Diffusion-weighted magnetic resonance imaging in the characterization of odontogenic cysts and tumors.

OBJECTIVES

The aim of this study was to evaluate diffusion-weighted imaging (DWI) in comparison with morphologic magnetic resonance imaging (MRI) in differentiating among odontogenic keratocyst (OKC), unicystic ameloblastoma (UAB), and dentigerous cyst (DC).

STUDY DESIGN

Contrast-enhanced MRI, including DWI, was performed on 27 patients with the 3 lesions. Signal intensity characteristics were evaluated on T1- and T2-weighted MRI. The apparent diffusion coefficient (ADC) cutoff value to most effectively differentiate among the 3 lesions was calculated with receiver operating characteristic analysis.

RESULTS

In total, 17 OKCs, 5 UABs, and 5 DCs were diagnosed histologically. There were no significant differences among them in signal intensity on T1- or T2-weighted images (P ≥ .13). On DWI, 14 of 17 OKCs showed restricted diffusion with a mean ADC value of 0.954 × 10 mm/s. All 5 UABs and all 5 DCs exhibited facilitated diffusion with ADC values ≥ 2.150 × 10 mm/s. The ADC cutoff to differentiate OKCs from UABs was 2.137 × 10 mm/s (P = .01); UABs from DCs was 2.422 × 10 mm/s (P = .03); and OKCs from DCs was 2.347 × 10 mm/s (P = .01).

CONCLUSIONS

Addition of diffusion-weighted sequences to MRI jaw protocols can assist in the characterization of OKCs, UABs, and DCs.