[HST]: possible TIA's, and dizziness with head changes some times  [SAS]: as above   CAROTID DUPLEX ULTRASOUND    COMPARISON: 1/1/00    FINDINGS: Gray scale, color doppler and spectral imaging were  performed.  Images submitted electronically.   RIGHT SIDE: There is moderate amount of mixed plaque in the proximal  internal carotid artery. There is mildly increased peak systolic  velocity system with 50-69% stenosis.  These velocities represent  increased since prior study.  Maximal PSV in the internal carotid is  139 cm/sec. Normal velocities in CCA and ECA.  ICA/CCA ratio is 1.8   There is antegrade flow in the vertebral artery.    LEFT SIDE: There are also mixed plaques in the left bifurcation  extending into the internal carotid artery. There is minimally  elevated velocity in the proximal internal carotid artery consistent  with borderline 50-69% stenosis.  Maximum PSV in the internal carotid  is 133 cm/sec. Normal velocities in CCA and ECA.  ICA/CCA ratio is  1.5  There is antegrade flow in the vertebral artery.       IMPRESSION:    1.  Bilateral mixed plaques right greater than left.  2.  There is minimally elevated peak systolic velocity in both  internal carotid arteries consistent with borderline 50-69% diameter  reduction.     ______________________________________    Electronically signed by:AAAAA B CCCCCC, MD Date: 01/01/1901 Time:13:34