An in silico testbed for fast and accurate MR labeling of orthopedic implants
Figures
![](https://iiif.elifesciences.org/lax:90440%2Felife-90440-fig1-v1.tif/full/617,/0/default.jpg)
Visible Human Project (VHP)-Female Model with Embedded Passive Implants.
Left (a) – surface CAD meshes for the Visible Human Project (VHP)-Female model (with some muscles removed for purposes of visualization); and right – examples of passive femoral implants embedded into the model. (b–d) At top right – physical femoral implants; (e–g) at center and bottom – anatomically justified CAD realization within the virtual human VHP-Female. An Austin Moore implant is shown in b; a short proximal femoral nail with the proximal hip (a large femoral neck screw) is given in c; a long proximal femoral nail with the proximal hip is presented in d.
![](https://iiif.elifesciences.org/lax:90440%2Felife-90440-fig2-v1.tif/full/617,/0/default.jpg)
Left – Visible Human Project (VHP)-Female computational phantom positioned within a 1.5 T MRI birdcage coil at the abdominal landmark.
Right – power loss density in W/m3 in the coil for the (b) Austin Moore and (c) femoral nail implants.
![](https://iiif.elifesciences.org/lax:90440%2Felife-90440-fig3-v1.tif/full/617,/0/default.jpg)
Ansys Workbench modeling workflow consisting of the HFSS (electromagnetic) module labeled as A and B, and the transient thermal module labeled D.
Thermal material properties are contained in module C.
![](https://iiif.elifesciences.org/lax:90440%2Felife-90440-fig4-v1.tif/full/617,/0/default.jpg)
Top – long femoral nail subject to three repetitions of 15 min exposure followed by 5 min of rest for 1 hr in total.
Center – temperature contour plot in a cut plane roughly bisecting the embedded femoral implant at the end of the last heating cycle. Bottom – temperature rise profile at the temperature probe. Only the bone is shown but the computations are performed for the entire model.
![](https://iiif.elifesciences.org/lax:90440%2Felife-90440-fig5-v1.tif/full/617,/0/default.jpg)
Liver experiment setup: E-field distribution in the plane of the resonant loop and specific absorption rate (SAR) distribution within liver in a plane passing through the tip of the lead.
Bottom left – lesion in a section of ex vivo bovine liver created with heating at the tip of a 16 gauge (1.3 mm) bare copper wire needle in about 1.5 min (Hue et al., 2018).