PREPONTINE ARTIFACTS DUE TO PULSATION OF CEREBROSPINAL-FLUID IN T2-WEIGHTED CORONAL MRI - CLINICAL RELEVANCE, INCIDENCE AND A TECHNIQUE FOR EFFICIENT ARTIFACT SUPPRESSION

Coronal T2-weighted MRI is the most sensitive imaging modality to detect temporal lobe pathology. However, prepontine artifacts resulting from pulsation of cerebrospinal fluid occasionally simulate temporal lobe lesions. To characterise this artifact we studied 30 patients without temporal lobe pathology in conventional T2-weighted spin-echo technique (0.5 T, SE 1600/70, coronal, horizontal phase encoding). Visual analysis revealed high-intensity artifacts simulating a lesion in five of 30 cases. The present study shows that prepontine artifacts due to pulsation of cerebrospinal fluid are quite frequent (17 %) and that these artifacts may result in misinterpretation in the evaluation of temporal lobe epilepsy. By a repeat examination in identical methodology while using vertical phase encoding, all artifacts could be identified and an artifact-free representation of the temporal lobes was achieved.