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Biomedical subjects

T Laor

Publications and source records attributed to T Laor.

31 records · Page 2Linked to original sources
PubMed1996

MR imaging in congenital lower limb deformities.

Treatment for children with congenital deformities of the lower extremities may vary, depending on the state of the unossified skeletal structures and surrounding soft tissues. The purpose of our study was to demonstrate the spectrum of the osteochondral and extrasosseous abnormalities as depicted with MR imaging. We retrospectively reviewed MR examinations of 13 limbs of ten children (aged 1 month-9 years, mean 2.1 years) with longitudinal and transverse deformities of the lower extremities. The lesions imaged were fibular hemimelia (n = 5), tibial hemimelia (n = 5), and congenital constriction bands (n = 3). Each examination was assessed for abnormalities in the osteocartilaginous and extraosseous (articular or periarticular components such as ligaments, tendons, and menisci; the muscles and the arteries) structures. Abnormalities were seen in all patients. Osteocartilaginous abnormalities in the patients with longitudinal deformities included abnormal distal femoral epiphyses, abnormal proximal tibial physes, hypertrophied and dislocated proximal fibular epiphyses, unsuspected fibular and tibial remnants, and absence or coalition of the tarsal bones. No osteocartilaginous abnormalities were seen in the patients with congenital constriction bands. Articular abnormalities about the knee in patients with either form of hemimelia included absent cruciate ligaments and menisci, dislocated or absent cartilaginous patellae, absent patellar tendons, and abnormal collateral ligaments. All but one limb imaged had absent or attenuated muscle groups. Of the nine MR arteriograms performed at the level of the knee, eight were abnormal. The normal popliteal trifurcation was absent or in an abnormal location. We conclude that MR imaging of children with congenital lower extremity deformities shows many osteochondral and extraosseous abnormalities that are not depicted by conventional radiography. This information can help to plan early surgical intervention and prosthetic rehabilitation.

Child↗
PubMed1996

Pediatric musculoskeletal neoplasms. Evaluation with MR imaging.

MR imaging is an essential tool for the evaluation of musculoskeletal neoplasms in children. It provides useful information for diagnosis, determination of extent of disease, assessment of response to treatment, and detection of complications and effects of therapy. This article reviews the current role of MR imaging in each of these situations. A protocol for the evaluation of these lesions is suggested. Also addressed are issues related to differentiating pathologic conditions, normal marrow, and cartilaginous structures of the pediatric skeleton.

Bone Neoplasms↗
PubMed1995

Congenital absence of the portal vein: case report and MR demonstration.

Congenital absence of the portal vein (CAPV) is a rare anomaly that results from aberrant venous development in early embryonic life. The intestinal and splenic venous drainage bypasses the liver and drains directly into the inferior vena cava (IVC), the left renal vein, or the left hepatic vein. We describe a case where prenatal ultrasonography demonstrated an unusual C-shaped vessel between the umbilical vein and a dilated IVC, and failed to show a portal vein. Ultrasonography and magnetic resonance imaging and magnetic resonance angiography at 4 months of age again found no portal vein. The superior mesenteric vein drained into the left renal vein.

Abdomen↗
PubMed1995

Osteomyelitis and septic arthritis in children: appropriate use of imaging to guide treatment.

Modern imaging techniques have become essential components of the management of acute osteomyelitis and septic arthritis in children. This article addresses the role of these techniques, based on clinical practice guidelines recently developed at a children's hospital by an interdisciplinary group. The recommendations reflect a review of the literature and an analysis of our own experience with 84 children treated for musculoskeletal sepsis during the past 3 years. We attempt to optimize imaging resources by analyzing the unique aspects of these infections in the pediatric skeleton, the clinical needs at different stages of the disease, and the relative strengths and weaknesses of the various imaging procedures. Our goal was to define the use of imaging in cases of osteomyelitis and septic arthritis in children in specific clinical scenarios in which additional information is likely to lead to management modification.

Acute Disease↗
PubMed1994

Comparison between fast spin-echo and conventional spin-echo imaging of normal and abnormal musculoskeletal structures in children and young adults.

RATIONALE AND OBJECTIVES: The differences in imaging characteristics between conventional and fast spin-echo studies of the skeletons of children and young adults were evaluated. METHODS: Concurrent conventional and fast spin-echo studies of 23 patients were compared by measuring signal intensity, contrast, and, subjectively, conspicuity of normal and abnormal musculoskeletal structures. RESULTS: Fast proton-density-weighted images had lower signal-to-noise ratios of muscle, fat, and physeal, epiphyseal, and articular cartilage. Using more than three echoes for proton-density images resulted in blurring and decreased lesion conspicuity. On fast T2-weighted images, there was greater conspicuity of normal cortex, ligaments, and muscle; but less contrast between fat and water because of a higher signal-to-noise ratio of fat. When both sequences were obtained with similar image quality, fast spin-echo was 40% faster. CONCLUSION: Fast spin-echo studies allows faster imaging, but can have blurring on proton-density-weighted images and decreased fat-water contrast on T2-weighted images.

Adipose Tissue↗
PubMed1993

Indirect trauma to the growth plate: results of MR imaging after epiphyseal and metaphyseal injury in rabbits.

Abnormalities of the growth plate secondary to epiphyseal and metaphyseal injury were studied with magnetic resonance (MR) imaging, radiography, and histologic examination in 20 rabbits. Epiphyseal injury resulted in either the formation of a bony bridge across the growth plate or focal curving of the growth plate caused by a decrease in longitudinal growth. Metaphyseal injury resulted in interference with endochondral ossification, thickening of the growth plate, and extension of cartilage into the metaphysis. Serial MR images obtained during the first 6 weeks after injury showed persistence of abnormalities of the growth cartilage after epiphyseal injury, but resolution of abnormalities after metaphyseal injury. Abnormalities of the cartilage were best seen on T2-weighted images. Gadolinium enhancement showed reconstitution of metaphyseal vascularity after metaphyseal injury but did not enable detection of transphyseal vascularity after epiphyseal injury until a bony bridge formed.

Animals↗
PubMed1993

Metaphyseal abnormalities in children: pathophysiology and radiologic appearance.

The most active site of formation of bone in children is the metaphysis. Systemic and local diseases are reflected by alterations in the morphology of this region. In this pictorial essay, we examine several patterns of metaphyseal abnormalities seen on radiologic images and review the associated pathophysiology. Differential diagnosis may be aided by considering the pathologic mechanisms responsible for the various metaphyseal alterations.

Adolescent↗
PubMed1992

Scrotal ultrasonography in Henoch-Schönlein purpura.

The vasculitis of Henoch-Schönlein purpura may involve the scrotum and clinically mimic diseases requiring surgical intervention, such as testicular torsion or an incarcerated inguinal hernia. The ultrasonographic features include marked edema of the scrotal skin and contents with intact vascular flow in the testicles. These findings may suggest the correct diagnosis and prevent unnecessary surgical exploration.

Child, Preschool↗
PubMed1991

Epiphyseal marrow in infancy: MR imaging.

Hypointense epiphyseal marrow on T1-weighted magnetic resonance images often suggests disease. To determine whether hypointense marrow sometimes represents normal red marrow in a recently ossified epiphyseal center, the authors studied 38 infants without known marrow disease. Patients with hypointense epiphyseal marrow on T1-weighted images were younger (3.9 months +/- 3.2) than those with hyperintense marrow (9.6 months +/- 3.9) (P less than .001). T1-weighted imaging and histologic correlation were also performed in animals. The signal was hypointense and the marrow was red in the epiphyseal centers of all newborn animals, while all 6-week-old animals had hyperintense signal and yellow marrow. The authors conclude that hypointense marrow on T1-weighted images represents normal red marrow in a recently formed ossification center in newborn rabbits and lambs, and the same is probably true in humans. Epiphyseal marrow becomes hyperintense within a few months of development of the secondary center of ossification.

Animals↗
PubMed1989

Pulmonary hypertension.

Conventional radiography reflects the underlying cause of pulmonary hypertension and may help to distinguish between precapillary and postcapillary etiologies. Adjunctive nuclear medicine studies may aid in identifying chronic pulmonary emboli as a cause of precapillary hypertension.

Chronic Disease↗
PubMedDate not supplied

Limited magnetic resonance imaging examination after surgical reduction of developmental dysplasia of the hip.

We evaluated the utility of limited magnetic resonance imaging (MRI) after surgical reduction and spica casting for developmental dysplasia of the hip (DDH) with respect to feasibility, time, need for sedation, and charge. Eighteen limited MRI examinations were performed in 10 children (mean age, 9 months) with a 1.5-T magnet. Twenty-eight dysplastic hips were imaged within 4 hours of surgery. Mean imaging time for two sequences was approximately 3 minutes. All examinations were interpretable, although three were degraded by motion. No child required sedation, additional sequences, or repeat study. Two thirds of the dysplastic hips had no proximal femoral ossification center on MRI. A reduced charge was assigned to the examination. We conclude that using limited MRI to confirm intraoperative reduction for DDH is feasible and desirable. The lack of radiation or need for sedation, the reduced charge that reflects the short time needed for imaging, and the superb visualization of nonosseous structures have made it our preferred method to evaluate surgical reduction of DDH.

Age Factors↗