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Purpose Determine interobserver concordance of semiautomated three-dimensional volumetric and two-dimensional manual measurements of apparent diffusion coefficient (ADC) values in soft tissue masses (STMs) and explore standard deviation (SD) as a measure of tumor ADC heterogeneity. Results Concordance correlation coefficients for mean ADC increased with more extensive sampling. Agreement on the SD of tumor ADC values was better for large regions of interest and multislice methods. Correlation between mean and SD ADC was low, suggesting that these parameters are relatively independent. Conclusion Mean ADC of STMs can be determined by volumetric quantification with high interobserver agreement. STM heterogeneity merits further investigation as a potential imaging biomarker that complements other functional magnetic resonance imaging parameters.

Image-guided percutaneous needle biopsy has become the preferred diagnostic modality for bone and soft tissue tumors. However, to the authors' knowledge, the levels of patient anxiety, pain, and satisfaction before and after the procedure have not been studied. Sixty-five patients undergoing image-guided needle biopsy of a possible bone or soft tissue tumor were prospectively surveyed to quantify preprocedure and postprocedure levels of anxiety and pain and to determine demographic and clinical correlates of anxiety, pain, and satisfaction. Anxiety was measured with the Spielberger State-Trait Anxiety Inventory, pain was measured with a visual analog scale, and satisfaction was measured by patient willingness to repeat the procedure if necessary. Statistical analysis was performed with Student's t test, Fisher's exact test, and linear regression analysis. Compared with preprocedure values, trait anxiety (defined as the underlying level of anxiety, P P P r =0.31, P =.014), whereas no relationship was seen between changes in pain and trait anxiety ( r =0.13, P =.28). Patients who were somewhat satisfied with the procedure reported higher levels of postprocedure pain than those who were completely satisfied (5.24±2.19 cm vs 1.70±2.08 cm, respectively; P r =0.41, P =.001), and there was a trend toward increasing dissatisfaction among younger patients. [ Orthopedics. 2016; 39(2):e219–e224.]

Diffusion-weighted imaging is a nonenhanced technique that can provide quantitative information about the cellularity of a musculoskeletal lesion, potentially serving as an important adjunct in initial characterization and posttreatment assessment of both osseous and soft-tissue tumors.

This article discusses the evolving role of 16-slice multidetector computed tomography, isotropic data, and 3D volume visualization.

Magnetic resonance imaging is an excellent modality for imaging pathological processes of the shoulder joint. It allows high-resolution imaging of all anatomic structures, including the glenoid, the humeral head, the articular cartilage, the acromion, the muscles and tendons of the rotator cuff, the labrum, the biceps tendon, and the glenohumeral ligaments, in multiple orthogonal planes. Numerous technical options and several pulse sequences can be utilized for the performance of magnetic resonance imaging of the shoulder. The aim of this review is to update orthopaedic surgeons on the technical aspects of performing magnetic resonance imaging of the shoulder. In addition, this report will define the normal anatomy of the shoulder as demonstrated by magnetic resonance imaging and review the spectrum of disease detectable with this technique. After reviewing this article, the reader should (1) have a basic understanding of the physics, pulse sequences, and terminology of magnetic resonance imaging; (2) be able to systematically evaluate the findings of a complete magnetic resonance imaging examination of the shoulder and know the features of normal shoulder anatomy; (3) be able to identify various tissue types on T1-weighted, fat-suppressed T2-weighted, and proton-density images; and (4) be able to diagnose certain pathological processes of the shoulder on the basis of magnetic resonance imaging findings. ### Process of Image Production First, the subject is positioned in the scanner. For magnetic resonance imaging of the shoulder, the patient is supine and the arm is held at the side, as opposed to across the chest, in order to minimize transmission of respiratory motion to the shoulder. The arm is placed in slight external rotation to optimally orient the supraspinatus tendon in order to prevent confusing overlap with the infraspinatus tendon on coronal oblique images1. The external rotation also allows maximum visualization of the supraspinatus insertion2. The magnetic field of …

Total shoulder arthroplasty is considered to be a safe procedure with a low complication rate. Cofield et al.1 reviewed the literature and reported that the overall complication rate for this procedure was 10.4% (123 of 1183). Associated complications that have been reported include infection, nerve damage, arterial injury, fracture, instability, and long-term loosening of the implant2-5. The rate of bleeding or hematoma formation after total shoulder arthroplasty has been reported as 0.17% (two of 1183)1, 2.78% (one of thirty-six)1,6, and 3.3% (five of 152)7. Most reviews of total shoulder arthroplasty have not listed bleeding as a complication of the procedure8-12. The rate of bleeding after total hip and knee replacement has been reported as 1.3% (eighteen of 1414 wounds)13, 2.4% (six of 248 primary total hip arthroplasties)14, and 5.8% (fourteen of 243 revision total hip arthroplasties)14. Patients in whom a hematoma develops after total hip or knee replacement can experience higher-than-normal pain levels, are at increased risk for infection, and have poorer rehabilitation progress than those without a hematoma13,15-17. Hematoma formation has been reported to be more common in patients who receive prophylactic or therapeutic anticoagulation therapy in the perioperative period7 than in those who do not. The impact of anticoagulation therapy on hematoma formation after total shoulder arthroplasty has not been addressed in the literature. We report the cases of two patients who, as a result of anticoagulation therapy, had development of a substantial chest wall hematoma after total shoulder replacement. These two cases represent 1.3% of the 158 shoulder arthroplasties that were performed by the senior author (E.G.M.) during the study period (from 1998 to 2005) and two …

We report a case of a 53 year old female with breast cancer and elevated glucose activity at the left greater trochanter on PET imaging. Further imaging with CT and MRI showed that this focus of increased FDG activity on PET was calcific tendinosis of the gluteus medius tendon, which mimicked metastatic disease in this patient.

Indications for computed tomography (CT) of the musculoskeletal system, especially with the advent of 16-slice multidetector CT (MDCT), are numerous. In addition to the evaluation of the trauma patient where CT is essential when imaging complex skeletal injuries, MDCT is particularly useful in patients who have had prior surgery. In postoperative cases, metal artifact typically prohibits magnetic resonance imaging evaluation, but volume-rendering of a MDCT axial database virtually eliminates streak artifact associated with hardware. For the evaluation of masses, CT provides the ability to detect and characterize calcification, cortical disruption, and periosteal reaction. In this article, these and other indications for performance of CT of the musculoskeletal system will be discussed.

We present an image overlay system to aid needle insertion procedures in computed tomography (CT) scanners. The device consists of a display and a semitransparent mirror that is mounted on the gantry. Looking at the patient through the mirror, the CT image appears to be floating inside the patient with correct size and position, thereby providing the physician with two-dimensional (2-D) "X-ray vision" to guide needle insertions. The physician inserts the needle following the optimal path identified in the CT image rendered on the display and, thus, reflected in the mirror. The system promises to reduce X-ray dose, patient discomfort, and procedure time by significantly reducing faulty insertion attempts. It may also increase needle placement accuracy. We report the design and implementation of the image overlay system followed by the results of phantom and cadaver experiments in several clinical applications.

OBJECTIVE. Our objective was to describe the technique and utility of functional MR cholangiography (fMRC) in the evaluation of the gallbladder and biliary tree.CONCLUSION. FMRC has the potential to provide a comprehensive examination for the anatomic and functional assessment of the gallbladder and biliary tree. Complex anatomic abnormalities and functional disorders can be shown by fMRC, including biliary obstruction and extravasation.

Computed tomography (CT) plays an important role in the evaluation of musculoskeletal disease in the pediatric patient. With the advent of high-performance 16-section multidetector CT, images can be produced with subsecond gantry rotation times and with submillimeter acquisition, which yields true isotropic high-resolution volume data sets; these features are not attainable with older spiral CT technology. Such capabilities are particularly helpful in the evaluation of pediatric patients by virtually eliminating the need for sedation and minimizing dependence on patient cooperation. The role of three-dimensional (3D) volume imaging in the evaluation of pediatric musculoskeletal disease continues to evolve, with this technique becoming increasingly important in detection and characterization of lesions as well as in decisions about patient care. Specific designs and protocols for multidetector CT studies can be selected to minimize radiation dose to the patient. Principal clinical applications of 3D CT in evaluation of the pediatric musculoskeletal system include developmental abnormalities, trauma, neoplasms, and postoperative imaging.

We present a 2D image overlay device to assist needle placement on computed tomography (CT) scanners.The system consists of a flat display and a semitransparent mirror mounted on the gantry. When the physician looks at the patient through the mirror, the CT image appears to be floating inside the body with correct size and position as if the physician had 2D 'X-ray vision'. The physician draws the optimal path on the CT image. The composite image is rendered on the display and thus reflected in the mirror. The reflected image is used to guide the physician in the procedure. In this article, we describe the design and various embodiments of the 2D image overlay system, followed by the results of phantom and cadaver experiments in multiple clinical applications.Multiple skeletal targets were successfully accessed with one insertion attempt. Generally, successful access was recorded on liver targets when a clear path opened, but the number of attempts and accuracy showed variability because of occasional lack of access. Soft tissue deformation further reduced the accuracy and consistency in comparison to skeletal targets.The system demonstrated strong potential for reducing faulty needle insertion attempts, thereby reducing X-ray dose and patient discomfort.

In the initial evaluation of common pancreatic disorders, MR cholangiopancreatography (MRCP) has replaced the use of diagnostic endoscopic retrograde cholangiopancreatography (ERCP) at many institutions. MRCP is a heavily T2-weighted MR sequence that depicts the fluid-containing pancreatic duct in a noninvasive manner, avoiding potential complications associated with ERCP. MRCP is useful in the setting of pancreatitis for the identification of aberrant ductal anatomy and complications, and is valuable for detecting and characterizing cystic pancreatic masses. Furthermore, with the addition of conventional T1-weighted, T2-weighted, and gadolinium-enhanced sequences to MRCP, pancreatic adenocarcinoma can also be detected and staged. This article reviews MRCP with regard to the evaluation of common pancreatic diseases, with emphasis on its use for guiding treatment options.

After the femoral head, the humeral head is the second most common site for osteonecrosis and its occurrence has been associated with trauma (especially three and four-part fractures), corticosteroid use, sickle-cell disease, alcoholism, dysbarism (or caisson disease), Gaucher disease, or other systemic conditions1. Osteonecrosis of the humeral head is extremely uncommon in children and generally is not associated with conditions that affect the femoral head, such as Perthes disease. To our knowledge, osteonecrosis of the humeral head in an adolescent as a surgical complication has not been reported in the literature. We report a case of humeral head osteonecrosis in a child occurring after shoulder stabilization for the treatment of recurrent shoulder dislocation. The complication was treated nonsurgically, and the osteonecrosis resolved within nine months, as documented by magnetic resonance imaging. Our patient and his family were informed that data concerning the case would be submitted for publication. Athirteen-year-old male was referred to our clinic for evaluation of recurrent dislocation of the right shoulder. The first injury occurred at the age of eleven when he sustained a hyperabduction injury to the right arm while wrestling. He had immediate pain in the right shoulder but did not seek medical attention. He sustained the first dislocation of the right shoulder while diving into a pool approximately six months after the initial injury. Three months later, he sustained a hyperabduction injury and dislocated the same shoulder while playing football. Each time, the dislocated shoulder was reduced in an emergency room and was treated with immobilization in a sling for a brief period of time. Three weeks before presentation to our clinic, he dislocated the right shoulder while throwing a Frisbee. The patient was otherwise healthy and did not have a history of steroid use, sickle-cell anemia, Ehlers-Danlos syndrome, instability of other …

Aim To identify magnetic resonance imaging (MRI) features differentiating high-grade (>5% round-cell component) from low-grade myxoid liposarcomas (LPS) (≤5% round-cell component). Materials and methods Informed consent was waived. Patients with myxoid LPS and MRI before biopsy, neoadjuvant therapy, and surgery were included retrospectively. High-grade components were recorded from histological specimens by a pathologist (24 years of experience). Images were evaluated by a senior radiologist (>12 years of experience) for tumour size, location, tissue layer, and MRI features (signal intensity, heterogeneity, margin, and perilesional characteristics). Descriptive statistics, Fisher's exact test to identify associations with a round-cell component, and multivariate logistic regression to identify independent predictors of high-grade tumours were used. Results Thirty-one patients (16 women [mean 51.1 years; range 19–79 years] and 15 men [mean 45.5 years; range 18–95 years]) with myxoid LPS (23 low-grade, eight high-grade) were included. All high-grade lesions had lipid signal, a peritumoural capsule and peritumoural contrast enhancement, and more commonly exhibited heterogeneous signal; however, the average size of ≥10 cm was the strongest independent indicator of high-grade status (odds ratio [OR], 14.6; 95% confidence interval [CI]: 1.6, 131). Conclusion Size ≥10 cm is most strongly associated with high-grade myxoid LPS (round-cell component >5%). Other features possibly differentiating high-grade from low-grade status include lesion margin, lipid signal, and perilesional characteristics.

Hand and wrist infections can present with a spectrum of manifestations ranging from cellulitis to deep-space collections. The various infectious processes can be categorised as superficial or deep infections based on their respective locations relative to the tendons. Superficial hand infections are located superficial to the tendons and are comprised of cellulitis, lymphangitis, paronychia, pulp-space infections, herpetic whitlow, and include volar as well as dorsal subcutaneous abscesses. Deep hand infections are located deep to the tendon sheaths and include synovial space infections, such as infectious tenosynovitis, deep fascial space infections, septic arthritis, necrotising fasciitis, and osteomyelitis. Knowledge of hand and wrist compartmental anatomy is essential for the accurate diagnosis and management of hand infections. Although early and superficial infections of the hand may respond to non-surgical management, most hand infections are surgical emergencies. Multidetector computed tomography (MDCT), with its muliplanar reformation (MPR) and three-dimensional (3D) capabilities, is a powerful tool in the emergency setting for the evaluation of acute hand and wrist pathology. The clinical and imaging features of hand and wrist infections as evident on MDCT will be reviewed with emphasis on contiguous and closed synovial and deep fascial spaces. Knowledge of hand compartmental anatomy enables accurate characterisation of the infectious process and localise the extent of disease in the acute setting.

To describe the MRI appearance of traumatic neuromas on non-contrast and contrast-enhanced MRI sequences. This IRB-approved, HIPAA-compliant study retrospectively reviewed 13 subjects with 20 neuromas. Two observers reviewed pre-operative MRIs for imaging features of neuroma (size, margin, capsule, signal intensity, heterogeneity, enhancement, neurogenic features and denervation) and the nerve segment distal to the traumatic neuroma. Descriptive statistics were reported. Pearson’s correlation was used to examine the relationship between size of neuroma and parent nerve. Of 20 neuromas, 13 were neuromas-in-continuity and seven were end-bulb neuromas. Neuromas had a mean size of 1.5 cm (range 0.6–4.8 cm), 100 % (20/20) had indistinct margins and 0 % (0/20) had a capsule. Eighty-eight percent (7/8) showed enhancement. All 100 % (20/20) had tail sign; 35 % (7/20) demonstrated discontinuity from the parent nerve. None showed a target sign. There was moderate positive correlation (r = 0.68, p = 0.001) with larger neuromas arising from larger parent nerves. MRI evaluation of the nerve segment distal to the neuroma showed increased size (mean size 0.5 cm ± 0.4 cm) compared to the parent nerve (mean size 0.3 cm ± 0.2 cm). Since MRI features of neuromas include enhancement, intravenous contrast medium cannot be used to distinguish neuromas from peripheral nerve sheath tumours. The clinical history of trauma with the lack of a target sign are likely the most useful clues. • MRI features of neuromas include enhancement and lack of a target sign. • Contrast material cannot be used to distinguish traumatic neuromas from PNSTs. • Traumatic neuromas can simulate peripheral nerve neoplasms on imaging.

SummaryObjectiveTo assess the prevalence of anterior cruciate ligament (ACL) mucoid degeneration in patients referred for routine knee magnetic resonance (MR) imaging, and its association with age and structural joint damage.MethodFour independent radiologists assessed 413 consecutive knee MR examinations for the presence of a normal or ruptured ACL, or ACL mucoid degeneration. Knees with ACL mucoid degeneration were frequency matched by age, sex, and MR field strength with consecutive control knees with a normal ACL (1:2 ratio). Differences in meniscal and cartilage damage of the tibiofemoral compartments, as determined by the Whole-Organ MR Imaging Score (WORMS) system, were compared by Mann–Whitney U tests. Multivariable logistic regression analysis identified the association of ACL mucoid degeneration with severe MTFC cartilage damage (WORMS≥5).ResultsPatients with ACL mucoid degeneration (n = 36; 36% males; median age 55.5 years, range: 26–81) were older than patients with a normal (P 50 years.

Diffusion-weighted (DW) imaging is a functional magnetic resonance (MR) imaging technique that can readily be incorporated into a routine non-contrast material-enhanced MR imaging protocol with little additional scanning time. DW imaging is based on changes in the Brownian motion of water molecules caused by tissue microstructure. The apparent diffusion coefficient (ADC) is a quantitative measure of Brownian movement: Low ADC values typically reflect highly cellular microenvironments in which diffusion is restricted by the presence of cell membranes, whereas acellular regions allow free diffusion and result in elevated ADC values. Thus, with ADC mapping, one may derive useful quantitative information regarding the cellularity of a musculoskeletal lesion using a nonenhanced technique. The role of localized DW imaging in differentiating malignant from benign osseous and soft-tissue lesions is still evolving; when carefully applied, however, this modality has proved helpful in a subset of tumor types, such as nonmyxoid soft-tissue tumors. Studies of the use of DW imaging in assessing the treatment response of both osseous and soft-tissue tumors have shown that higher ADC values correlate with better response to cytotoxic therapy. Successful application of DW imaging in the evaluation of musculoskeletal lesions requires familiarity with potential diagnostic pitfalls that stem from technical artifacts and confounding factors unrelated to lesion cellularity. Further investigation is needed to evaluate the impact of DW imaging-ADC mapping on management and outcome in patients with musculoskeletal lesions.

High-resolution multidetector computed tomography (MDCT) arthrography of the shoulder can diagnose internal derangement of the glenohumeral joints including abnormalities of the rotator cuff, glenoid labrum, and articular cartilage. Isotropic data sets and postprocessing techniques enable interactive three-dimensional image analysis that is capable of reducing artifacts for metal implants. In this article, we review the indications for MDCT arthrography of the shoulder, highlight techniques and important features of the MDCT acquisition, and review normal and abnormal MDCT arthrography appearances of the glenohumeral joint.

Magnetic resonance spectroscopy (MRS) is an imaging approach that allows for the noninvasive molecular characterization of a region of interest. By detecting signals of water, lipids, and other metabolites, MRS can provide metabolic information for lesion characterization and assessment of treatment response. Although MRS has been routinely used in the brain, clinical applications within the musculoskeletal system have only more recently emerged. The aim of this article is to review the technical considerations for performing MRS in the musculoskeletal system, focusing on proton MRS, and to discuss its potential roles in musculoskeletal tumor imaging and the assessment of muscle physiology and disease.

High-resolution multidetector computed tomography (MDCT) has played a pivotal role in assessing patients following trauma; however, recent advancements in technology including dual-energy CT, as well as multiplanar and three-dimensional (3D) capabilities, are expanding the potential clinical applications of CT to include nontraumatic pathologies. This article will review optimal technical parameters for the creation of MDCT and 3DCT images and illustrate the imaging capabilities of 3DCT imaging for demonstrating nontraumatic hand and wrist pathology.

To investigate the accuracy of quantitative diffusion-weighted imaging with apparent diffusion coefficient (ADC) mapping for characterizing bone lesions as benign or malignant.At 3T, 31 subjects with intramedullary lesions imaged by DWI (b-values 50, 400, 800s/mm(2)) were included. ADC values (minimum, mean, maximum) were recorded by three observers independently. Interobserver variability and differences between ADC values in benign and malignant lesions were assessed (unpaired t-test, receiver operating characteristic (ROC) analysis).Of 31 lesions, 18 were benign (osteoblastic (n=1), chondroid (n=6), cysts (n=4), hemangiomatosis (n=1), fibrous (n=3), eosinophilic granuloma (n=1), giant cell tumor (n=1), osteomyelitis (n=1)) and 13 were malignant (primary (n=5), metastases (n=8)). Overall, there were higher minimum (1.27 × 10(-3)mm(2)/s vs 0.68 × 10(-3)mm(2)/s, p0.001), mean (1.68 × 10(-3)mm(2)/s vs 1.13 × 10(-3)mm(2)/s, p0.001), and maximum (2.09 × 10(-3)mm(2)/s vs 1. 7 × 10(-3)mm(2)/s, p=0.03). ADC values in benign lesions compared with those in malignancies. ROC analysis revealed areas under the curve for minimum, mean, and maximum ADC values of 0.91, 0.85, and 0.71, respectively. ADC measurements were made with high inter-observer concordance (ρ=0.83-0.96).Quantitative ADC maps may have predictive value for the characterization of bone lesions. Benign lesions generally have higher minimum, mean, and maximum ADC values than malignancies, with the minimum value offering the highest accuracy for characterization.

Differentiating benign from malignant peripheral nerve sheath tumors can be very challenging using conventional MR imaging. Our aim was to test the hypothesis that conventional and functional MR imaging can accurately diagnose malignancy in patients with indeterminate peripheral nerve sheath tumors.This institutional review board-approved, Health Insurance Portability and Accountability Act-compliant study retrospectively reviewed 61 consecutive patients with 80 indeterminate peripheral nerve sheath tumors. Of these, 31 histologically proved peripheral nerve sheath tumors imaged with conventional (unenhanced T1, fluid-sensitive, contrast-enhanced T1-weighted sequences) and functional MR imaging (DWI/apparent diffusion coefficient mapping, dynamic contrast-enhanced MR imaging) were included. Two observers independently assessed anatomic (size, morphology, signal) and functional (ADC values, early arterial enhancement by dynamic contrast-enhanced MR) features to determine interobserver agreement. The accuracy of MR imaging for differentiating malignant from benign was also determined by receiver operating characteristic analysis.Of 31 peripheral nerve sheath tumors, there were 9 malignant (9%) and 22 benign ones (81%). With anatomic sequences, average tumor diameter (6.3 ± 1.8 versus 3.9 ± 2.3 mm, P = .009), ill-defined/infiltrative margins (77% versus 32%; P = .04), and the presence of peritumoral edema (66% versus 23%, P = .01) were different for malignant peripheral nerve sheath tumors and benign peripheral nerve sheath tumors. With functional sequences, minimum ADC (0.47 ± 0.32 × 10(-3) mm(2)/s versus 1.08 ± 0.26 × 10(-3) mm(2)/s; P.0001) and the presence of early arterial enhancement (50% versus 11%; P = .03) were different for malignant peripheral nerve sheath tumors and benign peripheral nerve sheath tumors. The minimum ADC (area under receiver operating characteristic curve was 0.89; 95% confidence interval, 0.73-0.97) and the average tumor diameter (area under the curve = 0.8; 95% CI, 0.66-0.94) were accurate in differentiating malignant peripheral nerve sheath tumors from benign peripheral nerve sheath tumors. With threshold values for minimum ADC ≤ 1.0 × 10(-3) mm(2)/s and an average diameter of ≥4.2 cm, malignancy could be diagnosed with 100% sensitivity (95% CI, 66.4%-100%).Average tumor diameter and minimum ADC values are potentially important parameters that may be used to distinguish malignant peripheral nerve sheath tumors from benign peripheral nerve sheath tumors.

To assess visualization tasks using cone-beam CT (CBCT) compared to multi-detector CT (MDCT) for musculoskeletal extremity imaging. Ten cadaveric hands and ten knees were examined using a dedicated CBCT prototype and a clinical multi-detector CT using nominal protocols (80kVp-108mAs for CBCT; 120kVp- 300mAs for MDCT). Soft tissue and bone visualization tasks were assessed by four radiologists using five-point satisfaction (for CBCT and MDCT individually) and five-point preference (side-by-side CBCT versus MDCT image quality comparison) rating tests. Ratings were analyzed using Kruskal–Wallis and Wilcoxon signed-rank tests, and observer agreement was assessed using the Kappa-statistic. Knee CBCT images were rated “excellent” or “good” (median scores 5 and 4) for “bone” and “soft tissue” visualization tasks. Hand CBCT images were rated “excellent” or “adequate” (median scores 5 and 3) for “bone” and “soft tissue” visualization tasks. Preference tests rated CBCT equivalent or superior to MDCT for bone visualization and favoured the MDCT for soft tissue visualization tasks. Intraobserver agreement for CBCT satisfaction tests was fair to almost perfect (κ ~ 0.26–0.92), and interobserver agreement was fair to moderate (κ ~ 0.27–0.54). CBCT provided excellent image quality for bone visualization and adequate image quality for soft tissue visualization tasks. • CBCT provided adequate image quality for diagnostic tasks in extremity imaging. • CBCT images were “excellent” for “bone” and “good/adequate” for “soft tissue” visualization tasks. • CBCT image quality was equivalent/superior to MDCT for bone visualization tasks.

With recent advances in multidetector computed tomography (MDCT) acquisition and reconstruction options, MDCT can now be used successfully for evaluating tendon abnormalities. In this article, MDCT protocol optimization for the imaging of tendons is underscored, and applications of MDCT for assessing tendon pathology are highlighted. Although our retrospective experience of CT imaging with 2-dimensional multiplanar reconstructions and 3-dimensional postprocessing techniques is reviewed, potential applications for newer CT technologies, including dual-energy CT and 4-dimensional CT imaging of the peripheral tendons, are also discussed.

To identify the magnetic resonance (MR) imaging features that can be used to differentiate high-grade from low-grade soft-tissue sarcoma (STS).Institutional review board approval was obtained, and informed consent was waived. Patients with STS who had undergone MR imaging with T1-weighted, T2-weighted, and contrast material-enhanced sequences prior to neoadjuvant therapy and surgery were included retrospectively. Tumor grade (grades 1-3) was recorded from the histologic specimen for each STS. Images were evaluated by two observers for tumor size and MR features (signal intensity, heterogeneity, margin, and perilesional characteristics) on images obtained with each sequence. Descriptive statistics for low-grade (grade 1) and high-grade (grades 2 and 3) STS were recorded, and the accuracy of individual features was determined. A multivariate logistic regression model was developed to identify features that were independently predictive of a high-grade tumor.Ninety-five patients (48 female [mean age, 55.8 years; age range, 7-96 years] and 47 male [mean age, 55.3 years; age range, 1-87 years]) with STS (16 patients with grade 1 STS, 34 patients with grade 2 STS, and 45 patients with grade 3 STS) were included. High-grade STS differed from low-grade STS in size (5 cm, P = .004), tumor margin (partly or poorly defined margin on T1-weighted images, P = .002; with other sequences, P.001), internal signal intensity composition (heterogeneous signal intensity on T2-weighted images, P = .009), and peritumoral characteristics (peritumoral high signal intensity on T2-weighted images, P = .025; peritumoral enhancement on contrast-enhanced T1-weighted images, P.001). The logistic regression model showed that peritumoral contrast enhancement is the strongest independent indicator of high-grade status (odds ratio, 13.6; 95% confidence interval: 2.9, 64.6).Among several MR imaging features that aid in the discrimination of high-grade from low-grade sarcomas, the presence of peritumoral contrast enhancement is a feature that may be solely used to diagnose high-grade STS.

To determine the added value of functional magnetic resonance (MR) sequences (dynamic contrast material-enhanced [DCE] and quantitative diffusion-weighted [DW] imaging with apparent diffusion coefficient [ADC] mapping) for the detection of recurrent soft-tissue sarcomas following surgical resection.This retrospective study was approved by the institutional review board. The requirement to obtain informed consent was waived. Thirty-seven patients referred for postoperative surveillance after resection of soft-tissue sarcoma (35 with high-grade sarcoma) were studied. Imaging at 3.0 T included conventional (T1-weighted, fluid-sensitive, and contrast-enhanced T1-weighted imaging) and functional (DCE MR imaging, DW imaging with ADC mapping) sequences. Recurrences were confirmed with biopsy or resection. A disease-free state was determined with at least 6 months of follow-up. Two readers independently recorded the signal and morphologic characteristics with conventional sequences, the presence or absence of arterial enhancement at DCE MR imaging, and ADCs of the surgical bed. The accuracy of conventional MR imaging in the detection of recurrence was compared with that with the addition of functional sequences. The Fisher exact and Wilcoxon rank sum tests were used to define the accuracy of imaging features, the Cohen κ and Lin interclass correlation were used to define interobserver variability, and receiver operating characteristic analysis was used to define a threshold to detect recurrence and assess reader confidence after the addition of functional imaging to conventional sequences.There were six histologically proved recurrences in 37 patients. Sensitivity and specificity of MR imaging in the detection of tumor recurrence were 100% (six of six patients) and 52% (16 of 31 patients), respectively, with conventional sequences, 100% (six of six patients) and 97% (30 of 31 patients) with the addition of DCE MR imaging, and 60% (three of five patients) and 97% (30 of 31 patients) with the addition of DW imaging and ADC mapping. The average ADC of recurrence (1.08 mm(2)/sec ± 0.19) was significantly different from those of postoperative scarring (0.9 mm(2)/sec ± 0.00) and hematomas (2.34 mm(2)/sec ± 0.72) (P = .03 for both).The addition of functional MR sequences to a routine MR protocol, in particular DCE MR imaging, offers a specificity of more than 95% for distinguishing recurrent sarcoma from postsurgical scarring.

Background. Magnetic resonance imaging (MRI) should be considered essential to the presurgical evaluation of pancreatic adenocarcinoma, to accurately detect resectable lesions and to spare patients with non-resectable tumors the morbidity, mortality, and expense of unnecessary surgery. This article is a review of the MRI characteristics of pancreatic adenocarcinoma, the features that determine its resectability, and the optimal MR sequences needed for its effective evaluation. The role of MRI imaging is contrasted with other imaging and invasive modalities for the diagnosis and staging of pancreatic adenocarcinoma.

BACKGROUND AND PURPOSE: The characterization of peripheral nerve sheath tumors is challenging. The purpose here was to investigate the diagnostic value of quantitative proton MR spectroscopy at 3T for the characterization of peripheral nerve sheath tumors as benign or malignant, compared with PET. MATERIALS AND METHODS: Twenty participants with 24 peripheral nerve sheath tumors underwent MR spectroscopy by use of a point-resolved sequence (TE, 135 ms). Six voxels were placed in 4 histologically proven malignant peripheral nerve sheath tumors and 22 voxels in 20 benign peripheral nerve sheath tumors (9 histologically proven, 11 with documented stability). The presence or absence of a trimethylamine signal was evaluated, the trimethylamine concentration estimated by use of phantom replacement methodology, and the trimethylamine fraction relative to Cr measured. MR spectroscopy results for benign and malignant peripheral nerve sheath tumors were compared by use of a Mann-Whitney test, and concordance or discordance with PET findings was recorded. RESULTS: In all malignant tumors and in 9 of 18 benign peripheral nerve sheath tumors, a trimethylamine peak was detected, offering the presence of trimethylamine as a sensitive (100%), but not specific (50%), marker of malignant disease. Trimethylamine concentrations (2.2 ± 2.8 vs 6.6 ± 5.8 institutional units; P < .049) and the trimethylamine fraction (27 ± 42 vs 88 ± 22%; P < .012) were lower in benign than malignant peripheral nerve sheath tumors. A trimethylamine fraction threshold of 50% resulted in 100% sensitivity (95% CI, 58.0%–100%) and 72.2% (95% CI, 59.5%–75%) specificity for distinguishing benign from malignant disease. MR spectroscopy and PET results were concordant in 12 of 16 cases, (2 false-positive results for MR spectroscopy and PET each). CONCLUSIONS: Quantitative measurement of trimethylamine concentration by use of MR spectroscopy is feasible in peripheral nerve sheath tumors and shows promise as a method for the differentiation of benign and malignant lesions. Trimethylamine presence within a peripheral nerve sheath tumor is a sensitive marker of malignant disease, but quantitative measurement of trimethylamine content is required to improve specificity. MPNST : malignant peripheral nerve sheath tumor NF-1 : neurofibromatosis type 1 PNST : peripheral nerve sheath tumor SUV : standard uptake values TMA : trimethylamine

OBJECTIVE: To investigate the accuracy of quantitative diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) mapping for characterizing soft tissue masses (STMs) as cysts or solid masses. MATERIALS AND METHODS: This IRB-approved retrospective study included 36 subjects with 37 STMs imaged by conventional MRI (T1-weighted, T2-weighted, contrast-enhanced T1-weighted sequences) and DWI (b-values 50, 400, 800 s/mm(2)) with ADC mapping. STMs were defined as non-solid cysts by histology or clinical follow-up, and as solid by histology. For each STM, ADC values (range, mean) were recorded by two observers. Differences between ADC values in cysts and solid STMs were compared using Wilcoxon rank-sum and receiver-operating characteristic (ROC) analysis. RESULTS: There were higher minimum (1.65 vs 0.68, p =0.003) and mean (2.31 vs 1.45, p =0.005) ADC values in cysts than solid STMs respectively. Areas under the ROC for minimum and mean ADC values were 0.82 and 0.81 respectively. Using threshold ADC values of 1.8 (minimum) or 2.5 (mean) yielded a sensitivity of 60 % and 80 % respectively, and a specificity of 100 % for classifying a STM as a cyst; for tumors with high fluid–signal intensity, the performance of these threshold values was maintained. CONCLUSION: Diffusion-weighted imaging with ADC mapping provides a non-contrast MRI alternative for the characterization of STMs as cysts or solid masses. Threshold ADC values exist that provide 100 % specificity for differentiating cysts and solid STMs, even for tumors of high fluid–signal intensity on T2-weighted images.

We demonstrate the clinical use of an MR angiography sequence performed with sparse k-space sampling (MRA), as a method for dynamic contrast-enhanced (DCE)-MRI, and apply it to the assessment of sarcomas for treatment response.Three subjects with sarcomas (2 with osteosarcoma, 1 with high-grade soft tissue sarcomas) underwent MRI after neoadjuvant therapy/prior to surgery, with conventional MRI (T1-weighted, fluid-sensitive, static post-contrast T1-weighted sequences) and DCE-MRI (MRA, time resolution = 7-10 s, TR/TE 2.4/0.9 ms, FOV 40 cm(2)). Images were reviewed by two observers in consensus who recorded image quality (1 = diagnostic, no significant artifacts, 2 = diagnostic,25 % artifacts, 3 = nondiagnostic) and contrast enhancement characteristics by static MRI (presence/absence of contrast enhancement, percentage of enhancement) and DCE-MRI (presence/absence of arterial enhancement with time-intensity curves). Results were compared with histological response (defined as5 % viable tumor [soft tissue sarcoma] or10 % [bone sarcoma] following resection).Diagnostic quality for all conventional and DCE-MRI sequences was rated as 1. In 2 of the 3 sarcomas, there was good histological response (≤5 % viable tumor); in 1 there was poor response (50 % viable tumor). By static post-contrast T1-weighted sequences, there was enhancement in all sarcomas, regardless of response (up to75 % with good response,75 % with poor response). DCE-MRI findings were concordant with histological response (arterial enhancement with poor response, no arterial enhancement with good response).Unlike conventional DCE-MRI sequences, an MRA sequence with sparse k-space sampling is easily integrated into a routine musculoskeletal tumor MRI protocol, with high diagnostic quality. In this preliminary work, tumor enhancement characteristics by DCE-MRI were used to assess treatment response.

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.

Although the function of magnetic resonance (MR) imaging in the evaluation of musculoskeletal tumors has traditionally been to help identify the extent of disease prior to treatment, its role continues to evolve as new techniques emerge. Conventional pulse sequences remain heavily used and useful, but with the advent of chemical shift imaging, diffusion-weighted imaging, perfusion imaging and MR spectroscopy, additional quantitative metrics have become available that may help expand the role of MR imaging to include detection, characterization, and reliable assessment of treatment response. This review discusses a multiparametric approach to the evaluation of musculoskeletal tumors, with a focus on the utility and potential added value of various pulse sequences in helping establish a diagnosis, assess pretreatment extent, and evaluate a tumor in the posttreatment setting for recurrence and treatment response. Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12111740/-/DC1 © RSNA, 2012

Tears of the proximal long head of the biceps tendon are among the most common tendon tears in the body. In most cases, the diagnosis is easily determined based on the history and physical examination. However, malignant soft tissue tumors can simulate proximal biceps tendon tears. Although tumors simulating tears of the distal biceps tendon at the elbow have been reported, to the authors’ knowledge, no previous cases of tumors simulating or being mistaken for proximal biceps tendon tears have been reported. This article describes 2 cases of malignant sarcomas initially mistaken for tears of the long head of the biceps tendon. In the first case, a 62-year-old woman developed swelling in her arm after feeling a twinge in her shoulder. A magnetic resonance imaging scan was misread as a biceps tendon tear and not treated by the examining physician. In the second case, a mass appeared with little trauma in the brachium of a 70-year-old man. On physical examination, the mass was hard to palpation. In each case, biopsy revealed a soft tissue sarcoma. Both patients underwent wide excision with radiation and are currently disease free. These 2 cases emphasize the importance of obtaining a good history and of performing a thorough shoulder and arm examination in patients with deformities consistent with tears of the long head of the biceps tendon.

A professional baseball player presented to the orthopaedic clinic for a preseason assessment because of continued lumbar spine and flank pain. He had a laparoscopic appendectomy for a perforated appendix 8 months before his presentation. He was able to finish the previous season with only mild limitation. He presented with back pain that limited his activity. His examination was nonlocalizing, but subsequent computed tomography revealed a hepatic abscess. The abscess was drained; he was treated with intravenous antibiotics; and his symptoms resolved.

OBJECTIVE. Limb salvage surgery comprises surgical techniques designed to resect musculoskeletal extremity tumors and subsequently reconstruct a limb with an acceptable oncologic, functional, and cosmetic result. Today, 70???90% of malignant extremity tumors are being treated with limb salvage surgery. CONCLUSION. The purpose of this article is to describe the operative techniques, review the imaging techniques, and to illustrate imaging findings related to the surgeries in complicated and uncomplicated cases.

OBJECTIVE. The purposes of this review are to summarize the indications for MDCT arthrography of the shoulder, highlight the features of MDCT acquisition, and describe the normal and abnormal MDCT arthrographic appearances of the shoulder. CONCLUSION. MDCT arthrography is a valid alternative for shoulder imaging of patients with contraindications to MRI or after failed MRI. MDCT arthrography is accurate for assessment of a variety of shoulder abnormalities and, with further validation, may become the imaging test of choice for evaluation of the postoperative shoulder.

The unfused acromial apophysis of an os acromiale typically is an undetected orthopedic anomaly with minimal symptoms. In some instances, however, pain and disability can result from motion between the unfused bone fragments. Trauma to the acromion can similarly displace the unfused os acromiale or can result in chronic symptoms of pain and swelling. In this article, we report the case of a young man who had a fractured os acromiale secondary to trauma and presented with the signs and symptoms of a septic glenohumeral joint.

Chondrosarcomas are malignant neoplasms of mesenchymal origin and represent a heterogeneous group of tumors ranging from indolent, low-grade lesions to aggressive, high-grade neoplasms. The early diagnosis and treatment of chondrosarcomas is paramount to achieving a better prognosis. Multiple imaging modalities have been used for the purpose of initial detection, characterization, and staging, as well as for the performance of image-guided biopsies. As imaging techniques continue to evolve, radiologists are assuming an increasingly important role in the management of chondrosarcomas. This review describes the imaging characteristics of chondrosarcomas on multiple modalities and emphasizes the imaging features that may assist in differentiating these tumors from their benign counterparts, enchondromas and osteochondromas, which frequently still pose challenging diagnostic dilemmas.

For the post-operative patient, conventional axial computed tomography (CT) imaging and 2D multiplanar reconstruction are of limited value because of the beam-hardening artifact. However, three-dimensional (3D) CT imaging is an effective means of detecting subtle fracture healing, or confirming non-union, and for evaluating the integrity of metal hardware. In this article we emphasize the advantages of 3D CT imaging in the assessment and preoperative planning of non-union for patients who have been surgically treated for fractures.

The posterior tibial tendon (PTT) is the most important dynamic stabilizer of the medial ankle and longitudinal arch of the foot. PTT dysfunction is a degenerative disorder of the tendon, which secondarily involves multiple ligaments, joint capsules, fascia, articulations, and bony structures of the ankle, hindfoot, midfoot, and forefoot. When the tendon progressively attenuates, the patient develops a painful, progressive collapsed flatfoot or pes planovalgus deformity. This comprehensive review illustrates the 3-Tesla magnetic resonance imaging (3T MRI) features of PTT dysfunction. In addition, the reader will gain knowledge of the expected pathologic findings on MRI, as they are related to clinical staging of PTT dysfunction.

The purpose of this study is to establish the feasibility and potential value of measuring the concentration of choline-containing compounds by proton MR spectroscopy (MRS) in musculoskeletal lesions at 3 T.Thirty-three subjects with 34 musculoskeletal lesions (four histologically proven malignant, 13 histologically proven benign or proven benign by follow-up analysis, and 17 posttreatment fibrosis with documented stability for 6-36 months) underwent single-voxel 3-T MRS studies. In each case, both water-suppressed and water-unsuppressed scans were obtained. The quality of the scans was recorded as excellent, adequate, or nondiagnostic, and the choline concentration was measured using water as the internal reference. The choline concentrations of benign and malignant lesions were compared using the Mann-Whitney test.Spectral quality was excellent in 26 cases, adequate in four cases, and nondiagnostic in four cases. For malignant lesions (three sarcomas), the choline concentrations were 1.5, 2.9, and 3.8 mmol/kg, respectively. For five benign lesions (two neurofibromas, two schwannomas, and one enchondroma), the choline concentrations were 0.11, 0.28, 0.13, 0.8, and 1.2 mmol/kg, respectively. For seven benign lesions (two hematomas, two bone cysts, one lipoma, one giant cell tumor, and one pigmented villonodular synovitis), the spectra showed negligible choline content. For three posttreatment fibrosis cases, the choline concentration range was 0.2-0.4 mmol/kg. For the remaining 12 posttreatment fibrosis cases, the spectra showed negligible choline content. Average choline concentrations were different for malignant and benign lesions (2.7 vs 0.5 mmol/kg; p = 0.01).The measurement of choline concentration within musculoskeletal lesions by MRS is feasible using an internal water-referencing method at 3 T and has potential for characterizing lesions for malignancy.

OBJECTIVE. Although MRI is the technique of choice for evaluating most soft-tissue masses, CT often provides valuable complementary information. Specifically, there are distinguishing CT characteristics that can suggest a specific diagnosis, including the lesion's mineralization pattern, density, pattern of adjacent bone involvement, and degree and pattern of vascularity.CONCLUSION. This article provides an overview of the CT evaluation of soft-tissue masses, emphasizing a differential diagnosis based on these CT features.

The objective of this study was to examine the prevalence of incidental shoulder enchondromas on routine magnetic resonance (MR) shoulder imaging. Consecutive routine shoulder MR examinations (N = 477) performed for suspected internal derangement were reviewed for the presence of incidental enchondromas. Incidental enchondromas were detected on 2.1% of routine MR shoulder examinations, the vast majority abutting the physeal plate. This prevalence is important to appreciate, in order to form a meaningful differential diagnosis of pathologic proximal humerus lesions.