Diabetes-Related Foot Pathology High morbidity Lifetime ulcer risk - - PowerPoint PPT Presentation

Diabetes-Related Foot Pathology

 High morbidity  Lifetime ulcer risk for diabetics 25%  Nearly all diabetes-related foot infection

secondary from ulcer

Nothing To Disclosure

MRI Sensitivity & Specificity Osteomyelitis of Diabetic Feet

 1995 (no Gd): 82% sensitivity, 80% specificity  1997 (with Gd): 90% sensitivity, 70% specificity

 no effect of Gd (disputes earlier data)

 2007 (no Gd): 90% senisitivity, 83% specificity

MRI Primary Findings

 Marrow signal (HIGH STIR/T2 & LOW T1)*  Gd Marrow enhancement  Ulcer or sinus tract leading to bone with abnormal

marrow signal

 Presence of abscess

MRI Secondary Signs

 Cellulitis  Foreign body  Periosteal reacton

Osteomyelitis vs. Neuropathic Charcot

 Marrow signal change  Single bone  Diffuse infiltration  Minimal deformity  Ulcer, sinus tract, abscess  Wgt. bearing: fore/hind

foot

 Marrow signal change  Multiple bones  Periarticular &

subchondral

 Deformity with bone

debris

 Edema but intact skin  Non-wgt. bearing:

midfoot

Osteomyelitis Neuropathic Charcot

Location, Location, Location

 Neuroarthopathy (Charcot)--MIDFOOT:

 Tarsal-Tarsal  Tarsometatarsal (TMT)

 Osteomyelitis FORE & HINDFOOT:

 Distal to tarsometatarsal  Calcaneus  Malleoli

Distal phalangeal osteomyelitis

Low T1 signal

Distal phalangeal osteomyelitis

High T2 signal

Distal phalangeal osteomyelitis

Gd enhancement

Metatarsal head osteomyelitis with sinus tract

Forefoot osteomyelitis with contiguous abscess

Abscess and Osteomyelitis

 20% of osteomyelitis are + for soft tissue abscess  100% correlation with osteomyelitis (same as sinus

tract)

 Abscess more common in post surgical foot  50% of all abscesses in fore foot and are directly

contiguous

 Mid/Hind foot abscess may be remote from site of

• steomyelitis

Calcaneus osteomyelitis with sinus tract and abscess

Osteomyelitis with intramedullary bone abscess of talus

Osteomyelitis: confluent, geographic medullary distribution

No osteomyelitis: Ulcer with minimal subcortical T1/T2 signal

Osteomyelitis: ulcer with confluent abnomal T1 signal

No osteomyelitis: T1 “hazy” pattern

No osteomyelitis: T1 reticulated pattern

Neuropathic arthropathy of midfoot

Neuropathic arthropathy of midfoot

Neuropathic arthropathy with superimposed osteomyelitis

Bone Biopsy

 For histological proven osteomyelitis, positive rate of

percutaneous biopsy:

 50%  42%  34% (largest study)

Bone Biopsy

 Aspiration of > 2cc’s purulent fluid—83% positive

• steomyelitis rate.

 Risk of seeding uninfected tissue.  Utility of identifying an organism?