What Do We Know? Disclosure Statement: 3/11/2015. Deep abdominal imaging

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1 Marsha M. Neumyer, BS, RVT, FSVU, FSDMS, FAIUM International Director Vascular Diagnostic Educational Services Vascular Resource Associates Harrisburg, PA Disclosure Statement: CME Calendar QR Code Marsha Neumyer, BS, RVT, FSVU, FSDMS, FAIUM has identified the following potential conflicts of interest: Speaker for Unetixs Vascular, Inc. and Gulfcoast Ultrasound, Inc. Independent Consultant for Pegasus Lectures All other persons involved in this CME Activity do not have any financial relationships with any commercial interest related to the content of this activity. This activity has not received any commercial support. What Do We Know? Deep abdominal imaging Increased attenuation Decreased resolution High-end ultrasound system Low frequency pulsed Doppler 1

2 Abdominal Sonography: Instrumentation Anatomy Arise from lateral aortic wall Level of 1 st or 2 nd lumbar vertebrae Left - more proximal than right Right posterior to IVC 20% -more than one renal artery on each side Branches to adrenal glands and ureters Poorly collateralized organs Renal Arteries 2

3 Pitfalls: Anatomic Factors Variability in location of left renal vein Retro-aortic Bifid o Right renal artery may be anterior to IVC Accessory and multiple renal arteries > 20% of patients Pitfalls: Anatomic Factors Horseshoe kidney Many renal arteries and veins Tortuous renal arteries Color Doppler Power Doppler 3D imaging VDES 2015 Single renal arteries Multiple renal arteries 3

4 Abdominal Arterial Assessment Pitfalls - Patient Related Factors Body habitus (obesity) Poor preparation Overnight fast AM meds with sips of water; no dairy foods No smoking or chewing gum Inability to control respiratory patterns Recent surgery Ascites Pathology Pathology Renal Artery Duplex Imaging Proximal atherosclerosis Orificial atherosclerosis Fibromuscular dysplasia Aneurysms Accessory and multiple renal arteries Parenchymal disease 4

5 Normal Appearance Orificial Atherosclerosis Renal Artery Duplex Imaging Proximal Stenosis 5

6 Renal Artery Duplex Imaging Fibromuscular Dysplasia Nonatherosclerotic Medium-sized arteries Predominantly women Most often bilateral Carotid and renal arteries affected equally Medial Fibromuscular Dysplasia Renal Fibromuscular Dysplasia 6

7 Renal Vein Thrombosis Technical Applications Renal Artery Duplex Imaging Technique Center stream aortic velocity at level of the celiac artery Identify the left renal vein Sweep Doppler throughout ostium and length of the renal artery Acquire spectra from the renal parenchyma Measure length of the kidney 7

8 Renal Artery Duplex Imaging Aortic Velocity Identify left renal vein Renal Artery Duplex Imaging Proximal right renal artery Transition Signal Mid-to-Distal Renal Artery 8

9 Diagnostic Criteria Renal-Aortic Velocity Ratio(RAR) Normal to Mild Stenosis: RAR is < 3.5 PSV is < 180 cm/sec No post-stenotic signal Note: The RAR is valid only when the Aortic PSV is between 40 cm/sec and 100 cm/sec Renal-Aortic Velocity Ratio(RAR) and Other Criteria Renal Artery Stenosis (> 60%): RAR is > 3.5 PSV is > 180 cm/sec Poststenotic turbulence 9

10 Renal-Aortic Velocity Ratio(RAR) and Other Criteria Stenosis that is not yet flow reducing (<60%): RAR < 3.5 PSV > 180 cm/sec NO poststenotic signal Renal Artery Occlusion No flow in an imaged artery Spectral Doppler Color Doppler Power Doppler Small kidney - < 9cm in length Low amplitude, low velocity parenchymal signals Renal Parenchymal Studies Diastolic flow component defines level of renovascular resistance 10

11 Renal Vein Thrombosis Normal Parenchymal Flow Reversed Blunted Diastolic Flow Indirect Renal Hilar Assessment Theory Indirect Renal Hilar Studies There should be delay in systolic upstroke distal to a flow-reducing renal artery stenosis Therefore, we only need to evaluate the distal renal artery or its segmental branches 11

12 Indirect Renal Studies Acceleration Time Acceleration Index Early systolic peak (ESP) Indirect Renal Studies 2 Types of Waveforms 60-79% Stenosis ESP absent AT/AI normal >80% or Occlusion ESP absent AT/AI abnormal Indirect Renal Studies Same patient Same kidney Same day 12

13 Indirect Renal Studies Limitations No anatomic information Cannot differentiate occlusion from severe stenosis May normalize with concomitant parenchymal disease Influenced by renal PSV Know the anatomy Know the pathology Summary Know the examination technique Know the pitfalls Know the solutions 13