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Renal Artery Duplex Examination Renal Artery Exam Renal Arteries

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Renal Artery Duplex Examination Renal Artery Exam Renal Arteries Powered By Docstoc
					             Renal Artery Duplex
                Examination

         M. Robert De Jong, Jr., RDMS, RDCS, RVT, FSDMS
              Radiology Technical Manager, Ultrasound
         The Russell H. Morgan Department of Radiology and
                        Radiological Science
               The Johns Hopkins Medical Institutions
                        Baltimore, Maryland




              Renal Artery Exam
• Review of anatomy
• Protocols
• Diagnostic Criteria




                    Renal Arteries
•   First lateral branch off of
    aorta
     – Directed over crus of
       diaphragm
     – Form a right angle with
       aorta
•   Originate just distal to origin
    of SMA
•   Right renal artery passes
    underneath the IVC
•   Left more superior in location
•   Renal veins are anterior to
    arteries
            Renal Arterial Anatomy
    • At hilum the main
      renal artery divides
      into anterior and
      posterior segmental
      arteries
    • Segmental arteries
      become the
      interlobar arteries
       – Course alongside the
         renal pyramids




            Renal Arterial Anatomy
•   Interlobar arteries branch
    into arcuate arteries at
    corticomedullary junction
•   Arcuate arteries travel
    across the top of renal
    pyramids and give rise to
    interlobular arteries
     – Tiny parenchymal branches
       that course toward the
       kidney surface




            Renal Arterial Anatomy
    • Intrarenal arterial
      anatomy
       –   Segmental
       –   Interlobar
       –   Arcuate
       –   Interlobular
                           Protocols
  • Based on standards and scanning
    guidelines of ultrasound societies and
    accrediting organizations




                       Renal Duplex
  • Gray Scale
      – Longitudinal
          • Medial
          • Midline
          • Lateral
      – Transverse
          • Up
          • Mid
          • Low
      – Kidneys
          • Length
              + 9 -12 cm
          • Echogenicity
          • Pathology




                       Renal Duplex
• Color
                                  • Power
  –   Renal perfusion
  –   Locating vessels              – Renal perfusion
  –   Angle correction guidance     – Origin of arteries
  –   Locate areas of aliasing         • Less angle dependent
      Power Doppler of Origin of
         Right Renal Artery




                Spectral Doppler
• Angle corrected and            • Acceleration Time and /
  peak velocity measured           or Index measured
   – Aorta                          – Intrarenal
      • Level of Renal Artery
                                        • Upper
      • Distal to SMA
                                        • Mid
   – Renal Artery
                                        • Lower
      • Origin / Proximal
             + Atherosclerotic   • Renal Vein
      • Mid
             + FMD
      • Distal
      • Track entire vessel
        looking for highest
        velocity




 Track Entire Length of Artery
           Intrarenal Signals




            Main Renal Vein




   Direct Diagnostic Criteria
• > 60% stenosis:
  – PSV 180-200cm/sec
  – RAR 3-3.5

  – House - AJR;1999:761
  – Hua - Ann Vasc Surg 2000;14:118
              RAS: Peak 290 cm/sec
                Aorta: 80 cm/sec
                    RAR: 3.6




   Indirect Diagnostic Criteria
• RAS 60% or greater
  – Acceleration time >0.07s
  – Acceleration Index < 3 m/sec2

  – Stavros and al - Radiology;1992:184 487




    RAS Indirect Evaluation
• Intra-renal waveform
  pattern
• Large sharply
  defined waveforms
  – Posterior lateral
    scanning
  – Use segmental
    arteries
  – Get kidney close to
    transducer

                                              Courtesy L. Scoutt, MD
      RAS Indirect Evaluation
AI - slope of line from
  onset of systole to
  early systolic peak
  complex (m/sec)
AT - length of time
  from onset of systole
  to early systolic
  peak complex


                          Courtesy L. Scoutt, MD




           Normal AI and AT




     RAS on left. AT > 105 ms
   How We Use Both Criteria
• Direct
   – See area of stenosis
• Indirect
   – Portable exams
   – Technically limited exams
   – Compare upper, mid, and lower poles
      • If all normal
           + Probably not a hemodynamically significant stenosis
           + If one area is abnormal
                » Look for stenotic accessory or segmental artery




                     Conclusion
• Take Home
   – Know your anatomy
   – Understand importance of patient prep
   – Follow protocol
   – Know diagnostic criteria




                     Thank You

				
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