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Purpose: To compare magnetic resonance imaging of the ankle joint at 1.5 Tesla (T) and 3.0 T in the assessment of cartilage and ligament pathology in fresh human cadaver specimens., Materials and Methods: The study was performed in line with institutional and legislative requirements; all donors had dedicated their body for educational and research purposes before death. Thirteen fresh human cadaver ankle joints were imaged at 1.5 T and 3.0 T using an optimized clinical ankle protocol consisting of T1-weighted (T1-w), fat-saturated (fs) T2-w, and short tau inversion recovery fast spinecho (FSE) sequences. For dedicated cartilage imaging, fs-intermediate (IM)-w FSE, fs-spoiled gradient echo, and balanced free precession steady state sequences were acquired. Artificial cartilage and ligament lesions were created in 6 and 5 specimens, respectively. MR imaging was repeated in those ankles. Four radiologists independently assessed pathology in all image datasets. Macroscopic findings after dissection served as a reference standard., Results: Sensitivities and ROC-values were higher at 3.0 T for detecting cartilage pathology (sensitivity up to 0.71 at 3.0 T vs. 0.49 at 1.5 T; AZ up to 0.88 vs. 0.74; both differences P < 0.05) and highest for the fs-IM FSE sequence at 3.0 T. Average sensitivity for detecting ligament pathology was higher at 3.0 T (0.69 vs. 0.50; P < 0.05). Specificity was high among all protocols and both field strengths for assessing ligament and cartilage pathology (>0.95)., Conclusion: Compared with 1.5-T imaging, the 3.0-T imaging of the ankle joint at improved diagnostic performance in assessing cartilage significantly and there was a higher sensitivity for assessing ligamentous pathology.

Purpose: To determine the prevalence of pathologic findings in asymptomatic knees of marathon runners before and after a competition in comparison with physically active subjects. To compare the diagnostic performance of cartilage-dedicated magnetic resonance imaging (MRI) sequences at 3.0 T., Materials and Methods: Ten marathon runners underwent 3.0 T MRI 2-3 days before and after competition. Twelve physically active asymptomatic subjects not performing long-distance running were examined as controls. Pathologic condition was assessed with the whole-organ magnetic resonance imaging score (WORMS). Cartilage abnormalities and bone marrow edema pattern (BMEP) were quantified. Visualization of cartilage pathology was assessed with intermediate-weighted fast spin-echo (IM-w FSE), fast imaging employing steady-state acquisition (FIESTA) and T1-weighted three-dimensional (3D) high-spatial-resolution volumetric fat-suppressed spoiled gradient-echo (SPGR) MRI sequences., Results: Eight of ten marathon runners and 7/12 controls showed knee abnormality. Slightly more and larger cartilage abnormalities, and BMEP, in marathon runners yielded higher but not significantly different WORMS (P > 0.05) than in controls. Running a single marathon did not alter MR findings substantially. Cartilage abnormalities were best visualized with IM-w FSE images (P < 0.05)., Conclusion: A high prevalence of knee abnormalities was found in marathon runners and also in active subjects participating in other recreational sports. IM-w FSE sequences delineated more cartilage MR imaging abnormalities than did FIESTA and SPGR sequences.

The objective of this study was to optimize ankle joint MR imaging in volunteers at 1.5 Tesla (T) and 3.0 T, and to compare these optimized sequences concerning image quality and performance in assessing cartilage, ligament and tendon pathology in fresh human cadaver specimens. Initially our clinical ankle protocol consisting of T1-weighted (-w), fat-saturated (fs) T2-w, and short tau inversion-recovery fast spinecho (FSE) sequences was optimized at 1.5 T and 3.0 T by two radiologists. For dedicated cartilage imaging, fs-intermediate (IM)-w FSE, fs spoiled gradient echo, and balanced free-precession steady-state sequences were optimized. Using the optimized sequences, thirteen cadaver ankle joints were imaged. Four radiologists independently assessed these images concerning image quality and pathology. All radiologists consistently rated image quality higher at 3.0 T (all sequences p<0.05). For detecting cartilage pathology, diagnostic performance was significantly higher at 3.0 T (ROC-values up to 0.93 vs. 0.77; p<0.05); the fs-IM FSE sequence showed highest values among the different sequences. Average sensitivity for detecting tendon pathology was 63% at 3.0 T vs. 41% at 1.5 T and was significantly higher at 3.0 T for 2 out of 4 radiologists (p<0.05). Compared to 1.5 T, imaging of the ankle joint at 3.0 T significantly improved image quality and diagnostic performance in assessing cartilage pathology.

Objective: The objective of this study was to characterize the different causes of prolonged sternal pain following thoracic trauma with involvement of the sternum and to define criteria for sternal nonunion diagnosis using MRI., Design and Patients: Five patients with abnormalities of the sternum were evaluated for prolonged sternal pain following thoracic trauma using MRI. MR images were evaluated by two radiologists in consensus. The patients were selected from the radiology database, which included 8 patients with post-traumatic prolonged sternal pain., Results: Two patients (n = 2) revealed a sternal nonunion after sternal fracture. One patient had a sternal fracture with delayed union and minor displacement of the sternal halves. Abnormal signal intensity alterations adjacent to and within the manubrio-sternal joint were evident in 2 patients and considered due to trauma-related changes in the manubrio-sternal joint. The 3 patients who were not included in the study had no abnormalities of the sternum: 1 of them proved to have a well-healed sternal fracture and nonunion of a rib fracture, 1 had subtle Tietze's syndrome, and 1 patient revealed no pathological findings on imaging., Conclusion: Various factors may be responsible for prolonged sternal pain following thoracic trauma, and these can be viewed with MRI. In cases of sternal nonunion there was common fluid-like signal in the fracture interspace between the bony edges, and the bone marrow adjacent to the nonunion showed altered signal intensity. MRI identified sternal nonunion and other trauma-related abnormalities of the sternum following chest trauma.

For decades, fluoroscopic arthrography was the only method available to image a joint with contrast enhancement. Advances in CT led to the natural development of CT arthrography. Development of MRI and its capability for multiplanar imaging led to direct magnetic resonance arthrography (MRA). This technique has been performed since 1987 and has surpassed CT arthrography in popularity in the United States. Indirect MRA developed subsequently to offer a less invasive alternative. This article presents an overview of direct MRA and addresses joint-specific issues regarding direct MRA. An overview of indirect MRA also is provided.

Purpose: To compare 1.5- and 3.0-T magnetic resonance (MR) images of porcine knee specimens containing artificial cartilage lesions in terms of accuracy of lesion depiction, image quality, and signal-to-noise ratio (SNR)., Materials and Methods: This Health Insurance Portability and Accountability Act-compliant study had institutional review board approval, and informed consent was obtained from the human volunteers. Two fat-saturated cartilage MR imaging sequences (an intermediate-weighted fast spin-echo [SE] sequence and a spoiled gradient-echo [GRE] sequence) were optimized for imaging at 3.0 T in two human volunteers and then used to image 10 porcine knees in which 29 artificial cartilage lesions had been created. Corresponding sequences were used at 1.5 T for all specimens. Images were assessed by two radiologists in consensus, and diagnostic performance in lesion depiction was determined by using macroscopic findings in specimen slices as a reference standard. SNRs were also calculated. For statistical analysis, the McNemar test of discordant pairs was used with a level of significance of P < .05., Results: The best diagnostic performance for both the intermediate-weighted fast SE and the spoiled GRE sequences was achieved at 3.0 T. With use of corresponding fat-saturated intermediate-weighted fast SE sequences with an identical acquisition time (9 minutes 44 seconds), 26 (90%) of 29 lesions were detected at 3.0 T, while 18 (62%) were detected at 1.5 T. With use of fat-saturated spoiled GRE sequences, 24 (83%) of 29 lesions were detected at 3.0 T (acquisition time, 8 minutes 48 seconds), and 23 (79%) lesions were detected at 1.5 T (acquisition time, 11 minutes 14 seconds). The rate of correct lesion grade assessment was 65% (17 of 26 lesions) at 3.0 T and 61% (11 of 18 lesions) at 1.5 T with the intermediate-weighted fast SE sequences and 83% (20 of 24 lesions) at 3.0 T and 70% (16 of 23 lesions) at 1.5 T with the spoiled GRE sequences. Both subjective evaluation of image quality and SNR values were significantly higher at 3.0 T (P < .05)., Conclusion: In this animal model, MR imaging at 3.0 T increased the accuracy of cartilage lesion assessment when compared with imaging at 1.5 T. Image quality and SNR were highest at 3.0 T., (Copyright RSNA, 2005)

Objective: The purpose of our study was to determine the optimal concentration of a gadolinium-based contrast agent (gadodiamide) for direct MR arthrography at 3 T compared with 1.5 T in an in vitro study., Conclusion: Optimized concentrations of gadolinium-based contrast agents for MR arthrography are similar at 3 and 1.5 T, although a slightly greater dilution may be useful at 3 T. Signal-to-noise ratio peak levels are significantly reduced by adding an iodinated contrast agent, relatively significantly more at 3 T than at 1.5 T.

Objective: Our objective was to evaluate if whole-body PET with FDG is able to detect bone marrow involvement in patients with multiple myeloma and to assess its appearance and distribution pattern., Materials and Methods: Seventeen whole-body FDG PET scans were performed in 13 patients with multiple myeloma. Four patients were referred for evaluation of extent of disease pretherapy and nine patients were referred for assessment of therapy response (chemotherapy, radiation therapy, bone marrow transplant). FDG PET images were evaluated for distribution and uptake pattern. Standardized uptake values were obtained to quantify FDG uptake. Results of other imaging examinations (MRI, CT, radiography), laboratory data, biopsies, and the clinical course were used for verification of detected lesions., Results: FDG PET was able to detect medullary involvement of multiple myeloma. There were two false-negative results. In one patient, the radiographic skeletal survey showed subcentimeter lytic lesions within the ribs that were not detected on FDG PET and in the other patient, a lytic lesion detected on radiographs showed only mildly increased FDG uptake that was not identified prospectively. There was one false-positive FDG PET result in a patient who had undergone radiation therapy 3 weeks before PET. FDG PET was helpful in differentiating between posttherapeutic changes and residual/recurrent tumor and in assessing response to therapy. FDG PET resulted in upstaging of disease in four patients, which influenced subsequent management and prognosis. Sensitivity of FDG PET in detecting myelomatous involvement was 85% and specificity was 92%., Conclusion: FDG PET is able to detect bone marrow involvement in patients with multiple myeloma. FDG PET is useful in assessing extent of disease at time of initial diagnosis, contributing to staging that is more accurate. FDG PET is also useful for evaluating therapy response.

Tendon injuries about the elbow are among the most commonly encountered pathology in this articulation. These injuries are often the result of chronic repetitive microtrauma but can be seen in the setting of acute trauma. This article focuses on the imaging diagnosis of tendon pathology in the elbow and the associated findings that can be seen with tendon injury. A detailed understanding of common pathology and patterns of injury can facilitate the ease and accuracy of imaging diagnosis.

Objective: To use high-resolution magnetic resonance imaging (MRI) to determine the relationship between articular cartilage degeneration and trabecular bone changes of the femur, condyles and tibia in human knees with osteoarthritis (OA)., Methods: Subjects were divided into three groups: without OA (OA0), mild OA (OA1) and severe OA (OA2). Sagittal images of the knee (0.234 x 0.234mm2, 2-mm slice thickness) were obtained at 1.5T and used for calculating the volume and thickness of the femoral and tibial cartilage. Axial images (0.195 x 0.195mm2, 1-mm slice thickness) were used for calculating the trabecular bone structure parameters: apparent bone volume fraction, trabecular number, trabecular separation and trabecular thickness., Results: Cartilage volume and thickness were less in patients with OA compared to normal controls (P<0.1). Articular cartilage thinning is associated with bone structure loss in the opposite femoral condyle (P<0.05). In varus OA, there were extensive correlations between medial tibia and medial femoral cartilage degeneration, and loss of bone structure in the lateral tibia and lateral condyle. Additional correlations existed between the compartmental differences (lateral minus medial) of cartilage thickness and bone structure., Conclusion: Degradation of articular cartilage within a compartment correlates with a loss of bone structure in the opposite compartment. The correlation between the (L-M) differences corroborates this relationship. Malalignment of the knee due to cartilage degeneration is associated with bone formation in the diseased condyle and bone resorption in the opposite compartment.

Objective: Our objective was to describe the radiologic appearances of calcification of the lateral collateral ligament (LCL) of the knee in four patients who presented with acute atraumatic lateral knee pain. This rare abnormality has not, to our knowledge, been previously shown on MR imaging., Conclusion: Calcification of the LCL of the knee is a rare cause of lateral knee pain and is thought to reflect underlying hydroxyapatite deposition. On MR imaging, calcification of the LCL may be associated with an aggressive appearance that can be mistaken for other knee abnormalities.

Objective: Our objective was to review the imaging features of pseudoaneurysms of the hand in 25 patients. The patients presented with a mass, peripheral paresthesia, or ischemia. Pseudoaneurysm of the hand is a rare and often clinically unsuspected diagnosis. Correct diagnosis is important because there are risks for distal embolic disease with ischemia or gangrene of the fingers, ulnar or digital nerve dysfunction, rupture, or bone erosion and joint destruction. Scant reports appear in the world literature, and this report is the first review, to our knowledge, of the imaging features. The cause may be a history of a single direct trauma or chronic trauma, as seen in patients with hypothenar or thenar hammer syndrome., Conclusion: Awareness of the specific imaging appearances of pseudoaneurysms of the hand and their complications may improve the accuracy of radiologic diagnosis, advance the preoperative workup, and prevent possible clinical complications such as digital gangrene, nerve dysfunction, and aneurysm rupture.

Objective: To use high-resolution magnetic resonance imaging (MRI) to evaluate the trabecular bone structure in the distal femur and the proximal tibia and its to correlate the findings with different stages of osteoarthritis (OA) of the human knee., Methods: Axial images of the distal femur and proximal tibia were obtained at 1.5 T in patients without and with mild OA and with severe OA. The spatial resolution was 195 x 195 microm(2) with a 1-mm slice thickness. Apparent measures of trabecular bone volume fraction (BV/TV), trabecular number (Tb.N), trabecular separation (Tb.Sp), and trabecular thickness (Tb.Th) were calculated., Results: Significant differences existed in the trabecular bone structure of the femur and tibia. Differences in trabecular bone structure between the tibia and the femur decreased with the degree of OA. The apparent BV/TV, Tb.N, and Tb.Sp in the femoral condyles could be used to differentiate healthy patients or patients with mild OA from patients with severe OA (P < 0.05). Among individuals, the structural variation of the lateral and medial femoral condyle was indicative of the extent of the disease., Conclusion: High-resolution MRI of the knee joint can provide a noninvasive assessment of trabecular bone structure. Trabecular bone structure, determined by high-resolution MRI, shows significant variation in patients with varying degrees of OA. The impact of OA on trabecular bone is different in the tibia than in the femur, and this difference depends on the extent of the disease.

We report a case of primary leiomyosarcoma in the right femoral diaphysis. Conventional radiographs revealed an indistinct osteolytic lesion with a very subtle periosteal reaction. MR imaging revealed an intramedullary lesion with a well-defined margin, cortical breakthrough and soft tissue extension. The lesion was isointense relative to muscle on T1-weighted imaging, iso-hypointense relative to fat on fast spin echo T2-weighted imaging, and hyperintense to muscle on fast spin echo T2-weighted imaging with fat saturation. A peripheral rim and intratumoral spoke-wheel-like enhancement in the soft tissue component of the tumor was noted on gadolinium-enhanced T1-weighted imaging with fat saturation. Such an enhancing pattern, which has not been described in the literature previously but has been seen in leiomyosarcomas elsewhere by both MR imaging and computed tomography, deserves further pathological correlation.

Primary osteoarthritis (OA) of the hip has a distinct etiology and epidemiology compared with other types of arthropathy in the hip joint. Arthritis of the hip can be secondary to conditions such as osteonecrosis, trauma, sepsis, or rheumatoid arthritis. Certain conditions, such as congenital hip disease and slipped capital femoral epiphysis, involve predisposing anatomic abnormalities; in such cases, the term "secondary OA" is used. When either an anatomic abnormality cannot be determined or other specific causative entities are not identified, primary OA is the diagnosis of exclusion. The prevalence of hip OA is about 3% to 6% in the Caucasian population and has not changed in the past four decades. In contrast, studies in Asian, black, and East Indian populations indicate a very low prevalence of hip OA. Statistics on patients who underwent total hip replacement for primary OA in San Francisco and Hawaii demonstrate a virtual absence of the condition in Asians and low rates in the black and Hispanic populations. Family studies from Sweden, Britain, and the United States show increased rates of hip OA in first-degree relatives of the index patient when compared with the normal population. Occupations requiring heavy lifting, farming, and elite sports activity are associated with increased rates of hip OA. The low prevalence of hip OA in Asian and black populations in their native countries; the low incidence of total joint replacement for primary OA in Asian, black, and Hispanic populations in North America; and the familial association of hip OA in Caucasians all suggest that genetic factors may be involved in the occurrence of this disease.

Objective: The objective of this study was to review the imaging appearance of the femurs of five patients who had been referred from outside institutions after presenting with thigh pain and being given a preliminary diagnosis of primary malignant bone tumor. Typically, when making a diagnosis, physicians place emphasis on the characteristic appearances of diseases on MR imaging, but such appearances may be misleading. An awareness of the specific MR imaging pattern of stress-related partial muscle avulsion can lead to the correct diagnosis., Conclusion: Femoral diaphyseal periostitis after a sports injury to the adductor musculature in children has a characteristic imaging appearance. This condition can initially appear to be misleadingly aggressive. Knowledge of the findings-particularly of the findings on MR imaging-in the proper clinical setting can help physicians make the correct diagnosis and eliminate unnecessary biopsy or inappropriate treatment.

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease is widespread in elderly persons and has various clinical presentations that can be confounding to clinicians. It is characterized by acute, subacute, or chronic joint inflammation and deposition of CPPD crystals in hyaline cartilage, fibrocartilage, and other soft tissue structures. We have learned a great deal about imaging findings of CPPD crystal deposition disease. New facts about the disorder and clues to radiologic diagnosis continue to be revealed. This article will provide a review of imaging characteristics of this disease with emphasis on some recent findings. The nomenclature, epidemiology, classification, and pathophysiology will be explained. A discussion of the clinical manifestations and treatment will be followed by a review of the characteristic imaging features.

This article reviews three topics of fundamental importance in MR imaging of degenerative diseases in the cervical spine: (1) common clinical presentations that determine whether an MR examination is ordered and the ultimate significance ascribed to MR imaging results; (2) imaging techniques; and (3) MR imaging of the major types of cervical spine degeneration.

Purpose: To investigate the histopathologic anatomy of calcium pyrophosphate dihydrate (CPPD) crystal deposition in and around the atlantoaxial joint and the association between CPPD crystal deposition and subchondral cysts, erosions, and fracture involving the odontoid process of the axis., Materials and Methods: One adult cadaver demonstrating calcification in the retro-odontoid area at computed tomography (CT) was selected for further radiography, CT, and magnetic resonance (MR) imaging at the C1-2 level. Anatomic sectioning and histologic evaluations were performed in the specimen. For clinical study, radiographs (n = 5), CT scans (n = 8), and MR images (n = 6) in nine patients (mean age, 74.4 years) with odontoid process fractures and CPPD crystal deposits in and around the atlantoaxial joint were reviewed., Results: In the cadaveric specimen, radiography and CT demonstrated calcifications in the transverse ligament; histologic evaluation confirmed that these calcifications were CPPD crystal deposits. In all nine patients, radiography (n = 5) and CT (n = 8) also showed calcification in areas adjacent to the odontoid process, which included the transverse ligament. T1- and T2-weighted MR imaging showed a retro-odontoid mass of low signal intensity that compressed the cervical cord in six patients. CT, MR imaging, or both demonstrated subchondral cysts, osseous erosions, or a type 2 odontoid fracture in all patients., Conclusion: CPPD crystal deposition disease involving the C1-C2 articulation can be a clinically important entity that may place affected patients at increased risk of pathologic fracture of the odontoid process.

Objective: We describe the MR anatomy of the subcoracoid bursa and findings associated with subcoracoid effusion., Conclusion: Fluid in the subcoracoid space, revealed on MR imaging of the shoulder, may lie in the subcoracoid bursa or the subscapularis recess (both structures can be distinguished with MR imaging). In our patients, subcoracoid effusions were often associated with anterior rotator cuff tears, including tears of the rotator interval.

The foot is an uncommon location for chondrosarcoma. The presentation, diagnosis, pathological findings, surgical treatment and follow-up of three patients with chondrosarcoma in this rare location are presented. Though nonspecific, MR imaging findings were of aid in the diagnosis and treatment planning of these patients. If the diagnosis of this tumor is rapidly made, a tumor excision instead of limb amputation may be sufficient treatment at surgery.

Elbow arthrography provides useful information that is not available with noninvasive imaging. This article describes normal elbow anatomy as seen by arthrography. Technical aspects of arthrography with regard to radiographs and CT and MR imaging are reviewed. Indications for MR arthrography include identification of loose bodies, chondral and osteochondral fractures, collateral ligament tears, and synovial and capsular abnormalities.

Our understanding of shoulder disorders has changed considerably as a result of improved diagnostic tools, such as arthroscopy and multiplanar imaging modalities. The diagnosis of the cause of shoulder pain can be difficult because a spectrum of disorders, including cervical spine disease, acromioclavicular arthritis, and shoulder instability. Impingement and denervation syndromes can present with similar clinical findings. Accurate depiction of anatomic abnormalities is important for treatment planning. The purpose of this article is to report on the application of available imaging modalities, with emphasis on MR imaging. A strategy for the appropriate use of these studies and their variations of technique is also provided.

MR imaging is useful in the evaluation of benign and malignant osseous and soft-tissue masses in the elbow. It allows for multiplanar, high-contrast images that provide precise definition of local tumor extent. The paucity of fat and a high concentration of small soft-tissue structures such as tendons, ligaments, and nerves in this area makes MR imaging more advantageous than CT for delineating tumor margins in the soft tissue. This article describes some of the more common tumors around the elbow with emphasis on their MR imaging characteristics.

MR imaging provides clinically useful information in assessing the elbow joint. Superior depiction of muscles, ligaments, and tendons as well as the ability to visualize nerves, bone marrow, and hyaline cartilage directly are advantages of MR imaging relative to conventional imaging techniques. These features of MR imaging may help to establish the cause of elbow pain by accurately depicting the presence and extent of bone and soft-tissue pathology. Ongoing improvements in surface coil design and newer pulse sequences have resulted in higher quality MR images of the elbow that can be obtained more rapidly. Recent clinical experience has shown the utility of MR imaging in detecting and characterizing disorders of the elbow in a noninvasive fashion.

Objective: The purpose of this study was to show the MR arthrographic imaging features of a normal anatomic variation of the shoulder: the absence of the anterior superior labrum and the presence of a "cordlike" middle glenohumeral ligament,which together are known as the Buford complex., Materials and Methods: We retrospectively analyzed the MR arthrographic examinations of 10 patients with arthroscopically proven Buford complexes., Results: MR arthrographic examinations showed an absent anterior superior labrum and an associated cordlike middle glenohumeral ligament in all patients. No contiguous tear of the superior labrum or anterior inferior labrum was evident. Originally, this variation was mistakenly diagnosed as a labral avulsion in two of the 10 patients. Also, a differential diagnosis of a superior labral tear was mistakenly offered for four patients., Conclusion: An absent anterior superior labrum and an associated cordlike middle glenohumeral ligament represent the normal variation that is known as the Buford complex rather than an avulsed labrum. This normal variation may be mistaken for a detached labrum.

Magnetic resonance imaging provides clinically useful information in assessing the elbow joint. Superior depiction of muscles, ligaments, and tendons as well as the ability to directly visualize nerves, bone marrow, and hyaline cartilage are advantages of magnetic resonance imaging relative to conventional imaging techniques. Ongoing improvements in surface coil design and newer pulse sequences have resulted in higher quality magnetic resonance images of the elbow. Traumatic and degenerative disorders of the elbow are well seen with MR imaging. The sequelae of medial traction and lateral compression from valgus stress include medial collateral ligament injury, common flexor tendon pathology, medial traction spurs, ulnar neuropathy, and osteochondritis dissecans. These conditions as well as lateral collateral ligament injury and lateral epicondylitis may be characterized with magnetic resonance imaging. Posttraumatic osseous abnormalities well seen by magnetic resonance imaging include radiographically occult fractures, stress fractures, bone contusions, and apophyseal avulsions. Magnetic resonance imaging also can be used to assess cartilaginous extension of fractures in children. Intraarticular loose bodies can be identified with magnetic resonance imaging, especially if fluid or contrast material is present within the elbow joint. Biceps and triceps tendon injuries can be diagnosed and characterized. Magnetic resonance imaging also can provide additional information regarding entrapment neuropathies about the elbow. Magnetic resonance imaging is perhaps most useful when patients have not responded to conservative therapy and therefore surgery and additional diagnoses are being considered.

Para-articular cysts frequently are seen on routine imaging examinations. They may be clinically asymptomatic or may cause pain, swelling, or impaired joint function. They often are associated with underlying joint disorders, such as trauma, degeneration, or inflammation. This article discusses the cause, symptoms, and appearance of para-articular cysts on various imaging examinations including arthrography, ultrasound, CT scan, and MR imaging. Specific attention is focused on those cystic masses appearing around the hip, knee, ankle and foot, shoulder, elbow, wrist and hand, spine, temporomandibular joints, and periosteum.

Elastofibroma is a rare, benign soft-tissue tumor that occurs along the chest wall in the periscapular region. We identified five patients with a surgical diagnosis of elastofibroma who had had CT and/or MR scans. CT and MR imaging were compared to histologic findings in two patients. CT was available in three patients and demonstrated periscapular soft-tissue tumor with an attenuation similar to that of adjacent muscle. In one patient, the tumors appeared homogeneous. In two patients, the tumor showed strands of low density similar to that of adjacent subcutaneous fat on CT. On MR imaging, all five tumors showed predominantly low-signal intensity on both T1 and T2-weighted images. The tumors contained focal areas with high-signal intensity on T1-weighted scans that showed intermediate to high-signal intensity with T2-weighting. The areas of low-signal intensity on both T1 and T2-weighted images corresponded histologically to fibroelastic tissue. The areas of high signal intensity on T1-weighting and intermediate to high-signal intensity on T2-weighting reflected focal areas of fat within the tumor. Although CT and MR imaging findings are not specific, the presence of a soft-tissue tumor along the chest wall in a periscapular location that shows predominantly low intensity on all sequences reflecting fibrous tissue with interspersed focal areas of fatty tissue is highly suggestive of elastofibroma.

Purpose: To determine the utility of magnetic resonance (MR) imaging and MR arthrography in the evaluation of arthroscopic findings of posterosuperior glenoid impingement., Materials and Methods: The findings at MR imaging, MR arthrography, and physical examination with the patient under anesthesia were retrospectively reviewed in eight patients with arthroscopic evidence of posterosuperior glenoid impingement., Results: All patients had shoulder pain; anterior instability was found in six patients. Other than bone marrow abnormalities, findings at MR imaging were not reliable for the detection of posterosuperior glenoid impingement. MR arthrography was superior to routine MR imaging in all four cases in which it was done; positioning the shoulder in abduction and external rotation was beneficial in three of four patients., Conclusion: Impingement of the rotator cuff on the posterior superior glenoid labrum is a cause of posterior shoulder pain in athletes who throw. MR arthrography may allow detection of abnormalities associated with this clinical entity.

Numerous recent technical innovations in magnetic resonance imaging have dramatically improved the imaging evaluation of musculoskeletal disease; however, with the introduction of new techniques comes the risk of inappropriate applications and unanticipated pitfalls in interpretation. Some of the practical and theoretical implications of these recent innovations as well as potential caveats associated with their use are highlighted in the following discussion.

Glucocorticoid administration is a well established cause of osteopenia. Mechanisms underlying the deleterious effect of glucocorticoids on bone may include direct inhibition of bone formation as well as indirect effects through changes in intestinal calcium absorption, renal calcium excretion, and/or levels of the calciotropic hormones. To further examine the potential role of the calciotropic hormones we measured serum levels of PTH and 1,25 dihydroxyvitamin D [1,25(OH)2D], as well as serum and urine levels of calcium and vertebral bone density in patients with chronic obstructive pulmonary disease being managed with or without prednisone. Patients treated with prednisone had lower spinal bone density (53 vs. 106 mg/cm3) and higher serum calcium (2.40 vs. 2.33 mmol/l), urine calcium (6.9 vs. 2.7 mmol/24h), and 1,25(OH)2D levels (147 vs. 95 pmol/L). Compared to the patients not treated with glucocorticoids. PTH levels also tended to be higher (33 vs. 26 microliters-eq/ml), but the difference was not significant. Serum and urine calcium levels correlated positively with 1,25(OH)2D levels, but none of these measurements correlated with PTH levels. Our results suggest that prednisone treatment alters the regulation of 1,25(OH)2D production, and this may contribute to the loss of bone mineral induced by prednisone.

MR imaging has been shown to be accurate in the diagnosis of rotator cuff disruption and tear. Uncertainty remains about the significance of increased signal intensity in the critical zone of the supraspinatus tendon without visible disruption of tendon fibers and about the significance of other secondary findings commonly encountered with rotator cuff abnormalities, such as musculotendinous retraction or obliteration and fluid in the subacromial space. We evaluated proton density-weighted and T2-weighted coronal images (obtained on a 1.5-T superconductive MR imager) of 55 shoulders in 32 asymptomatic volunteers for signal intensity in the supraspinatus tendon, location of the musculotendinous junction, fluid in the subacromial-subdeltoid space, and appearance of the fat plane. In 89% of shoulders, the supraspinatus tendon showed focal, linear, or diffuse increased signal intensity with or without loss of the low-signal-intensity tendon margin on proton density-weighted images. None of these findings were confirmed on T2-weighted images. The musculotendinous junction was always located within an area 15 degrees medial to 30 degrees lateral to the highest point (12 o'clock) on the humeral head convexity. A peribursal fat plane was poorly defined or absent in 49%, and fluid in the subacromial-subdeltoid space was found in 20%. Increased signal intensity in the supraspinatus tendon on proton density-weighted images without a corresponding increase on T2-weighted images, the presence of small amounts of fluid in the subacromial space, and the lack of preservation of the subdeltoid fat plane are common findings in asymptomatic shoulders and by themselves are poor predictors of rotator cuff disease.

The purpose of this study was to describe MR findings in full-thickness tears of the rotator cuff. Of 102 shoulders examined by MR imaging, 31 were found to have a full-thickness tendon tear at arthroscopy/bursoscopy (five shoulders) or open surgery (26 shoulders). All shoulders were imaged in oblique coronal and axial planes. MR images of the 102 shoulders were evaluated for (1) the presence of fluid in the subacromial and subdeltoid bursae; (2) abnormal signal of the supraspinatus, subscapularis, infraspinatus, and teres minor tendons; (3) interruption of tendon continuity and thinning of the tendon; and (4) proximal retraction of the junction of the muscle and tendon. The presence or absence of each finding was determined by consensus of two radiologists, who interpreted the images without knowledge of the surgical findings. Results in those 31 shoulders with proved full-thickness tears were: fluid in the subacromial bursae (29 shoulders), interruption of tendinous continuity (22 shoulders), focally increased signal of the tendon equivalent to that of water (27 shoulders), and musculotendinous retraction (24 shoulders). The finding of subacromial fluid was a sensitive indicator (93%) of a full-thickness tear, and interruption of tendinous continuity was a specific finding (96%) in diagnosing a full-thickness tear. Our experience shows interruption of tendon continuity is the most specific MR finding of full-thickness rotator cuff tears, while subacromial fluid is the most common finding.

Conventional imaging of the wrist has relied heavily on plain radiography, tomography, fluoroscopy and arthrography. More recently, computed tomography and magnetic resonance imaging (MRI) have been added to this armamentarium. In this article the authors review the normal anatomy of the wrist and demonstrate a variety of pathologic conditions that can be assessed with MRI, including avascular necrosis and tears of the intrinsic and the extrinsic ligaments and the triangular fibrocartilage. MRI of the wrist is still evolving rapidly, and its place in the work-up of wrist disorders is only now being defined.

Thirty-two patients with clinical suspicion of shoulder instability were the subject of this assessment of MRI (1.5 T G. E. Signa) and its comparison with CT-arthrography (GE8800 and GE9800) of the shoulder. Twenty-seven patients had a final diagnosis established by arthroscopy and five by arthrotomy. The imaging examinations were interpreted independently by three radiologists blinded against history, surgical diagnosis and results of the compared test. The statistical analysis included ROC-curves, sensitivity, specificity and accuracy as well as predictive values. The significance of the comparative results was assessed by the McNemar Sign test. MRI showed significantly better diagnostic results in the evaluation of labral structures (sensitivity 85%, specificity 90%, accuracy 88%) and humeral head impression fractures (75, 82, 78 %). None of the tests were of sufficient diagnostic value to identify capsular abnormalities. CT and MRI results regarding the biceps tendon and loose bodies were similar, however, statistically not significant. MRI proved to be of high diagnostic value in the assessment of the unstable shoulder and compared favorably with CT-A.

Spindle cell hemangioendothelioma is a slowly progressing vascular tumor of low grade malignancy. This neoplasm has been reported in 33 patients but in only one patient were osseous lesions seen. The only other description regarding imaging of this tumor was CT demonstrating soft tissue masses in the thigh without osseous involvement. We present a case of spindle cell hemangioendothelioma in which magnetic resonance further defined the radiographic features of this newly recognized tumor.

To identify the magnitude of muscle hypertrophy following electrically stimulated exercise in paraplegic subjects, we used quantitative CT (QCT) of the midthigh prior to and following 6 weeks of bicycle ergometry. Three patients who had suffered acute spinal cord injury were examined in this pilot investigation. Average absolute changes in muscle cross-sectional area by QCT were determined to be 10.6 cm2 (p = 0.042) at a distal site located 100 mm above the tibial plateau and 18.8 cm2 (p = 0.019) at a more proximal site (175 mm). Expressed as a percentage increase, these changes were likewise found to be significant. When the total thigh musculature was segmented into anterior and posterior regions, significant increases were observed only among the anterior muscle groups at both the distal and the proximal sites. Muscle hypertrophy as determined by standard anthropometric techniques at 200 mm above the patella was not found to be significant. We conclude that QCT is a valuable technique for discerning changes in muscle size during fitness training and that, in our population, it was capable of differentiating specific muscle compartment hypertrophy secondary to electrical stimulation.