneously, scar stiffness, evaluated using SWE, showed a significant decrease in accordance with the variation of the collagen volume fraction, which refers to the ratio of the collagen positive area to the total area (p < 0.05). Although the vascularity index obtained by SMI did not exhibit a statistically significant change across different BTXA concentrations, this technique effectively illustrated the microvascular perfusion in HS. Immunohistochemical staining for CD31 revealed that BTXA inhibited angiogenesis.
UNASSIGNED: HFUS and SWE displayed excellent performance in evaluating HS thickness and stiffness. SMI showed a good performance in reflecting microvascular signals in HS. These ultrasound techniques have great potential in assessing the therapeutic effect of BTXA in HS.

Background/Objectives: The utility of shear wave elastography (SWE) as an adjunct to ultrasound biometry and Doppler velocimetry for the examination of placental dysfunction and suboptimal fetal growth is unclear. To date, limited data exist correlating the mechanical properties of placentae with fetal growth. This study aimed to investigate the relationship between placental shear wave velocity (SWV) and ultrasound estimated fetal weight (EFW), and to ascertain if placental SWV is a suitable proxy measure of placental function in the surveillance of small-for-gestational-age (SGA) pregnancies. Methods: This prospective, observational cohort study compared the difference in placental SWV between SGA and appropriate-for-gestational-age (AGA) pregnancies. There were 221 women with singleton pregnancies in the study cohort-136 (61.5%) AGA and 85 (38.5%) SGA. Fetal biometry, Doppler velocimetry, the deepest vertical pocket of amniotic fluid, and mean SWV were measured at 2-4-weekly intervals from recruitment to birth. Results: There was no difference in mean placental SWV in SGA pregnancies compared to AGA pregnancies, nor was there any relationship to EFW. Conclusions: Although other studies have shown some correlation between increased placental stiffness and SGA pregnancies, our investigation did not support this. The mechanical properties of placental tissue in SGA pregnancies do not result in placental SWVs that are apparently different from those of AGA controls. As this study did not differentiate between constitutionally or pathologically small fetuses, further studies in growth-restricted cohorts would be of benefit.

BACKGROUND: Fibrosis is a common final pathway leading to end-stage renal failure. As the renal medulla and cortex contain different nephron segments, we analyzed the factors associated with the progression of renal medullary and cortical fibrosis.
METHODS: A total of 120 patients who underwent renal biopsy at Kawashima Hospital between May 2019 and October 2022 were enrolled in this retrospective study. Renal medullary and cortical fibrosis and stiffness were evaluated using Masson\'s trichrome staining and shear wave elastography, respectively. Maximum urine osmolality in the Fishberg concentration test was also examined.
RESULTS: Medullary fibrosis was positively correlated with cortical fibrosis (p < 0.0001) and log-converted urinary β2-microglobulin (MG) (log urinary β2-MG) (p = 0.022) and negatively correlated with estimated glomerular filtration rate (eGFR) (p = 0.0002). Cortical fibrosis also correlated with log urinary β2-MG, eGFR, and maximum urine osmolality. Multivariate analysis revealed that cortical fibrosis levels (odds ratio [OR]: 1.063) and medullary stiffness (OR: 1.089) were significantly associated with medullar fibrosis (≧45%). The severe fibrosis group with both medullary fibrosis (≧45%) and cortical fibrosis (≧25%) had lower eGFR and maximum urine osmolality values and higher urinary β2-MG levels than the other groups.
CONCLUSIONS: Patients with disorders involving both renal medullary and cortical fibrosis had decreased maximum urine osmolality but had no abnormalities in the urinary concentrating capacities with either condition. Renal medullary and cortical fibrosis were positively correlated with urinary β2-MG, but not with urinary N-acetyl-beta-D-glucosaminidase.

Histotripsy is a noninvasive focused ultrasound therapy that mechanically fractionates tissue to create well-defined lesions. In a previous clinical pilot trial to treat benign prostatic hyperplasia (BPH), histotripsy did not result in consistent objective improvements in symptoms, potentially because of the fibrotic and mechanically tough nature of this tissue. In this study, we aimed to identify the dosage required to homogenize BPH tissue by different histotripsy modalities, including boiling histotripsy (BH) and cavitation histotripsy (CH). A method for histotripsy lesion quantification via entropy (HLQE) analysis was developed and utilized to quantify lesion area of the respective treatments. These data were correlated to changes in mechanical stiffness measured by ultrasound shear-wave elastography before and after treatment with each parameter set and dose. Time points corresponding to histologically observed complete lesions were qualitatively evaluated and quantitatively measured. For the BH treatment, complete lesions occurred with >=30s treatment time, with a corresponding maximum reduction in stiffness of -90.9±7.2(s.d.)%. High pulse repetition frequency (PRF) CH achieved a similar reduction to that of BH at 288s (-91.6±6.0(s.d.)%), and low-PRF CH achieved a (-82.1±5.1(s.d.)%) reduction in stiffness at dose >=144s. Receiver operating characteristic curve analysis showed that a >~75% reduction in stiffness positively correlated with complete lesions observed histologically, and can provide an alternative metric to track treatment progression.

OBJECTIVE: To investigate early structural and mechanical predictors of plantarflexor muscle strength and the magnitude of Achilles tendon (AT) nonuniform displacement at 6 and 12 months after AT rupture.
METHODS: Thirty-five participants (28 males and 7 females; mean ± SD age 41.7 ± 11.1 years) were assessed for isometric plantarflexion maximal voluntary contraction (MVC) and AT nonuniformity at 6 and 12 months after rupture. Structural and mechanical AT and plantarflexor muscle properties were measured at 2 months. Limb asymmetry index (LSI) was calculated for all variables. Multiple linear regression was used with the 6 and 12 month MVC LSI and 12 month AT nonuniformity LSI as dependent variables and AT and plantarflexor muscle properties at 2 months as independent variables. The level of pre- and post-injury sports participation was inquired using Tegner score at 2 and 12 months (scale 0-10, 10 = best possible score). Subjective perception of recovery was assessed with Achilles tendon total rupture score (ATRS) at 12 months (scale 0-100, 100=best possible score).
RESULTS: Achilles tendon resting angle (ATRA) symmetry at 2 months predicted MVC symmetry at 6 and 12 months after rupture (β = 2.530, 95% CI 1.041-4.018, adjusted R2 = 0.416, p = 0.002; β = 1.659, 95% CI 0.330-2.988, adjusted R2 = 0.418, p = 0.016, respectively). At 12 months, participants had recovered their pre-injury level of sports participation (Tegner 6 ± 2 points). The median (IQR) ATRS score was 92 (7) points at 12 months.
CONCLUSIONS: Greater asymmetry of ATRA in the early recovery phase may be a predictor of plantarflexor muscle strength deficits up to 1 year after rupture.
BACKGROUND: This research is a part of \"nonoperative treatment of Achilles tendon rupture in Central Finland: a prospective cohort study\" that has been registered in ClinicalTrials.gov (NCT03704532).

OBJECTIVE: In correlation with magnetic resonance imaging (MRI), this study attempts to assess the effectiveness of the diagnostic of ultrasonography (US) features and shear wave elastography (SWE) in determining the different causes of heel pain.
METHODS: 55 heels with a mean age of 38.33 ± 10.8 were included in the study (10 control cases and 41 cases, 4 of which had bilateral heel pain). There were 23 female cases (56.1%) and 18 male cases (43.95%). Examinations using shear wave elastography (SWE) and ultrasound (US) were done in different positions. MRI and the obtained data were correlated.
RESULTS: When used to diagnose different heel pain causes, ultrasound demonstrated great sensitivity and specificity. SWE demonstrated a good correlation with MRI findings and enhanced the ultrasound\'s diagnostic precision in identifying plantar fasciitis early on (increased accuracy from 88.9 to 93.33% with 100% sensitivity and 83.3% specificity) and Achilles tendinopathy (increased accuracy from 88.9 to 97.8 with 94.7% sensitivity and 100% specificity).
CONCLUSIONS: In summary, we concluded that heel pain can be efficiently examined by both ultrasound (US) and shear wave elastography (SWE) with the former being used as the primary effective tool and the latter being done to increase diagnostic accuracy. We also concluded that SWE improved the ultrasound\'s diagnostic precision in identifying patients with early plantar fasciitis and Achilles tendinopathy and showed a robust relationship with clinical outcomes, enhancing patient evaluation and follow-up.