- To determine the growth rate, methodologic clarity, and quality changes in cost-effectiveness analyses (CEAs) and to assess whether the U.S. Panel on Cost-effectiveness in Health and Medicine recommendations affected CEA studies in which imaging technologies were evaluated. Six databases were systematically searched for CEA reports published between 1985 and 2005. All imaging-related studies were selected and grouped according to year, country, and journal of publication, as well as imaging modality and disease being studied. Two readers with formal training in decision analysis and CEA used a seven-point (1, low; 7, high) Likert scale based on reasonableness of assumptions, quality of presentation, and adherence to guidelines to independently evaluate study quality. Quality scores according to year, country, and journal of publication were compared with the unpaired Student t test. The first radiology-related CEA was published in 1985; 111 radiology-related CEAs were published between 1985 and 2005. The average number of studies increased from 1.6 per year between 1985 and 1995 to 9.4 per year between 1996 and 2005. Eighty-six studies were performed to evaluate diagnostic imaging technologies, and 25 were performed to evaluate interventional imaging technologies. Ultrasonography (35.0%), angiography (31.5%), magnetic resonance imaging (22.5%), and computed tomography (19.8%) were evaluated most frequently. Forty-nine studies received government funds; 42 did not disclose the source of funding. The mean quality score was 4.23 +/- 1.12 (standard deviation), without significant improvement over time. Scores in studies performed in the United States were significantly higher than scores in studies that were not performed in the United States (4.45 +/- 1.02 vs 3.61 +/- 1.17, respectively; P < .01). Scores were also higher in journals with three or more CEA articles published during the study period than in journals with two or fewer CEA articles published during this period (4.54 +/- 1.09 vs 3.91 +/- 1.06, respectively; P < .01). CEAs are an important tool with which to analyze the value of diagnostic imaging. However, improvement in the quality of analyses is needed. http://radiology.rsnajnls.org/cgi/content/full/249/3/917/DC1.