Correction of Metal-Induced MRI Artifacts in Total Knee Replacements with MAVRIC and SEMAC

77 Pages·2012·4.4 MB·English

by  Tina Chen

Imaging around metallic
implants using MRI
Garry E. Gold, MD
Professor of Radiology
Stanford University
Thursday, September 6, 12
Metallic implants increasingly
used in medicine
(cid:2)
Stents
(cid:2)
Fracture fixation
(cid:2)
Spinal fusion
(cid:2)
Joint reconstruction after tumor
resection
Spinal Fusion Implant
Thursday, September 6, 12
Metallic implants increasingly
used in medicine
(cid:2)
Stents
(cid:2)
Fracture fixation
(cid:2)
Spinal fusion
(cid:2)
Joint reconstruction after tumor
resection
Spinal Fusion Implant
Thursday, September 6, 12
Total Knee Replacements
(cid:2)
Total knee replacements (TKRs) increasing in
prevalence
(cid:2)
In 2006: >540,000 primary TKRs and 39,000
revision TKRs
(cid:2)
2005 to 2030: Primary and revision total knee
arthroplasty expected to grow 673%
• (cid:2)(cid:3)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:9)(cid:10)(cid:7)(cid:3)(cid:11)(cid:12)
(cid:2) (cid:13)(cid:11)(cid:14)(cid:15)(cid:8)(cid:10)(cid:7)(cid:3)(cid:11)
(cid:2) (cid:16)(cid:15)(cid:17)(cid:7)(cid:5)(cid:17)(cid:3)(cid:12)(cid:10)(cid:18)(cid:15)(cid:10)(cid:7)(cid:8)(cid:19)(cid:3)(cid:12)(cid:10)(cid:15)(cid:3)(cid:6)(cid:20)(cid:12)(cid:7)(cid:12)
(cid:2) (cid:21)(cid:12)(cid:15)(cid:5)(cid:10)(cid:7)(cid:8)(cid:22)(cid:4)(cid:15)(cid:8)(cid:18)(cid:9)(cid:11)(cid:7)(cid:8)(cid:9)(cid:6)(cid:19)(cid:6)(cid:3)(cid:3)(cid:12)(cid:15)(cid:11)(cid:7)(cid:11)(cid:23)
(cid:2) (cid:24)(cid:15)(cid:9)(cid:17)(cid:19)(cid:3)(cid:14)(cid:19)(cid:9)(cid:17)(cid:10)(cid:7)(cid:8)(cid:25)(cid:6)(cid:9)(cid:17)(cid:19)(cid:26)(cid:15)(cid:9)(cid:17)(cid:7)(cid:11)(cid:23)(cid:19)(cid:12)(cid:25)(cid:17)(cid:14)(cid:9)(cid:8)(cid:15)
(cid:2) (cid:16)(cid:15)(cid:17)(cid:7)(cid:5)(cid:17)(cid:3)(cid:12)(cid:10)(cid:18)(cid:15)(cid:10)(cid:7)(cid:8)(cid:19)(cid:14)(cid:17)(cid:9)(cid:8)(cid:10)(cid:25)(cid:17)(cid:15)
X-ray of osteolysis
Thursday, September 6, 12
Motivation
(cid:2)
MRI is the method of choice for examination of joints
(cid:2)
Evaluation of metallic implants is now limited to x-ray or
CT scan with artifacts
(cid:2)
MRI is extremely limited around metal implants due to
artifacts (signal loss and distortion)
(cid:2)
Goal: Enable the routine use of MRI around metal
Osteosarcoma Pre-op
Thursday, September 6, 12
Motivation
(cid:2)
MRI is the method of choice for examination of joints
(cid:2)
Evaluation of metallic implants is now limited to x-ray or
CT scan with artifacts
(cid:2)
MRI is extremely limited around metal implants due to
artifacts (signal loss and distortion)
(cid:2)
Goal: Enable the routine use of MRI around metal
Post-o p xO-srateyosarcoma PPores-t-oopp CT w/ artifact
Thursday, September 6, 12
Motivation
(cid:2)
MRI is the method of choice for examination of joints
(cid:2)
Evaluation of metallic implants is now limited to x-ray or
CT scan with artifacts
(cid:2)
MRI is extremely limited around metal implants due to
artifacts (signal loss and distortion)
(cid:2)
Goal: Enable the routine use of MRI around metal
Conventional MRI w/ artifact
Osteosarcoma Pre-op
Thursday, September 6, 12
Metal in MRI
Displacement artifacts near metal. During excitation, a selection
gradient causes a frequency variation (black arrows) but
frequency shifts cause highlighted spins to be excited in the wrong
slice. During imaging readout, the gradient induces a frequency
variation, and the off-resonant spin appears to be at the wrong
location. The displacements lead to bulk distortion, signal loss
and pile-up effects.
Brian Hargreaves, Ph.D.
Thursday, September 6, 12
MR imaging of patients with
hardware:
Factors influencing visualization
Thursday, September 6, 12
MR imaging of patients with
hardware:
Factors influencing visualization
• Hardware
• Alloy type
• Susceptibility
Thursday, September 6, 12