Evidence-Based Imaging L. Santiago Medina, MD, MPH Director, Health Outcomes, Policy and Economics (HOPE) Center, Co-Director Division of Neuroradiology, Department of Radiology, Miami Children’s Hospital, Miami, Florida Former Lecturer in Radiology, Harvard Medical School, Boston, Massachusetts C. Craig Blackmore, MD, MPH Professor, Department of Radiology, Adjunct Professor, Health Services, University of Washington, Co-Director Radiology Health Services Research Section, Harborview Injury Prevention and Research Center, Seattle, Washington Evidence-Based Imaging Optimizing Imaging in Patient Care With 183 Illustrations, 14 in Full Color With a CD-ROM Foreword by Bruce J. Hillman, MD L. Santiago Medina, MD, MPH C. Craig Blackmore, MD, MPH Director Professor Health Outcomes Department of Radiology Policy and Economics (HOPE) Center Adjunct Professor Health Services Co-Director Division of Neuroradiology University of Washington Department of Radiology Co-Director Radiology Health Miami Children’s Hospital Services Research Section Miami, FL33155 Harborview Injury Prevention Former Lecturer in Radiology and Research Center Harvard Medical School Seattle, WA98104 Boston, MA02114 USA USA Library of Congress Control Number: 2005925501 ISBN 10: 0-387-25916-3 ISBN 13: 987-0387-25916-1 Printed on acid-free paper. © 2006 Springer Science+Business Media, Inc. All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, Inc., 233 Spring Street, New York, NY10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. 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To our families, friends, and mentors. Foreword Despite our best intentions, most of what constitutes modern medical imaging practice is based on habit, anecdotes, and scientific writings that are too often fraught with biases. Best estimates suggest that only around 30% of what constitutes “imaging knowledge” is substantiated by reliable scientific inquiry. This poses problems for clinicians and radiologists, because inevitably, much of what we do for patients ends up being inef- ficient, inefficacious, or occasionally even harmful. In recent years, recognition of how the unsubstantiated practice of medicine can result in poor-quality care and poorer health outcomes has led to a number of initiatives. Most significant in my mind is the evidence- based medicine movement that seeks to improve clinical research and research synthesis as a means of providing a more definitive knowledge basis for medical practice. Although the roots of evidence-based medicine are in fields other than radiology, in recent years, a number of radiologists have emerged to assume leadership roles. Many are represented among the authors and editors of this excellent book, the purpose of which is to enhance understanding of what constitutes the evidence basis for the prac- tice of medical imaging and where that evidence basis is lacking. It comes not a moment too soon, given how much is going on in the regulatory and payer worlds concerning health care quality. There is a general lack of awareness among radiologists about the insubstantiality of the foundations of our practices. Through years of teaching medical stu- dents, radiology residents and fellows, and practicing radiologists in various venues, it occurs to me that at the root of the problem is a lack of sophistication in reading the radiology literature. Many clinicians and radi- ologists are busy physicians, who, over time, have taken more to reading reviews and scanning abstracts than critically examining the source of practice pronouncements. Even in our most esteemed journals, literature reviews tend to be exhaustive regurgitations of everything that has been written, without providing much insight into which studies were per- formed more rigorously, and hence are more believable. Radiology train- ing programs spend inordinate time cramming the best and brightest young minds with acronyms, imaging “signs,” and unsubstantiated factoids while mostly ignoring teaching future radiologists how to think rigorously about what they are reading and hearing. vii viii Foreword As I see it, the aim of this book is nothing less than to begin to reverse these conditions. This book is not a traditional radiology text. Rather, the editors and authors have provided first a framework for how to think about many of the most important imaging issues of our day, and then fleshed out each chapter with a critical review of the information available in the literature. There are a number of very appealing things about the approach employed here. First, the chapter authors are a veritable “who’s who” of the most thoughtful individuals in our field. Reading this book provides a window into how they think as they evaluate the literature and arrive at their conclusions, which we can use as models for our own improvement. Many of the chapters are coauthored by radiologists and practicing clini- cians, allowing for more diverse perspectives. The editors have designed a uniform approach for each chapter and held the authors’ feet to the fire to adhere to it. Chapters 3 to 30 provide, up front, a summary of the key points. The literature reviews that follow are selective and critical, rating the strength of the literature to provide insight for the critical reader into the degree of confidence he or she might have in reviewing the conclu- sions. At the end of each chapter, the authors present the imaging approaches that are best supported by the evidence and discuss the gaps that exist in the evidence that should cause us lingering uncertainty. Figures and tables help focus the reader on the most important informa- tion, while decision trees provide the potential for more active engage- ment. Case studies help actualize the main points brought home in each chapter. At the end of each chapter, bullets are used to highlight areas where there are important gaps in research. The result is a highly approachable text that suits the needs of both the busy practitioner who wants a quick consultation on a patient with whom he or she is actively engaged or the radiologist who wishes a comprehen- sive, in-depth view of an important topic. Most importantly, from my per- spective, the book goes counter to the current trend of “dumbing down” radiology that I abhor in many modern textbooks. To the contrary, this book is an intelligent effort that respects the reader’s potential to think for him- or herself and gives substance to Plutarch’s famous admonition, “The mind is not a vessel to be filled but a fire to be kindled.” Bruce J. Hillman, MD Theodore E. Keats Professor of Radiology University of Virginia Preface All is flux, nothing stays still. Nothing endures but change. Heraclitus, 540–480 B.C. Medical imaging has grown exponentially in the last three decades with the development of many promising and often noninvasive diagnostic studies and therapeutic modalities. The corresponding medical literature has also exploded in volume and can be overwhelming to physicians. In addition, the literature varies in scientific rigor and clinical applicability. The purpose of this book is to employ stringent evidence-based medicine criteria to systematically review the evidence defining the appropriate use of medical imaging, and to present to the reader a concise summary of the best medical imaging choices for patient care. The 30 chapters cover the most prevalent diseases in developed coun- tries including the four major causes of mortality and morbidity: injury, coronary artery disease, cancer, and cerebrovascular disease. Most of the chapters have been written by radiologists and imagers in close collabo- ration with clinical physicians and surgeons to provide a balanced and fair analysis of the different medical topics. In addition, we address in detail both the adult and pediatric sides of the issues. We cannot answer all ques- tions—medical imaging is a delicate balance of science and art, often without data for guidance—but we can empower the reader with the current evidence behind medical imaging. To make the book user-friendly and to enable fast access to pertinent information, we have organized all of the chapters in the same format. The chapters are framed around important and provocative clinical questions relevant to the daily physician’s practice. Ashort table of contents at the beginning of each chapter helps three different tiers of users: (1) the busy physician searching for quick guidance, (2) the meticulous physician seeking deeper understanding, and (3) the medical-imaging researcher requiring a comprehensive resource. Key points and summarized answers to the important clinical issues are at the beginning of the chapters, so the busy clinician can understand the most important evidence-based imaging data in seconds. This fast bottom-line information is also available in a CD- ROM format, so an expeditious search can be done at the medical office or ix x Preface hospital, or at home. Each important question and summary is followed by a detailed discussion of the supporting evidence so that the meticulous physician can have a clear understanding of the science behind the evidence. In each chapter the evidence discussed is presented in tables and figures that provide an easy review in the form of summary tables and flow charts. The imaging case series highlights the strengths and limitations of the dif- ferent imaging studies with vivid examples. Toward the end of the chap- ters, the best imaging protocols are described to ensure that the imaging studies are well standardized and done with the highest available quality. The final section of the chapters is Future Research, in which provocative questions are raised for physicians and nonphysicians interested in advancing medical imaging. Not all research and not all evidence are created equal. Accordingly, throughout the book, we use a four-level classification detailing the strength of the evidence: level I (strong evidence), level II (moderate evidence), level III (limited evidence), and level IV (insufficient evidence). The strength of the evidence is presented in parenthesis throughout the chapter so the reader gets immediate feedback on the weight of the evidence behind each topic. Finally, we had the privilege of working with a group of outstanding contributors from major medical centers and universities in North America and the United Kingdom. We believe that the authors’ expertise, breadth of knowledge, and thoroughness in writing the chapters provide a valu- able source of information and can guide decision making for physicians and patients. In addition to guiding practice, the evidence summarized in the chapters may have policy-making and public health implications. Finally, we hope that the book highlights key points and generates dis- cussion, promoting new ideas for future research. L. Santiago Medina, MD, MPH C. Craig Blackmore, MD, MPH Contents Foreword by Bruce J. Hillman . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv 1 Principles of Evidence-Based Imaging . . . . . . . . . . . . . . . . . . . 1 L. Santiago Medina and C. Craig Blackmore 2 Critically Assessing the Literature: Understanding Error and Bias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 C. Craig Blackmore, L. Santiago Medina, James G. Ravenel, and Gerard A. Silvestri 3 Breast Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Laurie L. Fajardo, Wendie A. Berg, and Robert A. Smith 4 Imaging of Lung Cancer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 James G. Ravenel and Gerard A. Silvestri 5 Imaging-Based Screening for Colorectal Cancer . . . . . . . . . . . . 79 James M.A. Slattery, Lucy E. Modahl, and Michael E. Zalis 6 Imaging of Brain Cancer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 Soonmee Cha 7 Imaging in the Evaluation of Patients with Prostate Cancer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 Jeffrey H. Newhouse 8 Neuroimaging in Alzheimer Disease . . . . . . . . . . . . . . . . . . . . 142 Kejal Kantarci and Clifford R. Jack, Jr. 9 Neuroimaging in Acute Ischemic Stroke . . . . . . . . . . . . . . . . . 160 Katie D. Vo, Weili Lin, and Jin-Moo Lee xi