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No substitute exists for a thorough hands-on examination when a patient presents with a musculoskeletal problem. For those times when you need MRI for a management decision, here is a useful guide. [ABSTRACT FROM AUTHOR]

No substitute exists for a thorough hands-on examination when a patient presents with a musculoskeletal problem. For those times when you need MRI for a management decision, here is a useful guide. [ABSTRACT FROM AUTHOR]

Superior labral anterior and posterior lesions and long head biceps injury are 2 common sources of shoulder pain. The presenting complaints and physical examination findings for these etiologies are often nonspecific, making diagnosis challenging. Further complicating their diagnoses, these 2 pathologies often cooccur together or with other shoulder pathologies such as subacromial bursitis, rotator cuff tear, and shoulder instability. However, with advancement in magnetic resonance imaging and shoulder arthroscopy techniques the ability to diagnose and treat these pathologies has vastly improved over the past 30 years. This review provides a case-based description of the correlation between magnetic resonance imaging and arthroscopic findings in common superior labral anterior and posterior and long head biceps injury, accompanied with current management strategies.

Although posttraumatic pelvic heterotopic ossification (HO) after hip fracture dislocation is well established, and nerve encasement by HO may occur, the development of neurologic deficit is rare. A thorough history and adequate clinical suspicion are imperative in the workup of affected patients. Computed tomography and magnetic resonance imaging provide good visualization and assist in surgical planning. If symptoms persist and are recalcitrant to conservative management, surgical intervention with HO excision and nerve neurolysis can be performed with success.

Objective: The purpose of this study was to evaluate the diagnostic accuracy of 3-T MRI versus 3-T MR arthrography for assessing labral abnormalities in the shoulder using arthroscopy as the gold standard., Subjects and Methods: Forty-two patients (28 men, 14 women; mean age, 33 years) underwent MR arthrography and conventional MRI of the same shoulder. Two patients underwent bilateral shoulder examinations, for a total of 44 shoulder examinations. Twenty-two shoulders underwent arthroscopy. The results of arthroscopy were used as the reference standard. Three musculoskeletal radiologists prospectively and independently interpreted MRI and MR arthrography examinations. Differences in performance of conventional MRI and MR arthrography were analyzed for statistical significance by the two-tailed McNemar test., Results: Of the 22 arthroscopies performed, 26 labral tears were found in 18 shoulders and four shoulders were normal with respect to the labrum. There were 12 superior, nine posterior, and five anterior labral tears identified at arthroscopy. By consensus review, conventional MRI identified nine of 12 superior (sensitivity, 75%; specificity, 100%), seven of nine posterior (sensitivity, 78%; specificity, 92%), and three of five anterior (sensitivity, 60%; specificity, 94%) labral tears. MR arthrography identified nine of 12 superior (sensitivity, 75%; specificity, 100%), eight of nine posterior (sensitivity, 89%; specificity, 100%), and five of five anterior (sensitivity, 100%; specificity, 100%) labral tears., Conclusion: Although the power of our preliminary study is small, the results suggest that intraarticular contrast material is helpful in diagnosing labral tears in the shoulder, particularly tears of the anterior labrum. Our preliminary results suggest that MR arthrography adds value for diagnosing labral tears in the shoulder compared with conventional MRI even at 3 T.

Objective: Patients with a known primary malignancy and one or more suspicious skeletal lesions are often assumed to have skeletal involvement by the known malignancy. We set out to determine how often one would be correct in making this assumption., Materials and Methods: All CT-guided bone biopsies performed at our institution between January 2006 and January 2009 in patients with a history of a single biopsy-proven malignancy were retrospectively reviewed. Pathology results were assigned to one of three outcomes: skeletal involvement by known malignancy, newly diagnosed malignancy, or no malignancy identified. Patients categorized as no malignancy identified required repeat biopsy or stability on follow-up imaging for confirmation., Results: Of 104 patients with a known primary malignancy, 11 were excluded. Of the 93 included patients, there was skeletal involvement by the known malignancy in 82 (88%), a newly diagnosed malignancy in seven (8%), and no malignancy identified in four (4%)., Conclusion: Biopsy of a suspicious skeletal lesion in a patient with a solitary known malignancy reveals a newly diagnosed malignancy or no evidence of malignancy in 12% of patients, emphasizing the importance of biopsy.

Objective: Secondary signs have been sought to help in the MR diagnosis of rotator cuff tears, especially partial-thickness tears. We sought to determine whether intramuscular cysts are always present with rotator cuff tears and the types of rotator cuff tears with which they present, and to establish the clinical significance of finding intramuscular cysts., Materials and Methods: Retrospective analysis of our institution's database of 5,101 MRI examinations of the shoulder during an 8-year period resulted in 187 examinations in 185 patients who were thought to have intramuscular cysts. Of the 187 examinations, 134 shoulders in 132 patients (62 women, 70 men) met our criteria for an intramuscular cyst., Results: Of the 134 shoulders with intramuscular cysts, 102 (76.1%) showed imaging findings of both intramuscular cysts and rotator cuff tears. Thirty-two of the 134 (23.9%) shoulders were diagnosed with only an intramuscular cyst and were not associated with a rotator cuff tear. Fifty-five of 102 (53.9%) shoulders consisted of an intramuscular cyst associated with a full-thickness rotator cuff tear, and 47 of 102 (46.1%) shoulders presented with a partial-thickness rotator cuff tear. Forty-eight of 102 (47.1%) shoulders with both an intramuscular cyst and a rotator cuff tear also underwent the reference standard arthroscopy examination to confirm the MRI findings. In 46 of 48 (95.8%) shoulders that underwent arthroscopy, the findings confirmed the imaging evidence; the other two cases were shown to have an intact rotator cuff at arthroscopy., Conclusion: Our study echoes the findings of previous studies that suggest a relationship between intramuscular cysts and full- and partial-thickness rotator cuff tears but illustrates that the incidence of an isolated intramuscular cyst is higher than previously expected. When intramuscular cysts present with rotator cuff tears, they present with full- and partial-thickness rotator cuff tears in relatively equal proportions. The presence of an intramuscular cyst on MRI, although it may be an isolated finding, should prompt a thorough search of all the rotator cuff tendons for tears so that the patient may receive appropriate follow-up.

Objective: The purpose of this article is to review the clinical importance and MRI appearances of injuries to the posterolateral corner of the knee., Conclusion: Injuries to the posterolateral corner structures of the knee can cause significant disability due to instability, cartilage degeneration, and cruciate graft failure. Becoming familiar with the anatomy of this region can improve one's ability to detect subtle abnormalities and can perhaps lead to improvements in diagnosing and understanding injuries to this area.

This article outlines a curriculum for resident education in musculoskeletal radiology that addresses the current requirements for assessment of the general competencies as set forth by the Accreditation Council for Graduate Medical Education.

Objective: To identify shoulder magnetic resonance imaging (MRI) findings associated with surgically proven rotator interval abnormalities., Materials and Methods: The preoperative MRI examinations of five patients with surgically proven rotator interval (RI) lesions requiring closure were retrospectively evaluated by three musculoskeletal-trained radiologists in consensus. We assessed the structures in the RI, including the coracohumeral ligament, superior glenohumeral ligament, fat tissue, biceps tendon, and capsule for variations in size and signal alteration. In addition, we noted associated findings of rotator cuff and labral pathology., Results: Three of three of the MR arthrogram studies demonstrated extension of gadolinium to the cortex of the undersurface of the coracoid process compared with the control images, seen best on the sagittal oblique images. Four of five of the studies demonstrated subjective thickening of the coracohumeral ligament, and three of five of the studies demonstrated subjective thickening of the superior glenohumeral ligament. Five of five of the studies demonstrated a labral tear., Conclusions: The MRI arthrogram finding of gadolinium extending to the cortex of the undersurface of the coracoid process was noted on the studies of those patients with rotator interval lesions at surgery in this series. Noting this finding-especially in the presence of a labral tear and/or thickening of the coracohumeral ligament or superior glenohumeral ligament-may be helpful in the preoperative diagnosis of rotator interval lesions.

Objective: The purpose of this study was to determine whether there are identifiable factors that dissuade female medical students from entering the field of radiology., Materials and Methods: An anonymous survey was completed by medical students at the end of their third- or fourth-year radiology clinical clerkships at five institutions. In addition to demographic data and residency choice, respondents ranked 10 factors in order of importance to their choice of career. For respondents who did not consider radiology a possible career, a second set of eight factors was ranked for importance in dissuading them., Results: Two hundred eighty-eight respondents completed the survey, 152 (53%) men and 136 (47%) women. Both men and women reported direct patient contact and intellectual stimulation as the most important factors in deciding on a specialty. For those who chose radiology, intellectual stimulation and use of emerging technology were significantly (p < 0.05) more important than other factors. The factor that most strongly (96%) dissuaded men and women from a career in radiology was lack of direct patient contact. There was no significant difference between men and women in ranking factors that dissuaded them from applying to radiology residencies; however, nearly one third of the female respondents cited competitiveness of the residency process as important., Conclusion: Patient contact remains an important factor for medical students choosing a career. To attract high-caliber students, medical schools should expose students to areas of radiology involving patient interaction. Academically qualified women should be identified early during their careers and encouraged to apply for radiology residencies.

Malignant tumors of the upper extremity are uncommon, and their care should be referred to specialized facilities with experience treating these lesions. The Musculoskeletal Tumor Society (MSTS) staging system is used by the surgeon to determine appropriate surgical management, assess prognosis, and communicate with other healthcare providers. Magnetic resonance imaging (MRI) is employed pre-operatively to identify a lesion's compartment of origin, determine extent of spread, and plan biopsy and resection approaches. Involvement of neurovascular structures may result in devastating loss of upper extremity function, requiring amputation. Violation of high-resistance compartmental barriers necessitates more extensive surgical resection. Biopsy may be performed by the radiologist using imaging guidance. Knowledge of compartmental anatomy allows the radiologist or surgeon to use an easily excisable biopsy approach and prevent iatrogenic spread to unaffected compartments. Case examples are presented to illustrate the importance of compartmental anatomy in the management of benign and malignant upper extremity tumors.

Objective: MRI has historically provided suboptimal visualization of tears of the acetabular labrum. Degenerative fraying and underlying cartilage abnormalities can often mimic tears of the labrum on conventional MRI. Administration of intraarticular gadolinium enhances the MRI appearance of the labrum to improve detection of labral abnormalities. This study examined the improved diagnostic sensitivity of MR arthrography compared with conventional MRI and the importance of confining the study to a small field of view., Materials and Methods: Fifty-one hips were imaged in 48 patients. Fourteen hips underwent conventional MRI with a large field of view (30-38 cm). Seven hips underwent conventional MRI with a small field of view (14-20 cm). Thirty hips underwent MR arthrography with a small field of view (14-20 cm). Labral tears were diagnosed when contrast material was identified within the labrum or between the labrum and the acetabulum, when a displaced fragment was noted, or when a paralabral cyst was identified. All study results were compared with findings at the time of hip arthroscopy., Results: Conventional MRI with a large field of view was 8% sensitive in detecting labral tears compared with findings at the time of arthroscopy. Diagnostic sensitivity was improved to 25% with a small field of view. MR arthrography with a small field of view was 92% sensitive in detecting labral tears., Conclusion: A combination of MR arthrography and a small field of view is more sensitive in detecting labral abnormalities than is conventional MRI with either a large or a small field of view.

Institutional review board approval and informed consent were obtained for this HIPAA-compliant study. The purpose of this study was to prospectively compare imaging of the acetabular labrum with 3.0-T magnetic resonance (MR) imaging and 1.5-T MR arthrography. Eight patients (four male, four female; mean age, 38 years) with hip pain suspicious for labral disease were examined at both MR arthrography and MR imaging. Presence of labral lesions, paralabral cysts, articular cartilage lesions, subchondral cysts, osteophytes, and synovial herniation pits was recorded. There was arthroscopic correlation of findings in five patients. MR imaging depicted four surgically confirmed labral tears that were identified at MR arthrography, as well as one that was not visualized at MR arthrography. MR imaging helped identify all other pathologic conditions that were diagnosed at MR arthrography and helped identify one additional surgically confirmed focal articular cartilage lesion. These results provide encouraging support for evaluation with 3.0-T MR imaging over 1.5-T MR arthrography., ((c) RSNA, 2006)

Objective: Metatarsal stress fractures are common and represent debilitating and potentially season-ending injuries for basketball players. Bone marrow edema is readily visualized on MRI and can be a sign of stress changes. Twenty-six asymptomatic male National Collegiate Athletic Association basketball players were imaged before the 2003-2004 season and 14 players were reimaged after the conclusion of the season with a screening study of long- and short-axis fat-suppressed T2-weighted images (TR/effective TE, 3,500/56) to identify bone marrow edema in the metatarsals., Conclusion: Six (12%) of 52 feet showed a signal indicating bone marrow edema in the metatarsals. MRI depicts bone marrow edema in the feet before a fracture becomes evident. Identification of this edema may reveal stress changes, allowing early treatment and prevention of debilitating stress fractures.

Objective: The coracohumeral interval previously has been described as predictive of subcoracoid impingement on dynamic screening. The purpose of this study was to determine whether a coracohumeral interval acquired from routinely performed MRI can reliably diagnose subcoracoid impingement., Materials and Methods: Preoperative MRI examinations of 19 patients (16 males, three females) with subsequent surgical confirmation of subcoracoid impingement were reviewed retrospectively and compared with MRI studies of 41 control subjects (22 males, 19 females). Axial and oblique sagittal coracohumeral interval measurements were taken. The morphology of the coracoid process and lesser tuberosity was assessed. Postanalysis application of the data to two smaller groups of patients was performed. The first group consisted of nine subjects (three males, six females) for whom subcoracoid impingement was diagnosed prospectively on the basis of abnormalities found by MRI. The second group consisted of seven patients (two males, five females) who were referred for MRI evaluation because of clinically suspected subcoracoid impingement., Results: The average coracohumeral interval for females was 3 mm smaller than that for males. Using sex-adjusted data, we found a statistically significant difference between individuals with or without subcoracoid impingement in the axial coracohumeral interval (p = 0.01). This value, however, was poorly predictive (area under the receiver operating characteristic curve, 0.73). An 11.5-mm axial coracohumeral interval had 84% sensitivity but only 44% specificity. A 10.5-mm axial coracohumeral interval had 79% sensitivity and 59% specificity. The shoulder morphologic features assessed and intraarticular contrast use were not statistically significantly related to the coracohumeral interval. In postanalysis application of data, in the group of nine subjects without clinical diagnosis of subcoracoid impingement, all prospective MRI subcoracoid impingement diagnoses were falsely positive. However, if subcoracoid impingement was the referring diagnosis, prospective MRI evaluation more often was correct (n = 7 [three true-negatives, two true-positives, two false-negatives])., Conclusion: A sex-adjusted coracohumeral interval of 10.5-11.5 mm, although statistically significantly related to subcoracoid impingement, is poorly predictive of this diagnosis when acquired via routinely performed MRI. Subcoracoid impingement is primarily a clinical diagnosis that may be supported, but not established, by this means.

Objective: Internal impingement is a condition that occurs in athletes in which the shoulder is put in extreme abduction and external rotation during overhead movements. During this motion, the posterior fibers of the supraspinatus tendon, anterior fibers of the infraspinatus tendon, or both can get impinged between the humeral head and the posterior glenoid. The purpose of this study was to evaluate the ability of MRI to show the findings of internal impingement of the shoulder., Conclusion: As opposed to our six patients with clinically and surgically diagnosed internal impingement, the control patients had isolated pathology in the rotator cuff, labrum, or humeral head. We found that the constellation of findings of undersurface tears of the supraspinatus or infraspinatus tendon and cystic changes in the posterior aspect of the humeral head associated with posterosuperior labral pathology is a consistent finding diagnostic of internal impingement.

Objective: We compare sensitivities of conventional spin-echo and fast spin-echo sequences in the evaluation of meniscal tears. Furthermore, we reevaluate the results from prior studies comparing these two sequences to understand why there are differing conclusions regarding the efficacy of fast spin-echo sequences as a commensurate replacement for conventional spin-echo sequences., Materials and Methods: We used records from a control group of 64 patients (128 menisci) who had undergone arthroscopy to determine the sensitivity of conventional spin-echo sequences for detecting meniscal tears. Two hundred sixteen consecutive patients (432 menisci) were then imaged using conventional spin-echo and fast spin-echo sequences to evaluate for meniscal tears. Both sequences were proton density-weighted with fat suppression., Results: Of the 432 menisci, 170 tears were detected on conventional spin-echo imaging. Only 128 tears were detected on the fast spin-echo sequence. The sensitivities of conventional spin-echo and fast spin-echo imaging were found to be 93% and 80%, respectively. In addition, findings from conventional spin-echo and fast spin-echo sequences were discordant for 72 menisci (17%, p < 0.01)., Conclusion: The sensitivities of conventional spin-echo and fast spin-echo imaging for detecting meniscal tears have been shown to be greater than 90% and approximately 80%, respectively. However, some authors advocate substituting conventional spin-echo imaging with fast spin-echo imaging. We urge the abandonment of fast spin-echo imaging for evaluating meniscal tears because a loss of greater than 10% in sensitivity is unacceptable.

A thorough understanding of compartmental anatomy is necessary for the radiologist participating in the care of a patient with a lower extremity musculoskeletal malignancy. Localization of tumor to compartment of origin and identification of extracompartmental spread preoperatively are needed to correctly stage a tumor and determine the appropriate surgical management. An understanding of the locations of fascial boundaries, extracompartmental tissues, and neurovascular structures of the thigh and lower leg facilitates this diagnostic process. For the radiologist planning to biopsy a suspicious musculoskeletal lesion, consultation with the referring orthopaedic surgeon is recommended in order to jointly select an appropriate percutaneous biopsy approach. Adequate preprocedural planning ensures selection of an approach which prevents iatrogenic tumor spread beyond the compartment of origin, protects neurovascular structures, and allows complete resection of the biopsy tract and scar at the time of surgical resection without jeopardizing a potential limb-sparing procedure. Cross-sectional anatomic review and case examples demonstrate the importance of a detailed understanding of compartmental anatomy when approaching the patient with a lower extremity musculoskeletal tumor.

Persistent instability or redislocation is uncommon but of significant concern in treating elbow dislocations. Finding an objective, static radiographic sign that might correlate with the presence of instability was the purpose of this study. Pre- and post-reduction radiographs of 10 consecutive simple and complete adult elbow dislocations were reviewed and compared with radiographs of 20 consecutive adult elbows without any trauma history. A statistically significant measured increase in static ulnohumeral distance was noted on the routine unstressed post-reduction lateral radiographs of patients sustaining dislocation. We have termed this increased distance the drop sign. It differs from the radiographic ulnohumeral separation noted during O'Driscoll's test for posterolateral rotary instability, which is present only with axial compression. The drop sign becomes concerning only if persistent after the first reduction radiograph and may be a warning sign of the presence of instability.

Glenoid labral tears exceeding 180 degrees are an uncommon entity in which characteristic clinical and MR imaging features can lead to a more accurate preoperative diagnosis. We provide a description of glenoid labral tears that exceed 180 degrees, and their characteristic magnetic resonance imaging features. In the young, heavily muscled male athlete, the identification of multiple sites of labral pathology and isolated, extensive posterior labral injuries are features that should raise suspicion for labral tears that exceed 180 degrees.

Objective: We describe 21 cases involving meniscal injury in which the meniscus appears free-floating on MRI of the knee. In these cases, the meniscus is completely surrounded by fluid. Correlation with surgical reports shows that the "floating" meniscus corresponds to a meniscal avulsion or detachment from the tibial plateau with an associated disruption of the meniscotibial coronary ligaments, which attach the meniscus to the tibia, allowing fluid to encompass the meniscus. A floating meniscus on MRI may represent a new specific finding for an uncommon form of meniscal injury known as meniscal avulsion., Conclusion: The presence of a floating meniscus on MRI is a result of significant trauma to the knee leading to meniscal avulsion and is often associated with significant ligamentous injury. Alerting the surgeon to the presence of a meniscal avulsion facilitates appropriate surgical planning with meniscal reattachment to the tibial plateau.

MRI has become increasingly helpful in establishing an early diagnosis of avascular necrosis(AVN). AVN often demonstrates a classic pattern on MRI; findings earlier in the course of the disease are less specific. Many pitfalls can complicate interpretation, and a number of pathologic conditions can share features of early AVN on MRI and plain radiographs. These entities should be distinguished from AVN, because treatment and prognosis may differ significantly.

Four patients with acromioclavicular joint injuries (one type II, two type III, one type V), two patients without acromioclavicular joint injury, and a fresh-frozen cadaver underwent magnetic resonance imaging (MRI) and plain radiographs. The normal conoid and trapezoid ligaments were easily identified in the cadaver and the two uninjured patients. Magnetic resonance imaging revealed disruption of both coraclavicular ligaments in the three patients with type II and type III injuries. However, the patient with the type V injury had disruption of the trapezoid ligament alone. Thus, the grade of injury, as determined by the change in the coracoclavicular interval onplain radiography and defined by the Rockwood classification system, failed to correlate with the pathoanatomy seen on MRI in two of the four injured patients. These findings suggest that improvements in the classification of these injuries may be necessary.

Background: Mesenchymal chondrosarcoma (MC) is an infrequent neoplasm, representing approximately 1% of all chondrosarcomas. Cytologic descriptions of MCs have been confined to rare case reports. In the current report, the authors describe their experience with the cytologic features of four MCs: two primary tumors and two metastatic lesions., Methods: Four patients were diagnosed with MC at the authors' institution from 1994 to 2002. Three of four patients underwent fine-needle aspiration (FNA) biopsy as part of their diagnosis; in the fourth patient, imprint cytology was performed. Each tumor also received histologic confirmation., Results: The patients studied included three females and one male. In three patients, the tumor presented initially as a soft tissue mass; whereas, in the remaining patient, the MC presented in the tibia. FNA results demonstrated small, oval-to-spindled cells with high nuclear-to-cytoplasmic ratios. Cells occurred singly and in clumps in a background of basophilic extracellular matrix. Histologic examination of each lesion demonstrated biphasic tumors, including focal areas of relatively mature cartilage formation as well as a small cell population., Conclusions: MC is a rare soft tissue tumor that occurs frequently in extraskeletal locations. FNA of these tumors can be diagnostic if the tumor is sampled appropriately and of critical features, such as the background extracellular matrix, are recognized. Given the propensity of these tumors to metastasize and the poor prognosis of patients with MC, early identification by FNA biopsy may allow earlier, more aggressive interventions., (Copyright 2003 American Cancer Society.)

Ankylosing spondylitis (AS) is one of a group of disorders characterized by association with HLA-B27 histocompatibility complex, seronegativity for rheumatoid factor, and propensity for inflammation at entheses, synovial articulations, and cartilaginous articulations. The radiographic hallmark of the disease is ankylosis, and the principle sites of involvement are the sacroiliac joints and spine, with less frequent involvement of other joints, including the pubic symphysis, hips, shoulders, knees, hands, feet, and sternoclavicular, acromioclavicular, sternomanubrial, and temporomandibular joints. Following a brief discussion of the basic pathophysiology and typical clinical findings of AS, we describe the typical magnetic resonance imaging features of the disease as it is manifests in the axial skeleton. Finally, a brief mention of special considerations in the radiographic evaluation of the AS patient in the setting of trauma is made.

Objective: Injury to the infrapatellar plica (ligamentum mucosum) has not been previously described in the radiology literature to our knowledge. This article shows the MR imaging appearance of injury to the infrapatellar plica., Conclusion: Injury to the infrapatellar plica is uncommon but should be considered as a potential source of knee pain, especially if no other evidence indicates internal derangement. MR imaging can reveal a typical appearance for infrapatellar plica injury.

Objective: Loose surgical tacks in the shoulder joint are a potential cause of new-onset shoulder pain after arthroscopic repair of an anterior-to-posterior lesion of the superior labrum. We report the MR imaging appearance of loose surgical tacks in this anatomic location., Conclusion: MR imaging is valuable in the evaluation of postoperative shoulder pain. Synovitis is a commonly considered clinical diagnosis; our report illustrates that loose tacks are another potential complication after shoulder surgery

Objective: A report in the orthopedics literature states that MR imaging for internal derangement of the knee has a lower accuracy in adolescents than in adults and may even provide spurious information that alters clinical management. This assertion has not been specifically addressed in the radiology literature. The purpose of our study was to determine the accuracy of MR imaging in adolescents with regard to injury of the cruciate ligaments and menisci., Materials and Methods: A database search of our institution's records from January 1998 to July 2000 yielded 2140 MR examinations of the knee, all of which had been performed with a standard knee protocol on a 1.5-T magnet. Of these 2140 examinations, 156 included patients younger than 18 years. Fifty-nine of these patients underwent surgery, and the orthopedic surgeons' operative reports were used as the gold standard with which the MR imaging results were compared. Thirty-four boys and 25 girls who ranged in age from 11 to 17 years (mean age, 15 years) were examined. The clinical notes for the remaining 97 patients were evaluated for information about management and clinical improvement., Results: The sensitivity and specificity values for MR imaging of the menisci and cruciate ligaments in adolescents were as follows: medial meniscus, 92% sensitivity and 87% specificity; lateral meniscus, 93% sensitivity and 95% specificity; anterior cruciate ligament, 100% sensitivity and 100% specificity; and posterior cruciate ligament, 0% sensitivity and 100% specificity., Conclusion: Our data suggest that MR imaging of the knee in adolescents is sensitive, specific, and accurate.

Objective: The purpose of our study was to evaluate the knees of asymptomatic high-level collegiate basketball players before the beginning of the basketball season to gain an understanding of nonclinical findings in this patient population., Subjects and Methods: Bilateral knee MR imaging examinations of 17 varsity basketball players (12 men and five women) were performed before basketball season began. All of the subjects were imaged on a 1.5-T magnet. The MR imaging studies were reviewed by two musculoskeletal radiologists. Structures analyzed were the menisci, ligaments, cartilage, plicae, and bone marrow. The presence of a joint effusion was also noted., Results: Fourteen (41%) of the 34 knees had bone marrow edema, eight (24%) showed signal in the patellar tendon, and 14 (41%) had abnormal cartilage signal or a focal abnormality. Twelve (35%) of the 34 knees showed a joint effusion. Two knees (6%) showed abnormal signal along the infrapatellar plica. Four knees (12%) were noted to have a discoid meniscus., Conclusion: An MR examination of the knees of high-level collegiate basketball players may show changes unique to this population. The changes seen on MR imaging in these athletes may be asymptomatic abnormalities. For instance, changes suggestive of patellar tendinopathy were identified in these asymptomatic subjects.

Background: The cytologic diagnosis of joint and articular surface-based lesions traditionally has been accomplished by examination of fluids or effusions. Although exfoliative cytology remains an accurate diagnostic test, not all joint-based lesions will produce effusions that are amenable to this type of examination. Fine-needle aspiration (FNA) represents an excellent alternative to traditional cytologic or histologic methods of diagnosis in joint pathology., Methods: The authors reviewed FNA materials for the period 1992-2001 from lesions of joint spaces and periarticular soft tissues. All diagnoses based on cytologic materials that were included in this study were confirmed with histologic follow-up. Cytologic and histologic materials were prepared using standard methods., Results: The authors found six relatively common lesions that were amenable to diagnosis by FNA. These included rheumatoid nodule, gouty tophi, ganglion cysts, pigmented villonodular synovitis, synovial chondromatosis, and synovial sarcoma. There are potential pitfalls in discriminating gout from pseudogout and synovial chondromatosis from chondrosarcoma., Conclusions: In most instances, mass-producing lesions of the joint space or the periarticular soft tissues can be diagnosed successfully by FNA. The common lesions are easily recognizable and are cytologically distinctive., (Copyright 2002 American Cancer Society.)

Objective: This study describes the MR imaging findings of focal osteochondral lesions found in the hips of 11 athletes with persistent pain and normal findings on radiographs., Conclusion: Osteochondral lesions of the femoral head are seen on MR imaging as focal, medial areas of high T2-weighted and low T1-weighted signals and should be considered as a possible cause of persistent hip or groin pain in young, high-level athletes because the institution of appropriate treatment may help to prevent late degenerative sequelae.

Objective: The purpose of this study was to evaluate whether a detectable abnormality was present on MR imaging without a visible fracture on conventional radiography in the setting of trauma. A recent retrospective study based on the presence or absence of periosteal reaction on follow-up radiographs concluded that fractures were not always present. The discrepancies in the literature over the usefulness of joint effusions as an indicator of fracture caused us to evaluate whether fractures were present more often than identified by conventional radiography. To do this, we used MR imaging., Materials and Methods: Thirteen consecutive patients (age range, 4-80 years; seven children and six adults), whose post-trauma elbow radiographs showed an effusion but no fracture, underwent screening MR imaging., Results: All patients showed bone marrow edema. Four of the seven children had fractures on screening MR imaging, and all adults had some identifiable fractures., Conclusion: Preliminary data using screening MR imaging suggests that an occult fracture usually is present in the setting of effusion without radiographically visualized fracture.

Objective: For suspected scaphoid fractures with no radiographic evidence of fracture, treating symptoms with immobilization and radiographic follow-up has long been the standard of care. Modified MR imaging of the wrist is offered at our institution in screening for radiographically occult scaphoid fractures at the time of initial presentation to the emergency department. We show the advantages and comparative costs of this modified protocol versus a traditional protocol., Materials and Methods: Our modified protocol consists of coronal thin-section T1-weighted and fast spin-echo T2-weighted MR images with fat saturation. A review of the literature was performed to assess the accuracy of clinical examination, radiography, and other modalities in the evaluation of scaphoid fractures of the wrist. Charges for this procedure are compared with charges for traditional follow-up., Results: Three of four patients with positive results at clinical examination and negative findings on initial radiographs will be needlessly immobilized and monitored. The charges to the patient at our institution for screening MR imaging of the wrist are $770. The total charges to the patient with the traditional protocol, which would not be necessary with screening MR imaging, are $677 or more if a diagnosis is not made at this time. Bone scanning or routine MR imaging is often eventually used., Conclusion: Cost analysis at our institution suggests the two protocols are nearly equivalent from a financial standpoint. The loss of productivity for patients who are unnecessarily in casts or splints may be substantial. Screening MR imaging of the wrist in this setting is becoming accepted at our institution in a manner similar to screening MR imaging of the hip.

Objective: We describe focal abnormal signal of the meniscus in the knees of six patients who had a history of acute trauma to the knee. This signal abuts the articular surface of the meniscus on MR imaging but does not meet criteria for a meniscal tear or degeneration., Conclusion: Acute trauma to the knee may cause an abnormal signal in the meniscus that does not meet the previously described criteria for a meniscal tear or an intrasubstance degeneration. This abnormal signal could be misinterpreted as a tear because of its contact with the articular surface; this signal is seen most often in our series in the setting of an anterior cruciate ligament tear with adjacent bone contusions. We suggest that this signal may be due to a contusion of the meniscus and that the signal may resolve over time in some patients.

Radiographs of the shoulders of 84 asymptomatic individuals aged between 40 and 83 years were evaluated to determine changes in 23 specific areas. Two fellowship-trained orthopaedic radiologists graded each area on a scale of 0 to II (normal 0, mild changes I, advanced changes II). Logistic regression analysis indicated age to be a significant predictor of change (p < 0.05) for sclerosis of the medial acromion and lateral clavicle, the presence of subchondral cysts in the acromion, formation of osteophytes at the inferior acromion and clavicle, and narrowing and degeneration of the acromioclavicular joint. Gender was not a significant predictor (p > 0.05) for radiological changes. Student's t-test determined significance (p < 0.05) between age and the presence of medial acromial and lateral clavicular sclerosis, subchondral acromial cysts, inferior acromial and clavicular osteophytes, and degeneration of the acromioclavicular joint. Radiological analysis in conditions such as subacromial impingement, pathology of the rotator cuff, and acromioclavicular degeneration should be interpreted in the context of the symptoms and normal age-related changes.

Objective: Patients with solitary plasmacytoma in the spine frequently require a biopsy for diagnosis of their condition. We report an appearance of plasmacytoma in the spine, which is sufficiently pathognomonic to obviate biopsy., Conclusion: Identification of a "mini brain" in an expansile lesion in the spine is characteristic of plasmacytoma. It is important that radiologists note this characteristic because biopsy can be avoided in patients with this appearance. Although biopsy might still be required at many institutions, at our institution, surgeons find this appearance sufficiently pathognomonic to bypass biopsy and start treatment.

Purpose: Longitudinal split tears of the peroneus brevis tendon have been increasingly reported as a source of lateral ankle pain and disability. MR imaging is useful in identifying the appearance of longitudinal split tears of the peroneus brevis tendon to differentiate this entity from other causes of chronic lateral ankle pain. We observed variations in anatomy associated with these tears., Materials and Methods: Twenty-two patients (eleven males, eleven females) were identified as having longitudinal split tears of the peroneus brevis tendon. These cases were reviewed retrospectively to evaluate for the following: shape of the peroneus brevis tendon, high signal in the peroneus brevis tendon, tendon subluxation, appearance of the superior peroneal retinaculum, presence of osseous changes in the ankle, lateral ankle ligaments, presence of a bony fibular spur, flattening of the peroneal groove of the fibula and presence of a peroneus quartus. A control group consisted of twenty ankles imaged for reasons other than lateral ankle pain. The same structures were assessed in this group. A Fisher's exact P-value was used to determine the significance of each finding in the two groups., Results: Statistically significant associated findings were chevron shaped tendon (p = .0001), high signal in the peroneus brevis (p = .0017), bony changes (p = .0001), flat peroneal groove (p = .0001), abnormal lateral ligaments (p = .0004), and lateral fibular spur (p = .0006)., Conclusions: MR imaging is useful in differentiating longitudinal split tears of the peroneus brevis tendon from other lateral ankle disorders. It can show the extent of the abnormality in the tendon and the associated findings of soft tissue and/or bone variations which must be addressed at the time of surgery.

Objective: Sacral stress fractures in athletes are rare but important to recognize because the symptoms often mimic sciatica and can lead to delay in diagnosis and treatment. The radiographic findings are characteristic and can facilitate early diagnosis and lead to appropriate treatment., Conclusion: The clinical presentation of runners with sacral stress fractures can mimic disk disease. However, stress fractures in athletes, especially long-distance runners, must be treated differently. The imaging characteristics appear as linear abnormal signal intensity paralleling the sacroiliac joint on MR imaging and linear sclerosis with cortical disruption on CT. Imaging with bone scintigraphy shows increased uptake that parallels the sacroiliac joint.

Macrodystrophia lipomatosa (MDL) is a rare disease typically causing localized gigantism and is often associated with a fibrolipomatous hamartoma (FH) of the median or plantar nerve. A previously unreported case of MDL with associated FH of the median nerve is presented.

Objective: As a therapeutic injection into the subacromial bursa (SAB) is commonly performed for impingement syndrome, it is important to know whether this fluid can be retained for a period of time and cause confusion with a pathologic collection of fluid. This study identifies and describes the appearance of recent subacromial injection using MR imaging, and the appearance of a potential complication., Design and Patients: Fourteen asymptomatic shoulders were studied with MR imaging using fast spin echo T2-weighted imaging (1.5 T) prior to injection with 7 cm(3) of xylocaine. Four shoulders had subacromial fluid and were eliminated from the study. The remaining 10 (9 men, 1 woman; age range 27-36 years, average age 33 years) were then re-imaged immediately, and at 6, 12 and 24 h after the injection or until fluid resolved. Each set of images was reviewed for the presence of fluid in the SAB and for additional abnormalities., Results: Fluid was identified in all subjects in the SAB in the immediate, 6 and 12 h post-injection images. At 24 h, fluid was not identified within the SAB in eight of 10 patients. In one patient fluid resolved in 48 h. The other continued to demonstrate fluid in the SAB and in the joint as well as abnormal signal in the infraspinatus muscle from a presumed myositis. Imaging was performed up to 10 days after the injection in this patient., Conclusions: It is known that fluid identified in the SAB without evidence of a cuff tear may be due to bursitis. However, if MR imaging is performed within 24 h of injection, the presence of the fluid may be iatrogenic. In addition, the history of recent therapeutic injection is very important as complications such as myositis can occur as a result of the injection. Knowledge of injection prior to imaging is vital for accurate interpretation of MR shoulder examinations.

Objective: Spondylolysis is reported in up to 7% of the population. An uncommon process that can accompany a pars interarticularis defect is a fibrocartilaginous mass, which can cause impression on the nerve roots and thecal sac. Recognition is important so that the presence may be addressed at the time of surgery. This report describes the MR imaging appearance and clinical significance of a fibrocartilaginous mass in association with spondylolysis., Materials and Methods: We reviewed data regarding 336 patients who had lumbar spine imaging at our institution during a 12-month period. Contiguous axial and sagittal MR imaging using T1-weighted and fast spin-echo T2-weighted sequences was used. Images were evaluated for a mass of tissue surrounding the pars defect with MR characteristics of cartilaginous and fibrous low signal intensity on T1-weighted images and low to intermediate signal intensity on T2-weighted images. The position of the fibrocartilaginous mass and its relation to the thecal sac were noted. Surgical correlation between those patients with a fibrocartilaginous mass and those without was examined., Results: Twenty-nine (8.6%) of 336 patients were identified as having a pars interarticularis defect. A fibrocartilaginous mass was present in 26 (90%) of 29 patients. Six (21%) of the 29 patients had a mass effect on the thecal sac. Of the remaining 23 patients, 20 had a fibrocartilaginous mass external to the thecal sac, and three did not show any fibrocartilaginous mass. Histologic analysis in one patient confirmed the fibrous and cartilaginous nature of the lesion at the pars defect., Conclusion: A fibrocartilaginous mass was present in 90% of the patients with spondylolysis. Mass effect on the thecal sac that required surgery was identified in 21% of the patients with spondylolysis. Awareness of this mass and proper imaging protocols will enable the radiologist to preoperatively alert the surgeon to its presence.

Objective: The subcoracoid bursa, a bursa anterior to the shoulder joint, can be identified on MR images. Awareness of the MR appearance and location of this bursa, which can connect with the subacromial-subdeltoid bursa, enables appropriate diagnosis in patients with shoulder pain., Materials and Methods: Dictated reports involving all MR imaging of the shoulder (n = 1545) performed at our institution from June 1993 to February 1998 were reviewed from computer archives. Films were reviewed in 16 cases describing a subcoracoid bursa; in nine MR imaging correctly revealed this bursa, whereas in seven MR imaging revealed the subscapular recess, an outpouching of the glenohumeral joint often confused with the subcoracoid bursa., Results: Of the 1545 shoulders examined, MR imaging revealed the subcoracoid bursa in nine (0.6%) patients. Two cases from a teaching file were also included, for a total of 11 cases. In five (45%) of the 11 cases, the subcoracoid bursa contained a small amount of fluid (<1 cm in largest diameter on sagittal images). In the remaining six cases (55%), the subcoracoid bursa contained a moderate (1-2 cm in largest diameter) or a large amount (>2 cm in largest diameter) of fluid. Of the 11 cases, six (55%) also showed connection with the subacromial-subdeltoid bursa., Conclusion: It is important to correctly identify the subcoracoid bursa on MR imaging because it is believed to cause isolated shoulder pain. Fluid in the subcoracoid bursa can also communicate with the subacromial-subdeltoid bursa.

Objective: To demonstrate with radiographic imaging the association between pubic stress injury and sacroiliac abnormalities in athletes., Design and Patients: Eleven athletes (9 men and 2 women), comprising seven male long-distance runners, one male soccer player, one male and two female basketball players, were imaged with plain films for complaints of pubic symphysis pain, sciatica, groin pain, or a combination of these complaints. In addition to the plain films, four patients were imaged with CT, two patients had MR imaging, and a bone scan was performed in three patients. Anteroposterior plain films of the pelvis of 20 patients without back pain or pubic pain were evaluated for comparison as a control group (ages 18-72 years, average 49 years; 11 women and 9 men)., Results: All athletes showed plain film evidence of either sclerosis, erosions or offset at the pubic symphysis. Four had avulsion of cortical bone at the site of insertion of the gracilis tendon. Four patients demonstrated sacroiliac joint abnormalities on plain films consisting of sclerosis, erosions and osteophytes, and in one of these athletes, bilateral sacroiliac changes are present. Two patients with normal sacroiliac joints on plain films had a bone scan showing increased radionuclide uptake bilaterally at the sacroiliac joints. One patient with both plain film and CT evidence of sacroiliac abnormalities had an MR examination showing abnormal signal at both sacroiliac joints and at the pubic symphysis. A sacral stress fracture was found on CT in one patient with complaints of sciatica. In the control group, six patients, all over the age of 55 years, had mild sclerosis of the symphysis, but no plain film evidence of sacroiliac abnormalities., Conclusion: We have found a group of athletes in whom stress injuries to the pubic symphysis are associated with changes in the sacroiliac joint as demonstrated by degenerative changes or in the sacrum as manifested as a sacral stress fracture. These findings are probably due to abnormal stresses across the pelvic ring structure that lead to a second abnormality in the pelvic ring. The abnormality in the sacrum is not always well seen with conventional imaging. Recognition of the association of stress injury of the symphysis with back pain is important in that it can help avoid inappropriate studies and diagnostic confusion.

Musculoskeletal manifestations in the HIV- and AIDS-infected patient are not as common as in other organ systems. A variety of musculoskeletal abnormalities are discussed in this article, including infection, arthritis, and neoplasms. A brief discussion of miscellaneous conditions, such as avascular necrosis, hypertrophic osteoarthropathy, reflex sympathetic dystrophy, and bone marrows abnormalities is also included.

Objective: To show that absence or interruption of the supra-acetabular line is a subtle plain film indicator of pathology in the acetabulum., Design: Nineteen hips from 17 patients with known disease processes involving the acetabulum as demonstrated by subsequent magnetic resonance imaging, bone scan or plain film follow-up were evaluated with antero-posterior (AP) plain films of the pelvis. Three additional cases were diagnosed prospectively using interruption of the supra-acetabular line as the criterion for inclusion. Fifty AP plain films of the pelvis in patients without hip pain were examined prospectively to determine normal imaging criteria., Results and Conclusions: The normal supra-acetabular line measures 2-3 mm in thickness superiorly and is a thin sclerotic line in the medial aspect. In all 22 hips (with pathology) in this series, the line was interrupted or absent. Loss or interruption of the supra-acetabular line may thus be a subtle pain film indicator of a disease process involving the acetabulum. This plain film sign has not previously been reported.