RESUMEN
OBJECTIVE: The purpose of this study was to evaluate the accuracy of the fast spin-echo technique in detecting meniscal tears of the knee using a 3-T MRI system. CONCLUSION: We concluded from this study that 3-T MRI using fast spin-echo sequences is highly accurate in the detection of medial and lateral meniscal tears of the knee.
Asunto(s)
Traumatismos de la Rodilla/diagnóstico , Imagen por Resonancia Magnética , Lesiones de Menisco Tibial , Adolescente , Adulto , Anciano , Artroscopía , Femenino , Humanos , Traumatismos de la Rodilla/cirugía , Imagen por Resonancia Magnética/métodos , Masculino , Meniscos Tibiales/cirugía , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Sensibilidad y EspecificidadRESUMEN
As 3T MR imaging systems become more wide-spread in the clinical realm, a full understanding of the opportunities for image improvement and the limitations in the applications of the signal gain is needed. It is clear that even with current coil technology, much of the gain in signal can be harnessed effectively; however, continued coil development is necessary to realize the full potential of 3T, especially with the wonderful synergy that can be achieved with the use of parallel imaging and multiple-channel phased-array extremity coils. Furthermore, despite the theoretic imaging challenges at higher field strengths (eg, susceptibility, chemical shift, SAR, pulsation, T1 time prolongation, and T2 time shortening), the techniques and methods that were discussed above can eliminate any obstacles to clinical imaging. This creates excellent opportunities to improve image quality, spatial resolution, and diagnostic accuracy in the musculo-skeletal system. From the author's experience, the superb image quality has impressed referring orthopedic surgeons, and the reduction in scan time has resulted in greater patient satisfaction and reduced anxiety.
Asunto(s)
Aumento de la Imagen/instrumentación , Imagen por Resonancia Magnética/instrumentación , Enfermedades Musculoesqueléticas/diagnóstico , Artefactos , Humanos , Aumento de la Imagen/métodos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética/métodosRESUMEN
The gain in SNR that is afforded by 3T MR imaging systems has tremendous clinical applications in the musculoskeletal system. The potential for demonstrating and enhancing the visibility of normal osseous, tendinous, cartilaginous, and ligamentous structures is exciting. Furthermore, harnessing this added signal to increase spatial resolution may improve our diagnostic abilities in various joints dramatically. Radiologists have enjoyed great success in assessing joint disease with current MR imaging field strengths; however, many intrinsic joint structures remain poorly evaluated, which leads to a golden opportunity for 3T MR imaging. The articular cartilage of the knee, the glenoid labrum of the shoulder, the intrinsic ligaments and TFC of the wrist, the collateral ligaments of the elbow, the labrum and articular cartilage of the hip, and the collateral ligaments of the ankle have been evaluated suboptimally on 1 .5T systems using routine nonarthrographic MR images. Because of the enhanced SNR, the higher spatial resolution, and the greater CNR of intrinsic joint structures at higher field strengths, 3T MR imaging has the potential to improve diagnostic abilities in the musculoskeletal system vastly, which translates into better patient care and management. The author's 2 years of clinical experience with musculoskeletal MR imaging on 3T systems has met and exceeded his expectations, and has bolstered the confidence of his orthopedic surgeons in his diagnoses. As coil technology advances and as the use of parallel imaging becomes more available in the extremities, the author expects to see even more dramatic improvements in image quality.
Asunto(s)
Imagen por Resonancia Magnética/métodos , Enfermedades Musculoesqueléticas/diagnóstico , Humanos , Aumento de la Imagen/instrumentación , Aumento de la Imagen/métodos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética/instrumentaciónRESUMEN
OBJECTIVE: To investigate the MR characteristics of SONK-like (spontaneous osteonecrosis of the knee) subchondral abnormalities in the adult atraumatic knee and to recategorize these patients into two subgroups: a subacute to chronic process associated with osteoarthritis and an acute process associated with insufficiency fractures. DESIGN: We retrospectively examined the knee MRIs of 39 patients with non-specific interpretations of osteochondral abnormalities. PATIENTS: There were a total of 52 subchondral lesions without any known traumatic event and no prior surgery. All lesions evaluated had MR features previously ascribed to SONK. Several MR characteristics were then assessed: presence or absence of a line, size, zonal location, T1 and T2 signal, associated marrow edema, associated ipsilateral meniscal tear, and associated ipsilateral cartilage defects. RESULTS AND CONCLUSIONS: The abnormalities with linear components (insufficiency fractures) tended to be larger (P<0.01) and were associated with a severe amount of marrow edema (P<0.0001) consistent with an acute process. The non-linear abnormalities were more associated with cartilage defects (P=0.01) and less marrow edema consistent with osteoarthritis and a subacute to chronic process. This association of SONK-like abnormalities with osteoarthritis and insufficiency fractures casts doubt on the validity of the term "spontaneous osteonecrosis" as it is currently applied, and further investigation into the separate etiologies of these subchondral marrow lesions is needed.
Asunto(s)
Articulación de la Rodilla/patología , Imagen por Resonancia Magnética , Osteonecrosis/patología , Enfermedad Aguda , Adulto , Anciano , Enfermedades de la Médula Ósea/patología , Enfermedades de los Cartílagos/patología , Enfermedad Crónica , Edema/patología , Femenino , Fracturas Espontáneas/patología , Humanos , Traumatismos de la Rodilla/patología , Masculino , Meniscos Tibiales/patología , Persona de Mediana Edad , Osteoartritis de la Rodilla/patología , Estudios Retrospectivos , Rotura EspontáneaRESUMEN
OBJECTIVE: The simultaneous acquisition of spatial harmonics (SMASH) technique is a parallel imaging technique that uses fewer echoes than conventional techniques to obtain the desired resolution. Production of images occurs more quickly with parallel imaging than with conventional imaging. This study assesses the usefulness of the SMASH technique for MRI of the shoulder. SUBJECTS AND METHODS. Five experienced musculoskeletal radiologists prospectively interpreted MRIs of the shoulder in 50 consecutive patients. All patients underwent a complete MRI examination of the shoulder on a 1.5-T commercially available scanner. Axial fat-saturated proton density-weighted, coronal T1-weighted, and coronal and sagittal fat-saturated T2-weighted sequences were performed. Patients also underwent SMASH T2-weighted imaging in the coronal and sagittal planes. Coronal and sagittal SMASH T2-weighted imaging took approximately 50% as long to complete compared with conventional T2-weighted imaging. Each radiologist interpreted MRIs of the shoulder without knowing whether the images were obtained using the SMASH or the fat-saturated T2-weighted technique. Twenty-eight of the 50 patients also underwent subsequent arthroscopy, and the results were compared with MRI interpretations based on SMASH and fat-saturated T2-weighted images. RESULTS: We found no intraobserver variability between the interpretations of SMASH imaging and the interpretations of fat-saturated T2-weighted imaging. Of the 28 patients who also underwent subsequent arthroscopy, 19 were found to have full-thickness supraspinatus tendon tears and nine had superior labral anterior-to-posterior lesions. All arthroscopic findings correlated with prospective MRI interpretations. CONCLUSION: SMASH imaging allows significant time savings compared with fat-saturated T2-weighted MRI. We found that the use of the SMASH technique did not affect the MRI interpretation or the clinical outcome of patients.
Asunto(s)
Imagen por Resonancia Magnética/métodos , Articulación del Hombro/patología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Factores de TiempoRESUMEN
Two children presented with painful lytic lesions in the lower extremity. The lesions were located within cortical bone, and surrounded by sclerosis of the medullary bone and periosteal new bone formation. The lesions were painful, and nonsteroidal anti-inflammatory agents relieved the pain. CT-guided core biopsies were performed followed by radiofrequency treatment. Pathologic evaluation of the specimens revealed features consistent with benign intracortical chondroma. In one case radiofrequency treatment appears to have cured the tumor. The other patient required operative intervention.