[Ultrasonographic diagnosis of athero- and arterio-sclerosis]

Modalities to depict atherosclerotic lesion, have recently been rich in approaches, such as angiography, computed tomography, ultrasonography, radionuclide imaging and magnetic resonance imaging. Although the angiography is still one of the gold standards for diagnosing athero- and arteriosclerotic changes, recent developments in interventional catheterization and medical treatments necessitate the detailed characterization of the vascular wall. High-frequency ultrasonography now expands the observation toward the structure and composition of the vascular wall which can not be obtained in angiography. The higher the frequency of ultrasound is, the better the resolution of the echo imaging improves. However, the adequate depth for echo observation from the probe becomes narrower with the increase of the probe frequency. Accordingly, we have to choose an adequate approach for the vessel of interest. For example, transesophageal echocardiography is useful to evaluate the atherosclerotic changes of the descending aorta. Peripheral ultrasonography is useful for the superficial arteries, including carotid arteries, femoral arteries and branchial arteries. The advantages of the peripheral body surface approach are non-invasiveness and repeatability. Intravascular ultrasonography requires invasive technique, but it provides novel information regarding the presence and the extent of atherosclerosis and its characterization such as calcification. Intravascular ultrasonography is a necessary modality for evaluating the effect of the directional coronary atherectomy.