1. A rapid, accurate, noninvasive technique for diagnosing critical and subcritical stenoses in aortoiliac arteries 
Alan P. Sawchuk, MD, MSEE, D.Preston Flanigan, MD, J.Chadwick Tober, MD, Darwin Eton, MD, MS, Thomas H. Schwarcz, MD, Jens Eldrup-Jorgensen, MD, Joseph P. Meyer, MD, Joseph R. Durham, MD, James J. Schuler, MD 
Journal of Vascular Surgery 
Volume 12, Issue 2, Pages (August 1990)
DOI: / (90)90104-I
Copyright © 1990 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

2. Fig. 1
An arterial bed is a “system” in engineering terminology. It can be characterized by appropriately comparing its input and output signals. One limb of the depicted arterial bed has a stenosis, and its flow pattern would be expected to be different from that of the normal limb.
Journal of Vascular Surgery  , DOI: ( / (90)90104-I)
Copyright © 1990 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

3. Fig. 2
A normal artery without a stenosis A has a different transfer function from an artery with a stenosis B.
Journal of Vascular Surgery  , DOI: ( / (90)90104-I)
Copyright © 1990 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

4. Fig. 3
A normal artery A may have the same femoral waveform as an artery containing a proximal stenosis B, but their transfer functions would be different.
Journal of Vascular Surgery  , DOI: ( / (90)90104-I)
Copyright © 1990 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

5. Fig. 4
The Mean Power Frequency Index (MPFI) is shifted to the left in an artery containing a proximal stenosis B compared to a normal artery A.
Journal of Vascular Surgery  , DOI: ( / (90)90104-I)
Copyright © 1990 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

6. Fig. 5
Schematic illustration of the equipment used for the noninvasive diagnosis of aortoiliac stenosis.
Journal of Vascular Surgery  , DOI: ( / (90)90104-I)
Copyright © 1990 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

7. Fig. 6
Scatter diagram of the individual Mean Power Frequency Indexes (MPFIs) for groups 1 through 3. There is minimal overlap between the groups.
Journal of Vascular Surgery  , DOI: ( / (90)90104-I)
Copyright © 1990 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

8. Fig. 7
Frequency spectrum or Fourier Transform (FT) representation of the flow in the aorta and femoral artery in a patient with a normal aortoiliac segment. The derived transfer function (TF) is also shown.
Journal of Vascular Surgery  , DOI: ( / (90)90104-I)
Copyright © 1990 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

9. Fig. 8
Frequency spectrum of Fourier Transform (FT) representation of the flow in the aorta and femoral artery in a patient with a subcritical aortoiliac stenosis. The derived transfer function (TF) is also shown.
Journal of Vascular Surgery  , DOI: ( / (90)90104-I)
Copyright © 1990 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

10. Fig. 9
Frequency spectrum or Fourier Transform (FT) representation of the flow in the aorta and femoral artery in a patient with a critical aortoiliac stenosis. The derived transfer function (TF) is also shown.
Journal of Vascular Surgery  , DOI: ( / (90)90104-I)
Copyright © 1990 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

11. Fig. 10
Transfer Function (TF) derived from a patient with a normal aortoiliac segment compared to that from a patient with an iliac artery occlusion.
Journal of Vascular Surgery  , DOI: ( / (90)90104-I)
Copyright © 1990 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions