DOS Kongressen 2014 ·
141
Sensitivity and specificity of CT and MRI imaging in
occult hip fractures
Martin Haubro, Camilla Stougaard, Trine Torfing, Søren Overgaard
Department of Orthopaedic Surgery and Traumatology, Odense University
Hospital; Department of Radiology, Odense University Hospital
Background:
The incidence of occult hip fracture has been estimated to 2-10%
using standard X-ray imaging. It has been stated that MRI is superior to CT in
detecting occult fracture of the hip however this statement is based on case
reports and non-controlled studies of few patients.
Purpose / Aim of Study:
To estimate sensitivity and specificity of CT and MRI
examinations in patients with fractures of the proximal femur. To determine the
interobserver agreement of the modalities among a senior consulting radiolo-
gist, a resident in radiology and a resident in orthopaedics surgery.
Materials and Methods:
67 patients seen in the emergency room with hip
pain after fall, inability to stand and a primary X-ray without fracture were eval-
uated with both CT and MRI. The images were analysed by a senior consulting
musculoskeletal radiologist, a resident in radiology and a resident in orthopae-
dic surgery. Sensitivity and specificity were estimated with MRI as the golden
standard. Kappa value was used to assess level of agreement in both MRI and
CT finding.
Findings / Results:
15 fractures of the proximal femur were found. Two frac-
tures were not identified by CT and four changed fracture location. Among
those, three patients underwent surgery. Sensitivity of CT was 0.87; 95% CI
[0.60;0.98]. Kappa for interobserver agreement for CT were 0.46; 95% CI
[0.23; 0.76] and 0.67; 95% CI [0.42; 0.90]. For MRI 0.67; 95% CI [0.43;0.91]
and 0.69; 95% CI [0.45;0.92].
Conclusions:
MRI was observed to have a higher diagnostic accuracy than CT
in detecting occult fractures of the hip. Interobserver analysis showed high kap-
pa values corresponding substantial agreement in both CT and MRI.
88.
