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Biomedical subjects

J Beltran

Publications and source records attributed to J Beltran.

At least 91 records · Page 5Linked to original sources
PubMed1988

Pitfalls in MR imaging of the knee.

Discrepancies between the findings of magnetic resonance (MR) imaging and those of arthroscopy were reviewed retrospectively in 52 knee examinations. Some of the discrepancies between MR imaging and arthroscopy were caused by errors in interpretation of MR images due to normal structures that mimicked meniscal tears. The transverse ligament and the lateral inferior genicular artery can produce the appearance of tears in the anterior horns of the medial and lateral menisci, respectively. The popliteus tendon may be mistaken for a tear in the posterior horn of the lateral meniscus. The normal concavity at the outer edge of the meniscus can create a volume-averaging artifact, which mimics a horizontal tear in the meniscus. Tears of the meniscus and separations of the meniscus from the joint capsule were not seen or were underestimated when the tears were oriented parallel to the plane of the image. An awareness of these pitfalls may improve the accuracy of the interpretation of MR images of the knee.

Adolescent↗
PubMed1987

Avascular necrosis of the femoral head: early MRI detection and radiological correlation.

Magnetic Resonance Imaging (MRI) and conventional radiographs were compared in 49 hips with Avascular Necrosis (AVN). MRI detected AVN in 25% of the hips during the preradiological stage of the disease. Both MRI and conventional radiographs accurately detected AVN in the remaining 75% of hips. Correlation between the patterns observed with the two techniques reflected the underlying histopathologic events. The reactive interface between infarcted bone and viable bone could be identified on MRI as a low signal intensity (SI) band. On conventional radiographs the reactive interface appeared as a sclerotic band. The adjacent hyperemic zone was seen on MRI as a high SI band and as a lucent zone on the plain films. Variations of this pattern occurred as related to the extend and duration of AVN and to the individual's ability to mount a healing response. Minor degrees of collapse of the femoral head were better identified with plain radiographs but MRI demonstrated small areas of hyperintensity probably corresponding to early subchondral fractures.

Femur Head Necrosis↗
PubMed1987

Increased MR signal intensity in skeletal muscle adjacent to malignant tumors: pathologic correlation and clinical relevance.

Increased signal on T2-weighted magnetic resonance (MR) images has been demonstrated in skeletal muscle adjacent to neoplasms. Clinical significance of this sign was evaluated by reviewing MR images of 50 patients with musculoskeletal disorders. Increased signal in adjacent muscle was present in 22 patients, including 13 of 25 with primary or secondary malignancies of the musculoskeletal system. Biopsy specimens from the affected area in 11 of these 13 patients revealed edema (n = 8) more often than tumor invasion (n = 3). Nine of 25 patients with nonneoplastic processes had increased signal intensity in skeletal muscle because of infection, myositis, or hematoma. In patients who have not undergone previous surgery or radiation therapy and are without an inflammatory mass, increased signal intensity may be a useful indicator of malignancy.

Bone Neoplasms↗
PubMed1987

Tumors of the osseous spine: staging with MR imaging versus CT.

Twelve patients with tumors involving the osseous spine were evaluated with magnetic resonance (MR) imaging and computed tomography (CT), six with and six without intrathecal injection of contrast material. MR imaging was found to be superior to CT without contrast material and equal to CT with contrast material in delineating the anatomic relationships of the tumors, including bone involvement, spinal canal invasion, paraspinal soft-tissue extension, and vascular involvement. Since MR imaging can provide most of the anatomic information necessary for treatment planning, intrathecal injection of contrast material can be avoided in most instances when evaluating tumor involvement of the osseous spine. However, CT without contrast medium was superior to MR imaging in showing critical cortical bone destruction and calcified tumor matrix.

Humans↗
PubMed1987

Tendons: high-field-strength, surface coil MR imaging.

High-resolution magnetic resonance (MR) images of the tendons of the hands, wrists, feet, and ankles of six healthy volunteers and six cadavers were obtained using receive-only surface coils and reduced-field-of-view imaging. Normal anatomy was identified and compared with gross anatomic sections of the six cadavers. Experimentally produced tears of the calcaneal (Achilles) tendon in domestic swine were identified on MR images. The hands and feet of 11 patients were examined, and a variety of pathologic lesions were identified, including acute posttraumatic rupture, acute tenosynovitis, chronic tendonitis, and postsurgical complications. MR imaging provides inherently greater soft-tissue contrast than any other currently available imaging modality. With the use of surface coils and reduced-field-of-view imaging to enhance spatial resolution, MR imaging has become a valuable tool for imaging tendons. Advantages over other available modalities include excellent depiction of anatomic detail, superior contrast resolution, and the potential for multiplanar imaging.

Animals↗
PubMed1987

Infections of the musculoskeletal system: high-field-strength MR imaging.

Twenty-two patients with clinical findings consistent with osteomyelitis, soft-tissue infection, or both were studied with magnetic resonance (MR) imaging at 1.5 T. Another 15 patients with joint effusion but no clinical or laboratory signs of infection served as controls. Soft-tissue abscesses, osteomyelitis, joint and tendon sheath effusion, and cellulitis were well depicted on MR imaging, allowing the correct diagnosis of presence and extent of infection in all but two cases. MR imaging was as sensitive as technetium-99m methylene diphosphonate bone scintigraphy in demonstrating osteomyelitis and was more specific and more sensitive than other scintigraphic techniques in demonstrating soft-tissue infections, primarily because of its superior spatial resolution. Computed tomography, performed in seven cases, was as accurate as MR imaging in demonstrating bone and soft-tissue infections. Infected and noninfected synovial effusions had the same signal intensity, but associated findings such as soft-tissue fluid collections or osteomyelitis made the distinction possible.

Abscess↗
PubMed1987

Rheumatoid arthritis: MR imaging manifestations.

Radiologic assessment of the stage and treatment response of rheumatoid arthritis (RA) is based on the presence of bone erosions, joint-space narrowing, and osteoporosis. Most radiologic methods for staging RA lack interobserver correlation and are time consuming. Magnetic resonance (MR) imaging provides excellent depiction of soft-tissue abnormalities of the joints affected by RA, which allows detection of early changes. Nineteen joints of 17 patients with RA were studied with surface-coil MR imaging. Measurable abnormalities demonstrated by MR imaging but not clearly seen on plain radiographs included bone erosions, joint effusion, synovial sheath effusion, and cartilage irregularity and thinning. Seven patients of this group underwent MR imaging before and after 6 months of gold therapy. Four patients had significant interval changes on MR images that were not seen on plain radiographs. MR imaging may become a sensitive and objective method for quantitative assessment of the joint changes of RA.

Adult↗
PubMed1986

Joint effusions: MR imaging.

Magnetic resonance (MR) images of the hips and knees of three healthy volunteers were reviewed and compared with images obtained from the hips of three patients with effusions. Comparison was also made with MR images obtained from two swine knees following the injections of saline in one and blood in the other. The anatomy of the knees and hips was well defined. The hip effusions were all easily recognized. MR images of the swine knees clearly demonstrated the experimentally produced joint effusions. The hip effusions and the experimentally introduced blood and saline all had long T1 and T2 values allowing easy differentiation from articular cartilage. We were unable to distinguish fresh blood from saline in the knee joints.

Adult↗
PubMed1986

Aneurysmal bone cysts: MR imaging at 1.5 T.

Two patients with aneurysmal bone cysts of the pelvis were imaged using a 1.5-T magnetic resonance imaging device. Findings included multiple internal septations, cysts with fluid-fluid levels of varying intensity, and an intact rim of low-intensity signal completely surrounding the lesion. These findings allow a specific diagnosis of aneurysmal bone cyst to be made.

Adolescent↗
PubMed1986

Meniscal tears: MR demonstration of experimentally produced injuries.

Magnetic resonance (MR) imaging was performed using a 1.5-T magnet on eight immature swine knees with surgically produced vertical and horizontal meniscal tears. Three radiologists, interpreting the images independently, detected all tears. Tears in the middle portion of the meniscus were best seen on sagittal views, while lesions of the anterior and posterior horns of the meniscus were best seen on coronal views. MR has several advantages over arthrography, the current diagnostic method for knee injuries: it is noninvasive, uses no ionizing radiation, and provides excellent soft-tissue contrast resolution.

Animals↗
PubMed1986

The knee: surface-coil MR imaging at 1.5 T1.

Seven normal knees (in five volunteers) and seven injured knees (in seven patients) were examined by high-resolution magnetic resonance (MR) imaging at 1.5 T with a surface coil. Seven medial meniscal tears, three anterior cruciate ligament tears, one posterior cruciate ligament avulsion, an old osteochondral fracture, femoral condylar chondromalacia, and one case of semimembranous tendon reinsertion were identified. MR images correlated well with recent double-contrast arthrograms or results of surgery. All tears were identified in both the sagittal and coronal planes. Because of its ability to demonstrate small meniscal lesions and ligamentous injuries readily, MR imaging with a surface coil may eventually replace the more invasive arthrography.

Humans↗
PubMed1986

High-field MR surface-coil imaging of the hand and wrist. Part I. Normal anatomy.

High-resolution magnetic resonance (MR) images of the hands and wrists of six healthy volunteers were obtained at 1.5 T with a surface coil. Additionally, the hands and wrists of two fresh cadavers were imaged and were subsequently sectioned for anatomic correlation. High contrast when depicting soft-tissue, coupled with impressive spatial resolution and multiplanar capabilities, enabled delineation of fine structures including nerves, tendons, and blood vessels. Osseous and cartilaginous structures were also well depicted. MR imaging gives anatomic definition of the hand and wrist unmatched by other diagnostic imaging methods.

Adult↗
PubMed1986

High-field MR surface-coil imaging of the hand and wrist. Part II. Pathologic correlations and clinical relevance.

High-resolution magnetic resonance (MR) images of the hands and wrists of 12 patients with a variety of suspected pathologic conditions were obtained at 1.5 T using a prototype surface coil. Lesions included ganglions, rheumatoid arthritis, carpal fractures, carpal tunnel syndrome, and arteriovenous malformations. In the selected cases studied, MR images provided potentially relevant information. Surgical, pathologic, and radiographic correlations were obtained. MR imaging affords delineation of soft-tissue structure that is unmatched by other imaging methods, including computed tomography. It is anticipated that MR imaging of the hand and wrist will afford sufficient valuable clinical information in certain conditions to justify its expense outside a research setting. Further clinical testing, however, is warranted.

Adult↗
PubMed1986

Rotator cuff lesions of the shoulder: evaluation by direct sagittal CT arthrography.

Direct sagittal computed tomographic scanning (DSCT) of the shoulder was performed in 42 symptomatic patients, six healthy volunteers, and two cadaver shoulders. Axial CT scanning and double-contrast arthrography with plain radiographs were performed in 41 patients for comparison. DSCT enabled correct identification of 27 of 29 lesions in 24 patients. Seventeen patients had normal shoulders. Axial CT scanning and DSCT together enabled correct identification of all lesions and were markedly superior to plain-film arthrography. DSCT enabled diagnosis of all cases of complete rotator cuff tear plus three cases of incomplete tear and three of rotator cuff atrophy not identified by the other techniques. Axial CT scanning was better than DSCT for diagnosis of Bankart lesions.

Adolescent↗