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Thứ Tư, 8 tháng 7, 2020

US SWE ở trẻ em

In fact, for pSWE and 2D-SWE experience in B-mode US is mandatory. Data acquisition should be undertaken by specialists. Operators experienced both in ultrasonography and elastography are needed to obtain reliable liver stiffness measurements in children, considering the different anatomy, especially in babies (liver situated lower in the abdomen), and the fact that cooperation from a small child is sometimes difficult. The location for measurements can be more difficult to establish in children and here the operator’s experience can play a role.

Neonatal brainSome early reports on the use of transcranial SWE of the periventricular brain parenchyma, in preterm infants and infants with hydrocephalus, suggest that SWE is possible and technically feasible [101,102] (fg 5, fg 6).
Albayrak et al showed that differences between brain stiffness values in preterm and term neonates can be demonstrated by using 2D-SWE. Brain stiffness measured from both the thalamus and periventricular white matter were found to be signifcantly lower in preterm neonates compared with term neonates (cut-off values for determining prematurity less than 8.28 kPa for mean
thalamus stiffness and less than 6.59 kPa for periventricular white matter stiffness). The authors suggested that the results might be reference points for evaluating neonatal brain stiffness in research on patients with various illnesses. 2D-SWE also seems to have the ability to depict increased intracranial pressure (ICP) in infants, with a positive linear correlation between SWE values and ICP
[102]. Infants with ICP seem to have increased 2D-SWE values (mean 24.2±5.1 kPa) compared to healthy infants (mean 14.1±6.6 kPa). However, larger prospective studies are still not available. If these preliminary observations of the benefts of transcranial SWE of the neonatal brain will be confrmed by further studies, SWE might be a useful method for additional diagnostic imaging and
monitoring in premature infants and children with proven or suspected increased ICP. When performing SWE of the neonatal brain, potential risks and harms of applying high energy levels by US to the neonatal brain should be considered. Recently, an experimental study on mice dealing with the potential biological effects associated with 2D-SWE on the neonatal brain was published [103].
The results indicated that 2D-SWE does not cause detectable histologic changes in the brain of neonatal mice, nor does it have long-term effects on the learning and memory abilities. However, some temporary effects were observed when the scanning lasted for more than 30 min. Thus, it is recommended to pay attention to the scanning duration when assessing neonatal brains with 2D-     SWE elastography.
The examiner should acquire appropriate knowledge and training in US elastography [104,105]. The operator Fig 5. SWE of the neonatal brain in a healthy newborn (14 days old). Sagittal view of the periventricular region in a healthy newborn. B-mode shows no abnormalities 
(a). 2D-SWE shows a mean periventricular tissue stiffness of 13.5 kPa and a maximum value of 14.8 kPa 
(b). must distinguish a good B mode US image from suboptimal images.