What to Order and How to Interpret the Report C. Benjamin Ma, MD - PDF document

12/1/2017 What to Order and How to Interpret the Report C. Benjamin Ma, MD Professor in Residence Shoulder and Sports Medicine University of California, San Francisco Department of Orthopaedic Surgery Imaging  Different types of imaging  Imaging orders that make you look “awesome”  Interpretation of reports 1

12/1/2017 Why image?  New injuries  Chronic problems  Rule out tumor Imaging  Aid diagnosis  Determine significance  Allow treatment plan 2

12/1/2017 Different Modalities  Radiographs  Ultrasound  CT scan  Bone scan  MRI Pearls  Write down what you are concerned about  Xrays of ankle with concern of fibular fracture  MRI of shoulder with recurrent instability  Radiologists can help getting the right studies for you  They can also suggest better studies 3

12/1/2017 Plain radiographs  Image obtained by projecting of x-ray beams onto a detector  The amount of ‘ whiteness ’ is a function of the radiodensity and thickness of the object  Dense object – whiter image Plain radiographs  Good first line evaluation  Orthogonal views (projection!)  AP/lateral of the joint 4

12/1/2017 Lower extremity imaging  Lower extremity are weight bearing joints.  Joint alignment can be very different with weight bearing  Can get weight bearing x-rays to look at joint space and alignment What to order? Make you look good!  Knee  AP and Lateral knee  Weight bearing AP  Patellofemoral views 5

12/1/2017 What to order?  Hip  AP/ frog leg lateral  AP pelvis What to order?  Ankle  AP/lateral ankle  Mortise view of ankle 6

12/1/2017 What to order?  Foot  AP/lateral/oblique foot  Weight bearing lateral? Upper extremity imaging - shoulder  AP of GH joint  Axillary lateral  Supraspinatus outlet view  AP of AC joint 7

12/1/2017 Upper extremity imaging – non weight bearing joints  Elbow  AP/lateral forearm What to order?  Wrist  AP/lateral/oblique wrist 8

12/1/2017 What to order?  AP Hand  Lateral Hand Interpretation  Displaced fractures – always need attention  Non displaced fracture – can immobilize  Stress fracture/ cannot rule out….  Need secondary evaluation  Further imaging  Closer followup 9

12/1/2017 What to look for?  Fractures  Displaced  Comminuted  Impacted  Arthritis  Mild, moderate, severe  Abnormal morphology  Spurs, OCD, deformities Interpretation  Elbow “Sail sign”  Occult fractures  Pediatric – supracondylar fractures 10

12/1/2017 Specific Radiographic Studies  Wrist  Scaphoid view  Hamate view Ultrasound  Uses high-frequency sound waves to produce images  Similar to sonar wave on getting images of the ocean  Can be helpful to evaluate ganglion cyst  Knee ganglions  Foot ganglions  Diagnose tendon tears  Rotator cuff tears  Achilles tendon ruptures 11

12/1/2017 Ultrasound  Advantages  Non-invasive  Dynamic • Tendon instability  Disadvantage  User-dependent  Cannot image deep tissue  Cannot image tissue within bone Ultrasound  Use for targeted therapy • Ultrasound guided injections - Hip injections - Calcific tendinitis - Shoulder injections 12

12/1/2017 CT scan  Tomographic evaluation of the region of interest  Good for 3D bony anatomy  Degenerative joint anatomy  Complex reconstruction  Post-traumatic injuries  Ankle malunion CT scan  Advantages  Tomographic evaluation  No magnification  Give detail in trabecular and cortical structures (better than MRI) • Measure bone loss • Evaluate fracture pattern • Evaluate healing 13

12/1/2017 3D CT scan CT Scan  Hamate Fracture 14

12/1/2017 CT scan  Disadvantages  Subject to metal artifact  Weight limit for obese patients  Higher radiation  Contraindicated for pregnant patients Nuclear imaging  Uses radioisotope-labelled biological active drugs  Radioactive tracers administered to the patient to serve as markers of biologic activity  Images produced by scintigraphy  Technetium bone scan  FDG in PET scans • Measure glycolytic rates • Higher in tumor cells 15

12/1/2017 Bone scan  Rule out tumor – multiple lesions, increase update  Infection – tagged WBC scan  Evaluate symptomatic joints  Such as arthritis  Nonunion  Stress fractures Nuclear medicine  Advantages  Imaging of metabolic activity • Healed fracture or nonunion • Arthritis  Diagnosis of infection  Disadvantages  Lack detail and spatial resolution  Limited early sensitivity • Fractures usually takes up to several days to show up  Low sensitivity for lytic problems • Multiple myeloma 16

12/1/2017 MRI  Current gold standard for soft tissue injuries  Ligament tears  Labral tears  Cartilage injuries  Meniscus tears MRI  Helpful to evaluate ligament integrity  Quality of cartilage  fraying  arthritis  Labrum and meniscus injuries 17

12/1/2017 MRI  Helpful to evaluate ligament integrity  Quality of cartilage  fraying  arthritis  Labrum and meniscus injuries MRI  Helpful to evaluate ligament integrity  Quality of cartilage  fraying  arthritis  Labrum and meniscus injuries 18

12/1/2017 MRI  Helpful to evaluate cuff integrity  Quality of muscle  Fatty infiltration  Retracted tear  Labral pathology OCD of the elbow 19

12/1/2017 TFCC tear  Triangular FibroCartilage Complex Scaphoid fractures 20

12/1/2017 MRI with contrast -Gadolinum  Intra-articular contrast  Distends the joint  Enable evaluation of ligament and labrum  Hip and shoulder labral tears  Meniscus repairs  Cartilage injuries, such as TFCC MRI- Gadolinum  Intravenous contrast  Evaluate vascularity  Tumor  Post-surgical changes, such as scar tissue  Concern with kidney insufficiency and complications  Usually ordered by specialists 21

12/1/2017 MR arthrogram – elbow  Evaluate ligament tear  Evaluate OCD stability Look for intraarticular problems MCL tear Loose bodies, OCD MR arthrogram - wrist  Evaluate ligament tears  Look for communication between compartments 22

12/1/2017 Radiology Reports – love adjectives!  Fraying vs Partial tear vs Full thickness tear vs Retracted tear  Cartilage inhomogeneity vs fissure vs flap vs unstable flap vs full thickness cartilage loss  Tendon degeneration vs tendinosus vs tear Clinical Correlation Recommended What are they saying? CLINICAL HISTORY: 55 yo Posterior shoulder pain x1 year. Denies trauma.  There is adequate distention of the glenohumeral joint with intra-articularly  administered contrast. High T2 signal in the anterior subcutaneous fat compatible with iatrogenic injection of anesthetic. OSSEOUS ACROMIAL OUTLET: There is mild osteoarthrosis at the  acromioclavicular joint with fluid in the joint and capsular hypertrophy.. The acromion is type 1 on sagittal imaging. There is no evidence of os acromiale. There is no Thickening of the coracoacromial ligament. ROTATOR CUFF MUSCLES AND TENDONS:  Mild tendinosis of the supraspinatus tendon and anterior fibers of the  infraspinatus tendon. Possible limited interstitial tearing of the posterior fibers of the infraspinatus tendon at the insertion (series 6, image 13). Normal signal and morphology of the subscapularis and teres minor tendons.  Normal signal and bulk of the rotator cuff muscles.  LABRAL AND CAPSULAR STRUCTURES: Irregularity of the anterosuperior  and superior labrum compatible with degenerative changes. Blunting of the anterior labrum without discrete tear. No paralabral cyst formation. 23