Ultrasound of the inferior vena cava and hepatic veins
Last reviewed: 18.10.2021
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Ultrasound anatomy
The lower hollow vein is located to the right of the spine, passing through the diaphragm, and falls into the right atrium. The main inflows visualized with ultrasound dopplerography are iliac veins, renal veins and three hepatic veins that flow into the lower vena cava immediately below the diaphragm. You can find more than three hepatic veins, when the outflow from the tail of the liver is carried out on a separate vein.
Methods of ultrasound of the inferior vena cava and hepatic veins
Ultrasonic dopplerography of the inferior vena cava system is usually an inferior vena cava in a color regime in two planes along its entire length. When anomalies are detected, the Dopcher spectra are recorded for the purpose of quantitative evaluation.
Normal ultrasound picture of the inferior vena cava and hepatic veins
Blood flow in the inferior vena cava and hepatic veins has a clear dependence on the cardiac cycle. The movement of the valves of the heart valve towards the apex creates a pronounced sucking effect within the atrium, which causes a rapid inflow of blood to the heart. When the right atrium is filled to the beginning of diastole, the venous inflow decreases or even a certain period of reverse blood flow can be determined. At the opening of the atrioventricular valves, blood enters the ventricles, and the venous influx into the atrium can again be performed. By the end of diastole the atrium is contracting. Since there are no valves between the terminal veins and the atrium, this contraction causes a transient outflow from the heart. Closure of the atrioventricular valves at the end of the diastole sometimes leads to the formation of a small notch on the line of the spectrum.
Right ventricular failure can lead to a change in the pattern of spectral waves, while the flow of blood to the heart decreases. Insufficiency of the tricuspid valve leads to the appearance of a pathologic reverse blood flow along the inferior vena cava to the systole. Flat spectra reminiscent of the tape can be recorded in patients suffering from cirrhosis of the liver in a far-advanced stage.
Thrombosis of the inferior vena cava is manifested in B-mode by the inability of vein compression, loss of pulsation and hypoechoic dilatation, which is still somewhat more echogenic than in the echo-negative lumen. In the color mode, the color cavity in the region of the affected segment is determined, which is caused, for example, by an extensive thrombosis of the left common iliac vein. The right common iliac vein gives residual blood flow in the inferior vena cava in the form of a crescent).
Filters in the inferior vena cava can reduce the risk of embolization from the veins of the pelvis and lower extremities, but complications are often observed. Metal filters installed intraluminally can be displaced or thrombosed and become a source of emboli. Ultrasonic Doppler is a method of monitoring and determining the location of the filter.
Narrowing of the lumen of the inferior vena cava can have other causes besides thrombosis, for example, postoperative complications, stenosis, intraluminal tumor growth or external compression by a tumor.
The thrombosis can affect individual small hepatic veins (vein-occlusive disease) or the main venous trunks (Badd-Chiari syndrome), sometimes with the defeat of the inferior vena cava. With thrombosis of individual veins or venous segments, the absence of blood flow in ultrasound Doppler ultrasound can be combined with intersegmentary collateralization and the Doppler spectrum in the form of a band.
Intrahepatic formations, such as angioma, can displace and narrow the hepatic veins, reaching significant dimensions.