Radiography, CT, and MRI of Hip and Lower Limb Disorders in Children and Adolescents.

Infants and children are vulnerable to congenital and developmental hip and lower extremity disorders. These disorders have diverse causes in pediatric patients, and owing to potential related complications that can lead to degenerative disease in adulthood, an accurate diagnosis is essential. A common disease is developmental dysplasia of the hip, which affects nearly 1% of newborns. This condition is best evaluated with US and conventional radiography. Slipped capital femoral epiphysis affects approximately 0.01% of young teenagers and is initially evaluated with radiography. Femoroacetabular impingement is a risk factor for early osteoarthritis and can be assessed with radiography, CT, or MRI. Limb length discrepancy is defined as a greater than 2-cm difference in length between paired bilateral lower extremities. There are several methods of measuring this difference, and the use of an accurate imaging modality is essential for treatment. Developmental bowing is a physiologic condition involving varus angulation of the knee and is best evaluated by using conventional radiography. Blount disease is a progressive pathologic genu varum centered at the tibia; the three subtypes are infantile, juvenile, and adolescent. In- and out-toeing disorders are caused by abnormal tibial and femoral torsion that usually self-corrects during lower limb growth. The ability to recognize these conditions is essential for differentiating those that will resolve spontaneously versus those that will require treatment. The imaging features of congenital and developmental hip and lower extremity disorders are reviewed, with emphasis on diagnosis, radiologic assessment, associated findings, and classification. ©RSNA, 2019.

Importância da ressonância magnética na avaliaçäo das lesöes traumáticas da placa de crescimento epifisária / Magnetic ressonance imaging importance in evaluation of the traumatic lesions of the epiphyseal growth plate

Estudo retrospectivo de nove pacientes que sofreram lesao traumática da placa de crescimento foi realizado através da análise de seus prontuários, com o objetivo de determinar o valor da ressonância magnética no diagnóstico precoce das lesoes pós-traumáticas da placa de crescimento e também na capacidade de identificar o tipo, localizaçao e extensao da lesao, para melhor planejar o tratamento. As ressonâncias magnéticas foram realizadas com séries pesadas em T1, T2 e T2* (gradiente eco), nos planos coronais e sagitais. Em dois casos de lesao traumática aguda sem desvio da placa de crescimento, foi possível sua identificaçao. Nos casos em que havia ponte através da placa de crescimento, foi possível identificar sua localizaçao, sua extensao e ainda diferenciar entre ponte óssea ou fibrosa, com exceçao de um caso. Os resultados mostraram que a RM é um eficiente método na detecçao precoce das alteraçoes pós-traumáticas da placa de crescimento, assim como na determinaçao da localizaçao e extensao dessas, contribuindo muito para o planejamento terapêutico.