Transcript spect-ct
The following presentation was given at the Radiological Society of North America (RSNA) in 2012 [email protected] Multimodality Assessment of Metal-onMetal Hip Arthroplasties Never Miss a Diagnosis Again on Plain Radiographs, MARS MRI and SPECT-CT Sabah, S. A., Satchithananda, K., Henckel, J., Mitchell, A. W., Barwick, T., Khan, S., Eccles, A., Hirschmann, M., Hart, A. J. 1 Introduction | Plain Radiographs | MARS MRI | SPECT-CT Disclosures • Dr. K. Satchithananda – Johnson & Johnson Committee Member Introduction | Plain Radiographs | MARS MRI | SPECT-CT Overview • Introduction to metal-onmetal hip arthroplasty • Assessment of unexplained hip pain • Imaging modalities – Plain radiographs – MARS MRI – SPECT-CT Introduction | Plain Radiographs | MARS MRI | SPECT-CT Metal-on-metal hip arthroplasty • First popular design introduced by McKee in 1951 • Failure through aseptic loosening due to high torque • Superseded by Charnley lowfriction arthroplasty http://global.smith-nephew.com/us/BHR_IF_GEORGE_KENETH_MCKE_15656.htm Introduction | Plain Radiographs | MARS MRI | SPECT-CT MOM Resurgence • Sold as hip replacements to last a lifetime • Promise of: – Low component wear rate – Femoral bone conservation – Low rate of dislocation • Approaching 1 million MOM hips implanted in US over past decade National Joint Registry for England and Wales 9th Annual Report Introduction | Plain Radiographs | MARS MRI | SPECT-CT MOM Controversy • Higher failure rates compared to traditional hip types National Joint Registry for England and Wales - 9th Annual Report Introduction | Plain Radiographs | MARS MRI | SPECT-CT MOM Controversy • Withdrawal of DePuy ASR prosthesis Introduction | Plain Radiographs | MARS MRI | SPECT-CT MOM Controversy • Concern over soft tissue lesions and raised metal ions Introduction | Plain Radiographs | MARS MRI | SPECT-CT Reasons for revision • Pain • Aseptic loosening • Infection Introduction | Plain Radiographs | MARS MRI | SPECT-CT Unexplained hip pain Henderson. JBJS(Br) 2012. 94(B):145-51 MHRA Device Bulletin. MDA/2012/036 Introduction | Plain Radiographs | MARS MRI | SPECT-CT Plain Radiographs Hip resurfacing Total Hip Prosthesis Introduction | Plain Radiographs | MARS MRI | SPECT-CT Component Orientation • Acetabular inclination Murray, DW. JBJS(Br). 1993; 75-B:228-32. Hart, AJ. Hip Int. 2009; 19:323-9 Introduction | Plain Radiographs | MARS MRI | SPECT-CT Malposition • Raised inclination (‘Vertical cup’) Malposition • Anteverted femoral stem (retroverted femoral component) Malposition • Retroverted acetabular component Introduction | Plain Radiographs | MARS MRI | SPECT-CT Impingement Introduction | Plain Radiographs | MARS MRI | SPECT-CT Periprosthetic fracture • Femoral neck fracture Aseptic loosening • Femoral component Introduction | Plain Radiographs | MARS MRI | SPECT-CT Aseptic loosening • Gross acetabular loosening Introduction | Plain Radiographs | MARS MRI | SPECT-CT Dislocation Introduction | Plain Radiographs | MARS MRI | SPECT-CT Stem Fracture Introduction | Plain Radiographs | MARS MRI | SPECT-CT Trochanteric resorption Introduction | Plain Radiographs | MARS MRI | SPECT-CT Metal-artifact reduction sequence MRI • Artifact reduction techniques Introduction | Plain Radiographs | MARS MRI | SPECT-CT Metal-artifact reduction sequence MRI • Reporting protocol Introduction | Plain Radiographs | MARS MRI | SPECT-CT Metal-artifact reduction sequence MRI • Imperial Classification Lesion category Wall Contents Shape Thin walled Fluid like: T1 hypo / T2 hyper Flat with walls mainly in apposition Class 2A Thick walled or irregular Fluid like: T1 hypo / T2 hyper Not flat and >50% of the walls are not in apposition Class 2B Thick walled or irregular Atypical fluid: T1 hyper / T2 variable Any size Class 3 Solid Mixed signal Any size Class 1 Hart, AJ. JBJS(Am). 2012; 94(4):317-325 Introduction | Plain Radiographs | MARS MRI | SPECT-CT Pseudotumors • Imperial Type 1 Pseudotumor Cor STIR Introduction | Plain Radiographs | MARS MRI | SPECT-CT Pseudotumors • Imperial Type 2A Pseudotumor Ax T2W Introduction | Plain Radiographs | MARS MRI | SPECT-CT Pseudotumors • Imperial Type 2B Pseudotumor Ax T2W Ax T1W Ax T2W Introduction | Plain Radiographs | MARS MRI | SPECT-CT Pseudotumors • Imperial Type 3 Pseudotumor Ax T1W Cor T1W Introduction | Plain Radiographs | MARS MRI | SPECT-CT Pseudotumors • Infected Pseudotumor Ax T2W Introduction | Plain Radiographs | MARS MRI | SPECT-CT Metal-artifact reduction sequence MRI • Anderson Classification Anderson, H. Skeletal Radiol. 2011. 40:303-307 Introduction | Plain Radiographs | MARS MRI | SPECT-CT Periprosthetic hip musculature • Grading – Assessed on T1W images – Compared to contralateral side Grade Comment 0 Normal 1 ≤30% decrease in muscle size 2 30-70% fatty change with decrease in muscle mass 3 >70% fatty change with an 80% decrease in size Bal, BS. Instr Course Lec. 2008. 56:223-230. Introduction | Plain Radiographs | MARS MRI | SPECT-CT Periprosthetic hip musculature • Abductor anatomy Minimus Medius Maximus Introduction | Plain Radiographs | MARS MRI | SPECT-CT Tendinopathy • Pfirrmann system to assess: – Tendon signal – Tendon diameter – Tendon ossification Introduction | Plain Radiographs | MARS MRI | SPECT-CT Tendinopathy • Abductor tendon avulsion due to soft tissue lesion Ax T1W TSE P2 Cor STIR Introduction | Plain Radiographs | MARS MRI | SPECT-CT SPECT-CT • Hybrid imaging modality + = Introduction | Plain Radiographs | MARS MRI | SPECT-CT SPECT-CT • Uses of SPECT-CT – Occult infection – Aseptic loosening – Mechanical symptoms – Localisation of pathology to the hip Introduction | Plain Radiographs | MARS MRI | SPECT-CT SPECT-CT • Infection – Best seen on early blood pool images Introduction | Plain Radiographs | MARS MRI | SPECT-CT SPECT-CT • Femoral head loosening – ‘Hotspot’ under component Introduction | Plain Radiographs | MARS MRI | SPECT-CT SPECT-CT • Stem loosening Introduction | Plain Radiographs | MARS MRI | SPECT-CT SPECT-CT • Mechanical Symptoms – Eccentric femoral stem – ‘Hotspot’ at tip Introduction | Plain Radiographs | MARS MRI | SPECT-CT SPECT-CT • Incidental pathologies L5/S1 disc pathology accounted for unexplained ‘hip’ pain in this patient Summary • Multimodality assessment permits diagnosis of unexplained hip pain • We recommend post-op surveillance with plain radiographs and MARS MRI • SPECT-CT for occult infection, aseptic loosening, mechanical symptoms and to localize pathology to hip