Osteomyelitis: Always a Diagnostic Puzzle page 1 of 8 : Put the Pieces Together

Osteomyelitis HISTORY Clinical RADIOGRAPHS Always a Diagnostic Surgical Recent CT Puzzle Chronic MRI Active

©Ken L Schreibman, PhD/MD 2009 schreibman.info schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

Osteomyelitis: Topics Osteomyelitis: Definitions Definitions Model “Osteomyelitis ” comes from Greek: Active  osteon = bone Chronic  myelos = marrow  itis = inflammation Mechanisms Cortex “Inflammation of bone marrow” Hematogenous Infection of bone marrow Direct spread High Sensitivity Imaging Marrow MRI Low Specificity Radiographs Marrow Marrow inflammation from infection looks MRI like inflammation from any other cause ©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

Osteomyelitis: Definitions Osteomyelitis: Definitions Active Osteomyelitis Active Osteomyelitis vs “Aggressive” Chronic Osteomyelitis Resembles Tumor Cortex Destruction 

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©Ken L Schreibman, PhD/MD 1/30/10 www.schreibman.info Osteomyelitis: Always a Diagnostic Puzzle page 2 of 8 16yoM distal fibula pain Active Osteomyelitis 3w after inversion injury Osteomyelitis: Definitions “Aggressive” Chronic Osteomyelitis Cortex Destruction “Non-Aggressive” RADIOGRAPHS Periosteal Reaction Resembles Callus Active ≠ Chronic 3 Characteristics: : “wrap” HISTORY Thick periosteum around infected bone : “set apart” Clinical Followup Piece of dead, infected, bone Cloaca: “sewer” Opening in cortex through which pus can escape ©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

16yoM distal fibula pain Active vs Chronic Osteomyelitis Active Osteomyelitis 3w after inversion injury “Aggressive” Cortex Destruction Active RADIOGRAPHS Chronic Active Osteomyelitis Active ≠ Chronic Osteomyelitis Periosteal Reaction Osteomyelitis

©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

19yoM fibula pain 19yoM fibula pain Chronic Osteomyelitis 2.5years later… Chronic Osteomyelitis 2.5years later… CT Tibia RADIOGRAPHS Chronic Chronic Active ≠ Chronic Osteomyelitis Involucrum Osteomyelitis Fibula

2.5 years Sequestrum

Cloaca

©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

©Ken L Schreibman, PhD/MD 1/30/10 www.schreibman.info Osteomyelitis: Always a Diagnostic Puzzle page 3 of 8 27yoM s/p removal Chronic Osteomyelitis 42yoM Diabetic Chronic Osteomyelitis Rt Femoral Rod Involucrum Developing Involucrum

6 weeks later 10 more weeks CT Scout ©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

27yoM s/p removal 27yoM s/p removal Chronic Osteomyelitis Rt Femoral Rod Chronic Osteomyelitis Rt Femoral Rod Involucrum Involucrum Sequestrum Sequestrum Cloaca

Axial Slice Axial Slice

CT Scout Coronal Reformat CT Scout Oblique Coronal ©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

52yoM

Osteomyelitis: Mechanisms Decubitus Ulcer  Ischium quadriplegic Direct Spread  adjacent tissues Most common cause Decubitus ulcer Septic arthritis PUS T1

 Ischium Ischium 

T1 ©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

©Ken L Schreibman, PhD/MD 1/30/10 www.schreibman.info Osteomyelitis: Always a Diagnostic Puzzle page 4 of 8 Osteomyelitis: Mechanisms Ring Sequestrum Direct Spread  adjacent tissues Chronic Osteomyelitis Most common cause Involucrum Decubitus ulcer Sequestrum Septic arthritis Cloaca Puncture into bone Poor Union Stepped on nail External fixator Ring sequestrum

RADIOGRAPHS

©Ken L Schreibman, PhD/MD 2009 schreibman.info

Osteomyelitis: Mechanisms Hematogenous Osteomyelitis Direct Spread  adjacent tissues Site related to patient age Most common cause Decubitus ulcer Epiphysis

Physis Septic arthritis Venule

Puncture into bone Metaphysis

Stepped on nail Arteriole External fixator Infection Infection Ring sequestrum occurs at Septic occurs Diaphysis metaphysis Emboli at end Hematogenous of of Immature Blood Mature Site related to patient age Bone Supply Bone ©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

1yoM strep 1yoM strep Hematogenous Osteomyelitis pneumonia Hematogenous Osteomyelitis pneumonia 3 months later

©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

©Ken L Schreibman, PhD/MD 1/30/10 www.schreibman.info Osteomyelitis: Always a Diagnostic Puzzle page 5 of 8 Osteomyelitis: Imaging Osteomyelitis: What to Order When Many Imaging Options:  Radiographs ………… ALWAYS! Radiographs May show evidence of active infection vs Bone destruction, periosteal reaction CT May show evidence of chronic infection MR Involucrum Screen for metal US Orthopedic hardware, foreign bodies Nuc Med Unexpected findings What to order when? Fractures, gas in soft tissues Delineate current anatomy Surgical resections, neuropathic deformity RADIOGRAPHS NEED TO BE RECENT ©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

Need for Recent Radiographs Example Osteomyelitis: What to Order When Normal 66yoMNeuropathic h/o Diabetes destruction Radiographs ………… ALWAYS! Lisfranc joint Presentsof the Lisfranc in Sept swollen joint foot CT……………………. Chronic Cases MR is requested to “r/o Osteo” CT best for calcified structures Involucrum Are there radiographs? Sequestrum Yes Cloaca …3 months ago CT of the extremities is insensitive for: Bone marrow pathology Repeat radiographs obtained Soft tissue pathology now, prior to MR, reveal… June September

©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

Osteomyelitis: What to Order When Osteomyelitis: MR Imaging Radiographs ………… ALWAYS! Bone Model CT……………………. Chronic Cases MRI..…………………. Active Cases Marrow Marrow Marrow Shows extent of soft tissue edema Cortex Cortex Cortex Excellent for demonstrating abscesses

and other drainable fluid collections

Tissues (fat) Sensitive for bone marrow pathology Tissues (fat) Can be overly sensitive at expense of specificity Infected bone marrow resembles

marrow edema due to other causes

Surrounding Surrounding

T1 T2fs X-rays ©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

©Ken L Schreibman, PhD/MD 1/30/10 www.schreibman.info Osteomyelitis: Always a Diagnostic Puzzle page 6 of 8 Osteomyelitis: MR Imaging Osteomyelitis: MR Imaging   Path=Fluid    T1=Dark T2=Bright Enhancement T1fs+Gd Inflamed Enhancement  Uniform  Inflamed Abscess  Uniform  Wall  Abscess Cyst  Wall  Not (STIR)  Cyst (STIR) T1fs T1 T2fs  Not T1 T2fs +Gd ©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

63yoM Diabetic Osteomyelitis: MR Imaging Osteomyelitis: MR Imaging with heel ulcer Detection of the non-enhancing pus pocket (abscess) is crucial Presence of soft tissue abscess proves the edema in underlying Intact cortex T1 bone marrow is osteomyelitis. Minimal Enhancing cellulitis Site for aspiration for culture. Marrow No non-enhancing If IV Gd doesn’t get into abscess, Edema abscess pocket IV antibiotics won’t get in either, T1fs abscess may require drainage. IR IVGd ©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

63yoM Diabetic 63yoM Diabetic Osteomyelitis: MR Imaging 2 weeks later… Osteomyelitis: MR Imaging 2 weeks later… 2 weeks earlier 2 weeks earlier  

Cortical Cortical Intact cortex destruction Intact cortex destruction More marrow edema Non-enhancing Marrow edema More tissue edema abscess pocket Abscess Pocket

T1fs T1fs IR IVGd T1 IR IVGd ©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

©Ken L Schreibman, PhD/MD 1/30/10 www.schreibman.info Osteomyelitis: Always a Diagnostic Puzzle page 7 of 8 52yoM 1yoF Swollen

Decubitus Ulcer  Ischium quadriplegic Osteomyelitis: MR Imaging left lower leg R L Periosteal Reaction

Abscess!  T1fs  T1 +Gd

Metaphyseal  Abscess?  lucency T2fs ©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

1yoF Swollen Osteomyelitis: MR Imaging left lower leg Osteomyelitis: What to Order When Radiographs ………… ALWAYS! CT……………………. Chronic Cases Periosteal Reaction MRI..…………………. Active Cases US……….…………… Fluid/Abscess US guided aspiration for culture Cannot assess bone involvement Nuc Med.……………. Problem Cases Non-enhancing Metaphyseal Where MR specificity is decreased abscess Neuropathic feet Intra-osseous Infected hardware T1fs T1 T2fs IVGd ©Ken L Schreibman, PhD/MD 2009 schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

Infection around metal: MRI Infection around metal: Nuc Med T2fs T1fs Requires 2 Radiopharmaceuticals IVGd We can see Enhancing 1)Tc-Bone Scan (Active bone metabolism) soft tissues granulation tissue 2)In-WBC Scan around bone (phlegmon?) (Areas of WBC accumulation)

1)BS: Sen/Spec 2)WBC:Spec/Sen We can’t see the marrow within bone Cannot evaluate for “osteomyelitis” ©Ken L Schreibman, PhD/MD 2009 T,K 21yoM schreibman.info ©Ken L Schreibman, PhD/MD 2009 schreibman.info

©Ken L Schreibman, PhD/MD 1/30/10 www.schreibman.info Osteomyelitis: Always a Diagnostic Puzzle page 8 of 8 Infection around metal: Nuc Med Charcot (Neuropathic) Foot Femur Tc-Bone Scan In-WBC Scan Removed T1T1fs T2fs Plate Tibia Plate +IV Gd Abscess

Femur Femur

Tc 99m MDP In111 WBC

Tibia Tibia Placed Antibiotic Infection Tibia PMM-Beads Plate ©Ken L Schreibman, PhD/MD 2009 S,B 31yoM schreibman.info ©Ken L Schreibman, PhD/MD 2009 P,K 65yoF schreibman.info

Osteomyelitis: Put the Pieces Together

HISTORY

Clinical RADIOGRAPHS Surgical Recent CT Chronic MRI Active

©Ken L Schreibman, PhD/MD 2009 schreibman.info

©Ken L Schreibman, PhD/MD 1/30/10 www.schreibman.info