TVP - EDU00447 Como Fazer: Detecção de TVP com Ultrassom SonoSite

Summary

This module, led by Dr. Phil Pereira, focuses on the focused ultrasound examination for detecting deep venous thrombosis (DVT) in the leg. The first part covers the normal anatomy of the leg veins and the techniques for performing a compression ultrasound on the femoral and popliteal veins. The focused DVT exam is highlighted for its efficiency and excellent sensitivity in detecting proximal DVTs, emphasizing the femoral and popliteal regions while excluding smaller calf veins. The module prepares users to identify normal findings, such as vein compression, and sets the stage for part two, which will cover positive DVT diagnoses.

Takeaways

• 😀 The focused ultrasound evaluation of the leg for DVT concentrates on the femoral and popliteal regions to maintain high sensitivity while being time-efficient.
• 😀 The focused DVT exam skips the calf veins, as most radiology-performed DVT exams do the same and focus only on the femoral and popliteal regions.
• 😀 Understanding the anatomy of the lower extremity veins is essential, especially the common femoral vein, deep and superficial femoral veins, and the popliteal vein.
• 😀 The femoral vein is located medially to the common femoral artery and bifurcates into the deep and superficial femoral veins.
• 😀 The superficial femoral vein continues down the leg to become the popliteal vein, which then branches into three calf veins: anterior tibial, posterior tibial, and peroneal.
• 😀 In the focused DVT exam, compression of the femoral and popliteal veins with the probe helps identify DVT, as a clot prevents complete vein collapse.
• 😀 The common femoral vein can be easily identified with the high-frequency linear array probe, placed just below the inguinal ligament, where the artery is located laterally.
• 😀 Color flow Doppler can help differentiate arteries from veins by showing pulsatile flow in arteries and phasic flow in veins, although B-mode sonography is sufficient for diagnosis.
• 😀 A normal compression exam results in complete collapse of the vein walls, while a thrombus in the vein prevents this compression.
• 😀 During the popliteal vein examination, the probe is placed at the posterior aspect of the knee, where the popliteal vein is more posterior to the popliteal artery.

Q & A

What is the focus of the ultrasound examination described in this module?

The module focuses on the ultrasound evaluation of the leg for deep venous thrombosis (DVT), specifically the focused or limited DVT exam, which targets the femoral and popliteal veins for increased speed and accuracy.

What are the key regions examined in the focused DVT ultrasound examination?

The focused DVT ultrasound examination concentrates on two specific areas of the leg: the femoral region and the popliteal region.

Why is the focused DVT examination preferred over the traditional full DVT examination?

The focused DVT examination allows for increased speed, while maintaining excellent sensitivity in detecting proximal DVTs. It is also more efficient as it skips the examination of the calf veins, which are harder to visualize.

What is the importance of the saphenous vein in DVT examination?

The saphenous vein is crucial because it is the only superficial vein in the body that can propagate clot formation directly into the common femoral vein, potentially leading to further complications like clots reaching the inferior vena cava (IVC) and heart.

How is the normal compression exam performed on the femoral vein?

To perform the normal compression exam on the femoral vein, the high-frequency linear probe is placed over the common femoral vein and artery, just below the inguinal ligament. Sequential compression is applied from the top of the vein down to the bifurcation into the superficial and deep femoral veins. The vein should completely collapse with probe pressure in a normal exam.

How does the presence of a thrombus affect the compression exam of the femoral vein?

If a thrombus is present, the femoral vein will not completely collapse when pressure is applied with the probe. This failure to collapse indicates the presence of a clot.

What distinguishes the common femoral artery from the common femoral vein in ultrasound imaging?

In ultrasound imaging, the common femoral artery is seen laterally (to the left) of the common femoral vein, and it exhibits pulsatile flow. The vein, located medially (to the right), has a phasic flow pattern, and its walls collapse with compression.

What is the proper orientation for the probe during the popliteal vein examination?

During the popliteal vein examination, the probe should be placed high within the popliteal fossa with the marker dot oriented laterally. The probe should compress the vein sequentially from high in the fossa down to the trifurcation of the vessel.

What are the key veins and arteries visualized during the focused DVT exam?

The key veins visualized are the common femoral vein, deep femoral vein, superficial femoral vein, popliteal vein, and the calf veins (anterior tibial, posterior tibial, and peroneal veins). The associated arteries include the common femoral artery, deep femoral artery, superficial femoral artery, and the popliteal artery.

What is the role of color flow Doppler in DVT ultrasound examinations?

Color flow Doppler is used to differentiate between arteries and veins by visualizing pulsatile flow in arteries and phasic flow in veins. However, Doppler is not essential for the basic diagnosis of DVT; B-mode sonography provides most of the necessary information.