title: Infrared imaging of subcutaneous veins.
abstract: OBJECTIVE
  Imaging of subcutaneous veins is important in many applications, such as gaining venous access and vascular surgery. Despite a long history of medical infrared (IR) photography and imaging, this technique is not widely used for this purpose. Here we revisited and explored the capability of near-IR imaging to visualize subcutaneous structures, with a focus on diagnostics of superficial veins.
  
  
  METHODS
  An IR device comprising a head-mounted IR LED array (880 nm), a small conventional CCD camera (Toshiba Ik-mui, Tokyo, Japan), virtual-reality optics, polarizers, filters, and diffusers was used in vivo to obtain images of different subcutaneous structures. The same device was used to estimate the IR image quality as a function of wavelength produced by a tunable xenon lamp-based monochrometer in the range of 500-1,000 nm and continuous-wave Nd:YAG (1.06 microm) and diode (805 nm) lasers.
  
  
  RESULTS
  The various modes of optical illumination were compared in vivo. Contrast of the IR images in the reflectance mode was measured in the near-IR spectral range of 650-1,060 nm. Using the LED array, various IR images were obtained in vivo, including images of vein structure in a pigmented, fatty forearm, varicose leg veins, and vascular lesions of the tongue.
  
  
  CONCLUSIONS
  Imaging in the near-IR range (880-930 nm) provides relatively good contrast of subcutaneous veins, underscoring its value for diagnosis. This technique has the potential for the diagnosis of varicose veins with a diameter of 0.5-2 mm at a depth of 1-3 mm, guidance of venous access, podiatry, phlebotomy, injection sclerotherapy, and control of laser interstitial therapy.
authors.affiliation: Philips Classic Laser Biomedical Laboratory, University of Arkansas for Medical Sciences, 4301 West Markham Street, Slot 543, Little Rock, AR 72205-7199, USA. ZharovVladimirP@uams.edu
authors.forename: Vladimir P
authors.initials: VP
authors.lastname: Zharov
authors.forename: Scott
authors.initials: S
authors.lastname: Ferguson
authors.forename: John F
authors.initials: JF
authors.lastname: Eidt
authors.forename: Paul C
authors.initials: PC
authors.lastname: Howard
authors.forename: Louis M
authors.initials: LM
authors.lastname: Fink
authors.forename: Milton
authors.initials: M
authors.lastname: Waner
mesh_terms: D005542:Forearm / Q000098:blood supply; D006801:Humans; D007259:Infrared Rays; D053685:Laser Therapy; D012867:Skin / Q000098:blood supply*; D014648:Varicose Veins / Q000175:diagnosis; D014680:Veins