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. CONCLUSIONS In representative clinical MR exams, these artifacts were identified in the high nasopharynx and low orbit and should not be misinterpreted as pathology.