Apparent diffusion coefficient-based differentiation of cystic lesions of the mandible

Abstract

To evaluate the apparent diffusion coefficient (ADC) for differentiation of cystic lesions of the mandible. We retrospectively evaluated 27 cystic lesions of the mandible. We determined the overall ADCs and the pixel-based ADC profiles (ADC mapping) of the fluid areas using two b values (500 and 1000 s/mm2). The overall ADCs of the fluid areas of ameloblastomas (2.45 ± 0.27 × 10−3 mm2/s) and simple bone cysts (2.52 ± 0.14 × 10−3 mm2/s) were significantly larger than those of dentigerous cysts (1.50 ± 0.49 × 10−3 mm2/s; p = 0.047 and p = 0.041, respectively), radicular cysts (0.90 ± 0.21 × 10−3 mm2/s; p = 0.048 and p = 0.042, respectively), and keratocystic odontogenic tumors (0.87 ± 0.13 × 10−3 mm2/s; p = 0.032 and p = 0.021, respectively). However, the overall ADCs were similar between ameloblastomas and simple bone cysts and among dentigerous cysts, radicular cysts, and keratocystic odontogenic tumors. ADC mapping demonstrated that ameloblastomas and simple bone cysts had 80–99 % fluid areas with high ADC levels, whereas radicular cysts and keratocystic odontogenic tumors had 66–100 % fluid areas with low or extremely low ADC levels. However, the ADC mapping profiles of dentigerous cysts differed substantially among the cases. The ADC-based criteria did not effectively differentiate between ameloblastomas and simple bone cysts or between radicular cysts and keratocystic odontogenic tumors. The ADC-based differentiation was effective for discriminating some types of cystic lesion of the mandible.