Multidetector helical CT in the evaluation of acute small bowel obstruction: comparison of non-enhanced (no oral, rectal or IV contrast) and IV enhanced CT.
OBJECTIVE
To compare accuracy of non-enhanced CT (NECT) (no oral or IV contrast) and enhanced CT (ECT) (IV enhanced only) to diagnose small bowel obstruction and evaluate reviewer's experience impact.


METHODS
Ninety-nine adult patients underwent 105 NECT and ECT (6 patients had 2 examinations) on a four-detector CT. An abdominal radiologist, an abdominal imaging fellow, a second-year radiology resident retrospectively reviewed NECTs and ECTs separately and independently blinded to outcome. Discrepancy of diameter of proximal and distal small bowel+/-a transition was considered indication of mechanical bowel obstruction. Reference standard was surgery in 26 and chart review in 79.


RESULTS
Mechanical obstruction was present in 56% (59/105). The average sensitivity, specificity, negative and positive predictive and accuracy values for NECT were 88.1% (CI: 80-96%), 77% (CI: 65-89%), 83.0% (CI: 72-95%), 83% (CI: 74-92%), and 83% (CI: 76-90%) with no significant difference between three reviewers. The corresponding numbers for ECT were 87.6% (CI: 79-96%), 75% (CI: 63-88%), 82.6.0% (CI: 71-94%), 82.1% (CI: 73-92%), and 82% (CI: 75-90%) (p>0.5). Area under curve (AUC) of ROC curves of three reviewers did not show significant statistical difference (p>0.5).


CONCLUSIONS
NECT and ECT have comparable accuracy to diagnose mechanical small bowel obstruction and can be interpreted by reviewers with different levels of expertise.
Department of Medical Imaging, Sunnybrook Health Science Centre, University of Toronto, 2075 Bayview Avenue, Toronto, Ont. M5G 2N2, Canada. mostafa.atri@uhn.on.ca
Mostafa
M
Atri
Caitlin
C
McGregor
Mathew
M
McInnes
Niall
N
Power
Katayoun
K
Rahnavardi
Calvin
C
Law
Alex
A
Kiss
D000285:Administration, Rectal; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D007415:Intestinal Obstruction / Q000000981:diagnostic imaging*; D007421:Intestine, Small / Q000000981:diagnostic imaging*; D007472:Iohexol / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed / Q000379:methods*; D055815:Young Adult
D003287:Contrast Media; D007472:Iohexol