RENAL AND TESTICULAR DOPPLER

DR SHARIQ A SHAHMODERATOR: PROF MANJEET SINGH

Doppler Physics

∆F = (FR - FT ) = 2 . FT . VcosƟ/C

SIGNAL PROCESSING AND DISPLAY

POWER DOPPLER

Renal Vascular Doppler Ultrasound

ARTERIAL ANATOMY

VENOUS ANATOMY

VARIANTS

RETRO AORTIC CIRCUM AORTIC

Renal Failure and Obstruction

• Differentiation of an acutely obstructed high-pressure system versus that of a low-pressure, chronically dilated system.

1) RESISTIVE INDEX : Difference of > 0.12) Look for Ureteral Jets

RENAL INFECTION

• Demonstration of altered blood flow, with reduction of Doppler indices and perfusion in

an affected renal segment adds confidence to the diagnosis of focal pyelonephritis.

Nephrolithiasis

Renal TumoursRENAL TUMOURS

RAS/HYPERTENSION

Normal parenchymal vasculature In Color Doppler and power Doppler sonograms

NORMAL RENAL ARTERY DOPPLER INDICES

Index RangePulsatility index (PI) 0.7-1.4

Resistive index (RI) 0.56-0.7

Peak systolic velocity (PSV) 60-140 cm/s

Diastolic/Systolic ratio (D/S) 0.26-0.4

Renal artery/Aorta ratio (RAR) <3.5

Acceleration index 250-380 cm/s2

Time to maximum systole (TMS) 42-57 ms

Normal Doppler waveforms obtained from the main Renal artery . A low resistance waveform with sharp systolic upstroke is expected in the normal main renal artery

Normal Renal Artery waveform showing sharp systolic upstroke and forward flow throughout the cardiac cycle

Normal Doppler waveforms obtained from segmental renal artery.

Normal acceleration time (58msec), the slope from the beginning of the systole to the early systolic peak, of the intrarenal artery

INCIDENCE• . The incidence is less than 1% of cases of mild

to moderate HTN.• However, it rises to 10 to 45 % in patients

with acute (or superimposed upon a preexisting elevation in blood pressure), severe, or refractory hypertension

• 23% of malignant hypertension is the result of renovascular causes

CAUSESMajor causes of the renal arterial stenosis are:• Atherosclerosis 70-90%• Fibromuscular dysplasia 10-20%• Other less common causes of RAS include: Vasculitis (Takayasu’s arteritis) Dissection of the renal artery. Thromboembolic disease Renal artery aneurysm Renal artery coarctation Extrinsic compression Radiation injury

• There are two main methods for sonographic detection of RAS:

1. Direct demonstration of RAS and

2. Indirect assessment of the downstream effect of the stenosis on the segmental renal arteries

DOPPLER PARAMETERS FOR DIAGNOSIS

RA/AO=3.72

PARVUS TARDUS IN SEGEMENTAL ARTERY

Normal and abnormal waveform patterns from segmental renal arteries. Column A shows a range of normal waveforms Column B shows a range of abnormal waveforms with increasing levels of renal artery stenosis from top to bottom

A B

RENAL ARTERY THROMBOSIS

RENAL ARTERY ANEURYSM

Renal Vein Thrombosis