MRI OF PROTHETIC IMPLANTS IN MSK Nathalie CHEMLA MD, Eric PESSIS MD, Clinic Paris V Cochin Hospital Paris CCN Saint Denis France

MRI OF PROTHETIC IMPLANTS IN MSK The use of MRI in the presence of metallic hardware has traditionally been limited by susceptibility artifacts generated by the presence of the metallic components. With arthroplasty being increasingly used to relieve joint pain, imaging of patients with large metal implants represent a significant part of the radiologist’s daily practice

PULSE PARAMETERS MODIFICATIONS ON SE Maximize the bandwidth Imaging at 1.5 T, instead of 3 T Thin sections Large matrix (encoding phase perpendicular to métal axis) High number of excitations A number of modifications of pulse parameters can be easily applied to conventional fast spin-echo (FSE) techniques to improve visualization of the soft tissues surrounding an arthroplasty .SUCH AS

STIR AND METAL ARTIFACTS Use STIR imaging to avoid failure of fat suppression (instead of frequency-selective fat suppression

MAVRIC ( multiacquisition variable-resonance image combination ) However, these factors can be not sufficient. More recently, new technique such as (MAVRIC) : a method to correct displacement artifacts

STIR MAVRIC Il looks like the head had cross the cotyl

MAVRIC 3D Fast Spin Echo PD technic With or without IR (fat sat effect) multiple overlapping volumes . Helps eliminate through-plane distortions and reduce in-plane artifacts. The combined images have minimal artifact and include signal from a wide range of frequency offsets near metal.

MAVRIC Maximize bandwith FOV: minimum 18 cm to avoir aliasing wrap-around Minimum 5 mm slices 110° angle to reduce SAR (specific absorbtion rate) High matrix To opyimize

TENDINITIS AND STRESS FRACTURE screw TENDINITIS AND STRESS FRACTURE

CUBE VERSUS MAVRIC Cancellous bone oedema because of chondropathy

Hip arthroplasty: osseous integration Using conventional SE T1 and STIR MR imaging technique, the regions of bone around the metal implants are obscured by artifacts (white arrows). MAVRIC image show improved clarity and help to visualize bone-stem interface (yellow arrows) T1 STIR MAVRIC

Hip arthroplasty :osseous integration Complete osseous integration of a cementless hip arthroplasty implant : direct contact between the implant and the surrounding trabecular bone without separation. Using conventional FSE T2 with fat suppression MR imaging technique, the regions of bone around the metal femoral implant is obscured by artifacts (white arrow) MAVRIC image show improved clarity and help to visualize direct contact of the implant (yellow arrow) and the surrounding cancellous bone FSE T2 with fat suppression MAVRIC

TOTAL KNEE ARTHROPLASTY: OSTEOLYSIS Periprosthetic osteolysis over the anterior aspect of tibial peg ( red arrow) well visualized on plain film and Not visible on FSE T2 with water excitation (IDEAL) MR image FSE T2 IDEAL

Total knee arthroplasty: osteolysis Periprosthetic osteolysis over the anterior aspect of tibial peg (red arrow) is well visualized on T2 MAVRIC image and Not visible on correspondant FSE T2 with water excitation (IDEAL) image Sagittal T2 MAVRIC FSE T2 IDEAL

Lumbar disk arthroplasty at the L4-L5 level Conventional plain film and MR images of the lumbar spine (SE T1 and FSE T2 sequences) show severe artifacts from orthopedic hardware that obscure the anatomy and limit evaluation of the spinal canal with MRI (yellow arrows). Corresponding MAVRIC image show significant reduction of artifact in the spinal canal (white arrow). SE T1 FSE T2 T2 MAVRIC

Screw fixation of a sacroiliac joint disruption Conventional MR images of the lumbar spine (SE T1 and FSE T2 sequences) show severe artifacts from a screw that obscure the anatomy and limit evaluation of the spinal canal with MRI (yellow arrows). Corresponding MAVRIC image show significant reduction of artifact in the spinal canal (white arrow). FSE T2 SE T1 FSE T2

Screw fixation of a sacroiliac joint disruption Conventional sagittal MR image of the lumbar spine (FSE T2 sequence) shows severe artifacts from a screw that limit evaluation of the spinal canal (yellow arrow). Corresponding MAVRIC images shows significant reduction of artifact in the spinal canal (white arrow). FSE T2 T2 MAVRIC T2 MAVRIC

SE and corresponding MAVRIC images show significant reduction of artifact in the spinal canal especially on axial plan. T2SE MAVRIC Is there disk herniation ? Mavric: no disk hernation

CERVICAL SYRINX BETTER ANALYSIS WITH MAVRIC

Conclusion Multiacquisition Variable-Resonance Image Combination (MAVRIC) Method Allows to reduce substantially artifacts from metal implants at MRI Improve visualization of metal-to-bone interface Improve the visualization of soft tissue near and far the metallic implant Evaluation of metal implants and adjacent bone or tissue is enhanced with MAVRIC images

THANKS TO DR ERIC PESSIS THANKS TO ERIC LÉVÊQUE

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