Diffusion-Weighted Imaging in the Oral and Maxillofacial Region: Usefulness of Apparent Diffusion Coefficient Maps and Maximum Intensity Projection for Characterization of Normal Structures and Lesions

The aim of this study was to investigate diffusion-weighted imaging (DWI) in the oral and maxillofacial region, with a special focus on the usefulness of apparent diffusion coefficient (ADC) maps and maximum intensity projection (MIP) for characterization of normal structures and lesions.

Thirty-five patients who underwent magnetic resonance imaging (MRI) for diagnosis of oral and maxillofacial lesions were included in this prospective study. DWI was performed on a 1.5 T unit, with b factor of 0 and 800 s/mm²; moreover, ADC maps were generated. ADC values were measured for normal structures, odontogenic infections, squamous cell carcinomas (SCC), and hemangiomas.

As regards the normal structures, the mean ADC value of the cerebrospinal fluid (3.65±0.60×10^-3 mm²/s) in the upper neck area was higher than that of the spinal cord (0.74±0.15×10^-3 mm²/s, P=0.000), lymph nodes (0.87±0.17×10^-3 mm²/s, P=0.000), and Waldeyer's ring (0.92±0.29×10^-3 mm²/s, P=0.000). The mean ADC value of hemangiomas (1.52±0.31×10^-3 mm²/s) was higher than that of odontogenic infections (0.85±0.36×10^-3 mm²/s, P=0.034) and SCC (1.38±0.22×10^-3 mm²/s, P=0.840). Furthermore, MIP (DWI) showed the normal structures and lesions in the oral and maxillofacial region in an improved way.

DWI, ADC maps, and MIP can be used to characterize and differentiate normal structures and lesions in the oral and maxillofacial region.