condition most frequently cited in failure-to-diagnose claims, and because these types of claims are increasing, more pressure will likely be placed on providers to increase ordering so as to avoid being sued [24]. A potential defense based on the con- cept that a radiologist on other physician refrained from ordering a radiologic test because of its low cost-effectiveness is not likely to be convincing and may well, in fact, serve only to antagonize a jury or judge [22]. Radiologic Misses Allegations of missed diagnoses have consistently been the mostfrequent cause of radiologic malpractice litigation throughout the 20-year reporting period. Table 1 and Figure 2 reveal thatthe proportion of lawsuits claiming missed diagnoses to the total number of radiology-related cases has ranged from an annual low of 29% in 1975 to a high of 59% in 1983 and 1991, with a 20-year average of 42%. A more realistic picture as it applies to the diagnostic radiologist, however, is obtained if the number of lawsuits claiming misses is compared with radiology lawsuits that do not include radiation oncology and failure-toorder categories. Under this scenario, the allegation of missed radiologic diagnosis accounts for an average of 59% of all cases overthe 20-year period, with a low of 55% during the first S years and a high of 71% in the 5-year period ending 1994. The total number of missed-diagnosis lawsuits hit a high in 1985, dropped somewhat over the next 4 years, and then began rising again. A look at the types of diagnoses missed is revealing. Table S and Figure 4, which break down the 1975- 1994 period into four S-year segments, show that litigation related to missed bone abnormalities of all types, including fractunes, dislocations, malignant lesions, inflammations, and other nonspecified conditions, accounted for the greatest percentage of cases for the first 10 years but then dropped precipitously over the past 10 years. It barely still leads the list. The number of lawsuits changing missed GI lesions have remained low but constant over all time periods. Missed malignant lesions of the lung reached a high in the second 5-year reporting period, decreased slightly thereafter, but have been constant over the past two S-year blocks. The trend for claims alleging missed breast cancers on mammograms is striking. Cases numbered only four during 1975-1979, more than doubled during 1980- 1984, reached 24 during 1985-1989, and then more than doubled again to 53 during 1990-1994. The Cook County data are consistent with findings elsewhere. After reviewing a large number of adverse medical events among patients admitted to New York hospitals between 1985 and 1988, Leape et al. [25] found that the proportion of adverse events due to negligence was highest (75%) for diagnostic mishaps. Trends showing decreasing numbers of malTABLE 5: Radiology-Related Malpractice Lawsuits, Cook County, IL, 1975-1994: Missed Diagnoses 5-Yr Period Missed Lung Cancer Missed Breast Cancer Missed GI Lesions Missed Bone Disease 1975-1979 13 4 3 102 1980-1984 39 9 9 142 1985-1989 24 24 7 76 1990-1994 32 53 9 59 Downloaded from www.ajronline.org by 2600:1700:3c30:a3d0:f906:a606:b80b:7d98 on 07/20/22 from IP address 2600:1700:3c30:a3d0:f906:a606:b80b:7d98. Copyright ARRS. For personal use only; all rights reserved 786 BERLIN AND BERLIN AJR:165, October 1995 Fig. 4.-Trends in malpractice lawsuits alleging missed radiologic diagnoses of bone disease, breast cancer, lung cancer, and GI lesions, Cook County, IL, 1975-1994. practice claims for bone abnormalities, but increasing claims for missed cancers, have also been documented by others. The American College of Radiology (ACR) Bulletin in 1985 reported that missed fracture or dislocation cases represented 25% of all radiologic malpractice cases nationally and that claims of failure to diagnose cancer was a distant second in frequency, at 8% [26]. A 1987 review by Hamer et al. [27] of 1200 radiologic malpractice cases involving the federal governmentfound that misdiagnosis of cancer had become the most common claim, accounting for 30% of all cases. This finding was confirmed by Dahlen and Foley [28], who added that the proportion of all malpractice lawsuits filed against radiologists and attributed to missed cancer cases grew to 47% between 1985 and 1987. In an analysis of national insurance data, the ACR Bulletin in 1989 reported that missed lesions on chest radiographs and mamrnograms had become the most frequent, and costliest, allegation of malpractice in the radiologic community [29]. These findings have been confirmed more recently [30]. Errors in Medicine and in Radiology Ever since Garland published his first report of nadiologic errors 46 years ago [31], the literature has been replete with a wide variety of studies of error rates. Summarized in depth previously by Berlin, as well as others, all have confirmed Garland’s original data that error rates among radiologists hover in the 30% range [32-34]. That radiologic errors lead to malpractice lawsuits is an obvious conclusion, but the determination of whether radiologic errors actually constitute malpractice is not obvious [32, 35]. A report on lung cancer issued by the Physician Insurers Association of America in 1992 revealed that of all cases where prior chest radiographs were available, retrospective examination revealed the