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Non-invasive method for detecting deep venous thrombosis in the human body

  • US 5,282,467 A
  • Filed: 08/13/1992
  • Issued: 02/01/1994
  • Est. Priority Date: 08/13/1992
  • Status: Expired due to Term
First Claim
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1. A non-invasive method for detecting deep venous thrombosis in a human body, said method comprising the steps of:

  • (a) securing an inflatable cuff to a body limb of interest wherein said body limb comprises skin, tissues, oxyhemoglobin and deoxyhemoglobin;

    (b) attaching a radiation source and operatively associated photodetector to the body limb proximate to said inflatable cuff;

    (c) actuating said radiation source so that radiation penetrates through the skin and into the deep venous system of the body limb to enable detecting of changes in the amount of deoxyhemoglobin in said deep venous system;

    (d) effecting changes in the amount of deoxyhemoglobin in the body limb by inflating said cuff during said radiation source actuation to a pressure below arterial pressure to trap blood in the venous system for a determining a time period and by deflating said cuff during said same radiation source actuation;

    (e) actuating said photodetector to detect changes occurring during the trapping of the blood in the venous system after said cuff is inflated and during the emptying of the venous system after said cuff is deflated by measuring reflectance contributions including contribution from the skin, tissues, oxyhemoglobin and deoxyhemoglobin of the body limb; and

    (f) detecting the presence of deep venous thrombosis by subtracting the reflectance contributions of the skin, tissues and oxyhemoglobin from the reflectance contribution of the deoxyhemoglobin and comparing the reflectance contribution of the deoxyhemoglobin to predetermined reflectance values for a normal body limb.

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