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©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis
Always a Diagnostic Puzzle
schreibman.info
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: Put the Pieces Together
MRIActive
RADIOGRAPHSRecent
HISTORY
ClinicalSurgical
CTChronic
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: TopicsDefinitionsActiveChronic
MechanismsHematogenousDirect spread
ImagingRadiographsCTMRI
Bone Model
Cortex
Marrow
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: Definitionscomes from Greek:
osteon = bone myelos = marrow itis = inflammation
“Inflammation of bone marrow”Infection of bone marrow
MRIMarrow
High SensitivityLow Specificity
Marrow inflammation from infection looks like inflammation from any other cause
“Osteomyelitis”
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: DefinitionsActive Osteomyelitis
vsChronic Osteomyelitis
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: DefinitionsActive Osteomyelitis“Aggressive”Resembles Tumor
Cortex DestructionPeriosteal Reaction
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Active Osteomyelitis 16yoM distal fibula pain 3w after inversion injury
HISTORY
Clinical Followup
“Aggressive”Cortex DestructionPeriosteal Reaction
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: DefinitionsChronic Osteomyelitis“Non-Aggressive”Resembles Callus3 Characteristics:
Involucrum: “wrap”Thick periosteum around infected bone
Sequestrum: “set apart”Piece of dead, infected, bone
Cloaca: “sewer”Opening in cortex throughwhich pus can escape
RADIOGRAPHSActive ≠ Chronic
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Active vs Chronic Osteomyelitis
RADIOGRAPHSActive ≠ Chronic
ActiveOsteomyelitis
ChronicOsteomyelitis
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Active Osteomyelitis“Aggressive”Cortex DestructionPeriosteal Reaction
16yoM distal fibula pain 3w after inversion injury
ActiveOsteomyelitis
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Chronic Osteomyelitis 19yoM fibula pain2.5years later…
2.5 years
ChronicOsteomyelitisRADIOGRAPHS
Active ≠ Chronic
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Chronic Osteomyelitis 19yoM fibula pain2.5years later…
ChronicOsteomyelitisInvolucrum
Sequestrum
Cloaca
CT
Fibula
Tibia
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Chronic Osteomyelitis
6 weeks later
Involucrum Developing 42yoM Diabetic
10 more weeks
©Ken L Schreibman, PhD/MD 2010 schreibman.info
27yoM s/p removalRt Femoral RodChronic Osteomyelitis
Involucrum
27yoM s/p removalRt Femoral Rod
CT Scout
©Ken L Schreibman, PhD/MD 2010 schreibman.info
27yoM s/p removalRt Femoral RodChronic Osteomyelitis
InvolucrumSequestrum
27yoM s/p removalRt Femoral Rod
CT Scout
Axial Slice
Coronal ReformatCoronal Reformat
©Ken L Schreibman, PhD/MD 2010 schreibman.info
27yoM s/p removalRt Femoral RodChronic Osteomyelitis
InvolucrumSequestrumCloaca
27yoM s/p removalRt Femoral Rod
CT Scout
Axial Slice
Oblique CoronalOblique Coronal
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: MechanismsDirect Spread adjacent tissuesMost common causeDecubitus ulcerSeptic arthritis
PUS
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Decubitus Ulcer Ischium
Ischium Ischium
T1
52yoMquadriplegic
T1
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: MechanismsDirect Spread adjacent tissuesMost common causeDecubitus ulcerSeptic arthritis
Puncture into boneStepped on nailExternal fixatorRing sequestrum
Ring SequestrumChronic Osteomyelitis
InvolucrumSequestrumCloacaPoor Union
RADIOGRAPHS
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: MechanismsDirect Spread adjacent tissuesMost common causeDecubitus ulcerSeptic arthritis
Puncture into boneStepped on nailExternal fixatorRing sequestrum
HematogenousSite related to patient age
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Hematogenous OsteomyelitisSite related to patient age
MatureBone
ImmatureBone
PhysisEpiphysis
Metaphysis
Diaphysis
Art
erio
leA
rter
iole Venule
BloodSupplyBloodSupply
SepticEmboliSepticEmboli
Infectionoccursat end
of
Infectionoccurs at
metaphysisof
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Hematogenous Osteomyelitis 1yoM streppneumonia
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Hematogenous Osteomyelitis 1yoM streppneumonia
3 months later
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: ImagingMany Imaging Options:RadiographsCTMRUSNuc Med
What to order when?
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: What to Order When………… ALWAYS!
May show evidence of active infectionBone destruction, periosteal reaction
May show evidence of chronic infection Involucrum
Screen for metalOrthopedic hardware, foreign bodies
Unexpected findingsFractures,
Delineate current anatomySurgical resections,
RADIOGRAPHS NEED TO BE RECENT
vs
RadiographsRadiographs
gas in soft tissuesgas in soft tissues
neuropathic deformityneuropathic deformity
©Ken L Schreibman, PhD/MD 2010 schreibman.info
66yoM h/o DiabetesPresents in Sept swollen footMR is requested to “r/o Osteo”
Are there radiographs?Yes
…3 months ago
Repeat radiographs obtained now, prior to MR, reveal…
Need for Recent Radiographs Example
June September
Neuropathic destruction of the Lisfranc joint
Normal Lisfranc joint
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: What to Order WhenRadiographs …………ALWAYS!CT……………………. Chronic
CasesCT best for calcified structures
InvolucrumSequestrumCloaca
CT of the extremities is insensitive for:Bone marrow pathologySoft tissue pathology
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: What to Order WhenRadiographs …………ALWAYS!CT……………………. Chronic
CasesMRI..…………………. Active Cases
Shows extent of soft tissue edemaExcellent for demonstrating abscesses
and other drainable fluid collectionsSensitive for bone marrow pathology
Can be overly sensitiveat expense of specificity
Infected bone marrow resembles marrow edema due to other causes
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: MR Imaging
T1 T2
Bone Model
X-rays
CortexMarrowMarrow
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: MR Imaging
T1 T2Surro
undi
ngSu
rroun
ding
Tissues (fat)Tissues (fat)
CortexMarrowMarrow
CortexMarrow
Surro
undi
ngSu
rroun
ding
Tissues (fat)Tissues (fat)
Bone Model
X-rays
CortexMarrowMarrow
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: MR Imaging
T1 T2fsSurro
undi
ngSu
rroun
ding
Tissues (fat)Tissues (fat)
CortexMarrowMarrow
CortexMarrow
Surro
undi
ngSu
rroun
ding
Tissues (fat)Tissues (fat)
Bone Model
X-rays
CortexMarrowMarrow
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: MR ImagingPath=FluidT1=DarkT2=BrightT1fs+GdEnhancement Inflamed Uniform
Abscess Wall
Cyst NotT1
(STIR)T2fs
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: MR Imaging
T1T1fs(STIR)
T2fs
+Gd
EnhancementInflamed UniformAbscess WallCyst Not
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: MR ImagingDetection of the non-enhancing pus pocket (abscess) is crucialPresence of soft tissue abscess
proves the edema in underlying bone marrow is osteomyelitis.
Site for aspiration for culture.If IV Gd doesn’t get into abscess,
IV antibiotics won’t get in either,abscess may require drainage.
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: MR Imaging 63yoM Diabeticwith heel ulcer
Arterial Ca++
T1
IR
Minimal Marrow Edema
T1fsIVGd
Enhancing cellulitisNo non-enhancing
abscess pocket
Intact cortex
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: MR Imaging 63yoM Diabetic2 weeks later…
Intact cortex
2 weeks earlier
Cortical destruction
IRT1fs
IVGd
More marrow edemaMore tissue edema
Non-enhancingabscess pocket
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Intact cortex
2 weeks earlier
Cortical destruction
Osteomyelitis: MR Imaging 63yoM Diabetic
2 weeks later…
T1T1fs
IVGdIR
Marrow edemaAbscess Pocket
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Decubitus Ulcer Ischium
T1
52yoMquadriplegic
T2fs
Abscess?
Abscess!T1fs+Gd
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: MR Imaging 1yoF Swollenleft lower leg
R L Periosteal ReactionPeriosteal Reaction
MetaphyseallucencyMetaphyseallucency
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: MR Imaging 1yoF Swollenleft lower leg
T1T1fs
IVGdT2fs
Periosteal ReactionPeriosteal Reaction
MetaphysealMetaphyseal Non-enhancing abscessIntra-osseous
Brodie AbscessBrodie Abscess
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: What to Order WhenRadiographs …………ALWAYS!CT……………………. Chronic
CasesMRI..…………………. Active CasesUS……….…………… Fluid/
AbscessUS guided aspiration for cultureCannot assess bone involvement
Nuc Med.……………. Problem CasesWhere MR specificity is decreased
Neuropathic feet Infected hardware
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Infection around metal: MRI
T,K 21yoM
T2fs T1fsIVGd
We can see soft tissues
around bone
We can see soft tissues
around bone
Enhancing granulation tissue
(phlegmon?)
Enhancing granulation tissue
(phlegmon?)
We can’t see the marrow within boneCannot evaluate for “osteomyelitis”
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Infection around metal: Nuc MedRequires 2 Radiopharmaceuticals
1)Tc-Bone Scan (Active bone metabolism)2)In-WBC Scan(Areas of WBC accumulation)
1)BS: Sen/Spec2)WBC:Spec/Sen
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Infection around metal: Nuc Med
FemurFemur
Tibia
Femur
Tibia
S,B 31yoM
Tc-Bone Scan In-WBC Scan RemovedTibia Plate
PlacedAntibiotic
PMM-Beads
PlacedAntibiotic
PMM-BeadsTibiaPlate
FemurPlate
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Charcot (Neuropathic) Foot
P,K 65yoF
T1 T2fsT1fs+IV Gd
Tc99m MDP In111 WBC
Abscess
Infection
©Ken L Schreibman, PhD/MD 2010 schreibman.info
Osteomyelitis: Put the Pieces Together
MRIActive
RADIOGRAPHSRecent
HISTORY
ClinicalSurgical
CTChronic