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Quantitative angioscopy: a novel method of measurement of luminal dimensions during angioscopy with the use of a
1Cardiac Laser Laboratory, Wayne State University School of Medicine, Detroit, MI 48201.
Purpose:
To determine the accuracy and reproducibility of luminal dimension measurements of a newly developed method of quantitative angioscopy.
Methods:
A method was developed for quantitation of luminal dimensions during angioscopy, as variation in magnification with lens-object distance and ambiguity associated with identification of corresponding points about the circumference of a given discrete cross-section render subjective estimates unreliable. A transverse ring of fiberoptically transmitted light was emitted from a guidewire or its housing at a known distance from the distal end of an angioscope and discrete cross-sections of interest were observed as the ring of light was reflected from the luminal surface. Caliper measurement of the diameter of the light ring image (< 50 mW at 488/515 nm), obtained on angioscopic video recordings of cylindrical phantom vessels of known dimensions, was performed by three observers on five occasions.
Results:
The mean absolute difference between measured and known luminal diameter (n = 405 observations) was 65 microns +/- 35 microns and the mean coefficient of variation was 4.2%, and the mean difference between measured and known areas (n = 195 observations) was 0.4 mm2, with a mean coefficient of variation of 6.5%.
Conclusion:
By use of this new lightwire method, luminal dimensions can now be measured in vitro with a high degree of accuracy and reproducibility during angioscopy.