The frequency and nature of incidental findings in cone-beam computed tomographic scans of the head and neck region: a systematic review.

BACKGROUND: The authors analyzed the literature critically to determine the frequency and nature of incidental findings (IFs) in cone-beam computed tomographic (CBCT) scans of the head and neck region. TYPES OF STUDIES REVIEWED: The authors conducted a systematic search of several electronic databases (MEDLINE, Embase, PubMed, Scopus, Web of Science, the Cochrane Library) through July 14, 2012, as well as a limited gray-literature search (in Google Scholar). Inclusion criteria encompassed the frequency of reports of IFs in the head and neck region in CBCT imaging, regardless of the sample origin. The authors used no search limitations. They evaluated methodological quality according to 15 criteria related to study design, population characteristics and statistical analysis.
RESULTS: Initially, the authors identified 66 articles from the electronic database searches and another one via the gray-literature search. Once they applied the final selection criteria, they found that only five articles satisfied the inclusion criteria. In articles in which investigators reported the number of IFs as the absolute number of IFs detected, the frequency ranged from 1.3 to 2.9 IFs per CBCT scan. Conversely, in articles in which authors reported the number of IFs as the number of scans containing IFs, the frequency ranged from 24.6 to 93.4 percent of CBCT scans. Methodological quality averaged 77.2 percent (range, 60-93 percent) of the maximum possible score. CONCLUSIONS AND CLINICAL IMPLICATIONS: IFs are detected relatively frequently in CBCT imaging, and considerable variation is evident in their frequency and nature. The majority are extragnathic findings (that is, those found outside the region of the dentition and alveolus), thus emphasizing the need for complete and proper review of the entire image, regardless of field of view or region of interest.