25 Peripheral Nerve Blocks Flashcards
Qual o artefato abaixo e por que ocorre?
Bayonet artifact is observed during popliteal block of the sciatic nerve.
In this sonogram, the block needle appears to bend as it approaches the sciatic nerve in the popliteal fossa (long arrow). The slower speed of sound in the overlying adipose tissue, compared with the adjacent muscle (short arrow), produces this artifact.
Qual o artefato abaixo e por que ocorre?
Reverberation artifact is observed during femoral nerve block.
Sound waves reverberate back and forth between the walls of the needle and then return later to the transducer. Because the sound waves return at a later time, they are displayed deep within the field of imaging.
No reverberation artifact is observed from the needle tip because the bevel opening does not have opposing walls.
Qual o artefato abaixo e por que ocorre?
Comet-tail artifact is observed during the scanning of the upper airway (arrows).
Small collections of water near the air interface, which also are seen during scanning of the pleura, generate this arti- fact.
Qual o artefato abaixo e por que ocorre?
Posterior acoustic enhancement artifact is observed dur- ing femoral nerve block.
The echoes deep to the femoral artery are enhanced (white arrow) and may be incorrectly identified as the femo- ral nerve (yellow arrow).
Qual o artefato abaixo e por que ocorre?
Acoustic shadowing occurs during regional blocks.
(A) During block of the axillary nerve in the proximal arm, the cortical surface of the humerus reflects and absorbs sound waves, thereby producing acoustic shadowing deep to the bone surface.
(B) During femoral nerve block, air inadvertently injected into the field layers pro- duces strong reflection and acoustic shadowing (arrow).
With experience, operators learn to rock and tilt the transducer naturally to fill in the received echoes from peripheral nerves. ___1___ and ___2___ the transducer achieves needle tip localization after optimizing peripheral nerve echoes by tilting.
- Sliding
- Rotating
O que é Anisotropia?
Anisotropy is the change in echogenicity with inclination of the transducer. In general, when objects are obliquely imaged, they appear less echogenic.
This rela- tionship is most pronounced for tendons but also occurs for muscle and nerves.
Although the term anisotropy was first used to describe changes in received echoes when rocking the transducer with structures viewed in long axis, it has also been used for short-axis views when tilting the transducer. With experience, operators learn to rock and tilt the transducer naturally to fill in the received echoes from peripheral nerves. Sliding and rotating the transducer achieves needle tip localization after optimizing peripheral nerve echoes by tilting.
Qual a diferenca de Color Doppler e Power Doppler
