Journal of engineering and science in medical diagnostics and therapy最新文献

Investigating the dynamic response of human tympanic membranes (TMs) exposed to blasts requires full-field-of-view and three-dimensional (3D) methodologies. Our paper introduces a system that combines high-speed 3D digital image correlation (HS 3D-DIC) and Schlieren imaging (HS-SI) with a custom-designed shock tube for generating blast waves. This integrated system allows us to measure TM surface motions under intense transient loading, capturing full-field-of-view shape deformations exceeding 100 μm with a temporal resolution of 10 μs. System characterization encompasses (i) measuring the shock tube's output levels and repeatability, (ii) assessment of the spatial and temporal resolutions of the imaging techniques, and (iii) identification of overall system limitations. Optimizing these factors is crucial for improving the reliability of our system to ensure the accurate measurement of deformations. To assess our shock tube's reliability in generating repeated blast waves, we instrumented it with high-pressure (HP) and high-frequency (HF) pressure sensors along the blast wave pathway to record overpressure waveforms and compared them with Schlieren imaging visualized blast waves. We validate our HS 3D-DIC measured deformations by comparing them with deformations measured using single-point laser Doppler vibrometry (LDV), establishing a comprehensive assessment of the TM's dynamic response and potential fracture mechanics under blast. Finally, we test our approach with 3D-printed TM-like samples and a real cadaveric human TM. This methodology lays the groundwork for further investigations of blast-related auditory damage and the invention of more effective protective and medical solutions.

Regardless of the way of treatment, persistent deficits in calf muscles in recovered patients from Achilles tendon rupture (ATR) exist long-term postinjury. Studies on calf muscle changes mostly highlight morphological changes in the calf muscles and Achilles tendon. However, limited attention has been given to fascicular changes. Diffusion tensor imaging (DTI) can provide a better understanding of the characteristics and properties of tissues with organized microstructure. In the current study, we used DTI-derived indices (mean diffusivity (MD), fractional anisotropy (FA), and eigenvalues-λ ₁, λ ₂, and λ ₃) and fiber tractography to better understand the soleus muscle after recovery from ATR by comparing the results of injured legs with healthy ones. Our findings suggest that the standard deviations of measured parameters (FA, MD, and eigenvalues) within the soleus muscle are better predictors of the changes associated with the ATR as compared to the control counterpart for the volumetric region of interest (ROI). Additionally, in four out of five participants, smaller tracts were observed in the injured leg compared to the healthy one, as evidenced by the fiber length distribution of the tracts. Altogether, this study demonstrates the feasibility of the DTI and fiber tractography approaches to quantify the fascicular changes in the individuals recovered from ATR.

Following the diagnosis of unilateral cervical radiculopathy and need for surgical intervention, anterior cervical diskectomy and fusion (conventional fusion) and posterior cervical foraminotomy are common options. Although patient outcomes may be similar between the two procedures, their biomechanical effects have not been fully compared using a head-to-head approach, particularly, in relation to the amount of facet resection and internal load-sharing between spinal segments and components. The objective of this investigation was to compare load-sharing between conventional fusion and graded foraminotomy facet resections under physiological loading. A validated finite element model of the cervical spinal column was used in the study. The intact spine was modified to simulate the two procedures at the C5-C6 spinal segment. Flexion, extension, and lateral bending loads were applied to the intact, graded foraminotomy, and conventional fusion spines. Load-sharing was determined using range of motion data at the C5-C6 and immediate adjacent segments, facet loads at the three segments, and disk pressures at the adjacent segments. Results were normalized with respect to the intact spine to compare surgical options. Conventional fusion leads to increased motion, pressure, and facet loads at adjacent segments. Foraminotomy leads to increased motion and anterior loading at the index level, and motions decrease at adjacent levels. In extension, the left facet load decreases after foraminotomy. Recognizing that foraminotomy is a motion preserving alternative to conventional fusion, this study highlights various intrinsic biomechanical factors and potential instability issues with more than one-half facet resection.