High-signal T2 changes of the bone marrow of the foot and ankle in children: red marrow or traumatic changes?

Normal skeletal development and imaging pitfalls of the calcaneal apophysis: MRI features

OBJECTIVE

Heel pain in children and secondary MR imaging (MRI) of the hindfoot have been increasing in incidence. Our purpose is to illustrate the, previously unreported, MRI stages in development of the posterior calcaneal apophysis, with attention to imaging pitfalls. This should aid in distinguishing normal growth from true disease.

MATERIAL AND METHODS

Consecutive ankle MRIs in children <18 years, from 2008-2014, were subdivided into 0≤5, 5≤10, 10≤15 and 15≤18 age groups and retrospectively reviewed for development of the calcaneal apophysis.

RESULTS

204 ankle MRI studies in 188 children were identified. 40 studies were excluded with final cohort of 164 studies in 154 patients (82 boys, 72 girls). The calcaneal apophysis was cartilaginous until age 5. Foci of decreased as well as increased signal were embedded in cartilage, prior to ossification. Early, secondary ossification centers appeared in plantar third of the apophysis in 100% of children by age 7. Increased T2 signal in the ossifications was seen in 30% of children. Apohyseal fusion began at 12 and was complete in 78% of 14≤15 year olds and in 88% of 15≤18 year olds. Curvilinear low signal in the ossification centers, paralleling, but distinguished from growth plate, and not be confused with fracture line, was common.

CONCLUSION

Development of the posterior calcaneus follows a unique sequence. Apophyseal fusion occurs earlier than reported in the literature. Familiarity with this maturation pattern, in particular the apophyseal increased T2 signal and the linear low signal paralleling the growth plate, will avoid misinterpreting it for pathology.

Whole-body MRI of juvenile spondyloarthritis: protocols and pictorial review of characteristic patterns

Spondyloarthritides are a group of inflammatory rheumatological diseases that cause arthritis with a predilection for spinal or sacroiliac involvement in addition to a high association with HLA-B27. Juvenile spondyloarthritis is distinct from adult spondyloarthritis and manifests more frequently as peripheral arthritis and enthesitis. Consequently juvenile spondyloarthritis is often referred to as enthesitis-related arthritis (ERA) subtype under the juvenile idiopathic arthritis (JIA) classification criteria. The American College of Rheumatology Treatment Recommendations for JIA, including ERA, are based on the following clinical parameters: current treatment, disease activity and the presence of poor prognostic features. The MRI features of juvenile spondyloarthritis include marrow edema, peri-enthesal soft-tissue swelling and edema, synovitis and joint or bursal fluid. Marrow edema is nonspecific and can be seen with other pathologies as well as in healthy subjects, and this is an important pitfall to consider. With further longitudinal study and validation, however, whole-body MRI with dedicated images of the more commonly affected areas such as the spine, sacroiliac joints, hips, knees, ankles and feet can serve as a more objective tool compared to clinical exam for early detection and monitoring of disease activity and ultimately direct therapeutic management.

Acute fractures of the pediatric foot and ankle

BACKGROUND

Injuries around the foot and ankle are challenging. There is a paucity of literature, outside that of specialist orthopedic journals, that focuses on this subject in the pediatric population.

DATA SOURCES

In this review, we outline pediatric foot and ankle fractures in an anatomically oriented manner from the current literature. Our aim is to aid the emergency department doctor to manage these challenging injuries more effectively in the acute setting.

RESULTS

These injuries require a detailed history and examination to aid the diagnosis. Often, plain radiographs are sufficient, but more complex injuries require the use of magnetic resonance imaging. Treatment is dependent on the proximity to skeletal maturity and the degree of displacement of fracture. Children have a marked ability to remodel after fractures and therefore mainstay treatment is immobilization by a cast or splint. Operative fixation, although uncommon in this population, may be necessary with adolescents, certain unstable injuries or in cases with displaced articular surface. In the setting of severe foot trauma, skin compromise and compartment syndrome of the foot must be excluded.

CONCLUSION

The integrity of the physis, articular surface and soft tissues are all equally important in treating these injuries.

Tibial stress changes in new combat recruits for special forces: patterns and timing at MR imaging

PURPOSE

To characterize the incidence, location, grade, and patterns of magnetic resonance (MR) imaging findings in the tibia in asymptomatic recruits before and after 4-month basic training and to investigate whether MR imaging parameters correlated with pretraining activity levels or with future symptomatic injury.

MATERIALS AND METHODS

This study was approved by three institutional review boards and was conducted in compliance with HIPAA requirements. Volunteers were included in the study after they signed informed consent forms. MR imaging of the tibia of 55 men entering the Israeli Special Forces was performed on recruitment day and after basic training. Ten recruits who did not perform vigorous self-training prior to and during service served as control subjects. MR imaging studies in all recruits were evaluated for presence, type, length, and location of bone stress changes in the tibia. Anthropometric measurements and activity history data were collected. Relationships between bone stress changes, physical activity, and clinical findings and between lesion size and progression were analyzed.

RESULTS

Bone stress changes were seen in 35 of 55 recruits (in 26 recruits at time 0 and in nine recruits after basic training). Most bone stress changes consisted of endosteal marrow edema. Approximately 50% of bone stress changes occurred between the middle and distal thirds of the tibia. Lesion size at time 0 had significant correlation with progression. All endosteal findings smaller than 100 mm resolved or did not change, while most findings larger than 100 mm progressed. Of 10 control subjects, one had bone stress changes at time 0, and one had bone stress changes at 4 months.

CONCLUSION

Most tibial bone stress changes occurred before basic training, were usually endosteal, occurred between the middle and distal thirds of the tibia, were smaller than 100 mm, and did not progress. These findings are presumed to represent normal bone remodeling.

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.

Magnetic resonance imaging of the immature skeleton

Magnetic resonance (MR) is unique in its ability to allow assessment of bone marrow, epiphyseal, physeal, and articular cartilage as well as tendons and ligaments. An understanding of skeletal maturation and the accompanying changes on MR is of utmost importance in pediatric radiology. In particular, it is important to recognize the normal spectrum related to ossification and marrow transformation. This review will include a brief description of main indications and common pitfalls in musculoskeletal MR in children. Also, we will focus on the MR appearance of the growing pediatric skeleton on the most commonly used sequences.

Advances in pediatric oncology MRI

Refined stratification of disease is thought to result in better survival from childhood malignant disease while minimizing the adverse effects of anticancer therapies. There is a potential for magnetic resonance imaging (MRI) to contribute to such stratification by improved tissue characterization, anatomical depiction, staging, and assessment of early treatment response. Recent advances in pediatric MRI outside the central nervous system (CNS) are reviewed in this context. The focus is on new applications for conventional MRI and on clinical implementation of tissue-specific and quantitative techniques. This area is largely unexplored, and potential directions for research are indicated.

Pediatric and adolescent intra-articular fractures of the calcaneus

Calcaneal fractures in childhood are very rare, whereas particularly intra-articular displaced fractures are not typical in skeletally immature children. Various techniques of osteosynthesis have been described. This study aimed to determine clinical and radiological outcome after surgical treatment of intraarticular calcaneal fractures. Fourteen intraarticular fractures of the calcaneus were included in this retrospective study. Eleven children (2 girls and 9 boys) aged 6-16 years (average age 11.5 years) underwent surgical treatment. One child sustained a Type II open fracture of both calcanei. All injuries occurred after a high-energy trauma; 3 patients had multiple additional fractures. The clinical and radiological postoperative follow up was an average 44 months. In 4 cases, a reduction through a minimally invasive approach and fixation with K-wires or screws could be achieved. Eleven fractures were treated with open reduction and internal fixation with plate osteosynthesis, K-wires or screws. In one case with open fractures of both heel bones, an additional external fixator was applied. The surgical treatment approach adopted enabled the pre-operative Böhler’s angle (average 16°) to be improved to an average 30°. In all cases, except for the patient with open fractures, a good functional result and outcome could be achieved. In calcaneal fractures in childhood, anatomical reduction is the determining factor, as in fractures in adults, whereas the surgical technique seems to have no influence on clinical outcome in children. The wound healing problems that have often been described were not observed in this age group.

Marrow: red, yellow and bad

Bone marrow is one of the largest and most dynamic tissues in the body, and it is well-depicted on conventional MRI sequences. However, often only perfunctory attention is paid to the bone marrow on musculoskeletal imaging studies, raising the risk of delayed or missed diagnoses. To guide appropriate recognition of normal variants and pathological processes involving the marrow compartment, this article describes and depicts the physiological spatiotemporal pattern of conversion of hematopoietic red marrow to fatty yellow marrow during childhood and adolescence, and the characteristic imaging findings of disorders involving marrow hyperplasia/reconversion, marrow infiltration/deposition and marrow depletion/failure.

MR imaging of the paediatric foot and ankle

Radiography is the mainstay for initial evaluation of paediatric foot and ankle pathology. MRI is the preferred exam for further characterisation of the majority of these conditions. The modality features high sensitivity and specificity for this purpose with few exceptions. Findings on MRI will often dictate patient referral and further management, and are frequently required for surgical planning. This article will provide an overview of a variety of pathologies that afflict the foot and ankle in children. These include tarsal coalition, osteochondral lesions, osteonecrosis, osteochondroses, stress fractures, osteomyelitis, inflammatory arthritis, neoplasms of bone and soft tissue, and foreign bodies. Their respective imaging manifestations on MRI are the focus of the paper. Technical parameters and marrow signal variation are also discussed.

Value of MRI in diagnosing injuries after ankle sprains in children

BACKGROUND

To our knowledge, there are only a few prospective studies on the use of magnetic resonance imaging (MRI) to diagnose injuries associated with ankle sprains in children. We hypothesized that MRI examinations of acute ankle sprains in growing children would show relevant injuries that may have been overlooked by conventional clinical, radiological, and ultrasound examinations.

METHODS

Thirty children with acute inversion injury of the ankle were subjected to an MRI examination of the ankle joint, in addition to conventional radiographic procedures. All data were recorded prospectively. Depending on the severity of the clinical symptoms, the children were divided into three different groups. Children with little soft-tissue swelling and who were still able to walk were assigned to Group I (n = 10), Group II consisted of children who were only partially able to walk and had moderate soft-tissue swelling (n = 12), while Group III consisted of the children who were not able to walk and had pronounced soft-tissue swelling (n = 8). Regular followup examinations were carried out. At the final followup examination, on average 8 months after injury, the children in Groups II and III were again examined by MRI. The clinical results were compared and correlated with the results of the MRI examinations.

RESULTS

Altogether, torn ligaments could be verified in 23 out of 30 of the cases; bony avulsions were found in 10% of these. Three of 30 patients had a Salter I injury. Bone bruising was found in 18 out of 30 (60%). Bone bruising was most commonly found near the medial talus. MRI examination of the patients in Group I showed no more ruptures than the clinical examination; here, only four patients were found to have partial ruptures of the ATL. In Group II, torn ligaments were found in six out of 12 (50%) of the cases; similarly, Salter I injuries were found in three out of 12 cases. The patients in Group III also showed serious injuries on the MRI examination. Bone bruising, torn ligaments, or bony avulsions were found in eight out of eight (100%) cases. The recorded clinical results showed only weak correlation to the injury patterns diagnosed using MRI. Only the bone bruises correlated with clinical results. Children with more pronounced swelling and less ability to walk were more commonly diagnosed with bone bruises. No differences were found between groups with regard to pain, instability, or limitations of mobility in the followup examinations or the final MRI examination 8 months after injury.

CONCLUSION

The injury patterns diagnosed through MRI examination did not correlate with clinical findings. With adequate progressive rehabilitation, the pathological changes diagnosed with MRI healed without further complications. MRI examinations of acute ankle distortion injuries in children did not result in any additional therapeutic value. Therefore, we believe conventional clinical, radiological, and ultrasound diagnostic methods are sufficient for the primary diagnosis of ankle fractures and ankle ligament injuries in children.

Comparison of ultrasonography with Doppler and MRI for assessment of disease activity in juvenile idiopathic arthritis: a pilot study

BACKGROUND

In juvenile idiopathic arthritis (JIA), the trend towards early therapeutic intervention and the development of new highly effective treatments have increased the need for sensitive and specific imaging. Numerous studies have demonstrated the important role of MRI and US in adult rheumatology. However, investigations of imaging in JIA are rare, and no previous study has been comparing MRI with Doppler ultrasonography (US) for assessment of arthritis. The aim of the present study was to compare the two imaging methods regarding their usefulness for evaluating disease activity in JIA, and to compare the results with those obtained in healthy controls.

METHODS

In 10 JIA patients (median age 14 years, range 11-18), 11 joints (six wrists, three knees, two ankles) with arthritis were assessed by color Doppler US and MRI. The same imaging modalities were used to evaluate eight joints (three wrists, three knees, two ankles) in six healthy age- and sex-matched controls. The US examinations of both the patients and controls were compared with the MRI findings.

RESULTS

In 10 JIA patients, US detected synovial hypertrophy in 22 areas of 11 joints, 86% of which had synovial hyperemia, and MRI revealed synovitis in 36 areas of the same 11 joints. Erosions were identified by US in two areas of two joints and by MRI in six areas of four joints. Effusion was shown by US in nine areas of six joints and by MRI in 17 areas of five joints. MRI detected juxta-articular bone marrow edema in 16 areas of eight joints.

CONCLUSIONS

The results of this pilot study indicate that both MRI and US provide valuable imaging information on disease activity in JIA. Importantly, the two techniques seem to complement each other and give partly different information. Although MRI is considered to be the reference standard for advanced imaging in adult rheumatology, US seems to provide useful imaging information that could make it an option in daily clinical practice, in JIA as well as in adult rheumatology. However, the current work represents a pilot study, and thus our results need to be confirmed in a larger prospective clinical investigation.

Taking the stress out of evaluating stress injuries in children

Pediatric stress injuries result from a mismatch between (a) the burden of activity on growing bone and cartilage and (b) their intrinsic biomechanical properties. Although the presentation of stress injuries varies with the specific physical activity and the site of injury, in children it varies primarily with the degree of skeletal maturation. During the past several years, there has been a substantial increase in the incidence of pediatric stress injuries. The differential diagnosis of a stress injury in a child or adolescent can be challenging because the injury sometimes can appear aggressive at imaging assessment. Awareness of the spectrum of imaging features of stress injuries can help the radiologist to reach the correct diagnosis and prevent unnecessary anxiety. This review depicts the range of stress injuries in children and adolescents in various anatomic locations, with emphasis on their appearances at magnetic resonance imaging.

MRI assessment of bone marrow in children with juvenile idiopathic arthritis: intra- and inter-observer variability

BACKGROUND

Bone marrow oedema (BMO) is included in MRI-based scoring systems of disease activity in adults with rheumatoid arthritis. Similar systems in juvenile idiopathic arthritis (JIA) are lacking.

OBJECTIVE

To assess the reproducibility in a multi-centre setting of an MRI BMO scoring system in children with JIA.

MATERIALS AND METHODS

Seventy-six wrist MRIs were read twice, independently, by two experienced paediatric radiologists. BMO was defined as ill-defined lesions within the trabecular bone, returning high and low signal on T2- and T1-weighted images respectively, with or without contrast enhancement. BMO extension was scored for each of 14 bones at the wrist from 0 (none) to 3 (extensive).

RESULTS

The intra-observer agreement was moderate to excellent, with weighted kappa ranging from 0.85 to 1.0 and 0.49 to 1.0 (readers 1 and 2 respectively), while the inter-observer agreement ranged from 0.41 to 0.79. The intra- and inter-observer intraclass correlation coefficients were excellent and satisfactory, respectively.

CONCLUSION

The scoring system was reliable and may be used for grading bone marrow abnormality in JIA. The relatively large variability in aggregate scores, particularly between readers, underscores the need for thorough standardisation.

MRI appearance of presumed self-inflicted trauma in the knees of military recruits

When knee bone marrow edema is observed on magnetic resonance imaging (MRI), it usually follows a pattern that can be explained by certain etiologies. This article describes a series of unusual knee bone marrow edemas in soldiers presumed to represent self-inflicted trauma.Ten soldiers (9 men and 1 woman; age range, 19-24 years) underwent knee MRI. None reported recent trauma or stress, and all presented with nonspecific pain or failure to respond to therapy. All showed a similar unusual pattern of bone marrow edema in the medial femoral condyle. Three observers evaluated the location of the bone marrow edema within the medial femoral condyle and its distance from the articular surface, dimensions, overlying soft tissue abnormality, and internal derangements. The edema was always subcortical and located in the middle aspect (n=7) or mid-anterior aspect (n=3) of the medial femoral condyle but was never centered subarticularly. Edema size ranged between 8 × 10 × 8 and 32 × 46 × 40 mm. Overlying soft tissue abnormalities were common (n=4) and included organizing (n=1) and residual hematoma (n=3). Concomitant MRI abnormalities were seen in 3 patients, usually minor. Eight patients reported longstanding pain with no antecedent trauma, and 2 reported remote trauma. One patient had a negative 4-month follow-up MRI, and another had a negative arthroscopy. Poor correlation existed between MRI findings and the absence of stress and trauma. Soldier chat rooms were found that describe how to induce fractures at this location.

Bone marrow edema patterns in the ankle and hindfoot: distinguishing MRI features

OBJECTIVE

Many disorders produce similar or overlapping patterns of bone marrow edema in the ankle. Bone marrow edema may present in a few hindfoot bones simultaneously or in a single bone. The purpose of this pictorial essay is to provide guidelines based on clinical history and specific MRI patterns and locations to accurately identify the cause of ankle bone marrow edema. We will first focus on bone marrow edema in general disease categories involving multiple bones, such as reactive processes, trauma, neuroarthropathy, and arthritides. A discussion of bone marrow edema in individual bones of the ankle and hindfoot including the tibia, fibula, talus, and calcaneus will follow. Helpful hints for arriving at the correct diagnosis will be provided in each section.

CONCLUSION

After review of this article, radiologists should be able to use their knowledge of clinical history and specific MRI patterns and locations to accurately distinguish between the various causes of bone marrow edema in the ankle and hindfoot.

Pediatric cervical spine marrow T2 hyperintensity: a systematic analysis

OBJECTIVE

Hyperintense areas of vertebral bone marrow on fluid-sensitive sequences are at times seen on pediatric MRI of the cervical spine in children without suspicious clinical conditions to explain marrow pathology. Although these likely have no clinical significance they may be mistaken for pathology. The purpose of this study is to systematically evaluate the locations and patterns of marrow T2 hyperintensity in the pediatric cervical spine, with respect to age.

MATERIALS AND METHODS

At 1.5 T, the C2 through T3 vertebrae of 82 children aged 0-17 years without clinically suspicious marrow abnormality were retrospectively reviewed by two musculoskeletal radiologists, who were blinded to patients' age. The frequency, intensity, and location of the foci of marrow T2 hyperintensity were recorded for each vertebra on a 12-point scoring system and were correlated with the patients' age.

RESULTS

Foci of marrow hyperintensity were seen in 46/82 (56.1%) patients and in 241/734 (32.8%) vertebrae. Foci were most common in C4 (42% of patients), C5 (45.7%), and C6 (37.8%). The foci of T2 hyperintensity were more common inferiorly (188 foci) and adjacent to the anterior cortex (123). Analysis revealed no significant correlation between age and marrow score (Spearman = -0.147, P = 0.19), but did find a trend towards increased presence of marrow T2 hyperintensity in the ages of most rapid growth, 8-14 years (81.5% of patients).

CONCLUSION

Vertebral body marrow T2 hyperintensity was most common endosteally and in the mid-cervical spine with a slight peak in adolescence. We therefore believe that these pediatric cervical marrow changes may be related to rapid bone growth at the point of maximal kyphotic stress.

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.

Age dependent T2 changes of bone marrow in pediatric wrist MRI

OBJECTIVE

Hyperintensity of the bone marrow on fluid-sensitive sequences can be seen on magnetic resonance imaging (MRI) during childhood, even in the absence of bone pathology. They can be related to hematopoietic marrow, normal and abnormal bone remodeling. We sought to investigate whether hyper intensity of the bone marrow on MRI of the wrist is age-dependent and to evaluate if this signal follows a consistent age-related pattern.

MATERIALS AND METHODS

Thirty-one wrist 1.5 T MR images of children (7-18 years) without suspected bone pathology were evaluated for foci of hyperintense bone marrow seen on fluid-sensitive coronal sequences using a scale of 1-3. Correlation of frequency, location and intensity of these foci with age was obtained. Results were analyzed for distribution in single bones and in the following regions: distal forearm, first/second carpal rows, and metacarpal bases.

RESULTS

A total of 448 bones were evaluated. Eighty-eight out of 448 (21 out of 31 wrists) showed hyperintense bone marrow seen on fluid-sensitive sequences. The distribution was: radius in 19, ulna in 19, first metacarpal base in 11, scaphoid in 9, lunate in 6, pisiform in 6, and fifth metacarpal base in 1. The involvement of the first and second carpal rows and the metacarpal bases was almost similar (13, 12, and 12 respectively). In the distal forearm, the intensity was similar to or higher than that in the wrist (2.2 vs. 2.0). Frequency decreased with age (100% at 7-9 and 25% at 16-18 years).

CONCLUSION

Foci of hyperintense bone marrow seen on fluid-sensitive sequences can be seen on MRI of the wrist during childhood even without apparent symptoms. It shows a consistent pattern with maturation: frequency and intensity decrease and there is distal-to-proximal resolution. This may be a normal finding that may represent normal bone remodeling or decreasing hematopoietic marrow and should not be confused with pathological bone marrow edema.

MR imaging insights into skeletal maturation: what is normal?

Skeletal growth and maturation in children is a dynamic process that can be documented with magnetic resonance (MR) imaging. There are predictable normal developmental changes that must be differentiated from pathologic processes. This review discusses the histologic structure and MR imaging appearance of normal development-related changes of the musculoskeletal system in children, including those that may be mistaken for abnormalities.

Founder's lecture of the ISS 2006: borderlands of normal and early pathological findings in MRI of the foot and ankle

The purpose of this article is to highlight the anatomical variants, technical pitfalls, and the prevalence of abnormal conditions in the asymptomatic population in magnetic resonance imaging of the foot and ankle. Special attention is drawn to the complex anatomy of the deltoid ligament (the superficial tibionavicular ligament, tibiospring ligament, the tibiocalcaneal ligament, and the deep anterior and posterior tibiotalar ligaments) and the posterior tibial tendon insertion including the magic angle artifact and the high prevalence of asymptomatic findings such as "hypertrophied" peroneal tubercle (abnormal only when larger than 5 mm), peroneus quartus (prevalence 17%), and cysts (vascular remnants) just inferior to the angle of Gissane.

Whole-body MRI in children: current status and future applications

Whole-body MRI (WBMRI) is a novel technique that makes imaging of the whole patient in a manner similar to scintigraphy or positron emission tomography (PET) possible. Unlike the latter two methods, it is without exposure to radiation and thus gaining increasing importance and application in pediatrics. With the introduction of a moving tabletop, sequential movement of the patient through the magnet has become possible with automatic direct realignment of the images after acquisition. The common scan plane is coronal with additional planes being added depending on the indication. WBMRI is targeted for maximum coverage of the body within the shortest possible time using the minimum number of sequences. The evaluation of the bone marrow has been the primary indication thus inversion recovery sequences like STIR or TIRM are mostly used with the T1-weighted sequence being added variably. For correct evaluation of the bone marrow in the pediatric age group understanding normal pattern of marrow transformation is essential. The primary role of WBMRI has been in oncology for the detection of tumor spread and also for the follow-up and evaluation of complications. The initial comparative studies of WBMRI with scintigraphy and PET in children have shown the high diagnostic potential of WBMRI. Emerging potential applications of WBMRI include the evaluation for osteonecrosis, chronic multifocal recurrent osteomyelitis, myopathies, and generalized vascular malformations. Future use of WBMRI may incorporate non-accidental trauma, virtual autopsy, body fat mapping and diffusion-weighted imaging.

Review for the generalist: evaluation of pediatric foot and ankle pain

Foot and ankle pain is common in children and adolescents. Problems are usually related to skeletal maturity and are fairly specific to the age of the child. Evaluation and management is challenging and requires a thorough history and physical exam, and understanding of the pediatric skeleton. This article will review common causes of foot and ankle pain in the pediatric population.

[Tumors of the foot skeleton]

About 3-4% of all tumors and tumor-like lesions of the skeleton are located in the foot. Many of these lesions have a predilection for certain locations, so that the spectrum of entities occurring in the foot differs from the rest of the skeleton. Despite the fact that practically any entity can occur in the foot in rare cases, taken together the ten most frequent lesions make up for the vast majority of tumors and tumor-like lesions of the foot. The differential diagnosis of these lesions follows the general principles that apply in the rest of the skeleton. It is based on the analysis of the lesion's X-ray morphology and location, the patient's age, and in certain entities, the MR morphology. This article describes the most important tumors and tumor-like lesions of the foot, their differential diagnosis, and the principles of local staging.

Bone marrow changes on STIR MR images of asymptomatic feet and ankles

The purpose of this study was to evaluate the prevalence, pattern and size of bone marrow changes on short-tau inversion recovery (STIR) magnetic resonance (MR) images of asymptomatic feet and ankles. In 78 asymptomatic volunteers (41 women, 37 men; median age 47 years; range 23-83 years) sagittal STIR MR images of hindfoot and midfoot were reviewed for various patterns of high signal changes in bone marrow. The size of these bone marrow changes was measured, and signal intensity was rated semi-quantitatively using a scale from 0 (=normal) to 10 (=fluid-like). Fifty percent (39/78) of all volunteers had at least one bone marrow change. Thirty-six percent (28/78) of all volunteers had edema-like changes, 26% (20/78) had necrosis-like changes, and 5% (4/78) had cyst-like changes. The long diameters of all changes varied between 4 mm and 16 mm (median 7.5 mm). The median signal intensity for all changes was 5.0 (range 1-10). Bone marrow changes on STIR MR images are commonly detected in asymptomatic feet and ankles. However, such changes tend to be small (<1 cm) or subtle.