Ureterolithiasis: can clinical outcome be predicted with unenhanced helical CT?
OBJECTIVE
To evaluate the use of helical computed tomography (CT) without contrast material enhancement for prediction of a favorable outcome in ureterolithiasis.


METHODS
CT studies were reviewed in 69 patients with a single ureteral stone not located at the ureteropelvic junction. CT findings (tissue rim sign, hydronephrosis, perinephric fat stranding, perinephric fluid collections, and thickening of renal fascia) were graded on a scale of 0-3. Stone diameter and renal parenchymal enlargement were also measured.


RESULTS
Twenty-two patients had spontaneous passage, 12 did not respond to conservative treatment, and 35 were lost to follow-up. When the latter 35 patients were excluded, perinephric fat stranding (P = .044) and perinephric fluid collections (P = .021) were graded significantly higher in patients with spontaneous stone passage. Mean stone diameter was significantly larger (P < .001) in patients in whom conservative treatment failed (mean, 7.8 mm) than in patients with spontaneous stone passage (mean, 2.9 mm). The presence of a tissue rim sign and the grade of hydronephrosis, renal fascial thickening, and renal parenchymal enlargement were not significantly different between the two groups.


CONCLUSIONS
In addition to stone size, the degree of perinephric fat stranding and the presence of perinephric fluid collections are useful ancillary signs for help in predicting the likelihood of stone passage.
Takahashi
N
N
Department of Radiology, Lyndon B. Johnson General Hospital, Houston, TX 77026, USA.
Kawashima
A
A
Ernst
R D
RD
Boridy
I C
IC
Goldman
S M
SM
Benson
G S
GS
Sandler
C M
CM
D000273:Adipose Tissue / Q000000981:diagnostic imaging; D000293:Adolescent; D000328:Adult; D005069:Evaluation Studies as Topic; D005122:Exudates and Transudates; D005205:Fascia / Q000000981:diagnostic imaging; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D006869:Hydronephrosis / Q000000981:diagnostic imaging; D007091:Image Processing, Computer-Assisted; D007668:Kidney / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011856:Radiographic Image Enhancement; D012075:Remission, Spontaneous; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome; D014514:Ureteral Calculi / Q000000981:diagnostic imaging* / Q000628:therapy