Perfusion Estimation
1. ABI
Method
- use doppler US & BP cuff
- systolic BP at ankle & arm
- ABI = Ankle / Brachial
Normal Range
.9 – 1.3
Measurement in DM
- may be falsely elevated due to calcification of media
- “trusted when low but not high”
- <.9 suggestive of PVD
- <.7 severe PVD
2. Transcutaneous O2 Measurement (TcPO2)
Measured by electrode placed on warmed foot
- affected by oedema/ infection / neuropthy
- <25 mmHg = unlikely to heal
3. Toe Blood Pressure
Measured by plethysmography
- >30 mmHg = good wound healing potential
- Less sensitive / specific than TcPO2
Angiogram
If foot pulses are absent / asymmetric
Osteomyelitis Imaging
1. X-Ray
- may not show changes in early stages (<14 days)
- later Stages - Triad– Osteolysis, periosteal reaction, bone destruction
2. MRI
Most sensitive imaging for diabetic foot infections
Findings
- bone oedema
- abscesses (Low Signal T1; Gad Ring enhancement)