title: Use of HSI to measure oxygen saturation in the lower limb and its correlation with healing of foot ulcers in diabetes.
abstract: OBJECTIVE
  To explore the use of hyperspectral imaging (HSI) to predict healing of diabetic foot ulcers in patients with diabetes.
  
  
  METHODS
  We used a HSI technique that incorporated novel software to account for tissue scattering of light, and was validated using blood samples of varying oxygen saturation assessed by blood gas analysis. HSI was then performed on a population newly presenting with diabetic foot ulcers to a specialist clinic, and associations were sought with healing at 12 and 24 weeks.
  
  
  RESULTS
  The correlation between the results of HSI and blood gas analysis was strong (r = 0.994). A total of 43 patients (mean ± sd age 62.7 ± 12.2 years; 31 men, 12 women; 37 with Type 2 diabetes, six with Type 1 diabetes) with foot ulcers were included in the prospective clinical study and underwent HSI within 16 days of presentation. In all, 26 ulcers healed within 12 weeks and 28 within 24 weeks. There was a negative association between tissue oxygenation assessed by HSI at baseline and healing by 12 weeks (P = 0.009), and this was observed in both infected and non-infected ulcers. There was a significant positive correlation between oxygenation assessed by HSI and time to healing (P = 0.03). No correlations were observed at 24 weeks.
  
  
  CONCLUSIONS
  These findings suggest that HSI may predict healing in routine practice. The fact that the correlation between HSI and healing was negative could be explained by HSI being a measure of oxygenation of haemoglobin and there may be an inverse relationship between this and the oxygenation of extravascular tissue in people with neuropathy and/or microvascular disease.
authors: Foot Ulcer Trials Unit, Department of Diabetes and Endocrinology, Nottingham University Hospitals Trust, Nottingham, UK.
authors: W J
authors: WJ
authors: Jeffcoate
authors: Department of Medical Physics and Clinical Engineering, Nottingham University Hospitals Trust, Nottingham, UK.
authors: D J
authors: DJ
authors: Clark
authors: Department of Medical Physics and Clinical Engineering, Nottingham University Hospitals Trust, Nottingham, UK.
authors: N
authors: N
authors: Savic
authors: Department of Electrical and Electronic Engineering, University of Nottingham, Nottingham, UK.
authors: P I
authors: PI
authors: Rodmell
authors: Foot Ulcer Trials Unit, Department of Diabetes and Endocrinology, Nottingham University Hospitals Trust, Nottingham, UK.
authors: R J
authors: RJ
authors: Hinchliffe
authors: Foot Ulcer Trials Unit, Department of Diabetes and Endocrinology, Nottingham University Hospitals Trust, Nottingham, UK.
authors: A
authors: A
authors: Musgrove
authors: Foot Ulcer Trials Unit, Department of Diabetes and Endocrinology, Nottingham University Hospitals Trust, Nottingham, UK.
authors: F L
authors: FL
authors: Game
mesh_terms: D000368:Aged; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000378:metabolism / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000378:metabolism / Q000503:physiopathology; D017719:Diabetic Foot / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology*; D003952:Diagnostic Imaging / Q000379:methods*; D000067493:Dynamic Light Scattering; D005260:Female; D005528:Foot / Q000098:blood supply / Q000503:physiopathology; D006801:Humans; D035002:Lower Extremity / Q000098:blood supply* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology*; D014945:Wound Healing / Q000502:physiology*
chemical_list: D010100:Oxygen