Aims and objectives
Background
CT is undoubtedly the most widely-used technique for investigating the skeleton,
basically due to the short scan times and the possibility of 2D and 3D reconstructions.
Nevertheless,
CT diagnostic capabilities are drammatically reduced when a metallic orthopedic implant is present in the field of view [1].
Such metal objects originate artifacts from quantum noise,
beam hardening and scattered radiation [2-4] that markedly reduce the tissue contrast and impair the proper visualization of the implant itself,
of the implant–bone interface and of the surrounding soft...
Methods and materials
Study population
Thirty internal metallic implants in 20 consecutive cadavers (9 males and 11 females,
mean age 74 ± 15 years,
range 43–92 years) submitted to forensic investigation,
including post mortem CT examination,
were examined in the study (Table 1).
Inclusion criterium was: presence of one or more implanted metal device.
Exclusion criteria: cases with major alterations of the soft tissue in proximity of the implant,
for example those caused by putrefaction and lacerations.
CT data acquisition
All examinations were performed on a Dual Source...
Results
Both inter-reader (qualitative analysis) and intra-reader agreement (quantitative analysis) showed excellent resuts (k 0.948; p < 0.001 andICC 0.983; 95%CI = 0.981–0.986,
respectively).
The results of qualitative and quantitative analysis can be summarized as follows:
1.OPTkeV values within each group were found effectively to be the optimal settings for qualitatively reducing metallic artifacts in all the three groups if compared with other monoenergetic reconstructions and SECT images (Figure 3) (Table 3,
4 and 5).
The OPTkeV images of 5.0 mGy acquisitions provided percentages of images...
Conclusion
In conclusion,
although further studies with larger and more homogeneous study population are needed to verify our results,
this study shows that in the presence of metallic orthopedic implants,
DECT and its monoenergetic reconstructions permit a reduction of metal artifacts to be obtained at neutral and low-dose examinations and that these results are better than SECT performed at reduced or even neutral doses
Personal information
For any queries please referr to Laura Filograna,
MD,
Forensic pathologist and Radiologist,
PhD student in Oncological Sciences at the Department of Radiological Sciences,
Catholic University of Rome,
Italy.
E-mail:
[email protected]
References
1. Lee MJ,
Kim S,
Lee SA et al.
Overcoming artifacts from metallic orthopedic implants at high-field-strength MR imaging and multi-detector CT.
Radiographics 2007;27:791-803.
2. Watzke O,
Kalender WA.
A pragmatic approach to metal artifact reduction in CT: merging of metal artifact reduced images.
Eur Radiol 2004;14:849-856.
3. Barrett JF,
Keat N.
Artifacts in CT: recognition and avoidance.
Radiographics 2004;24:1679-1691.
4. Haramati N,
Staron RB,
Mazel-Sperling K et al.
CT scans through metal scanning technique versus hardware composition.
Comput Med Imaging Graph 1994;18:429-434.
5. White...