alcification is a common finding in human coronary arteries, and has usually been interpreted as an indicator of advanced atherosclerosis. 1 In the past few decades, arterial calcification has been considered passive and degenerative. With recent clinical and basic research, however, there is increasing recognition that arterial calcification is an active, regulated process. 2 In particular, following the introduction of electron-beam computed tomography (EBCT), which permits the quantitative assessment of coronary artery calcification, there have been rapidly increasing numbers of clinical studies of coronary calcification. Some studies have shown that EBCT-detected coronary calcification correlates with the degree of plaque burden in the entire coronary tree. 3 More recently, multislice computed tomography (MSCT) has allowed for the detection of not only coronary artery calcification but also coronary artery stenoses and plaques. 4 Coronary calcifications detected by MSCT can be assessed along the long axis of the coronary artery. However, it is difficult to assess the circumference of calcium deposits using cross-sectional images obtained by MSCT.Intravascular ultrasound (IVUS), in contrast, enables the identification of calcium deposits and exact measurements of vessel diameters and areas, including those associated with culprit lesions. A number of IVUS studies have focused on detailed assessment of calcification. However, neither total areas nor volumes of calcium deposits can be accurately determined using current IVUS technology, because calcium deposits produce acoustic shadowing.Previous studies with IVUS have demonstrated that calcification can be quantified as the arc on cross-sections. 5,6 For IVUS, this approach of quantification of vessel calcium is generally accepted and acknowledged as the most reliable method of assessment of plaque calcium along the length of lesions. Another approach is to determine the length of calcium using serial cross-sectional IVUS images. 7,8 However, little is known about the correlation between the largest arc and the length of each calcium deposit within the culprit lesion segment in patients with coronary artery disease. The combination of the largest arc and the length is quite complex in IVUS analysis. The question arises whether calcium deposits with larger arcs have a longer length. The present study was designed to answer this question.
MethodsThe study was approved by the hospital ethics committee, and written informed consent was obtained from all patients before the study.
PatientsPreinterventional IVUS images were obtained from 212 Shoichi Ehara, MD; Yoshiki Kobayashi, MD; Toru Kataoka, MD; Minoru Yoshiyama, MD; Makiko Ueda, MD*; Junichi Yoshikawa, MD** 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 i...