Detection of cartilage damage in femoroacetabular impingement with standardized dGEMRIC at 3 T.

OBJECTIVE: This study aimed at identifying the optimal threshold value to detect cartilage lesions with Standardized delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) at 3 T and evaluate intra- and inter-observer repeatability. DESIGN: We retrospectively reviewed 20 hips in 20 patients. dGEMRIC maps were acquired at 3 T along radial imaging planes of the hip and standardized to remove the effects of patient's age, sex and diffusion of gadolinium contrast. Two observers separately evaluated 84 Standardized dGEMRIC maps, both by visual inspection and using an average index for a region of interest (ROI) in the acetabular cartilage. A radiologist evaluated the acetabular cartilage on morphologic MR images at exactly the same locations. Using intra-operative findings as reference, the optimal threshold to detect cartilage lesions with Standardized dGEMRIC was assessed and results were compared with the diagnostic performance of morphologic magnetic resonance imaging (MRI). RESULTS: Using z < -2 as threshold and visual inspection of the color-adjusted maps, sensitivity, specificity and accuracy for Observer 1 and Observer 2, were 83%, 60% and 75%, and 69%, 70% and 69%, respectively. Overall performance was 52%, 67% and 58%, when using an average z for the acetabular cartilage, compared to 37%, 90% and 56% for morphologic assessment. The kappa coefficient was 0.76 and 0.68 for intra- and inter-observer repeatability, respectively, indicating substantial agreement. CONCLUSIONS: Standardized dGEMRIC at 3 T is accurate in detecting cartilage damage and could improve preoperative assessment in femoroacetabular impingement (FAI). As cartilage lesions in FAI are localized, visual inspection of the Standardized dGEMRIC maps is more accurate than an average z for the acetabular cartilage.

Micro-finite element analysis applied to high-resolution MRI reveals improved bone mechanical competence in the distal femur of female pre-professional dancers.

UNLABELLED: Micro-finite element analysis applied to high-resolution (0.234-mm length scale) MRI reveals greater whole and cancellous bone stiffness, but not greater cortical bone stiffness, in the distal femur of female dancers compared to controls. Greater whole bone stiffness appears to be mediated by cancellous, rather than cortical bone adaptation. INTRODUCTION: The purpose of this study was to compare bone mechanical competence (stiffness) in the distal femur of female dancers compared to healthy, relatively inactive female controls. METHODS: This study had institutional review board approval. We recruited nine female modern dancers (25.7±5.8 years, 1.63±0.06 m, 57.1±4.6 kg) and ten relatively inactive, healthy female controls matched for age, height, and weight (32.1±4.8 years, 1.6±0.04 m, 55.8±5.9 kg). We scanned the distal femur using a 7-T MRI scanner and a three-dimensional fast low-angle shot sequence (TR/TE=31 ms/5.1 ms, 0.234 mm×0.234 mm×1 mm, 80 slices). We applied micro-finite element analysis to 10-mm-thick volumes of interest at the distal femoral diaphysis, metaphysis, and epiphysis to compute stiffness and cross-sectional area of whole, cortical, and cancellous bone, as well as cortical thickness. We applied two-tailed t-tests and ANCOVA to compare groups. RESULTS: Dancers demonstrated greater whole and cancellous bone stiffness and cross-sectional area at all locations (p<0.05). Cortical bone stiffness, cross-sectional area, and thickness did not differ between groups (>0.08). At all locations, the percent of intact whole bone stiffness for cortical bone alone was lower in dancers (p<0.05). Adjustment for cancellous bone cross-sectional area eliminated significant differences in whole bone stiffness between groups (p>0.07), but adjustment for cortical bone cross-sectional area did not (p<0.03). CONCLUSIONS: Modern dancers have greater whole and cancellous bone stiffness in the distal femur compared to controls. Elevated whole bone stiffness in dancers may be mediated via cancellous, rather than cortical bone adaptation.

MR imaging of the knee ligaments and the postoperative knee.

MR imaging is an accurate, noninvasive, and cost-effective method for the evaluation of acute knee ligament injuries and in the examination of the postoperative knee. Understanding the normal anatomy and the pertinent clinical aspects of knee injuries is a prerequisite for accurate interpretation of MR imaging studies. The increasing popularity of ACL reconstruction following disruption of this ligament requires knowledge of the various surgical techniques and their MR imaging appearance as well as the appearance of possible complications.

Magnetic resonance imaging of articular cartilage: an overview.

MR imaging is the best noninvasive method for the evaluation of articular cartilage. Recent studies have clarified the MR appearance of normal articular cartilage and proven that MR imaging can detect chondral lesions with high accuracy. Quantitative imaging holds promise for the accurate determination of cartilage volumes and thickness measurements, as well as the ability to detect early chondral degeneration and biochemical changes before gross morphologic changes occur.

Outcomes of postoperative septic arthritis after anterior cruciate ligament reconstruction.

Arthroscopically guided reconstruction of the anterior cruciate ligament is a common orthopaedic procedure. While many associated complications have been described in the literature, postoperative septic arthritis has received little attention. Although rare after anterior cruciate ligament reconstruction, septic arthritis can have devastating consequences. From a group of 831 consecutive patients, we report 4 (0.48%) who sustained septic arthritis. All patients had similar symptoms and were treated by the same surgeon in the same manner. All underwent immediate arthroscopic lavage, open incision, drainage of associated wounds, debridement with graft retention, and treatment with intravenous and then oral antibiotics. The patients underwent an average of 2.75 procedures after the diagnosis to eradicate the infection and restore knee motion. All patients were evaluated at an average of 3 years after surgery. We found that previous knee surgery and meniscal repair were risk factors for the development of postoperative septic arthritis. The infection was successfully eradicated, the ligament graft was preserved, and knee stability and mobility were adequately restored in all patients. However, the clinical outcome of these patients appeared to be inferior to that of patients who had undergone uncomplicated anterior cruciate ligament reconstruction. This inferior outcome appeared to be secondary to damage to the articular cartilage from the infection.

Second time around: evaluating the postoperative anterior cruciate ligament.

Anterior cruciate ligament (ACL) injuries are especially common in the younger athletic population. In 1998, more than 100,000 ACL reconstructions were performed. MR imaging examination has proved to be valuable in imaging and evaluating ACL reconstructions. This article reviews different surgical reconstruction procedures, indications for postoperative MR imaging, and the MR imaging appearance seen in routine ACL reconstructions and in complications associated with ACL reconstructions.

Magnetic resonance imaging of the foot and ankle.

Magnetic resonance (MR) imaging of the foot and ankle is playing an increasingly important role in the diagnosis of a wide range of foot and ankle abnormalities, as well as in planning for their surgical treatment. For an optimal MR study of the foot and ankle, it is necessary to obtain high-resolution, small-field-of-view images using a variety of pulse sequences. The most common indication for MR imaging of the foot and ankle is for the evaluation of tendon and bone abnormalities, such as osteomyelitis, occult fractures, and partial and complete tears of the Achilles, tibialis posterior, and peroneal tendons. Magnetic resonance imaging has also been shown to be helpful in the diagnosis of several soft-tissue abnormalities that are unique to the foot and ankle, such as plantar fasciitis, plantar fibromatosis, interdigital neuromas, and tarsal tunnel syndrome.

Radiology of wrist and hand injuries in athletes.

Traumatic injuries are a major cause of hand and wrist pain in athletes. Wrist injuries include fractures, dislocations, and instability patterns. Hand injuries include tendon injuries, ligamentous injuries, and fractures. In this article we have presented the radiographic appearance of the more common of these injuries.

Imaging modalities for study of the distal ulnar region.

Judicious use of diagnostic imaging maximizes the diagnostic capabilities of the surgeon treating the distal radio-ulnar joint (DRUJ). A good clinical history and clinical examination are necessary to direct the selection of appropriate imaging studies. Plain radiographs are almost always the first imaging examination. More advanced imaging techniques are costly and may provide only limited information. This article discusses imaging modalities useful for assessment of the DRUJ and the area around it.

Magnetic resonance imaging of articular cartilage: the state of the art.

Recent advances in the treatment of articular cartilage abnormalities have created a need for an accurate noninvasive imaging method for the evaluation of articular cartilage. Although its role remains undefined in this regard, magnetic resonance imaging (MRI) appears to be the most promising method. We review the current status and possible future directions of MRI of articular cartilage.

Glenoid labrum ossification and mechanical restriction of joint motion: extraosseous manifestations of melorheostosis.

We report a case of a 47-year-old man who presented with progressive loss of motion and pain in the right shoulder. Radiographs of the shoulder demonstrated dense ossification in the glenoid and humeral head with extension into the periarticular soft tissues. CT and MRI scans confirmed the radiographic findings and also revealed ossification of the glenoid labrum. A radiographic diagnosis of melorheostosis, an uncommon benign sclerosing bone dysplasia, was made. Because of the patient's severe symptomatology, he underwent total shoulder arthroplasty. Histological analysis of the resected masses was consistent with melorheostosis with a few areas covered by a cartilage cap. This case illustrates several uncommon but important features of melorheostosis, including mechanical obstruction of joint motion requiring joint replacement, ossification of the glenoid labrum, and cartilage-covering portions of the intra-articular masses, not to be confused with cartilage-producing tumors.

MR imaging of articular cartilage: current status and future directions.

Advances in surgical and pharmacologic techniques for treating and preventing chondral abnormalities are creating a demand for an accurate, noninvasive imaging method to evaluate articular cartilage. The most promising technique is MR imaging, but its exact role in this evaluation remains undefined. This article reviews the MR appearance of normal and abnormal articular cartilage and the various pulse sequences that can be used to evaluate chondral lesions. It also briefly discusses possible future directions for MR imaging of articular cartilage.

Clinical imaging of articular cartilage in the knee.

Assessment of articular cartilage has become an essential part of magnetic resonance (MR) evaluation of the knee. This has occurred because of recent advances in treatment along with improved accuracy of MR image evaluation of articular cartilage. Detection of articular cartilage defects can provide an explanation for symptoms and allow identification of patients for cartilage therapy and is an important factor for predicting prognosis of patients with knee injury. This review describes the most easily implemented MR techniques for evaluation of articular cartilage and the normal and abnormal appearance of cartilage seen using these techniques. The influence of imaging findings on treatment is described.

MR imaging of articular cartilage.

With the advent of new treatments for articular cartilage disorders, accurate noninvasive assessment of articular cartilage, particularly with MR imaging, has become important. Understanding the MR imaging features of articular cartilage has led to the development of two types of routinely available MR imaging techniques which have demonstrated clinical accuracy and interobserver reliability.

Adamantinoma.

This is an unusual case of an adamantinoma in an early phase of evolution. It was much smaller than adamantinomas typically seen at presentation, although it was located in the usual anterior tibial cortical region. Slow growth and a prolonged period of symptoms are common with adamantinoma and were also observed in this patient. The multifocal presentation within the same bone is unusual. This case illustrated the need to consider adamantinoma in the differential diagnosis of any pre-tibial cortical lesion despite the small size, benign presentation, or the longevity of symptoms.

Vascular anomalies in association with osteodystrophies--a spectrum.

A wide spectrum of osseous abnormalities has been reported in association with vascular lesions. Enchondromas, bone hypertrophy, bone lysis, and sclerotic bone lesions have all been reported in association with hemangiomas, lymphangiomas, varicosities, and arteriovenous fistulae. These associations can be grouped into four major syndromes: Maffucci syndrome, mixed sclerosing bone dystrophy with angiodysplasia, congenital angiectatic hypertrophy (Klippel-Trenaunay-Weber syndrome), and massive osteolysis (Gorham syndrome).

Fat suppressed MRI of articular cartilage with a spatial-spectral excitation pulse.

We developed a three-dimensional, gradient-recalled-echo imaging technique that incorporates a short-duration spatial-spectral excitation pulse from the family of binomial pulses. Binomial pulses of different orders were tested on phantoms and on normal volunteers to find the composite pulse that produced in the shortest duration the most reliable fat suppression. Composite pulses employing unipolar slice-selective gradients with explicit rewinder gradients between each radio-frequency (RF) pulse were compared with composite RF pulses employing alternating-polarity, slice-select gradients. The advantage of the sequences using the unipolar gradients is improved fat suppression. Images of the knees of volunteers produced with the composite RF pulse have contrast between fat and articular cartilage equivalent to that on images created by the gradient-recalled-echo imaging technique employing a conventional chemsat pulse. The optimum RF pulse consisted of three amplitude- and phase-modulated pulses combined with unipolar slice-select gradients.