Involvement of the bone marrow by metastases from solid tumors or multiple myeloma (MM) is a critical challenge in oncologic imaging. Lesion detection and staging, as well as accurate assessment of treatment response, disease recurrence, and complications, are key to optimal patient management. This article provides recommendations for performing and interpreting bone marrow MRI in cancer patients. MRI should be the primary imaging modality for patients suspected of having skeletal bone metastases or MM, and should replace radiography, bone scintigraphy, and CT for these indications. Protocols must be tailored to the clinical context and to each specific cancer. Whole-body MRI (WB-MRI) is preferred for a comprehensive assessment, while axial skeleton MRI (AS-MRI) is a fast and reliable alternative for targeted or follow-up evaluations. We recommend standardized protocols that incorporate anatomical sequences (preferably fast spin echo T2 Dixon) and diffusion-weighted imaging (DWI). Quantitative biomarkers, e.g., apparent diffusion coefficient (ADC) and fat fraction (FF), should be implemented to improve diagnostic accuracy and evaluate treatment response. Radiologists must be familiar with the typical patterns of bone marrow replacement by cancer cells, response assessment principles, and common imaging pitfalls. Every medical imaging facility should offer optimal bone marrow MRI and implement these recommendations using available MRI systems and existing disease-oriented guidelines. This ESR Essentials illustrates when, how, and why to perform bone marrow MRI to improve diagnostic precision and oncologic care across a broad range of indications.

Teaching point: The clues to the correct diagnosis of muscle sarcoidosis on MRI are the typical 'dark star' sign in the axial plane and the 'three‑stripe' sign in the longitudinal plane.

Teaching point: Differentiating diaphyseal osteomyelitis and bone infarction in patients with sickle cell disease is challenging and requires meticulous correlation of imaging and clinical findings.

Tophaceous gout of the patella and extensor apparatus of the knee can mimic a musculoskeletal neoplasm. Considering gout, correlation with clinical history and presentation, and meticulous analysis of imaging semiology are key to a correct diagnosis. The most useful signs are periarticular erosion with overhanging edges, increased soft tissue on radiography and computed tomography, the "snowstorm sign" on ultrasound, variable signal and enhancement, bandlike infiltration of tendons, and osseous erosions with no or little bone marrow edema on magnetic resonance imaging. Dual-energy computed tomography is both a sensitive and specific tool for noninvasive characterization of gout and for differentiating other crystal arthropathies.

This chapter deals with the general principles of posttreatment imaging of tumors of the osseous spine. Prerequisites for post-therapeutic imaging include clinical presentation and familiarity with the tumor histology, surgical technique, previous radio- or chemotherapy, and access to the preoperative imaging. The recommended time interval for local and distant posttreatment imaging depends on the tumor histology. MRI is the preferred technique for local surveillance and should include conventional MRI, diffusion-weighted imaging, and dynamic contrast-enhanced imaging. In the presence of metal implants, the imaging parameters should be adjusted.

This history page is dedicated to the memory and achievements of the French rheumatologist Stanislas de Sèze whose name is connected to the so-called de Sèze view, used to evaluate the sacroiliac joints, the lumbar and lower thoracic spine, pelvis, and hip joints on a single anteroposterior radiograph.

Teaching point: The clues to the correct diagnosis of heterotopic ossification of the indirect head of the rectus femoris are its location above the acetabular rim and its (inverted) comma‑like morphology.

As per recommendations from the European Society of Radiology and the European Union of Medical Specialists, upon completion of level 3 radiology training, an objective assessment of the attained standards, aligned with national customs and practices, should take place. A subspecialty exam should ideally be an integral part of the training completion process. Among 10 of 13 European subspecialty societies currently offering a European subspecialty diploma, the European Society of Musculoskeletal Radiology (ESSR) diploma program was formally introduced by the ESSR in 2003. This article describes the evolution of the ESSR diploma, encompassing the current diploma program, validation procedures, endorsements, and future perspectives. Additionally, insights from a brief survey among ESSR diploma holders is shared, offering valuable tips for prospective candidates aiming to navigate the examination process successfully.

Purpose: The aim of this study was to investigate if ultrasound could be a reliable and accurate tool to measure the size of the peroneal tubercle. Material and methods: This study measured the width, length, and height of the peroneal tubercle in 100 asymptomatic patients, comparing the measurements to prior radiographs of the foot (if available) and previously reported anatomical data. This study also assessed the intra- and interrater reliability of ultrasound as a measurement tool. Results: Our findings show that ultrasound measurements of the peroneal tubercle were consistent with values reported in the literature and prior radiographs concerning width. Both intra- and inter -observer measurements were reliable. Conclusions: This study highlights the potential of ultrasound imaging as a promising tool to measure the peroneal tubercle, and it could contribute to a better understanding of peroneal tendon disorders.

The European Diploma in Musculoskeletal Radiology (EDiMSK) is a recognized European qualification of excellence for musculoskeletal (MSK) radiologists. The EDiMSK confirms proof of knowledge of MSK radiology in addition to any national qualifications certifying competency. The examination is conducted in English and consists of both a written and an oral part. This article guides candidates taking the EDiMSK examination on how to prepare for the oral exam that consists of clinical cases. Information is provided on how the clinical cases are structured and how the candidate is scored. Ten cases representative of the oral section of the EDiMSK are also presented.

Teaching point: Magnetic resonance imaging (MRI) and ultrasound may be useful to assess the extent of onychodystrophy associated with psoriatic dactylitis by showing nail bed thickening, matrix changes, and vascularity indicative of active inflammation.

Teaching point: Benign hyperostosis of the rib is a benign entity consisting of a stress phenomenon that should not be confused with Paget, fibrous dysplasia, or osteoblastic metastasis.

This history page is dedicated to the memory and achievements of the pediatric radiologist Hooshang Taybi whose name is associated with the Rubinstein-Taybi syndrome, Taybi syndrome, and Taybi-Linder syndrome.

Teaching point: Melorheostosis is a rare sclerosing bone dysplasia, characterized by sclerosis at the periosteal and/or endosteal side of the cortex, causing undulating thickening of the bony contour resembling "dripping candle wax."

The revised European Society of Musculoskeletal Radiology (ESSR) consensus guidelines on soft tissue tumor imaging represent an update of 2015 after technical advancements, further insights into specific entities, and revised World Health Organization (2020) and AJCC (2017) classifications. This second of three papers covers algorithms once histology is confirmed: (1) standardized whole-body staging, (2) special algorithms for non-malignant entities, and (3) multiplicity, genetic tumor syndromes, and pitfalls. A validated Delphi method based on peer-reviewed literature was used to derive consensus among a panel of 46 specialized musculoskeletal radiologists from 12 European countries. Statements that had undergone interdisciplinary revision were scored online by the level of agreement (0 to 10) during two iterative rounds, that could result in ‘group consensus’, ‘group agreement’, or ‘lack of agreement’. The three sections contain 24 statements with comments. Group consensus was reached in 95.8

Tuberculosis (TB) represents a major public health problem worldwide. Any tissue may be infected. Involvement of the musculoskeletal (MSK) system account for 1-3% of all tuberculous infections. MSK TB may manifest as tuberculous spondylitis, arthritis, osteomyelitis, and soft tissue infections. Although TB spondylitis may present with distinctive imaging features compared to pyogenic infections of the spine, the imaging semiology of extra-spinal TB infections is mostly nonspecific and may mimic other lesions. TB infections should therefore always be considered in the differential diagnosis, particularly in immunocompromised patients. The aim of this article is to review the imaging features of spinal and extra-spinal MSK TB. Magnetic resonance imaging is considered the modality of choice to make the diagnosis and to evaluate the extent of the disease.

Teaching point: Extradigital glomus tumor should be considered in the differential diagnosis of a highly vascular solid lesion that is painful on palpation.

An update of the first European Society of Musculoskeletal Radiology (ESSR) consensus on soft tissue tumor imaging in 2015 became necessary due to technical advancements, further insights into specific entities, and the revised WHO classification (2020) and AJCC staging system (2017). The third part of the revised guidelines covers algorithms and techniques beyond initial imaging: (1) Imaging after neoadjuvant therapy in soft tissue sarcoma, (2) sarcoma surveillance, and (3) special aspects, including surveillance of non-malignant entities and the role of interventional radiology. A validated Delphi method based on peer-reviewed literature was used to derive consensus among a panel of 46 specialized musculoskeletal radiologists from 12 European countries. Statements that had undergone interdisciplinary revision were scored online by level of agreement (0 to 10) during two iterative rounds that could result in either ‘group consensus,’ ‘group agreement,’ or ‘lack of agreement.’ The three sections contain 47 statements with comments. Group consensus was reached in 91.5

The European Diploma in Musculoskeletal Radiology (EDiMSK) is a recognized European qualification of excellence for musculoskeletal (MSK) radiologists. Webinars have become a vital component of electronic learning. This article introduces European Society of Musculoskeletal Radiology members to its webinar program that offers an additional source of direct interactive learning from renowned MSK radiologists. These webinars contribute to Continuing Medical Education and assist in preparing for the EDiMSK exam. We discuss the concept, history, and organization of the webinars.