Image-directed Doppler Ultrasonography Research Articles

Relationship between portal vein blood flow measured by image-directed doppler ultrasonography and hepatic blood flow measured by sorbitol clearance

Relationship between portal vein blood flow measured by image-directed doppler ultrasonography and hepatic blood flow measured by sorbitol clearance

Relationship between liver vein blood flow measured by image-directed doppler ultrasonography and hepatic blood flow measured by sorbitol clearance

Relationship between liver vein blood flow measured by image-directed doppler ultrasonography and hepatic blood flow measured by sorbitol clearance

Ultrasound evaluation of the penis for assessment of impotence

Image directed Doppler ultrasonography of the cavernous arteries provides functional, quantifiable assessment of penile arterial flow during a pharmacological erection. In this respect, this modality is superior to arteriography as a means of evaluating arteriogenic impotence. Peak flow velocity, arterial dilatation, and vessel pulsation are the most reliable ultrasonic indicators of arterial health. Aberrant arterial anatomy should be noted as this may contribute significantly to total penile blood flow. A thorough understanding of erectile physiology and anatomy is necessary to properly perform and interpret Doppler ultrasound results.

Image-directed Doppler ultrasonography: a novel technique for the diagnosis of colorectal liver metastases.

Image-directed Doppler ultrasonography has been used to measure changes in hepatic arterial and portal venous blood flows in 22 controls and 88 patients with colorectal cancer. Doppler Perfusion Index, (DPI, ratio of hepatic arterial to total liver blood flow) and Doppler Flow Ratio (DFR, ratio of hepatic arterial to portal venous blood flow) of controls and patients with overt liver metastases were clearly separated (p < 0.0001). There was a significant reduction in the Hepatic Arterial Resistive Index (HARI) of patients with overt liver metastases (p < 0.0001). Percentage Hepatic Replacement (PHR) by metastases, measured using a computed tomography scanner, did not correlate with DFR or DPI. The results suggest that the measurement of hepatic perfusion changes using image-directed Doppler ultrasonography may be of value in the detection of small liver metastases.

Liver hemodynamic flow balance by image-directed Doppler ultrasound evaluation in normal subjects.

Image-directed Doppler ultrasonography of main hepatic vessels (hepatic artery, portal vein, hepatic veins, and inferior vena cava (IVC)] was performed in 22 healthy volunteers, 20 years to 65 years of age. For each vessel an estimate was made of the diameter, velocity time interval (VTI), volume blood flow in relation to heart rate (stroke volume in L/min/beat), and body size (blood flow index in L/min/m2 body surface area). Moreover, a hemodynamic hepatic balance to define a range of values in normal population was described. The summation of flow of hepatic veins and IVC flow, just over renal veins, (= IVC subhepatic flow) was significantly correlated with the IVC flow rate before entrance into the atrium (R2 = 0.90). Hepatic artery flux plus portal vein flux plus subhepatic vein flux was also related to IVC flux before right atrium entrance (R2 = 0.92). This study confirms the utility and efficiency of Doppler ultrasonography in understanding liver flow hemodynamic balance.

The Response of the Portal Vein to an Oral Glucose Load

Changes of total blood flow, velocities, and cross-sectional area in the portal vein before and after oral glucose administration were studied using image-directed Doppler ultrasonography. Portal vein cross-sectional area, flow velocity, and total blood flow increased significantly compared with baseline studies. Relative increase in these values compared with baseline studies (95% confidence intervals) are presented, and future applications of this method are discussed.