Karl Johnson

Imaging of juvenile idiopathic arthritis.

Over the past decade there have been considerable changes in the classification and imaging of juvenile idiopathic arthritis (JIA). Radiology now has a considerable role in the management of JIA, the differential diagnosis, monitoring disease progression and detecting complications. The different imaging modalities available, their role and limitations are discussed in this article and the various disease features that the radiologist should be aware of are described. An approach to the imaging of the child with joint disease and in the monitoring of disease complications are also discussed.

Evaluation of mebrofenin hepatoscintigraphy in neonatal-onset jaundice.

Background. The prognosis of infants with prolonged neonatal jaundice is dependent on early diagnosis because of the need for prompt surgical management of biliary atresia. Objective. To evaluate the usefulness of 99 mTcm-trimethylbromo-iminodiacetic acid (TBIDA, mebrofenin) in the investigation of infantile jaundice. Materials and methods. A retrospective study was undertaken of 58 patients with unexplained prolonged neonatal jaundice. Sixty-eight scans were reviewed. Results. Mebrofenin scintigraphy confirmed the presence of a choledochal cyst in three of the four cases with that diagnosis. There were no false negative results in the nine patients with extrahepatic biliary atresia (EHBA). Three further infants had an incorrect histological diagnosis of EHBA. A gall bladder was identified by US in each case and in one of these, scintigraphy showed gut excretion. In the 16 patients with no gut excretion by 24 h, the final diagnoses were intrahepatic cholestasis (n = 7), Alagilles syndrome (n = 3), neonatal hepatitis (n = 3), alpha-1-antitrypsin deficiency (n = 2) and juvenile xanthogranuloma (n = 1). Seven infants had repeat scintigraphy after the administration of ursodeoxycholic acid (URSO). This changed five non-excretors with hepatitis into excretors. Two infants with hepatitis continued to show non-excretion after URSO, but a gallbladder was identified by US in both. Conclusions. Mebrofenin scintigraphy is accurate in confirming the presence of a choledochal cyst and in refuting the diagnosis of EHBA. While histology and scintigraphy are each 100 % sensitive for the diagnosis of EHBA, neither, individually, is accurate and the investigation of prolonged neonatal jaundice requires a multi-modality imaging strategy.

MRI in the management of scaphoid fractures in skeletally immature patients

Background. The scaphoid is the commonest fractured carpal bone, but excluding a scaphoid fracture with plain radiographs is difficult. Other imaging modalities are being increasingly evaluated in the management of scaphoid injuries. MRI has been shown to be of considerable value in the adult population but there have been limited studies of its use in children.¶Purpose. To evaluate the role of MRI in the acute management of suspected scaphoid injuries in children.¶Methods and materials. Fifty-six children (57 injuries) who had a suspected scaphoid injury underwent MRI within 10 days of their initial trauma. The results of MRI were used to dictate management of the injury.¶Results. In 33 (58 %) of the 57 injuries, MRI was normal and the patient was discharged from care. In 16 cases (28 %), a fractured scaphoid was diagnosed and appropriate treatment started early. Additionally, other fractures around the wrist joint and ganglion cysts were demonstrated on MRI.¶Conclusions. MRI of acute scaphoid injuries in children significantly alters management. Those children with normal scans are discharged earlier. Scaphoid fractures are confirmed earlier and other pathological conditions are also detected.

Childhood idiopathic chondrolysis of the hip: MRI features

BackgroundChildhood idiopathic chondrolysis of the hip (ICH) causes progressive destruction of the articular cartilage of the hip joint with associated bone remodelling. The MRI features of this disease have not previously been described.ObjectiveTo document the MRI features of childhood ICH and determine which features may help distinguish ICH from other causes of hip joint destruction in the paediatric population.Materials and methodsA retrospective review of the MRI examinations of children with clinically diagnosed ICH. All children had undergone synovial biopsy and/or joint aspiration with plain hip radiography to exclude causes of secondary chondrolysis.ResultsTen MRI examinations were performed on six children. Cartilage loss, small hip joint effusions, bone remodelling and significant regional muscle wasting were seen in all children. Cartilage loss was most severe in the central part of the joint. Synovial enhancement was not a constant feature of ICH. Serial imaging in three children showed disease progression.ConclusionsMRI in ICH clearly demonstrates cartilage loss and enables delineation of bone and muscle abnormalities. It is helpful in the differential diagnosis of hip joint disease in children and may provide further information on the progression and aetiology of ICH.

MRI in Juvenile Idiopathic Arthritis and Juvenile Dermatomyositis

The use of MRI in the assessment of the musculoskeletal system in children has important differences from its use in adults. Growth in children has significant impact on the epiphysis and growth plate, which are important structures in the growing child, and there are radiological features that differ from those in adults: disease may alter structures during a period of growth; the pathologies themselves are a distinct group of diseases at variance with adult arthritis and myositis, with a different spectrum of differential diagnoses; and many technical issues are different when imaging a child. These are important considerations in choosing the appropriate imaging. MRI is a powerful and valuable imaging technique in pediatric musculoskeletal pathologies, with considerable potential for future developments to enhance its role in diagnosis, management, and therapeutic intervention for these children.

Not a NICE CT protocol for the acutely head injured child

AIM To assess the impact of the introduction of the Birmingham Childrens Hospital (BCH) head injury computed tomography (CT) guidelines, when compared with the National Institute of Health and Clinical Excellence (NICE) guidelines, on the number of children with head injuries referred from the Emergency Department (ED) undergoing a CT examination of the head. MATERIAL AND METHODS All children attending BCH ED over a 6-month period with any severity of head injury were included in the study. ED case notes were reviewed and data were collected on a specifically designed proforma. Indications for a CT examination according to both NICE and BCH head injury guidelines and whether or not CT examinations were performed were recorded. RESULTS A total of 1428 children attended the BCH ED following a head injury in the 6-month period. The median age was 4 years (range 6 days to 15 years) and 65% were boys. Four percent of children were referred for a CT using BCH guidelines and were appropriately examined. If the NICE guidelines had been strictly adhered to a further 8% of children would have undergone a CT examination of the head. All of these children were discharged without complication. The remaining 88% had no indication for CT examination by either BCH or NICE and appropriately did not undergo CT. CONCLUSIONS Adherence to the NICE head injury guidelines would have resulted in a three-fold increase in the total number of CT examinations of the head. The BCH head injury guidelines are both safe and appropriate in the setting of a large childrens hospital experienced in the management of children with head injuries.

Skeletal injuries associated with sexual abuse

Background: Sexual abuse is often associated with physical abuse, the most common injuries being bruising and other soft-tissue injuries, but fractures occur in 5% of sexually abused children. The fractures described to date have formed part of the spectrum of injuries in these children and have not been specifically related to the abusive act. Objective: To describe concurrent sexual abuse and fractures. Materials and methods: Three children with pelvic or femoral shaft injuries in association with sexual abuse. Results: A 3-year-old girl with extensive soft-tissue injuries to the arms, legs and perineum also sustained fractures of both pubic rami and the sacral side of the right sacro-iliac joint. A 5-month-old girl with an introital tear was shown to have an undisplaced left femoral shaft fracture. A 5-year-old girl presented with an acute abdomen and pneumoperitoneum due to a ruptured rectum following sexual abuse. She had old healed fractures of both pubic rami with disruption of the symphysis pubis. Conclusions: Although the finding of a perineal injury in a young child may be significant enough for the diagnosis of abuse, additional skeletal injuries revealed by radiography will assist in confirmation of that diagnosis and may be more common than hitherto suspected.

Ultrasonographic Phases in Gap Healing Following Ponseti-Type Achilles Tenotomy

BACKGROUND The Ponseti technique is well established in the management of clubfoot deformity, and an Achilles tenotomy is frequently performed to facilitate dorsiflexion of the foot. This report describes the ultrasonographic phases of healing of the tendon gap created by the Achilles tenotomy and how the healing varies, if at all, with patient age. METHODS A prospective ultrasonographic study of gap healing following a Ponseti-type tenotomy in twenty-seven tendons in twenty patients with idiopathic congenital clubfoot was performed. Serial ultrasound examinations (both static and dynamic) were performed at three, six, and twelve weeks after the tenotomy. The casts were removed routinely three weeks after the tenotomy. The end point of healing was defined as the observation of tendon homogeneity across the gap zone on ultrasound, with the divided tendon ends being indistinct. RESULTS Three phases of healing were apparent on ultrasound assessment at three, six, and twelve weeks after the tenotomy. These sequential phases are similar to those previously described in the healing of tendons with no gap. The transition to normal structure was frequently demonstrated by ultrasonography only at twelve weeks (in thirteen of twenty-one tendons). CONCLUSIONS Although there is evidence of continuity of the Achilles tendon by three weeks after tenotomy, healing is not complete until at least twelve weeks. The time needed for the tendon to completely heal should be taken into consideration before a revision Achilles tenotomy is planned.

Commentary on "Inter- and intrareader variability in the interpretation of two radiographic classification systems for juvenile rheumatoid arthritis"

Published online: 2 August 2003 Springer-Verlag 2003 In this issue of Pediatric Radiology there is an interesting article by Doria et al. [1], which discusses the difficulties of using conventional radiographs for the detection and monitoring of arthritic changes in the paediatric skeleton. Inadvertently, the authors have also highlighted the need for further discussion of nomenclature in childhood arthritis. Pediatric Radiology rightly prides itself on having a worldwide readership. Unfortunately, for radiologists with an interest in childhood arthritis who practice on opposite sides of the Atlantic, imaging of the same disease process is hampered by confusion of nomenclature and classification of their patients. In North America the American College of Rheumatology has formulated criteria to describe childhood arthritis under the term ’juvenile rheumatoid arthritis’ (JRA) [2]. The European League Against Rheumatism (EULAR) has alternative criteria which define childhood arthritides in Europe and use the term ’juvenile chronic arthritis’ (JCA) [3]. Importantly, these two classifications have slightly different subgrouping of the arthritides. In particular, JCA includes the spondyloarthropathies, psoriatic arthropathy and those arthropathies associated with inflammatory bowel disease; these subcategories are not included in JRA. In an effort to bring uniformity to the diagnosis, to aid research and to improve management protocols, the Paediatric Standing Committee of the International League of Associations for Rheumatism (ILAR) has tried to establish a new classification [4]. This new classification uses the label ’juvenile idiopathic arthritis’ (JIA). The term JIA indicates onset before 16 years of age of a disease characterised primarily by arthritis, persisting for at least 6 weeks and currently with no known cause. The different subcategories of JIA are systemic onset, polyarticular (rheumatoid factor positive and negative) oligoarthritis, psoriatic, enthesitis and other arthritides. While there still remains some controversy about the term JIA and further work is needed on disease classification, it is hoped this ’new disease’ will bring world-wide uniformity and improve patient management. While interesting to the radiologist, this new classification has not altered our understanding of the primary pathological process in childhood arthritis or the radiological features. In their study, Doria et al. [1] rightly comment that there is significant intraand interobserver variability when using a scoring system based on conventional radiographs. Other recent studies have also shown that conventional radiographs have a limited role in Pediatr Radiol (2003) 33: 671–672 DOI 10.1007/s00247-003-0957-y COMMENTARY

Paediatric trauma imaging: Why do we need separate guidance?

It is often assumed that the pattern of injury in children mirrors that of the adult population, but children have different anatomical proportions and the relative elasticity of their tissues results in different injury patterns. The authors of this review are members of the British Society of Paediatric Radiologists subgroup and developed the recently published(47) paediatric trauma protocols for imaging children involved in major blunt trauma. The following article has been written to bring these guidelines to the attention of the wider community of UK radiologists, and explain the rationale behind the recommendations.