Parameters:
(1) diameter of narrow portion of the left renal vein in mm
(2) diameter of dilated portion of the left renal vein in mm
(3) diameter of the right renal vein in mm
(4) diameter of the abdominal aorta in mm
D/N ratio = ratio of the dilated to narrow portion of the left renal vein =
= (diameter of dilated left renal vein segment in mm) / (diameter of narrow segment in mm)
D/A ratio = ratio of the dilated segment of the left renal vein to the aorta =
= (diameter of the dilated left renal vein segment in mm) / (diameter of the abdominal aorta in mm)
RVD = difference in diameter of left and right renal veins in mm = renal vein difference =
= (diameter of the dilated segment of left renal vein in mm) – (diameter of the right renal vein in mm)
|
Measurement
|
Result
|
Points
|
|
D/N ratio
|
> 3.7
|
1
|
|
|
<= 3.7
|
0
|
|
D/A ratio
|
> 0.75
|
1
|
|
|
<= 0.75
|
0
|
|
RVD
|
> 1.7 mm
|
1
|
|
|
<= 1.7 mm
|
0
|
number of ultrasound parameters present =
= SUM(points for the 3 measurements)
Interpretation:
• minimum number: 0
• maximum number: 3
• A number >= 2 indicates the presence of the nutcracker syndrome.
• The differential diagnosis includes the nutcracker phenomenon, which is an asymptomatic anatomic finding.
