Principal Consultant:
Matthew D. Mitchell, Ph.D.

• Background
• Research Interests
• Publications
• Presentations

Before founding dr², principal consultant Matthew Mitchell was senior research analyst at ECRI, the leading health technology assessment organization in the United States, and an AHRQ-designated Evidence-Based Practice Center. There he helped develop new technology assessment products and methods, as well as completing scores of assessment reports.

While doing that work, Dr. Mitchell saw numerous opportunities to advance the science of assessing diagnostic tests and improve the quality of the literature, instead of just criticizing it. So in 2005, he resigned from ECRI to open dr² Consulting and seize those opportunities.

Dr. Mitchell's background in radiology goes back to childhood, where he watched his father at work as a radiologist and saw CT scanners and other new technology come into use. While in college, he heard a lecture by Paul Lauterbur (now a Nobel laureate) about a new application of nuclear magnetic resonance to medical imaging, which cemented his interest in the field. He worked for a summer in Lauterbur's laboratory, where some of the first whole-body MR images were acquired, and then opted to do his undergraduate research in the Pendergrass Radiology Research Labs at the University of Pennsylvania.

While at the Pendergrass Labs, Dr. Mitchell developed phantoms for technical evaluation of MR systems, and also conducted the first study proving the diagnostic effectiveness of MRI in comparison to other imaging modalities: a trial comparing MRI to CT and radionuclide bone scanning for diagnosis of avascular necrosis of the hip.

Meanwhile, his writing and communication skills gained notice. He co-authored an early tutorial on MRI, and later co-wrote the chapter on MR spectroscopy in the textbook "Cardiac Imaging."

Dr. Mitchell moved to the Biophysics Graduate Group at Penn to complete his doctoral studies. He worked on numerous MR imaging and spectroscopy projects, developing probes and other hardware, programming pulse sequences, and managing a small-animal MR research facility. He found his niche--at the place where clinicians and researchers meet. While doing that work, he completed his dissertation, on a novel method using deuterium (²H) MRI of heavy water to measure tissue perfusion. He also invented a doubly-driven, double-tuned probe for simultaneous MR imaging and spectroscopy of two different nuclei.

Upon graduation, Dr. Mitchell took a full-time position in the department of Diagnostic Imaging at Thomas Jefferson University. There he was program director for an advanced education program for imaging technologists, developed and taught a variety of courses in the principles and applications of new imaging technology, and hired and supervised eight adjunct faculty members.

Dr. Mitchell's laboratory experience also includes a year with the U.S. Department of Agriculture's Environmental Chemistry Lab, where among other projects, he worked on MRI of fish! The fish (mummichog) came from highly polluted waters in the Chesapeake Bay, and USDA researchers studied them as a living measure of water quality.

Research Interests

Part of the reason Dr. Mitchell began dr² Consulting was to facilitate his continuing research.

His primary research interest is the development and validation of techniques for meta-analysis of diagnostic test trials. He introduced the mean threshold point for reporting summary ROC meta-analysis results, resolved some questions of implementation of the summary ROC, and used a Monte Carlo simulation to validate the logit regression method for calculating the summary ROC.

He also pursues research in the quality of the literature, specifically for clinical trials of diagnostic tests. He has compiled a concordance of checklists for the systematic evaluation of these studies, and reported on the frequency of calculation and other errors in articles included in his technology assessment reports.

ECRI Publications

ECRI has a policy of corporate authorship, and none of the institute's publications are credited to individual authors. However, the following lists are of ECRI reports where I was the primary analyst and author.

Full-Length Technology Assessment Reports

These comprehensive reports are typically 200 to 400 pages in length. They typically include meta-analysis of available research data, and direct comparison of the technology in question to competing technologies. Some reports (e.g. BMD screening and PET for lung cancer) include complete cost-effectiveness or cost-benefit analyses.

• Fetal Fibronectin Assay for Prediction of Preterm Birth and Neonatal Morbidity
• PET for Diagnosis and Staging of Non-Small-Cell Lung Cancer
• Magnetic Resonance Angiography (MRA) of the Head and Neck
• Iontophoresis for Drug Delivery
• Cochlear Implants for Profound Deafness
• Stereotactic Radiosurgery for Intracranial Tumors and Vascular Malformations
• Bone Mineral Density Screening for Osteoporosis
• High Field Strength MRI versus Low Field Strength and Open MRI

Windows on Medical Technology Reports

These are intermediate-form reports (30-60 pages) on specific applications of new medical technologies. Where the evidence base is sufficient, these reports include meta-analysis of published clinical trials, but not cost-effectiveness analysis.

• CT Colonoscopy for Colorectal Cancer Screening
• Dermoscopy for Diagnosis of Melanoma and other Malignancies
• CT Coronary Artery Calcium Measurement
• Botulinum Toxin for Treatment of Hyperhidrosis
• Ultrasound Screening of Normal-Risk Women for Prevention of Post-Term Pregnancy
• Magnetic Resonance Cholangiopanreatography for Diagnosis of Bile Duct Stones
• Computer-Aided Diagnosis in Screening Mammography
• Positron Imaging for Diagnosis of Alzheimer's Disease
• Positron Imaging for Diagnosis and Staging of Breast Cancer
• CT for Lung Cancer Detection
• Hyaluronan-Based Therapy for Osteoarthritis of the Knee
• Magnetic Resonance Imaging for Diagnosis of Breast Cancer
• Positron Imaging for Differentiation of Recurrent Brain Tumor from Radionecrosis
• Proton MR Spectroscopy for Diagnosis of Mitochondrial Metabolic Disorders
• Ultrasound Bone Densitometry for Diagnosis of Osteoporosis
• Alendronate for Prevention of Postmenopausal Osteoporosis
• Alendronate for Treatment of Postmenopausal Osteoporosis
• Doppler Flow Testing of Vascular Access Grafts
• FDG SPECT for Diagnosing Ischemic Heart Disease

Evidence-Based Practice Center reports
(published by Agency for Healthcare Research and Quality)

These reports are produced under a contract to the federal government, answering questions posed by AHRQ, other federal agencies and clinician "science partners." Because of the size and scope of these reports, multiple analysts are assigned to each of them. The following are reports where I was lead analyst for the diagnostic component of the project.

• Diagnosis and Treatment of Swallowing Disorders (Dysphagia) in Acute-Care
• Stroke Patients
• Treatment of Degenerative Lumbar Spinal Stenosis
• Determinants of Disability in Patients With Chronic Renal Failure
• Diagnosis and Treatment of Repetitive Motion Disorders

Other Technology Assessment Reports

Dr. Mitchell was primary author of more than 20 records in the TARGET database of emerging medical technologies and new applications for existing technologies. TARGET records are in a structured format, and include an explanation of how the technology works, the epidemiology of the condition(s) it is used for, a summary of the clinical evidence, and information on regulatory and reimbursement issues.

He also wrote more than 150 rapid-turnaround (3-7 days) Hotline responses on a variety of diagnostic and therapeutic technologies. Hotline responses take the form of a literature search with results reviewed by a research analyst, who writes a commentary on the size and nature of the evidence base to quickly guide users to the most relevant articles. The analyst may also point out controversial aspects of the topic, important research in progress, or threats to the validity of published results.

Invited lectures

• "Systematic Reviews: The Cornerstone Of EBM"; "Evaluating Study Quality"; "Performing A Quantitative Systematic Review." Middle East Evidence-Based Medicine Forum, Dubai, 2004 (cancelled by sponsor)
• "When a Test is not a Diagnostic." ECRI Health Technology Assessment Conference, Plymouth Meeting, 2003
• "CT Coronary Calcium Screening." Center for Medicare and Medicaid Services Cardiology CME Program, Baltimore, 2003.
• "Introduction to Statistical Concepts." ECRI Health Technology Assessment Conference, Plymouth Meeting, 2002
• "Diagnostic Meta-Analysis." International Society for Technology Assessment in Health Care, Berlin, 2002
• "The ECRI approach to rapid HTA" International Society for Technology Assessment in Health Care, Berlin, 2002
• "How to Tell a Good Diagnostic TA from a Bad One." International Society for Technology Assessment in Health Care, Philadelphia, 2001.
• "Think Like a Diagnostician." ECRI Health Technology Assessment Conference, Plymouth Meeting, 2000.
• "A Primer on Assessing Diagnostic Tests." ECRI Health Technology Assessment Conference, Plymouth Meeting, 1999.
• "Publishing Results that are Useful for Technology Assessment." Society for Health Services Research in Radiology, Providence, 1998.
• "Thyroid Cancer Screening: Recommendations of Others." Workshop on Thyroid Cancer Screening and Health Implications of Exposure to Radioactive Iodine Fallout, Institute of Medicine, Washington, 1998

Scientific presentations

• Summary ROC Calculations Should Include the Continuity Correction. Matthew D. Mitchell. International Society for Technology Assessment in Health Care, Philadelphia, 2001.
• Positron Imaging for Differentiation of Recurrent Brain Tumor from Radionecrosis. Matthew D. Mitchell. International Society for Technology Assessment in Health Care, Philadelphia, 2001.
• Temporomandibular Joint Articular Disorders: A Technology Assessment of Selected Non-Surgical and Surgical Treatments. James T. Reston et al. International Society for Technology Assessment in Health Care, Philadelphia, 2001.
• Validation Studies of Summary ROC Meta-Analysis. Matthew D. Mitchell. Society for Health Services Research in Radiology, Arlington, 2000.
• How are Summary ROC Meta-Analysis Results Affected by Method Variations?. Matthew D. Mitchell. International Society for Technology Assessment in Health Care, The Hague, 2000.
• Prostate Cancer Screening with PSA: a Markov Process Cost-Effectiveness Analysis. David L. Doggett, Matthew D. Mitchell, Karyn A. Tappe, Charles W. Turkelson. International Society for Technology Assessment in Health Care, The Hague, 2000.
• Automated Cervical Cancer Screening Technologies for Slide Preparation and Assisted Screening: Analysis and Comparison. Karyn Tappe, Matthew Mitchell, David Doggett. International Society for Technology Assessment in Health Care, The Hague, 2000.
• Unresolved Questions in Summary ROC Meta-Analysis. Matthew D. Mitchell. Society for Health Services Research in Radiology, Washington 1999.
• Sensitivity/Specificity at Mean Threshold: a Convenient Description of Summary ROC Results. Matthew D. Mitchell. International Society for Technology Assessment in Health Care, Ottawa, 1998.
• Cost-effectiveness analysis of PET in lung cancer diagnosis and staging. Matthew D. Mitchell, Charles Turkelson, David Doggett. International Society for Technology Assessment in Health Care, Ottawa, 1998.
• Sensitivity/Specificity at Mean Threshold: a Convenient Description of Summary ROC Results. Matthew D. Mitchell. Society for Health Services Research in Radiology, Philadelphia, 1997.
• Advanced Education: A Necessity for Success in MR. Matthew D. Mitchell. Society of Magnetic Resonance Imaging, New York, 1992.
• MRI of an Unusual Pediatric Liver Tumor. Tammy A. Duffy and Matthew Mitchell. Society of Magnetic Resonance Imaging, New York, 1992.
• MRI vs. Ultrasound in Evaluation of Pregnant Patients. Shirin Karsan and Matthew Mitchell. Society of Magnetic Resonance Imaging, New York, 1992.
• Laminar Flow in Tracer Measurements Leads to Underestimation of Perfusion. Matthew D. Mitchell, Haywood Blum, Mary D. Osbakken. Biophysical Society, Houston, 1992.
• Comparison Between Blood Flow and Deuterium Washout Perfusion in the Isolated Dog Gastrocnemius. Haywood Blum, Matthew D. Mitchell, Shoko Nioka, Michael C. Hogan, William Brechue, Britton Chance. Society of Magnetic Resonance in Medicine, San Francisco, 1991.
• A Doubly-Driven Multiply-Tuned Probe for In Vivo NMR. Matthew D. Mitchell and Haywood Blum. Society of Magnetic Resonance in Medicine, San Francisco, 1991.
• A Non-Physiological Cause for D₂O 'Washout.' Matthew D. Mitchell, Haywood Blum. Society of Magnetic Resonance in Medicine, New York, 1990.
• CBF Measurement by ²H NMR Spectroscopy with Intravenous Tracer Injection. Dea Nagy, Shoko Nioka, Dai-Ju Wang, Matthew D. Mitchell, Britton Chance. Society of Magnetic Resonance in Medicine New York, 1990.
• Measurement of Regional Cerebral Blood Flow in Cat Brain Using Intracarotid Injection of D₂O and ²H-NMR Imaging. John A. Detre, V. Harihara Subramanian, Matthew D. Mitchell, David S. Smith, John S. Leigh, Jr. Society of Magnetic Resonance in Medicine Amsterdam, 1989.
• Measurement of Cerebral Blood Flow in Cat Brain Using Intracarotid Injection of D2O and 2H-NMR Spectroscopy. John A. Detre, Matthew D. Mitchell, David S. Smith, Aziza Zaman, Hiroshi Myake, Shoko Nioka, Michael B. Maris, John S. Leigh, Jr. Society of Magnetic Resonance in Medicine, Amsterdam, 1989.
• Integrated Evaluation of Cardiac Function with ²H and ³¹P NMR and NADH Fluorometry Techniques. Matthew Mitchell, Mary Osbakken, Christopher Duska, Ihor Ponomarenko, Danning Zhang, Avraham Mayevsky, Britton Chance. Society of Magnetic Resonance in Medicine, Amsterdam, 1989.
• Correlation of Myocardial Perfusion, Metabolism, and Mechanical Function During Increased Cardiac Work. Mary Osbakken, Matthew Mitchell, Christopher Duska, Ihor Ponomarenko, Danning Zhang, Avraham Mayevsky. American Physiological Society, New Orleans, 1989.
• An Advanced-Placement Program in MR Technologist Training. Matthew D. Mitchell, Gerald J. Conlogue, Swapan K. Sen, Albert D. Herbert, Jr. Society of Magnetic Resonance in Medicine, San Francisco, 1988.
• Simultaneous In-Vivo Phosphorus Metabolic Spectroscopy and Deuterium Perfusion Measurement. Matthew D. Mitchell, Bernard J. Clark, John S. Leigh, Jr. Society of Magnetic Resonance in Medicine, New York, 1987.
• Avascular Necrosis of the Hip: Comparison of MR, CT, and Scintigraphy. Abass Alavi, Matthew D. Mitchell, Harold L. Kundel, Marvin E. Steinberg, Herbert Y. Kressel, Leon Axel. Society of Nuclear Medicine, 1986.
• Adjustment of T1 and T2 in H₂O/D₂O Solutions and Agarose Gels. Matthew D. Mitchell, Harold L. Kundel. Society of Magnetic Resonance in Medicine, London, 1985.
• Statistical Evaluation of MRI in Diagnosis of AVN of the Hip. Matthew D. Mitchell, Harold L. Kundel, Herbert Y. Kressel, Abass Alavi, Marvin E. Steinberg. Society of Magnetic Resonance in Medicine, London, 1985.
• Comparison of MR, CT, and RN Imaging of AVN of the Hip Using ROC Curves. Harold L. Kundel, Matthew D. Mitchell, Marvin E. Steinberg, Herbert Y. Kressel, Abass Alavi. Radiological Society of North America, Washington, 1984. Radiology 153(P):137 (1984).
• Agarose Gels for NMR Phantoms. Matthew D. Mitchell, Harold L. Kundel, Leon Axel. Society of Magnetic Resonance in Medicine, San Francisco, 1983. Mag. Res. Med. 1:207 (1984).
• An Agarose Gel Model for Tissue Proton Relaxation. Matthew D. Mitchell, Harold L. Kundel, Leon Axel. Society of Magnetic Resonance in Medicine, San Francisco, 1983. Mag. Res. Med. 1:206 (1984).

• Background
• Research Interests
• Publications
• Presentations