Resumo A ultrassonografia com contraste de microbolhas é um método ainda pouco utilizado no Brasil, mas que tem grandes vantagens, ainda mais na faixa pediátrica, como ausência de radiação e dispensa de sedação/anestesia. O contraste de microbolhas tem se mostrado bastante seguro e com raríssimas reações adversas graves. Apresentaremos nesta revisão a técnica para o uso desse contraste na ultrassonografia, bem como as principais aplicações na faixa pediátrica, como avaliação das lesões hepáticas focais, do trauma abdominal, do enxerto hepático e renal nos transplantes, das alças intestinais e da pesquisa de refluxo vesicoureteral. É importante que radiologistas que exerçam funções em centros pediátricos conheçam essa ferramenta promissora.

Abstract Although contrast-enhanced ultrasound has been shown to provide considerable benefits, particularly in pediatric patients, it is still used relatively rarely in Brazil. It has proven to be a safe technique, and adverse effects are rare. In this review, we address the technique and main applications of contrast-enhanced ultrasound in the pediatric population, including the evaluation of focal liver lesions, abdominal trauma, kidney grafts, liver grafts, bowel loops, and vesicoureteral reflux. It is important for pediatric radiologists to be acquainted with this promising tool, understanding its applications and limitations.

Disturbances involving abnormalities in tooth eruption are named ectopia. Transmigration is the name assigned to ectopia in the presence of teeth in areas distant from the alveolar process. Initial angulation of the tooth bud of the second premolar and premature loss of permanent mandibular 1st molars can influence the distal migration of the second premolar. Some studies have observed that ectopic teeth can be found in a variety of places around the oral cavity and also in other areas of the human body. There are records of teeth in the maxillary sinus, mandibular condyle, coronoid process, mandibular angle, orbit, palate, mentum and also the skin. The prevalence of tooth abnormalities is higher in children with cleft lip and palate compared to children without clefts. This paper presents a case report of migration of the mandibular left second premolar in a patient attending the Hospital for Rehabilitation of Craniofacial Anomalies of the University of São Paulo (HRAC/USP), Brazil. Migration of the mandibular left 2nd premolar was confirmed by 8 panoramic and 1 periapical radiographs obtained during patient's treatment between 1978 and 2002, which were available in the files of the Department of Dental Radiology of HRAC/USP. It can be assumed that distal migration of the mandibular left 2nd premolar is not associated with presence of cleft lip and palate; observation of these two events in a same patient is rare, since no similar reported cases were found in the literature.