News (Page 20)

Intravascular Ultrasound Imaging of Pulmonary Arteries: Limitations of Pulmonary IVUS

Despite the advantages of pulmonary IVUS imaging over other currently available techniques, there are limitations with this method that need to be overcome. First, the proximal pulmonary arteries are large and often beyond the penetration of 12 to 30 MHz ultrasound frequencies: 5 to 20 mm depth penetration depending on the frequency used. Therefore, lower […]

Intravascular Ultrasound Imaging of Pulmonary Arteries: Safety of Pulmonary IVUS

Pulmonary vascular stiffness responses are assessed using both pulmonary artery pulse pressure and intravascular ultrasound-derived pulmonary artery area changes in the cardiac cycle. The pulmonary artery stiffness responses to nitroglycerin in patients with secondary pulmonary hypertension are variable and not predicted by the change in mean pulmonary artery pressure or pulmonary vascular resistance. These data […]

Intravascular Ultrasound Imaging of Pulmonary Arteries: Pulmonary IVUS to Assess Pathophysiology

The focal pulmonary artery stenoses were balloon dilated, resulting in increases in lumen area. The IVUS findings were associated with an improvement in pulmonary artery hemodynamics. Assessment of Response to Drug Therapy: Pulmonary artery IVUS has been used to detect different pulmonary vascular area responses to dobu-tamine and nitroglycerin in patients with chronic heart failure […]

Intravascular Ultrasound Imaging of Pulmonary Arteries: Pulmonary IVUS Guidance in Therapy

Secondary pulmonary hypertension may occur in response to pulmonary parenchymal disease, leftsided heart failure, or mitral valve disease. Intravascular ultrasound has been used to detect abnormalities in vessel wall thickness in pulmonary hypertension secondary to left-sided heart failure, and to determine how this correlates with wall stiffness. Pulmonary IVUS (6F 20 MHz) of vessels from […]

Intravascular Ultrasound Imaging of Pulmonary Arteries: Pulmonary Thromboembolic Disease

Chronic Pulmonary Thromboembolic Disease: Recent clinical studies have also showed the ability of pulmonary IVUS to diagnose chronic pulmonary thromboemboli. Ricou et al used an 8F 20 MHz IVUS catheter to detect abnormalities in the left and right pulmonary arteries of patients with chronic thromboemboli. These abnormalities were described as either marked thickening of the […]

Intravascular Ultrasound Imaging of Pulmonary Arteries: Validation of Pulmonary IVUS Imaging

Using a disposable 6F 20 MHz ultrasound probe in isolated pulmonary artery segments of dogs, it has been shown that IVUS-derived measurements of pulmonary artery area, diameter, and wall thickness correlated very well with anatomic measurements in vitro (Fig 1). In this preliminary study, pulmonary IVUS images in humans were also obtained and provided detailed […]

Intravascular Ultrasound Imaging of Pulmonary Arteries: Pulmonary IVUS Instrumentation

This technique has been used to examine 1.0- to 4.5-mm diameter pulmonary arteries in humans with chronic lung disease. It has also accurately detected acute pulmonary emboli in dogs. It has been used clinically in patients suspected of having chronic pulmonary emboli where the angiogram is not conclusive. In these cases, angio-scopy has been useful […]