Evaluation of the rotator cuff and glenoid labrum using a 0.2-Tesla extremity magnetic resonance (MR) system: MR results compared to surgical findings.

The purpose of this investigation was to evaluate the diagnostic capabilities of magnetic resonance imaging (MRI) performed using a dedicated-extremity MR system in detecting lesions of the rotator cuff and glenoid labrum. This retrospective study compared the MR results obtained in 47 patients that underwent MRI using a 0.2-Tesla extremity MR system (E-scan) to the surgical findings. MR images of the shoulder were obtained as follows: shoulder coil, T1-weighted, coronal-oblique and axial images; short Tau inversion recovery (STIR), coronal-oblique images; and T2-weighted, coronal-oblique, sagittal-oblique, and axial images. The MR examinations were interpreted by three highly experienced, musculoskeletal radiologists. Open surgical (N = 26) or arthroscopic (N = 21) procedures were performed within a mean time of 33 days after MRI. The surgical findings revealed rotator cuff tears in 28 patients and labral lesions in 9 patients. For the rotator cuff tears, the sensitivity, specificity, positive predictive value, and negative predictive value were 89%, 100%, 100%, and 90%, respectively. For the labral lesions, the sensitivity, specificity, positive predictive value, and negative predictive value were 89%, 95%, 80%, and 97%, respectively. The findings indicated that there was good agreement comparing the MR results obtained using the low-field extremity MR system to the surgical findings for determination of lesions of the rotator cuff and glenoid labrum. Notably, the statistical values determined for the use of this MR system were comparable to those reported in the peer-reviewed literature for the use of whole-body, mid- and high-field-strength MR systems.

Articular cartilage injuries of the knee: evaluation and treatment options.

Articular cartilage defects of the knee can be very debilitating, and diagnosis can be difficult because the symptoms are often nonspecific. Routine MRI scans, despite vast improvement in detection techniques, are often not sensitive or specific enough, especially for low-grade lesions. Therefore, articular cartilage injuries of the knee are often a diagnosis of exclusion requiring a thorough history, a good physical exam, and a high index of suspicion. Treatment of these injuries is still evolving, but new treatment options, including autogenous chondrocyte implantation, look promising, and long-term outcomes, while not yet complete, look encouraging.

MR imaging of the spine in sports injuries.

MR imaging has afforded an ability to better visualize and characterize a whole host of spine abnormalities encountered in the athletic population. It remains the mainstay in the noninvasive diagnosis of most soft-tissue abnormalities occurring within and about the spine. Its role in the evaluation of central spinal stenosis, the central spinal canal, and the spinal cord is unsurpassed by other noninvasive imaging modalities. In the setting of underlying fractures, it is complementary to CT, particularly with respect to evaluating concomitant soft-tissue and ligamentous abnormalities. With its ability to image edema and reactive marrow changes, it is useful in the evaluation of osseous stress changes that may occur in the athletic population.

MR imaging of the shoulder after an impingement test: how long to wait.

OBJECTIVE: The purpose of this study was to determine the appropriate minimum waiting time between an impingement test with subacromial injection and subsequent MR imaging to avoid misinterpretation if the injected fluid is still present. CONCLUSION: MR imaging should be delayed a minimum of 24 hr after a subacromial injection. Fluid in the subacromial space 24 hr after subacromial injection is unrelated to an impingement test.

Magnetic resonance imaging of the musculoskeletal system: the spine.

Magnetic resonance imaging in the patient who has had surgery is discussed. The most common indication for postoperative imaging is in the distinction between postoperative fibrosis and recurrent disc herniation. Magnetic resonance imaging is invaluable in the assessment of potential causes of failed back surgery syndrome such as postoperative infection, arachnoiditis and adjacent segment degeneration. Magnetic resonance imaging assumes a less important role in postoperative patients with metal hardware owing to image degradation secondary to metal artifact. Magnetic resonance imaging has a complementary role with computed tomography evaluation of spinal trauma. It excels at the noninvasive evaluation of spinal deformities and neoplasms.

Magnetic resonance imaging of the musculoskeletal system. Part 8. The spine, section 2.

Magnetic resonance imaging has revolutionized the noninvasive evaluation of degenerative disc disease and its complications. Compared with computed tomography and computed tomographic myelography, magnetic resonance allows specific determination of the nature of disc protrusions and other degenerative related soft tissues about the spine. Magnetic resonance offers the most complete evaluation of specific degenerative disorders including degenerative facet disease, spondylolysis, spondylolisthesis, spontaneous lumbar epidural hematomas, and juvenile discogenic disease.

Suprascapular nerve entrapment caused by supraglenoid cyst compression.

Twenty-two cases of suprascapular nerve entrapment caused by supraglenoid cyst compression were reviewed. Pain and weakness were the presenting symptoms in 14 shoulders and pain alone in 8. Twenty of the cysts were diagnosed by magnetic resonance imaging, and two were confirmed at surgical exploration. Electromyography of 20 shoulders was positive for neurologic involvement for both the infraspinatus and supraspinatus in 4 cases, for the infraspinatus only in 12, and negative in 4. Sixteen shoulders were treated by open excision, arthroscopy, or both. Superior labral lesions were diagnosed in 11 of 12 patients who underwent arthroscopy. At follow-up 10 of the patients who underwent surgery had complete resolution of symptoms, 5 had occasional pain or weakness, and 1 recurrence required a second surgery. Of six patients treated without surgery, two improved and four had no change. Supraglenoid ganglion cysts are common and can easily be diagnosed by magnetic resonance imaging. For patients with symptoms arthroscopy with repair of the superior labral lesion and either arthroscopic debridement or direct open decompression and excision of the cyst is recommended.

Magnetic resonance imaging of the musculoskeletal system. Part 8. The spine, section 1.

Magnetic resonance has assumed a preeminent role in the imaging evaluation of the spine. Owing to its multiplanar capability and superior soft tissue contrast, magnetic resonance imaging is the procedure of choice for a host of spinal disorders including degenerative disc disease, tumor evaluation, trauma, and spinal deformities. It represents the most accurate means of distinguishing between recurrent disc herniation and epidural fibrosis, and it excels at the assessment of many postoperative abnormalities such as infection, adjacent segment disc degeneration, and arachnoiditis. Magnetic resonance imaging is also helpful in the evaluation of numerous diagnostic challenges that are less well resolved by other means. This includes the distinction between disc herniation and epidural hematoma, synovial cyst from nonspecific fibrous thickening of a facet capsule, and the evaluation of numerous other soft tissue abnormalities. Computed tomography, computed tomography myelography, and scintigraphy continue to be useful for numerous specific disorders and in those patients with metal hardware or contraindications to magnetic resonance scanning. Overall, however, magnetic resonance is the imaging procedure preferred for many spinal disorders. This article is the first installment of a 3-part series discussing the role of magnetic resonance imaging of spinal disorders. Section 1 will describe the varying imaging modalities available and their relative advantages and disadvantages. A consideration of magnetic resonance imaging techniques will follow, followed by a discussion of the imaging manifestations of early degenerative disc disease. Section 2 will be devoted to an in depth discussion of specific pathologic processes encountered in patients with degenerative disc disease. Section 3 will end the series with a consideration of postoperative imaging followed by a discussion of spinal deformities, trauma, and neoplasms.

Chronically injured posterior cruciate ligament: magnetic resonance imaging.

Magnetic resonance imaging has been said to be highly reliable for diagnosis of acute posterior cruciate ligament insufficiency. In the present study, 13 patients whose posterior cruciate ligament insufficiency had been documented by magnetic resonance imaging within 10 weeks of the acute injury were recalled for a followup examination and magnetic resonance imaging. The followup interval ranged from 5 months to 4 years. In only 23% of the cases did the posterior cruciate ligament still appear discontinuous on followup magnetic resonance imaging. In the remaining 77%, the posterior cruciate ligament was continuous from tibia to femur, although it appeared abnormally arcuate or hyperbuckled. Conventional interpretation of these magnetic resonance images would suggest that the posterior cruciate ligament had healed. Nevertheless, by clinical examination results, these same patients all were judged to have posterior cruciate ligament insufficiency. Thus, it was concluded that although magnetic resonance imaging may be reliable for evaluation of acute posterior cruciate ligament injury, magnetic resonance imaging findings should not be used to infer functional status in chronic cases.

Occult osseous lesions associated with anterior cruciate ligament tears.

Occult osseous lesions occurring with anterior cruciate ligament tears have been described only recently. Twenty patients with complete anterior cruciate ligament disruptions and evidence of occult osseous lesions on their preoperative magnetic resonance (MR) images were evaluated retrospectively at 24- to 73-months' followup to document the natural history and long-term effects of the lesions. Thirty-seven initial osseous signal abnormalities were documented on the MR images of 20 patients. All 20 patients had lesions in the posterolateral tibial plateau, and 13 had additional lesions in the lateral femoral condyle. Twenty-four of the 37 osseous lesions appeared resolved on followup MR images, and 13 had become sclerotic. Lesions of the lateral tibial plateau were especially likely to be sclerotic at followup. This study reaffirms the specificity of bone signal abnormalities of the posterolateral tibial plateau and lateral femoral condyle in association with complete anterior cruciate ligament tears. The data indicate that a proportion of anterior cruciate ligament patients will incur progressive articular cartilage abnormalities, although case-by-case predictions based on initial MR images would be unreliable.

MRI of the shoulder.

MRI of the shoulder is widely considered the imaging modality of choice in the evaluation of shoulder pain and the clinical impingement syndrome. This is because of its direct evaluation of all of the soft tissue structures of the subacromial space, as well as its ability to depict the relationship of the overlying osseous and soft tissue structures of the coracoacromial arch. It also provides information regarding the capsulolabral anatomy and, with the addition of MR arthrography, is becoming recognized as the imaging modality of choice for instability workup. MRI evaluation, when combined with the always important clinical history, physical examination, and radiographs, provides the referring clinician and orthopedic surgeon with the most anatomic and pathological information possible. This, in turn, allows the most informed decision making possible regarding conservative management or surgical treatment.

Radial tears of the menisci: MR findings.

Radial meniscal tears have a plane of cleavage oriented across the short axis of the meniscus in the same plane in which radial images are oriented. These tears are important to recognize, because they have clinical implications different from those of other meniscal tears with respect to meniscal function, orthopedic treatment, and clinical course. Depending on their size, location, and orientation, radial tears can have different appearances on standard MR images. Certain types can be fairly subtle to diagnose. The purpose of this essay is to illustrate the varied appearances of radial tears on MR images and the findings commonly associated with radial tears.

MRI findings of acute turf toe. A case report and review of anatomy.

Normal anatomy of the metatarsophalangeal joint of the hallux has been well described. However, the pathologic anatomy of turf toe, a common injury among football and rugby players, has not been documented in detail. Magnetic resonance images (MRI) of a classic case of turf toe were examined and the findings were compared with MRI of a normal specimen and correlated with known features of gross anatomy. MRI findings confirmed that turf toe involves a sprain or tear of the plantar metatarsophalangeal joint capsule.

[Evaluation of the rotator cuff with magnetic tomography]. / Evaluering av skulderens rotatormuskulatur med magnettomografi.

Rotator cuff tears are difficult to diagnose clinically, both in the acute and the chronic phase. Both conservative and surgical treatment give the best results if the injury is detected early. Magnetic resonance imaging (MRI) has recently been introduced for diagnoses of cuff tears. The purpose of this study was to establish the accuracy of MRI in relation to surgical findings in the same patient group. MRI was used in the diagnosis of 25 patients who later underwent surgery for injury to the rotator cuff. During the surgery, 19 total tears were identified, of which 15 had been described by MRI. MRI showed a sensitivity of 79% and a specificity of 83%. The predictive value of a positive test was 83%. In experienced hands, MRI is extremely accurate for detecting rotator cuff injuries, but ultrasonography should still be the first method of diagnosis in Norway, because of its accuracy when used by experienced practitioners, and its availability and low cost.

Osteochondral lesions and cruciate ligament injuries. MRI in 18 knees.

Magnetic resonance images were obtained prior to arthroscopy and surgery in 18 knees with acute anterior cruciate ligament injury. The incidence of osseous lesions was assessed and the findings were compared with those at arthroscopy. A total of 28 osseous lesions were detected by MRI in 15 knees, but none of these were detected by radiographs or arthroscopy.

Diagnosis of meniscal and cruciate ligament tears using MRI. Evaluation of two scanning techniques.

The accurate diagnosis of meniscal and cruciate ligament tears is essential for proper management of knee injuries. In recent years, magnetic resonance imaging has been increasingly used to diagnose knee pathology. Several articles have documented the accuracy of MRI, but conflicting results have been reported. We present a series of 50 consecutive patients who underwent both MRI and complete arthroscopy. We tested two different scanning protocols and found the higher-resolution scanning protocol to be more accurate, resulting in fewer discrepancies between the results of MRI and arthroscopy, which we used as the standard for comparing the MRI interpretations. Magnetic resonance imaging is an important diagnostic tool in orthopedic practice. It is available, accurate, and well-accepted by patients. However, as demonstrated by the results of this study, the accuracy of MRI is highly dependent upon the scanning protocol used.

MR of osteochondritis dissecans and avascular necrosis of the mandibular condyle.

We studied 40 patients exhibiting radiologic changes of either osteochondritis dissecans (OCD) or avascular necrosis (AVN) involving the mandibular condyle to evaluate the structural changes associated with these lesions when using high-field-strength MR imaging. Various clinical indications for imaging each patient with routine radiography, tomography, and surface-coil MR included headache, temporomandibular joint (TMJ) and/or ilsilateral facial pain, joint crepitus, clicking, locking, and either recently acquired or changing (unstable) occlusal disorder. Radiologic findings included alterations in condyle morphology and MR signal characteristics compatible with either OCD or AVN or, in some cases, both. Previous nonsurgical mandibular trauma was temporally related to the onset of symptoms in eight patients. Five patients exhibiting either unilateral or bilateral AVN involving the condyles and condylar necks had undergone previous orthognathic surgery, including sagittal split mandibular osteotomies followed by intermaxillary fixation. One patient exhibiting condylar AVN with articular surface collapse and osseous destruction had undergone previous TMJ meniscectomy followed by insertion of a permanent Proplast implant. Thirty-one of 34 patients with no prior surgery and MR changes of condylar OCD/AVN had associated internal derangement of the TMJ meniscus. There was surgical confirmation of findings in 10 joints. We assert that OCD and AVN are relatively common, clinically significant lesions of the mandibular condyle often associated with preexisting internal derangement of the temporomandibular joint.

The diagnosis of temporomandibular joint disease: two-compartment arthrography and MR.

The reliability and accuracy of two-compartment temporomandibular joint (TMJ) arthrography was compared with MR imaging on the basis of an analysis of surgical findings obtained from joints that had been studied preoperatively with arthrography or MR or, in some cases, both procedures. Seven hundred forty-three consecutive TMJ arthrograms were successfully obtained in a total of 443 patients by using a single 27-gauge needle and a two-compartment technique in each joint. There was a 100% correlation with surgical findings in 218 radiologically abnormal joints operated on within 90 days of arthrography with respect to the presence or degree of meniscus displacement and normal or abnormal disk morphology and function. In 604 patients 1052 TMJs were studied with high-field-strength surface-coil MR. Surgical findings were available for correlation in 170 of the joints studied. Forty-three joints were studied with both two-compartment arthrography and MR. Eight operated joints had been imaged successfully with both two-compartment arthrography and MR. Both methods of evaluation provided highly reliable and accurate information regarding meniscus position and shape. Arthrography was superior to MR in detecting capsular adhesions and the presence or absence of perforation of the disk or meniscus attachments. Simple meniscectomy (with or without insertion of a temporary Silastic TMJ implant) was the most frequently performed surgical procedure in the series, followed by meniscus repositioning procedures. Joint effusions, failed TMJ implants, and avascular necrosis were demonstrated best with MR. Soft-tissue lesions, including intrinsic degeneration of the meniscus, anomalous muscle development, muscle atrophy, tendinitis, and injuries such as contusions and hematomas, were demonstrated only with MR. Partial-flip-angle GRASS (gradient-recalled acquisition in the steady state) techniques permit both fast scanning and study of functional joint dynamic. Joint fluid may appear as high signal intensity on GRASS images because of T2*-weighting. We recommend MR as the procedure of choice for diagnosis of uncomplicated internal derangements of the TMJ. Two-compartment arthrography with videofluoroscopy is an important ancillary procedure that should be performed whenever capsular adhesions or perforations are suspected and not demonstrated with MR and whenever MR is inconclusive.

Three-dimensional computed tomography in maxillofacial surgical planning.

Fifty-four maxillofacial three-dimensional computed tomographic examinations were performed during a 12-month period for the purpose of surgical planning. Pathologic entities in the series included trauma, neoplasia, cleft palate, and other developmental anomalies. Computer-assisted mandibular disarticulation was performed routinely after each study to permit direct viewing of the mandible or maxilla in isolation. Three-dimensional computed tomography is a useful technique for maxillofacial surgical planning.