ISSN:0899-3459    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

There have been multiple recent refinements in the arthroscopic techniques of meniscal surgery and anterior cruciate ligament (ACL) reconstruction, and these are now allowing many postoperative patients to resume an active lifestyle. A result is an increasing number of postoperative patients who are referred for a magnetic resonance (MR) scan of the knee because of a recurrent injury. In this article, we will discuss some of the MR findings of retorn menisci and the role of MR arthrography. We will also review the changes that occur in the MR appearance of the ACL graft during the first year after surgery, and its effect on the accuracy of diagnosing graft tears. The MR findings after other less common knee procedures will also be described.

ISSN:0899-3459    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Magnetic resonance (MR) imaging has emerged as the preferred modality for the imaging evaluation of musculoskeletal tumors. Although there is general agreement on the value of MR in diagnosis and staging, the use of intravenous contrast in the evaluation of musculoskeletal lesions remains controversial. The purpose of this review is to highlight these controversies, to put them in perspective, and to suggest recommendations for the use of gadopentetate dimeglumine. The following specific areas will be addressed: (a) evaluation of soft-tissue tumors, (b) diagnosis of low-grade chondrosarcoma and the use of contrast material in identification of intraosseous metastases, (c) monitoring response to chemotherapy, (d) evaluation for local recurrence after surgery and/or radiation therapy, and (e) selection of biopsy site.

ISSN:0899-3459    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Magnetic resonance (MR) arthrography is possible in any joint in which standard arthrography is performed. The diagnostic potential of this technique is optimized in the assessment of complex anatomical structures and intra-articular abnormalities that are difficult to visualize on conventional MR images. This paper presents the most common applications of MR arthrography in the shoulder, hip, knee, ankle, elbow and wrist, and explores the clinical indications in which MR arthrography adds the greatest benefit compared to standard arthrography and conventional MR imaging. Arthrographic MR images are most valuable in the evaluation of glenoid and acetabular labra, tendons of the rotator cuff, post-operative menisci, osteochondral fractures and loose bodies.

ISSN:0899-3459    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

One of the first musculoskeletal areas to be imaged by magnetic resonance (MR) was the hip. Early on, and even today, the most frequent indication for imaging of the hip has been for the evaluation of osteonecrosis and related diseases. Despite the long history of MR imaging of osteonecrosis, there still exist many controversies. This article will look at three of these: (a) What is the best way of imaging early osteonecrosis? This question has proven to be particularly important in the evaluation of the posttraumatic patient. We provide some preliminary evidence that the use of gadolinium-enhanced MR imaging may be helpful. Specifically, gadolinium fails to enhance areas of early osteonecrosis while surrounding uninvolved areas do enhance, (b) How should the patient with “MR bone marrow edema of the hip” be evaluated and treated? If there is radiographic osteopenia, the assumption is that this represents transient osteoporosis (a self-limited disease) and no treatment is necessary. However, if no osteopenia is present, the diagnosis and treatment become more problematic. A decision-making algorithm is presented to help overcome this dilemma. (c) Is documented osteonecrosis of the hip ever reversible without surgical intervention? Work done with renal transplant patients suggests that the answer to this question is yes, but work reported from Europe casts some doubt on this conclusion.

ISSN:0899-3459    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The “magic angle” effect in magnetic resonance (MR) imaging is caused by changes in the dipolar interactions between water hydrogen protons that are loosely bound along collagen fibrils in organized tissue such as tendon or articular cartilage. When tendons are aligned at 55° to the main magnetic field, the T2 relaxation time is lengthened, causing focal increased signal on short echo time MR images. Tendons in the ankle, wrist, and rotator cuff of the shoulder are common sites to observe this effect. Distinguishing magic angle effect from pathologic signal abnormalities due to degeneration or partial tears requires close comparison between T1− and T2-weighted images, as well as evaluation for secondary signs of injury such as tendon thickening or associated fluid.

ISSN:0899-3459    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

There is an increasing need for an accurate, noninvasive technique for the evaluation of cartilage. Magnetic resonance (MR) imaging, with its excellent contrast resolution and multiplanar imaging capability, was considered by many as the future gold standard for chondral imaging. Although substantial improvements in MR technology and understanding have occurred, the ideal imaging protocol and the role of MR imaging for cartilage evaluation has not been established. A confusing plethora of sequences have been advocated, with variable results and reproducibility. Often, techniques are not widely available or feasible from a practical point of view and many still require rigorous clinical evaluation. MR arthrography, although invasive and time consuming, provides excellent detailed evaluation of cartilage and can rival arthroscopy for the preoperative evaluation of traumatic ostechondral lesions or osteochondritis dissecans. Recently, encouraging results have been obtained with fat-suppressed imaging; however, further clinical trials are still awaited. This article attempts to place the various chondral MR imaging sequences in perspective, with discussion of their relative benefits and disadvantages.

ISSN:0899-3459    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Magnetic resonance (MR) imaging is a significant advance in musculoskeletal noninvasive visualization, especially for the soft tissues including the menisci. The purpose of this article is to give the radiologist a surgeon's perspective on the role of this technology in clinical practice. For MR imaging to be cost effective, it must accurately define anatomy, and reveal changes that have an impact on patient care—i.e., be clinically relevant. For MR imaging to be accurate, optimum software, hardware, and an experienced radiologist are essential. However, even if an MR examination has high accuracy, the abnormal findings of this evaluation may not be related to the clinical problem that the patient presents with. This is supported by the demonstration that asymptomatic patients may have grade 3 meniscal tears, hemiated discs, and rotator cuff changes. The MR examination may not change patient management even if it demonstrates pathologies such as a meniscal tear. The patient may tolerate the dysfunction and pain. The most cost-effective method of providing musculoskeletal care is still a careful history and competent physical examination.

ISSN:0899-3459    

出版商:OVID    

年代:1996

数据来源: OVID