Clinical Investigative Studies Perils and Pitfalls of Magnetic Resonance Imaging in the Diagnosis of Multiple Sclerosis ABSTRACT Purpose. Magnetic resonance imaging (MRI) has come to as- sume a position of major importance in the diagnostic process for multiple sclerosis (MS). The authors believe that a tendency toward overreliance on MRI results in isolation from clinical findings continues to result in both false-positive and false-neg- ative diagnostic errors. Methods. To evaluate this, MRI results in newly referred patients with clinical findings suggestive, but not diagnostic, for MS, were studied prospectively. Results. Of 99 consecutive referrals for suspected MS, there were 3 false- positive diagnoses of MS and 7 false-negatives, when the MRis were read in isolation from specific clinical data. None of the scans in the false-negative groups were normal. Representative images of both groups are provided. Conclusion. In newly re- ferred patients who fall short of criteria for definite MS, it re- mains dangerous for both clinicians and radiologists to rely too heavily only on MRI results. Received Sep 8, 1992, and in revised form Nov 6. Accepted for publication Nov 6, 1992. Address correspondence to Dr Schiffer, Department of Neurology, Strong Memorial Hospital, Rochester, NY 14642. R. B. Schiffer, MD Departments of Neurology and Psychiatry School of Medicine and Dentistry University of Rochester Rochester, NY Daniel W. Giang, MD Department of Neurology School of Medicine and Dentistry University of Rochester Alvin Mushlin, MD Departments of Community and Preventative Medicine and Internal Medicine School of Medicine and Dentistry University of Rochester Leena Ketonen, MD, PhD Department of Radiology School of Medicine and Dentistry University of Rochester Stephen Joy, MD Department of Radiology School of Medicine and Dentistry University of Rochester Dan Kido, MD Mallinckrodt Institute of Radiology Washington University Medical Center StLouis, MO AndreW D. Goodman, MD Department of Neurology School of Medicine and Dentistry University of Rochester David H. Mattson, MD, PhD Departments of Neurology and Microbiology and Immunology School of Medicine and Dentistry University of Rochester Cathy Mooney, MS Department of Community and Preventative Medicine School of Medicine and Dentistry University of Rochester The Rochester-Toronto MRI Study Group Schiffer RB, Giang DW, Mushlin A, Ketonen L, Joy S, Kido D, Goodman AD, Mattson DH, Mooney C, the Rochester- Toronto MRI Study Group. Perils and pitfalls of magnetic resonance imaging in the diagnosis of multiple sclerosis. J Neuroimag 1993;3:81-88 In 1986 the authors' group reported a series of clinical features that were warnings or "red flags" for diagnostic errors in multiple sclerosis (MS) [1 ]. In recent years they have been more impressed that diagnostic errors among referrals to their MS clinic are attributable primarily to an overreliance on neuroimaging techniques, particularly magnetic resonance imaging (MRI). This diagnostic issue encompasses both "alpha errors" (MRI scan is normal, therefore diagnosis is not MS) and "beta errors" (MRI scan is abnormal, therefore diagnosis must be MS). Other experienced clinician-investigators recently raised simi- lar concerns [2]. The diagnosis of MS at the present time remains a clinical judgment that must weigh a mix of clinical, lab- oratory, and imaging data [3]. Such judgments must be informed by familiarity with archetypal disease patterns, and they must be tempered by experience. The sensitivity Copyright© 1993 by the American Society of Neuroimaging 81