Usefulness of fat-suppression magnetic resonance imaging for oral and maxillofacial lesions.

In magnetic resonance imaging (MRI) of the oral and maxillofacial region, where large amounts of fat are normally present, the high signal intensity of fat on T1-weighted images (T1WI) and the chemical-shift artifact have limited the utility of paramagnetic contrast agents. Eliminating fat signal by fat-suppression techniques can increase the value of contrast-enhanced MRI. The present study was designed to evaluate the utility and role of chemical-shift imaging for fat suppression in the detection of oral and maxillofacial lesions in 22 patients (17 with malignant tumors, two with benign tumors, and three with inflammation). The depiction of lesions on the postcontrast fat-suppression T1WI was compared with that of conventional pre- and postcontrast T1 and T2WI on a four-grade scale (grades 0-3). The postcontrast fat-suppression T1WI (average grade, 2.86) were significantly superior to the precontrast T1WI (0.82) and postcontrast T1WI (1.86) and T2WI (1.68). Postcontrast fat-suppression T1WI were particularly beneficial in the detection of central necrosis or extracapsular invasion of metastatic neck lymph nodes as well as in defining the lesion extent at fat-containing areas such as the bone marrow or cheek. These findings demonstrated that the fat-suppression technique is extremely useful in the delineation of oral and maxillofacial lesions without increase of the scan time or image postprocessing procedures.