FAT-SUPPRESSION FAILURE ARTIFACTS SIMULATING PATHOLOGY ON FREQUENCY-SELECTIVE FAT-SUPPRESSION MR IMAGES OF THE HEAD AND NECK

Purpose: To describe fat-suppression failure artifacts and to caution against their misinterpretation. Method: Magnetic-susceptibility artifacts were studied in a phantom model and the results were compared to MR images obtained in clinical cases. Findings: Artifacts manifested themselves as regions of focal fat-suppression failure and appeared as bright signals without geometric distortions at magnetic-susceptibility interfaces along the static field (z) direction. The location and extent of these artifacts were independent of either frequency or phase-encoding direction and are different from those observed in gradient-echo images. Conclusion: In representative clinical MR exams, these artifacts were identified in the high nasopharynx and low orbit and should not be misinterpreted as pathology.