Imaging of articular disorders in children

Double inversion recovery MRI versus contrast-enhanced MRI for evaluation of knee synovitis in juvenile idiopathic arthritis

BACKGROUND

Double inversion recovery (DIR) MRI has the potential to accentuate the synovium without using contrast agents, as it allows simultaneous signal suppression of fluid and fat. The purpose of this study was (1) to compare DIR MRI to conventional contrast-enhanced (CE) MRI for delineation of the synovium in the knee in children with juvenile idiopathic arthritis (JIA) and (2) to assess the agreement between DIR MRI and CE-MRI regarding maximal synovial thickness measurements.

RESULTS

In this prospective study, 26 children with JIA who consecutively underwent 3.0-T knee MRI between January 2018 and January 2021 were included (presence of knee arthritis: 13 [50%]; median age: 14 years [interquartile range [IQR]: 11-17]; 14 girls). Median confidence to depict the synovium (0-100 mm visual analogue scale; scored by 2 readers [consensus based]) was 88 (IQR: 79-97) for DIR MRI versus 100 (IQR: 100-100) for CE-MRI (p value = < .001). Maximal synovial thickness per child (millimeters; scored by 4 individual readers) on DIR MRI was greater (p value = < .001) in the children with knee arthritis (2.4 mm [IQR: 2.1-3.1]) than in those without knee arthritis (1.4 mm [IQR: 1.0-1.6]). Good inter-technique agreement for maximal synovial thickness per child was observed (r_s = 0.93 [p value = < .001]; inter-reader reliability: ICC DIR MRI = 0.87 [p value = < .001], ICC CE-MRI = 0.90 [p value = < .001]).

CONCLUSION

DIR MRI adequately delineated the synovium in the knee of children with JIA and enabled synovial thickness measurement similar to that of CE-MRI. Our results demonstrate that DIR MRI should be considered as a child-friendly alternative to CE-MRI for evaluation of synovitis in children with (suspected) JIA.

Lead synovitis: The important role of radiology on diagnosis and follow-up: Case report

We present the case report of a 67-year-old man with a history of a firearm injury on the left upper extremity 35 years ago. Lead synovitis and imaging features are reviewed, emphasizing radiology's crucial role in diagnosing and following this condition.

The modified Kocher criteria for septic hip: Does it apply to the knee?

BACKGROUND

Pediatric septic arthritis is a surgical emergency and timely diagnosis prevents serious complications. To differentiate between septic hip and transient synovitis, the predictive value of four original Kocher criteria (fever, inability to bear weight, elevated serum white blood cell count, and elevated erythrocyte sedimentation rate) plus Caird's addition of elevated C-reactive protein have been studied, termed the modified Kocher criteria. These criteria have not been tested extensively on septic knee. This study tested the utility of the modified Kocher criteria in predicting septic knee while validating it for septic hip.

METHODS

A retrospective chart review was conducted of pediatric patients evaluated at a single institution for irritable hip or knee between 2009 and 2018. Patients who underwent arthrocentesis were included and the modified Kocher criteria were applied to all.

RESULTS

One hundred fifty-five patients (96 hips and 59 knees) were identified. One hundred four (67.1%) patients had septic arthritis with 44/59 (74.6%) of knees and 60/96 (62.5%) of hips. The strongest predictors for septic hip and knee were elevated C-reactive protein (odds ratio = 26.9, p < 0.0001) and refusal to bear weight (odds ratio = 14.5, p < 0.0001), respectively. For hips, 5/5 criteria produced a 100% positive predictive value for septic arthritis. For knees, the combination of inability to bear weight and elevated C-reactive protein had a positive predictive value of 89.7%.

CONCLUSION

While all five of the modified Kocher criteria are not predictive of pediatric septic knee, the combination of two specific factors (inability to bear weight and elevated C-reactive protein) is strongly predictive. This study validates previous work that the modified Kocher criteria are predictive of septic hip.

LEVEL OF EVIDENCE

level III.

Classifications and imaging of juvenile spondyloarthritis

Juvenile spondyloarthritis may be present in at least 3 subtypes of juvenile idiopathic arthritis according to the classification of the International League of Associations for Rheumatology. By contrast with spondyloarthritis in adults, juvenile spondyloarthritis starts with inflammation of peripheral joints and entheses in the majority of children, whereas sacroiliitis and spondylitis may develop many years after the disease onset. Peripheral joint involvement makes it difficult to differentiate juvenile spondyloarthritis from other juvenile idiopathic arthritis subtypes. Sacroiliitis, and especially spondylitis, although infrequent in childhood, may manifest as low back pain. In clinical practice, radiographs of the sacroiliac joints or pelvis are performed in most of the cases even though magnetic resonance imaging offers more accurate diagnosis of sacroiliitis. Neither disease classification criteria nor imaging recommendations have taken this advantage into account in patients with juvenile spondyloarthritis. The use of magnetic resonance imaging in evaluation of children and adolescents with a clinical suspicion of sacroiliitis would improve early diagnosis, identification of inflammatory changes and treatment. In this paper, we present the imaging features of juvenile spondyloarthritis in juvenile ankylosing spondylitis, juvenile psoriatic arthritis, reactive arthritis with spondyloarthritis, and juvenile arthropathies associated with inflammatory bowel disease.

Imaging in paediatric rheumatology: Is it time for imaging?

Juvenile idiopathic arthritis (JIA) is a heterogeneous group of arthritides characterized by chronic synovial inflammation that can lead to structural damage. The main objective of JIA therapies is to induce disease control to avoid disability in childhood. The advances in therapeutic effectiveness have created a need to search for imaging tools that describe more precisely disease activity in children with JIA. Musculoskeletal ultrasound and magnetic resonance imaging have demonstrated to be more sensitive than clinical examination in early detection of synovitis. These modalities can detect both inflammatory and destructive changes. The unique characteristics of the growing skeleton and a scarce validation of imaging in children result in important challenges in evaluating paediatric population. This review describes indications and limitations of these imaging techniques and suggests some advices for a rational use in the management of JIA in clinical practice.

Emergency Department Point-of-Care Hip Ultrasound and Its Role in the Diagnosis of Septic Hip Arthritis: A Case Report

We present a case of an 11-year-old girl with eye swelling and hip pain and the use of point-of-care hip ultrasound (US) to facilitate diagnosis of a septic hip. We review the US technique, sonographic findings, and relevant literature regarding point-of-care hip US.

Ultrasound in juvenile idiopathic arthritis

BACKGROUND

In the recent years, musculoskeletal ultrasound (MSUS) has been regarded as especially promising in the assessment of juvenile idiopathic arthritis (JIA), as a reliable method to precisely document and monitor the synovial inflammation process.

MAIN CONTENT

MSUS is particularly suited for examination of joints in children due to several advantages over other imaging modalities. Some challenges should be considered for correct interpretation of MSUS findings in children, due to the peculiar features of the growing skeleton. MSUS in JIA is considered particularly useful for its ability to detect subclinical synovitis, to improve the classification of patients in JIA subtypes, for the definition of remission, as guidance to intraarticular corticosteroid injections and for capturing early articular damage. Current evidence and applications of MSUS in JIA are documented by several authors. Recent advances and insights into further investigations on MSUS in healthy children and in JIA patients are presented and discussed in the present review.

CONCLUSIONS

MSUS shows great promise in the assessment and management of children with JIA. Nonetheless, anatomical knowledge of sonographic changes over time, underlying immunopathophysiology, standardization and validation of MSUS in healthy children and in patients with JIA are still under investigation. Further research and educational efforts are required for expanding this imaging modality to more clinicians in their daily practice.

Basic radiological assessment of synovial diseases: a pictorial essay

The synovium is a specialized tissue lining the synovial joints, bursae, and tendon sheaths of the body. It is affected by various localized or systemic disorders. Synovial diseases can be classified as inflammatory, infectious, degenerative, traumatic, hemorrhagic, and neoplastic. Damage in other intraarticular structures, particularly cartilages, generally occurs as a part of pathologic processes involving the synovium, leading to irreversible joint destruction. Imaging has an essential role in the early detection of synovial diseases prior to irreversible joint damage. Obtaining and understanding characteristic imaging findings of synovial diseases enables a proper diagnosis for early treatment. This article focuses on the recent literature that is related with the role of imaging in synovial disease.

Clinical approach to fever of unknown origin in children

BACKGROUND/PURPOSE

Fever of unknown origin (FUO) can be caused by many clinical conditions and remains a diagnostic challenge in clinical practice. The etiology of FUO varies markedly among different age groups, geographic areas, and seasons. A four-stage investigative protocol for FUO is widely applied in clinical practice. The aim of this study was to evaluate the usefulness of this four-stage protocol for identifying the etiology of FUO in children.

METHODS

We enrolled children younger than 18 years of age who were admitted to the Taichung Veterans General Hospital during the period from January 2006 to December 2014 with FUO persisting for more than 3 weeks. The four-stage FUO investigative guideline was used to evaluate the etiology of fever in all patients enrolled in the study.

RESULTS

The etiology of FUO was identified in 79 (84.9%) of the 93 patients enrolled in the study. The most common cause of FUO was infectious disease (37.6%), followed by malignancy (17.2%), miscellaneous disease (16.1%), and collagen vascular disease (14.0%). With respect to the four-stage survey of FUO, 36 of the 79 patients (45.6%) were identified in Stage 3, 28 patients (35.4%) in Stage 2, 13 patients (16.5%) in Stage 4, and only two patients (2.5%) in Stage 1.

CONCLUSION

A well-designed systemic review of the epidemiological information, medical history, physical examination, laboratory analysis, and adequate invasive procedures provide adequate data to identify the most common causes of FUO in children.

Contrast-enhanced MRI features in the early diagnosis of Juvenile Idiopathic Arthritis

Objectives

To determine whether clinical, laboratory or Magnetic Resonance Imaging (MRI) measures differentiate Juvenile Idiopathic Arthritis (JIA) from other forms of active childhood arthritis.

Materials and methods

We prospectively collected data of 80 treatment-naïve patients clinically suspected of JIA with active non-infectious arthritis of (at least) one knee for <12 months duration. Upon presentation patients underwent clinical and laboratory assessments and contrast-enhanced MRI. MRI was not used as a diagnostic criterion.

Results

Forty-four (55 %) patients were clinically diagnosed with JIA, whereas in 36 (45 %) patients the diagnosis of JIA was discarded on clinical or laboratory findings. MRI-based synovitis was present in 27 (61.4 %) JIA patients and in 7 (19.4 %) non-JIA patients (P < 0.001).

Five factors (male gender, physician’s global assessment of overall disease activity, joints with limited range of motion, HLA-B27, MRI-based synovitis) were associated with the onset of JIA. In multivariate analysis MRI-based synovitis proved to be independently associated with JIA (OR 6.58, 95 % CI 2.36-18.33). In patients with MRI-based synovitis, the RR of having JIA was 3.16 (95 % CI 1.6-6.4).

Conclusions

The presence of MRI-based synovitis is associated with the clinical onset of JIA. Physical examination could be supported by MRI, particularly to contribute in the early differentiation of different forms of non-infectious childhood arthritis.

Key points

• Juvenile Idiopathic Arthritis (JIA) is a diagnosis of exclusion.

• Differentiating JIA and other forms of childhood arthritis can be difficult.

• MRI-techniques have substantially improved evaluation of joint abnormalities in JIA patients.

• MRI-based synovitis is significantly associated with the clinical onset of JIA.

• MRI could support physical examination in the early differentiation of childhood arthritis.

Imaging in juvenile idiopathic arthritis (JIA): an update with particular emphasis on MRI

Juvenile idiopathic arthritis (JIA) is a heterogeneous condition encompassing all forms of chronic arthritis of unknown origin and with onset before 16 years of age. During the last decade new, potent therapeutic agents have become available, underscoring the need for accurate monitoring of therapeutic response on both disease activity and structural damage to the joint. However, so far, treatment efficacy is based on clinical ground only, although clinical parameters are poor markers for disease activity and progression of structural damage. Not so for rheumatoid arthritis patients where the inclusion of radiographic assessment has been required by FDA to test the disease-modifying potential of new anti-rheumatic drugs. In imaging of children with JIA there has been a shift from traditional radiography towards newer techniques such as ultrasound and MRI, however without proper evaluation of their accuracy and validity. We here summarize present knowledge and discuss future challenges in imaging children with JIA.

Advances and challenges in imaging in juvenile idiopathic arthritis

Imaging assessments of the joints of children with juvenile idiopathic arthritis (JIA) are challenging, owing to the unique features of the growing skeleton. Traditionally, imaging studies in childhood arthritis have been based on conventional radiography. However, in the past few years, interest in the use of MRI and ultrasonography has increased. As a result, imaging has become a main area of clinical and research investigation in paediatric rheumatology. The chief advance in the field of conventional radiography has been the development and validation of paediatric scoring systems for the assessment of radiographic progression. Several studies have shown that MRI provides a precise quantification of synovitis in children with JIA. Furthermore, a high frequency of bone marrow oedema and bone erosions has been found early in the disease course. Ultrasonography has been proven to be superior to clinical examination in detecting synovitis, tenosynovitis and enthesitis. A high frequency of subclinical synovitis has been demonstrated in patients with JIA who have clinically inactive disease using both MRI and ultrasonography. However, more information from healthy children is needed to enable differentiation of the bone and cartilage abnormalities that reflect damage from those that are part of normal development using MRI or ultrasonography. This Review provides a summary of the current information on conventional radiography, ultrasonography and MRI in JIA and highlights the advantages and limitations of each imaging modality.

Musculoskeletal ultrasound in pediatric rheumatology

Although musculoskeletal ultrasound (MSUS) has emerged as an indispensible tool among physicians involved in musculoskeletal medicine in the last two decades, only recently has it become more attractive to pediatric rheumatologists. Thereafter, the use of MSUS in pediatric rheumatology has started to increase. Yet, an ever-growing body of literature shows parity and even superiority of MSUS when compared to physical examination and other imaging modalities.MSUS is suitable for examination of children of all ages and it has certain advantages over other imaging modalities; as it is cheaper, mobile, instantly accessible bedside, easy to combine with clinical assessment (interactivity) and non-invasive. It does not require sedation, which facilitates repetitive examinations. Assessment of multiple locations is possible during the same session. Agitation is rarely a problem and small children can be seated in their parents' lap or they can even play while being examined.

MR findings of synovial disease in children and young adults: Part 1

Synovial diseases in children can be classified into normal structures as potential sources of pathology (synovial folds: plicae, infrapatellar fat pad clefts); noninfectious synovial proliferation (juvenile idiopathic arthritis, hemophilic arthropathy, lipoma arborescens, synovial osteochondromatosis, pigmented villonodular synovitis, reactive synovitis), and infectious synovial proliferation, deposition disease, vascular malformations, malignancy (including metastasis) and intra-articular/periarticular cysts and cyst-like structures (ganglia). Familiarity with characteristic MR imaging findings of synovial diseases in children and young adults will enable a more confident diagnosis for earlier intervention and directed therapy. The first part of this paper will cover potential pathology of normal synovial structures as well as noninfectious synovial proliferation.

Differences in MRI findings between subgroups of recent-onset childhood arthritis

BACKGROUND

MRI is sensitive for joint inflammation, but its ability to separate subgroups of arthritis in children has been questioned. Infectious arthritis (IA), postinfectious arthritis (PA), transient arthritis (TA) and juvenile idiopathic arthritis (JIA) are subgroups that may need early, different treatment.

OBJECTIVE

To determine whether MRI findings differ in IA, PA/TA and JIA in recent-onset childhood arthritis.

MATERIALS AND METHODS

Fifty-nine children from a prospective study of incidence of arthritis (n = 216) were, based on clinical and biochemical criteria, examined by MRI. Joint fluid, synovium, bone marrow, soft tissue and cartilage were scored retrospectively and analysed by Pearson chi-square test and logistic regression analysis.

RESULTS

Fifty-nine children had MRI of one station. IA was suggested by bone marrow oedema (OR 7.46, P = 0.011) and absence of T1-weighted and T2-weighted low signal intensity synovial tissue (OR 0.06, P = 0.015). Furthermore, soft-tissue oedema and reduced contrast enhancement in the epiphyses were more frequent in children with IA. JIA correlated positively with low signal intensity synovial tissue (OR 13.30, P < 0.001) and negatively with soft-tissue oedema (OR 0.20, P = 0.018). No significant positive determinants were found for PA/TA, but bone marrow oedema, soft-tissue oedema, irregular thickened synovium and low signal intensity synovial tissue was less frequent than in IA/JIA.

CONCLUSION

In children with high clinical suspicion of recent onset arthritis, there was a significant difference in the distribution of specific MRI features among the diagnostic groups.

Synovial and inflammatory diseases in childhood: role of new imaging modalities in the assessment of patients with juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) represents a group of heterogeneous diseases characterized by a chronic inflammatory process primarily targeting the synovial membrane. A persistent synovitis is associated with an increased risk of osteocartilaginous damage.With the advent of effective structure-modifying treatment for JIA, it may be possible to significantly reduce or even completely prevent structural damage and associated functional disability. The trend towards early suppression of inflammation, in order to prevent erosive disease, shifts the emphasis away from conventional radiographic detectable structural damage to the slightest traces of early joint damage, and drives the need for alternative imaging techniques more sensitive in detecting early signs of disease activity and damage. In this regard MRI and US are playing an increasing role in the evaluation of arthritic joints.This article will review the key aspects of the current status and recent important advances of imaging techniques available to investigate the child with rheumatic disease, briefly discussing conventional radiography, and particularly focusing on MRI and US. In this era of advancing imaging technology, knowledge of the relative values of available imaging techniques is necessary to optimize the management of children with JIA.

Characterization of a small animal growth plate injury model using microcomputed tomography

Injuries to the growth plate remain a significant clinical challenge. The need to better understand mechanisms of growth disruption following transphyseal injuries and evaluate new therapeutic approaches to growth restoration motivates development of a well characterized model of growth plate injury. The goals of this study were to develop a growth plate defect model in the rat and to use microcomputed tomography (micro-CT) imaging to detect and quantify associated changes in growth plate morphology and mineralization over time following injury and in response to treatment. Three-dimensional images of the growth plate were created from micro-CT scans and used to quantify the volume of mineralized tissue within the defect site. Growth plate thickness and volume as well as the degree of growth plate fusion were also measured from the reconstructed 3D images. Growth deficiency was then quantified as a function of time post-injury from whole limb micro-CT scans. Finally, this model was used to determine the ability of an injectable in situ gelling hydrogel to prevent formation of a bony bridge within the defect and the subsequent effect on limb length deficiency and changes to growth plate morphology. Growth plate injury resulted in significant shortening of the defect limb by day 28 and significant thinning and fusion of the surrounding growth plate up to day 112. Limb length reduction was correlated with changes in the growth plate volume and average thickness at day 56. Injection of an in situ gelling agarose into the defect resulted in a reduction of limb length discrepancy as well as a thicker growth plate on average compared to empty defect controls. These results establish a novel method of characterizing changes in whole bone and growth plate morphology due to a growth plate injury and indicate that treatment with agarose hydrogel reduces limb length discrepancy but is not sufficient to regenerate growth plate tissue or fully restore growth function.

Approach to knee effusions

The presence of an intra-articular knee effusion requires an extensive differential diagnosis and a systematic diagnostic approach. Pediatric knee effusions occur most commonly as acute hemarthroses after traumatic injury. However, the knee joint is susceptible to effusions secondary to a wide variety of atraumatic causes. Special attention is required in the atraumatic effusion to distinguish features of infectious, postinfectious, rheumatologic, hematologic, vasculitic, and malignant disease. This review discusses the various etiologies of both traumatic and atraumatic pediatric knee effusions highlighting the historical, physical examination, and laboratory characteristics to aid the emergency provider in diagnosis and initial management.

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.

MRI findings of juvenile psoriatic arthritis

OBJECTIVE

The aim of this study was to describe the magnetic resonance imaging (MRI) features of juvenile psoriatic arthritis (JpsA) in children in order to facilitate early diagnosis and proper management.

MATERIALS AND METHODS

Two pediatric radiologists retrospectively reviewed in consensus a total of 37 abnormal MRI examinations from 31 pediatric patients (nine boys, 22 girls; age range 1-17 years; mean age 9.4 years) who had a definite diagnosis of JpsA and underwent MRI. Each MRI was evaluated for synovium abnormality (thickening and enhancement), joint effusion (small, moderate, and large), bone marrow abnormality (edema, enhancement, and location of abnormality), soft tissue abnormality (edema, enhancement, atrophy, and fatty infiltration), tendon abnormality (thickening, edema, tendon sheath fluid, and enhancement), and articular abnormality (joint space narrowing and erosion). The distribution of abnormal MRI findings among the six categories for the 37 MRI examinations was evaluated. The number of abnormal MRI findings for each MRI examination was assessed. Age at MRI examination and all six categories of abnormal MRI findings according to gender were evaluated.

RESULTS

There were a total 96 abnormal MRI findings noted on 37 abnormal MRI examinations from 31 pediatric patients. The 37 abnormal MRI examinations included MRI of the hand (n = 8), knee (n = 8), ankle (n = 5), pelvis (n = 5), temporomandibular joint (n = 4), wrist (n = 3), foot (n = 2), elbow (n = 1), and shoulder (n = 1). Twenty-eight diffuse synovial thickening and/or enhancement were the most common MRI abnormality (29.2%). Joint effusion comprised 22 abnormal MRI findings (22.9%). There were 16 abnormal MRI bone marrow edema and/or enhancement findings (16.7%), and in seven (7.3%) the edema involved non-articular sites. Soft tissue abnormality manifested as edema and/or enhancement constituted 14 abnormal MRI findings (14.5%). There were ten MRI abnormalities (10.4%) involving tendons. Articular abnormality seen as joint space narrowing and/or bone erosion comprised six abnormal MRI findings (6.2%). Most MRI examinations had more than one abnormal finding (84%). Age at which MRI examinations were performed was not significantly different between boys and girls. All six categories of abnormal MRI findings were not significantly different between boys and girls.

CONCLUSION

Children with JpsA typically present with more than one abnormal finding on their MRI studies. While synovial abnormality is the most common MR finding in children with JpsA, multi-focal bone marrow edema and enhancement at both articular and non-articular sites are also notable findings in children with JpsA. The rate of articular abnormality is much lower in children with JpsA in comparison to adults with psoriatic arthritis. Our findings suggest that MRI can play a useful role in the diagnosis and ongoing assessment of this uncommon, though important, pediatric rheumatologic disorder.

Pediatric musculoskeletal MRI: basic principles to optimize success

The purpose of this general review is to suggest practical strategies to optimize musculoskeletal MR imaging in children. The changes related to ossification and marrow transformation affect the MRI appearance during development. This review summarizes the normal appearance of the growing skeleton on various pulse sequences, as well as ways to optimize the imaging parameters. Appropriate patient positioning, choice of field of view and imaging coils are essential. There are various tools including intravenous contrast agent administration, fat suppression and parallel imaging that can enhance the depiction of abnormalities, increase speed of imaging, and improve overall quality of the study. Finally, special considerations for imaging at 3 T are also reviewed.

Spondyloarthropathy presenting at a young age: case report and review

The diagnosis of juvenile spondyloarthritis (JSA) is rarely entertained in young children who present with back and leg pain. We present a case of a 6-year-old male who presented with a 3-year history of severe back and leg pain and a positive Gower's sign, and was given a presumed diagnosis of muscular dystrophy. Presenting serologic evaluation included a mildly elevated sedimentation rate and C-reactive protein (CRP). Computed tomography of the pelvis demonstrated large erosions affecting both sacro-iliac joints. Despite the unusually young age of this patient, ankylosing spondylitis seemed the most plausible diagnosis. Following rheumatological evaluation and treatment for JSA, he showed significant clinical improvement. His disease, however, has not entirely remitted with signs of enthesitis at the Achilles tendon and knees. We present this case to illustrate that JSA could account for symptoms at an early age and not considering it could lead to multiple medical visits and diagnoses. To our knowledge, based on a search of the World literature, this would appear to be the youngest case of JSA reported with demonstrable severe sacroiliitis.

Imaging of Back Pain in Children and Adolescents

PURPOSE

To present the imaging findings of the wide spectrum of musculoskeletal diseases causing back pain in children and adolescents.

DISCUSSION

Back pain in children is a rare condition but may denote a serious health problem; hence, full clinical history, physical examination, and appropriate laboratory studies should be obtained. In this scientific exhibit, we present the imaging findings of the variable musculoskeletal diseases that are associated with back pain in children and adolescents. These disease processes include scoliosis of various causes; spondylolysis; spondylolisthesis; traumatic injuries; disc degeneration and herniation; Scheuermann's disease; spondylodiscitis; tumors (primary, secondary, hematogenous); and miscellaneous conditions (eg, metabolic disorders, sickle cell disease, osteoporosis).

CONCLUSION

A wide spectrum of diseases causing back pain in children is presented. Radiologists should be aware of the imaging findings of this rather uncommon entity to help in reaching the appropriate diagnosis.

Acute Monarthritis: Diagnosis and Management

The diagnosis for an acute monarthritis may still be elusive, even after an extensive initial evaluation. For example, what should be done for a patient who has a paucity of extra-articular findings on physical examination and an inflammatory synovial fluid with negative Gram's stain, cultures, and crystals? Conservative management is always prudent. Assume the joint is infected and treat as such until proven otherwise, because infection carries the highest morbidity and mortality of all the common acute monarthopathies.

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.

Magnetresonanztomographie und -arthrographie des Hüftgelenks

Plain film radiographs represent the imaging of choice for the initial evaluation of pathologies of the hip. However, many lesions of the joint itself and surrounding soft tissues are often not visualized by conventional radiographs. Magnetic resonance imaging (MRI) demonstrates most of these pathologies with high sensitivity and specificity. For further assessment of intra-articular lesions such as labral tears, hyaline cartilage lesions, rupture of the ligamentum teres, and loose bodies, direct MR arthrography after intra-articular administration of contrast medium may be indicated. This article summarizes the technical aspects and the most important indications for MRI and MR arthrography of the hip in correlation with typical imaging findings of the most frequent pathologies.