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Biomedical subjects

J Beltran

Publications and source records attributed to J Beltran.

At least 55 records · Page 3Linked to original sources
PubMed1997

MR imaging of pediatric elbow fractures.

Pediatric elbow fractures are elusive to radiographic detection and more sophisticated imaging techniques are often required to assess the presence and extension of the fracture line to make appropriate treatment decisions. Arthrography is the current method of choice, but ultrasonography and, more recently, MR imaging have been proposed as alternative modalities, although further experience is necessary to validate their usefulness. We believe that MR imaging offers significant benefits because of its exquisite spatial and contrast resolution.

Aged↗
PubMed1996

Moderate primary pulmonary hypertension in patients undergoing liver transplantation.

Primary pulmonary hypertension (PPH) in patients with hepatic cirrhosis is often considered an unacceptable condition for liver transplantation because of increased morbidity and mortality during the procedure. We studied the incidence, characteristics, and final outcome of patients with PPH undergoing liver transplantation in our institution. Among the 226 patients undergoing 257 liver transplantations, eight (3.5%) fulfilled the conditions of PPH and responded to vasodilator therapy. Nitroglycerin 1.5 micrograms/kg produced a decrease in pulmonary vascular resistance index (PVRI) and mean pulmonary arterial pressure (MPAP) of 20% and 15%, respectively. Patients with PPH when compared with a matched group of patients without PPH had markedly increased hemodynamic changes in PVRI (P = 0.004) and MPAP (P = 0.0001) during and after the procedure. All patients with PPH required pulmonary vasodilator therapy after reperfusion of the new liver, while none in the group of patients without PPH required this therapy. Furthermore, after graft reperfusion, patients with PPH in which venovenous bypass was not used (n = 3), had a more compromised right ventricular function with a greater increase of central venous pressure (CVP) (90%) and MPAP (140%) when compared with patients with bypass or preservation of the recipient's vena cava (n = 5) in whom the increase of CVP and MPAP was 50% and 60%, respectively. Moderate PPH without a fixed level of pulmonary hypertension in patients undergoing liver transplantation is not related to an adverse outcome.

Adult↗
PubMed1995

MR imaging of the elbow: normal variant and potential diagnostic pitfalls of the trochlear groove and cubital tunnel.

The proximal portion of the ulna includes the olecranon and the coracoid process, which together form the trochlear groove that articulates with the distal humerus. The groove is constricted at the junction of the olecranon and the coracoid process. A thin, transverse, nonarticular ridge intersects the groove at this junction. Both the constriction of the groove and the nonarticular ridge may simulate disease on MR imaging of the elbow.

Adult↗
PubMed1995

Posterior intermalleolar ligament of the ankle: normal anatomy and MR imaging features.

OBJECTIVE: The purposes of this study were to delineate the normal anatomy and MR imaging features of the posterior intermalleolar ligament--a normal ligamentous variant of the posterior portion of the ankle--and to identify normal anatomic characteristics that may account for the role of the ligament in the development of posterior impingement syndrome. MATERIALS AND METHODS: The prevalence, size, and shape of the posterior intermalleolar ligament were documented in 36 cadaveric ankles and in 97 MR studies of the ankle in patients with and without symptoms. RESULTS: The posterior intermalleolar ligament was identified in 20 (56%) of the 36 cadaveric feet. It was 1-8 mm wide, and its diameter (anterior to posterior) was 5-8 mm. The ligament often resembled a meniscus, and in one case its anterior lip herniated into the ankle joint. The posterior intermalleolar ligament was detected in 18 (19%) of the 97 MR studies of the ankle. It was visualized on coronal T1- or T2-weighted images as a distinct, hypointense band traversing between the posterior talofibular ligament and the inferior transverse ligament. CONCLUSION: The posterior intermalleolar ligament is a normal variant of the posterior ligaments of the ankle and is present in a significant number of persons. It is best seen on coronal T1- and T2-weighted MR images. Its meniscuslike shape and occasional extension into the ankle joint may account for the development of posterior impingement syndrome in susceptible persons.

Adolescent↗
PubMed1995

Osteosarcoma: subtle, rare, and misleading plain film features.

Osteosarcoma is a malignant, mesenchymal, osteoid, and bone-forming tumor [1-3]. In most cases, typical radiographic features clearly illustrate the aggressive bone-forming nature of the lesion. These features include long-bone metaphyseal location, mixed areas of lysis and sclerosis, cortical destruction, periosteal new bone, and soft-tissue mass. However, numerous factors contribute to misleading radiographic patterns of osteosarcoma. They include histologic low-grade, lytic, or minimally sclerotic lesions, early detection, confinement to the intramedullary canal, benign-appearing periosteal reaction, rare intraosseous locations (subchondral, diaphyseal, intracortical), and rare skeletal sites (e.g., soft tissues, skull, ribs, tarsal bones). Secondary osteosarcomas, such as those arising from infarcts or fibrous dysplasia, may also produce a confusing radiologic picture. The purpose of this pictorial essay is to illustrate cases of osteosarcoma that proved to be difficult diagnostic dilemmas because of their subtle, rare, or misleading plain film features.

Adolescent↗
PubMed1995

MR imaging of soft-tissue infection.

MR imaging is the ideal technique to display the soft-tissue abnormalities produced by infectious processes. In general these soft-tissue alterations consist of signal intensity changes that reflect the increased water content of the soft tissues induced by the inflammatory reactions. In some cases these changes are nonspecific, but in others, MR imaging can be quite specific and helpful in detecting the presence and extent of the infection, which generally is suspected clinically on the basis of physical and laboratory findings. The MR manifestations of soft-tissue infection, including septic arthritis, tenosynovitis, bursitis, cellulitis, necrotizing fascitis, soft-tissue abscess, infectious myositis, HIV-related infection, lymphadenitis and lymphangitis, and a few unusual parasitic and fungal infections, are reviewed.

AIDS-Related Opportunistic Infections↗
PubMed1994

Pediatric elbow fractures: MRI evaluation.

Magnetic resonance imaging (MRI) was performed in eight patients under the age of 8 years who suffered elbow fractures, to assess possible fracture extension into the distal nonossified epiphysis of the humerus in seven cases and to determine the displacement and location of the radial head in one case. MRI allowed accurate depiction of the fracture line when it extended into the cartilaginous epiphysis. In four cases, MRI findings were confirmed at surgery. In five cases, surgery was obviated because no articular extension of the fracture was seen on MRI (4 cases) or because no displacement was noted (1 case). In one patient, the plain film diagnosis of a Salter type II fracture was changed to Salter type IV on the basis of the MRI findings. It is concluded that MRI might play a role in the preoperative evaluation of pediatric patients presenting with elbow trauma when extension of the fracture cannot be determined with routine radiographic studies. Elbow injuries in children may be difficult to diagnose by routine clinical and radiographic techniques [1, 4, 12, 14]. Diagnostic difficulty is due to the presence of multiple ossification centers of the distal humeral epiphysis and proximal radius and ulna; these are mostly cartilaginous until the age of 11-12 years and therefore invisible on radiographs. Following distal radial and distal tibial physeal fractures, epiphyseal elbow injuries are the most frequent epiphyseal injuries [8, 16]. These fractures tend to be unstable and often require surgical intervention. In addition, lasting sequelae such as cubitus valgus and delayed ulnar nerve palsy can occur if these fractures are not treated properly [8].(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1994

Pseudodefect of the capitellum: potential MR imaging pitfall.

PURPOSE: To describe the pseudodefect of the distal humerus at the junction of the capitellum and lateral epicondyle, which may simulate an osteochondral lesion on axial and coronal magnetic resonance (MR) images. MATERIALS AND METHODS: MR imaging studies of the elbow in 32 patients and 22 asymptomatic volunteers were retrospectively reviewed. Thirty-two human humeri were also examined for normal anatomy of the junction of the capitellum and distal humerus. RESULTS: Twenty-two of the clinical MR examinations and 14 of the studies on volunteers revealed the presence of the pseudodefect. A groove at the junction and the overhanging lateral edges of the capitellum account for the appearance of this pseudolesion. CONCLUSION: Familiarity with the characteristic appearance and location of this pseudodefect will prevent its misinterpretation as an osteochondral fracture of the distal humerus.

Adolescent↗
PubMed1994

Diagnosis of compressive and entrapment neuropathies of the upper extremity: value of MR imaging.

Compressive and entrapment neuropathies (CENs) are relatively common clinical syndromes characterized by neurologic manifestations caused by mechanical or dynamic compression of peripheral nerves. Radiologists are often required to evaluate CENs primarily to rule out soft-tissue lesions as a potential cause of the syndrome. MR imaging has become the best technique for accurate delineation of soft-tissue lesions, and it is ideally suited for the assessment of CEN. Although many CENs of the upper extremity have been described in the clinical literature, only a few of them have received attention in radiologic publications. This review focuses on the most common CENs involving the upper extremity, with special emphasis on the MR manifestations.

Arm↗
PubMed1994

Magnetic resonance imaging of bone marrow disorders of the knee.

Bone marrow abnormalities around the knee are encountered frequently when performing MR imaging. Some of these so-called abnormalities may represent normal variations of the bone marrow contents and have no clinical significance. On other occasions, MR imaging may be the only technique that demonstrates a bone marrow lesion. Edema, osteonecrosis, infection, and tumor are entities frequently detected and assessed with MR imaging. We now, perhaps for the first time, are able to visualize and assess directly the bone marrow and its disorders. Knowledge of normal anatomy, variants, and pathologic signs coupled with meticulous imaging techniques are of paramount importance for accurate interpretation of such MR images.

Bone Marrow↗
PubMed1994

Sinus tarsi syndrome.

Sinus tarsi syndrome is a clinical-pathologic entity with characteristic MR imaging manifestations related to the inflammatory changes and ligamentous tears occurring in the hindfoot. Frequently, this entity is associated with other tendon and ligamentous injuries of the ankle. Radiologists should be aware of this condition to direct their search to the specific MR imaging findings.

Foot↗
PubMed1994

Contrast enhancement in musculoskeletal imaging. Current status.

This article discusses intravenous and intra-articular uses of contrast in cross-sectional imaging for the evaluation of musculoskeletal abnormalities. Emphasis will be placed upon the important traditional uses of contrast-enhanced computed tomography and the recent developments in contrast-enhanced magnetic resonance imaging.

Contrast Media↗
PubMed1993

Eosinophilic granuloma: MRI manifestations.

The appearance on magnetic resonance imaging (MRI) of 16 cases of pathologically proven eosinophilic granuloma were reviewed retrospectively and correlated with the radiographic appearance of the lesion. The most common MR appearance (ten cases) was a focal lesion, surrounded by an extensive, ill-defined bone marrow and soft tissue reaction with low signal intensity on T1-weighted images and high signal intensity on T2-weighted images, considered to represent bone marrow and soft tissue edema (the flare phenomenon). The MRI manifestations of eosinophilic granuloma, especially during the early stages, are nonspecific, and may stimulate an aggressive lesion such as osteomyelitis or Ewings sarcoma, or other benign bone tumors such as osteoid osteoma or chondroblastoma.

Adolescent↗
PubMed1993

The elbow: MR features of nerve disorders.

The authors retrospectively reviewed 15 magnetic resonance (MR) studies of elbows with radiographic evidence of nerve disorders. These 15 cases were selected from 55 MR studies of the elbow in patients referred for various complaints. MR images of the elbow of 10 healthy volunteers were also reviewed. Ulnar nerve disorders were seen in 11 cases. Three patients had median nerve disease, and one patient had a pathologic condition of the radial nerve. The following nerve abnormalities were detected: focal or diffuse nerve thickening, increased signal intensity on T2-weighted images, and course deviation due to either mass effect or spontaneous subluxation. Six of seven patients with nerve thickening, two of two patients with increased nerve signal intensity, and five of eight patients with nerve displacement complained of neurologic symptoms. Four of the patients underwent surgery; in each, surgical results confirmed the findings at MR. These results suggest that MR imaging has a potential role in the detection of nerve disorders at the elbow and in the guidance of treatment.

Adult↗
PubMed1993

Trispiral tomography and magnetic resonance imaging of the wrist.

Tomography, which permits a far more accurate visualization of lesions than conventional radiographs, is conducted via several different methods, depending on the specific movement of the x-ray tube. Linear tomography is the simplest method but produces images that appear streaked. Zonotomography, which uses an elliptical or figure-8 movement of the x-ray tube, creates a uniform blurring of structures and a much clearer resolution of the plane of focus. Even sharper images are produced by multidirectional trispiral tomography, which is described as well as its application to specific anatomic areas of the wrist. The normal anatomy and a variety of problems of the wrist as visualized with magnetic resonance imaging are also described.

Carpal Bones↗