Ultrasound Transient Shear Wave Elasticity Imaging for Tendon Tissue

Degeneration of tendon tissue is a common cause of tendon dysfunction with the symptoms of repeated episodes of pain and palpable increase of tendon thickness. Tendon mechanical properties are directly related to its physiological composition and the structural organization of the interior collagen fibers which could be altered by tendon degeneration due to overuse or injury. Thus, measuring mechanical properties of tendon tissue may represent a quantitative measurement of pain, reduced function, and tissue health. Ultrasound elasticity imaging has been developed in the last two decades and has proved to be a promising tool for tissue elasticity imaging. To date, however, well established protocols of tendinopathy elasticity imaging for diagnosing tendon degeneration in early stages or late stages do not exist. This thesis describes the re-creation of one dynamic ultrasound elasticity imaging method and the development of an ultrasound transient shear wave elasticity imaging platform for tendon and other musculoskeletal tissue imaging. An experimental mechanical stage with proper supporting systems and accurate translating stages was designed and made. A variety of high-quality tissue-mimicking phantoms were made to simulate homogeneous and heterogeneous soft tissues as well as tendon tissues. A series of data acquisition and data processing programs were developed to collect the displacement data from the phantom and calculate the shear modulus and Young’s modulus of the target. The imaging platform was found to be capable of conducting comparative measurements of the elastic parameters of the phantoms and quantitatively mapping elasticity onto ultrasound B-Mode images. This suggests the system has great potential for not only benefiting individuals with tendinopathy with an earlier detection, intervention and better rehabilitation, but also for providing a medical tool for quantification of musculoskeletal tissue dysfunction in other regions of the body such as the shoulder, elbow and knee.

THE INFLUENCE OF CHILDHOOD ABUSE ON LONGITUDINAL COURSE OF RECOVERY IN PSYCHIATRIC REHABILITATION

Background: Empirical outcome studies have identified specific symptomatic, cognitive, emotional and functional sequelae of childhood abuse in people with severe mental illness (SMI). These findings illuminate the need for an integrated understanding of biological, psychological, environmental, and developmental aspects of SMI. Purpose: The purpose of the present study includes the following: 1) to examine reliability and validity of the comprehensive child abuse rating system in a sample of individuals with SMI, 2) to examine the influence of childhood abuse severity on recovery of psychotic symptoms, neurocognition and social-cognition, and social functioning in people with SMI during 12 months of inpatient psychiatric rehabilitation, and 3) to examine moderating effects of social cognition on the relationship between severity of different types of child abuse history and social functioning. Results: In Study I (N=171), the child abuse rating system produced reliable ratings and some subtypes of child abuse history were related to poorer premorbid functioning and cognition, higher overall psychiatric symptoms, and lower social functioning. In Study II (N=161), the longitudinal factor pattern invariance of the measures of social functioning, externality, and psychiatric symptoms were confirmed across 3 time points (e.g., at admission, at 6 months, and at 12 months). In addition, significant but varied linear relationships between subtypes of child abuse and each level of assessment of functioning were identified. In Study III (N=143), the results showed that higher baseline social inference, independent of history of child physical abuse (CPA), played a protective role in improvements in social functioning. High externality appeared to be counter-therapeutic for individuals with no history of CPA but protective for individuals with a more severe history of CPA. Conclusion: The child abuse rating system appears to provide reliable and valid assessment of subtypes of child abuse history of individuals with SMI. Considering the extreme heterogeneity in both SMI and child maltreatment, the current finding sheds light on providing individualized treatment and assessment planning for individuals with SMI and a history of childhood abuse.