Quantitative angioscopy: a novel method of measurement of luminal dimensions during angioscopy with the use of a "lightwire".

<bold>Purpose: </bold>To determine the accuracy and reproducibility of luminal dimension measurements of a newly developed method of quantitative angioscopy.<bold>Methods: </bold>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.<bold>Results: </bold>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%.<bold>Conclusion: </bold>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. [ABSTRACT FROM AUTHOR]