University of Southern California
University of Southern California
Mrs. T.H. Chan Division of Occupational Science and Occupational Therapy
Mrs. T.H. Chan Division of Occupational Science and Occupational Therapy
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Shawn C. Roll PhD, OTR/L, RMSKS, FAOTA

Shawn Roll

Director of the PhD in Occupational Science Program and Associate Professor

Room: HRA 505
(323) 442-1850
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Shawn C. Roll received his B.S. in Occupational Therapy from The Ohio State University, graduating magna cum laude with distinction. He continued his post-secondary education at OSU, obtaining an M.S. in Allied Health Professions with a Minor in Research Methods in Human Resources Development, and received his Ph.D. degree in Health and Rehabilitation Sciences with an Interdisciplinary Specialization in College and University Teaching. Dr. Roll's clinical experience is in work programs, focusing on assessment, prevention and rehabilitation of work-related injuries. Dr. Roll is a registered and licensed occupational therapist (OTR/L) and a registered musculoskeletal sonographer (RMSKS). He was named a Fellow of the American Occupational Therapy Association in 2015.

Research Interests

Dr. Roll has developed an interdisciplinary research career combining his clinical occupational therapy skills with specialization in musculoskeletal sonography and industrial engineering/ergonomics. Through his research, he collaborates with rehabilitation providers, radiologic sciences, industrial and systems engineering, neurology and orthopedics. Dr. Roll's research strives to advance the understanding of musculoskeletal disorders through a holistic approach, to effectively evaluate and provide prevention or rehabilitation interventions within the adult population. His research focus includes:

  • Use of diagnostic sonography in the evaluation, prevention and treatment of musculoskeletal disorders with a primary focus on the upper extremities
  • Investigation of physical exposures, stress, psychosocial factors and personality traits as each relate to the development of musculoskeletal disorders and how each mitigate or promote successful prevention and rehabilitation efforts
  • Investigation of tools and approaches for determining functional capacity in healthy and injured workers


PhD in Health & Rehabiliation Sciences
2011 | The Ohio State University

Master of Science (MS) in Allied Health Professions
2006 | The Ohio State University

Bachelor of Science (BS) in Allied Health Professions (Occupational Therapy)
2002 | The Ohio State University



Hegmann, K. T., Melhorn, J. M., Ausfahl, J., Freshwater, M. F., Prezzia, C. P., Rempel, D. M., Roll, S. C., Rollins, R. J., Werner, R. A., & Zaremski, J. (2016). ACOEM hand, wrist, and forearm disorders guideline. Westminster, CO: Reed Group. Full text

Roll, S. C. (2015). Carpal tunnel syndrome: Improving intervention effectiveness. Brockton, MA: Specialty Commerce Publishing. Full text

Journal Articles

Dhyani, M., Roll, S. C., Gilbertson, M. W., Orlowski, M., Anvari, A., Li, Q., Anthony, B., & Samir, A. E. (2017). Direct and precise quantification of forces applied by sonographers during abdominal imaging. Work, 52, 241-247. Show abstractHide abstract

BACKGROUND: There is a significantly high rate of work-related musculsokeletal injuries in sonography professionals. To date, assessment of risk factors for work- related injuries in sonographers has been based primarily on surveys, subjective reports, and observational methods. There is a need to develop quantitative techniques to better understand risk factors and develop preventive interventions.
OBJECTIVE: We pilot tested a high-resolution force-measuring probe capable of precisely measuring forces applied through the transducer by sonographers and used this novel direct measurement technique to evaluate forces during abdominal imaging.
METHODS: Twelve sonographers with varied experience, ranging from 1-33 years, performed routine abdominal scans on 10 healthy volunteers who had varied body mass indices (BMI). Imaging was conducted using the force-measuring probe, which provided real-time measurement of forces, and angles. Data were compared by sonographer years of experience and subject BMI.
RESULTS: In total, 47 abdominal examinations were performed as part of this study, and all images met standards for clinical diagnostic quality. The mean contact force applied across all exams was 8.2±4.3 Newtons (N) (range: 1.2-36.5N). For subjects in the high BMI group (BMI>25, n=4) the mean force was 10.5N (range: 8.9-13.2N) compared to 7.9N (range: 5.9-10.9N) for subjects with normal BMI (BMI=18.5-25, n=6). Similarly, the mean maximum force applied for subjects with high BMI (25.3N) was significantly higher than force applied for subjects with normal BMI (17.4N). No significant difference was noted in the amount of force applied by sonographers with more than 5 years of experience (n=6) at 8.2N (Range: 5.1-10.0N) compared to less experienced sonographers (n=6), whose forces averaged 8.1N (Range: 5.8-10.0N).
CONCLUSIONS: It is feasible to directly measure forces applied by sonographers using a high-resolution force measurement system. Forces applied during abdominal imaging vary widely, are significantly higher when scanning subjects with high BMI, and are not related to sonographer years of experience. This force measurement system has the potential to provide an additional quantitative data point to explore the impact of applied forces on sonographer related musculoskeletal injury, particularly in conjunction with various body positions, exam types and force durations.

Takata, S. C., Wade, E. T., & Roll, S. C. (2017). Hand therapy interventions, outcomes, and diagnoses evaluated over the last 10 years: A mapping review linking research to practice. Journal of Hand Therapy. Advance online publication. Show abstractHide abstract

STUDY DESIGN: Mapping review.
INTRODUCTION: Although published literature and evidence to support medical practice is becoming more abundant, it is not known how well available evidence supports the full spectrum of hand therapy practice.
PURPOSE OF THE STUDY: The aim of this mapping review was to identify strengths and/or gaps in the available literature as compared with the hand therapy scope of practice to guide future research.
METHODS: A systematic search and screening was conducted to identify evidence published from 2006 to 2015. Descriptive data from 191 studies were extracted, and the diagnoses, interventions, and outcomes used in the literature were compared with the hand therapy scope of practice.
RESULTS: Osteoarthritis, tendon surgeries, and carpal tunnel syndrome were most frequently studied. Exercise, education, and orthotic interventions were most common, each used in more than 100 studies; only 12 studies used activity-based interventions. Primary outcome measures included range of motion, pain/symptoms, strength, and functional status.
DISCUSSION: Abundant high-quality research exists for a portion of the hand therapy scope of practice; however, there is a paucity of evidence for numerous diagnoses and interventions.
CONCLUSIONS: More evidence is needed for complex diagnoses and activity-based interventions as well as behavioral and quality-of-care outcomes.
LEVEL OF EVIDENCE: Not applicable.

Roll, S. C. (2017). Embracing the expanding horizons of diagnostic medical sonography: Clinical innovation, interdisciplinary growth, and scientific discovery. Journal of Diagnostic Medical Sonography, 33, 81-82.

Roll, S. C. (2017). Current evidence and opportunities for expanding the role of occupational therapy for adults with musculoskeletal conditions. American Journal of Occupational Therapy, 71, 7101170010p1-7101170010p5. Show abstractHide abstract

Musculoskeletal conditions are the second greatest cause of disability worldwide, and chronic musculoskeletal conditions affect nearly the same percentage of the general population as chronic circulatory and respiratory conditions combined. Moreover, people with musculoskeletal conditions experience a significant decline in independence with daily activities and occupational performance, key areas targeted by occupational therapy interventions. This special issue of the American Journal of Occupational Therapy provides comprehensive summaries of evidence for the care of common musculoskeletal conditions, highlights important implications that support evidence-informed practice, and proposes ways to advance the practice of occupational therapy to improve the lives of people with musculoskeletal conditions.

Roll, S. C., & Hardison, M. E. (2017). Effectiveness of occupational therapy interventions for adults with musculoskeletal conditions of the forearm, wrist, and hand: A systematic review. American Journal of Occupational Therapy, 71, 7101180010p1-7101180010p12. Show abstractHide abstract

Occupational therapy practitioners are key health care providers for people with musculoskeletal disorders of the distal upper extremity. It is imperative that practitioners understand the most effective and efficient means for remediating impairments and supporting clients in progressing to independence in purposeful occupations. This systematic review provides an update to a previous review by summarizing articles published between 2006 and July 2014 related to the focused question, What is the evidence for the effect of occupational therapy interventions on functional outcomes for adults with musculoskeletal disorders of the forearm, wrist, and hand? A total of 59 articles were reviewed. Evidence for interventions was synthesized by condition within bone, joint, and general hand disorders; peripheral nerve disorders; and tendon disorders. The strongest evidence supports postsurgical early active motion protocols and splinting for various conditions. Very few studies have examined occupation-based interventions. Implications for occupational therapy practice and research are provided.

Marik, T. L., & Roll, S. C. (2017). Effectiveness of occupational therapy interventions for musculoskeletal shoulder conditions: A systematic review. American Journal of Occupational Therapy, 71, 7101180020p1-7101180020p11. Show abstractHide abstract

People with musculoskeletal disorders of the shoulder commonly experience pain, decreased strength, and restricted range of motion (ROM) that limit participation in meaningful occupational activities. The purpose of this systematic review was to evaluate the current evidence for interventions within the occupational therapy scope of practice that address pain reduction and increase participation in functional activities. Seventy-six studies were reviewed for this study-67 of Level I evidence, 7 of Level II evidence, and 2 of Level III evidence. Strong evidence was found that ROM, strengthening exercises, and joint mobilizations can improve function and decrease pain. The evidence to support physical modalities is moderate to mixed, depending on the shoulder disorder. Occupational therapy practitioners can use this evidence to guide daily clinical decision making.

Hardison, M. E., & Roll, S. C. (2017). Factors associated with success in an occupational rehabilitation program for work-related musculoskeletal disorders. American Journal of Occupational Therapy, 71, 7101190040p1-7101190040p8. Show abstractHide abstract

Work-related musculoskeletal disorders are a significant burden; however, no consensus has been reached on how to maximize occupational rehabilitation programs for people with these disorders, and the impact of simulating work tasks as a mode of intervention has not been well examined. In this retrospective cohort study, the authors used logistic regression to identify client and program factors predicting success for 95 clients in a general occupational rehabilitation program and 71 clients in a comprehensive occupational rehabilitation program. The final predictive model for general rehabilitation included gender, number of sessions completed, and performance of work simulation activities. Maximum hours per session was the only significant predictor of success in the comprehensive rehabilitation program. This study identifies new factors associated with success in occupational rehabilitation, specifically highlighting the importance of intensity (i.e., session length and number of sessions) of therapy and occupation-based activities for this population.

Gray, J. M., Frank, G., & Roll, S. C. (2017). Integrating musculoskeletal sonography into rehabilitation: Therapists' experiences with training and implementation. OTJR: Occupation, Participation and Health, 37, 40-49. Show abstractHide abstract

Musculoskeletal sonography is rapidly extending beyond radiology; however, best practices for successful integration into new practice contexts are unknown. This study explored non-physician experiences with the processes of training and integration of musculoskeletal sonography into rehabilitation. Qualitative data were captured through multiple sources, and iterative thematic analysis was used to describe two occupational therapists' experiences. The dominant emerging theme was competency, in three domains: technical, procedural, and analytical. In addition, three practice considerations were illuminated: (a) understanding imaging within the dynamics of rehabilitation, (b) navigating nuances of interprofessional care, and (c) implications for post-professional training. Findings indicate that sonography training for rehabilitation providers requires multi-level competency development and consideration of practice complexities. These data lay a foundation on which to explore and develop best practices for incorporating sonographic imaging into the clinic as a means for engaging clients as active participants in the rehabilitation process to improve health and rehabilitation outcomes.

Roll, S. C., Asai, C., & Tsai, J. (2016). Clinical utilization of musculoskeletal sonography involving non-physician rehabilitation providers: A scoping review. European Journal of Physical and Rehabilitation Medicine, 52, 253-262. Full text Show abstractHide abstract

BACKGROUND: Musculoskeletal sonography use in point-of-care physical medicine and rehabilitation is rapidly expanding, not only by physiatrists, but also by non-physician rehabilitation providers.
AIM: To evaluate the current range, extent and nature of literature and to identify emerging areas of evidence for the use of musculoskeletal sonography involving non-physician rehabilitation providers to guide research and clinical practice.
DESIGN: Scoping Review SETTING: Inpatient, Outpatient, Other POPULATION: Musculoskeletal conditions METHODS: Five databases were searched and 578 unique abstracts were identified and screened for eligibility. Three raters independently read 68 full texts and 36 articles that reported on applied uses of sonography by non-physician rehabilitation providers were included.
RESULTS: Eighteen studies described direct clinical use, primarily for outcomes measurement (n=12) or as a biofeedback intervention (n=10). Twelve laboratory studies were included that related morphology to patient reports or validated clinical interventions. Six additional studies, although not involving non-physician providers, were included as they presented potential valuable uses that were not noted in the other included studies, such as monitoring bone healing, tendon repair, and evaluation of idiopathic symptom reports or non-specific primary diagnoses.
CONCLUSION: This review indicates that non-physician rehabilitation providers use sonography for outcomes measurement and biofeedback interventions. Research is needed to evaluate effects of these uses on patient outcomes and to explore additional potential uses for clinical reasoning, treatment planning, and monitoring of tissue healing related to intervention.
CLINICAL REHABILITATION IMPACT: Implementation of musculoskeletal sonography by non-physician rehabilitation providers has the potential to be a critically advantageous addition to improve care.

Hardison, M. E., & Roll, S. C. (2016). Mindfulness interventions in physical rehabilitation: A scoping review. American Journal of Occupational Therapy, 70, 7003290030p1-7003290030p9. Show abstractHide abstract

A scoping review was conducted to describe how mindfulness is used in physical rehabilitation, identify implications for occupational therapy practice, and guide future research on clinical mindfulness interventions. A systematic search of four literature databases produced 1,524 original abstracts, of which 16 articles were included. Although only 3 Level I or II studies were identified, the literature included suggests that mindfulness interventions are helpful for patients with musculoskeletal and chronic pain disorders and demonstrate trends toward outcome improvements for patients with neurocognitive and neuromotor disorders. Only 2 studies included an occupational therapist as the primary mindfulness provider, but all mindfulness interventions in the selected studies fit within the occupational therapy scope of practice according to the American Occupational Therapy Association's Occupational Therapy Practice Framework: Domain and Process. Higher-level research is needed to evaluate the effects of mindfulness interventions in physical rehabilitation and to determine best practices for the use of mindfulness by occupational therapy practitioners.

Roll, S. C., Gray, J. M., Frank, G., & Wolkoff, M. (2015). Exploring occupational therapists' perceptions of the usefulness of musculoskeletal sonography in upper-extremity rehabilitation [Brief report]. American Journal of Occupational Therapy, 69, 6904350020p1-6904350020p6. Show abstractHide abstract

OBJECTIVE: To identify the potential utility of musculoskeletal sonographic imaging in upper-extremity rehabilitation.
METHOD: Two occupational therapists in an outpatient hand rehabilitation clinic were recruited by convenience, were trained in the use of sonography, and implemented sonographic imaging in their clinical practice. Qualitative data were obtained during and after the implementation period by means of questionnaires and interviews. Data collection, analysis, and interpretation were completed in an iterative process that culminated in a thematic analysis of the therapists' perceptions.
RESULTS: The data indicate four potential areas of utility for musculoskeletal sonography in upper-extremity rehabilitation: (1) mastering anatomy and pathology, (2) augmenting clinical reasoning, (3) supplementing intervention, and (4) building evidence.
CONCLUSION: Numerous potential uses were identified that would benefit both therapist and client. Further exploration of complexities and efficacy for increasing patient outcomes is recommended to determine best practices for the use of musculoskeletal sonography in upper-extremity rehabilitation.

Roll, S. C., Volz, K. R., Fahy, C. M., & Evans, K. D. (2015). Carpal tunnel syndrome severity staging using sonographic and clinical measures. Muscle & Nerve, 51, 838-845. Show abstractHide abstract

INTRODUCTION: Ultrasonography may be valuable in staging carpal tunnel syndrome severity, especially by combining multiple measures. This study aimed to develop a preliminary severity staging model using multiple sonographic and clinical measures.
METHODS: Measures were obtained in 104 participants. Multiple categorization structures for each variable were correlated to diagnostic severity based on nerve conduction. Goodness-of-fit was evaluated for models using iterative combinations of highly correlated variables. Using the best-fit model, a preliminary scoring system was developed, and frequency of misclassification was calculated.
RESULTS: The severity staging model with best fit (Rho 0.90) included patient-reported symptoms, functional deficits, provocative testing, nerve cross-sectional area, and nerve longitudinal appearance. An 8-point scoring scale classified severity accurately for 79.8% of participants.
DISCUSSION: This severity staging model is a novel approach to carpal tunnel syndrome evaluation. Including more sensitive measures of nerve vascularity, nerve excursion, or other emerging techniques may refine this preliminary model.

Roll, S. C. (2015). Role of sonographic imaging in occupational therapy practice [In brief]. American Journal of Occupational Therapy, 69, 6903360010p1-6903360010p8. Show abstractHide abstract

Occupational therapy practice is grounded in the delivery of occupation-centered, patient-driven treatments that engage clients in the process of doing to improve health. As emerging technologies, such as medical imaging, find their way into rehabilitation practice, it is imperative that occupational therapy practitioners assess whether and how these tools can be incorporated into treatment regimens that are dually responsive to the medical model of health care and to the profession's foundation in occupation. Most medical imaging modalities have a discrete place in occupation-based intervention as outcome measures or for patient education; however, sonographic imaging has the potential to blend multiple occupational therapy practice forms to document treatment outcomes, inform clinical reasoning, and facilitate improved functional performance when used as an accessory tool in direct intervention. Use of medical imaging is discussed as it relates to occupational foundations and the professional role within the context of providing efficient, effective patient-centered rehabilitative care.

Roll, S. C., Rana, M., Sigward, S. M., Yani, M. S., Kirages, D. J., & Kutch, J. J. (2015). Reliability of superficial male pelvic floor structural measurements using linear-array transperineal sonography. Ultrasound in Medicine & Biology, 41, 610-617. Show abstractHide abstract

This study evaluated reliability of measures for superficial structures of the male pelvic floor (PF) obtained via transperineal sonography. Two embalmed cadavers were dissected to identify positioning of muscles on and around the bulb of the penis and to confirm the PF protocol. Cross-sectional area (CSA) and linear thickness of the bulb of the penis, urethra, bulbospongiosus (BS) muscles, and ischiocavernosus (IC) muscles were measured on 38 transverse images from 20 male patients by three raters with varied study knowledge and sonographic experience. Intra- and inter-rater reliability were calculated with two-way, mixed effects intra-class correlation coefficients. Measures of the bulb of the penis had the best reliability. CSA of all muscles and sagittal thickness of the BS near the central tendon had good reliability. Reliability varied for rater-identified thickest muscle region and measures of the urethra. Our study suggests that structures of the male PF can be reliably evaluated using a transperineal sonographic approach.

Roll, S. C., Selhorst, L., & Evans, K. D. (2014). Contribution of positioning to work-related musculoskeletal discomfort in diagnostic medical sonographers. Work, 47, 253-260. Show abstractHide abstract

BACKGROUND: Musculoskeletal pain and discomfort due to work exposure is experienced by 90% of sonographers. Survey research has provided a wealth of information to document this problem, but few studies have attempted to directly measure and identify the source of these disorders.
OBJECTIVE: This pilot observational study was conducted to obtain direct measures of the relationship of sonographers to their environment during the completion of sonographic examinations.
METHODS: The Rapid Upper Limb Assessment (RULA) was used to evaluate the positions of five sonographers during 24 sonographic examinations. The observed positions were compared among the various examinations and the association of these observed postures to discomfort, sonographer height, and exam table height was evaluated.
RESULTS: All participants reported an increase in musculoskeletal discomfort at the end of the workday. Overall RULA scores ranged from 3.11 to 5.00 with upper extremity venous Doppler and transvaginal pelvic examinations averaging the highest. Increasingly poor upper extremity positioning was positively associated with increased musculoskeletal discomfort (r = 0.53, p <0.01).
CONCLUSIONS: Regardless of the examination being performed, sonographers are working in positions that require further evaluation and intervention. Longitudinal studies are needed that evaluate the inter-relationship of biopsychosocial risk factors of musculoskeletal injuries.

Roll, S. C., Darragh, A. R., O'Brien, J. C., & Fosjer, T. F. (2014). In memoriam: Jane Douglas Case-Smith (September 5, 1953 - July 30, 2014). OTJR: Occupation, Participation and Health, 34, 171-175.

Evans, K. D., Volz, K. R., Pargeon, R. L., Fout, L. T., Buford, J., & Roll, S. C. (2014). Use of contrast enhanced sonography to investigate intraneural vascularity in a cohort of macaca fascicularis with suspected median mononeuropathy. Journal of Ultrasound in Medicine, 33, 103-109. Show abstractHide abstract

OBJECTIVES: The purpose of this study was to provide clinical evidence of the use of contrast-enhanced sonography in detecting and quantifying changes in intraneural vascularity due to median mononeuropathy. METHODS: Five Macaca fascicularis monkeys were exposed to 20 weeks of repetitive work to increase their risk of developing median mononeuropathy. Contrast-enhanced sonograms were obtained in 30-second increments for 7 minutes while a contrast agent was being delivered. Data were collected immediately at the conclusion of the 20-week work exposure and then again during a recovery phase approximately 3 months after the completion of work. Quantitative analysis and trend graphs were used to analyze median nerve perfusion intensity. This study also compared the use of both manual counting of pixels and semiautomatic measurement using specialized software. RESULTS: Based on the average data, maximum intensity values were identified as the best indicators of nerve hyperemia. Paired t tests demonstrated significantly higher maximum intensities in the working stage for 4 of the 5 subjects (P < .01). CONCLUSIONS: This study provides preliminary evidence that (1) in a controlled exposure model, a change in intraneural vascularity of the median nerve between working and recovery can be observed; (2) this vascular change can be measured using an objective technique that quantifies the intensity of vascularity; and (3) contrast-enhanced sonography may improve the ability to reliably capture and measure low-flow microvascularity.

Roll, S. C., Evans, K. D., Volz, K. R., & Sommerich, C. M. (2013). Longitudinal design for sonographic measurement of median nerve swelling with controlled exposure to physical work using an animal model. Ultrasound in Medicine & Biology, 39, 2492-2497. Show abstractHide abstract

In the study described here, we examined the feasibility of a longitudinal design to measure sonographically swelling of the median nerve caused by controlled exposure to a work task and to evaluate the relationship of changes in morphology to diagnostic standards. Fifteen macaques, Macaca fascicularis, pinched a lever in various wrist positions at a self-regulated pace (8 h/d, 5 d/wk, 18–20 wk). Nerve conduction velocity (NCV) and cross sectional area (CSA) were measured every 2 wk from baseline through working and a 6-wk recovery. Trending across all subjects revealed that NCV slowed and CSA at the carpal tunnel increased in the working arm, whereas no changes were observed in CSA either at the forearm or for any measure in the non-working arm. There was a small negative correlation between NCV and CSA in the working arm. This study provides validation that swelling can be observed using a longitudinal design. Longitudinal human studies are needed to describe the trajectory of nerve swelling for early identification of median nerve pathology.

Evans, K. D., Volz, K. R., Roll, S. C., Hutmire, C. M., Pargeon, R. L., Buford, J. A., & Sommerich, C. M. (2013). Establishing an imaging protocol for detection of vascularity within the median nerve using contrast enhanced ultrasound. Journal of Diagnostic Medical Sonography, 29, 201-207. Show abstractHide abstract

This preclinical study was conducted to develop discrete sonographic instrumentation settings and also safe contrast dosing that would consistently demonstrate perineural vascularity along the median nerve. This set of imaging studies was conducted with a convenience cohort of young adult female monkeys (Macaca fascicularis). Sonographic equipment settings and dosing were refined throughout the imaging series to ensure consistent contrast-enhanced ultrasound imaging. A mechanical index of 0.13 was consistently used for imaging. Perineural vessels were imaged with a suspension solution of 0.04 mL Definity/0.96 mL saline introduced over 5 minutes for a total dose of 0.8 mL of contrast solution. Blinded studies of high and low dose contrast, along with saline injections, were correctly identified by two experienced sonographers. This preclinical study established adequate equipment settings and dosing that allowed for a valid demonstration of vascularity surrounding the median nerve.

Evans, K. D., Roll, S. C., Volz, K. R., & Freimer, M. (2013). [Reply] Nerve Blood Flow. Journal of Ultrasound in Medicine, 32, 188-189. Full text

Roll, S. C., & Kutch, J. J. (2013). Transperineal sonography evaluation of muscles and vascularity in the male pelvic floor. Journal of Diagnostic Medical Sonography, 29, 3-10. Show abstractHide abstract

Idiopathic chronic male pelvic pain is difficult to diagnose and treat. Currently, diagnosis relies on subjective symptoms; objective measures of neuromuscular mechanisms have not been investigated. Sonographic imaging has been used to investigate these neuromuscular mechanisms in the female pelvic floor, but neither research nor books describe sonography evaluation of the male pelvic floor. The purpose of this study was to develop and evaluate a perineal sonographic technique for the examination of the male pelvic floor muscles. Anatomic landmarks were identified with images collected from two subjects, one with intermittent reports of pelvic pain and one with no history of pain in the pelvic region. A description of the equipment settings, the examination protocol, and the resulting comparative image analysis is included. A validated protocol such as this may be useful in documenting differences in the soft tissue structures between asymptomatic individuals and patients with chronic pelvic pain to aid in diagnosis and treatment. This is the first known study to report sonographic findings of the individual muscles in the male pelvic floor, and additional research is needed to validate the techniques that have been deemed feasible.

Roll, S. C., Evans, K. D., Li, X., Sommerich, C. M., & Case-Smith, J. (2013). Importance of tissue morphology relative to patient reports of symptoms and functional limitations resulting from median nerve pathology. American Journal of Occupational Therapy, 67, 64-72. Show abstractHide abstract

Significant data exist for the personal, environmental, and occupational risk factors for carpal tunnel syndrome. Few data, however, explain the interrelationship of tissue morphology to these factors among patients with clinical presentation of median nerve pathology. Therefore, our primary objective was to examine the relationship of various risk factors that may be predictive of subjective reports of symptoms or functional deficits accounting for median nerve morphology. Using diagnostic ultrasonography, we observed real-time median nerve morphology among 88 participants with varying reports of symptoms or functional limitations resulting from median nerve pathology. Body mass index, educational level, and nerve morphology were the primary predictive factors. Monitoring median nerve morphology with ultrasonography may provide valuable information for clinicians treating patients with symptoms of median nerve pathology. Sonographic measurements may be a useful clinical tool for improving treatment planning and provision, documenting patient status, or measuring clinical outcomes of prevention and rehabilitation interventions.

Roll, S. C. (2012). Injuries and prevention in health care providers. Work, 42, 309-310.

Roll, S. C., Evans, K. D., Hutmire, C. D., & Baker, J. P. (2012). An analysis of occupational factors related to shoulder discomfort in diagnostic medical sonographers and vascular technologists. Work, 42, 355-365. Show abstractHide abstract

OBJECTIVE: Three-fourths of diagnostic medical sonographers (DMS) and vascular technologists (VT) experiencing discomfort due to job demands indicate having discomfort in the shoulder region. An analysis of factors related to shoulder discomfort highlighted salient factors requiring further investigation and intervention.
METHODS: The responses of 2,163 DMS and VT from a survey of a representative sample were analyzed to determine personal factors, work demands, and workstation design characteristics of those experiencing discomfort in the shoulder region. Frequencies and response distributions were calculated and cross tabulation with chi-square analysis was completed.
RESULTS: A majority of respondents with shoulder discomfort have co-morbid reports of discomfort in other locations. While overall sonographer discomfort is linked to age and years of experience, shoulder discomfort was also noted to be linked to specific workstation characteristics. A lack of adjustability in equipment, PACS workstations, and positions required to complete bedside exams contributes to discomfort due to sustained and repetitive shoulder abduction and twisting of the neck and trunk.
CONCLUSIONS: There is a need for studies investigating redesign of equipment and workstations or interventions with DMS and VT specifically focused on improving adjustability and improved positioning of sonographers in order to reduce shoulder discomfort while performing job demands.

Evans, K. D., Roll, S. C., Volz, K. R., & Freimer, M. (2012). Relationship between intraneural vascular flow measured with sonography and carpal tunnel syndrome diagnosis based on electrodiagnostic testing. Journal of Ultrasound in Medicine, 31, 729-736. Full text Show abstractHide abstract

OBJECTIVES: The purpose of this study was to document and analyze intraneural vascular flow within the median nerve using power and spectral Doppler sonography and to determine the relationship of this vascular flow with diagnosis of carpal tunnel syndrome based on electrodiagnostic testing.
METHODS: Power and spectral Doppler sonograms in the median nerve were prospectively collected in 47 symptomatic and 44 asymptomatic subjects. Doppler studies were conducted with a 12-MHz linear transducer. Strict inclusion criteria were established for postexamination assessment of waveforms; routine quality assurance was completed; electrodiagnostic tests were conducted on the same day as sonographic measurements; and the skin temperature was controlled. Included waveforms were categorized by location and averaged by individual for comparative analysis to electrodiagnostic testing.
RESULTS: A total of 416 waveforms were collected, and 245 were retained for statistical analysis based on strict inclusion criteria. The mean spectral peak velocity among all waveforms was 4.42 (SD, 2.15) cm/s. At the level of the pisiform, the most consistent data point, mean peak systole, was 3.75 cm/s in symptomatic patients versus 4.26 cm/s in asymptomatic controls. Statistical trending showed an initial increase in the mean spectral peak velocity in symptomatic but diagnostically negative cases, with decreasing velocity as diagnostic categories progressed from mild to severe.
CONCLUSIONS: An inverse relationship may exist between intraneural vascular flow in the median nerve and an increasing severity of carpal tunnel syndrome based on nerve conduction results. Randomized controlled trials are needed to determine whether spectral Doppler sonography can provide an additive benefit for diagnosing the severity of carpal tunnel syndrome.

Evans, K. D., Volz, K. R., Hutmire, C., & Roll, S. C. (2012). Morphologic characterization of intraneural flow associated with median nerve pathology. Journal of Diagnostic Medical Sonography, 28, 11-19. Show abstractHide abstract

A prospective cohort of 47 symptomatic patients who reported for nerve conduction studies and 44 asymptomatic controls was examined with sonography to evaluate the median nerve. Doppler studies of the median nerve were collected with handheld sonography equipment and a 12-MHz linear broadband transducer. Strict inclusion criteria were established for assessing 435 waveforms from 166 wrists. Two sonographers agreed that 245 waveforms met the a priori criteria and analyzed the corresponding data. Spectral Doppler waveforms provided direct quantitative and qualitative data for comparison with indirect provocative testing results. These Doppler data were compared between the recruitment groups. No statistical difference existed in waveforms between the groups (P < .05). Trending of the overall data indicated that as the number of positive provocative tests increased, the mean peak systolic velocity within the carpal tunnel (mid) also increased, whereas the proximal mean peak systolic velocity decreased. However, by using multiple provocative tests as an indirect comparative measure, researchers may find mean peak spectral velocity at the carpal tunnel inlet a helpful direct measure in identifying patients with carpal tunnel syndrome.

Roll, S. C., Evans, K. D., Li, X., Freimer, M., & Sommerich, C. M. (2011). Screening for carpal tunnel syndrome using ultrasonography. Journal of Ultrasound in Medicine, 30, 1657-1667. Full text Show abstractHide abstract

OBJECTIVE: The use of ultrasonography in musculoskeletal research and clinical applications is increasing; however, measurement techniques for diagnosing carpal tunnel syndrome (CTS) with ultrasonography continue to be inconsistent. Novel methods of measurement utilizing internal comparisons to identify swelling of the median nerve (MN) require investigation and comparison to currently used techniques.
METHODS: Flattening ratio of the MN, bowing of the flexor retinaculum, and cross-sectional area (CSA) of the MN were collected at the forearm, at the radio-carpal joint, and at the level of the pisiform in both symptomatic patients and asymptomatic controls. Electrodiagnostic testing (EDX) was completed in symptomatic patients as a diagnostic standard.
RESULTS: MN measurements were collected from 166 wrists of symptomatic and asymptomatic subjects. Flattening ratio did not show any correlation to EDX and was identical between both symptomatic and asymptomatic subjects. Moderate to strong correlations were noted between EDX results and ultrasonographic measures of CSA at the pisiform, retinacular bowing, and both ratio and change of CSA between the forearm and pisiform. Area under the curve was large for all receiver operating curves for each measure [.759-.899] and sensitivity was high [80.4%-82.4%].
CONCLUSIONS: Measurement of swelling through a ratio or absolute change had similar diagnostic accuracy as individual measurement of CSA within the carpal tunnel. These measures may be useful to improve accuracy in more diverse clinical populations. Further refinement of protocols to identify the largest CSA within the carpal tunnel region and statistical methods to analyze clustered, multi-level outcome data is recommended to improve diagnostics.

Roll, S. C., Case-Smith, J., & Evans, K. D. (2011). Diagnostic accuracy of ultrasonography versus electromyography in carpal tunnel syndrome: A systematic review of literature. Ultrasound in Medicine and Biology, 37, 1539-1553. Show abstractHide abstract

A plethora of research evaluates the utility of ultrasonography versus electrodiagnostic testing for diagnosis of carpal tunnel syndrome. Two limited reviews of literature were completed, but a full, systematic review has not been completed. We identified 582 abstracts published 1999-2009 through database searches, hand searches, and communication with authors, resulting in 23 high quality studies that met our inclusion criteria based on a rigorous, independent review. Significant discrepancies and methodological limitations in the description of ultrasonography protocols and diagnostic thresholds limited the ability to combine data and identify specific thresholds. The cross-sectional area of the median nerve within the carpal tunnel is the most stable measure and has high potential to correctly diagnose severe carpal tunnel syndrome. Further investigation of measures, especially those that can diagnose mild cases of CTS, is needed. Suggestions for clinical protocols and the utility of ultrasonography as a screening tool to compliment electrodiagnostic testing are reviewed.

Roll, S. C., & Evans, K. D. (2011). Sonographic representation of bifid median nerve and persistent median artery. Journal of Diagnostic Medical Sonography, 27, 89-94. Show abstractHide abstract

Bifid median nerve and persistent median arteries are natural anatomic variants that exist in a small percentage of the population. This case describes a young woman who was referred for electrodiagnostic (EDX) testing of her right upper extremity because of a one-year history of numbness, tingling, and discomfort in her right upper extremity consistent with carpal tunnel syndrome. Careful sonographic scanning (gray scale and power Doppler) and dynamic investigation revealed a bifid median nerve and associated persistent median artery (PMA). The awareness of a bifid median nerve and PMA is important when evaluating patients sonographically for diagnosis of upper extremity pathology, including enlargement due to carpal tunnel syndrome. Furthermore, as musculoskeletal sonography increases in clinical practice, it is important to raise awareness of this dual anatomic variant to ensure that appropriate evaluation and treatment are provided. The sonographic presentation of anatomic variations in this case along with a review of these anomalies is provided for translational clinical use.

Evans, K. D., Roll, S. C., Hutmire, C. D., & Baker, J. P. (2010). Factors that contribute to wrist-hand-finger discomfort in diagnostic medical sonographers and vascular technologists. Journal of Diagnostic Medical Sonography, 26, 121-129. Show abstractHide abstract

A cross-sectional representative sample of 1722 sonographers and vascular technologists was analyzed using quantitative/qualitative methods to reveal that 60% are experiencing wrist-hand-finger discomfort, believed to be from work-related repetitive injury. The years of scanning accumulated by the participants was chosen as a variable to determine the relationship to the range of discomforts reported. A strong statistical correlation was noted between years of experience and the side of discomfort as well as the severity of hand-wrist-finger discomfort. In this study, a strong statistical association was also noted between increasing years of scanning and decreasing aggravation due to the transducer. A complete linkage between work-related exposure and hand-wrist-finger discomfort is difficult to make because of the contribution of leisure-time activities. A controlled experimental study is needed to determine the contribution that grip and pushing on the transducer may have on the incidence of hand-wrist-finger discomfort, leading to diagnoses such as carpal tunnel syndrome.

Evans, K. D., Roll, S. C., Li, X., & Sammet, S. (2010). A holistic evaluation of risk factors for work related musculoskeletal distress among asymptomatic sonographers performing neurosonology: A pilot study. Journal of Diagnostic Medical Sonography, 26, 64-78. Show abstractHide abstract

A pilot study was conducted to gather holistic data points on female sonographers who executed neonatal neurosonography over four portable scanning sessions. The hypothesis was that specific risk factors contributed to work-related musculoskeletal distress in the hand and wrist as a result of neonatal neurosonography. A preexperimental pre-post research design was used to gather data on work demands, self-rated physical and mental health, posture/position during scanning, physiologic change, and pain scores. No statistically significant changes were detected between pre-post measures for work demands, physical and mental health, or pain scores as a result of portable scanning sessions. The physiologic changes, between scanning sessions, were recorded with the use of a hand-carried sonographic unit. Sonographic measures were less than the published criteria for carpal tunnel syndrome with a proximal cross-sectional area ≥10 mm2 and an anterior bulge of the retinaculum of >4 mm. Sonography documented a statistically significant cross-sectional area change, within the median nerve, at the distal radius only after the first scanning session. Power and spectral Doppler was used to document perineural vascular flow within the median nerve, but it was not consistently obtained to allow for a rigorous comparison between pre- and post-scanning sessions. This is the first pilot study to explore using a hand-carried sonographic unit to document change in the median nerve for an isolated sonographic examination. The results are only reflective of these particular participants, but much larger N and shorter scanning sessions are needed to confirm the hypothesis proposed.

Evans, K. D., Roll, S. C., & Baker, J. (2009). Work-related musculoskeletal disorders (WRMDS) among registered diagnostic medical sonographers and vascular technologists: A representative sample. Journal of Diagnostic Medical Sonography, 25, 287-299. Show abstractHide abstract

Literature indicates a significant history of workr-elated musculoskeletal disorders (WRMSD) among diagnostic medical sonographers (DMS) and vascular technologist (VTs). To gather current data related to this historical trend, the authors administered a survey to a random and convenient sample of 5200 registered DMS and VTs. The invitation to complete the survey on a secure Web site yielded the largest participant sample to date of 2963 completed surveys (57% response). Data relative to the prevalence of WRMSD were analyzed and compared to other WRMSD research over the past decade. Results indicated that 90% of respondents were scanning in pain, a 9% increase since the last large scale survey in 1997. Across all demographics, shoulder pain is most common, with older and more experienced sonographers having more finger, hand, and wrist pain than other groups. Pain continues to be related to pressure applied to the transducer, abduction of the arm, and twisting of the neck and trunk. Ergonomic equipment and education are provided by application specialists, but the incidence of WRMSD appears to be unabated. Higher order research, including randomized trials, with education and ergonomic interventions is needed to protect DMS and VTs who are necessary to meet increasing health care demands.

Roll, S. C., & Evans, K. D. (2009). Feasibility of using a hand-carried sonographic unit for investigating median nerve pathology. Journal of Diagnostic Medical Sonography, 25, 241-249. Show abstractHide abstract

Numerous research studies describe the prevalence of work-related musculoskeletal disorders (WRMSD) in diagnostic medical sonographers, but little research has investigated contributing factors and biological changes in symptomatic individuals. Improved image quality and portability, combined with lower cost and dynamic capabilities, have led to increased use of sonography over magnetic resonance imaging (MRI) in musculoskeletal evaluations. The purpose of this pilot study was to develop a valid and reliable sonographic protocol for the evaluation of work-related median nerve pathology with a hand-carried sonographic unit. A GE Logiq I (Milwaukee, Wisconsin) hand-carried unit with a 12-MHz linear transducer was used to collect nine longitudinal and transverse images of the median nerve at various anatomical locations in the distal upper extremity of three healthy volunteers. Doppler waveforms were also collected in the median nerve sheath. Qualitative review indicated high-quality images with well-defined structures, resulting in valid measures between multiple researchers of anteriorposterior diameter, cross-sectional area, anterior transverse carpal ligament bulge, and Doppler flow. The use of a hand-carried sonographic unit appears to be a feasible alternative to MRI to detect musculoskeletal changes in symptomatic sonographers. Additional basic and clinical studies are necessary to validate the use of hand-carried sonography as a measure of biological changes in longitudinal WRMSD research.

Conference Presentations/Proceedings

Roll, S. C., McLaughlin-Gray, J., & Frank, G. (2015). Competency development and complexities of clinical integration of musculoskeletal sonography by non-physician rehabilitation providers [Paper presented at the 2015 AIUM Annual Convention and Preconvention Program Hosting WFUMB Congress]. Ultrasound in Medicine and Biology, 41, S20. Show abstractHide abstract

OBJECTIVES: Non-physician rehabilitation providers (e.g., occupational/physical therapists) have requisite expertise for effective use of point-of-care musculoskeletal sonography (MSKUS); however, professional curriculums provide only introductory-level image interpretation, at best. This multi-method study evaluated post-professional competency development and the complexities of clinical integration of MSKUS by non-physician rehabilitation providers.
METHODS: Three occupational therapists (OTs) received weekly, 2-3 hour, hands-on training from a RMSK-credentialed OT for 3 months. Training included ultrasound physics, imaging protocols, image acquisition, optimization and analysis. Prior to implementing MSKUS in the hand therapy clinic, minmum competency for selecting protocols, acquiring and interpreating images was determined using patient scenerios. During a 10-month implementation, therapists self-rated competency in image acquisition and interpretation on a 10-point visual analogue scale following each MSKUS use. Data were divided into early, mid, and late time periods to evaluate competency development. Semi-structured interviews throughout and following implementation provided deeper understanding of the complexities of clinical integration. Three researchers identified themes through interative anlaysis of interview transcripts and multiple consensus meetings.
RESULTS: Competency for acquiring images significantly increased (p<.05) between the early and mid phase (4.9 to 6.9), whereas competency for image interpretation did not show a significant increase until the late phase (5.8 to 7.6). Qualitative themes included numerous technical competencies nested within real-time interaction with the client, as well as perceived clinical use and professional constraints.
CONCLUSIONS: Utilization of MSKUS by non-physician rehabilitation providers diverged from diagnostic techniques to patient-centered applications (e.g., education, biofeedback). Post-professional MSKUS training programs for these providers will require an unique approach to address the various nested competencies and clinical considerations that differ from training provided to physicians and sonographers.

Roll, S. C., Rana, M., Sigward, S., Yani, M., Kirages, D., & Kutch, J. (2015). Cadaveric validation and in-vivo measurement reliability of a novel linear-array transperineal sonographic evaluation of male pelvic floor structures [Electronic poster presented at the 2015 AIUM Annual Convention and Preconvention Program Hosting WFUMB Congress]. Ultrasound in Medicine and Biology, 41, S103. Show abstractHide abstract

OBJECTIVES:Rigorous reliability and validity data for emerging male pelvic floor imaging protocols has not been reported. This study validated and examined reliability of a novel linear-array, transperineal sonographic approach for evaluating superficial male pelvic floor structures.
METHODS: The superficial pelvic muscles (bulbospongiosus (BS), ischiocavernosus (IC), bony landmarks, and the bulb of the penis were identified via dissection of two embalmed male cadavers. Relative depth and orientation of these structures were compared to sonograms obtained from two male participants, resulting in standardization of the imaging protocol and providing face validity for image analysis. Transverse images were then obtained from 20 male participants (GE Logiq E9, 11-Linear) at two time points. Three raters measured cross-sectional area (CSA) and linear thickness of the bulb of the penis, urethra, BS and IC muscles in three seperate trials for each of 38 images (2 participants lost to follow-up). Two-way, mixed effects intra-class correlation coefficients (ICC) were calculated within repeated trials by rater (intra-rater) and across raters (inter-rater). Minimum acceptable reliability for this study was set at 0.60.
RESULTS: Measures of the bulb of the penis had excellent reliability (ICC > 0.90), CSA of all muscles had good reliability (ICC [0.70-0.92]), and thickness of the BS near its central tendon had good reliability (ICC > 0.80). For rater identified thickest region of the muscles and all urethra measures, reliability was poor-to-fair (ICC [0.50-0.85]) and varied widely, with most lower bounds of confidence intervals falling below the acceptability threshold (<0.60). Intra-rater reliability was similar across the three raters who had varied sonography experience and pelvic knoweldge.
CONCLUSIONS: The superficial structures of the male pelvic floor can validly identified and CSAs can be reliably measured using this sonographic approach. This approach can be used to advance knoweldge and practice for patients with pelvic disorders through the investigation of morphologic differences from healthy controls and the evaluation of clinical intervention effects.

Roll, S. C., Evans, K. D., Volz, K. R., & Sommerich, C. M. (2013). Longitudinal analysis of grayscale imaging and electromyography in an animal model of carpal tunnel syndrome. Journal of Ultrasound in Medicine, 32(Suppl), S49.

Roll, S. C., Evans, K. D., Freimer, M. L., Case-Smith, J., & Sommerich, C. M. (2011). Relationship of median nerve ultrasonographic measures to anthropometric and demographic factors for diagnosis of carpal tunnel syndrome [Paper presented at the 13th World Congress of the World Federation for Ultrasound in Medicine and Biology, Vienna, Austria]. Official proceedings of the 13th Congress of the WFUMB 2011, 37(8S), S6-7. Show abstractHide abstract

PURPOSE: Numerous anthropometric measures, demographic characteristics, and occupational exposures have been suggested as contributory factors in development of carpal tunnel syndrome (CTS). This study investigated the relationship of these factors and physiologic changes in the median nerve (MN) measured with grey-scale ultrasonography (US) to symptoms of MN pathology.
MATERIAL & METHODS: Age, gender, body mass index (BMI), wrist ratio, education, occupation, and MN US measures were collected (n = 88). The Boston Carpal Tunnel Questionnaire (BCTQ) identified complaints of MN pathology. Binary stepwise logistic regression was used to determine the contribution of US measures of cross-sectional area at the pisiform (CSAp), CSA change (forearm-pisiform), and retinacular bulge when considered with known factors in a model for predicting CTS complaints.
RESULTS: Symptoms of MN pathology were reported by 56 subjects. BMI, education and CSAp were significant predictors of complaints in this exploratory regression model (r2 = 0.26, p = 0.001). CSAp odds ratio was 1.35 (p = .001) and BMI odds ratio was 1.10 (p = .04). Odds of complaints decreased as subjects moved from high school education to graduate education (0.535, p = .08).
CONCLUSION: This preliminary study indicates that changes in US measures of the MN nerve may provide more relevant information for predicting MN pathology than other previously studied factors. While larger homogeneous samples are required to validate these findings, these data provide evidence for continued investigation of US as a screening tool for MN pathology.

Evans, K. D., Roll, S. C., Volz, K. R., & Sommerich, C. M. (2011). Spectral Doppler measurement of perineural flow within the median nerve compared to nerve conduction studies [Paper presented at the 13th World Congress of the World Federation for Ultrasound in Medicine and Biology, Vienna, Austria]. Official proceedings of the 13th Congress of the WFUMB 2011, 37(8S), S6. Show abstractHide abstract

PURPOSE: To document and analyze perineural vascular flow within the median nerve utilizing power Doppler (PD) and spectral Doppler (SD) to determine a relationship with a nerve conduction study (NCS), for carpal tunnel syndrome (CTS) screening.
MATERIAL & METHODS: PD and SD in the median nerve were prospectively collected with 47 symptomatic and 44 asymptomatic subjects. Doppler studies were conducted using GE Logiq i ultrasound equipment and a 12 MHz linear transducer. Strict inclusion criteria were established for post-examination assessment of waveforms. Median systolic peak measurements taken proximal, mid, and distal to the carpal tunnel inlet were categorized by location and averaged by individual for comparative analysis to NCS results.
RESULTS: The data from all groups were statistically comparable with 27 waveforms at proximal, 42 at the mid, and 54 at the distal portion of the wrist. Control and negative NCS subjects had a mean spectral peak of 4.0 cm/sec. and severe NCS subjects had a spectral peak of 2.3 cm/sec. Statistical trending demonstrated that mean spectral peak data dropped as the diagnostic categories progressed from negative to severe.
CONCLUSION: An inverse relationship may exist between perineural vascular flow in the median nerve and increasing severity of nerve conduction, at the carpal tunnel inlet and distally. Further research is needed to determine if SD is a non-invasive alternative for diagnosing the severity of CTS.

Evans, K. D., Roll, S. C., Volz, K. R., Buford, J. A., & Sommerich, C. M. (2011). Ultrasound contrast-enhanced interrogation of the median nerve to document peripheral vascular flow in an animal model [Paper presented at the 13th World Congress of the World Federation for Ultrasound in Medicine and Biology, Vienna, Austria]. Official proceedings of the 13th Congress of the WFUMB 2011, 37(8S), S6. Show abstractHide abstract

PURPOSE: To identify dosing and instrumentation while conducting contrast sonography to visualize perineural vascular flow, within the median nerve, in a group of Macaca fascicularis recovering from carpal tunnel syndrome (CTS).
MATERIAL & METHODS: A pilot dosing study was conducted with Macaca fascicularis, which were trained to complete a repetitive task. Nerve conduction and gray-scale sonography data were collected on 8 subjects with documented CTS. The dosing study facilitated the capture of vascular fill time within both large and small vessels. Dosing and instrumentation were set using the subclavian and radial artery, to determine a mean vascular fill time. The Doppler studies were conducted with a GE Logiq 9 and a 9 MHz linear array transducer. Definity(R) was mixed with saline to provide an infusion contrast injection. Four injections and booster shots were administered while the subject was closely monitored.
RESULTS: A transmit frequency of 6.0 MHz, MI of 0.13, and 7% output power was coupled with an infusion of 0.04 ml of Definity(R) and 0.8 ml saline. Booster infusions of 0.05 facilitated the capture of a vascular fill time of 1:30 mins in the subclavian and radial artery. The perineural vascular fill time was similar with these same infusion and equipment settings.
CONCLUSION: Although data was collected on 8 subjects, more subject results would provide convincing results on the vascular fill time associated with perineural vascular flow, post CTS diagnosis.

Sommerich, C. M., Gumpina, R., Roll, S. C., Le, P., & Chandler, D. (2009, May). Investigating effects of controller algorithm on torque tool operator. Paper presented at the 2009 Industrial Engineering Research Conference, Miami, FL.