Description

Takahashi et al used unenhanced helical CT scans to identify factors associated with passage of ureteral stones. This can help identify a patient who can be managed conservatively. The authors are from Lyndon B. Johnson General Hospital and the University of Texas Houston.


 

Parameters:

(1) diameter of stone in mm

(2) perinephric fat stranding (linear areas of soft tissue attenuation in the perinephric space)

(3) perinephric fluid collection (discrete areas of fluid attenuation in the perinephric space)

(4) location in the ureter

 

Parameter

Finding

Grade

perinephric fat stranding

none

0

 

mild (few thin strands)

1

 

moderate

2

 

marked (many thick strands)

3

perinephric fluid collection

none

0

 

1 or 2 small (< 1 cm)

1

 

more than 3 small or less than 3 large

2

 

3 or more large (>= 1 cm)

3

 

 

Parameter

Likely to Pass

Indeterminate

Unlikely to Pass

Stone Size

<= 3 mm

3.1 - 7.0 mm

> 7.0 mm

Fat Stranding

Grade 3

Grade 2

Grade 0 or 1

Fluid Collection

Grade 2 or 3

Grade 1

Grade 0

Location

distal

mid or proximal

ureteropelvic junction

 


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