Use of greyscale and Doppler ultrasound in initial evaluation and follow-up of neurovascular malformations in children.

Pediatric intracranial arteriovenous shunts are rare vascular malformations that can be diagnosed prenatally or postnatally, as an incidental finding or due to complications. We propose a review of cerebral vascular malformations in newborns and infants with special emphasis on neurosonography and Doppler ultrasound as the first diagnostic method. Sonography can thus contribute in the planning of further studies that are always necessary, and in post-therapy follow-up.

Hallazgos ecográficos de nódulos tiroideos: un reto diagnóstico en pediatría / Ultrasound findings of thyroid nodules: a diagnostic challenge in pediatrics

Resumen Los nódulos tiroideos son poco frecuentes en pediatría, pero uno de cada cuatro de ellos es maligno. La ecografía es el método de elección en la detección de estos nódulos porque brinda información que permite, en muchos casos, determinar la probabilidad de malignidad. Las características a definir en un nódulo tiroideo son: composición, márgenes, ecogenicidad, calcificaciones, vascularización, dureza y la presencia de ganglios linfáticos cervicales patológicos. La composición comprende la apariencia quística, sólida o mixta (contiene al subtipo espongiforme). Los márgenes se describen como lisos, irregulares, mal definidos o lobulados. La ecogenicidad se define como hiperecoicos, hipoecoicos o isoecoicos en relación con el parénquima tiroideo adyacente. En los casos de nódulos heterogéneos se describe el patrón predominante. Dentro de las calcificaciones se describen las microcalcificaciones y macrocalcificaciones. La vascularización se clasifica como normal, aumentada central o periférica, y mixta al examen Doppler color. La elastografía mide la rigidez del nódulo evaluado en comparación con el tejido tiroideo adyacente. Por último, se debe evaluar la cadena ganglionar cervical en búsqueda de alteración de su ecoestructura. Es primordial el reconocimiento de las características de benignidad y malignidad de estas lesiones, ya que permitirá guiar al especialista para la toma de decisiones.

Abstract Thyroid nodules are rare in pediatrics, but up to one in four of them is malignant. Ultrasound is the method of choice in the detection of thyroid nodules because it provides information that allows to determine the probability of malignancy in many patients. The characteristics to be defined in a thyroid nodule are: composition, margins, echogenicity, calcifications, vascularization, stiffness and the presence of pathological cervical lymph nodes. Composition includes cystic, solid or mixed appearance (contains the spongiform subtype). Margins are described as smooth, irregular, ill-defined or lobulated. Echogenicity is defined as hyper-, hypo- or isoechoic to the adjacent thyroid parenchyma. Calcifications are described as microcalcifications and macrocalcifications. Vascularization is classified as normal, increased central or peripheral, and mixed on color Doppler. Elastography measures the stiffness of the evaluated nodule compared to the adjacent thyroid tissue. Finally, cervical lymph nodes should be evaluated for alterations in its echostructure. It is essential to recognize the benign and malignant characteristics of this type of lesions, as this will guide the specialist in making decisions.

Ultrasound attenuation imaging: a reproducible alternative for the noninvasive quantitative assessment of hepatic steatosis in children.

BACKGROUND: Pediatric hepatic steatosis is a global public health concern, as an increasing number of children are affected by this condition. Liver biopsy is the gold standard diagnostic method; however, this procedure is invasive. Magnetic resonance imaging (MRI)-derived proton density fat fraction has been accepted as an alternative to biopsy. However, this method is limited by cost and availability. Ultrasound (US) attenuation imaging is an upcoming tool for noninvasive quantitative assessment of hepatic steatosis in children. A limited number of publications have focused on US attenuation imaging and the stages of hepatic steatosis in children. OBJECTIVE: To analyze the usefulness of ultrasound attenuation imaging for the diagnosis and quantification of hepatic steatosis in children. MATERIAL AND METHODS: Between July and November 2021, 174 patients were included and divided into two groups: group 1, patients with risk factors for steatosis (n = 147), and group 2, patients without risk factors for steatosis (n = 27). In all cases, age, sex, weight, body mass index (BMI), and BMI percentile were determined. B-mode US (two observers) and US attenuation imaging with attenuation coefficient acquisition (two independent sessions, two different observers) were performed in both groups. Steatosis was classified into four grades (0: absent, 1: mild, 2: moderate and 3: severe) using B-mode US. Attenuation coefficient acquisition was correlated with steatosis score according to Spearman's correlation. Attenuation coefficient acquisition measurements' interobserver agreement was assessed using intraclass correlation coefficients (ICC). RESULTS: All attenuation coefficient acquisition measurements were satisfactory without technical failures. The median values for group 1 for the first session were 0.64 (0.57-0.69) dB/cm/MHz and 0.64 (0.60-0.70) dB/cm/MHz for the second session. The median values for group 2 for the first session were 0.54 (0.51-0.56) dB/cm/MHz and 0.54 (0.51-0.56) dB/cm/MHz for the second. The average attenuation coefficient acquisition was 0.65 (0.59-0.69) dB/cm/MHz for group 1 and 0.54 (0.52-0.56) dB/cm/MHz for group 2. There was excellent interobserver agreement at 0.94 (95% CI 0.92-0.96). There was substantial agreement between both observers (κ = 0.77, with a P < 0.001). There was a positive correlation between ultrasound attenuation imaging and B-mode scores for both observers (r = 0.87, P < 0.001 for observer 1; r = 0.86, P < 0.001 for observer 2). Attenuation coefficient acquisition median values were significantly different for each steatosis grade (P < 0.001). In the assessment of steatosis by B-mode US, the agreement between the two observers was moderate (κ = 0.49 and κ = 0.55, respectively, with a P < 0.001 in both cases). CONCLUSION: US attenuation imaging is a promising tool for the diagnosis and follow-up of pediatric steatosis, which provides a more repeatable form of classification, especially at low levels of steatosis detectable in B-mode US.

Bidimensional shear-wave elastography for assessing liver fibrosis in children: a proposal of reference values that correlate with the histopathological Knodell-Ishak score.

BACKGROUND: A limited number of publications correlate bidimensional shear-wave elastography (2-D SWE) and stages of liver fibrosis in children. OBJECTIVE: To correlate liver elastography values using 2-D SWE and liver biopsy classified by Knodell-Ishak score to evaluate fibrosis in pediatric patients with liver disease, and to propose values of 2-D SWE (kPa) correlating with Knodell-Ishak score, which have not been defined in the literature. MATERIALS AND METHODS: We conducted a prospective cross-sectional observational study on the performance of diagnostic tests. Between June 2016 and June 2018, elastography was performed in 213 children and young adults who had undergone liver biopsy. B mode, Doppler and 2-D SWE were performed using an Aixplorer (SuperSonic Imagine, Aix-en-Provence, France). Histology samples were classified using the Knodell-Ishak score. We evaluated performance by assessing sensitivity, specificity, positive predictive value and negative predictive value. To determine cut-off points for the continuous variables, we used receiver operating characteristic (ROC) curves. All the cutoff values we established apply only to the SuperSonic Aixplorer system. RESULTS: Measurement with 2-D SWE was successful, with a good correlation with fibrosis stage. The area under the curve (AUC) to differentiate between early (Stages 1-2) and moderate (Stages 3-4) fibrosis was 0.91 (95% confidence interval [CI]: 0.87-0.96), with a sensitivity of 92% and specificity of 86%, with a cutoff value 12 kPa (2 m/s). The AUC of severe fibrosis (early stages of cirrhosis; Stage 5) was 0.95 (95% CI: 0.92-0.97), with a sensitivity of 94% and specificity of 90%, with a cutoff value 18.5 kPa (2.48 m/s). In two patients with hematopoietic stem cell transplantation and suspicion of graft versus host disease we found high 2-D SWE values in correlation with the fibrosis stages (Stage 0 with a median of 13 kPa [2.08 m/s] with hemosiderosis Grade 2 in one child and Stage 2 with a median of 46 kPa [3.91 m/s] and hemosiderosis Grade 4 in the other). CONCLUSION: Our study shows the usefulness and accuracy of 2-D SWE for detecting liver fibrosis in pediatric patients. We propose reference values for Knodell-Ishak Stages 1 and 5. We found hemosiderosis as a possible confounding factor that hasn't been described with 2-D SWE.