Download DONNA MAGID, MD, MEd DIRECTOR, JHU SOM RADIOLOGY

Introduction to MSK
Imaging Studies:
“Don’t Panic”
Donna Magid, MD, M.Ed
Director, Horizontal Strand in Diagnostic Imaging
Professor, Radiology, Orthopaedic Surgery, and
Functional Anatomy and Evolution
Objectives
Introductory concepts of MSK Imaging
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‘REQUESTING’ vs ‘ORDERING’ studies
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Sequencing MSK studies: what to do when
ACR Appropriateness Criteria to the rescue!
Give you life-long fishing skills rather than handing over fish.
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Common errors:
Forgetting “One view is no view”
Skipping usual steps
Not reviewing older studies
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Pro/cons of common imaging modalities:
XR, CT, MR, US
YOU: Intelligent Consumers
of Medical Resources (not optional)
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Common indix. head CT = “R/o stroke, dizzy”
Legitimate concern for stroke (but overinclusive).
Inner-ear-pt. subset: benign, conservative tt.
Better clinical ED screen for benign ear
etiologies could reduce CT in US by
$500 million/year.
Newman-Toker et al, Academic Emergency Medicine July 2013
“ Intelligent Consumer” may
mean NOT utilizing imaging
(unnecessarily…$, dose)
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ED(USA) 2006: 34% radiographed (more, JHH)
12% CT
Pitts, Niska et al National Health Statistics report (7)2006
CT tripled, 19962010
Smith-Bindeman, JAMA June 2012
“KISS” : Import old studies! Outside studies reduce new by:
17% overall
CT: 29%
Sodickson, Opraseuth, Ledbetter; RADIOLOGY 2011:260 (2)
Remember one does not ‘ORDER an exam’,
one ‘REQUESTS a CONSULT’
Consulting Radiologist needs info. to confirm:
 Correct study requested
 Correct Pt.
 Meds, allergies, status, caveats
 Cost/benefit ratio favors the patient:
Risk, dose, pain, complications, sometimes $$
‘Will it alter management?’ If not—NO!
DNR, religious beliefs, life expectancy…
Info already known or available (old images)
The Imaging Requisition
Electronic, faxed, written….. Varies, morphs often
Pt. Name – MRN – DOB – Location (wrist band, paperwork, chart)
Deal-breakers = Misspelling, mismatches
 Contact/Requesting Clinician, ACCURATE phone, page:
Questions before test performed
URGENT findings, emergencies
 Females of child-bearing age (~9 to 90): Pregnancy status
 Known allergies
 Known caveats or contraindications (dialysis stent, implants,
metal, 1 day post-op, deaf, non-English speaking…)
Imaging Request asks a question
“Worry/Don’t Worry”
 “Normal/Abnormal” (old images!)
 “Better/Worse” (size, radiodensity, signal, fluid…)
 “Bigger/Smaller/Unchanged”
 Narrow or confirm initial DDx
 Better localize a finding (in 3D, organ, tissue, …)
 Better characterize a finding (cystic, solid,…)
Requistion: Clinical Info
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Concise and Precise (“G.I.G.O.”)
“Fx”,“R/O”,“Pain”,“Fell” … inadequate!
Localize with ONE finger
Describe mechanism/force if trauma:
“MVC”
“Belted passenger, T-boned on R high veloc.’
or ”Pedestrian, struck laterally in parking lot,
landed on/pain R hip”
vs
Time frame: new; older; chronic
‘Today…5 days ago…4 months…..5 years……’
Give us adequate info and query,
not a protocol
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Clinical info, DDx, concerns, clues, labs, query
Let us protocol the technical details of exam
Let us decide on which machine (esp. CT, MR)
CT: “R/O intracranial bleed, fell 8 ft, LOC”,
not just “Dry head CT, reformats” w/o clinical info
MR: “Adenoca lung, confusion, R/O brain mets”;
not ‘T1, T2, brain w/, w/o, contrast”, no other info
INTRODUCTORY MSK
IMAGING: ‘Don’t Panic’
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Musculoskeletal Imaging:
Bones (cortical, articular, marrow, physis)
Joints (cartilage, ligament, tendon, fluid)
Ligaments, Tendons (XR, MR)
Cartilage (articular, meniscal, fibro-: XR, MR, CT,)
Soft tissue (muscle, fascia, fat: XR, CT, MR, US)
Vascular (vessels, blood supply: XR,CT, MR, US)
Neurography (MR)
MSK Imaging: cost/benefit
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Pediatric vs Adult (hip, appx, brain:
Fertility, Life expectancy
DDx (differential diagnosis)
Trauma
Infectious/inflammatory
Neoplastic
Vascular
Iatrogenic
Arthritis, connective tissue
Metabolic
Developmental/congenital/genetic
Normal or Nl. Variant
US v CT)
MSK Imaging Tx- and Dx-Specific
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DDx (differential diagnosis)
Trauma (acute, chronic, velocity or force)
Infectious/inflammatory (acute, chronic, immunocomp.)
Neoplastic (new, treated, recurrent)
Vascular
Iatrogenic (surgery, foreign matter, Rx)
Arthritis, connective tissue
Metabolic
Developmental/congenital/genetic
Give us adequate info, query;
not a protocol
Imaging techniques, equipment,
changing rapidly.
Unlikely a non-Radiologist can
keep up; even Radiologists
are scrambling.
On-line Mind Palaces….
Modalities: ‘First Things First’
Short-cuts counterproductive
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RADIOGRAPHY (conventional images) remains
the gateway to (MSK) imaging assessment.
It is NOT going away.
XR plus Time may still
Trump Tissue, MR, CT
RADIOGRAPHY:
“One View Is No View”
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Once a study indicated – no shortcuts.
Not for age, gender, cost, dose…….
Many findings underwhelm on one view
Complex 3D structures need 2 Views
Fractures, Dislocations
Toddler’s Fracture
Slipped Capital Femoral Epiphysis
CT vs MR:
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CT: Rapid (7 seconds)
movement, cooperation
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pro/com
MR: No radiation
Contrast rxn. v. rare
Superb soft tx. info.
Freely reformattable
Windows ex post facto
Superb resolution
“WYSIWYG” per sequence
Contrast rxn. rare
Much slower (45-90 min)
Metal can be imaged Claustrophobic
Metal = abs. contraindx, 2x
High-dose radiation
Less resolution
Metal can degrade image Expensive (~2x CT)
Expensive but ~$1/2 MR Weight, size limits: both
CT vs MR: What is the Question?
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CT: “4 Bs” radiodense
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MR:
Soft tx– ligament, muscle,
Bone
tendon, cartilage,
Blood (acute hemorrhage)
muscle, neural, tumor
Bullets and metal
Molecular differences
Barium (ie contrast)
Better soft tissue detail
Lung and chest
Direct multiplanar
Cancer staging
Speed overcomes motion Non-polar materials not visualized
ie, bone (calcium).
<-- CT
MR 
CT
MR
US: When and Where?
MSK: Currently limited in adults; rapidly changing
PRO:
CON:
 Portable
 Fat, bone, air, metal,
Safe (no dose no risk),
all block US
Far less expensive
 Low resolution
 GYN, Doppler flow
 Highly user-dependent
 Echocardiograph
 Non-intuitive (‘weather maps’)
 RUQ abdomen
 Bx, line placement,‘taps’
(pleural, abscess, joints)
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DVT: proximal extremities
Breast: cyst vs solid
US: Soft tissue, Flow
Barriers: Bone, Fat, metal, air…
Rheumatoid arthritis.
Gutierrez M et al. Ann Rheum Dis 2011;70:1111-1114
©2011 by BMJ Publishing Group Ltd and European League Against Rheumatism
ACR AC
American College of Radiology Appropriateness Criteria
www.acr.org
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Evidence-based guidelines to choose imaging
200 Dx with 900 scenarios/variants; referenced
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Relative Radiation Risk each study
Modality guidelines CT, MR, US, Nucs, PET,…
Practice Guidelines: When (in what order) to perform:
Radiography, CT, MR of the extremities
Spine Radiography, CT, MR
Scoliosis radiography
(Portable chest, Abdominal radiography, hysterosalpingograms,
Dxc Ct, Pediatric CT, Ct colonoscopy, MR knee, MR brain, US, …)
Varied Clinical Scenarios per DDx
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200 Dx with 900 variants (modifiers); eg:
Blunt Chest Trauma: 3 variations per clinical/XR
Acute hip pain, suspected fx.: 2 variations, 4 pgs discussion
Acute shoulder pain
Chronic wrist pain
Chronic neck pain
Imaging after arthroplasty (joint replacement)
Non-traumatic knee pain
Soft tissue masses
Suspected avascular necrosis
“Acute Shoulder Pain”
Initial =s XR, then branches into detailed specifics
 Acute shoulder pain (leave choice of initial XR views to us)
‘Any etiology, initial study’: XR=9(best); CT, MR, US=1(worst)
‘XR neg, significant persistant pain’ MR (9); CT (5)
‘XR neg, under 35, suspect labral tear’ MR arthrog(9), MR(7), CT(5)
‘XR neg, prior rotator cuff repair, suspect re-tear ‘ MR (9) w. or w/o
‘XR neg, suspect septic arthritis’  arthrocentesis (9), MR w&w/o (7)
 Jumping straight to sophisticated imaging = mistake.
 Short-cuts, ‘time-savers’, pervert accurate diagnosis.
 Radiography (‘plain film”) NOT going away!
“LOW BACK PAIN”
80% of over-45 yo
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“Uncomplicated, no red flags(explained)”: All imaging = ‘2’
‘With radiculopathy, surg. candidate” MR w/o (8); CT (5)
“Low-veloc trauma, osteoporosis, focal/progressive
deficit, prolonged sx, or >70 yo”  XR then MR
“Possible cancer, infection, and/or known
immunosuppression” -> MR w&w/o (8); MR w/o (7); CT(6);
“Prior lumbar surgery”  MR w&w/o (8); MR w/o (6) CT (6)
By the time you straighten this out…
Standard of Care (SOC) may have changed again
EPIPHANY: One need not understand
physics to request proper exam
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Understand what each modality can/cannot do, not
‘why’, nor ‘how’.
Use resources– ACR AC, Radiologists– to confirm
appropriate next-step.
RESOURCES constant, ANSWERS change often.
Commonly used studies will become familiar.
Less-common….won’t. Don’t worry.
ASK US!
http://3rads.jhmi.edu/
All imaging phone numbers
When to use contrast, what study to get,
can be counter-intuitive and subtle.
 Include us on the patient care team; we are
CONSULTANTS, not lab techs.
 On-call techs, all modalities/subspecialties:
use 3Rads.jhmi.edu
Back-up: ask Emed Radiology Resident 7-5442
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Dxc. Imaging: TTW 2014
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“REPETITION IS THE KEY TO LEARNING”
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Intro to Chest Radiographs:
The Ur-unit of imaging
Thank you!
Donna Magid, MD, M.Ed