Preferential involvement of the pelvis and hips along with active sacroiliitis in chronic nonbacterial osteomyelitis: MRI of 97 patients from a single tertiary referral center.

OBJECTIVE: To present MRI distribution of active osteitis in a single tertiary referral center cohort of patients with chronic nonbacterial osteomyelitis (CNO). METHODS: Two musculoskeletal radiologists retrospectively reviewed MRI examinations of all patients with a final clinical diagnosis of CNO over 15 years. Sites of active osteitis at any time during the course of disease were divided into seven groups: (A) mandible, sternum, clavicles, or scapulas; (B) upper extremities; (C) subchondral sacrum and ilium immediately subjacent to sacroiliac joints (active osteitis denoting "active sacroiliitis" here); (D) pelvis and proximal 1/3 of femurs (excluding group C); (E) bones surrounding knees including distal 2/3 of femurs and 1/2 of proximal tibias and fibulas; (F) distal legs (including distal 1/2 of tibias and fibulas), ankles, or feet; (G) spine (excluding group C). Temporal changes of lesions in response to treatment (or other treatment-related changes such as pamidronate lines) were not within the scope of the study. RESULTS: Among 97 CNO patients (53 males [55%], 44 females; age at onset, mean ± SD, 8.5 ± 3.2 years; age at diagnosis, 10.3 ± 3.3 years), whole-body (WB) MRI was performed in 92%, mostly following an initial targeted MRI (94%). A total of 557 (346 targeted and 211 WB) MRIs were analyzed. Biopsy was obtained in 39 patients (40%), all consistent with CNO or featuring supporting findings. The most common locations for active osteitis were groups D (78%; 95% CI 69‒85%) and C (72%; 95% CI 62‒80%). CONCLUSION: Pelvis and hips were preferentially involved in this cohort of CNO patients along with a marked presence of active sacroiliitis. CLINICAL RELEVANCE STATEMENT: When suggestive findings of CNO are identified elsewhere in the body, the next targeted site of MRI should be the pelvis (entirely including sacroiliac joints) and hips, if whole-body MRI is not available or feasible. KEY POINTS: • Heavy reliance on MRI for diagnosis of CNO underscores the importance of suggestive distribution patterns. • Pelvis and hips are the most common (78%) sites of CNO involvement along with active sacroiliitis (72%). • Pelvis including sacroiliac joints and hips should be targeted on MRI when CNO is suspected.

Chondro-osseous border in baby hip ultrasonography for developmental dysplasia of the hip: an indispensable litmus paper for the accuracy of scientific publications.

PURPOSE: The aim of our study was to use the chondro-osseous border (COB) as an indispensable assessment criterion to evaluate the quality of baby hip ultrasonography (US) images in the literature pertaining to the application of Graf's technique. MATERIALS AND METHODS: Our literature review search yielded 144 articles. Of these, 41 contained images that were stated to be based on the application of Graf's technique. Two reviewers, a radiologist and an orthopaedic surgeon, both course instructors for the use of baby hip US for developmental dysplasia of the hip (DDH), independently evaluated the articles to assess the diagnostic validity of the published images on the basis of a single criterion: the identification of the COB. RESULTS: Of the 41 articles which were analyzed, 15 contained images without a COB, which corresponds to 36% (roughly, one out of three). Articles from countries where universal screening is performed (Germany, Italy, Switzerland, Mongolia) were all correct. All the articles from Turkey, a country which has made significant contribution with published material about Graf's technique over many years, and most of the articles from China (80%), where Graf's technique has become popular in recent years, contained correct images. CONCLUSION: Published literature lacks strict criteria for the publication of correct images corresponding to Graf's technique in baby hip US. This fact raises concerns about the quality of published material (and, as a corollary, the quality of clinical application of the technique) and should have ramifications on scientific journal policies regarding the publication of such manuscripts.

Glenoid Track Assessment at Imaging in Anterior Shoulder Instability: Rationale and Step-by-Step Guide.

Anterior shoulder dislocation is the most common form of joint instability in humans, usually resulting in soft-tissue injury to the glenohumeral capsuloligamentous and labral structures. Bipolar bone lesions in the form of fractures of the anterior glenoid rim and posterolateral humeral head are often associated with anterior shoulder dislocation and can be a cause or result of recurrent dislocations. Glenoid track assessment is an evolving concept that incorporates the pathomechanics of anterior shoulder instability into its management. Currently widely endorsed by orthopedic surgeons, this concept has ramifications for prognostication, treatment planning, and outcome assessment of anterior shoulder dislocation. The glenoid track is the contact zone between the humeral head and glenoid during shoulder motion from the neutral position to abduction and external rotation. Two key determinants of on-track or off-track status of a Hill-Sachs lesion (HSL) are the glenoid track width (GTW) and Hill-Sachs interval (HSI). If the GTW is less than the HSI, an HSL is off track. If the GTW is greater than the HSI, an HSL is on track. The authors focus on the rationale behind the glenoid track concept and explain stepwise assessment of the glenoid track at CT or MRI. Off-track to on-track conversion is a primary goal in stabilizing the shoulder with anterior instability. The key role that imaging plays in glenoid track assessment warrants radiologists' recognition of this concept along with its challenges and pitfalls and the production of relevant and actionable radiology reports for orthopedic surgeons-to the ultimate benefit of patients. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Imaging in crush injury: a spectrum of findings in survivors of the twin earthquakes on February 6, 2023.

On February 6, two major earthquakes with magnitudes of 7.8 and 7.7 on the Richter scale hit Turkey and Northern Syria causing more than 50,000 deaths. In the immediate aftermath of the earthquakes, our major tertiary medical referral center received dozens of cases of crush syndrome, presenting with a variety of imaging findings. Crush syndrome is characterized by hypovolemia, hyperkalemia, and myoglobinuria that can lead to rapid death of victims, despite their survival of staying under wreckage for days. The typical triad of crush syndrome consists of the acute tubular necrosis, paralytic ileus, and third-space edema. In this article, we focus primarily on characteristic imaging findings of earthquake-related crush syndrome and divided them into two distinct subsections: myonecrosis, rapid hypovolemia, excessive third-space edema, acute tubular necrosis, and paralytic ileus, which are directly related to crush syndrome, and typical accompanying findings of earthquake-related crush syndrome. Lower extremity compression in earthquake survivors results in the typical third-space edema. In addition to the lower extremities, other skeletal muscle regions are also affected, especially rotator muscles, trapezius, and pectoral muscles. Although it may be relatively easy to better detect myonecrosis with contrast-enhanced CT scans, changing the windowing of the images may be helpful.

Sacroiliac joint involvement in osteochondromatosis: identifying its prevalence and characteristics from cross-sectional imaging

PURPOSE: Apart from a few case reports, sacroiliac joint (SIJ) involvement in osteochondromatosis has not been studied. We aimed to determine the prevalence and characteristics of such involvement using cross-sectional imaging. METHODS: In this retrospective study, three observers (one junior radiologist and two musculoskeletal radiologists) independently reviewed computed tomography (CT) or magnetic resonance imaging (MRI) of patients in our database who had osteochondromatosis (≥2 osteochondromas across the skeleton) for SIJ involvement. The final decision was reached by the consensus of the two musculoskeletal radiologists in a later joint session. RESULTS: Of the 36 patients with osteochondromatosis in our database, 22 (61%) had cross-sectional imaging covering SIJs (14 females, 8 males; age range 7-66 years; mean age 23 years; 13 MRI, 9 CT). Of these, 16 (73%) had intra-articular osteochondromas. For identifying SIJ osteochondromas on cross-sectional imaging, interobserver agreement was substantial [κ = 0.67; 95% confidence interval (CI): 0.34, 1.00] between the musculoskeletal radiologists and moderate (κ = 0.59; 95% CI: 0.23, 0.94) between the junior radiologist and the final consensus decision of the two musculoskeletal radiologists. In the cohort with cross-sectional imaging, the anatomical variations of the accessory SIJ (n = 6, 27%) and iliosacral complex (n = 2, 9%) were identified in six different patients with (n = 2) and without (n = 4) sacroiliac osteochondromas. CONCLUSION: Cross-sectional imaging shows frequent (73%) SIJ involvement in osteochondromatosis, which, although a rare disorder, nevertheless needs to be considered in the differential diagnosis of such SIJ anatomical variants as the accessory SIJ and iliosacral complex. Differentiating these variants from osteochondromas is challenging in patients with osteochondromatosis.

A snapshot of teleradiology practice in Turkey: the results of a survey among radiologists.

PURPOSE: This study featured a survey that offers a snapshot of various teleradiology practices in Turkey, a Group of Twenty country that has undertaken a major transformation of its health care system during the last two decades and is currently the world leader in terms of the combined number of per capita magnetic resonance imaging and computed tomography examinations performed (which represent the bulk of teleradiology services worldwide). METHODS: The study data was collected from 4736 Turkish Society of Radiology (TSR) members via an electronic platform in the web environment through a questionnaire consisting of 24 questions. The survey was conducted in a 3-month time window (March-May 2021). Statistical tools were used for the analysis of the quantitative data. RESULTS: Responses from 156 members of the TSR comprised the study data, revealing that teleradiology is used for various applications in Turkey. Almost half of the participants (49%) performed teleradiology only in the private sector. Half of the respondents (51%) stated that they reported images at home for multiple centers. Moreover, 38% of the participants had been reporting more than 50 examinations per day, and 74% of the respondents earned less than 0.50 Euro per examination they reported. The overall satisfaction with teleradiology among the teleradiologists was, on average, 4.7 out of 10 points. CONCLUSION: The results are both promising for the future (i.e., concerning the propensity for adopting new technology) and alarming for the current state of affairs (i.e., insufficient radiologist reimbursement and lack of licensing and accreditation of teleradiology service providers). Periodic surveys performed in countries with different health care systems concerning financial, technical, and medicolegal aspects might reveal an up-to-date landscape of teleradiology practices worldwide and help guide local and regional decision-makers.

Imaging Osteomyelitis: An Update.

BACKGROUND: Hematogenous osteomyelitis has increased over the past quarter century in frequency, virulence, and degree of soft-tissue involvement, bringing about changes in clinical manifestations and management of the disease especially in children that should be reflected in the current imaging approach. Likewise, the global disease burden of diabetes has increased greatly in the same period, compounding the problem of ascertaining osteomyelitis in diabetic foot. METHOD: This article provides an updated overview of imaging findings in hematogenous and contiguous osteomyelitis based on the literature and our institutional experience, along with salient features of recent recommendations from expert groups on the diagnostic algorithms and reporting terminology. RESULTS AND CONCLUSION: Findings on radiography and especially magnetic resonance imaging (MRI) closely reflect pathophysiology in osteomyelitis, whereby the characteristic involvement of the metaphysis or metaphyseal-equivalents, the formation and subperiosteal extension of intramedullary pus collection, and the development of cloaca, sequestrum, and involucrum are all diagnostic clues. Non-enhancing foci within the medullary bone, the penumbra sign, intra- or extramedullary fat globules, and surrounding soft tissue inflammation or abscesses are among key MRI findings. Diabetic foot is a special condition with characteristic pathophysiologic and imaging features that suggest the likelihood of osteomyelitis and the main differential diagnostic consideration of acute on chronic neuropathic osteoarthropathy with or without osteomyelitis. KEY POINTS: · Imaging closely reflects pathophysiology in hematogenous osteomyelitis.. · Acute hematogenous osteomyelitis predominantly involves metaphyses and metaphyseal equivalent sites.. · MRI clues for hematogenous osteomyelitis include central marrow non-enhancement, intra- or extramedullary fat globules, and the "penumbra" sign.. · An increased fluid-sensitive MRI bone signal abutting a soft tissue ulcer, abscess, or sinus tract suggests a high probability of contact osteomyelitis.. CITATION FORMAT: · Aydingoz U, Imaging Osteomyelitis: An Update. Fortschr Röntgenstr 2023; 195: 297 - 308.

Determinants of in-hospital muscle loss in acute ischemic stroke - Results of the Muscle Assessment in Stroke Study (MASS).

BACKGROUND & AIMS: There is a change in the mass and composition of paretic and non-paretic skeletal muscles in the chronic phase of stroke. The multi-center, prospective, and observational Muscle Assessment in Stroke Study (MASS) was performed to evaluate the degree of muscle loss during the in-hospital acute stroke setting and determine factors contributing to this loss. METHODS: Acute dysphagic ischemic stroke patients (n = 107) admitted to neuro-intensive care units were evaluated by computed tomography on days 1 and 14 after admission to determine the cross-sectional muscle area (CSMA) at the level of the mid-humerus, mid-thigh, and third lumbar vertebra. The percentage change in CSMA and variables associated with this change were evaluated by univariate and multivariate analyses. RESULTS: There were significant reductions in CSMA in all the muscle groups analyzed; the most prominent change was observed in the arms (both: 14.2 ± 10.7%; paretic: 17.7 ± 11.6%; non-paretic: 10.1 ± 12.5%), followed by the muscles in the legs (both: 12.4 ± 8.7%; paretic: 12.9 ± 9.9%; non-paretic: 12.0 ± 9.3%) and L3-vertebra level (5.6 ± 9.8%) (P < 0.001 for all). Higher calorie (r = -0.378, P < 0.001) or protein (r = -0.352, P < 0.001) intake was negatively associated with the decrease in CSMA of upper extremities. A substantial protein (≥0.4 g/kg/d) or calorie (≥5 kcal/kg/d) gap between targeted or actual intake was related to a larger decrease in CSMA in all the anatomic regions (P ≤ 0.05 for all). Other significant predictors of muscle loss included history of diabetes mellitus, male sex, higher BMI, in-hospital infections, and the necessity for invasive mechanical ventilation. CONCLUSIONS: There is a considerable degree of loss in the global muscle mass in acute ischemic stroke patients over a two-week period. Along with several factors, falling significantly behind the daily protein or calorie targets was related to the decrease in the muscle area. TRIAL REGISTRATION INFORMATION: clinicaltrials.gov identifier NCT03825419.

A Child with Refractory and Relapsing Anti-3-Hydroxy-3-Methylglutaryl-Coenzyme A Reductase Myopathy: Case-Based Review.

BACKGROUND/OBJECTIVE: Anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (anti-HMGCR) myopathy is rare in children. Here, we present a boy with relapsing refractory anti-HMGCR myopathy along with a systematic literature review. CASE REPORT: 17-year-old boy with five years of muscle weakness, rash, high creatinine kinase (CK) levels, and muscle biopsy compatible with inflammatory myopathy was diagnosed with juvenile dermatomyositis. He was treated with corticosteroids, intravenous immunoglobulin (IVIG), and methotrexate. His muscle weakness improved with this treatment although never completely resolved. CK levels decreased from ∼15000 U/L to ∼3000 U/L. At the age of 15, muscle weakness relapsed after an upper respiratory tract infection; pulse corticosteroid treatment was administered. The re-evaluated muscle biopsy showed a necrotizing pattern and the HMGCR antibody was positive confirming anti-HMGCR myopathy when he was 16. The diagnostic delay was 50 months. Disease activity was monitored by Medical Research Council score, MRI and functional tests. Despite corticosteroids, methotrexate, IVIG, cyclosporine A, and rituximab therapies, muscle weakness improved only slightly during the first three months and remained stable afterwards.Results of the Literature Search:We identified 16 articles describing 50 children (76% female) with anti-HMGCR myopathy by reviewing the English literature up to March 1st, 2022. Proximal muscle weakness was the most common clinical symptom (70.8%). Corticosteroids (84.8%), IVIG (58.7%), and methotrexate (56.5%) were preferred in most cases. Complete remission was achieved in nine patients (28.1%). CONCLUSION: Diagnosis and management of children with anti-HMGCR myopathy are challenging. Complete remission is achieved in only one third of these patients. Imaging biomarkers may aid treatment.

Optimization of the Grashey View Radiograph for Critical Shoulder Angle Measurement: A Reliability Assessment With Zero Echo Time MRI.

Background: Suboptimal positioning on Grashey view radiographs may limit the prognosticating potential of the critical shoulder angle (CSA) for shoulder disorders. Purpose: To investigate whether radiography optimized according to the latest research is reliable for measuring CSA in comparison with magnetic resonance imaging (MRI) featuring 3-dimensional (3D) zero echo time (ZTE) sequencing, which accentuates the contrast between cortical bone and surrounding soft tissue with high fidelity. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Patients with shoulder pain were prospectively and consecutively enrolled. All patients had Grashey view radiographs as well as 3.0-T MRI scans with isotropic 3D ZTE sequencing. Acceptable positioning on the radiographs was determined using the ratio of the transverse to longitudinal (RTL) diameter of the lateral glenoid outline; radiographs with an RTL ≥0.25 were repeated. Two observers independently measured the CSA on the radiographs and the coronal oblique reformatted ZTE images, the latter including verification of measurement points by cross-referencing against images from other planes. Reliability of measurements between observers and modalities was analyzed with the intraclass correlation coefficient (ICC). The paired-samples t test was used to compare the differences between imaging modalities. Results: Enrolled were 65 patients (35 female and 30 male; mean age, 40.2 years; range, 25-49 years). Radiographs with optimal positioning (RTL < 0.25) were attained after a mean of 1.6 exposures (range, 1-4); the mean RTL was 0.09 (range, 0-0.20). Interobserver agreement of CSA was excellent for radiographs (ICC = 0.91; 95% CI, 0.84-0.94) and good for ZTE MRI scans (ICC = 0.85; 95% CI, 0.71-0.92). Intermodality agreement of CSA between radiographs and ZTE MRI scans was moderate (ICC = 0.66; 95% CI, 0.48-0.73). The CSA was significantly different between an optimal radiograph (30.7° ± 4.3°) and ZTE MRI scan (31.8° ± 3.8) (P = .005). Subgroup analysis revealed no significant differences in CSA measurement between ZTE MRI scans and Grashey view radiographs with an RTL of <0.1 (P = .08). Conclusion: CSA measurement on ZTE MRI scans with anatomic point cross-referencing was significantly different from that on Grashey view radiographs, even with optimal positioning, and radiography may necessitate more than 1 exposure. An RTL of <0.1 ensured reliability of radiographs when other standards of sufficient x-ray exposure were met.

Zero Echo Time Musculoskeletal MRI: Technique, Optimization, Applications, and Pitfalls.

Zero echo time (ZTE) imaging is an MRI technique that produces images similar to those obtained with radiography or CT. In ZTE MRI, the very short T2 signal from the mineralized trabecular bone matrix and especially cortical bone-both of which have a low proton density (PD)-is sampled in a unique sequence setup. Additionally, the PD weighting of the ZTE sequence results in less contrast between soft tissues. Therefore, along with gray-scale inversion from black to white and vice versa, ZTE imaging provides excellent contrast between cortical bone and soft tissues similar to that of radiography and CT. However, despite isotropic or near-isotropic three-dimensional (3D) imaging capabilities of the ZTE sequence, spatial resolution in this technique is still inferior to that of radiography and CT, and 3D volume renderings are currently time-consuming and require postprocessing software that features segmentation and manual contouring. Optimization of ZTE MRI mostly entails adjustments of bandwidth, flip angle, field of view, and image matrix. A wide range of structural abnormalities and disease or healing processes in the musculoskeletal system are well delineated with ZTE MRI, including conditions that involve bone-based morphometric analyses (which aid diagnosis, help prognostication, and guide surgery), impaction, avulsion and stress fractures, loose bodies or erosions in and around joints, soft-tissue calcifications and ossifications, and bone tumors (including treatment response). The pitfalls of ZTE imaging include mimics of foci of calcification or ossification such as intra-articular gas and susceptibility artifacts from surgical materials and hemosiderin deposition, which can be avoided in many instances by cross-referencing images obtained with other MRI sequences. Online supplemental material is available for this article. ©RSNA, 2022.

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.

Machine learning identifies factors related to early joint space narrowing in dysplastic and non-dysplastic hips.

OBJECTIVES: To utilise machine learning, unsupervised clustering and multivariate modelling in order to predict severe early joint space narrowing (JSN) from anatomical hip parameters while identifying factors related to joint space width (JSW) in dysplastic and non-dysplastic hips. METHODS: A total of 507 hip CT examinations of patients 20-55 years old were retrospectively examined, and JSW, center-edge (CE) angle, alpha angle, anterior acetabular sector angle (AASA), and neck-shaft angle (NSA) were recorded. Dysplasia and severe JSN were defined with CE angle < 25o and JSW< 2 mm, respectively. A random forest classifier was developed to predict severe JSN based on anatomical and demographical data. Multivariate linear regression and two-step unsupervised clustering were performed to identify factors linked to JSW. RESULTS: In dysplastic hips, lateral or anterior undercoverage alone was not correlated to JSN. AASA (p < 0.005) and CE angle (p < 0.032) were the only factors significantly correlated with JSN in dysplastic hips. In non-dysplastic hips, JSW was inversely correlated to CE angle, AASA, and age and positively correlated to NSA (p < 0.001). A random forest classifier predicted severe JSN (AUC 69.9%, 95%CI 47.9-91.8%). TwoStep cluster modelling identified two distinct patient clusters one with low and one with normal JSW and different anatomical characteristics. CONCLUSION: Machine learning predicted severe JSN and identified population characteristics related to normal and abnormal joint space width. Dysplasia in one plane was found to be insufficient to cause JSN, highlighting the need for hip anatomy assessment on multiple planes. KEY POINTS: • Neither anterior nor lateral acetabular dysplasia was sufficient to independently reduce joint space width in a multivariate linear regression model of dysplastic hips. • A random forest classifier was developed based on measurements and demographic parameters from 507 hip joints, achieving an area under the curve of 69.9% in the external validation set, in predicting severe joint space narrowing based on anatomical hip parameters and age. • Unsupervised TwoStep cluster analysis revealed two distinct population groups, one with low and one with normal joint space width, characterised by differences in hip morphology.

Different Attenuation Models of Diffusion-Weighted MR Imaging for the Differentiation of Benign and Malignant Musculoskeletal Tumors.

BACKGROUND: Several functional imaging techniques, including monoexponential diffusion-weighted imaging (m-DWI), intravoxel incoherent motion (IVIM), and diffusion kurtosis (DK) imaging, have been used in differentiating benign and malignant musculoskeletal tumors. Combining all three techniques in the same study population may improve differentiation. PURPOSE: To compare the diagnostic performance of m-DWI, IVIM, and DK models and their combinations in differentiating benign and malignant musculoskeletal tumors. STUDY TYPE: Prospective. POPULATION: Fifty patients with benign and malignant musculoskeletal tumors divided into nonmyxoid and nonchondroid and myxoid and/or chondroid subgroups. FIELD STRENGTH/SEQUENCE: A 1.5 T/m-DWI, IVIM, and DK single-shot spin-echo echo-planar sequences. ASSESSMENT: Minimum and volumetric values of apparent diffusion coefficient (ADC), pure molecular diffusion (Divim ), pseudodiffusion (D*), perfusion fraction (f), diffusion coefficient for kurtosis model (DK ), and Kurtosis (K) were compared between all benign and malignant tumors. Subgroup analysis was also performed for nonmyxoid and nonchondroid and myxoid and/or chondroid tumors. STATISTICAL TESTS: Independent samples t-test, Mann-Whitney U test, intraclass correlation coefficient, ROC analysis, and logistic regression analysis. A P value < 0.05 was considered statistically significant. RESULTS: ADCmin , Divim-min , D*vol , DK-min, Kvol, and Kmin values showed statistically significant differences between all benign and malignant tumors and nonmyxoid and nonchondroid tumor subgroup. Kmin showed the highest diagnostic performance in differentiating benign and malignant tumors with AUCs of 0.760 for "all tumors" and 0.825 for the nonmyxoid and nonchondroid tumor subgroup. No significant differences were detected in m-DWI-, IVIM-, and DK-derived parameters for differentiating benign and malignant myxoid and/or chondroid tumors. Only three of 63 combinations of prediction models demonstrated a higher diagnostic performance than Kmin ; however, improvements were not significantly different. DATA CONCLUSION: ADCmin , Divim-min , D*vol , DK-min , Kvol , and Kmin values can be used to differentiate benign and malignant musculoskeletal tumors. Our findings suggest that the added value of multiparametric approach in such differentiation is not significant. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 2.

Spinal involvement in juvenile idiopathic arthritis: what do we miss without imaging?

Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease of childhood. Enthesitis-related arthritis (ERA) has been one of the most controversial subtypes of JIA with a higher risk of axial involvement.  Our aim was to assess the frequency and spectrum of MRI findings of spine involvement in patients with JIA and determine if the axial involvement is always clinically symptomatic in patients with positive MRI findings. In this retrospective cross-sectional observational study we included known or suspected JIA patients who underwent spinal MRI examination between 2015 and 2017 and followed up in the Pediatric Rheumatology outpatient clinic. The demographic and clinical data were reviewed from the medical charts and electronic records. All patients were grouped as clinically symptomatic and asymptomatic for spinal involvement and MRI findings were re-evaluated for presence of inflammatory and erosive lesions. Of the 72 JIA patients, 57 (79.2%) were diagnosed with ERA, and 15 (20.8%) with non-ERA subtypes of JIA. Overall, 49 (68%) patients with JIA had positive spinal MRI findings (inflammatory and/or erosive lesions). Twenty-seven (47%) ERA patients were clinically symptomatic for spine involvement and among them, 19 (70.3%) had positive spinal MRI findings. Although 30 ERA (53%) patients were clinically asymptomatic, 23 of them (77%) had positive spinal MRI findings, as well. Eleven (73%) patients diagnosed with non-ERA JIA subtypes were clinically symptomatic for spine involvement at the time of MRI. Among them, four (36.3%) had inflammatory and/or erosive lesions on spine MRI. Four (26%) non-ERA patients were clinically asymptomatic for spine involvement, but three (75%) of them showed positive findings on spinal MRI. Inflammatory and/or erosive lesions of the thoracolumbar spine could exist in patients with JIA, regardless of the presence of symptoms. Not only because the significant proportion of ERA patients show asymptomatic axial involvement but also the presence of axial involvement in patients who were classified as non-ERA depending on current ILAR classification underlines the necessity of using MRI for accurate classification of patients with JIA.