AIM To examine the improvement in the visualisation of bladder and ureteric pathologies
next to a hip prosthesis with metallic artefact reduction for orthopaedic implants
(O-MAR) MATERIALS AND METHOD Thirty-four patients who underwent pelvic computed tomography
(CT) for non-prosthesis-related causes were enrolled retrospectively. Portal venous
phase scans were reconstructed both with standard iterative reconstruction (ITR) and
with O-MAR. The density of the ureters and the bladder was measured at both sides
in the plane of the prosthesis. A semi-quantitative score was also used to assess
visibility. The R (version 3.4.1) package was used for statistical analysis RESULTS
The average (μ) density of the 41 prosthesis side ureters was significantly lower
on ITR images (μ=–94.76±150.48 [±SD] HU) than on O-MAR images (μ=–13.40±36.37 HU;
p<0.0004). The difference between the ITR and O-MAR (μ=–138.62±182.64 versus –35.55±40.21
HU; p<0.0003) was also significant at the prosthesis side of the bladder. The visibility
of the prosthesis side ureters was improved: 53.7% was obscured on ITR series compared
to 4.9% on O-MAR. The visibility score was also better across all levels (p<0.001)
with O-MAR. In four cases (13%), the O-MAR images significantly changed the diagnosis:
in two cases ureteric stones, in one case each a bladder stone and a bladder tumour
were discovered CONCLUSIONS O-MAR reconstruction of CT images significantly improves
the visibility of the urinary tract adjacent to metallic hip implants. Thus, O-MAR
is essential for detecting ureteric and bladder pathologies in patients with a hip
prosthesis
