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PURPOSE Benign, intermediate-grade and malignant tumors sometimes have overlapping imaging and clinical characteristics. The purpose of this study was to evaluate the added value of contrast-enhanced sequences (dynamic contrast enhancement (DCE)), diffusion-weighted imaging (DWI), and chemical shift imaging (CSI) to noncontrast MRI sequences for the characterization of indeterminate lipomatous tumors. MATERIALS AND METHODS Thirty-two consecutive patients with histologically proven peripheral lipomatous tumors were retrospectively evaluated. Two musculoskeletal radiologists recorded the MRI features in three sessions: (1) with noncontrast T1-weighted and fluid-sensitive sequences; (2) with addition of static pre- and post-contrast 3D volumetric T1-weighted sequences; and (3) with addition of DCE, DWI, and CSI. After each session, readers recorded a diagnosis (benign, intermediate/atypical lipomatous tumor (ALT), or malignant/dedifferentiated liposarcoma (DDL)). Categorical imaging features (presence of septations, nodules, contrast enhancement) and quantitative metrics (apparent diffusion coefficient values, CSI signal loss) were recorded. RESULTS For 32 tumors, the diagnostic accuracy of both readers did not improve with the addition of contrast-enhanced sequences, DWI, or CSI (53% (17/32) session 1; 50% (16/30) session 2; 53% (17/32) session 3). Noncontrast features, including thick septations (p = 0.025) and nodules ≥ 1 cm (p

Advances in the understanding and treatment of multiple myeloma have led to the need for more sensitive and accurate imaging of intramedullary and extramedullary disease. This role of imaging is un...

ObjectiveTo assess imaging utilization practices across clinical specialists in neurofibromatosis type 1 (NF1) for the evaluation of symptomatic and asymptomatic children and adults with or without plexiform neurofibromas (PN).MethodsAn institutional review board–exempt survey was administered to medical practitioners caring for individuals with NF1 at the Response Evaluation in Neurofibromatosis and Schwannomatosis (REiNS) meeting in September 2019. The survey included questions on respondent demographic data (9 questions), type of imaging obtained for asymptomatic (4 questions) and symptomatic (4 questions) people with and without PN, and utilization of diffusion-weighted imaging (2 questions).ResultsThirty practitioners participated in the survey. Most were academic neuro-oncologists at high-volume (>10 patients/week) NF1 centers. Of 30 respondents, 26 had access to whole-body MRI (WB-MRI). The most common approach to an asymptomatic person without PN was no imaging (adults: 57% [17/30]; children: 50% [15/30]), followed by a screening WB-MRI (adults: 20% [6/30]; children: 26.7% [8/30]). The most common approach to a person with symptoms or known PN was regional MRI (adults: 90% [27/30]; children: 93% [28/30]), followed by WB-MRI (adults: 20% [6/30]; children: 36.7% [11/30]). WB-MRI was most often obtained to evaluate a symptomatic child with PN (37% [11/30]).ConclusionsMore than 90% of practitioners indicated they would obtain a regional MRI in a symptomatic patient without known or visible PN. Otherwise, there was little consensus on imaging practices. Given the high prevalence of PN and risk of malignant conversion in this patient population, there is a need to define imaging-based guidelines for optimal clinical care and the design of future clinical trials.

Advances in magnetic resonance imaging (MRI) technology now enable the feasible three-dimensional (3D) acquisition of images. With respect to the imaging of musculoskeletal (MSK) tumors, literature is beginning to accumulate on the use of 3D MRI acquisition for tumor detection and characterization. The benefits of 3D MRI, including general advantages, such as decreased acquisition time, isotropic resolution, and increased image quality, are not only inherently useful for tumor imaging, but they also contribute to the feasibility of more specialized tumor-imaging techniques, such as whole-body MRI, and are reviewed here. Disadvantages of 3D acquisition, such as motion artifact and equipment requirements, do exist and are also discussed. Although further study is needed, 3D MRI acquisition will likely prove increasingly useful in the evaluation of patients with tumors of the MSK system.

The anatomic extent of a pelvic bone tumor and the need for reconstruction dictate the type of pelvic resection (limb salvage pelvic resection or amputation). If a pelvic bone tumor resection involves two or more critical anatomic structures (the sciatic nerve, femoral neurovascular bundle or the hip joint), then reasonable functional recovery after limb salvage is less likely and amputation should be considered. Both limb salvage and amputation approaches to the pelvis are technically arduous surgeries with significant associated morbidity and complications. As such, imaging plays an important role in the post-operative management of patients who have undergone pelvic bone tumor resection. In this article, we will review optimal imaging techniques as well as the expected post-operative appearance after pelvic bone tumor resection and important complications including infection, tumor recurrence, and complications related to complex soft tissue and osseous reconstruction.

To test the hypothesis that an accelerated, T1-weighted 3D CAIPIRINHA SPACE sequence with isotropic voxel size offers a similar performance to conventional T1-weighted 2D TSE (turbo spin echo) for the evaluation of bone tumor extent and characteristics. Thirty-four patients who underwent 3-T MRI with 3DT1 (CAIPIRINHA SPACE TSE) and 2DT1 (TSE) were included. Sequence acquisition time was reported. Two radiologists independently evaluated each technique for tumor location, size/length, tumor-to-joint distance, signal intensity, margin/extraosseous extension, and signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. Tumors were located in long (20/36, 55.5%) and pelvic (16/36, 44.4%) bones. 3DT1 sequence required an average acquisition time of 235 s (± 42 s, range 156–372), while two plane 2DT1 sequences combined (coronal and axial) had an average acquisition time of 381 s (± 73 s, range 312–523). There was no difference in the measurements of tumor length and tumor-to-joint distance (p = 0.95) between 3DT1 and 2DT1 images. Tumors were hypointense (17/36, 47.2% vs 17/36, 47.2%), isointense (12/36, 33.3% vs 12/36, 33.3%), or hyperintense (7/36, 19.4% vs 7/36, 19.4%) on 3DT1 vs 2DT1, respectively. Assessment of tumor margins and extraosseous extension was similar, and there was no difference in tumor SNR or CNR (p > 0.05). An accelerated 3D CAIPIRINHA SPACE T1 sequence provides comparable assessments of intramedullary bone tumor extent and similar tumor characteristics to conventional 2DT1 MRI. For the assessment of bone tumors, the isotropic volume acquisition and multiplanar reformation capability of the 3DT1 datasets can obviate the need for 2DT1 acquisitions in multiple planes. • 3DT1 offers an equivalent performance to 2DT1 for the assessment of bone tumor characteristics, with faster and higher resolution capability, obviating the need for acquiring 2DT1 in multiple planes. • There was no difference in the measurements of tumor length and tumor-to-joint distance obtained on 3DT1 and 2DT1 images. • There was no difference in signal-to-noise ratio (SNR) or contrast-to-noise ratio (CNR) measures between 3DT1 and 2DT1.

To evaluate the prevalence, imaging appearance, and significance of popliteal lymph nodes (PLN) on magnetic resonance imaging (MRI) in patients with distal femoral or proximal tibial osteosarcoma (OS).This study included consecutive patients with OS presenting from May 2016 to March 2018. Inclusion criteria were patients with distal femoral or proximal tibial OS with MRI and pathology at our institution. On MRI, two radiologists recorded primary tumor features (size, location, signal, extra-compartmental extension), and PLN characteristics (mean size, presence/absence of fatty hilum, mineralization, PET/bone scintigraphy avidity, contrast enhancement, and diffusion restriction). Tumor histology, stage, and clinical follow-up were recorded. Descriptive statistics were provided.Sixteen patients with OS (age 20 ± 10 (range10-40) years, 10/16 male) were included. Although 81% (13/16) of the patients had PLNs at presentation (size range 0.3-3.6 cm), fewer patients had extra-compartmental spread: intra-articular extension 50% (8/16), skip lesions 19% (3/16), lung metastases 31% (5/16), and osseous metastases 12% (2/16). Four (25% (4/16)) patients had PLN ≥ 1 cm; two were histologically proven reactive. One was presumed metastatic due to rapid development, mineralization, and FDG-avidity on PET/CT. The other ≥ 1 cm PLNs along with all twelve (75% (12/16)) that were 1 cm in mean diameter were presumed non-metastatic with documented stability for at least 12 months of follow-up.PLNs are frequently visible on MRI in patients with OS but are rarely (prevalence = 6%) metastatic. Features on MRI which may suggest metastatic PLNs include large size 1 cm and loss of a fatty hilum.

Musculoskeletal imaging is mainly based on the subjective and qualitative analysis of imaging examinations. However, integration of quantitative assessment of imaging data could increase the value of imaging in both research and clinical practice. Some imaging modalities, such as perfusion magnetic resonance imaging (MRI), diffusion MRI, or T2 mapping, are intrinsically quantitative. But conventional morphological imaging can also be analyzed through the quantification of various parameters. The quantitative data retrieved from imaging examinations can serve as biomarkers and be used to support diagnosis, determine patient prognosis, or monitor therapy.We focus on the value, or clinical utility, of quantitative imaging in the musculoskeletal field. There is currently a trend to move from volume- to value-based payments. This review contains definitions and examines the role that quantitative imaging may play in the implementation of value-based health care. The influence of artificial intelligence on the value of quantitative musculoskeletal imaging is also discussed.

High-resolution isotropic volumetric three-dimensional (3D) magnetic resonance neurography (MRN) techniques enable multiplanar depiction of peripheral nerves. In addition, 3D MRN provides anatomical and functional tissue characterization of different disease conditions affecting the peripheral nerves. In this review article, we summarize clinically relevant technical considerations of 3D MRN image acquisition and review clinical applications of 3D MRN to assess peripheral nerve diseases, such as entrapments, trauma, inflammatory or infectious neuropathies, and neoplasms.

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.

Traumatic peripheral nerve injury occurs more frequently in the pediatric population than previously recognized. High-resolution magnetic resonance (MR) imaging in the form of MR neurography can serve as a powerful noninvasive tool for detecting and characterizing peripheral nerve injury in children. In this review article we briefly discuss optimal methods of MR neurography image acquisition, highlighting core MR sequences necessary to characterize peripheral nerve injury. In addition, we illustrate the MR neurography appearance of normal and abnormal peripheral nerves in children, with emphasis on commonly used Seddon and Sunderland classification schemes to characterize peripheral nerve injury severity. The primary and secondary features associated with peripheral nerve injury including skeletal muscle denervation are reviewed in addition to key distinctive features that can impact operative versus nonoperative management of children. We include a checklist approach to interpreting MR neurography for the assessment of peripheral nerve injury.

Aim There is controversy regarding the diagnosis and classification of vascular anomalies (VA). As torso and extremities are the second most common body part for presentation of VAs, musculoskeletal (MSK) radiologists play a central role in VA classification. The purpose of this study was to evaluate the awareness and clinical use of the International Society for the Study of Vascular Anomalies (ISSVA) classification by MSK radiologists. Materials and Methods A Web-based survey was designed and electronically sent to Society of Skeletal Radiology (SSR) members, with 3 questions on demographics and 7 questions on ISSVA classification use and knowledge. The Z-test for binomial proportions is used to assess for statistical significance between subgroups. Results The response rate was 12% (130 of 1091), comprised of 64% (83 of 130) academic and 36% (47 of 130) nonacademic MSK radiologists. VAs accounted for only a small (0%-5%) proportion of clinical practice in the majority 92% (119 of 130). Only 17% (22 of 130) of MSK radiologists used the ISSVA classification in practice. Of all respondents, 74% (94 of 127) considered hemangioma a type of vascular malformation (VM). There was no significant difference in the response characteristics between academic and nonacademic radiologists. A greater proportion of MSK radiologists with >5 years’ experience provided responses that were discordant with the ISSVA classification compared with less experienced radiologists (0-5 years) in diagnosing hemangiomas in adult patients (P = 0.02), and using the presence of phleboliths to diagnose hemangiomas (P = 0.004). Conclusion Our survey results indicate a lack of familiarity with the ISSVA classification by the MSK radiology community.

Case A 30-year-old man presented with progressive lower right extremity pain and swelling, initially diagnosed as a deep venous thrombosis. He returned 18 months later after 2 episodes of gross hemoptysis, with chest computed tomography angiography findings concerning for tumor thrombus in the left pulmonary artery. Subsequent advanced imaging showed a lesion arising from his right femoral vein, which open biopsy revealed to be a primary intravascular mesenchymal chondrosarcoma. He underwent medical therapy, with improvement of pain and swelling and successful return to work. Conclusion Mesenchymal chondrosarcoma is a rare pathology, and its intravascular origin makes this case extraordinarily uncommon.

Whole-body magnetic resonance imaging (WB-MRI) is gradually being integrated into clinical pathways for the detection, characterization, and staging of malignant tumors including those arising in the musculoskeletal (MSK) system. Although further developments and research are needed, it is now recognized that WB-MRI enables reliable, sensitive, and specific detection and quantification of disease burden, with clinical applications for a variety of disease types and a particular application for skeletal involvement. Advances in imaging techniques now allow the reliable incorporation of WB-MRI into clinical pathways, and guidelines recommending its use are emerging. This review assesses the benefits, clinical applications, limitations, and future capabilities of WB-MRI in the context of other next-generation imaging modalities, as a qualitative and quantitative tool for the detection and characterization of skeletal and soft tissue MSK malignancies.

Case A 78-year-old man was followed for an incidentally found, asymptomatic lesion in his right proximal femur that was unchanged radiographically for 11 years. He developed pain and was believed to have experienced a stress fracture through the lesion. The lesion was biopsied, showing a high-grade pleomorphic sarcoma with an underlying senescent intraosseous lipoma. He was ultimately treated with wide excision and reconstruction of the proximal femur. Conclusion This case highlights the importance of obtaining a tissue diagnosis for lesions that become symptomatic.

To evaluate the frequency, clinico-pathologic and imaging features of malignant tumors in peripheral nerves which are of non-neurogenic origin (non-neurogenic peripheral nerve malignancy—PNM). We retrospectively reviewed our pathology database for malignant peripheral nerve tumors from 07/2014–07/2019 and performed a systematic review. Exclusion criteria were malignant peripheral nerve sheath tumor (MPNST). Clinico-pathologic and imaging features, apparent diffusion coefficient (ADCmin), and standard uptake values (SUVmax) are reported. After exclusion of all neurogenic tumors (benign = 196, MPNST = 57), our search yielded 19 non-neurogenic PNMs (7%, n = 19/272), due to primary intraneural malignancy (16%, n = 3/19) and secondary perineural invasion from an adjacent malignancy (16%, n = 3/19) or metastatic disease (63%, n = 12/19). Non-neurogenic PNMs were located in the lumbosacral plexus/sciatic nerves (47%, n = 9/19), brachial plexus (32%, n = 6/19), femoral nerve (5%, n = 1/19), tibial nerve (5%, n = 1/19), ulnar nerve (5%, n = 1/19), and radial nerve (5%, n = 1/19). On MRI (n = 14/19), non-neurogenic PNM tended to be small (

Image-guided percutaneous needle biopsy has emerged as a safe, effective, and accurate tool for the diagnosis and subsequent treatment of musculoskeletal lesions. In this chapter, we will overview the significance, indications, techniques, and outcomes of such procedures, with emphasis on percutaneous biopsies performed under computed tomography and magnetic resonance imaging guidance.

Similarly to soft tissue tumours, the World Health Organisation (WHO) classification categorises bone tumours based on their similarity to normal adult tissue. The most recent WHO classification provides an updated classification scheme that integrates the biological behaviour of bone tumours, particularly cartilage-forming tumours, and tumours are now further subdivided as benign, intermediate (locally aggressive or rarely metastasising), and malignant. Radiologists play an important role in the detection and initial characterisation of bone tumours, with careful analysis of their matrix mineralisation, location, and overall anatomic extent including extra-compartmental extension and neurovascular invasion. Radiography remains central to the detection and characterisation of bone tumours; however, magnetic resonance imaging (MRI) is the ideal modality for local staging. This review will discuss the most recent updates to the WHO classification of bone tumours that are relevant to radiologists in routine clinical practice. The utility of advanced MRI sequences such as diffusion-weighted imaging, dynamic contrast enhanced sequences, and magnetic resonance spectroscopy that may provide insight into the biological behaviour of various bone tumours is highlighted.

A 70-year-old man with a history of bladder and colon cancer presented with an enlarging mass in his right lower extremity. Forty years before presentation, he had injured his right lower extremity in a motor vehicle accident. Imaging findings indicated suspected sarcoma, which led to biopsy. Biopsy and further surgical exploration revealed the presence of a surgical sponge and surrounding local inflammatory reaction. No neoplasm was found, and the sponge and involved tissues were removed. Gossypiboma is exceedingly rare in the extremities. Imaging of retained foreign material can appear suggestive of sarcoma because of strong inflammatory responses and local tissue mass-like derangement resulting in heterogeneous signal changes. Ultimately, biopsy must be performed to ensure that no oncological pathological condition is present.

Bizarre parosteal osteochondromatous proliferation (BPOP) is a benign bone and cartilage forming tumor occurring on the surface of bones, predominantly on the hands and feet. A defining feature of BPOP is the purplish-blue mineralization of cartilaginous tissue, known as 'blue bone.' Here, we report on an institutional series of 16 cases of BPOP, including radiographic, histologic, and histomorphometric features. All tumors were composed of some element of bone, cartilage, fibrous tissue and 'blue bone,' though the amount of each tissue sub-type varied widely. Some cases showed focal 'blue bone' only, however this was a defining feature in all cases.

Digital nerves are intrinsic to the sensory and motor function of the hand. These nerves represent the terminal ramifications of the ulnar, median, and radial nerves and are located distal to the carpal tunnel and Guyon canal. With magnetic resonance imaging, traumatic and nontraumatic abnormalities of the digital nerves can be shown with high contrast as well as high spatial resolution. Digital nerve abnormalities are most commonly posttraumatic in nature; however, infection, inflammatory, vascular malformations, and neoplasms can rarely occur. Magnetic resonance imaging is playing an increasing role in the assessment of peripheral nerve injury throughout the body, and in the hand, which can accurately identify the extent and character of digital nerve abnormalities before operative intervention.

OBJECTIVE This study aimed to investigate the diagnostic accuracy of magnetic resonance (MR) imaging for categorizing sciatic peripheral nerve injury (PNI) as high-grade (Sunderland grades IV-V) or low-grade (Sunderland grades I-III) PNI. METHODS In this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study, consecutive MR imaging of the pelvis and thighs, performed for the evaluation of traumatic sciatic neuropathy, was reviewed for sciatic nerve signal intensity, size, architectural distortion, bulbous enlargement, perineural fibrosis, discontinuity, and muscle denervation changes. Clinical data, electrodiagnostic testing, and surgical history were used to determine PNI grade (high, low). Descriptive and diagnostic performance statistics were applied. RESULTS Of 24 patients, there were 12 high-grade and 12 low-grade PNI. There was no significant difference in signal intensity or size between high-grade and low-grade PNI (1.3 ± 0.5 cm vs 0.9 ± 0.3 cm, P = 0.09). The sensitivity and specificity for the presence of individual features in predicting high-grade injury were 83% and 67% for architectural distortion, 58% and 75% for bulbous enlargement, 50% and 83% for perineural fibrosis, 25% and 100% for discontinuity, and 67% and 75% for skeletal muscle denervation changes, respectively. Overall, the sensitivity and specificity of MR imaging for categorizing sciatic PNI as high grade was 75% and 83%, respectively. CONCLUSIONS The MR characterization of PNI severity remains challenging. Useful features indicative of high-grade PNI include bulbous enlargement, perineural fibrosis, muscle denervation changes, and nerve discontinuity.

Although postcontrast imaging has been used for many years in musculoskeletal imaging, dynamic contrast enhanced (DCE) MRI is not routinely used in many centers around the world. Unlike conventional contrast-enhanced sequences, DCE-MRI allows the evaluation of the temporal pattern of enhancement in the musculoskeletal system, perhaps best known for its use in oncologic applications (such as differentiating benign from malignant tumors, evaluating for treatment response after neoadjuvant chemotherapy, and differentiating postsurgical changes from residual tumor). However, DCE-MRI can also be used to evaluate inflammatory processes such as Charcot foot and synovitis, and evaluate bone perfusion in entities like Legg Calve Perthes disease and arthritis. Finally, vascular abnormalities and associated complications may be better characterized with DCE-MRI than conventional imaging. The goal of this article is to review the applications and technical aspects of DCE-MRI in the musculoskeletal system. Level of Evidence: 5 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017.

Background Stratification of the fracture risk is an important treatment component for patients with multiple myeloma, which is associated with up to an 80% risk of pathologic fracture. The Mirels score, which is commonly used to estimate the fracture risk for patients with osseous lesions, was evaluated in a cohort in which fewer than 15% of lesions were caused by multiple myeloma. The behavior of multiple myeloma lesions often differs from that of lesions caused by metastatic disease, and accurate risk stratification is critical for effective care. To our knowledge, the Mirels score has not been validated specifically for multiple myeloma. Questions/purposes Our purpose was: (1) To develop a novel scoring system for the prediction of pathologic fracture in patients with long-bone lesions from multiple myeloma; and (2) to compare the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and receiver operating characteristic (ROC) area under curve (AUC) between the novel scoring system and the Mirels system. Methods Between 2003 and 2017, 763 patients at one center with the diagnosis of multiple myeloma were reviewed, of whom 174 presented with long-bone disease involvement. Of those, 5% (nine of 174) were missing data or radiographs at a minimum of 1 year and had not reached an endpoint (fracture or surgery) before that time and were therefore excluded. Many patients have more than one lesion; consequently, we used the largest lesion in each patient, resulting in 163 lesions in as many patients. Ten percent (16 of 163) of these patients eventually developed a fracture and 4% (six of 163) underwent prophylactic stabilization (excluded from analysis because of outcome uncertainty). During the study period, prophylactic stabilization was performed at the discretion of the orthopaedic oncologist. Fifty-one percent (83 of 163) of patients were female, and the mean (± SD) age was 60 ± 10 years at radiographic lesion identification. All lesions were characterized before determining whether the patient underwent pathologic fracture. We identified variables associated with pathologic fracture on univariate analysis. Variables independently significant on logistic regression analysis were used to generate scoring algorithms at varying weights and scoring cutoffs for comparison via ROC curves. We then selected a novel score based on ROC performance, and compared the sensitivity, specificity, PPV, and NPV of that scoring system to that of Mirels score. ROC AUCs were compared after bootstrapping 100,000 iterations. Alpha was set at 0.05. Results After controlling for potential confounders, such as age, sex, and duration of myeloma diagnosis, we found the following factors were independently associated with the occurrence of pathologic fracture: larger lesion size (area, cm2) (log odds 0.17; p = 0.03), longer lesion latency (years from diagnosis to lesion identification) (log odds 0.25; p = 0.03), presence of pain (relative risk [RR] 2.9; p = 0.04), and metaphyseal location (RR 3.2, compared with epiphyseal or diaphyseal; p = 0.003). These variables were used to formulate a novel scoring system. Compared with the Mirels system, the novel system was more sensitive (69% [95% CI 61 to 76] versus 38% [95% CI 30 to 46]; p 0.05), PPV (37% [95% CI 29 to 45] versus 25% [95% CI 19 to 33]; p > 0.05), NPV (96% [95% CI 91 to 99] versus 92% [95% CI 87 to 96]; p > 0.05), or AUC (0.85 [95% CI 0.74 to 0.92] versus 0.67 [95% CI 0.51 to 0.81]; p > 0.05). Conclusion The novel scoring system was found to be more sensitive than the Mirels system for predicting pathologic fracture in our retrospective cohort of patients with multiple myeloma-related bone disease. Specificity, PPV, NPV, and ROC AUC were not different with the numbers available. Thus, the novel scoring system may serve as a more effective screening tool to determine which patients with multiple myeloma would benefit from further radiologic or orthopaedic evaluation based on a skeletal survey. Level of evidence Level III, diagnostic study.

Neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2), and schwannomatosis (SWN) are three clinically distinct tumor predisposition syndromes with a shared tendency to develop peripheral and central nervous system neoplasms. Disease expression and complications of NF1, NF2, and SWN are highly variable, necessitating a multidisciplinary approach to care in order to optimize outcomes. This review will discuss the imaging appearance of NF1, NF2, and SWN and highlight the important role that imaging plays in informing management decisions in people with tumors associated with these syndromes. Recent technological advances, including the role of both whole-body and localized imaging strategies, routine anatomic and advanced magnetic resonance (MR) imaging sequences such as diffusion-weighted imaging (DWI) with quantitative apparent diffusion coefficient (ADC) mapping, and metabolic imaging techniques (MR spectroscopy and positron emission testing) are discussed in the context of the diagnosis and management of people with NF1, NF2, and SWN based on the most up-to-date clinical imaging studies.

Background: The standard of care for treatment of low-flow venous malformations (VMs) is percutaneous sclerotherapy. These lesions are seldom surgically resected, especially if the malformation is in an anatomically difficult location. Percutaneous sclerotherapy is safe and effective. However, the drawbacks to sclerotherapy are the need for repeated treatments and risks of skin ulceration, deep venous thrombosis, scarring/contractures, and nerve damage. Surgical resection can be difficult because of intraoperative bleeding, intraoperative lesional decompression, and difficulty in localization. Methods: We describe our initial experience with 11 patients who underwent surgical resection of VMs located in the hand and forearm after preembolization of 27 total sites using n-butyl-cyanoacrylate or ethylene vinyl alcohol copolymer. Results: Of the 11 patients treated, 5 had focal VMs, 3 had multifocal VMs, and 3 had diffuse VMs throughout the affected extremity. Four of the 5 patients with focal VMs were followed for at least 1 year, and no further treatment was required. All 3 of the patients with diffuse VMs have required ongoing treatment. No major functional impairments were reported, and there were no major procedure-related complications. Conclusions: Overall, embolization of the malformation before surgical resection facilitated localization, demarcation, and removal of the lesion.

PURPOSE To assess the added value of contrast-enhanced (CE) MR sequences (static CE-MR sequences, dynamic CE-MR sequences) to noncontrast enhanced MR sequences (non-CE-MR sequences) including T1, fluid-sensitive, and diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) mapping for characterizing "indeterminate" soft tissue masses (STMs) as benign or malignant. MATERIALS AND METHODS Thirty-nine patients with indeterminate STMs (27 benign, 12 malignant) underwent 3 Tesla MRI with conventional non-CE-MR sequences (T1-weighted, fluid-sensitive), DWI (b-values 50, 400, 800, ADC mapping), dynamic CE-MR sequences (7-s time resolution), and static CE-MR sequences. Two readers independently reviewed imaging in four sessions (conventional non-CE-MR sequences alone, conventional+DWI/ADC, conventional+DWI/ADC+static CE-MR sequences, conventional+DWI/ADC+static CE-MR sequences dynamic CE-MR sequences). Readers recorded the potential of malignancy at each session; reader diagnostic performance (receiver operating characteristics analysis) and inter-observer variability (weighted kappa [k]) were determined. RESULTS Diagnostic performance for distinguishing benign and malignant STMs was highest with the addition of dynamic CE-MR sequences (reader 1, area under the curve [AUC] 0.91; reader 2, AUC 0.88). The diagnostic performance of static CE-MR sequences (reader 1, AUC 0.86; reader 2, AUC 0.84) was not superior to non-CE-MR sequences with DWI (reader 1, AUC 0.88; reader 2, AUC 0.8). Interobserver agreement was: k = 0.82 (static CE-MRI), k = 0.79 (dynamic CE-MRI), k = 0.53 (non-CE-MR sequences without DWI), and k = 0.63 (with DWI). CONCLUSION Non-CE-MR sequences offer similar diagnostic performance to imaging with the addition of static CE-MR sequences, but their interobserver reliability is lower. The addition of dynamic CE-MR sequences offers the higher diagnostic performance for distinguishing benign and malignant indeterminate STMs. LEVEL OF EVIDENCE 3 J. Magn. Reson. Imaging 2017;45:390-400.

Purpose Neurofibromatosis type 2 (NF2) is a tumor predisposition syndrome characterized by bilateral vestibular schwannomas (VSs) resulting in deafness and brainstem compression. This study evaluated efficacy and biomarkers of bevacizumab activity for NF2-associated progressive and symptomatic VSs. Patients and Methods Bevacizumab 7.5 mg/kg was administered every 3 weeks for 46 weeks, followed by 24 weeks of surveillance after treatment with the drug. The primary end point was hearing response defined by word recognition score (WRS). Secondary end points included toxicity, tolerability, imaging response using volumetric magnetic resonance imaging analysis, durability of response, and imaging and blood biomarkers. Results Fourteen patients (estimated to yield > 90% power to detect an alternative response rate of 50% at alpha level of 0.05) with NF2, with a median age of 30 years (range, 14 to 79 years) and progressive hearing loss in the target ear (median baseline WRS, 60%; range 13% to 82%), were enrolled. The primary end point, confirmed hearing response (improvement maintained ≥ 3 months), occurred in five (36%) of 14 patients (95% CI, 13% to 65%; P < .001). Eight (57%) of 14 patients had transient hearing improvement above the 95% CI for WRS. No patients experienced hearing decline. Radiographic response was seen in six (43%) of 14 target VSs. Three grade 3 adverse events, hypertension (n = 2) and immune-mediated thrombocytopenic purpura (n = 1), were possibly related to bevacizumab. Bevacizumab treatment was associated with decreased free vascular endothelial growth factor (not bound to bevacizumab) and increased placental growth factor in plasma. Hearing responses were inversely associated with baseline plasma hepatocyte growth factor (P = .019). Imaging responses were associated with high baseline tumor vessel permeability and elevated blood levels of vascular endothelial growth factor D and stromal cell–derived factor 1α (P = .037 and .025, respectively). Conclusion Bevacizumab treatment resulted in durable hearing response in 36% of patients with NF2 and confirmed progressive VS-associated hearing loss. Imaging and plasma biomarkers showed promising associations with response that should be validated in larger studies.

Hereditary multiple exostoses (HME) is an autosomal dominant disorder characterized by the formation of multiple osteochondromas. Because of its superior soft tissue contrast and absence of ionizing radiation, magnetic resonance imaging is the first choice imaging technique for the evaluation of complex lesions and complications related to HME. However, multidetector computed tomography (MDCT) also can be of value in the evaluation of patients with HME, which is reviewed in this article. Topics outlined are low-dose MDCT technique, 3-dimensional visualization techniques, typical MDCT appearances, differential diagnostic considerations, and the usefulness of MDCT in the assessment of emergent and non-emergent complications related to HME, among which spinal cord compression, pneumothorax and hematothorax, pseudoaneurysms, fractures, growth disturbances, chondrosarcoma transformation, and muscular and peripheral nerve involvement.

Background: The cause of mucoid degeneration (MD) of the anterior cruciate ligament (ACL), which is commonly observed on magnetic resonance imaging (MRI) of patients with knee pain, has yet to be elucidated. Despite the limited evidence on the relationship between ACL lesions (injury and MD) and tibial morphologic features (ie, posterior tibial slope), the potential association between the presence of ACL MD and medial and lateral tibial slope (MTS and LTS) has not been well-established. Purpose: To investigate whether MTS and LTS measurements are associated with the presence of ACL MD. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Consecutive knee MRI examinations of patients referred by an orthopaedic surgeon for potential internal joint derangements were identified within a 4-year period. The presence of ACL MD and the MTS/LTS values were assessed by independent expert observers in consensus in a blinded fashion. From 413 consecutive knee MRI scans, a sample of 80 knees, including 32 knees with ACL MD (cases) and 48 knees with normal ACL (controls), were selected using propensity score matching method for age, sex, body mass index, and presence of severe medial tibiofemoral compartment cartilage damage. The association between ACL MD and MTS/LTS was evaluated using conditional regression models. Results: Knees with ACL MD had higher values of LTS (mean ± SD, 7.18° ± 3.58°) in comparison with control knees (5.32° ± 3.35°). Conditional regression analysis revealed a significant association between LTS measurements (not MTS) and ACL MD; every 1° increase in LTS was associated with a 17% (95% CI, 1%-35%) higher probability of having ACL MD. Conclusion: Excessive LTS was associated with the presence of ACL MD, independent of participants’ age, sex, BMI, and cartilage damage severity.

It has been brought to our attention that theXML file for Teodor Martin Noguerolwas incorrect in the above article in Seminars in Musculoskeletal Radiology, Volume 24, Number 4, 2020 (DOI: https://doi.org/10.1055/s-0040-1710356). The author name has been corrected in the XML file as follows: Martin Noguerol Teodoro.

The majority of peripheral musculoskeletal soft tissue masses encountered in routine clinical practice are benign and associated with an excellent prognosis, whereas a small proportion of soft tissue masses are malignant and are associated with higher morbidity and mortality. Owing to the excellent tissue contrast resolution provided, magnetic resonance imaging (MRI) is a primary modality for the diagnostic evaluation of soft tissue masses, particularly for defining the anatomic extent. MRI is also useful for the characterization of soft tissue masses; however, after the exclusion of cysts and lipomas, it is challenging to accurately categorize neoplastic lesions as benign or malignant with conventional anatomic MRI. Quantitative MRI biomarkers obtained with nonconventional pulse sequences are becoming increasingly available, and can improve the accuracy of determining the character of soft tissue masses. In this article we discuss established qualitative and emerging quantitative MRI-based biomarkers available with dynamic contrast-enhanced MRI, diffusion-weighted imaging, and MR spectroscopy and their utility for the characterization of untreated soft tissue masses. Level of Evidence: 5 Technical Efficacy Stage: 5 J. Magn. Reson. Imaging 2019;50:11-27.

Background Limited data have been published regarding the typical coronal dimensions of the femur and tibia and how they relate to each other. This can be used to aid in judging optimal operative reduction of tibial plateau fractures. The purpose of the present study was to quantify the width of tibial plateau in relation to the distal femur. Methods We reviewed 3D computed tomography (CT) scans taken between 2013 and 2016 of 42 patients (84 knees). We measured positions of the lateral tibial condyle with respect to the lateral femoral condyle (dLC) and the medial tibial condyle with respect to the medial femoral condyle (dMC) in the coronal plane. Positions of the articular edges of the lateral and medial tibia were also measured with respect to the femur (dLA and dMA). Results The mean (± standard deviation) measurements were as follows: dLC, − 0.1 ± 1.9 mm; dMC, − 4.7 ± 4.1 mm; dLA, 0.9 ± 1.0 mm; and dMA, 0.1 ± 1.5 mm. The mean (± standard deviation) ratio of tibial to femoral condylar width was 0.91 ± 0.03, and the ratio of tibial to femoral articular width was 1.01 ± 0.04. Conclusions The articular width of the tibia laterally and medially was slightly wider than the femoral articular width. These small differences and deviations indicate that the femur might be used as a reference to judge tibial plateau width reduction.

This review article discusses the updated World Health Classification of chondrogenic skeletal tumors and the role of conventional and advanced magnetic resonance (MR) imaging in the evaluation of chondrogenic skeletal lesions with emphasis on select diagnostic dilemmas. The majority of benign chondrogenic skeletal lesions have typical radiographic and MR features. Conventional MR imaging sequences can be helpful in the distinction of tumor-like lesions from chondrogenic tumors, and the evaluation of anatomic extent, particularly with regard to the detection of soft tissue masses associated with a chondrosarcoma (CS). Benign, atypical, and malignant chondrogenic lesions can have overlapping features on diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) mapping although dynamic contrast-enhanced (DCE) sequences can be helpful in the characterization of chondrogenic tumors as benign or malignant. Patients with multiple chondrogenic tumor conditions or syndromes are predisposed to developing CS and extra-skeletal malignancies, and as such, a small subset may benefit from imaging surveillance. The majority of chondrogenic skeletal lesions can be characterized confidently on imaging. In the small subset of intermediate and malignant chondrogenic lesions with overlapping imaging and pathological features, a multidisciplinary approach should be used.

Objective To describe MR imaging features of presumed vascular plexi in the periscapular (PSC) and retroclavicular (RC) locations. Materials/methods 443 consecutive MR studies performed as “brachial plexus” protocol (axialT1-W and sagittal STIR) were reviewed for presence, size and characteristics of PSC and RC plexi. Results Presumed PSC and RC vascular plexi were present in 10%. Both plexi more commonly occurred on the left side. Percutaneous biopsy (n = 1) yielded no vascular neoplasm. Conclusion RC and PSC vascular plexi are commonly encountered on routine brachial plexus MR imaging and may represent variant vascular networks, as they are frequently found on the contralateral asymptomatic side.

MRI plays a central role in the assessment of pediatric musculoskeletal soft tissue tumors. Although these neoplasms may initially be evaluated on other modalities, such as sonography, MRI is essential for accurately determining the extent of disease. Traditionally, MRI has been performed with sequences that provide excellent anatomic detail, with T1-weighted, fluid-sensitive, and static postcontrast T1-weighted sequences. However, with the introduction of noncontrast sequences such as diffusion-weighted imaging and magnetic resonance spectroscopy to the arsenal of available MRI techniques, functional and metabolic features of a neoplasm can now be examined noninvasively. These more recent MRI methods offer information for lesion characterization, the assessment of treatment response, and the distinction of postoperative scar from recurrence. Dynamic contrast-enhanced perfusion imaging is another useful functional technique that can be acquired before conventional static postcontrast imaging, without requiring additional contrast material. This review presents recent advances in MRI methodology that enable a comprehensive clinical assessment of musculoskeletal tumors in the pediatric population. The roles and challenges of combining anatomic, functional, and metabolic MRI sequences will be discussed as they relate to newly discovered soft tissue tumors in children.

Diffusion-weighted imaging (DWI) is a fast, non-contrast technique that is readily available and easy to integrate into an existing imaging protocol. DWI with apparent diffusion coefficient (ADC) mapping offers a quantitative metric for soft tissue evaluation and provides information regarding the cellularity of a region of interest. There are several available methods of performing DWI, and artifacts and pitfalls must be considered when interpreting DWI studies. This review article will review the various techniques of DWI acquisition and utility of qualitative as well as quantitative methods of image interpretation, with emphasis on optimal methods for ADC measurement. The current clinical applications for DWI are primarily related to oncologic evaluation: For the assessment of de novo soft tissue masses, ADC mapping can serve as a useful adjunct technique to routine anatomic sequences for lesion characterization as cyst or solid and, if solid, benign or malignant. For treated soft tissue masses, the role of DWI/ADC mapping in the assessment of treatment response as well as recurrent or residual neoplasm in the setting of operative management is discussed, especially when intravenous contrast medium cannot be given. Emerging DWI applications for non-neoplastic clinical indications are also reviewed.

Long thoracic nerve (LTN) injury can result in ipsilateral serratus anterior palsy and scapular winging. Traditional means of evaluating patients with suspected LTN injury include physical examination and electrodiagnostic studies. The purpose of our study is to describe high-resolution magnetic resonance (MR) findings in patients with clinical suspicion of LTN neuropathy. In this HIPAA-compliant, IRB-approved, retrospective study, two radiologists reviewed MR imaging performed for long thoracic neuropathy. Clinical presentation, electrodiagnostic studies and MR imaging of 20 subjects [mean age 37 ± 13 years; 25% (5/20) female] were reviewed. Observers reviewed MR imaging for LTN signal intensity, size, course, presence or absence of mass and secondary findings [skeletal muscle denervation (serratus anterior, trapezius, rhomboid) and scapular winging]. Descriptive statistics were reported. Clinical indications included trauma (n = 5), hereditary neuropathy (n = 1), pain (n = 8), winged scapula (n = 6), brachial plexitis (n = 4) and mass (n = 1). Electrodiagnostic testing (n = 7) was positive for serratus anterior denervation in three subjects. Abnormal LTN signal intensity, size, course or mass was present in 0/20. Secondary findings included skeletal muscle denervation in the serratus anterior in 40% (8/20), trapezius in 20% (4/20) and rhomboid in 20% (4/20). In 5% (1/20), an osteochondroma simulated a winged scapula, and in 2/20 (10%) MR showed scapular winging. High-resolution MR imaging is limited in its ability to visualize the long thoracic nerve directly, but does reveal secondary signs that can confirm a clinical suspicion of LTN injury.

OBJECTIVE. Sports-related peripheral nerve injuries are common among athletes and are often underrecognized because of symptom overlap with more usual sports-related bone, soft-tissue, and joint injuries. CONCLUSION. MRI plays an increasingly important role in the workup of peripheral nerve injuries and may reveal severe nerve abnormalities before they are diagnosed by electrodiagnostic testing or a clinical examination. Sport-specific peripheral nerve injuries and their MRI appearance will be discussed in this article.

OBJECTIVE. The purposes of this article are to discuss the technical considerations for performing quantitative diffusion-weighted MRI (DWI) with apparent diffusion coefficient (ADC) mapping, examine the role of DWI in whole-body MRI, and review how DWI with ADC mapping can serve as an adjunct to information gleaned from conventional MRI in the radiologic evaluation of musculoskeletal lesions. CONCLUSION. The primary role of whole-body DWI is in tumor detection; localized DWI is helpful in differentiating malignant bone and soft-tissue lesions. After treatment, an increase in tumor ADC values correlates with response to cytotoxic therapy. The use of DWI in the evaluation of musculoskeletal lesions requires knowledge of potential diagnostic pitfalls that stem from technical challenges and confounding biochemical factors that influence ADC maps but are unrelated to lesion cellularity.

Our purpose is to test the effect of varied in-phase (IP) and opposed-phase (OP) sequence order on characterizing marrow signal changes at 3T.The study was HIPAA compliant and IRB approved. Informed consent was waived. At 3T, IP and OP sequences were acquired in three patients with biopsy-proven osteosarcomas, using two methods: approach 1 (OP acquisition before IP acquisition) and approach 2 (OP after IP). Signal intensity (SI) measurements in 12 locations of biopsy-proven osteosarcoma and in six locations with normal bone marrow were performed independently by two experienced musculoskeletal radiologists. The signal intensity ratio (SIR) was measured within the marrow where there was T1 signal lower than skeletal muscle. A SIR 20 % on the OP compared with IP imaging was considered positive for marrow replacement, while SIR = 20 % was considered negative. Interobserver agreement was measured by the Lin concordance correlation coefficient (CCC).In 75 % (18/24) of locations within the biopsy-proven tumors, the SIR was20 % (SI drop more than 20 % in OP compared to IP) using approach 2 and in 100 % (24/24) of the locations the SIR was20 % (SI drop less than 20 % in OP compared to IP) using approach 1, indicating a high percentage of false-negative results by approach 2, and no false-negative results with approach 1. There was good agreement between observer measurement (CCC = 0.96).At 3T, the OP sequence should be acquired prior to the IP sequence, because susceptibility artifacts on a later-acquired OP sequence may lead to an erroneous interpretation of marrow signal abnormalities.

Although conventional MR imaging with contrast-enhanced T1-weighted sequences is of paramount importance for evaluating soft tissue masses, noncontrast MR sequences have emerged that facilitate their characterization. In this article, the utility and pitfalls of conventional MR imaging with T1-weighted, fluid-sensitive, and contrast-enhanced sequences will be discussed, along with that of functional (diffusion weighted imaging) and metabolic (proton MR spectroscopy) non–contrast-enhanced techniques for the purpose of soft tissue mass characterization. In particular, we discuss the application of these techniques to differentiating neoplastic or inflammatory masses that have high fluid content from benign cysts, as this distinction is a common pitfall of conventional sequences. J. Magn. Reson. Imaging 2014;39:504–511. © 2013 Wiley Periodicals, Inc.

Neurofibromatosis type 1 (NF1) is a neurocutaneous syndrome characterized by the development of multiple peripheral nerve sheath tumors, the majority of which are benign neurofibromas. However, malignant peripheral nerve sheath tumors (MPNSTs) occur with a 10 % lifetime risk in patients with NF1, often developing within a neurofibroma. When clinical suspicion for an MPNST arises, imaging with FDG PET and MRI is performed to characterize a peripheral tumor for potential malignancy. In this report, we describe a patient with NF-1 who had two peripheral tumors with similar features by PET, both suspicious for MPNST, but differing features by MRI, one of which was subsequently determined to be an MPNST and the second to be a schwannoma.

Magnetic resonance imaging (MRI) is the modality of choice for determining the extent of a primary bone tumor. This article will discuss the MRI techniques needed to accurately define the intramedullary extent of a bone sarcoma, emphasizing the need for non-contrast T1-weighted sequences and highlighting the role of chemical shift imaging.

To describe pre-treatment imaging features of pathologic fractures caused by primary bone tumors (PBTs) and metastatic bone tumors (MBTs) and determine if radiographic or cross-sectional features can differentiate the underlying pathologies associated with the fractures.Sixty-nine patients with a diagnosis of a pathologic fracture were enrolled. Biopsy established PBT as the cause of the pathologic fracture in 16 (23%) cases and MBT in 53 (77%) cases. The radiographs, computed tomography (CT) scans, and magnetic resonance imaging (MRI) scans of the subjects were retrospectively reviewed for the presence of multiple imaging features.Compared to pathologic fractures caused by MBTs, the fractures caused by PBTs demonstrated a higher incidence of lytic bone cortex, mineralization and a soft-tissue mass on radiographs, mineralization and a soft-tissue mass on CT scans, and periosteal abnormality on MRI scans (P0.01). These features also exhibited a high negative predictive value in supporting the diagnosis of an underlying PBT over MBT.Pathologic fractures caused by PBT and MBT may be differentiated by a few specific radiographic and CT imaging features, though MRI was poor for characterization of the underlying lesion. Such knowledge may assist radiologists in raising the possibility of a PBT as the cause of a pathologic fracture.

OBJECTIVES: The Response Evaluation in Neurofibromatosis and Schwannomatosis (REiNS) International Collaboration Whole-Body MRI (WB-MRI) Working Group reviewed the existing literature on WB-MRI, an emerging technology for assessing disease in patients with neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2), and schwannomatosis (SWN), to recommend optimal image acquisition and analysis methods to enable WB-MRI as an endpoint in NF clinical trials.METHODS: A systematic process was used to review all published data about WB-MRI in NF syndromes to assess diagnostic accuracy, feasibility and reproducibility, and data about specific techniques for assessment of tumor burden, characterization of neoplasms, and response to therapy.RESULTS: WB-MRI at 1.5T or 3.0T is feasible for image acquisition. Short tau inversion recovery (STIR) sequence is used in all investigations to date, suggesting consensus about the utility of this sequence for detection of WB tumor burden in people with NF. There are insufficient data to support a consensus statement about the optimal imaging planes (axial vs coronal) or 2D vs 3D approaches. Functional imaging, although used in some NF studies, has not been systematically applied or evaluated. There are no comparative studies between regional vs WB-MRI or evaluations of WB-MRI reproducibility.CONCLUSIONS: WB-MRI is feasible for identifying tumors using both 1.5T and 3.0T systems. The STIR sequence is a core sequence. Additional investigation is needed to define the optimal approach for volumetric analysis, the reproducibility of WB-MRI in NF, and the diagnostic performance of WB-MRI vs regional MRI.

Primary rhabdomyosarcoma of the bone is an extremely rare condition with few examples reported in the literature. We present the case of a 34-year-old male who presented with a lesion in the distal femur with initial imaging features consistent with Ewing sarcoma. Histologically, the lesion consisted of atypical pleomorphic polygonal rhabdomyoblasts demonstrating focal desmin and myogenin expression. A diagnosis of pleomorphic rhabdomyosarcoma was rendered. Despite systemic treatment and surgery, this patient experienced a rapidly progressive disease course. We believe this is only the second report in the orthopedic literature of a case of primary pleomorphic rhabdomyosarcoma of the bone. The key imaging, pathologic, and clinical findings are discussed.

The scapula plays a central role in shoulder motion and stability. A wide variety of anatomic variants as well as traumatic, neoplastic, and infectious pathologies can involve the scapula. Detection of scapular lesions using radiography can be challenging because of the obscuration by the overlying structures or incomplete imaging during shoulder magnetic resonance imaging or computed tomography examinations. Familiarity with imaging characteristics of these abnormalities will allow radiologists to better diagnose and characterize scapular disorders.

Purpose: To determine the minimal image quality needed to preserve diagnostic performance relative to arthroscopy in the knee. Materials and Methods: Synthetic noise was added to images from clinical MRI scans (three-dimensional SPACE pulse sequence; Siemens) from five patients who had undergone knee MRI with arthroscopic follow-up, resulting in 25 simulated sets of images with standardized signal-to-noise ratios (SNRs) of 1, 2, 5, 10, or 20. All cases were scored by four musculoskeletal radiologists progressing from low to high SNR and grading all cartilage surfaces, major ligaments and menisci on a 5-point scale. Receiver operator characteristic (ROC) curves were constructed for the detection of meniscal tears and cartilage abnormalities. The area under the ROC curve (AUC) was determined for each structure at each SNR level. In addition, reader confidence was measured and pairwise comparisons across SNR levels were performed. Results were compared with arthroscopy as the reference standard. Results: ROC AUC was maximized for meniscal tears at SNR = 5 (structure specific CNR = 3.2) and for cartilage abnormalities at SNR = 10 (CNR = 4.2). Observer confidence was maximized for menisci at SNR = 5 (CNR = 8.0), for ligaments at SNR = 10 (CNR = 13.6) and cartilage at SNR = 10 (CNR = 8.2). Conclusion: For 3D isotropic imaging in the knee, images with SNR < 10 or CNR < 10 should be rejected as nondiagnostic. J. Magn. Reson. Imaging 2013;37:1402–1408. © 2012 Wiley Periodicals, Inc.