Transcript 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
‘
REQUESTING
’
vs ‘ORDERING’ studies
Sequencing
MSK studies: what to do when ACR Appropriateness Criteria to the rescue!
Give you life-long fishing skills rather than handing over fish.
Common errors
: Forgetting “One view is no view” Skipping usual steps Not reviewing older studies Pro/cons of common imaging modalities: XR, CT, MR, US
YOU: Intelligent Consumers of Medical Resources (not optional)
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)
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
one ‘ REQUESTS
an exam’,
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
Concise and Precise (“G.I.G.O.”) “Fx”,“R/O”,“Pain”,“Fell” … inadequate!
Localize with ONE finger Describe mechanism/force if trauma: “MVC” vs or “Belted passenger, T-boned on R high veloc.’ ”Pedestrian, struck laterally in parking lot, landed on/pain R hip” Time frame : new; older; chronic ‘Today…5 days ago… 4 months …..
5 years……’
Give us
adequate info
and
not a protocol query,
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’
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
Pediatric vs Adult (hip, appx, brain: US v CT) Fertility, Life expectancy DDx (differential diagnosis) Trauma Infectious/inflammatory Neoplastic Vascular Iatrogenic Arthritis, connective tissue Metabolic Developmental/congenital/gene tic Normal or Nl. Variant
MSK Imaging
Tx- and Dx-Specific
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/gene tic
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
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”
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:
pro/com
CT :
Rapid (7 seconds) movement, cooperation Freely reformattable Windows ex post facto
MR :
No radiation Contrast rxn. v. rare Superb soft tx. info.
Superb resolution Contrast rxn. rare Metal can be imaged “WYSIWYG” per sequence Much slower (45-90 min) Claustrophobic Metal = abs. contraindx, 2x High-dose radiation Metal can degrade image Expensive (~2x CT) Expensive but ~$1/2 MR Less resolution
Weight, size limits: both
CT vs MR: What is the Question?
CT
: “4 Bs” radiodense Bone Blood (
acute
hemorrhage) Bullets and metal
MR
: Soft tx – ligament, muscle, tendon, cartilage, muscle, neural, tumor 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), Far less expensive
all block US Low resolution
GYN, Doppler flow
Highly user-dependent
Echocardiograph
Non-intuitive (‘weather maps’)
RUQ abdomen Bx, line placement,‘taps’ (pleural, abscess, joints) 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
Evidence-based guidelines
to choose imaging 200 Dx with 900 scenarios/variants; referenced
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
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
“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
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
Dxc. Imaging: TTW 2014
“REPETITION IS THE KEY TO LEARNING”
Intro to Chest Radiographs: The Ur-unit of imaging