Abstract #0068

Chemical Shift Induced Phase Errors in Phase Contrast MRI

Matthew J. Middione¹,², Daniel B. Ennis,²³

¹Department of Radiological Sciences, Diagnostic Cardiovascular Imaging Section , University of California, Los Angeles, CA, United States; ²Biomedical Physics Interdepartmental Program, University of California, Los Angeles, CA, United States; ³Department of Radiological Sciences, Diagnostic Cardiovascular Imaging Section, University of California, Los Angeles, CA, United States

Phase contrast MRI (PC-MRI) is subject to numerous sources of error, which decrease both quantitative accuracy and clinical confidence in the reported measures. Perivascular fat surrounds most vessels and can chemically shift across the vessel wall into the lumen, thereby superposing the complex off-resonant fat signal onto the complex signal in a pixel containing flowing blood. This phase error can lead to a clinically significant over- or underestimation of net forward flow (10-20mL). A judicious choice of bandwidth and TE can reduce the chemical shift induced phase errors in PC-MRI net forward flow measurements to clinically insignificant levels (<5mL).