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Intravascular angioscopy has been hampered by its limitation in quantifying obtained images. To circumvent this problem, a lightwire was used, which projects a ring of light onto the endoluminal wall in front of the angioscope. This investigation was designed to quantify luminal dimensions of casts from stenotic human coronary arteries and to investigate the feasibility of performing volume reconstruction. Angioscopic video recordings were made during simultaneous motorized pullback (2 mm/s) of an angioscopic catheter and light-emitting fiber through 4 epoxy casts from human coronary arteries. Quantification of the images was performed using a computerized cross-sectional area measurement system. The coronary casts were divided into cross-sectional segments of 4 to 10 mm in thickness, with the true volume of each segment determined by means of a microdispenser. Because of vessel curvature and luminal narrowing, complete visualization of the ring of light at all 1-mm-distant locations was only possible in 19 of 40 segments. For these 19 segments, linear regression analysis showed a good correlation between measured and true segmental volume (r = 0.97, y = 0.88x + 6.58 [mm.sup.3], standard error of estimate = 3.48 [mm.sup.3]). The relative error in the measured segmental volumes was 3.9 7.1% (mean [+ or -] SD). These initial results of endoluminal volume reconstruction demonstrate the feasibility of this technique in vitro with high accuracy and low variability, but further technical improvements are necessary to increase the success rate, especially in the quantitative assessment of vessels with complex morphology. (Am J Cardiol 1994;74-764-768)

To develop quantitative analysis of regional left ventricular waLl motion in the absence of a gold standard, on objective statistical measure to compare models of wail motion is described. This measure can be derived from wail motion analysis of subgroups of patients with different patterns of wall motion. A priori knowledge of the exact localization of wail motion abnormalities is not needed. Two-dimensinal echocardiograms were analyzed from 79 patients with myocardial infarction. The following 4 models were compared: Model I was based on the descent of the base toward the stable apex during systole. Models II and III measured area reduction with fixes and floating-reference systems, respectively. Model IV was the centerline model. Classfication by the electrocardiogram of the myocardial infarction as anterior (n= 37), postedof (n= 17) and Inferior (n- 25) provided the a priori probability for classification of myocardial Infarction. The a posteriori probability for classification of myocardial infarction was derived from the detection of wall motion abnormalities by echocardiographic analysis. The mean difference between a posterioi and a priori probability is a measure for the diagnotic value of the model, and was measured for 200 regions/patient. Use of the described measure revealed model I to be the most informative model and model III the least informative. Thus, the described statistical measure contributes to the development of regional wail motion analysis. (Am J Cardiol 1993;71:1262-1269)

In vitro and animal experiments have shown that the severity af coronary stenoses can be assessed using the continuity equation if the maximal blood flow velocity of the stenotic jet is measured. The large diameter and the low range of velocities measurable without frequency aliasing with the conventional intracoronary Doppler catheters precluded the clinical application of this method for hemodynamically significant coronary stenoses in humans. This article reports the results obtained using a 12 MHz steerable angioplasty guidewire in a consecutive series of 52 patients undergoing percutaneous coronary angioplasty (61 coronary stenoses). The ratio between coronary flow velocity in a reference segment and in the stenosis was used to estimate the percent cross-sectional area stenosis. A Doppler recording suitable for quantization was obtained in the stenotic segment in only 10 of 61 arteries (16%). The time-averaged peak velocity increased from 15 [+ or -] 5 to 115 [+ or -] 26 cm/sec from the reference normal segment to the stenosis. Volumetric coronary flow calculated from the product of mean flow velocity and cross-sectional area was similar in the stenosis and in the reference segment (33.2 [+ or -] 14.9 vs 33.5 [+ or -] 17.0 mL/ min, respectively, difference not significant). The percent cross-sectional area stenosis and minimal luminal cross-sectional area derived from the Doppler velocity measurements using the continuity equation and calculated with quantitative angiography were also similar (Doppler, 86.7 [+ or -] 5.1% and 1.00 [+ or -] 0.48 [mm.sup.2]; quantitative angiography, 85.9 [+ or -] 7.9% and 1.02 [+ or -] 0.50 [mm.sup.2]). A significant correlation was observed between Doppler-derived and angiographic measurements (percent cross-sectional area: r = 0.64, p < 0.05; minimal cross-sectional area: r = 0.69, p < 0.05). Although the percent cross-sectional area stenosis and minimal cross-sectional area derived from the Doppler measurements based on the continutty equation were significantly correlated with the corresponding quantitative angiographic measurements, this determination could be achieved in a minority of cases (16%), limiting the practical application of this approach for the assessment of coronary stenosis severity. (Am J Cardiol 1993;71:54D-61D)