12/12/2015 Objectives : Lower Extremity Imaging Lower Extremity Imaging – What to � Different Imaging Modalities Order and How to Interpret the Report � Imaging orders that make you look “awesome” C. Benjamin Ma, MD � Interpretation of reports Professor in Residence Shoulder and Sports Medicine University of California, San Francisco Department of Orthopaedic Surgery Why image? Imaging � New injuries � Aid diagnosis � Chronic problems � Determine significance � Rule out tumor � Allow treatment plan 1
12/12/2015 Different Modalities Pearls � Write down what you are concerned � Radiographs about � Ultrasound � Xrays of ankle with concern of � CT scan fibular fracture � Bone scan � MRI of knee with recurrent instability � MRI � Radiologists can help getting the right studies for you � They can also suggest better studies Plain radiographs Plain radiographs � Good first line evaluation � Image obtained by projecting of � The amount of ‘ whiteness ’ is a � Orthogonal views (projection!) x-ray beams onto a detector � AP/lateral of the joint function of the radiodensity and thickness of the object � Dense object – whiter image 2
12/12/2015 Lower extremity imaging What to order? Make you look good! � Knee � Lower extremity are weight � AP and Lateral knee bearing joints. � Weight bearing AP � Joint alignment can be very � Patellofemoral views different with weight bearing � Can get weight bearing x-rays to look at joint space and alignment What to order? What to order? � Ankle � Hip � AP/lateral ankle � AP/ frog leg lateral � Mortise view of ankle � AP pelvis 3
12/12/2015 What to order? What to look for? � Fractures � Foot � Displaced � AP/lateral/oblique foot � Comminuted � Weight bearing lateral? � Impacted � Arthritis � Mild, moderate, severe � Abnormal morphology � Spurs, OCD, deformities Interpretation Ultrasound � Displaced fractures – always need � Uses high-frequency sound waves to produce images attention � Similar to sonar wave on getting images of � Non displaced fracture – can the ocean � Can be helpful to evaluate ganglion cyst immobilize � Knee ganglions � Stress fracture/ cannot rule out…. � Foot ganglions � Diagnose tendon tears � Need secondary evaluation � Foot peroneal tendon injuries � Further imaging � Achilles tendon ruptures � Closer followup 4
12/12/2015 Ultrasound Ultrasound � Advantages � Use for targeted therapy � Non-invasive • Ultrasound guided injections � Dynamic - Hip injections • Tendon instability - Calcific tendinitis � Disadvantage � User-dependent � Cannot image deep tissue � Cannot image tissue within bone CT scan CT scan � Advantages � Tomographic evaluation of the � Tomographic evaluation region of interest � No magnification � Good for 3D bony anatomy � Give detail in trabecular and cortical structures (better than MRI) � Degenerative joint anatomy • Measure bone loss • Evaluate fracture pattern � Complex reconstruction • Evaluate healing � Post-traumatic injuries � Ankle malunion 5
12/12/2015 CT scan Nuclear imaging � Uses radioisotope-labelled biological � Disadvantages active drugs � Subject to metal artifact � Radioactive tracers administered to the patient to serve as markers of � Weight limit for obese patients biologic activity � Higher radiation � Images produced by scintigraphy � Technetium bone scan � Contraindicated for pregnant � FDG in PET scans patients • Measure glycolytic rates • Higher in tumor cells Bone scan Nuclear medicine � Advantages � Rule out tumor – multiple lesions, � Imaging of metabolic activity increase update • Healed fracture or nonunion • Arthritis � Infection – tagged WBC scan � Diagnosis of infection � Evaluate symptomatic joints � Disadvantages � Lack detail and spatial resolution � Such as arthritis � Limited early sensitivity � Nonunion • Fractures usually takes up to several days to show up � Stress fractures � Low sensitivity for lytic problems • Multiple myeloma 6
12/12/2015 MRI MRI with contrast -Gadolinum � Intra-articular contrast � Current gold standard for soft tissue injuries � Distends the joint � Enable evaluation of � Ligament tears ligament and labrum � Labral tears � Hip labral tears � Cartilage injuries � Meniscus repairs � Meniscus tears MRI MRI- Gadolinum � Intravenous contrast � Helpful to evaluate � Evaluate vascularity ligament integrity � Quality of cartilage � Tumor � fraying � Post-surgical changes, such as � arthritis scar tissue � Labrum and � Concern with kidney meniscus injuries insufficiency and complications � Usually ordered by specialists 7
12/12/2015 MRI MRI � Helpful to evaluate � Helpful to evaluate ligament integrity ligament integrity � Quality of cartilage � Quality of cartilage � fraying � fraying � arthritis � arthritis � Labrum and � Labrum and meniscus injuries meniscus injuries Radiology Reports – love adjectives! How do you interpret the report ? � Fraying vs Partial tear vs Full � What are the big words? thickness tear (Mucoid Degeneration) � Fractures � Cartilage inhomogeneity vs fissure vs � Tears / disruption – full flap vs unstable flap vs full thickness thickness cartilage loss � Displaced…. � Tendon degeneration vs tendinosus � Lesion possible neoplasm vs tear � Advanced….arthritis Clinical Correlation Recommended 8
12/12/2015 What are they saying? Knee MRI What are they saying? Knee xray MENISCUS: There is a complex tear of the body and posterior horn � of the medial meniscus with large bucket-handle fragment � INDICATION: Age: 17 years. Gender: Male. History: displaced into the intercondylar notch paralleling the posterior pain vs injury r/o fracture cruciate ligament. � Bones and joints: Osseous fragment over the superior The native torn ACL is seen to be flipped anteriorly and back on � pole of patella with marked thickening and irregularity itself within the anterior aspect of the intercondylar notch. of the quadriceps tendon. IMPRESSION: � � Soft tissues: Large joint effusion with patellar soft 1. Flipped appearance of the native torn ACL within the anterior � tissue swelling. aspect of the intercondylar notch is consistent with stump entrapment/cyclops lesion. � IMPRESSION: 2. Large bucket-handle tear of the posterior horn and body of the � Osseous fragment over the superior pole of the patella � medial meniscus. with marked thickening and irregularity of the quadricep tendon with large joint effusion. Findings most compatible with superior pole patellar sleeve fracture. What are they saying? Foot What are they saying? MRI Hip LABRUM: Degenerative tearing of the anterior and superior � � CLINICAL HISTORY: r/o fx at left 5th MTP. labrum. Degenerative ossification is also seen in the anterior labrum (image 17, series 4). jammed foot 3 days ago. LIGAMENTS: The ligamentum teres and transverse acetabular � IMPRESSION: � ligament are intact. Linear low signal intensity medial to the � 1. Mildly to moderately displaced extra-articular ligamentum teres may represent a thick acetabular plica. oblique fracture of the fifth metacarpal shaft. No TENDONS: The visualized rectus femoris, proximal hamstring, � 65 yo with mild hip arthritis and tendinitis and iliopsoas tendons are intact. Edema around the gluteus evidence of dislocation. tendon insertion, greater around the minimus than the medius, is Age appropriate changes � 2. Severe degenerative changes of the first MTP compatible with mild peritendinitis. joint compatible with hallux rigidus. IMPRESSION: � 1. Degenerative tearing of the anterior and superior labrum. � 2. Focal chondral loss Along the superolateral and anterior � femoral acetabular cartilage. Focal chondral loss along the posterior medial aspect acetabular cartilage. 3. Mild peritendinitis of the gluteus tendon insertion, greater � around the minimus than the medius. 9
12/12/2015 Asymptomatic Lesions Lower Extremities Imaging � Write down what your question is � High prevalence of meniscus tears � Radiology can help answer them in older individuals � Plain radiography – first start � Especially with osteoarthritis (91%) � Acute injuries – can order further � May not be symptomatic imaging or quick referral � “complex” tear is an appearance, � Chronic injuries – can order further may not be symptomatic imaging and interpret results � Post op injuries - referral Lower Extremities Imaging What to order – lower extremities � Chicken Feet � Orthogonal views of xrays � Pig’s Knuckle � Advanced imaging can be helpful � Osso Bucco but careful with interpretation � Not all “tears” are bad 10
12/12/2015 Thank you � C. Benjamin Ma, M.D. Professor in Residence UCSF Department of Orthopaedic Surgery Sports Medicine and Shoulder (415) 353-7566 maben@orthosurg.ucsf.edu 11
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