Osteomyelitis: Always a Diagnostic Puzzle page 1 of 8 Osteomyelitis: 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 Bone 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 Periosteal Reaction
©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 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: Involucrum: “wrap” HISTORY Thick periosteum around infected bone Sequestrum: “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 Brodie Abscess 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