Whole-Body Diffusion-Weighted Imaging in Chronic Recurrent Multifocal Osteomyelitis in Children

Challenges in the imaging and diagnosis of chronic non-bacterial osteomyelitis (CNO)

Chronic non-bacterial osteomyelitis (CNO) is a benign skeletal disorder of childhood and adolescence characterised by sterile bone inflammation that results in chronic insidious bone pain. Although it is increasingly recognised, many challenges remain in its diagnosis with patients waiting 15-24 months for diagnosis from the time of symptom onset. Prompt identification and treatment are key to reducing morbidity from CNO, which affects school attendance and can result in chronic limb or spine deformities. Identifying its imaging features, particularly its characteristic lesion distribution on whole-body MRI, remains key to diagnosis. Image-guided biopsy is also required in many cases, particularly those with clinical uncertainty around the diagnosis. We present a review of the challenges encountered in the diagnosis of CNO from a critical appraisal of the literature and our experience as a national paediatric sarcoma, rheumatology and orthopaedic centre. This review hopes to inform radiology colleagues involved in the evaluation of potential CNO patients by discussing its imaging appearances, typical MRI phenotypes, potential mimics and the role of image-guided biopsy.

Chronic Non-Bacterial Osteomyelitis (CNO) in a Tertiary Center in Southern Italy: Response to Treatment and Outcome Stratification

Background/Objectives: Chronic non-bacterial osteomyelitis (CNO) is a rare autoinflammatory disease characterized by chronic sterile uni- or multifocal osteomyelitis. The treatment of CNO is mostly empirical and the outcome of the disease has not yet been standardized. The aims of this study were to correlate clinically active lesions with radiological signs of inflammation and to evaluate the outcomes in terms of symptoms and radiological signs with Whole Body Magnetic Resonance Imaging (WB-MRI) based on the treatment line used. Methods: A retrospective, observational cohort study of 20 CNO patients, recruited from a single tertiary center in southern Italy, was conducted. Patients included in the study were treated based on the "step-up" approach and were guided by the "treat-to-target" strategy as well as by the response to therapy. The outcome measure was stratified into four different groups, defined by a "Delphy consensus", depending on the symptoms and the presence of bone lesions in WB-MRI, compared with the therapy carried out. Results: Pain was the most common presenting symptom of the disease. Only 15% of our patients reported long-term complications. WB-MRI was performed for each patient both at diagnosis and during follow-up. At onset, the site most affected by the disease was the tibia. All patients who reached a 5-year follow-up (30%, n = 6) achieved a complete disease remission. Conclusions: The standardized "step-up" treatment approach in our cohort proved effective in disease management with disease control or remission in nearly 90% of patients at one year from diagnosis.

Quantitative and longitudinal assessment of human placental inflammation using diffusion basis spectrum imaging

Besides exchanging nutrients, gases, and wastes, placenta is an intermediary between maternal and fetal immune systems. However, no method exists to safely image and monitor placental inflammation during pregnancy. We customized a Magnetic Resonance Imaging (MRI) method, diffusion basis spectrum imaging (DBSI), to measure immune cells in placenta. We validated placental DBSI in simulations and ex-vivo specimens, then applied it to 202 MRI scans from 82 patients whose placentas were classified as non-inflammation (n = 70) or inflammation (n = 12). Our method imaged the 3D distribution of immune cells, revealing significantly greater infiltration in the inflammation placentas from early (2.8% ± 0.7% vs. 4.8% ± 0.65%, p < 0.01) to late pregnancy (4.75% ± 0.9% vs. 7.25% ± 2.13%, p < 0.01). DBSI detects elevated immune cell infiltration associated with placental inflammation and enables non-invasive imaging of placental inflammation, offering early detection and monitoring throughout pregnancy, facilitating personalized care and potentially improving pregnancy outcomes without ionizing radiation.

Chronic Noninfectious Osteomyelitis: A Review of Imaging Findings

Chronic noninfectious osteomyelitis or chronic nonbacterial osteomyelitis (CNO), also known as chronic recurrent multifocal osteomyelitis, is an autoinflammatory bone disorder primarily affecting the pediatric age group. Currently, it is diagnosed on the basis of clinical, laboratory, and imaging features. Imaging plays a crucial role in the diagnosis and follow-up of CNO with whole body magnetic resonance imaging (WBMRI) being the main modality. Radiographs assist in exclusion of common differential diagnoses like infections and malignancy. WBMRI aids in disease detection and exclusion of differential diagnoses, identifies additional lesions, and has a role in ascertaining the pattern of bony involvement which helps with prognostication and grading. Recent recognition of specific morphological and distribution patterns on WBMRI is increasingly allowing an upfront diagnosis of this entity to be made on imaging alone. It is also helpful for assessment of response to therapy during follow-up. This review aims to summarize the role of imaging in the evaluation of CNO, with special emphasis on WBMRI in its assessment.

Spine Involvement and Vertebral Deformity in Patients Diagnosed with Chronic Recurrent Multifocal Osteomyelitis

BACKGROUND

Chronic recurrent multifocal osteomyelitis (CRMO) is an inflammatory disorder of bone, typically arising adjacent to the physes of long bones but also seen throughout the skeleton. For patients with spinal involvement, CRMO lesions can cause compression deformities with a range of severity from minimal anterior wedging to circumferential height loss, known as vertebra plana. This study examines a large cohort of CRMO patients to determine the prevalence of spine involvement and vertebral deformity.

METHODS

This is a retrospective review of all patients with a diagnosis of CRMO seen at our institution between January 2003 and December 2020. These patients were identified through a prospectively maintained database of all CRMO patients seen at the institution. A retrospective review was undertaken to identify all patients with spinal involvement and determine the prevalence of CRMO in the spine and its effects on vertebral height and deformity.

RESULTS

Of 170 patients included in this study, 48 (28.2%) were found to have spinal involvement. Among patients with spinal involvement, vertebral body lesions were identified in 27 (56.3%) patients. The remaining lesions were in the sacrum or posterior elements. Radiographic evidence of the vertebral body height loss was noted in 23 of these 27 patients.

CONCLUSIONS

This cohort of CRMO patients demonstrates that 28% of patients have spinal involvement, and 48% of those patients have vertebral body height loss. While the ideal treatment for spinal CRMO has yet to be determined, imaging studies, including whole-body MRI and spine-specific MRI, are useful in identifying vertebral lesions and deformities. Identification and surveillance of these lesions are important as the disorder has a relapsing and remitting course, and patients can develop significant vertebral body height loss. Once deformity has developed, we have seen no evidence of reconstitution of the height of the collapsed vertebra. Bisphosphonates have been successful in preventing the progression of vertebral body height loss.

LEVEL OF EVIDENCE

Level II: Retrospective study investigating spinal involvement and prevalence of vertebral body deformity in patients diagnosed with CRMO.

Bone marrow edema in children: chronic nonbacterial osteomyelitis and its mimickers

Bone marrow is a highly cellular tissue undergoing significant developmental and physiologic changes with age. Indeed, with maturation from pediatric to the adult age there is a progressive, centrifugal conversion from red to yellow bone marrow. Histological characteristics of bone marrow are reflected in MR image signal. MR is therefore extremely sensitive in detecting pathological changes which are mostly characterized by increased free water causing high signal intensity on T2. Among the numerous diseases causing bone marrow edema in children chronic nonbacterial osteomyelitis (CNO) certainly has to be mentioned. This idiopathic inflammatory disorder is characterized by nonspecific migrating symptoms like skeletal pain with phases of exacerbations and relapses with alternating acute and chronic MR signs and it is often a diagnosis of exclusion. Hence, with bone marrow edema, various features at imaging should be considered to differentiate malignancies such as osseous lymphoma, osteosarcoma, and Ewing's sarcoma as well as benign lesions like osteomyelitis, post-traumatic, or post-treatment bone marrow edema. The aim of this review is to recall the main characteristics of CNO and provide an overview of its main mimickers highlighting similarities and differences.

Chronic non-bacterial osteomyelitis (CNO) and chronic recurrent multifocal osteomyelitis (CRMO) with a focus on pamidronate therapy

Chronic recurrent multifocal osteomyelitis (CRMO), also called chronic nonbacterial osteomyelitis (CNO) or nonbacterial osteomyelitis (NBO), is a rare autoinflammatory bone disease of unknown etiology. However, the number of patients properly diagnosed would increase with better knowledge of the disease. In this regard, whole-body magnetic resonance imaging (WB MRI) has been found to be a better predictor of active lesions than clinical examination. Importantly, the RINBO index (radiologic index for NBO) quantifies the involvement based on the WB MRI. Further, a chronic nonbacterial osteomyelitis MRI scoring (CROMRIS) has been developed as an online tool for assessing WB MRI. The therapy consists of non-steroidal anti-inflammatory drugs (NSAIDs), bisphosphonates (pamidronate, zoledronate, etc.) and other drugs, including biologics. Pamidronate is an appropriate and safe therapy. The first pilot prospective randomised controlled trial (RCT) on pamidronate vs. placebo was carried out in adults. No RCT has been done in children yet. Besides RCTs, there are a number of issues to be explored in future, i.e. predictors of therapy effect, optimal therapy duration, predictors of therapy discontinuation and evaluation of optimal therapy protocol. Recently, the CNO clinical disease activity score (CDAS) was constructed and validated but the classification criteria are still being developed. As collaboration on this rare disease is essential, a prospective Chronic Nonbacterial Osteomyelitis International Registry (CHOIR) was established to generate future comparative effectiveness research data.

Treatment Effect of Zoledronic Acid in Chronic Non-bacterial Osteomyelitis of the Jaw: A Case Series

Chronic non-bacterial osteomyelitis (CNO) is an autoinflammatory, osteolytic bone disorder sometimes localized to a unifocal site in the jaw, causing long-term pain and reduced function. The aim of this study was to describe the patients with CNO of the jaw, focusing on treatment with zoledronic acid for pain relief. An analysis of medical records of 24 patients with CNO of the jaw, including treatment with zoledronic acid and effects on pain relief. Descriptive statistics and nonparametric tests were used to describe the population and compare treatment effects, respectively. The average treatment period was 33.4 months (median 23; Q1 11.5; Q3 42.0) with an average of 4.1 infusions (median 3; Q1 2; Q3 5) of zoledronic acid. The average pain VAS score (visual analogue scale) was significantly reduced from 7.7 (median 8; Q1 6.5; Q3 8.5) to 2.5 points (median 2; Q1 0.5; Q3 4.5) (p < 0.001). At final visit, 46% of patients reported no pain and 38% reported a reduction of pain. At least 67% of patients had at least one episode of pain recurrence, and most patients experienced the first recurrence within a year of initial treatment. Four patients (16%) had no pain relief from the treatment. In this group of patients with CNO of the jaw, there was a positive response to treatment with zoledronic acid on pain relief, averaging 5.2 points on a pain VAS score, with 84% of patients treated experiencing either a partial or a total reduction in pain after about 2.5 years.

State of the art in the diagnostic evaluation of osteomyelitis: exploring the role of advanced MRI sequences-a narrative review

Background and Objective

Osteomyelitis, a severe bone infection caused mainly by pyogenic organisms, poses diagnostic challenges due to its non-specific magnetic resonance imaging (MRI) manifestations. Conventional MRI, though the imaging modality of choice, often exhibits signal abnormalities with overlapping differential diagnoses, potentially leading to overestimation of infection extent and duration. To address these limitations, advanced MRI sequences, including dynamic contrast-enhanced (DCE) MRI, 1H magnetic resonance spectroscopy (MRS), diffusion-weighted imaging (DWI), and Dixon techniques have emerged as promising alternatives. This narrative review explores the potential role of these sequences in aiding the differential diagnosis of osteomyelitis.

Methods

We used the PubMed database to search for relevant articles using the MeSH keywords: (osteomyelitis) AND (advanced MRI sequences) and we manually selected the most suitable studies to include in our review. Articles outside of original studies were also included. Only records in English or French were considered.

Key Content and Findings

In particular, DWI is useful for characterizing fluid collections, distinguishing bone infarcts, and bacterial skull base osteomyelitis from neoplastic lesions. Moreover, DWI assists in differentiating diabetic foot osteomyelitis (DFO) from Charcot neuro-osteoarthropathy, facilitates the diagnosis of pediatric acute osteoarticular infections, and aids in distinguishing osteomyelitis from Modic I degenerative changes. Additionally, DWI proves valuable in monitoring spinal infections and distinguishing pedal osteomyelitis from other conditions, even in patients with renal impairment. DCE-MRI enhances MRI specificity by assessing contrast uptake over time, providing valuable insights into inflammatory microenvironments. It aids in detecting DFO, differentiating it from acute Charcot arthropathy, and distinguishing osteomyelitis from neuropathic arthropathy. Moreover, DCE-MRI shows potential in assessing response to antibiotic therapy in spinal infections. Dixon acquisition improves image quality and facilitates the detection of bone marrow abnormalities, aiding in the differentiation of diabetic foot from osteomyelitis. It also assists in distinguishing osteomyelitis from neuropathic arthropathy and provides valuable information in evaluating the diabetic foot. Proton MR spectroscopy, a well-established modality, offers metabolic information that can differentiate malignant from benign lesions.

Conclusions

The role of advanced MRI techniques in evaluating osteomyelitis remains to be fully defined, and further research is required to explore its potential utility in this context. In conclusion, the incorporation of advanced MRI sequences has shown promise in improving the differential diagnosis of osteomyelitis. Future investigations exploring combinations of these techniques and their clinical applications hold significant potential to enhance diagnostic accuracy and patient outcomes.

[Primary chronic osteomyelitis of the mandible in children: etiology and diagnostics]

Primary chronic osteomyelitis (PCO) is a rare non-bacterial autoinflammatory severe disease that most often affects children aged 7 to 12 years and is much less common in adults. The most common areas of lesion are long tubular bones, however, any bones of the skeleton, including the lower jaw, can be affected. The clinical picture of this disease is complex and similar to many tumor and tumor-like bone lesions, which often leads to a significant delay in making a correct diagnosis. The diagnosis of primary chronic osteomyelitis is primarily based on the exclusion of other diseases by comparing the data of radiation diagnosis, clinical course and histological examination of biopsy material. In this article, which is part 1 of a two-part series, the authors review the clinical presentation of PCO, its suggested causes found in the literature, and current diagnostic methods.

Non-neoplastic pathologies mimicking sarcoma - Experience from a tertiary referral centre multidisciplinary team

OBJECTIVE

Distinguishing non-neoplastic tumour-mimicking pathologies from bone and soft tissue tumours is one of the fundamental aims of a tertiary centre sarcoma multidisciplinary team (MDT) service. In this study, we aim to analyse the incidence of non-neoplastic lesions referred to a tertiary referral service as suspected sarcoma, and to analyse the spectrum of conditions comprising these tumour-mimicking pathologies.

MATERIALS AND METHODS

We conducted a retrospective observational study compiling the biopsy-proven non-neoplastic outcomes of suspected sarcoma cases referred to our MDT in the last year. We identified all referrals made to our service between 1st January 2020 and 31st December 2020 and compiled their histological diagnoses.

RESULTS

A total of 976 new cases were referred to our MDT as suspected sarcoma in one year. Of these referrals, 8.6% (84/976) received a biopsy-proven outcome of non-neoplastic pathology. These non-neoplastic outcomes were categorised into the following types of pathology: 32.1% vascular, 31.0% inflammatory, 14.3% traumatic, 6.0% degenerative, 6.0% idiopathic, 4.8% infective, 3.6% metabolic, 1.2% autoimmune, and 1.2% genetic.

CONCLUSION

A significant proportion of pathologies referred to a tertiary centre sarcoma MDT are non-neoplastic in nature. These lesions are made up of a range of pathologies, with vascular and inflammatory conditions being the most common. Our study, the first of its kind, offers clinicians an insight into tumour-mimicking pathologies encountered by a tertiary centre.

Whole-body MRI in children: state of the art

Whole-body magnetic resonance imaging (WBMRI) is an increasingly popular technique in paediatric imaging. It provides high-resolution anatomical information, with the potential for further exciting developments in acquisition of functional data with advanced MR sequences and hybrid imaging with radionuclide tracers. WBMRI demonstrates the extent of disease in a range of multisystem conditions and, in some cases, disease burden prior to the onset of clinical features. The current applications of WBMRI in children are hereby reviewed, along with suggested anatomical stations and sequence protocols for acquisition.

Whole body magnetic resonance imaging in healthy children and adolescents. Bone marrow appearances of the axial skeleton

OBJECTIVE

To describe the findings of focal high signal on T2 weighted (T2W) images of the bone marrow in the axial skeleton as assessed by whole-body MRI in healthy and asymptomatic children and adolescents.

MATERIAL AND METHODS

We assessed the bone marrow of the mandible, shoulder girdle, thorax, spine, and pelvis on water-only Dixon T2W sequences as part of a whole-body MRI protocol in 196 healthy and asymptomatic children aged 5-19 years. Intensity (0-2 scale) and extension (1-4 scale) of focal high signal areas in the bone marrow were scored and divided into minor or major findings, based on intensity and extension to identify the potentially conspicuous lesions in a clinical setting.

RESULTS

We registered 415 areas of increased signal in the axial skeleton whereof 75 (38.3%) were major findings. Fifty-eight (29.6%) individuals had at least one major finding, mainly located in the pelvis (54, 72%). We found no differences according to gender. The number of minor findings increased with age (p = 0.020), but there were no significant differences in the number of major findings. The most conspicuous findings were in the pelvis, spine and sternum.

CONCLUSION

Non-specific bone marrow T2W hyperintensities in the axial skeleton are frequently detected on whole-body MRI in healthy, asymptomatic children. Awareness of this is important as some findings may resemble clinically silent lesions in children with suspected multifocal skeletal disease.

Chronic nonbacterial osteomyelitis in children: a multicentre Belgian cohort of 30 children

BACKGROUND

To evaluate clinical characteristics, imaging findings, therapeutic approach and outcome of paediatric patients with Chronic Non-Bacterial Osteomyelitis (CNO).

METHODS

Retrospective review of 30 children diagnosed with CNO at two tertiary care centres in Belgium. Imaging data were evaluated by blinded paediatric radiologists.

RESULTS

Mean age at onset was 10.3 years and mean age at diagnosis was 11.7 years. Bone pain was the leading symptom (29/30 patients). Out of 180 symptomatic lesions, 131 were confirmed on MRI as hyperintense geographic lesions on STIR images at the metaphysis and epiphysis adjacent to growth plates of tubular bones. The most common sites of involvement were the lower limbs, spine, sternoclavicular joint and humerus. For nearly half of the patients (14/30) monotherapy with NSAIDs was sufficient to obtain remission. The remaining 16 patients received second-line therapy: bisphosphonates (n = 15/30), disease-modifying antirheumatic drugs (n = 7/30), etanercept (n = 4/30) and tocilizumab (n = 1/30). Remission was reached after a mean time of 37.6 months in 26/30 patients. The prognosis was worse for patients with spinal involvement, resulting in more long-term sequelae.

CONCLUSIONS

We present a multicentre paediatric cohort of 30 CNO patients. A typical pattern of bone involvement could be found on MRI. NSAIDs were administered as first-line treatment. Second-line strategies included bisphosphonates, corticosteroids, methotrexate, etanercept and tocilizumab.

TRIAL REGISTRATION

Retrospectively registered. Registratienummer EC KUL: MP018023.

Whole-body magnetic resonance imaging findings and patterns of chronic nonbacterial osteomyelitis in a series of Greek pediatric patients

Background:

Chronic nonbacterial osteomyelitis (CNO) is a pediatric autoinflammatory disorder presenting with sterile inflammatory bone lesions. Whole-body MRI (WBMRI) has most recently emerged for disease assessment, but data are limited.

Purpose:

The purpose is to evaluate the imaging findings and patterns of CNO on WBMRI in a series of Greek pediatric patients.

Material and Methods:

Whole-body magnetic resonance imaging studies of all children with documented CNO, performed in a single tertiary center, were retrospectively reviewed. WBMRI included coronal T1 and short-tau inversion recovery (STIR), whole spine sagittal STIR, and ankle/foot sagittal STIR images. High signal intensity lesions on STIR images corresponding to bone marrow edema were recorded. The SPSS v.20 statistical package was used for descriptive statistics.

Results:

Twenty children were included (mean age: 12, range: 6–16 years) with 1–31 lesions (mean: 11.8) on WBMRI. Two children had unifocal disease localized at the clavicle, three paucifocal (1–4 lesions), and 15 multifocal bone involvement. All but two children presented with ankle pain and exhibited lesions at the bones of the ankle joint (90%) followed by the knee (50%) and pelvis (10%). The tibia was the most frequently affected bone (70%) followed by calcaneus (60%), fibula (50%), femur (45%), talus, and metatarsals (45%). No lesions in the cervical, thoracic, lumbar spine, and mandible were documented. Only small sacral lesions were seen in 25% of patients with the extensive peripheral disease. Bilateral metaphyseal and epiphyseal involvement with transphyseal extension were common, but the periosteal reaction and well-defined lesion margins were rare.

Conclusion:

Frequent involvement of the foot and ankle and paucity of substantial spinal involvement were seen in Greek pediatric patients with CNO.

Benefits of diffusion-weighted imaging in pediatric acute osteoarticular infections

BACKGROUND

Contrast-enhanced magnetic resonance imaging (MRI) is recommended for the diagnosis of acute osteoarticular infections in children. Diffusion-weighted imaging (DWI) may be an alternative to the injection of gadolinium.

OBJECTIVE

To evaluate unenhanced MRI with DWI in comparison to contrast-enhanced MRI for the diagnostic work-up of acute osteoarticular infections in children.

MATERIALS AND METHODS

This retrospective study included 36 children (age range: 7 months-12 years) with extra-spinal osteoarticular infections and MRI performed within 24 h of admission. MRI protocol included short tau inversion recovery (STIR), water-only T2 Dixon, T1, DWI, and gadolinium-enhanced T1 sequences. Two readers reviewed three sets of images: 1) unenhanced sequences, 2) unenhanced sequences with DWI and 3) unenhanced followed by contrast-enhanced sequences (reference standard). Sensitivity and specificity of sets 1 and 2 were compared to set 3 and assessed to identify osteoarticular infections: osteomyelitis (long bones, metaphyseal equivalents), septic arthritis and abscess (soft tissues, bone).

RESULTS

All 14 cases of osteomyelitis in the metaphyses and diaphyses of long bones and all 27 cases of septic arthritis were identified by unenhanced sequences, but 4/16 abscesses were missed. For the diagnosis of abscess, DWI increased sensitivity to 100%. Among the 18 osteomyelitis in metaphyseal equivalents, 4 femoral head chondroepiphyses were identified by contrast-enhanced sequences only.

CONCLUSION

MRI for suspected pediatric acute osteoarticular infections is the best diagnostic modality to guide patient management. An unenhanced protocol with DWI may be an alternative to a contrast-based protocol, even in the presence of an abscess. However, gadolinium remains necessary to assess for chondroepiphyseal involvement of the femoral head.

MRI in the Diagnosis and Treatment Response Assessment of Chronic Nonbacterial Osteomyelitis in Children and Adolescents

PURPOSE OF REVIEW

To explain the central role of magnetic resonance imaging (MRI) in the diagnosis and follow-up of chronic nonbacterial osteomyelitis (CNO) in children and adolescents, centering on practical technical aspects and salient diagnostic features.

RECENT FINDINGS

In the absence of conclusive clinical features and widely accepted laboratory tests, including validated disease biomarkers, MRI (whether targeted or covering the entire body) currently plays an indispensable role in the diagnosis and therapy response assessment of CNO. Whole-body MRI, which is the reference imaging standard for CNO, can be limited to a short tau inversion recovery (STIR) coronal image set covering the entire body and a STIR sagittal set covering the spine, an approximately 30-min examination with no need for intravenous contrast or diffusion-weighted imaging. The hallmark of CNO is periphyseal (metaphyseal and/or epi-/apophyseal) osteitis, identified as bright foci on STIR, with or without inflammation of the adjacent periosteum and surrounding soft tissue. Response to bisphosphonate treatment for CNO has some unique MRI findings that should not be mistaken for residual or relapsing disease. Diagnostic features and treatment response characteristics of MRI in pediatric CNO are discussed, also describing the techniques used, pitfalls encountered, and differential diagnostic possibilities considered during daily practice.

Whole-body MRI in pediatric undefined inflammatory conditions

BACKGROUND

Whole-body magnetic resonance imaging (WBMRI) is a multiregional imaging technique suitable for investigating the extent of multisystemic diseases without exposure to radiation, with a high sensitivity to bone alterations. The aim of our study was to evaluate the role of WBMRI in the workup of children with non-specific musculoskeletal features and non-indicative laboratory and instrumental data, who were suspected to have a rheumatologic disease.

METHODS

We retrospectively analyzed medical records, including laboratory tests and radiological data of 34 children who had been evaluated due to non-specific musculoskeletal manifestations, for which a WBMRI was prescribed.

RESULTS

We included 34 children, 19 females and 15 males, mean age 10 years (range 2-16 years), with the following clinical features: diffuse arthralgia (12 children), persistent fever (2 children), persistent fever and diffuse arthralgia (20 children). Serologic inflammatory markers were increased in 29/34 patients. Twenty-five children had already received X-ray and / or ultrasound before WBMRI, with a negative / uninformative result. WBMRI was performed 3-6 weeks (median, 3.5 weeks) after the initial presentation of symptoms. In 22/34 (65%) children, WBMRI revealed some abnormalities that supported the final diagnosis. Twelve out of 34 children (35%) were be affected by chronic recurrent multifocal osteomyelitis.

CONCLUSIONS

WBMRI is helpful in pediatric rheumatology for the differential diagnosis of undefined inflammatory conditions. It appears to be a promising tool, especially in the detection of multifocal bone lesions. The diagnosis that mainly benefits from WBMRI in our series is chronic recurrent multifocal osteomyelitis. WBMRI can also help in excluding neoplastic diseases.

Review of spinal involvement in Chronic recurrent multifocal osteomyelitis (CRMO): What radiologists need to know about CRMO and its imitators

Chronic recurrent multifocal osteomyelitis (CRMO) is a distinct disease entity of unknown etiology primarily affecting children and adolescents. It is an autoinflammatory process that typically affects multiple bones with a waxing and waning course. About one third of the patients diagnosed with CRMO have spinal involvement which can lead to long term morbidity. The clinical presentation and imaging features of CRMO involving the spine are nonspecific and can mimic other disease processes like infection or malignancy. Since imaging plays a very important role in the diagnosis and management of CRMO, we intend to highlight various imaging patterns of spinal CRMO alongside its clinical features and briefly discuss its imitators, management and outcomes.

Chronic Nonbacterial Osteomyelitis: Insights into Pathogenesis, Assessment, and Treatment

Chronic nonbacterial osteomyelitis, or its most severe form, chronic recurrent multifocal osteomyelitis, is an autoinflammatory bone disease that causes skeletal inflammation characterized by bone pain and swelling that primarily affects children. It is a diagnosis of exclusion and its clinical presentation may mimic underlying infectious processes and malignancy. Clinical suspicion for this diagnosis and timely referral to pediatric rheumatology is crucial to achieve earlier diagnosis, appropriate treatment, and improved quality of life of affected patients and families. This article focuses on recent insights into the pathogenesis of chronic nonbacterial osteomyelitis and outlines recent advances and ongoing research.

Diffusion-weighted MR imaging in chronic non-bacterial osteitis: Proof-of-concept of the apparent diffusion coefficient as an outcome measure

Background

The apparent diffusion coefficient (ADC), as determined by whole-body diffusion-weighted MRI, may be useful as an outcome measure for monitoring response to treatment in chronic non-bacterial osteitis.

Purpose

To test and demonstrate the feasibility of ADC-measurement methods for use as outcome measure in chronic non-bacterial osteitis.

Materials and Methods

Using data from a randomized pilot study, feasibility of change-score ADC between baseline and second MRI (ΔADC₁₂) and third MRI (ΔADC₁₃) as outcome measure was assessed in three settings: “whole-lesion,” “single-slice per lesion,” and “index-lesion per patient”. Bone marrow edema lesions were depicted on short tau inversion recovery sequence at baseline and copied to ADC maps at the three time-points. Correlations between the three settings were measured as were analysis of variances. Discriminant validity was assessed as inter- and intra-observer reproducibility and smallest detectable change.

Results

12 subjects were enrolled, and MRI was performed at baseline and weeks 12 and 36. Pearson correlation was high (r > 0.86; p ≤ 0.01) for ΔADC between single-slice—whole-lesion and whole-lesion—index-lesion and tended to be significant for single-slice—index-lesion settings (p = 0.06). For ΔADC₁₂ and ΔADC₁₃, Bland–Altman plots showed small differences (0.02, 0.03) and narrow 95% limits-of-agreement (−0.13–0.09, −0.07–0.05 μm²/s) between whole-lesion and single-slice ROI settings. Inter-observer reproducibility measured by intra-class correlation coefficient was poor-to-fair (range: 0.09–0.31), whereas intra-observer reproducibility was good-to-excellent (range: 0.67–0.90). Smallest detectable changes were between 0.21–0.28 μm²/s.

Conclusion

ADC change-score as outcome measure was feasible, and the single-slice per lesion ROI setting performed almost equally to whole-lesion setting resulting in reduced assessment time.

Assessment of disease activity using a whole-body MRI derived radiological activity index in chronic nonbacterial osteomyelitis

BACKGROUND

Based on the recently developed ChRonic nonbacterial Osteomyelitis MRI Scoring tool (CROMRIS), we developed a radiological activity index (RAI-CROMRIS) to obtain a quantification of the overall bone involvement in individual patients.

METHODS

Whole Body Magnetic Resonance Imaging (WB-MRI) images were scored according to parameters included in the RAI-CROMRIS: bone marrow hyperintensity, signal extension, soft tissue/periosteal hyperintensity, bony expansion, vertebral collapse. These parameters were evaluated for each bone unit yielding a score from 0 to 7 and summed up as RAI-CROMRIS including all bone units. We assessed clinical disease activity using a physician global assessment (PGA) and radiological findings in 76 treatment-naïve patients; 46 of 76 were evaluated at 6 and 12 months after initial WB-MRI. Quantitative variables were compared using the Mann-Whitney U test for unmatched groups and the Wilcoxon signed-rank test for paired groups. Correlation was evaluated using Spearman's rank coefficient (r_s).

RESULTS

There was a significant correlation between RAI-CROMRIS and PGA (r_s = 0.32; p = 0.0055), between RAI-CROMRIS and presence of elevated erythrocyte sedimentation rate (p = 0.013) and C-reactive protein (p = 0.0001) at baseline. The RAI-CROMRIS decreased from a median of 17 at baseline to 12 at 6 months (p = 0.004) and remained stable (median 11) at 12 months. A correlation between the RAI-CROMRIS and the PGA was observed at baseline (r_s = 0.41; p = 0.004) and during follow up at 6 months (r_s = 0.33; p = 0.025) and 12 months (r_s = 0.38; p = 0.010). The baseline RAI-CROMRIS (median 20) was significantly higher in patients who subsequently received bisphosphonates than in patients who received other treatments (median 12) and decreased significantly after bisphosphonates (p = 0.008).

CONCLUSIONS

The RAI-CROMRIS was correlated with clinical and laboratory measures of disease activity showing significant short-term changes following treatment with bisphosphonates. This tool could be used in clinical practice and clinical trials after validation.

Imaging in non-bacterial osteomyelitis in children and adolescents: diagnosis, differential diagnosis and follow-up-an educational review based on a literature survey and own clinical experiences

Background

Chronic non-bacterial osteomyelitis (CNO) is an autoinflammatory bone disorder affecting children and adolescents. Previously classified as a rare disease, recent studies suggest a higher incidence of the disease. CNO may develop into the clinical presentation of chronic recurrent osteomyelitis (CRMO) with high relapse rate and multifocality.

Main body

Diagnosis of CNO/CRMO is often delayed, with implications for disease severity and relapse rate. This can be significantly improved by knowledge of the disease entity and its characteristics. Imaging plays a key role in diagnosis, differential diagnosis and therapy monitoring. Magnetic resonance imaging (MRI) has several advantages compared to other imaging methods and is increasingly applied in clinical studies. Recent studies show that a whole-body (WB) coverage (WB-MRI) without contrast agent administration is a rational approach. This educational review is based on a systematic analysis of international peer-reviewed articles and presents our own clinical experiences. It provides an overview of disease entity, incidence and clinical diagnosis. The role of imaging, especially of whole-body MRI, is discussed in detail. Finally, practical advice for imaging, including flowcharts explaining when and how to apply imaging, is provided.

Conclusion

Knowing the specifics of CNO/CRMO and the importance of MRI/whole-body MRI allows rapid and efficient diagnosis as well as therapy support and helps to avoid irreversible secondary damage.

Pediatric skeletal diffusion-weighted magnetic resonance imaging, part 2: current and emerging applications

Diffusion-weighted imaging (DWI) complements the more established T1, fluid-sensitive and gadolinium-enhanced magnetic resonance pulse sequences used to assess several pediatric skeletal pathologies. There is optimism that the technique might not just be complementary but could serve as an alternative to gadolinium and radiopharmaceuticals for several indications. As a non-contrast, free-breathing and noninvasive technique, DWI is especially valuable in children and is readily incorporated into existing MRI protocols. The indications for skeletal DWI in children include distinguishing between benign and malignant skeletal processes, initial assessment and treatment response assessment for osseous sarcomas, and assessment of inflammatory arthropathies and femoral head ischemia, among others. A notable challenge of diffusion MRI is the dynamic nature of the growing pediatric skeleton. It is important to consider the child's age when placing DWI findings in context with potential marrow pathology. This review article summarizes the current and evolving applications of DWI for assessing the pediatric skeleton, rounding off the discussion with evolving directions for further research in this realm.

Pediatric skeletal diffusion-weighted magnetic resonance imaging: part 1 - technical considerations and optimization strategies

Diffusion-weighted MRI, or DWI, is a fast, quantitative technique that is easily integrated into a morphological MR acquisition. The ability of DWI to aid in detecting multifocal skeletal pathology and in characterizing tissue cellularity to a level beyond that possible with other techniques makes it a niche component of multiparametric MR imaging of the skeleton. Besides its role in disease detection and establishing cellularity and character of osseous lesions, DWI continues to be examined as a surrogate biomarker for therapeutic response of several childhood bone tumors. There is increasing interest in harnessing DWI as a potential substitute to alternative modes of imaging evaluation that involve radiation or administration of intravenous contrast agent or radiopharmaceuticals, for example in early detection and diagnosis of capital femoral epiphyseal ischemia in cases of Legg-Calvé-Perthes disease, or diagnosis and staging of lymphoma. The expected evolution of skeletal diffusivity characteristics with maturation and the unique disease processes that affect the pediatric skeleton necessitate a pediatric-specific discussion. In this article, the author examines the developmentally appropriate normal appearances, technique, artifacts and pitfalls of pediatric skeletal DWI.

Chronic Nonbacterial Osteomyelitis in Children

Chronic nonbacterial osteomyelitis (CNO) is an auto-inflammatory bone disorder with a wide spectrum of clinical manifestations, from unifocal to multifocal lesions. When it manifests with multifocal lesions, it is also referred to as chronic recurrent multifocal osteomyelitis (CRMO). CNO/CRMO can affect all age groups, with the pediatric population being the most common. Patients may present with systemic inflammation, but there is no pathognomonic laboratory finding. Magnetic resonance imaging (MRI) is the gold standard radiological tool for diagnosis. In the absence of validated diagnostic criteria, CNO/CRMO remains an exclusion diagnosis. Bone biopsy does not show a specific disease pattern, but it may be necessary in unifocal or atypical cases to differentiate it from malignancy or infection. First-line treatments are non-steroidal anti-inflammatory drugs (NSAIDs), while bisphosphonates or TNF-α blockers can be used in refractory cases. The disease course is unpredictable, and uncontrolled lesions can complicate with bone fractures and deformations, underlying the importance of long-term follow-up in these patients.

Chronic Recurrent Multifocal Osteomyelitis of the Hand: A Rare Pediatric Condition

Background: Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory condition characterized by bone pain and swelling, secondary to sterile bone osteolytic lesions. Estimated incidence is 1:1 000 000, with ~2% involving the hand. We present a case series of CRMO of the hand and review the available literature, with the aim of educating and raising awareness of this condition. Methods: A retrospective chart review was conducted for all patients presenting to the institution diagnosed with CRMO involving the hands. Subsequently, a literature review was performed. Results/Case Series: Three cases of CRMO of the hand were identified. Age ranged from 20 months to 6 years, with 1 female. Time from presentation to diagnosis ranged from 3 to 15 months. Two had a single lesion, with the remaining patient having a second lesion on full-body magnetic resonance imaging (MRI). Three lesions involved phalanges, and one involved a metacarpal. Two received antibiotics without improvement prior to diagnosis. After diagnosis of CRMO, two received intravenous pamidronate. They both later showed improvement on MRI. Conclusion: CRMO is a rare disease with scarce literature to guide management. We present a series of CRMO specifically of the hand. The cases educate key stakeholders, raise awareness of the diagnosis, and illustrate challenging aspects of managing these patients. This includes the special functional and anatomical consideration essential in managing cases involving the hand.

Whole-body MRI in the diagnosis of paediatric CNO/CRMO

Chronic recurrent multifocal osteomyelitis (CRMO) is an auto-inflammatory disorder affecting the skeleton of children and adolescents. Whole-body MRI (WBMRI) is key in the diagnosis and follow-up of CRMO. Imaging protocols should include sagittal short Tau inversion recovery of the spine, imaging of the hands and feet, and T1 images for distinguishing normal bone marrow. CRMO lesions can be metaphyseal, epiphyseal and physeal-potentially causing growth disturbance and deformity. Spinal lesions are common, important and can cause vertebral collapse. Lesion patterns include multifocal tibial and pauci-focal patterns that follow a predictable presentation and course of disease. Common pitfalls of WBMRI include haematopoietic marrow signal, metaphyseal signal early on in bisphosphonate therapy and normal high T2 signal in the hands and feet. Pictorial reporting assists in recording lesions and follow-up over time. The purpose of this paper is to review the different WBMRI protocols, imaging findings, lesion patterns and common pitfalls in children with CRMO.

Whole-body magnetic resonance imaging in inflammatory diseases: Where are we now? Results of an International Survey by the European Society of Musculoskeletal Radiology

PURPOSE

To investigate the current role of WB-MRI for rheumatic inflammatory diseases in clinical practice using a survey addressed to musculoskeletal radiologists.

METHODS

A survey composed of 61 questions, subdivided in three sections, demographics (five questions), application of WB-MRI for inflammatory musculoskeletal diseases in adults and children (28 questions: 7 open and 21 multiple choice for each subgroup) was distributed via the European Society of Musculoskeletal Radiology (ESSR) from July 2 to December 31, 2018 to radiologists working in academic, private, and public workplaces. Comparisons among the different workplaces were performed using the Chi-squared and the Kruskal-Wallis test for nominal and ordinal data, respectively (p < 0.05).

RESULTS

Seventy-two participants out of the 1779 (4%) members of the ESSR with 10.4 ± 7.9 years of experience in musculoskeletal imaging, replied to at least one question. 30.6% and 12.3% of the respondents performed at least 50 WB-MRI examinations per year in adults and children, respectively. The most frequent indications were myositis in adults and chronic recurrent multifocal osteomyelitis (CRMO) in children, the latter mostly in academic centers (p = 0.013). The ESSR Arthrits Subcommitte's protocol was applied by half of the participants and especially radiologists working in private practice used it for adults (p = 0.025). Contrast medium was rarely used for adults particularly by academics (p = 0.04). Diffusion Weighted Imaging was applied for children mostly in private practice (p = 0.01) although, overall, it plays a marginal role. Scoring systems were rarely used. Ongoing research is limited.

CONCLUSION

WB-MRI is not routinely applied for musculoskeletal inflammatory diseases. The most frequent indications are myositis and CRMO.

Whole-body magnetic resonance imaging in children - how and why? A systematic review

Whole-body magnetic resonance imaging (MRI) is increasingly being used for a number of indications. Our aim was to review and describe indications and scan protocols for diagnostic value of whole-body MRI for multifocal disease in children and adolescents, we conducted a systematic search in Medline, Embase and Cochrane for all published papers until November 2018. Relevant subject headings and free text words were used for the following concepts: 1) whole-body, 2) magnetic resonance imaging and 3) child and/or adolescent. Included were papers in English with a relevant study design that reported on the use and/or findings from whole-body MRI examinations in children and adolescents. This review includes 54 of 1,609 papers identified from literature searches. Chronic nonbacterial osteomyelitis, lymphoma and metastasis were the most frequent indications for performing a whole-body MRI. The typical protocol included a coronal STIR (short tau inversion recovery) sequence with or without a coronal T1-weighted sequence. Numerous studies lacked sufficient data for calculating images resolution and only a few studies reported the acquired voxel volume, making it impossible for others to reproduce the protocol/images. Only a minority of the included papers assessed reliability tests and none of the studies documented whether the use of whole-body MRI affected mortality and/or morbidity. Our systematic review confirms significant variability of technique and the lack of proven validity of MRI findings. The information could potentially be used to boost attempts towards standardization of technique, reporting and guidelines development.

Autoinflammatory diseases in childhood, part 2: polygenic syndromes

Autoinflammatory diseases are a family of disorders characterized by aberrant stimulation of inflammatory pathways without involvement of antigen-directed autoimmunity. They can be further divided in monogenic and polygenic types. Those without an identified genetic mutation are known as polygenic and include systemic-onset juvenile idiopathic arthritis, idiopathic recurrent acute pericarditis, Behçet syndrome, chronic recurrent multifocal osteomyelitis and inflammatory bowel disease among others. Autoinflammatory diseases are characterized by recurrent flares or persistent systemic inflammation and fever, as well as lymphadenopathy and cutaneous, abdominal, thoracic and articular symptoms. Although these syndromes can mimic infections clinically, the inflammatory lesions in autoinflammatory disorders are aseptic. However, because of their infrequency, varied and nonspecific presentation, and the new genetic identification, diagnosis is usually delayed. In this article, which is Part 2 of a two-part series, the authors review the main polygenic autoinflammatory diseases that can be seen in childhood, with special emphasis wherever applicable on imaging features that may help establish the correct diagnosis. However, the major role of imaging is to delineate organ involvement and disease extent.

Imaging mimics of chronic recurrent multifocal osteomyelitis: avoiding pitfalls in a diagnosis of exclusion

Chronic recurrent multifocal osteomyelitis (CRMO) is a pediatric autoinflammatory disorder that is characterized by multiple sterile inflammatory bone lesions with a relapsing and remitting course. CRMO belongs to the autoinflammatory family of rheumatologic disorders based on absence of significant titers of autoantibodies and autoreactive T-lymphocytes. In absence of pathognomonic clinical, radiographic or pathological features, diagnosis can be challenging. CRMO shares imaging features with other diseases. It is important for radiologists to be able to differentiate other diseases from CRMO because prognosis varies from completely benign to frankly malignant. In this article we first present the clinical and imaging features of CRMO to help readers gain an understanding of the disease process, then discuss our imaging approach to CRMO and review other disease processes that sometimes share similar imaging findings to CRMO and review differentiating features to help avoid misdiagnoses.

Development of a Scoring Tool for Chronic Nonbacterial Osteomyelitis Magnetic Resonance Imaging and Evaluation of its Interrater Reliability

OBJECTIVE

Serial magnetic resonance imaging (MRI) examinations are often needed in chronic nonbacterial osteomyelitis (CNO) to determine the objective response to treatment. Our objectives in this study were (1) to develop a consensus-based MRI scoring tool for clinical and research use in CNO; and (2) to evaluate interrater reliability and agreement using whole-body (WB)-MRI from children with CNO.

METHODS

Eleven pediatric radiologists discussed definitions and grading of signal intensity, size of signal abnormality within bone marrow, and associated features on MRI through monthly conference calls and a consensus meeting, using a nominal group technique in July 2017. WB-MRI scans from children with CNO were deidentified for training reading and an interrater reliability study. The reading by each radiologist was conducted in a randomized order. Interrater reliability for abnormal signal and severity were assessed using free-marginal κ statistics.

RESULTS

Radiologists reached a consensus on grading CNO-specific MRI findings and on describing bone units based on anatomy. A total of 45 sets of WB-MRI scans, including 4 sets of non-CNO MRI examinations, were selected for the final reading. The mean κ of each category of bones was > 0.7 with majority > 0.9 demonstrating substantial/almost perfect interrater reliability of readings among radiologists. The agreement on signal intensity and the size of signal abnormality within the most commonly affected bones (femur and tibia) were lower than those of other bones.

CONCLUSION

The chronic nonbacterial osteomyelitis magnetic resonance imaging scoring (CROMRIS) tool is a comprehensive standardized scoring tool for MRI in children with CNO. Our interrater study demonstrated good interrater reliability and agreement of readings.

Chronic Non-bacterial Osteomyelitis: A Review

Chronic non-bacterial osteomyelitis (CNO) is a rare auto-inflammatory bone disorder, with a prevalence of around one in a million patients. In the more severe form, it is referred to as chronic recurrent multifocal osteomyelitis (CRMO). We present the current knowledge on epidemiology, pathophysiology as well as diagnostic options and treatment regimens. CNO/CRMO most commonly affects children and lesions are often seen in the metaphyseal plates of the long bones, but cases have been described affecting all age groups as well as lesions in almost every bone. It is, therefore, a disease that clinicians can encounter in many different settings. Diagnosis is mainly a matter of exclusion from differential diagnoses such as bacterial osteomyelitis and cancer. Magnetic resonance imaging is the best radiological method for diagnosis coupled with a low-grade inflammation and a history of recurring episodes. Treatment is based on case reports and consists of alleviating symptoms with non-steroidal anti-inflammatory drugs since the disease is often self-limiting. Recently, more active treatments using either bisphosphonates or biological treatment are becoming more common, to prevent long term bone damage. In general, due to its rarity, much remains unclear regarding CNO/CRMO. We review the known literature on CNO/CRMO and propose areas of interest as well as possible ways to make current diagnostic criteria more detailed. We also find unifocal cases of the jaw to be a possible sub-type that may need its own set of criteria.

Whole-body magnetic resonance imaging: techniques and non-oncologic indications

Whole-body MRI is increasingly utilized for assessing oncologic and non-oncologic diseases in infants, children and adolescents. Focusing on the non-oncologic indications, this review covers technical elements required to perform whole-body MRI, the advantages and limitations of the technique, and protocol modifications tailored to specific indications. Rheumatologic diseases account for the majority of non-oncologic whole-body MRI performed in pediatric patients at the author's institution. Whole-body MRI helps in establishing the diagnosis, documenting disease extent and severity, and monitoring treatment response in enthesitis-related arthritis (ERA) and chronic recurrent multifocal osteomyelitis (CRMO). Other non-oncologic indications for whole-body MRI include osteomyelitis (usually pyogenic), pyrexia of unknown origin, neuromuscular disorders, inherited and inflammatory myopathies such as juvenile dermatomyositis and polymyositis, avascular necrosis, and fat/storage disorders. Use of whole-body MRI in postmortem imaging is rising, while whole-body MRI in non-accidental injury is considered to be of limited value. Imaging findings for a range of these indications are reviewed with whole-body MRI examples.

The role of whole-body magnetic resonance imaging in diagnosing chronic recurrent multifocal osteomyelitis

Chronic recurrent multifocal osteomyelitis (CRMO) is an uncommon idiopathic inflammatory disorder. The diagnosis is often delayed because a variable clinical presentation and limited awareness among care providers. We present an 11-year-old female diagnosed with CRMO and her imaging workup. In particular, this case highlights the role of whole-body magnetic resonance imaging to enhance detection and diagnosis of CRMO.

Bone metabolism and inflammatory characteristics in 14 cases of chronic nonbacterial osteomyelitis

BACKGROUND

Chronic nonbacterial osteomyelitis (CNO) is a multifocal autoinflammatory disease that often impairs daily life in children. This study aimed to investigate the bone metabolic and inflammatory characteristics of patients with CNO, and to assess the differences between responders and nonresponders to conservative treatment.

METHODS

We investigated the clinical symptoms; laboratory data including inflammatory and bone metabolic biomarkers; and imaging findings from plain radiography, magnetic resonance imaging (MRI), fluorodeoxyglucose-positron emission tomography (FDG-PET), and dual-energy x-ray absorption (DEXA) in 14 patients with CNO. All patients underwent first-line treatment comprising systemic nonsteroidal anti-inflammatory drugs with or without bisphosphonate. According to the response to the first-line treatment, the patients were divided into the clinical remission/partial response group and the no response group. The differences in bone metabolic and inflammatory characteristics between the two groups were assessed.

RESULTS

All patients had low bone mineral density assessed with DEXA. The bone metabolic biomarkers (bone-specific alkaline phosphatase and tartrate-resistant acid phosphatase 5b) were increased in boys of all ages and in young girls. Multiple inflammatory regions were detected in all patients by using FDG-PET including asymptomatic regions. The no response group had higher immunoglobulin G (IgG) and a greater number of bone inflammatory lesions detected on MRI than the clinical remission/partial response group.

CONCLUSION

Our data indicate the involvement of abnormal bone turnover, necessity of whole-body scanning, and association of higher serum IgG levels and greater numbers of inflammatory lesions with prolonged disease activity in patients with CNO.

Difficulty in the diagnosis of bone and joint pain associated with pediatric acute leukemia; comparison with juvenile idiopathic arthritis

OBJECTIVES

Acute leukemia often causes osteoarthralgia. The aim of this study is characterization of leukemia-associated osteoarthralgia in comparison with juvenile idiopathic arthritis (JIA).

METHODS

We retrospectively reviewed clinical records of 31 patients with acute leukemia and 13 patients with articular JIA diagnosed between January 2008 and March 2013. Clinical and laboratory findings at the initial examination were compared among the three groups; 10 leukemia with and 21 leukemia without osteoarthralgia and 13 JIA groups.

RESULTS

Eleven of the 31 leukemic patients (35%) had osteoarthralgia before the diagnosis of leukemia. Peripheral leukemic cells were initially absent in 10 of the 31 leukemia patients including three with osteoarthralgia. Platelet counts over 300 × 10⁹/L were common in JIA, but not in osteoarthralgia group. Mean serum lactate dehydrogenase levels were higher in both of the leukemia groups than JIA group but often within normal or near-normal levels in the leukemia groups. Magnetic resonance imaging was examined in three leukemic patients and demonstrated osteomyelitis-like bone marrow edema in two and periarticular infiltration similar to synovitis in one patient. Three leukemic patients with osteoarthralgia showed partial and transient responses to antibiotic therapy.

CONCLUSIONS

Leukemia-associated osteoarthralgia is often indistinguishable from rheumatic diseases by imaging and laboratory findings and should be confirmed by bone marrow examination.

Diagnostic performance of diffusion-weighted MR imaging in differentiation of diabetic osteoarthropathy and osteomyelitis in diabetic foot

PURPOSE

To study the diagnostic performance of diffusion weighted MR imaging in differentiation of diabetic osteoarthropathy and osteomyelitis in diabetic foot.

PATIENTS AND METHODS

This prospective study was carried out on 41 patients with diabetic foot, 22 males and 19 females with mean age of 51 years. They underwent diffusion-weighted MR imaging of the foot. The apparent diffusion coefficient (ADC) values of the bony lesions were calculated by two reviewers and correlated with the surgical findings or biopsy. The kappa statistic (k) was used to estimate the proportion of inter-observer agreement of two reviewers.

RESULTS

The mean ADC of acute diabetic osteoarthropathy was 1.27±0.19×10^-3mm²/s for reviewer 1 and 1.26±0.21×10^-3mm²/s for reviewer 2. The mean ADC value in diabetic osteomyelitis was 0.86±0.11×10^-3mm²/s for reviewer 1 and 0.85±0.12×10^-3mm²/s for reviewer 2. There was excellent inter-observer agreement of ADC value of bony lesions in diabetic foot by both reviewers (K=0.93). There was statistically significant difference in the ADC values of both groups (P=0.001). The cut-off point of ADC value of both reviewers used in differentiating acute diabetic osteoarthropathy and osteomyelitis were 0.98×10^-3mm²/s and 1.04×10^-3mm²/s with an accuracy of 94% and 93% and area under the curve of 0.94 and 0.93 respectively.

CONCLUSION

We conclude that the ADC value is a non-invasive imaging parameter that can help in differentiation of diabetic osteoarthropathy from osteomyelitis with excellent inter-observer agreement.

Whole-body MRI in children: Would a 3D STIR sequence alone be sufficient for investigating common paediatric conditions? A comparative study

OBJECTIVES

To test the performance of a single 3D IR T2-Weighted sequence compared to a Whole-body MRI protocol including DWI, T1-Weighted and STIR 3D IR (3S) in a pediatric population.

METHODS

Two radiologists (15 and 30 years of experience),reviewed WBMRIs: first the STIR alone and 2 weeks later the 3S protocol. The indications were variable. Only positive findings were explicitly reported. A third reader compared the results to gold standard (GS) exams specific for the pathology. Agreement between the two readers, sensitivity and positive predictive value of STIR were calculated.

RESULTS

fifty-four WBMRIs were included (16 suspected child abuse, 8 chronic recurrent multifocal osteomyelitis (CRMO), 11 lymphomas, 4 osteosarcomas, 9 neuroblastomas, 6 histiocytosis). The mean age was 6 years 10 months, range: 1 month to 15 years. Agreement between readers was of 0.87 [0.82-0.91] for 3D STIR, and 0.89 [0.83-0.93] for the 3S protocol. For reader 1 sensitivity of 3D STIR was 81.6% and of 3S 81.0%. For reader 2 it was 74.1% for 3D STIR and 74.7% for 3S. For both readers and for both protocols, the positive predictive value (PPV) depended on the type of disease (for example 100% histocytosis and osteosarcomas, >90% for child abuse, >85% CRMO but <70% for lymphoma and neuroblastoma).

CONCLUSIONS

Sensitivities were not different between the 2 protocols, for each reader and were different between the 2 readers for each protocol.