Magnetic resonance elastography with guided pressure waves

Magnetic resonance elastography aims to non-invasively and remotely characterize the mechanical properties of living tissues. To quantitatively and regionally map the shear viscoelastic moduli in vivo, the technique must achieve proper mechanical excitation throughout the targeted tissues. Although it is straightforward, ante manibus, in close organs such as the liver or the breast, which practitioners clinically palpate already, it is somewhat fortunately highly challenging to trick the natural protective barriers of remote organs such as the brain. So far, mechanical waves have been induced in the latter by shaking the surrounding cranial bones. Here, the skull was circumvented by guiding pressure waves inside the subject's buccal cavity so mechanical waves could propagate from within through the brainstem up to the brain. Repeatable, reproducible and robust displacement fields were recorded in phantoms and in vivo by magnetic resonance elastography with guided pressure waves such that quantitative mechanical outcomes were extracted in the human brain.     

Impaired self-awareness after traumatic brain injury: a systematic review. Part 1: Assessment,clinical aspects and recovery

BackgroundImpaired self-awareness (ISA) has frequently been found to be both frequent and deleterious in patients with moderate to severe traumatic brain injury (TBI).ObjectivesThe present paper is the first of a two-part systematic review of ISA after traumatic brain injury (TBI), focusing on assessment methods, clinical aspects and recovery.MethodsFollowing the PRISMA guidelines, 95 articles meeting the inclusion criteria were included.ResultsISA occurs in 30% to 50% of patients with moderate to severe TBI, although it tends to improve with time. There is no one single gold-standard measure of ISA. Self-proxy discrepancy scores, with scales such as the Patient Competency Rating Scale or the Awareness Questionnaire, or a structured interview such as the Self Awareness of Deficits Interview, are the most frequently used assessment methods, with adequate psychometric properties. Scores on these different scales correlate only moderately with each other, which suggests that they may address different aspects of self-awareness. ISA mainly concerns cognitive and behavioral problems rather than physical or sensory impairments and may concern different areas of functioning, such as anticipatory, emergent or meta-cognitive awareness.ConclusionISA is a complex and multifaceted issue that should be systematically assessed in rehabilitation settings using a range of relatively well-validated tools. The consequences and predictors of ISA after TBI will be addressed in a companion paper.     

Etiologic Classification Criteria of ARCO on Femoral Head Osteonecrosis Part 2: Alcohol-Associated Osteonecrosis

Background

Although alcohol is a leading risk factor for osteonecrosis of the femoral head (ONFH) and its prevalence reportedly ranges from 20% to 45%, there are no unified classification criteria for this subpopulation. In 2015, Association Research Circulation Osseous decided to develop classification criteria for alcohol-associated ONFH.