Alterations in the mechanical properties or "hardness" of tissues allow physicians to detect disease by palpation. Recently, attempts have been made to quantitate and image these tissue properties with the use of magnetic resonance elastography (MRE). This technique has been validated in ex vivo specimens, including kidney, breast, and prostate. In this study, in vivo MRE imaging of rat renal cortex is demonstrated and validated with a disease model that will facilitate further studies. Normal rats and rats with nephrocalcinosis induced with either 2 or 4 weeks of ethylene glycol exposure were studied with MRE. Histology in the diseased rats documented the presence of nephrocalcinosis. MRE measurements and images of shear stiffness were highly reproducible in individual rats. The shear stiffness of the renal cortex in normal rats was 3.87 kPa (95% CI 2.84 -4.90 kPa). The shear stiffness increased to 5.02 kPa (95% CI 3.34 -6.70 kPa) after 2 weeks of exposure, and to 6.49 kPa (95% CI 4.84 -8.14 kPa) after 4 weeks of exposure (P ‫؍‬ 0.0302, ␣ < 0.05

Introduction The emergence of COVID-19 and its ensuing restrictions on in-person healthcare has resulted in a sudden shift towards the utilization of telemedicine. The purpose of this study is to assess patient satisfaction and patient-reported outcome measures (PROMs) for individuals who underwent follow-up for shoulder surgery using telemedicine compared to those who received traditional in-person clinic follow-up. Methods Patients who underwent either rotator cuff repair or total shoulder arthroplasty during a designated pre-COVID-19 (traditional clinic follow-up) or peri-COVID-19 (telemedicine follow-up) span of time were identified. PROMs including the American Shoulder and Elbow Surgeons standardized assessment form, the three-level version of the EQ-5D form, the 12-Item Short Form survey, and a modified version of a published telemedicine survey were administered to participants six months post-operatively via phone call. Results Sixty patients agreed to participate. There was no significant difference between the pre-COVID-19 and peri-COVID-19 groups in patient satisfaction with their follow-up visit ( p = 0.289), nor was there a significant difference in PROMs between the two groups. In total, 83.33% of the telemedicine group and 70.37% of the in-person clinic group preferred traditional in-person follow-up over telemedicine. Discussion In a cohort of patients who underwent telemedicine follow-up for shoulder surgery during the COVID-19 pandemic, there was no difference in patient satisfaction and PROMs compared to traditional in-person clinic follow-up. This study indicates that while the majority of participants preferred face-to-face visits, patients were relatively satisfied with their care and had similar functional outcome scores in both groups, despite the large disruption in healthcare logistics caused by COVID-19.

Although linked to several vitreoretinal pathologies including traumatic retinal tears, breaks, and symptomatic vitreomacular traction, the dynamic material behavior of the vitreous body in response to mechanical loads is not well understood. The purpose of this study was to evaluate spatiotemporal patterns of collagen fiber reorganization and vitreous deformation (strain) in response to tensile and compressive forces. Using thick slabs of bovine eyes we examined collagen fiber reorganization following tensile and compressive step-loading with quantitative polarized light imaging. Strains were measured from sparse marker arrays and temporal collagen behavior was estimated from creep compliance rheological tests. Results showed that under applied loads (1) collagen fibers became significantly more aligned at the vitreous base (near the pars plana and the ciliary body), (2) vitreous located directly behind the lens deformed significantly more than surrounding regions, and (3) changes in collagen fiber alignment occurred on a short (<5 s) timescale. Together these results show that, despite a homogeneous visual appearance, the vitreous body exhibits anisotropic material behavior in tension and compression. Spatiotemporal patterns of collagen rearrangement were consistent with epidemiological patterns of traumatic retinal damage and vitreoretinal topology. High strains in the vitreous corresponded with locations of lower collagen content that are prone to age-related degeneration. These data suggest that differential fiber alignment and mechanical deformation could contribute to the pathogenesis of these diseases. Computational models that incorporate these experimental data will help improve our understanding of the biomechanical mechanisms that contribute to the pathogenesis of traumatic retinal damage, vitreous degeneration, and vitreoretinal disease.

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