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DOS Kongressen 2016 ·
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Agreement and reliability of acetabular Bone
Mineral Density measurements in total hip
arthroplasty using Single and Dual energy
computed tomography with 3-dimensional segmentation
Bo Mussmann, Søren Overgaard, Trine Torfing, Morten Bøgehøj, Oke Gerke, Poul
Erik Andersen
Department of Radiology, Odense University Hospital; Department of Orthopedic
Surgery and Traumatology, Odense University Hospital; Department of Radiology,
Odense University Hospital; Department of Orthopedic Surgery and Traumatology,
Odense University Hospital; Department of Nuclear Medicine, Odense University
Hospital; Department of Radiology, Odense University Hospital
Background:
Periprosthetic bone loss is considered a predictor of aseptic loosening of
the acetabular component in total hip arthroplasty. However, no studies have shown this
association. This may be explained by imaging methods used. Dual energy CT (DECT) has
previously shown better delineation of the interface between bone and prosthesis and
may be beneficial in quantitative analysis of bone loss close to the implant as compared
to single energy computed tomography (SECT).
Purpose / Aim of Study:
To test the agreement and reliability of bone mineral density
measurements (BMD) in close proximity of the acetabular cup using SECT and DECT im-
ages and 3D segmentation software.
Materials and Methods:
12 un-cemented and 12 cemented cups were inserted in por-
cine hip specimens ex vivo. A femoral stem was attached to each specimen and imag-
ing was performed with SECT and DECT. The specimens were repositioned and scans
repeated to obtain double measurements. For each scan BMD was measured in a hemi-
spherical volume around the acetabular cup using in-house segmentation software.
Findings / Results:
In the uncemented concept mean BMD difference between the dou-
ble measurements in SECT was 8 mg/cm3 (p=0.64) and 2 mg/cm3 in DECT (p=0.596).
ICC was 0.90 for SECT and 0.91 for DECT. In the cemented concept the differences were
41 mg/cm3 (p=0.055) and 11 mg/cm3 (p=0.013), respectively, and ICC was 0.74 for
SECT and 0.91 for DECT. In both concepts the Bland Altman limits of agreement were
wider in SECT (uncemented: -95 to 111; cemented: -107 to 189) compared with DECT
(uncemented: -28 to 23; cemented: -20 to 42).
Conclusions:
There were no statistically significant reliability differences between SECT
and DECT, but results suggest that the agreement of DECT is better than SECT, and both
scan modes perform better in the un-cemented concept compared with the cemented
concept.
No conflicts of interest reported
148.