Radiologic evaluation of musculoskeletal soft-tissue masses has changed dramatically with the continued improvements in imaging technology. The integration of advanced imaging has provided the ...radiologist with a wide range of assessment tools, but as with all powerful arsenals, selection and application of the appropriate imaging method can be problematic. Although the choices available for imaging evaluation of musculoskeletal masses have changed dramatically, the basic objectives of this assessment have remained constant: diagnosis and staging. The basic principles for evaluating musculoskeletal soft-tissue masses and achieving these objectives have not changed. This article addresses application of the current imaging methods to assessment of soft-tissue musculoskeletal masses, emphasizing fundamental concepts. We do not intend to provide a comprehensive review of imaging techniques, but rather to provide a useful review of the concepts needed to select the appropriate initial imaging method, magnetic resonance (MR) imaging field of view, MR imaging sequences, contrast material requirements, and rapid image acquisition techniques. We also address use of the new quantitative techniques of chemical shift and diffusion-weighted imaging. Finally, we review the current uses of computed tomography and ultrasonography. Although the choices available for imaging evaluation of musculoskeletal masses have changed dramatically within the past decade, appropriate application of the fundamental concepts of imaging will maximize the diagnostic utility of imaging examinations.
RSNA, 2016.
The Ewing sarcoma family of tumors includes osseous Ewing sarcoma, extraskeletal Ewing sarcoma, primitive neuroectodermal tumor, and Askin tumor. They share a karyotype abnormality with translocation ...involving chromosomes 11 and 22. Histologically, these lesions demonstrate crowded sheets of small round blue cells. Imaging features of osseous Ewing sarcoma often suggest the diagnosis, with aggressive long-bone destruction in the metadiaphysis of an adolescent or young adult and an associated soft-tissue mass. Focal areas of cortical destruction are frequent, allowing continuity between the intraosseous and extraosseous components. This continuity is also commonly seen as subtle channels extending through the cortex at computed tomography or magnetic resonance (MR) imaging, a finding that reflects the underlying pathologic appearance. Extraskeletal Ewing sarcoma commonly demonstrates a nonspecific radiologic appearance of a large soft-tissue mass affecting the paraspinal region or lower extremity. Askin tumor represents extraskeletal Ewing sarcoma involving the chest wall. Imaging typically reveals a large pleural-based mass and associated pleural effusion. Treatment of these tumors is usually a combination of neoadjuvant chemotherapy followed by surgical resection, which may be supplemented with radiation therapy. Imaging, particularly MR, is also vital to evaluate response to neoadjuvant therapy, direct surgical resection, and detect local recurrence or metastatic disease.
Osteonecrosis is common and represents loss of blood supply to a region of bone. Common sites affected include the femoral head, humeral head, knee, femoral/tibial metadiaphysis, scaphoid, lunate, ...and talus. Symptomatic femoral head osteonecrosis accounts for 10,000-20,000 new cases annually in the United States. In contradistinction, metadiaphyseal osteonecrosis is often occult and asymptomatic. There are numerous causes of osteonecrosis most commonly related to trauma, corticosteroids, and idiopathic. Imaging of osteonecrosis is frequently diagnostic with a serpentine rim of sclerosis on radiographs, photopenia in early disease at bone scintigraphy, and maintained yellow marrow at MR imaging with a serpentine rim of high signal intensity (double-line sign) on images obtained with long repetition time sequences. These radiologic features correspond to the underlying pathology of osseous response to wall off the osteonecrotic process and attempts at repair with vascularized granulation tissue at the reactive interface. The long-term clinical importance of epiphyseal osteonecrosis is almost exclusively based on the likelihood of overlying articular collapse. MR imaging is generally considered the most sensitive and specific imaging modality both for early diagnosis and identifying features that increase the possibility of this complication. Treatment subsequent to articular collapse and development of secondary osteoarthritis typically requires reconstructive surgery. Malignant transformation of osteonecrosis is rare and almost exclusively associated with metadiaphyseal lesions. Imaging features of this dire sequela include aggressive bone destruction about the lesion margin, cortical involvement, and an associated soft-tissue mass. Recognizing the appearance of osteonecrosis, which reflects the underlying pathology, improves radiologic assessment and is important to guide optimal patient management.
Objective
To determine the preferred ankle, knee, and elbow arthrography injection techniques for Society of Skeletal Radiology (SSR) members and whether more recently described techniques are ...gaining acceptance. We also sought to determine whether the concept of knowledge translation might explain differences between the preferred technique, year of fellowship graduation, and year the newer technique was described.
Materials and methods
A 29-question survey was created in Qualtrics and submitted to current SSR members to determine if they perform knee, elbow, and ankle arthrography, and if so, the year of fellowship completion and preferred approaches. Survey respondents indicated the starting and ending needle tip positions for three knee, two elbow, and three ankle arthrography approaches using grids placed over provided frontal and lateral radiographs.
Results
Two hundred seventy-four SSR members (mean post-fellowship 13 years; range 0–38) completed the survey and performed fluoroscopic-guided knee (93%), elbow (95%), and ankle (75%) arthrography. Preferred approaches included the following: knee lateral subpatellar (43%), anterior (40%); elbow radiocapitellar (74%); ankle anterior/peritendon (70%), lateral mortise (24%). Preference of newer technique was related to fellowship graduation year and publication year for the ankle mortise (26% before, 42% after;
p
= 0.03) and posterior trans-triceps elbow articles (19% before, 33% after;
p
< 0.01). The anterior knee approach preference increased from 11% in 2008 to 40% (
p
≤ 0.001).
Conclusion
Nearly twice as many SSR members who graduated after the posterior trans-triceps and ankle mortise techniques were published prefer them for performing arthrography, possibly due to knowledge translation. The preference of the anterior knee arthrography approach has increased nearly fourfold since 2008.
To validate a technique for reproducible measurement of the osteochondroma cartilage cap with computed tomography (CT) and magnetic resonance (MR) imaging and to reevaluate the correlation of the ...thickness of the cartilage cap with pathologic findings to improve noninvasive differentiation of benign osteochondromas from secondary chondrosarcomas.
The institutional review board approved the study and waived the need for informed consent. HIPAA compliance was maintained. After validation of the measurement technique, 101 pathologically confirmed osteochondromas were retrospectively reviewed. Patient demographic data, histologic diagnosis, and chondrosarcoma grade were recorded. Two musculoskeletal radiologists used a standardized technique to independently measure the thicknesses of the cartilage caps on CT and MR images; these measurements were compared for interobserver agreement. Agreement between measurements with CT and MR imaging was also evaluated, as were the sensitivity and specificity of both modalities for differentiation of osteochondromas from chondrosarcomas.
Evaluated were 67 benign osteochondromas (from 49 male patients and 18 female patients; mean age, 23.4 years) and 34 secondary chondrosarcomas (from 27 male patients and seven female patients; mean age, 33.2 years). On the basis of the proposed measuring technique, there was 88% interobserver measurement agreement with MR imaging (95% confidence interval CI: 80%, 94%) and 93% with CT (95% CI: 84%, 98%). The median difference between measurements of cap thickness at CT and MR imaging was 0 cm (25th and 75th percentiles, -3 mm and 1 mm, respectively). With 2 cm used as a cutoff for distinguishing benign osteochondromas from chondrosarcomas, the sensitivities and specificities were 100% and 98% for MR imaging and 100% and 95% for CT, respectively.
The proposed measuring technique allows accurate and reproducible measurement of cartilage cap thickness with both CT and MR imaging. Cap thickness of 2 cm or greater strongly indicated secondary chondrosarcomas.
Lodwick's well-established grading system of lytic bone lesions has been widely used in predicting growth rate for lytic bone lesions. We applied a Modified Lodwick-Madewell Grading System as an ...alternative means to categorize lytic bone tumors into those with low, moderate, and high risks of malignancy.
A retrospective review of the radiographs of 183 bone lesions was performed. Cases were selected to include a broad range of benign and malignant tumors. Readers applied our Modified Lodwick-Madewell Grading System, and consensus was reached in all cases. This modified system consists of grade I, which is composed of grades IA and IB as listed in the Lodwick system; grade II, which is grade IC in the Lodwick system; and grade III, which is composed of IIIA (changing margination), IIB (moth-eaten and permeative patterns), and IIIC (radiographically occult). Grading was correlated with the final diagnosis.
Of the 183 tumors, 81 were classified as grade I, 54 as grade II, and 48 as grade III. When correlating grade with pathology, we found that 76 of 81 (94%) grade I lesions were benign and 39 of 48 grade III lesions (81%) were malignant. A nearly equal number of grade II lesions proved to be benign (29/54; 54%) and malignant (28/54; 53%).
By expanding Lodwick's grading system to include two additional patterns of disease described by Madewell and colleagues (changing margination and radiographically occult) and by reclassifying them into three distinct grades, we propose a modified system-the Modified Lodwick-Madewell Grading System. Application of this system shows correlation of tumor grade with tumor biologic activity and with risk of malignancy: Grade I lesions are usually benign, grade II lesions carry moderate risk of malignancy, and grade III lesions possess a high likelihood of malignancy.
Primary Musculoskeletal Lymphoma Murphey, Mark D; Kransdorf, Mark J
The Radiologic clinics of North America,
07/2016, Volume:
54, Issue:
4
Journal Article
Peer reviewed
Primary lymphoma of bone and soft tissue is rare and almost invariably of B-cell origin. Osseous lymphoma usually reveals aggressive bone destruction and associated soft tissue extension. Soft tissue ...involvement is optimally depicted by MR imaging. Cortical destruction allowing communication between the intraosseous and soft tissue components may be subtle with small striations of extension. Lymphoma of the deep soft tissues usually reveals long cones of intramuscular or intermuscular tumor again best depicted by MR imaging. Cutaneous or subcutaneous lymphoma demonstrates multiple nodules and plaquelike thickening.
To review the reliability of computed tomographic (CT) and magnetic resonance (MR) imaging features in distinguishing lipoma and well-differentiated liposarcoma.
CT (n= 29) and MR (n = 40) images and ...radiographs (n = 28) of 60 patients with histologically verified fatty tumors (35 lipomas and 25 well-differentiated liposarcomas) were retrospectively reviewed in 31 females and 29 males (mean age, 56 years; age range, 1-88 years). Images were assessed for adipose tissue content, and non-fatty component was classified (thin and/or thick septa and nodular and/or globular components) as absent, mild, moderate, or pronounced. Also assessed were signal intensity and tissue attenuation of the fatty components and non-adipose elements.
Statistically significant imaging features favoring a diagnosis of liposarcoma included lesion larger than 10 cm (P <.001), presence of thick septa (P =.001), presence of globular and/or nodular non-adipose areas (P =.003) or masses (P =.001), and lesion less than 75% fat (P <.001). The most statistically significant radiologic predictors of malignancy were male sex, presence of thick septa, and associated non-adipose masses, which increased the likelihood of malignancy by 13-, nine-, and 32-fold, respectively. Both lipoma and liposarcoma demonstrated thin septa and regions of increased signal intensity on fluid-sensitive MR images.
A significant number of lipomas will have prominent non-adipose areas and will demonstrate an imaging appearance traditionally ascribed to well-differentiated liposarcoma. Features that suggest malignancy include increased patient age, large lesion size, presence of thick septa, presence of nodular and/or globular or non-adipose mass-like areas, and decreased percentage of fat composition.
PDF
