| Normal |
Mid graft PSV > 150 cm/sec |
No visible narrowing |
| Distended outflow veins |
| Anastamosis PSV > 300 cm/sec, chaotic, disorganized flow |
Aneurysms, puncture sites, perigraft |
| fluid may be visible |
|
| Moderate stenosis |
Ratio of PSV at stenosis to PSV at 2 cm |
Decrease in lumen diameter |
| beyond anastamosis if normal-appearing <3 |
Echogenic narrowing |
| Wall abnormalities |
|
| Severe stenosis |
Marked velocity acceleration at stenotic area |
Intraluminal echogenicity < 2 mm |
| lumen >50% diameter reduction |
| Ratio of PSV at stenosis to PSV at 2 cm |
Marked reduction in lumen |
| beyond anastamosis if normal-appearing >3 |
diameter with color doppler |
|
| Inflow Stenosis |
Peak systolic velocities will increase at the site of |
Intraluminal echogenicity |
| stenosis with monophasic and diminished |
< 2 mm lumen at velocity acceleration |
| waveforms distal |
| Flow acceleration with graft compression at |
| outflow anastamosis |
|
| Outflow stenosis |
Mid graft PSV < 100 cm/s |
Intraluminal echogenicity |
| Distal vein > 300 cm/sec |
< 2 mm lumen velocity acceleration |
| Velocity at the proximal anastamosis will diminish |
Prominent collateral veins around outflow |
| in proportion to severity of venous outflow stenosis |
|
| Occlusion |
No doppler signal |
Intraluminal echogenicity |
| Graft walls appear collapsed |
| Occluded vein may not be visible |
