MRI texture analysis predicts p53 status in head and neck squamous cell carcinoma.

BACKGROUND AND PURPOSE: Head and neck cancer is common, and understanding the prognosis is an important part of patient management. In addition to the Tumor, Node, Metastasis staging system, tumor biomarkers are becoming more useful in understanding prognosis and directing treatment. We assessed whether MR imaging texture analysis would correctly classify oropharyngeal squamous cell carcinoma according to p53 status. MATERIALS AND METHODS: A cohort of 16 patients with oropharyngeal squamous cell carcinoma was prospectively evaluated by using standard clinical, histopathologic, and imaging techniques. Tumors were stained for p53 and scored by an anatomic pathologist. Regions of interest on MR imaging were selected by a neuroradiologist and then analyzed by using our 2D fast time-frequency transform tool. The quantified textures were assessed by using the subset-size forward-selection algorithm in the Waikato Environment for Knowledge Analysis. Features found to be significant were used to create a statistical model to predict p53 status. The model was tested by using a Bayesian network classifier with 10-fold stratified cross-validation. RESULTS: Feature selection identified 7 significant texture variables that were used in a predictive model. The resulting model predicted p53 status with 81.3% accuracy (P < .05). Cross-validation showed a moderate level of agreement (κ = 0.625). CONCLUSIONS: This study shows that MR imaging texture analysis correctly predicts p53 status in oropharyngeal squamous cell carcinoma with ∼80% accuracy. As our knowledge of and dependence on tumor biomarkers expand, MR imaging texture analysis warrants further study in oropharyngeal squamous cell carcinoma and other head and neck tumors.

A continuous pure moment loading apparatus for biomechanical testing of multi-segment spine specimens.

An apparatus is described that enables the application of continuous pure moment loads to multi-segment spine specimens. This loading apparatus allows continuous cycling of the spine between specified flexion and extension (or right and left lateral bending) maximum load endpoints. Using a six-degree-of-freedom load cell and three-dimensional optoelectronic stereophotogrammetry, characteristic displacement versus load hysteresis curves can be generated and analyzed for different spinal constructs of interest. Unlike quasi-static loading, the use of continuous loading permits the analysis of the spine's behaviour within the neutral zone. This information is of particular clinical significance given that the instability of a spinal segment is related to its flexibility within the neutral zone. Representative curves for the porcine lumbar spine in flexion-extension and lateral bending are presented to illustrate the capabilities of this system.

Evaluating a new mobility device: feedback from women with disabilities in India.

PURPOSE: To gather the opinions of potential wheeled mobility device users at an early stage in the design process to ensure the development of technology which would meet their functional needs. METHOD: Eight women with bilateral lower extremity disabilities living in Gujarat state, India, participated in this study. The women were introduced to a working model of a new wheeled ground mobility device (GADI2) for a brief trial and participated in a feedback interview which solicited information on different aspects of the design, specifically the interface between the device and the user, the physical environment and the sociocultural environment. Both qualitative and quantitative data were collected and analysed. RESULT: Although the overall response to the device was positive, there was a lack of consensus in some of the feedback gathered. There were varying opinions across the participants and recommendations were often in opposition to what would typically be recommended in a traditional rehabilitation setting. CONCLUSIONS: This study investigates and discusses the research findings from a rehabilitation perspective with a focus on the functional versus technical design aspects. The importance of involving potential consumers in the design of technology is highlighted. The small sample size and lack of consensus in some of the results indicates the need for further research and field testing of this new mobility device design.

In vitro flexibility of an experimental pedicle screw and plate instrumentation system on the porcine lumbar spine.

The positive correlation between spinal construct stiffness and fusion rate has led to the use of increasingly rigid surgical spinal instrumentation systems. Unfortunately, however, these rigid systems have also been correlated with sub-optimal fusion quality measures. To date, in vivo studies to explore these relationships have involved the use of different implants and surgical procedures to influence the biomechanical environment at the fusion site. In order to avoid these confounding variables, a novel experimental instrumentation system has been developed which is capable of independently controlling spinal construct flexibility (inverse of stiffness). In the present study, this experimental pedicle screw and plate system was subjected to rigorous pure moment flexibility testing in flexion-extension and lateral bending using an in vitro porcine lumbar spine model. Analysis of the data showed that the system provided a reproducible, stepwise-modulated spinal construct flexibility as measured by neutral zone flexibility, laxity angle and range of motion parameters. Differences in flexibility were most evident using the neutral zone parameters (neutral zone flexibility and laxity angle). This is of particular interest given that the clinical instability of a spinal segment may be related to its behaviour within the neutral zone. This information will ultimately guide the design of improved human spinal instrumentation systems.

Designing appropriate rehabilitation technology: a mobility device for women with ambulatory disabilities in India.

Mobility is an essential requirement for personal independence and social participation. For persons with an ambulatory disability, a lack of mobility creates barriers to the realization of these goals. In developed countries, significant research and development has resulted in the technological advancement of assistive devices. Unfortunately, transfer of these technologies to developing countries has proven difficult. Consequently, effort has been directed at designing appropriate technology in these countries--most often in the form of wheelchairs and hand-driven tricycles. For activities within and around the home, however, especially in cultures where many activities are traditionally performed on the floor, wheelchairs and tricycles are often inappropriate solutions. In response to this, a novel mobility device has been designed for use by women with ambulatory disabilities living in rural and low-income areas of India. The device is intended to assist the user in performing activities of daily living which occur within and near the home, and at ground level. To this end, the device conceptually differs from traditional wheelchair designs in that it physically keeps the rider near to the floor. This paper describes the new device as well as the cross-cultural and cross-professional collaborative methodology used in its design.

A severe adverse reaction to mefloquine and chloroquine prophylaxis.

A 23 year old man with no history of neurological or psychiatric illness ingested three weekly 228 mg doses of mefloquine base (250 mg salt) as malaria prophylaxis while in India. He experienced an increasingly severe adverse reaction after each dose, including symptoms of paranoia, hallucinations, and suicidal ideation. The man discontinued mefloquine and continued malaria prophylaxis with chloroquine. Shortly after the first 300 mg dose of chloroquine base (500 mg chloroquine phosphate salt), symptoms acutely intensified and became debilitating. Severe symptoms persisted for 12 months following the discontinuation of both antimalarial drugs.