Quantification of coronary calcification by intravascular ultrasound.

Background: Previous intravascular ultrasound (IVUS) studies have shown that calcification can be quantified by the determination of the arc on one cross-section. However, because calcium levels change along the length of lesions, it is important to assess the length of calcium using serial cross-sectional images. The correlation between the largest arc and length of each calcium deposit in patients with coronary artery disease (CAD) has not been determined. The present study was performed to determine this correlation.
Methods and Results: Pre-interventional IVUS images of 194 patients with CAD were studied. The largest arc and length of all calcium within the 10-mm-long culprit lesion segment were quantified using serial cross-sectional images. One hundred and ninety-four patients had 277 calcium deposits. In all patients, the length of each calcium exhibited a strong correlation with the largest arc of calcium (R=0.750, p<0.0001).
Conclusions: Our findings revealed the quantitative characteristics of each calcium within the culprit lesion segment. They will be useful in interpreting results of previous and future IVUS studies, which deal only with the arc of calcium, as well as studies using new modalities such as computed tomography that assess calcium mainly along the long axis of the coronary artery.