Sacroiliac joint beyond sacroiliitis-further insights and old concepts on magnetic resonance imaging.

The sacroiliac joint (SIJ) is an amphiarthrosis composed of a posterior syndesmosis and an anterior cartilaginous portion, with limited yet present mobility. Its main function is to transmit the load from the axial skeleton to the lower limbs and vice-versa; it is susceptible to early mechanical and degenerative changes which are much more common than inflammatory sacroiliitis. Magnetic resonance imaging (MRI) has increasingly been used to evaluate these changes, and while subchondral bone marrow edema (BME) is a common finding related to both, care must be taken when applying the ASAS research MRI definition for sacroiliitis without considering lesion BME topography, size and depth, concomitant structural damage and, of course, the clinical picture. In this review, we will discuss the anatomy and biomechanics of the SIJ, the noninflammatory causes of SIJ subchondral BME, and how these concepts combined can be used to increase our diagnostic confidence.

O papel da estereorradiografia na avaliação das deformidades dos membros inferiores.

As deformidades dos membros inferiores são uma condição comum e podem levar a alterações da marcha e afetar a função e longevidade das articulações do quadril, do joelho e da coluna. Uma abordagem diagnóstica sistemática é essencial para definir o tratamento e alcançar o resultado terapêutico desejado com a menor taxa de complicações. A radiografia panorâmica é frequentemente utilizada para caracterizar as deformidades dos membros inferiores por meio de medidas de comprimento e desvios angulares dos eixos, além de se tratar de um método de baixo custo e alta disponibilidade. No entanto, como é frequente a combinação de deformidades em dois ou três planos ortogonais dos membros, a avaliação radiográfica perde acurácia por se tratar de um método de imagem bidimensional. Nesse sentido, deformidades em valgo/varo avaliadas radiograficamente no plano coronal apresentarão variações crescentes nas medidas dependendo do grau de flexão/recurvatum, torções ósseas anômalas ou, não menos importante, um posicionamento inadequado. A estereorradiografia biplanar de baixa dose, por meio de modelos tridimensionais, permite obter medidas mais acuradas de vários parâmetros usados na avaliação das deformidades dos membros inferiores, incluindo comprimentos, eixos e as torções tibial e femoral, antes disponíveis apenas pela tomografia computadorizada, com a vantagem de ser realizada em posição funcional com carga. Além disso, por permitir uma avaliação global da cabeça aos pés, abre uma nova perspectiva de compreender a inter-relação das deformidades dos membros com o posicionamento da bacia e com as deformidades da coluna.

O papel da estereorradiografia na avaliação das deformidades dos membros inferiores / The role of stereoradiography in the evaluation of lower limb deformities

Resumo As deformidades dos membros inferiores são uma condição comum e podem levar a alterações da marcha e afetar a função e longevidade das articulações do quadril, do joelho e da coluna. Uma abordagem diagnóstica sistemática é essencial para definir o tratamento e alcançar o resultado terapêutico desejado com a menor taxa de complicações. A radiografia panorâmica é frequentemente utilizada para caracterizar as deformidades dos membros inferiores por meio de medidas de comprimento e desvios angulares dos eixos, além de se tratar de um método de baixo custo e alta disponibilidade. No entanto, como é frequente a combinação de deformidades em dois ou três planos ortogonais dos membros, a avaliação radiográfica perde acurácia por se tratar de um método de imagem bidimensional. Nesse sentido, deformidades em valgo/varo avaliadas radiograficamente no plano coronal apresentarão variações crescentes nas medidas dependendo do grau de flexão/recurvatum, torções ósseas anômalas ou, não menos importante, um posicionamento inadequado. A estereorradiografia biplanar de baixa dose, por meio de modelos tridimensionais, permite obter medidas mais acuradas de vários parâmetros usados na avaliação das deformidades dos membros inferiores, incluindo comprimentos, eixos e as torções tibial e femoral, antes disponíveis apenas pela tomografia computadorizada, com a vantagem de ser realizada em posição funcional com carga. Além disso, por permitir uma avaliação global da cabeça aos pés, abre uma nova perspectiva de compreender a inter-relação das deformidades dos membros com o posicionamento da bacia e com as deformidades da coluna.

Abstract Deformities of the lower limbs are a common condition and can lead to changes in gait, as well as affecting the function and longevity of the hips, knees, and spine. A systematic approach is essential to achieve the desired therapeutic result with the lowest rate of complications. Panoramic radiography is a widely available, low-cost method that is commonly used in order to assess the length and angular deformities of the lower limbs, by measuring the length and angular deviations of the axes. However, because the combination of lower limb deformities in two or three orthogonal planes is common, conventional radiography lacks accuracy because it is a two-dimensional imaging method. Therefore, the measurements of valgus/varus deformities on X-rays restricted to the coronal plane will present increasing variations in measurements depending on the degree of flexion/recurvatum alignment, anomalous bone torsions, or, last but not least, inappropriate patient positioning. Low-dose biplanar stereoradiography using three-dimensional models increases the accuracy of the measurement of several parameters used in the evaluation of lower limb alignment, including lengths, axes, and tibial/femoral torsions, parameters that could previously be evaluated only by computed tomography. Stereoradiography also makes it possible to perform a head-to-toe evaluation, as well as to evaluate the interactions among the lower limbs, pelvis, and spine.

Knee MR Using a Body Coil is Equivalent to CT in Measuring the TT-TG Distance: Removing the Systematic Bias.

Objective To compare magnetic resonance imaging (MRI) using a body coil with computed tomography (CT) in measuring the tibial tubercle-trochlear groove distance (TT-TG) and the patellar tendon-cartilaginous trochlear groove (PT-CTG) distances, and evaluate interrater reliability. Methods The study group consisted of 34 knees from 17 asymptomatic subjects with no history of knee pathology, trauma or surgery. A low-dose CT scan and an axial T1-weighted MRI sequence of the knees were performed with rigorous standardization of the positioning with full extension of the knees and parallel feet. Two musculoskeletal radiologists performed the measurements independently. The reliability of the TT-TG and PT-CTG distances on CT (17.1 ± 4.2 mm and 17.3 ± 4.2 mm) and of MRI (16.2 ± 3.7 mm and 16.5 ± 4.1 mm) was assessed by intraclass correlation coefficient (ICC [2,1]) and Bland-Altman graphs, as well as the interrater reliability for both methods. Results Good reliability and agreement was observed between CT and MRI measurements for TT-TG and PT-CTG, with an ICC of 0.774 ( p < 0.001) and 0.743 ( p < 0.001), respectively, and no systematic bias was observed. The interrater reliability was excellent for all measurements on both imaging methods. Conclusion This was the first study that compared MRI using a body coil with CT in measuring the TT-TG distance, with the potential clinical implication that the CT in this clinical setting could be avoided.

Knee MR Using a Body Coil is Equivalent to CT in Measuring the TT-TG Distance: Removing the Systematic Bias / A ressonância magnética do joelho usando a bobina de corpo é equivalente à TC na medição da distância TT-ST: Removendo o viés sistemático

Abstract Objective To compare magnetic resonance imaging (MRI) using a body coil with computed tomography (CT) in measuring the tibial tubercle-trochlear groove distance (TT-TG) and the patellar tendon-cartilaginous trochlear groove (PT-CTG) distances, and evaluate interrater reliability. Methods The study group consisted of 34 knees from 17 asymptomatic subjects with no history of knee pathology, trauma or surgery. A low-dose CT scan and an axial T1-weighted MRI sequence of the knees were performed with rigorous standardization of the positioning with full extension of the knees and parallel feet. Two musculoskeletal radiologists performed the measurements independently. The reliability of the TT-TG and PT-CTG distances on CT (17.1 ± 4.2 mm and 17.3 ± 4.2 mm) and of MRI (16.2 ± 3.7 mm and 16.5 ± 4.1 mm) was assessed by intraclass correlation coefficient (ICC [2,1]) and Bland-Altman graphs, as well as the interrater reliability for both methods. Results Good reliability and agreement was observed between CT and MRI measurements for TT-TG and PT-CTG, with an ICC of 0.774 (p< 0.001) and 0.743 (p< 0.001), respectively, and no systematic bias was observed. The interrater reliability was excellent for all measurements on both imaging methods. Conclusion This was the first study that compared MRI using a body coil with CT in measuring the TT-TG distance, with the potential clinical implication that the CT in this clinical setting could be avoided.

Resumo Objetivo Comparar a ressonância magnética (RM) usando uma bobina corporal e tomografia computadorizada (TC) na medição da distância tubérculo tibial-sulco troclear (TT-ST) e as distâncias tendão patelar-sulco troclear cartilaginoso (TP-STC), e avaliar a confiabilidade interavaliador. Métodos O grupo de estudo consistiu em 34 joelhos de 17 indivíduos assintomáticos sem história de patologia, trauma ou cirurgia no joelho. Uma tomografia computadorizada (TC) de baixa dose e uma sequência axial de RM ponderada em T1 dos joelhos foram realizadas com padronização rigorosa do posicionamento com extensão total dos joelhos e pés paralelos. Dois radiologistas musculoesqueléticos realizaram as medidas de forma independente. A confiabilidade das distâncias TT-ST e TP-STC na TC (17,1 ± 4,2 mm e 17,3 ± 4,2 mm) e RM (16,2 ± 3,7 mm e 16,5 ± 4,1 mm), foi avaliada pelo coeficiente de correlação intraclasse (CCI [2,1)]) e gráficos Bland-Altman, bem como a confiabilidade entre avaliadores para ambos os métodos. Resultados Boa confiabilidade e concordância foram observadas entre as medidas de TC e RM para TT-ST e TP-STC com um CCI de 0,774 (p< 0,001) e 0,743 (p< 0,001), respectivamente, e nenhum viés sistemático foi observado. A confiabilidade entre avaliadores foi excelente para todas as medições em ambos os métodos de imagem. Conclusão Este foi o primeiro estudo que comparou a RM usando bobina de corpo com a TC na medição da distância TT-ST, com a implicação clínica potencial de que a TC neste cenário clínico poderia ser evitada.

Osteochondral lesions of the talar dome: an up-to-date approach to multimodality imaging and surgical techniques.

Osteochondral lesions (OCLs) of the talar dome consist of a multifactorial pathology of the articular cartilage and subchondral bone and can result in persistent ankle pain and osteoarthritis (OA). Along with a physical examination and clinical history, an imaging evaluation plays a pivotal role in the diagnosis of these lesions and is fundamental for making treatment decisions and determining prognosis by providing information regarding the size, location, and cartilage and subchondral bone statuses as well as associated lesions and degenerative changes. Multiple surgical techniques for OCLs of the talar dome have been developed in recent decades, including cartilage repair, regeneration, and replacement strategies, and radiologists should be acquainted with their specific expected and abnormal postoperative imaging findings to better monitor the results and predict poor outcomes. The present article proposes a thorough review of the ankle joint anatomy and biomechanics, physiopathology, diagnosis, and treatment of OCLs of the talar dome, highlighting the radiological approach and imaging findings in both pre- and postoperative scenarios.

The Role of Whole-Body MRI in Pediatric Musculoskeletal Oncology: Current Concepts and Clinical Applications.

Whole-body magnetic resonance imaging (WB-MRI) has gained importance in the field of musculoskeletal oncology over the last decades, consisting in a one-stop imaging method that allows a wide coverage assessment of both bone and soft tissue involvement. WB-MRI is valuable for diagnosis, staging, and follow-up in many oncologic diseases and is especially advantageous for the pediatric population since it avoids redundant examinations and exposure to ionizing radiation in patients who often undergo long-term surveillance. Its clinical application has been studied in many pediatric neoplasms, such as cancer predisposition syndromes, Langerhans cell histiocytosis, lymphoma, sarcomas, and neuroblastoma. The addition of diffusion-weighted sequences allows functional evaluation of neoplastic lesions, which is helpful in the assessment of viable tumor and response to treatment after neoadjuvant or adjuvant therapy. WB-MRI is an excellent alternative to fluorodeoxyglucose-positron emission tomography/computed tomography in oncologic children, with comparable accuracy and the convenience of being radiation-free, fast to perform, and available at a similar cost. The development of new techniques and protocols makes WB-MRI increasingly faster, safer, and more accessible, and it is important for referring physicians and radiologists to recognize the role of this imaging method in pediatric oncology. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY STAGE: 2.

The Role of Magnetic Resonance in the Diagnosis of Chronic Exertional Compartment Syndrome.

Chronic compartment syndrome is a common and often underdiagnosed exercise-induced condition, accounting on average for a quarter of cases of chronic exertional pain in the leg, second only to the fracture/tibial stress syndrome spectrum. It traditionally occurs in young runner athletes, although more recent studies have demonstrated a considerable prevalence in low-performance practitioners of physical activity, even in middle-aged or elderly patients. The list of differential diagnoses is extensive, and sometimes it is difficult to distinguish them only by the clinical data, and subsidiary examinations are required. The diagnosis is classically made by the clinical picture, by exclusion of the differential diagnoses, and through the measurement of the intracompartmental pressure. Although needle manometry is considered the gold standard in the diagnosis, its use is not universally accepted, since there are some important limitations, apart from the restricted availability of the needle equipment in Brazil. New protocols of manometry have recently been proposed to overcome the deficiency of the traditional ones, and some of them recommend the systematic use of magnetic resonance imaging (MRI) in the exclusion of differential diagnoses. The use of post-effort liquid-sensitive MRI sequences is a good noninvasive option instead of needle manometry in the diagnosis of chronic compartment syndrome, since the increase in post-exercise signal intensity is statistically significant when compared with manometry pressure values in asymptomatic patients and in those with the syndrome; hence, the test can be used in the diagnostic criteria. The definitive treatment is fasciotomy, although there are less effective alternatives.

The Role of Magnetic Resonance in the Diagnosis of Chronic Exertional Compartment Syndrome / O papel da ressonância magnética no diagnóstico da síndrome compartimental crônica do exercício

Abstract Chronic compartment syndrome is a common and often underdiagnosed exercise-induced condition, accounting on average for a quarter of cases of chronic exertional pain in the leg, second only to the fracture/tibial stress syndrome spectrum. It traditionally occurs in young runner athletes, although more recent studies have demonstrated a considerable prevalence in low-performance practitioners of physical activity, even in middle-aged or elderly patients. The list of differential diagnoses is extensive, and sometimes it is difficult to distinguish them only by the clinical data, and subsidiary examinations are required. The diagnosis is classically made by the clinical picture, by exclusion of the differential diagnoses, and through the measurement of the intracompartmental pressure. Although needle manometry is considered the gold standard in the diagnosis, its use is not universally accepted, since there are some important limitations, apart from the restricted availability of the needle equipment in Brazil. New protocols of manometry have recently been proposed to overcome the deficiency of the traditional ones, and some of them recommend the systematic use of magnetic resonance imaging (MRI) in the exclusion of differential diagnoses. The use of post-effort liquid-sensitive MRI sequences is a good noninvasive option instead of needle manometry in the diagnosis of chronic compartment syndrome, since the increase in post-exercise signal intensity is statistically significant when compared with manometry pressure values in asymptomatic patients and in those with the syndrome; hence, the test can be used in the diagnostic criteria. The definitive treatment is fasciotomy, although there are less effective alternatives.

Resumo A síndrome compartimental crônica é uma condição comum e frequentemente subdiagnosticada, induzida pelo exercício, que corresponde em média a um quarto dos casos de dor crônica na perna relacionada ao exercício, e que perde em frequência apenas para o espectro fratura/reação ao estresse tibial. Tradicionalmente ocorre em jovens atletas corredores, embora estudos mais recentes tenham demonstrado uma prevalência considerável em praticantes de atividade física de baixo rendimento, mesmo em pacientes de meia-idade ou idosos. A lista de diagnósticos diferenciais é extensa, e por vezes é difícil fazer a distinção apenas pelos dados clínicos, sendo necessários exames subsidiários. Classicamente, o diagnóstico é feito pelo quadro clínico, pela exclusão dos diferenciais, e pela medida pressórica intracompartimental. Embora a manometria por agulha seja considerada o padrão-ouro no diagnóstico, seu uso não é universalmente aceito, visto que existem algumas limitações importantes, além da disponibilidade restrita do equipamento com agulha no Brasil. Recentemente, novos protocolos de manometria têm sido propostos a fim suplantar a deficiência dos tradicionais, com algum deles inclusive recomendando o uso sistemático da ressonância magnética (RM) na exclusão dos diagnósticos diferenciais. O uso de sequências de RM sensíveis a líquido pós-esforço é uma ótima opção não invasiva à manometria por agulha no diagnóstico da síndrome compartimental crônica, uma vez que o aumento da intensidade de sinal pós-exercício é estatisticamente relevante quando comparados os valores pressóricos de manometria em pacientes com a síndrome e assintomáticos; portanto, o exame pode ser usado no critério diagnóstico. O tratamento definitivo é a fasciotomia, embora existam alternativas menos eficazes.

Coccigodínias: diagnóstico por imagem / Coccygodynia: diagnostic imaging

Coccigodínia é uma síndrome dolorosa de difícil abordagem diagnóstica e terapêutica, ainda mal compreendida por clínicos, ortopedistas e radiologistas. No intuito de entender e diferenciar as anormalidades clínico-radiológicas encontradas nas coccigodínias, revisamos a anatomia normal do sacro-cóccix e das demais estruturas pélvicas, suas variações e alterações anatômicas, além doselementos biomecânicos e fisiopatológicos implicados na etiologia da dor. O estudo radiológico funcional do cóccix consiste na obtenção de incidências de perfil nas posições ortostática e sentada, que permite a determinação da mobilidade coccígea. Este método pode demonstrar lesãocausal em 70% dos casos de coccigodínia. A classificação radiológica segundo as alterações da dinâmica do cóccix pode orientar tratamentos e comparar respostas terapêuticas por subgrupos.

Coccygodynia is a painful syndrome still misunderstood by physicians. To understand the radiological abnormalities that may accompanythis syndrome we have revised sacro-coccygeal normal anatomy and its variants and biomechanical elements that may produce pain. Functional radiologic studies of the coccyx consistin lateral projection in upright and sitted positions. Such projections provide clues for the evaluation of coccygeal mobility and may disclose the causal lesion producing coccygodynia in about 70%of the patients. Radiologic classification of the dynamic dysfunctions of coccygeal mobility may orient treatments and compare outcomes in subgroups.