DIFFERENTIATION OF PERIAPICAL GRANULOMAS AND RADICULAR CYSTS BY DIGITAL RADIOMETRIC ANALYSIS

It is generally accepted that two of the most commonly seen radiolucen cies, the periapical granuloma and the radicular cyst, cannot be diffe rentiated radiographically. The purpose of this investigation was to d etermine the feasibility of identifying radiometric differences in the se two pathologic conditions by analyzing the patterns of the gray-lev el distributions of digitized radiographic images. Radiographs used in the study had been sent by practitioners to the School of Dentistry w ith tissue specimens. Radiographs of lesions identified as periapical granulomas and radicular cysts in the mandibular posterior quadrant we re included in the study. The radiographs were digitized and regions o f interest were drawn to include the lesions. Frequency distributions (histogram) with 256 gray-scale intervals and a cumulative percent his togram were computed. The typical histograms of the dental granulomas had narrower ranges and lower gray-scale values than did cysts. The re sults of this study indicate that it is feasible to radiometrically di fferentiate between lesions that are visually indistinguishable on rad iographs.