Diffusion-weighted Magnetic Resonance Imaging in Odontogenic Keratocysts: Preliminary Study on Usefulness of Apparent Diffusion Coefficient Maps for Characterization of Normal Structures and Lesions.

Abstract

To investigate the usefulness of diffusion-weighted magnetic resonance imaging (DWI) in odontogenic keratocysts, especially apparent diffusion coefficient (ADC) maps for the characterisation of normal structures and cystic lesions in the jaw. Sixteen patients who underwent magnetic resonance imaging (MRI) for the diagnosis of a cystic lesion in the jaw were included in this prospective study. DWI was performed on a 1.5 T unit with b factor of 0 and 800 s/mm2, and ADC maps were generated. ADC values were measured for the normal structures in the upper neck area and for the cystic lesion in the jaw. The mean ADC value of the cerebrospinal fluid (3.66 ± 0.47 × 10-3 mm2/s) in the upper neck area was higher than that of the nasal mucosa (1.80 ± 0.19 × 10-3 mm2/s), Waldeyer's ring (0.75 ± 0.11 × 10-3 mm2/s) and the spinal cord (0.71 ± 0.20 × 10-3 mm2/s). The mean ADC value of the five odontogenic keratocysts (1.03 ± 0.31 × 10-3 mm2/s) was lower than that of the one simple bone cyst (2.79 × 10-3 mm2/s), three nasopalatine duct cysts (2.28 ± 0.12 × 10-3 mm2/s), three radicular cysts (1.82 ± 0.71 × 10-3 mm2/s) and four dentigerous cysts (1.67 ± 1.06 × 10-3 mm2/s). This study suggested the usefulness of DWI in odontogenic keratocysts, especially ADC maps for the characterization of normal structures and cystic lesions in the jaw.