30. Using Ultrasound to Aid Equivocal Paediatric X-ray Interpretation
Using Ultrasound to Aid Equivocal Paediatric X-ray Interpretation, Alice Ashworth, Helena Ramsden, Jan Soo, Kate Kingston, York and Scarborough Hospitals NHS Trust NHS
Introduction:
Interpretation of paediatric joint radiographs is challenging. Anatomical development is complex, changes with age and is complicated by developmental variation. Epiphyses and apophyses are cartilaginous at birth with progressive, often non-uniform or fragmented ossification causing difficulty in interpretation following trauma, especially by inexperienced clinicians. Specialist paediatric MSK Ultrasound is a potential adjunct in these situations.
Findings:
We present cases where Ultrasound aided diagnosis and guided imaging or clinical management in children where radiographs appeared normal or equivocal, predominantly following trauma but also those limping or not using their arm. Several involved the elbow, a joint readily open to misinterpretation with complex anatomical development involving progressive ossification of epiphyses and apophyses according to the mnemonic CRITOL. X-rays were difficult to interpret initially or showed unexpected changes on follow up when Ultrasound helped problem-solve. We illustrate normal variants, occult fractures and displaced cartilaginous structures including a neonate with complete separation of the distal humeral epiphysis invisible on X-ray and associated with NAI. Acute and chronic apophyseal traction injuries and unexpected sites of ossification during follow-up where ultrasound revealed original injuries were more complex than initially believed. Where postulated intra-articular bodies were normal ossification centres viewed on oblique projections. We describe cases where we ascertained a presumed widened, subluxed ACJ was normal and small ossific fragments at the olecranon and Achilles insertion which lay within cartilage representing tiny secondary ossification centres rather than avulsed fragments from ligamentous injury.
Conclusion:
Ultrasound is a useful adjunct in interpretation of equivocal paediatric joint x-rays, quickly performed in the acute setting to confirm or refute potential injuries. Visualisation of cartilaginous structures is particularly helpful to assess the presence, normal position and alignment of non-ossified epiphyses and apophyses not seen on X-ray without the delays or general anaesthetic often required for MRI. Unexpected findings on follow up x-rays can also be interrogated. Providing this service requires specialist understanding of normal and pathological appearances of paediatric joints on all imaging modalities in combination with senior clinical discussion when the presentation is unclear or unusual.