Spiral CT in the evaluation of flank pain: overall accuracy and feature analysis.
OBJECTIVE
Our goal was to assess test reliability and identify those features that have the strongest positive and negative predictive values in the diagnosis of renal colic using spiral CT.


METHODS
Fifty non-contrast-enhanced CT scans (5 mm slice thickness) obtained in patients presenting with flank pain were reviewed by three radiologists blinded to the final diagnoses. The sensitivity, specificity, and positive and negative predictive values for nine pertinent findings were determined as compared to clinical follow-up.


RESULTS
Twenty-nine cases had findings of ureteral obstruction. Findings with the strongest positive predictive values (> 0.90) were ureteral stone, hydronephrosis, hydroureter, periureteral stranding, and ureterovesical junction edema. Findings with the strongest negative predictive values (> 0.89) were absence of hydronephrosis and hydroureter. The areas under the receiver operating curves for Readers 1, 2, and 3 were 0.970 +/- 0.030, 0.942 +/- 0.036, and 0.982 +/- 0.020.


CONCLUSIONS
Absence of hydroureter and hydronephrosis on spiral CT images should prompt a search for a diagnosis other than an obstructing ureteral stone.
Fielding
J R
JR
Department of Radiology, Brigham and Women's Hospital, Boston, MA 02115, USA.
Fox
L A
LA
Heller
H
H
Seltzer
S E
SE
Tempany
C M
CM
Silverman
S G
SG
Steele
G
G
D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006417:Hematuria / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000000981:diagnostic imaging*; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014570:Urologic Diseases / Q000000981:diagnostic imaging*