Clinical Focus

  • Diagnostic Radiology

Academic Appointments

  • Clinical Professor, Radiology

Professional Education

  • Fellowship: Massachusetts General Hospital Musculoskeletal Radiology Fellowship (2008) MA
  • Board Certification: American Board of Radiology, Diagnostic Radiology (2007)
  • Residency: Baylor College of Medicine Radiology Residency (2007) TX
  • Internship: Naval Medical Center (1999) CA
  • Medical Education: Kirksville College of Osteopathic Medicine (1998) MO


All Publications

  • Recognizing and Avoiding the Most Common Mistakes in Quality Improvement. Journal of the American College of Radiology : JACR Larson, D. B., Willis, M. H., Hwang, G. L. 2020

    View details for DOI 10.1016/j.jacr.2020.09.053

    View details for PubMedID 33069677

  • Critical Results in Radiology: Defined by Clinical Judgment or by a List? Journal of the American College of Radiology : JACR Kuhn, K., Larson, D. B., 2020 Radiology Improvement Summit Critical Results Workgroup, Becker, C., Bierhals, A., Broder, J., City, R., Cooke, E., Cordova, D., Curci, N. E., Davenport, M. S., Dinan, D., Duncan, J. R., Dungan, D., Facchini, D., Heller, R. E., Hwang, G., Irani, N., Joshi, A., Kadom, N., Kaplan, S. L., Kolli, K. P., Krishnaraj, A., Marsh, D., Miller, A., Mintz, A., Pahade, J., Policeni, B., Rubio, E. I., Towbin, A. J., Wald, C., Wandtke, B., Willis, M. 2020

    View details for DOI 10.1016/j.jacr.2020.07.009

    View details for PubMedID 32783896

  • Assessment of the Radiology Support, Communication and Alignment Network to Reduce Medical Imaging Overutilization: A Multipractice Cohort Study. Journal of the American College of Radiology : JACR Rezaii, P. G., Fredericks, N., Lincoln, C. M., Hom, J., Willis, M., Burleson, J., Haines, G. R., Chatfield, M., Boothroyd, D., Ding, V. Y., Bello, J. A., McGinty, G. B., Smith, C. D., Yucel, E. K., Hillman, B., Thorwarth, W. T., Wintermark, M. 2020; 17 (5): 597–605


    PURPOSE: The aim of this study was to determine whether participation in Radiology Support, Communication and Alignment Network (R-SCAN) results in a reduction of inappropriate imaging in a wide range of real-world clinical environments.METHODS: This quality improvement study used imaging data from 27 US academic and private practices that completed R-SCAN projects between January 25, 2015, and August 8, 2018. Each project consisted of baseline, educational (intervention), and posteducational phases. Baseline and posteducational imaging cases were rated as high, medium, or low value on the basis of validated ACR Appropriateness Criteria. Four cohorts were generated: a comprehensive cohort that included all eligible practices and three topic-specific cohorts that included practices that completed projects of specific Choosing Wisely topics (pulmonary embolism, adnexal cyst, and low back pain). Changes in the proportion of high-value cases after R-SCAN intervention were assessed for each cohort using generalized estimating equation logistic regression, and changes in the number of low-value cases were analyzed using Poisson regression.RESULTS: Use of R-SCAN in the comprehensive cohort resulted in a greater proportion of high-value imaging cases (from 57% to 79%; odds ratio, 2.69; 95% confidence interval, 1.50-4.86; P= .001) and 345 fewer low-value cases after intervention (incidence rate ratio, 0.45; 95% confidence interval, 0.29-0.70; P < .001). Similar changes in proportion of high-value cases and number of low-value cases were found for the pulmonary embolism, adnexal cyst, and low back pain cohorts.CONCLUSIONS: R-SCAN participation was associated with a reduced likelihood of inappropriate imaging and is thus a promising tool to enhance the quality of patient care and promote wise use of health care resources.

    View details for DOI 10.1016/j.jacr.2020.02.011

    View details for PubMedID 32371000

  • Everything Every Radiologist Always Wanted (and Needs) to Know About Clinical Decision Support. Journal of the American College of Radiology : JACR Wintermark, M., Willis, M. H., Hom, J., Franceschi, A. M., Fotos, J. S., Mosher, T., Cruciata, G., Reuss, T., Horton, R., Fredericks, N., Burleson, J., Haines, B., Bruno, M. 2020; 17 (5): 568–73


    As of January 2020, clinical decision support needs to be implemented across US health systems for advanced diagnostic imaging services. This article reviews the history, importance, and hurdles of clinical decision support and discusses a few pearls and pitfalls regarding its implementation.

    View details for DOI 10.1016/j.jacr.2020.03.016

    View details for PubMedID 32370997

  • Multisite Implementation of Radiology-TEACHES (Technology-Enhanced Appropriateness Criteria Home for Education Simulation). Journal of the American College of Radiology : JACR Willis, M. H., Newell, A. D., Fotos, J., Germaine, P., Gilpin, J. W., Lewis, K., Stein, M. W., Straus, C., Sepulveda, K. A. 2020


    PURPOSE: After encouraging results from a single-institution pilot, a novel case-based education portal using integrated clinical decision support at the simulated point of order entry was implemented at multiple institutions to evaluate whether the program is scalable and results transferable. The program was designed to fill key health systems science gaps in traditional medical education curricula, ultimately aiding the transition from volume to value in health care. The module described uses commonly encountered medical vignettes to provide learners with a low-stakes educational environment to improve their awareness and apply curricular content regarding appropriate resource utilization, patient safety, and cost.METHODS: In 2016 and 2017, the team implemented the modules at eight US medical schools. A total of 199 learners participated in this institutional review board-approved study; 108 completed the module, and 91 were in the control group.RESULTS: The module group had higher posttest scores than their control group peers, after controlling for pretest scores (beta= 4.05, P < .001). The greatest knowledge gains were on questions related to chest radiography (22% improvement) and adnexal cysts (20.33% improvement) and the least on items related to pulmonary embolism (0.33% improvement). The majority of learners expressed satisfaction with the educational content provided (70.4%) and an increased perception to appropriately select imaging studies (65.2%).CONCLUSIONS: This program is promising as a standardized educational resource for widespread implementation in developing health systems science curricula. Learners at multiple institutions judged this educational resource as valuable and, through this initiative, synthesized practice behaviors by applying evidence-based guidelines in a cost-effective, safe, and prudent manner.

    View details for DOI 10.1016/j.jacr.2019.12.012

    View details for PubMedID 31930982

  • Variables Influencing Radiology Volume Recovery During the Next Phase of the Coronavirus Disease 2019 (COVID-19) Pandemic. Journal of the American College of Radiology : JACR Madhuripan, N. n., Man-Ching Cheung, H. n., Alicia Cheong, L. H., Jawahar, A. n., Willis, M. n., Larson, D. B. 2020


    The coronavirus disease 2019 (COVID-19) pandemic has reduced radiology volumes across the country as providers have decreased elective care to minimize the spread of infection and free up health care delivery system capacity. After the stay-at-home order was issued in our county, imaging volumes at our institution decreased to approximately 46% of baseline volumes, similar to the experience of other radiology practices. Given the substantial differences in severity and timing of the disease in different geographic regions, estimating resumption of radiology volumes will be one of the next major challenges for radiology practices. We hypothesize that there are six major variables that will likely predict radiology volumes: (1) severity of disease in the local region, including potential subsequent "waves" of infection; (2) lifting of government social distancing restrictions; (3) patient concern regarding risk of leaving home and entering imaging facilities; (4) management of pent-up demand for imaging delayed during the acute phase of the pandemic, including institutional capacity; (5) impact of the economic downturn on health insurance and ability to pay for imaging; and (6) radiology practice profile reflecting amount of elective imaging performed, including type of patients seen by the radiology practice such as emergency, inpatient, outpatient mix and subspecialty types. We encourage radiology practice leaders to use these and other relevant variables to plan for the coming weeks and to work collaboratively with local health system and governmental leaders to help ensure that needed patient care is restored as quickly as the environment will safely permit.

    View details for DOI 10.1016/j.jacr.2020.05.026

    View details for PubMedID 32505562

  • ACR Statement on Safe Resumption of Routine Radiology Care During the Coronavirus Disease 2019 (COVID-19) Pandemic. Journal of the American College of Radiology : JACR Davenport, M. S., Bruno, M. A., Iyer, R. S., Johnson, A. M., Herrera, R. n., Nicola, G. N., Ortiz, D. n., Pedrosa, I. n., Policeni, B. n., Recht, M. P., Willis, M. n., Zuley, M. L., Weinstein, S. n. 2020


    The ACR recognizes that radiology practices are grappling with when and how to safely resume routine radiology care during the coronavirus disease 2019 (COVID-19) pandemic. Although it is unclear how long the pandemic will last, it may persist for many months. Throughout this time, it will be important to perform safe, comprehensive, and effective care for patients with and patients without COVID-19, recognizing that asymptomatic transmission is common with this disease. Local idiosyncrasies prevent a single prescriptive strategy. However, general considerations can be applied to most practice environments. A comprehensive strategy will include consideration of local COVID-19 statistics; availability of personal protective equipment (PPE); local, state, and federal government mandates; institutional regulatory guidance; local safety measures; health care worker availability; patient and health care worker risk factors; factors specific to the indication(s) for radiology care; and examination or procedure acuity. An accurate risk-benefit analysis of postponing versus performing a given routine radiology examination or procedure often is not possible due to many unknown and complex factors. However, this is the overriding principle: If the risk of illness or death to a health care worker or patient from health care-acquired COVID-19 is greater than the risk of illness or death from delaying radiology care, the care should be delayed; however, if the opposite is true, the radiology care should proceed in a timely fashion.

    View details for DOI 10.1016/j.jacr.2020.05.001

    View details for PubMedID 32442427

    View details for PubMedCentralID PMC7201228

  • Optimizing Performance by Preventing Disruptive Behavior in Radiology. Radiographics : a review publication of the Radiological Society of North America, Inc Willis, M. H., Friedman, E. M., Donnelly, L. F. 2018; 38 (6): 1639–50


    Disruptive behaviors impede delivery of high-value health care by negatively impacting patient outcomes and increasing costs. Health care is brimming with potential triggers of disruptive behavior. Given omnipresent environmental and cultural factors such as constrained resources, stressful environments, commercialization, fatigue, unrealistic expectation of perfectionism, and burdensome documentation, a burnout epidemic is raging, and medical providers are understandably at tremendous risk to succumb and manifest these unprofessional behaviors. Each medical specialty has its own unique challenges. Radiology is not exempt; these issues do not respect specialty or professional boundaries. Unfortunately, preventive measures are too frequently overlooked, provider support programs rarely exist, and often organizations either tolerate or ineffectively manage the downstream disruptive behaviors. This review summarizes the background, key definitions, contributing factors, impact, prevention, and management of disruptive behavior. Every member of the health care team can gain from an improved understanding and awareness of the contributing factors and preventive measures. Application of these principles can foster a just culture of understanding, trust, support, respect, and teamwork balanced with accountability. The authors discuss these general topics along with specific issues for radiologists in the current medical environment. Patients, providers, health care organizations, and society all stand to benefit from better prevention of these behaviors. There is a strong moral, ethical, and business case to address this issue head-on. ©RSNA, 2018.

    View details for DOI 10.1148/rg.2018180019

    View details for PubMedID 30303780

  • Out of the Darkness and Into the Light: Patients, Referring Physicians, and Radiologists Working Toward Patient-and Family-Centered Care in Radiology JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY Cook, T. S., Willis, M. H., Abbott, C., Rawson, J. V., Krishnaraj, A. 2017; 14 (4): 569–72

    View details for DOI 10.1016/j.jacr.2016.08.030

    View details for Web of Science ID 000398652400028

    View details for PubMedID 27884631

  • R-SCAN: CT Angiographic Imaging for Pulmonary Embolism. Journal of the American College of Radiology : JACR Frigini, L. A., Hoxhaj, S. n., Wintermark, M. n., Gibby, C. n., De Rosen, V. L., Willis, M. H. 2017; 14 (5): 637–40

    View details for PubMedID 28284675

  • An Asynchronous Online Collaboration Between Radiologists and Patients: Harnessing the Power of Informatics to Design the Ideal Patient Portal JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY Cook, T. S., Krishnaraj, A., Willis, M. H., Abbott, C., Rawson, J. V. 2016; 13 (12): 1599–1602

    View details for DOI 10.1016/j.jacr.2016.09.040

    View details for Web of Science ID 000389562000011

    View details for PubMedID 27888947

  • A Multispecialty Collaboration to Reduce Unnecessary Imaging for Knee Osteoarthritis JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY Spence, S. C., McAlister, W., Reed, B., Zare, M., Bingham, B., Low, J., Willis, M. 2016; 13 (11): 1343–46

    View details for DOI 10.1016/j.jacr.2016.05.002

    View details for Web of Science ID 000387638400013

    View details for PubMedID 27319371

  • Posterior Root Meniscal Tears: Preoperative, Intraoperative, and Postoperative Imaging for Transtibial Pullout Repair RADIOGRAPHICS Palisch, A. R., Winters, R. R., Willis, M. H., Bray, C. D., Shybut, T. B. 2016; 36 (6): 1792–1806


    The menisci play an important biomechanical role in axial load distribution of the knees by means of hoop strength, which is contingent on intact circumferentially oriented collagen fibers and meniscal root attachments. Disruption of the meniscal root attachments leads to altered biomechanics, resulting in progressive cartilage loss, osteoarthritis, and subchondral edema, with the potential for development of a subchondral insufficiency fracture. Identification of meniscal root tears at magnetic resonance (MR) imaging is crucial because new arthroscopic surgical techniques (transtibial pullout repair) have been developed to repair meniscal root tears and preserve the tibiofemoral cartilage of the knee. An MR imaging classification of posterior medial meniscal root ligament lesions has been recently described that is dedicated to the posterior root of the medial meniscus. An arthroscopic classification of meniscal root tears has been described that can be applied to the anterior and posterior roots of both the medial meniscus and the lateral meniscus. This arthroscopic classification includes type 1, partial stable root tears; type 2, complete radial root tears; type 3, vertical longitudinal bucket-handle tears; type 4, complex oblique tears; and type 5, bone avulsion fractures of the root attachments. Knowledge of these classifications and the potential contraindications to meniscal root repair can aid the radiologist in the preoperative reporting of meniscal root tear types and the evaluation of the tibiofemoral cartilage. As more patients undergo arthroscopic repair of meniscal root tears, familiarity with the surgical technique and the postoperative radiographic and MR imaging appearance is important to adequately report the imaging findings. ©RSNA, 2016.

    View details for DOI 10.1148/rg.2016160026

    View details for Web of Science ID 000388438200012

    View details for PubMedID 27726749

  • Clinical Decision Support at the Point-of-Order Entry: An Education Simulation Pilot with Medical Students. Academic radiology Willis, M. H., Frigini, L. A., Lin, J. n., Wynne, D. M., Sepulveda, K. A. 2016; 23 (10): 1309–18


    We have been called to reform radiology undergraduate medical education (UME) curricula. Clinically available clinical decision support provides an opportunity to improve education regarding appropriate imaging utilization, patient safety, and cost-effective care.We created an education simulation portal utilizing integrated clinical decision support. The portal was then piloted with 34 volunteer medical students at our institution in a blended learning environment. A program assessment was performed utilizing the results from a qualitative survey, pre-test, and post-test.The large majority of medical students felt this supplemental education resource should be included in our UME curriculum (85.29%). All students perceived value in the education simulation portal. The students performed significantly better on the post-test in multiple categories (overall P <.0001), including Choosing Wisely topics (P = .0207).Based on our program assessment from this pilot program, we believe this innovative educational resource has significant potential to fill curricular gaps in radiology UME curricula. This platform is scalable and can be further customized to fill needs across the continuum of medical education.

    View details for DOI 10.1016/j.acra.2016.01.020

    View details for PubMedID 27639160

  • Carpe Diem: Population Health JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY Willis, M. H. 2015; 12 (2): 127–28

    View details for DOI 10.1016/j.jacr.2014.03.013

    View details for Web of Science ID 000348887700004

    View details for PubMedID 24836271

  • Measurement of Ulnar Variance From the Lateral Radiograph: A Comparison of Techniques JOURNAL OF HAND SURGERY-AMERICAN VOLUME Parker, A. S., Minh Nguyen, Minard, C. G., Guffey, D., Willis, M. H., Reichel, L. M. 2014; 39 (6): 1114–21


    To determine the reliability of measuring ulnar variance on lateral wrist radiographs and to compare this technique with previously described methods.Ulnar variance was measured in 100 normal wrist radiographs using the methods of perpendiculars, central reference point, and the lateral radiograph by 3 surgeons on 2 occasions. Intraobserver repeatability and agreement between raters and methods were assessed and compared.Intra- and interobserver reliability and agreement were both excellent using all 3 methods within a ± 1.0-mm cutoff. However, there was substantial pairwise disagreement in measures of ulnar variance between all 3 methods.This study demonstrates that, for measurement of ulnar variance, the methods of perpendiculars, central reference point, and lateral radiographic measurement each have clinically acceptable intraobserver repeatability and interobserver agreement. Despite their independent reliability, each method of radiographic determination of ulnar variance had considerable disagreement with the other methods, indicative of inherent inaccuracies in the techniques. The lateral radiograph uniquely allows for visualization of the amount of ulnar head protruding proximal or distal to the concave lunate facet and allows for a rapid estimation of pronosupination, which is known to affect ulnar variance.Determination of ulnar variance can be an important component of surgical decision making in various pathological conditions of the hand and wrist. Traditionally, it has been measured through methods using the posteroanterior wrist radiograph, but there are potential shortcomings with these methods, and use of the lateral radiograph may provide a more clinically relevant picture of ulnar variance. This study shows that measurement from the lateral radiograph provides similar reliability to previously accepted techniques.

    View details for DOI 10.1016/j.jhsa.2014.03.024

    View details for Web of Science ID 000337011000012

    View details for PubMedID 24810937

  • Clinically Oriented Three-Year Medical Physics Curriculum: A New Design for the Future AMERICAN JOURNAL OF ROENTGENOLOGY Nachiappan, A. C., Lee, S. R., Willis, M. H., Galfione, M. R., Chinnappan, R. R., Diaz-Marchan, P. J., Bushong, S. C. 2012; 199 (3): 635–43


    Medical physics instruction for diagnostic radiology residency at our institution has been redesigned with an interactive and image-based approach that encourages clinical application. The new medical physics curriculum spans the first 3 years of radiology residency and is integrated with the core didactic curriculum.Salient features include clinical medical physics conferences, fundamentals of medical physics lectures, practicums, online modules, journal club, and a final review before the American Board of Radiology core examination.

    View details for DOI 10.2214/AJR.11.7356

    View details for Web of Science ID 000308150000048

    View details for PubMedID 22915405

  • A Proposed Medical Physics Curriculum: Preparing for the 2013 ABR Examination JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY Nachiappan, A. C., Wynne, D. M., Katz, D. P., Willis, M. H., Bushong, S. C. 2011; 8 (1): 53–57


    The upcoming ABR examination format for radiology residents is undergoing significant changes in 2013. This requires adaptation of the didactic curriculum for radiology residents entering in July 2010 to meet these changes. Physics will now be incorporated into the core (qualifying) examination during the third year of residency, instead of being tested as a separate examination that was often taken earlier in residency training in past years. In this article, the authors discuss the past, present, and future of medical physics instruction and outline a revised medical physics curriculum for radiology residents that has been internally approved for implementation at the authors' institution and has not been advocated by any society or by the ABR. Starting with this article, the authors hope to encourage a discussion of physics curriculum revision with other institutions.

    View details for DOI 10.1016/j.jacr.2010.08.016

    View details for Web of Science ID 000305361100012

    View details for PubMedID 21211765

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