MRI following primary repair of the anterior cruciate ligament.

Primary repair of the anterior cruciate ligament (ACL) is being performed increasingly in the treatment of acute proximal ACL ruptures. Advantages of ACL repair over surgical reconstruction with a tendon graft include preservation of the anatomy and proprioceptive function of the native ACL, and therefore, faster rehabilitation. The addition of an internal brace protects the repair during ACL healing and can increase the success rate of the procedure. Given this evolution of ACL surgical treatment, radiologists should be familiar with the new repair techniques and their appearances on postoperative imaging. In this article, we describe two different surgical techniques for primary ACL repair, dynamic intraligamentary stabilisation and internal brace ligament augmentation, and provide an overview of the normal and abnormal appearances after this type of repair at magnetic resonance imaging (MRI) follow-up.

Grading and characterization of soft tissue tumors on magnetic resonance imaging: the value of an expert second opinion report.

OBJECTIVE: To retrospectively compare the accuracy of the initial MRI (magnetic resonance imaging) report of referring radiologists and the second opinion report. MATERIAL AND METHODS: MRI of 155 patients presenting with a soft tissue tumor (STT) in a single large community center were referred for inclusion in the Belgian Soft Tissue Neoplasm Registry (BSTNR). The initial report and the second opinion report were made independently. Histopathology (gold standard) was obtained in 90 patients (group 1). In 65 patients, the diagnosis was made by the combination of clinical findings and/or follow-up (group 2). In group 1, the concordance in grading and tissue-specific (TS) diagnosis between the referring center (RC) and expert center (EC) was reviewed. RESULTS: In group 1, MR grading yields a sensitivity of 100% and a specificity of 89% in the EC. The sensitivity was 88% and the specificity 81% in the RC. The accuracy was significantly higher in the EC (92%) compared to the RC (83%) (p = 0.039). The TS diagnosis was correct in 50% versus 38.5% of malignant tumors and in 71.8% versus 51.6% of benign tumors in the EC and RC respectively. CONCLUSION: A second opinion report increases the accuracy in the diagnosis of STT on MRI. MAIN MESSAGES: • A second opinion MRI report increases the overall accuracy in the diagnosis of soft tissue tumors. • There is a good overall agreement in MR grading between the referring and expert institution. • In the expert center, there were fewer false-negative and false-positive diagnoses. • MRI performs better in the tissue-specific diagnosis of benign versus malignant STT.

Tears of the supraspinatus tendon: assessment with indirect magnetic resonance arthrography in 67 patients with arthroscopic correlation.

BACKGROUND: Magnetic resonance (MR) arthrography is generally regarded as the gold standard for shoulder imaging. As an alternative to direct MR arthrography, the less invasive indirect MR arthrography technique was proposed, offering logistic advantages because fluoroscopic or ultrasonographic guidance for joint injection is not required. PURPOSE: To assess the diagnostic performance of indirect MR arthrography in the diagnosis of full- and partial-thickness supraspinatus tears in a symptomatic population. MATERIAL AND METHODS: Two radiologists with different levels of experience independently and retrospectively interpreted indirect MR (1.5T) arthrograms of the shoulder obtained in 67 symptomatic patients who underwent subsequent arthroscopy. On MR, the supraspinatus tendon was evaluated for full- or partial-thickness tear. With arthroscopy as the standard of reference, sensitivity, specificity, and diagnostic accuracy of indirect MR arthrography in the detection of full- and partial-thickness tears of the supraspinatus tendon was calculated. Kappa (kappa) statistics were used for the assessment of the agreement between arthroscopic and imaging findings and for the assessment of interobserver agreement. RESULTS: For full-thickness tears of the supraspinatus tendon, sensitivities, specificities, and accuracies exceeded 90% for both observers, with excellent interobserver agreement (kappa = 0.910). For partial-thickness tears, sensitivities (38-50%) and accuracies (76-78%) were poor for both reviewers, and interobserver agreement was moderate (kappa = 0.491). Discrepancies between MR diagnosis and arthroscopy were predominantly observed with small partial-thickness tears. CONCLUSION: Indirect MR arthrography is highly accurate in the diagnosis of full-thickness rotator cuff tears. However, the diagnosis of partial-thickness tears with indirect MR arthrography remains faulty, because exact demarcation of degenerative change and partial rupture is difficult. On the basis of the above findings, we do not recommend indirect MR arthrography on patients for whom rotator cuff disease is suspected clinically.

Imaging of femoroacetabular impingement: pictorial review.

Femoroacetabular impingement (FAI) is a cause of progressive osteoarthritis of the hip in younger patients. Three types of FAI have been described: a cam-type, a pincer-type and a mixed type. Early recognition of the morphologic hip features of each type of impingement is important, because arthroscopic treatment is still successful in the initial stage to prevent or delay further hip degeneration. This article reviews the imaging features of the different types of FAI. Magnetic resonance arthrography (MRA) is the preferred modality to detect, localise and characterise the type of FAI and the resulting injuries of the acetabular hyaline cartilage and fibrocartilaginous labrum.

Magnetic resonance imaging of variants of the knee.

Magnetic resonance imaging has become the imaging modality of choice for evaluation of internal derangements of the knee. Anatomical variants are often an incidental finding on these examinations. Knowledge and recognition of variants is important, not only to avoid misdiagnosis but also to avoid additional imaging and over-treatment. This pictorial essay provides an overview of variants encountered during a review of 1,873 magnetic resonance imaging examinations of the knee. Emphasis is laid on these variants that are clinically important.

Ewing's sarcoma: imaging features.

AIM: To define an imaging prototype of Ewing's sarcoma (ES). MATERIALS AND METHODS: Sixty-four patients with a histopathologically and/or genetically proven diagnosis of ES were analyzed for clinical parameters (age, gender and location), radiographic and CT appearance (distribution, matrix, margins, periosteal reaction, articular extension, cortical reaction and the presence of a pathologic fracture). Size, local extension, signal intensity, degree and pattern of enhancement, and the presence of skip metastases were evaluated on MRI. Distant metastases were recorded on bone scintigraphy and chest CT scan. RESULTS: Patient's age ranged between 7-67 (mean 17.9). Male/female ratio was 2.4/1. Location in the pelvis was most frequent (31%), followed by the femur (20%) and tibia (11%). Most tumors were mixed lytic-sclerotic (75%), and purely lytic in 25%. Plain films and CT scan showed a spiculated periosteal reaction in 50%. A Codman's triangle was seen in 27%. Articular extension was difficult to assess on radiographs. Cortical permeation and destruction is seen in respectively 31 and 42%, whereas cortical thickening is seen in 20%. Pathologic fracture occurred in 7.8%. MRI showed a large mass, with a soft tissue component of more than 50% in 67%. Degree and pattern of enhancement pattern was variable. Signal intensity on T1- and T2-WI was non-specific. Joint involvement was seen in 23%. Isolated involvement of the soft tissue (extraskeletal ES) was seen in 1.5%. Skip metastases at initial presentation were present at initial presentation in 14% and distant metastases in 22%. CONCLUSIONS: ES occurs in young patients. On radiographs/CT, 37.5% are located in the axial skeleton and 62.5% in the peripheral skeleton. ES is mostly mixed sclerotic-lytic. A spiculated periosteal reaction is most frequent. The most characteristic finding on MRI is the presence of a large soft tissue mass.

Proceedings of the European Society of Musculoskeletal Radiology (ESSR) training module, Antwerp, 20-21.01.05. Part two: bone tumors. Benign bone lesions: characteristic imaging features.

Benign bone lesions are a fairly common finding in radiology practice. Often, the combination of patient's age and plain radiographic findings are sufficient for diagnosis and obviates the need for further imaging. Generally the following parameters should be assessed in the evaluation of a bone lesion: clinical features, age of the patient, location, size, pattern of bone destruction, cortical involvement, zone of transition, sclerotic margination and matrix calcification. Cross sectional imaging, such as CT or MRI complements radiography, especially in complex anatomical sites. This article reviews the spectrum of clinical and imaging appearances of the most common benign bone tumors.

Imaging of malignant bonetumors.

Diagnostic imaging plays a pivotal role in the initial detection, characterization, pre-operative assessment and long term follow-up of malignant bone tumors. The purpose of this brief review is to discuss the specific role of the different imaging modalities in the diagnostic work-up of malignant bone tumors. The imaging features, with emphasis on standard radiography, allowing differentiation, of malignant bone tumors, will be highlighted.

Imaging of soft tissue tumors: general imaging strategy and technical considerations.

This paper reviews the imaging strategy and protocol for detection, grading and staging, and posttherapeutic follow-up of soft tissue tumors (STT), used in our institution. The role of each imaging technique, with emphasis on magnetic resonance imaging, is highlighted.

Imaging of vascular soft tissue tumors.

Most tumors of the vascular system are benign, cutaneous or subcutaneous lesions that are usually readily diagnosed without significant differential diagnosis. On the other hand, lesions that arise in deep soft tissues have to be differentiated from malignant neoplasms. In these cases, further imaging work-up is necessary for local staging and planning therapy. Vascular lesions of intermediate malignancy and malignant vascular tumors are very rare and demonstrate nonspecific imaging findings. This manuscript aims to give a brief overview of vascular soft-tissue tumors and to discuss the imaging appearances.

Imaging of joint tumors.

The paper gives an overview of the present nosological classification and imaging features of synovial tumors and tumor-like conditions of joints. The merits of each imaging technique will be emphasized.

Helical CT and dynamic Mr features of an adrenal ganglioneuroma.

We report a case of a young female patient with an adrenalganglioneuroma and describe the helical CT and dynamic MRI features that can be suggestive for the diagnosis.

Prevalence, extension and characteristics of fluid-fluid levels in bone and soft tissue tumors.

The purpose of this study was to determine the prevalence, extension and signal characteristics of fluid-fluid levels in a large series of 700 bone and 700 soft tissue tumors. Out of a multi-institutional database, MRI of 700 consecutive patients with a bone tumor and MRI of 700 consecutive patients with a soft tissue neoplasm were retrospectively reviewed for the presence of fluid-fluid levels. Extension (single, multiple and proportion of the lesion occupied by fluid-fluid levels) and signal characteristics on magnetic resonance imaging of fluid-fluid levels were determined. In all patients, pathologic correlation was available. Of 700 patients with a bone tumor, 19 (10 male and 9 female; mean age, 29 years) presented with a fluid-fluid level (prevalence 2.7%). Multiple fluid-fluid levels occupying at least one half of the total volume of the lesion were found in the majority of patients. Diagnoses included aneurysmal bone cyst (ten cases), fibrous dysplasia (two cases), osteoblastoma (one case), simple bone cyst (one case), telangiectatic osteosarcoma (one case), "brown tumor" (one case), chondroblastoma (one case) and giant cell tumor (two cases). Of 700 patients with a soft tissue tumor, 20 (9 males and 11 females; mean age, 34 years) presented with a fluid-fluid level (prevalence 2.9%). Multiple fluid-fluid levels occupying at least one half of the total volume of the lesion were found in the majority of patients. Diagnoses included cavernous hemangioma (12 cases), synovial sarcoma (3 cases), angiosarcoma (1 case), aneurysmal bone cyst of soft tissue (1 case), myxofibrosarcoma (1 case) and high-grade sarcoma "not otherwise specified" (2 cases). In our series, the largest reported in the literature to the best of our knowledge, the presence of fluid-fluid levels is a rare finding with a prevalence of 2.7 and 2.9% in bone and soft tissue tumors, respectively. Fluid-fluid levels remain a non-specific finding and can occur in a wide range of bone and soft tissue tumors, both benign and malignant. Therefore, they cannot be considered diagnostic of any particular type of tumor, and the diagnosis should be made on the basis of other radiological and clinical findings.

Ankylosing spondylitis: what remains of the standard radiography anno 2004?

In this review, the radiographic features of ankylosing spondylitis of the axial skeleton will be discussed shortly. Three pathologic processes, including inflammation, bony repair and ossification occurring consecutively or simultaneously, will contribute to the radiographic picture of ankylosing spondylitis. Typical target sites at which these processes take place are the synovial joints, discovertebral joints and ligamentous attachments or entheses of the axial skeleton.

Imaging of tumours of the foot and ankle.

The general presentation of osseous and soft-tissue neoplasms of the foot and ankle is not different from lesions encountered in other parts of the body and imaging features may be nonspecific. Some lesions, however, have a predilection for the foot and ankle and may have typical imaging features, such as plantar fibromatosis or intraosseous lipoma. This presentation aims to give an overview of bone and soft-tissue tumours of the foot and ankle and to discuss the strength of each imaging modality in the diagnosis.