The many faces of sickle cell disease in children: complications in the appendicular skeleton.

Sickle cell disease (SCD) is a hereditary red cell disorder with clinical manifestations secondary to sickling or crescent-shaped distortion of the red blood cells. Musculoskeletal complications of SCD are often the main causes for acute and chronic morbidities in children with manifestations including osteomyelitis, osteoporosis and osteonecrosis. This article aims to familiarise the paediatric radiologist with appendicular skeletal complications of SCD in the paediatric population and their imaging appearance.

Spectrum of anatomical variants, normal findings and pathology in and around the paediatric sternum.

Abnormalities of the sternum and adjacent structures are an uncommon presentation in the paediatric population and can have a variety of benign and malignant causes, including normal and developmental variants of the chest wall. Although there is overlap with adults, many sternal abnormalities are unique to the paediatric population. Following clinical examination, radiography is usually the first type of imaging used; however, it is limited and often ultrasound and cross-sectional imaging are needed for further assessment. An understanding of the normal anatomy is important; however, this can be challenging due to the varied appearances of age-related changes of the sternum. The purpose of this article is to familiarize the general paediatric radiologist with the expected anatomy and imaging findings of the developing sternum, anatomical variants and pathology of the sternum and adjacent structures encountered in this group of patients.

Complicated Growth Plate Fracture: Torn Metaphyseal Periosteum with Physeal Interposition.

Teaching point: Displacement of torn periosteum into the growth plate is an uncommon pediatric entity following trauma - which can be seen on an MRI as low signal intensity physeal interposition on all pulse sequences, and requires open surgical reduction, as it may lead to growth plate bridging and subsequent extremity length discrepancy.

Imaging Pitfall in the Pediatric Knee: Irregular Epiphyseal Ossification at the Femoral Condyle.

Teaching point: Age-related variability in endochondral ossification of the femoral condyles in children is a normal variant of skeletal maturation and should not be misdiagnosed as osteochondritis dissecans or any other epiphyseal abnormality.

Medical and surgical devices in the emergency and trauma patient: what the radiologist should know, and how they can add value.

A variety of different external and internal medical devices are used in the acute setting to maintain life support and manage severely injured and unstable trauma or emergency patients. These devices are inserted into the acutely ill patient with the specific purpose of improving outcome, but misplacement can cause additional morbidity and mortality. Consequently, meaningful interpretation of the position of devices can affect acute management. Some devices such as nasopharyngeal, nasogastric and endotracheal tubes and chest and surgical drains are well known to most clinicians, however, little formal training exists for radiologists in composing their report on the imaging of these devices. The novice radiologist often relies on tips and phrases handed down in an aural tradition or resorts to phrases such as: "position as shown". Furthermore, radiologists with limited experience in trauma might not be familiar with the radiological appearance of other more specific devices. This review will focus on the most common medical devices used in acute trauma patients, indications, radiological appearance and their correct and suboptimal positioning.

Popeye sign of the semimembranosus.

A 23-year-old amateur football player presented 9 months after acute onset of severe pain and a lump in the posterior right knee whilst lifting a heavy box. He had been unable to return to playing football or climbing the stairs. Clinically, a Baker's cyst was suspected. MRI scan, the imaging modality of choice, was essentially normal. A subsequent ultrasound (US) scan demonstrated abnormal dynamic bunching of the muscle fibres at the distal semimembranosus myotendinous junction on resisted isometric contraction, most likely due to a previous tear isolated to the distal myotendinous junction. The proximal biceps femoris tendon is the most commonly injured part of the hamstring. Distal semimembranosus tears are far less common. Semimembranosus tendinopathy is an uncommon cause of chronic knee pain that is probably underdiagnosed and inadequately treated. In this case, the distal semimembranosus injury was occult on MRI because the features were only apparent with dynamic imaging, something that is not routinely part of musculoskeletal MRI protocols, whereas real-time imaging is easily performed with US. MRI is thought to be more sensitive than US for follow-up imaging of healing hamstring injuries; however, this case highlights the usefulness of dynamic imaging of muscle injuries with US. We propose that the abnormal dynamic muscle bulge on the US image would be aptly described as a "Popeye sign," which, to our knowledge, has not previously been reported in any other anatomical location than the long head of the biceps brachii in the published literature.

Surgical considerations when reporting MRI studies of soft tissue sarcoma of the limbs.

Soft tissue sarcomas (STS) are rare tumours that require prompt diagnosis and treatment at a specialist centre. Magnetic resonance imaging (MRI) has become the modality of choice for identification, characterisation, biopsy planning and staging of soft tissue masses. MRI enables both the operating surgeon and patient to be optimally prepared prior to surgery for the likelihood of margin-negative resection and to anticipate possible sacrifice of adjacent structures and consequent loss of function. The aim of this review is to aid the radiologist in performing and reporting MRI studies of soft tissue sarcomas, with particular reference to the requirements of the surgical oncologist.

Ocular ultrasonography focused on the posterior eye segment: what radiologists should know.

UNLABELLED: Ocular B-mode ultrasonography (US) is an important adjuvant for the clinical assessment of a variety of ocular diseases. When ophthalmoscopy is not possible, mainly due to opacification of the transparent media (e.g., mature cataract or vitreous haemorrhage), US can guide the ophthalmologist in diagnosing disease and choosing treatment. The superficial location and cystic structure of the eye make US ideal for imaging of the eye. Moreover, dynamic study helps distinguish between various conditions that would otherwise be difficult to differentiate in some clinical setting, such as vitreous, retinal, and choroidal detachment. US is also good technique for detecting other pathologic conditions such as lens dislocation, vitreous haemorrhage, asteroid hyalosis, optic disc drusen, and tumors (e.g., choroidal melanoma, metastases, hemangioma). An understanding of the basic anatomy of the eye, the US technique, and common entities that affect the ocular globe will allow radiologists to offer this valuable imaging modality to patients and referring clinicians. This article focuses on the US anatomy and pathologic conditions that affect the posterior ocular segment. TEACHING POINTS: • US is specially indicated when ocular fundus cannot be assessed on ophthalmoscopy. • Multipurpose equipment with high-frequency transducers is optimal for imaging the eye. • Ultrasound can reliably depict ocular anatomy and pathology as detachments and tumours. • Dynamic examination is vital for distinguishing certain pathologic conditions as detachments.