U Penn Diagnostic Imaging: On the Cape Chatham, MA July 11-15, 2016 Viviane Khoury, MD Assistant Professor Department of Radiology University of Pennsylvania
Hip imaging has changed in recent years: new insights into anatomy and biomechanics developments in hip-preserving surgery technological advances in imaging (3T MRI, improvements in US technology) Imaging modalities: Radiographs- remain basis for any hip pathology Magnetic resonance imaging (MRI)- paramount for intra-articular pathology (e.g. cartilage and labrum in FAI) Ultrasound Computed tomography (CT)
Intra-articular lesions Labrum and cartilage (/femoroacetabular impingement) Extra-articular lesions Rotator cuff tendons Snapping hip syndrome Athletic pubalgia Indications for each imaging modality
61F- severe OA Labral tears and cartilage lesions in the young occur 2 0 : 20M-right hip pain Hip dysplasia FAI Other (Legg- Calve-Perthes, old trauma, )
A common cause of early OA Divided into CAM-type (femoral abnormalities) and pincer-type (acetabular abnormalities) Initial imaging: X-rays AP, frog-leg, Dunn views- Good technique imperative 28M 24M Normal
Safran MR. J Am Acad Orthop Surg 2010;18:338-345
Labrum has an oblique orientation in the standard imaging planes (ax, cor, sag) www.biology.clc.uc.edu
Coronal pelvis MR-arthrogram Smaller FOV Smaller FOV + 3T
Sagittal plane
MR arthrography vs MRI: Meta-analysis: Accuracy of MR-A is superior Sensitivity: MRI 66%, MR-A 87% Specificity: MRI 79%, MR-A 64% Smith TO, et al. Eur Radiol 2011; 21(4):863-74 If optimize the MR-A study: Combination of 3 sequences detected 96% tears in 144 patients who underwent arthroscopy Sagittal T1 fat-saturation Axial-oblique T1 fat-saturation Coronal T2 fat-saturation Ziegert AJ, et al. AJR 2009; 192:1397-1400
Fluoro-guided intra-articular injection of gadolinium solution(10-15 ml) Disadvantages: Invasive, uncomfortable (however: moderate pain average 2 d) Giaconi JC, et al. AJR 2011;196(4):868-874 An extra step: increased cost and time (however: increased accuracy and indication for surgical intervention)
Variations in shape: Triangular (~70%), round, flat Absent (controversial) 2 basic types of labral tears: Degenerative Traumatic Intrasubstance Detachment Most are anterosuperior > posterosuperior Czerny C et al. Radiology. 1996 Jul;200(1):225-30
axial-oblique fat-sat T1 Sagittal
20M- waterpolo player hip/groin pain: anterosuperior tear 32F- refractory hip pain since MMA injury 9 months: posterior tear
Sublabral recess in 18% (anterior, anterosuperior) Posteroinferior sulcus in 23% Absence of anterior portion of labrum in 10-14% Bifid posterior labrum (rare) 19M Normal posterior sulcus Axial-oblique
46 o Normal: <55 o used most often as threshold (vs. 50 o ) Only one part of decision for surgery (also acetabulum and clinical factors) Controversy: 62 o Cam-deformities in 1:4 asx young males Alpha angles >50 o in 53%, >55 o in 33.5% in asx Hack K, et al. JBJS 2010:92(14):2436-2444 F/u of 96 asx pts over 19 years: 82% free of OA Hartofiladikis G, et al. JBJS r 2011;93(5):580-586
20M- normal With leg traction: 53M From: Sutter R, Zanetti M, Pfirrmann C. Radiology. 2012 Sep;264(3):651-67
58 M Overall: Sensitivity: 41%-79% Specificity: 77%-100% Byrd JW, Jones KS. Am J Sports Med. 2004 Oct- Nov;32(7):1668-74 Coronal Hypointense areas in the acetabular cartilage: 90% specificity on coronal PD, 90-95% on T1
28F mild dysplasia A common finding in FAI undergoing surgery Fluid (gadolinium) under the cartilage Not common but very specific
Llopis MD, Fernandez E, Cerezal L. Semin Musculoskelet Radiol 2012 Feb;16(1):42-56
Grading cartilage lesions before macroscopic changes ( pre-clinical cartilage damage) Not yet implemented in routine clinical imaging Techniques include dgemric (delayed gadolinium-enhanced MRI of cartilage) T2 mapping (changes in H 2 0 content and arrangement of collagen structure) T2* mapping (allows fro 3D mapping) T1rho-weigthed MRI (loss of proteoglycans)
Indirectly measures GAGs After iv or ia gadolinium Loss of GAG = decrease negative charge density shortening of T1 Sag MR-arthrogram From: Sutter R, Zanetti M, Pfirrmann C. Radiology. 2012 Sep;264(3):651-67
Refers to a painful audible snap during motion May occur in asymptomatic individuals (~50%) Intraarticular causes: Extraarticular causes: Role for US labral tears intraarticular bodies osteochondral fractures snapping of iliopsoas tendon friction of ITB or gluteus maximus snapping of iliofemoral ligament transient subluxation of femoral head
T
Left hip muscle tendon
Sagittal T2 FS Ultrasound
C
cyst Iliopsoas tendon
Zoga AC, Mullens FE, Meyers WC. Radiol Clin North Am. 2010 Nov;48(6):1179-97
**Need dedicated MRI protocol for athletic pubalgia 38M- Rt groin pain Zoga AC, Mullens FE, Meyers WC. Radiol Clin North Am. 2010 Nov;48(6):1179-97
Cor FS T2 MRI
Advances in knowledge pathophysiology and in imaging technology have changed the way the hip joint is imaged Xrays and MRI can be used to detect acetabular overcoverage and morphological deformities of the femur New technology optimizes detection of labral and cartilage lesions of the hip FAI concept widely accepted- relevance remains controversial in borderline cases
Cartilage mapping techniques promising- but not yet used in routine clinical practice Beware of common variants/pitfalls Role for US in snapping hip Dedicated protocols for athletic pubalgia allow detection of RA/adductor aponeurosis injuries