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T Laor

Publications and source records attributed to T Laor.

At least 19 recordsLinked to original sources
PubMed2001

Knee in early juvenile rheumatoid arthritis: MR imaging findings.

PURPOSE: To determine the magnetic resonance (MR) imaging findings in the knee in early juvenile rheumatoid arthritis. MATERIALS AND METHODS: MR imaging (1.5 T) was performed in the more symptomatic knee in 30 children with juvenile rheumatoid arthritis with a symptom duration 1 year or less. Conventional, fast spin-echo, three-dimensional gradient-echo, and gadolinium-enhanced T1-weighted images were assessed. Two radiologists independently read the images, and a third resolved disagreements. These images were compared with knee radiographs in 27 children. RESULTS: Mean maximal synovial thickness was 4.8 mm +/- 2.4 (SD). Mean synovial volume was 15.4 mL +/- 10.8. Suprapatellar joint effusions were seen in 26 (87%) of 30 knees, meniscal hypoplasia in 11 (37%) of 30 knees, and abnormal epiphyseal marrow in eight (27%) of 30 knees. Three knees had articular cartilage contour irregularity, fissures, and/or thinning. One knee had a bone erosion. Knee radiographs showed suprapatellar fullness in 78% of the knees, joint space narrowing in one knee, and no bone abnormalities. CONCLUSION: Synovial hypertrophy and joint effusions are the most frequent MR imaging findings of knees in early juvenile rheumatoid arthritis. Early in the disease, radiographically occult cartilage and bone erosions are uncommonly seen at MR imaging. The potential relationship of synovitis to cartilage abnormalities deserves further study.

Adolescent↗
PubMed2000

Severe scrotal pain in boys with Henoch-Schönlein purpura: incidence and sonography.

BACKGROUND: Henoch-Schönlein purpura (HSP) is a systemic vasculitis with multiorgan involvement. The scrotal involvement and its sonographic appearance are less well recognized than that of the kidneys and abdomen, and the reported incidence is varied. OBJECTIVE: To review the incidence of significant scrotal involvement in boys with HSP and its sonographic characteristics. MATERIALS AND METHODS: Thirteen boys (ages 4-11 years) out of 87 boys diagnosed with HSP, over a 15-year period had significant scrotal complaints. Seven underwent sonographic evaluation to define the extent of scrotal involvement and because testicular torsion was being considered. RESULTS: Scrotal involvement producing significant pain occurred in 15 % of boys with HSP. The majority of boys had the diagnosis of HSP established before developing scrotal complaints. Sonographic findings consistently included an enlarged, rounded epididymis, thickened scrotal skin, and a hydrocele. The testes themselves were usually sonographically normal. CONCLUSIONS: Scrotal involvement in boys with HSP is not uncommon. The sonographic findings in the scrotum are sufficiently characteristic to allow distinction from torsion in most cases.

Child↗
PubMed2000

Accuracy of MR imaging for detecting epiphyseal extension of osteosarcoma.

BACKGROUND: Too few patients are receiving epiphyseal-sparing limb salvage procedures for osteosarcoma. OBJECTIVE: To determine how magnetic resonance (MR) imaging can best predict the epiphyseal extension of osteosarcoma. MATERIALS AND METHODS: Forty children underwent complete pretreatment static and dynamic contrast-enhanced MR imaging (DEMRI). Static MR images [T1-weighted and short tau inversion recovery (STIR)] of the epiphyses were read in three ways: (1) for suspicion of any abnormality (tumor or edema), (2) for suspicion of tumor, excluding suspected edema, and (3) validating the second method by using a scale to rate the likelihood of tumor. Presentation imaging was compared to histopathologic findings after chemotherapy and resection. The receiver operating characteristic (ROC) method was used to analyze the scaled ratings of static MR and DEMRI values. RESULTS: At delayed resection, 20 of 40 children with osteosarcoma had confirmed epiphyseal tumor; however, 32 epiphyses were abnormal on STIR and 28 abnormal on T1. Differentiating suspected tumor from edema increased the accuracy to an Az (area under the ROC curve) of 0.94 for both T1-weighted and STIR static sequences. T1-weighted MR had better specificity and STIR better sensitivity at any given rating. DEMRI was slightly less accurate (Az = 0.90). CONCLUSION: Static MR imaging most accurately detected epiphyseal extension of osteosarcoma when readers distinguished suspected tumor from edematous or normal tissue.

Adolescent↗
PubMed2000

Normal maturation of the distal femoral epiphyseal cartilage: age-related changes at MR imaging.

PURPOSE: To determine how signal intensity in the cartilaginous distal part of the femoral epiphysis varies with (a) age, (b) sex, and (c) distribution to the medial or lateral condyle on magnetic resonance (MR) images. MATERIALS AND METHODS: Sixty-six sagittal T2-weighted or inversion-recovery MR images of the distal femoral epiphysis in children aged 2 months to 5 years 5 months were evaluated. Epiphyses were categorized into five types on the basis of progressive signal intensity changes within the epiphyseal cartilage along the weight-bearing region and posterior condyles. Epiphyseal type was compared with age, sex, and distribution of signal intensity changes within the condyle. RESULTS: In early infancy, epiphyseal cartilage was homogeneous. During the 2nd year, signal intensity along the weight-bearing region decreased. With further advancing age, signal intensity in the posterior femoral condyles increased and became progressively more focal. The increase in epiphyseal grade correlated with age for both the medial and the lateral femoral condyles (r = 0.71 and r = 0.77, respectively; P < .001). There was no significant difference in epiphyseal changes between boys and girls or between medial and lateral condyles. CONCLUSION: There is normal age-related variation in MR imaging signal intensity within the cartilaginous epiphysis of the distal femur. This may be related to weight bearing and epiphyseal maturation and should not be confused with disease.

Bone Development↗
PubMed1999

Nonradiopaque penetrating foreign body: "a sticky situation".

Foreign bodies within soft tissues are common in children. They may cause a chronic inflammatory reaction that can result in abnormal findings on radiographs, including lytic or blastic osseous changes. These radiographic findings can mimic both benign and malignant processes. In cases where the history is uncertain and the foreign body is not recognized, magnetic resonance (MR) imaging can make a specific diagnosis and direct appropriate therapy.

Child↗
PubMed1999

Subcutaneous granuloma annulare: MR imaging features in six children and literature review.

PURPOSE: To describe the magnetic resonance (MR) imaging findings of subcutaneous granuloma annulare (SGA), a rare mass of early childhood. MATERIALS AND METHODS: MR imaging studies and clinical records in six children aged 2 1/2-4 years in whom SGA was diagnosed between 1993 and 1997 were retrospectively reviewed. All MR imaging examinations included T1-weighted and fast spin-echo T2-weighted sequences. Three children received intravenous contrast material. The diagnosis was established by using excisional biopsy results, with confirmation by means of characteristic features in mucin-stained specimens. RESULTS: All children presented with a nontender, nonmobile mass. The lesion in all six children was confined to the pretibial (n = 5) or prepatellar (n = 1) soft tissues. MR imaging characteristics were uniform. Masses were subcutaneous in location and had ill-defined margins. On T1-weighted images, the lesion was isointense or slightly hyperintense to muscle. On T2-weighted images, the signal intensity was more heterogeneous, but the lesion was predominantly hyperintense. In three children who received contrast material, the lesion enhanced nearly homogeneously. CONCLUSION: Although SGA can often be diagnosed on the basis of clinical characteristics, MR imaging may be requested by practitioners unfamiliar with the lesion. In these cases, with recognition of typical MR imaging features, a limited biopsy and specific histologic preparation that includes mucin staining can be recommended.

Biopsy↗
PubMed1998

Diagnostic imaging in the evaluation of vascular birthmarks.

This article reviews the role of modern diagnostic imaging in the evaluation of patients with vascular birthmarks. There are two main categories of vascular anomalies: hemangiomas and vascular malformations. The findings on plain radiography, sonography, computed tomography (CT), magnetic resonance imaging (MRI) and angiography, and the appropriate sequence of investigation for the different vascular anomalies are discussed.

Adolescent↗
PubMed1998

MR cholangiography in children after liver transplantation from living related donors.

OBJECTIVE: The purpose of this study is to report our technique for MR cholangiography in children and to describe the postoperative imaging findings in children who have undergone liver transplantation from living related donors. CONCLUSION: MR cholangiography can be used to delineate anatomy and morphology of the bile ducts of the left lateral segment graft in children who have undergone liver transplantation from living related donors. This information can guide treatment of postoperative biliary complications with interventional radiology or surgery.

Adolescent↗
PubMed1998

Gadolinium-enhanced MR imaging of pediatric patients after reduction of dysplastic hips: assessment of femoral head position, factors impeding reduction, and femoral head ischemia.

OBJECTIVE: We describe gadolinium-enhanced MR imaging of position and vascular enhancement of the femoral head in pediatric patients who have undergone reduction of hip dislocation. SUBJECTS AND METHODS: Within 24 hr of hip reduction and spica casting, we performed 25 gadolinium-enhanced MR studies in 18 infants and young children (15 girls, three boys) with 23 dysplastic hips. All but two patients underwent closed reductions. We evaluated intraoperative arthrograms for obstacles to reduction and subsequent radiographs for avascular necrosis. RESULTS: MR images showed that all femoral heads were in their respective acetabula, but several structures interfered with concentric reduction. Obstacles to reduction included a pulvinar (n = 16), infolding of the capsule (n = 9), interposition of the labrum (n = 2), and a hypertrophied ligamentum teres and transverse ligament (n = 2). All 50 femoral heads showed enhancement: 35 normally, 10 homogeneously but less than on the contralateral femoral head or the ipsilateral greater trochanter, and five with areas of focally decreased enhancement. Hips that showed decreased enhancement had undergone greater degrees of abduction (r = .38, p < .01). CONCLUSION: Gadolinium-enhanced MR imaging can reveal abnormalities of hip position and proximal femoral epiphyseal and physeal vascularity that can occur after hip reduction. Abnormalities of enhancement were more frequent in patients who had greater femoral abduction. The effect of decreased epiphyseal vascular enhancement is still uncertain.

Arthrography↗
PubMed1998

MR lymphangiography in infants, children, and young adults.

OBJECTIVE: Our objective was to offer a preliminary description of MR lymphangiography; its uses and limitations; and its findings in infants, children, and young adults. SUBJECTS AND METHODS: Twenty-nine patients underwent 32 MR lymphangiographic examinations for evaluation of vascular malformations, other masses, soft-tissue swelling, gigantism, fluid accumulation, or pain. MR lymphangiography was based on a heavily T2-weighted fast spin-echo sequence and a maximum-intensity-projection algorithm. We assessed the axial and off-axial lymphatic channels in conjunction with MR venography to help differentiate veins from lymphatics. Correlation was made with published lymphangiograms and anatomic diagrams to assist interpretation and (when available) with histologic specimens (n = 11) for validation. RESULTS: Presumed lymphatic channels were seen universally, although 14 examinations showed incomplete venous signal suppression. Lymphatic channels appeared normal in eight children and in 20 of the 21 asymptomatic contralateral limbs. Ten patients had an increased number and size of off-axial channels, including seven children with large, diffuse low-flow vascular malformations. Enlarged axial and off-axial channels were seen in five patients, four of whom had Klippel-Trénaunay syndrome. Six patients, each with an extensive hemangioendothelioma, Klippel-Trénaunay syndrome, Gorham syndrome, or unilateral body edema, showed absence or interruption of axial channels. CONCLUSION: MR lymphangiography appears to be a useful noninvasive technique to study superficial and deep lymphatic channels in children with local or diffuse vascular lesions or swelling of extremities. Its limitations notwithstanding, the technique may offer further insight into the nature of vascular anomalies, may direct therapy, and may predict prognosis.

Adolescent↗
PubMed1998

Congenital anomalies and vascular birthmarks of the lower extremities.

MR imaging is an invaluable tool for the evaluation of congenital abnormalities and vascular birthmarks of the extremities in children. These abnormalities of the immature musculoskeletal system are often underestimated by radiography. MR imaging is useful for diagnosis, assisting in therapy, showing response to treatment, and determining prognosis. Localized and generalized abnormalities of the lower extremities and issues pertinent to their MR imaging are illustrated in this article.

Adolescent↗
PubMed1997

Local physeal widening on MR imaging: an incidental finding suggesting prior metaphyseal insult.

OBJECTIVE: To offer a descriptive review which characterizes and evaluates the significance of local physeal widening, (cartilaginous signal extending from the physis into the adjacent metaphysis), identified on magnetic resonance (MR) imaging. MATERIALS AND METHODS: MR images (recollected from exams performed between 1988 and 1995) of 31 metaphyses in 22 children where we recognized local physeal widening were examined retrospectively. These areas of physeal widening were evaluated for morphology, depth, location, signal intensity, and the coexistence of epiphyseal alterations. The characteristics of the signal abnormalities were correlated with the duration and type of any identifiable insult to the adjacent metaphysis, and with the development of growth disturbance. RESULTS: Twenty-six metaphyses had identifiable insults (19 single event and 7 sustained or repetitive). The widened physes were of focal tongue (n = 15), broad band (n = 10), or mixed (n = 6) morphology. Most (n = 27) areas of widening were isointense with the physeal cartilage on all sequences. Subsequent growth disturbance was more likely when the metaphyseal insult was a single event rather than sustained or repetitive (P = 0.023), with focal tongues (P = 0.029), and with centrally located lesions (P = 0.030). In five cases, the adjacent epiphysis showed signal abnormalities; all developed growth disturbance. Histologic examinations available in two limbs confirmed that the MR findings represented extensions of hypertrophic physeal chondrocytes into the metaphysis. CONCLUSION: Incidentally observed local physeal widening in a growing bone may represent the imprint of a previous or ongoing interference with endochondral ossification from a prior metaphyseal insult, rather than a primary metaphyseal disorder. Single event insults, physeal widening of focal tongue morphology, central distribution in the metaphysis, and concomitant epiphyseal signal abnormalities on MR imaging are significant predictors of subsequent growth disturbance.

Adolescent↗
PubMed1997

Methotrexate osteopathy in patients with osteosarcoma.

PURPOSE: To determine the frequency of osteopathy in patients treated with high-dose, short-term, intravenous methotrexate for osteosarcoma and whether this complication varies with patient age and methotrexate dose. MATERIALS AND METHODS: Radiographs and available scintigrams of 87 patients with osteosarcoma who received high-dose methotrexate were reviewed retrospectively for severe osteopenia, dense zones of provisional calcification, insufficiency fractures, and involvement of multiple bones. At least three of these radiographic abnormalities were required for the diagnosis of osteopathy. Patients with bone metastases were excluded. RESULTS: Eight patients (cumulative dose, 60-144 g/m2) exhibited adverse skeletal findings similar to those described in children with leukemia who received low-dose maintenance methotrexate. Images showed severe osteopenia (n = 8), dense zones of provisional calcification (n = 8), multiple bone involvement (n = 6), and insufficiency fractures (n = 6). Most commonly affected sites were the distal tibia (n = 7), distal radius and proximal humerus (n = 3), and calcaneus and public ramus (n = 2). The affected patients were significantly younger (mean age, 9.2 years; P < .001) than the 79 unaffected patients (mean age, 14.9 years). CONCLUSION: Osteopathy occurs in approximately 9% of children who receive high-dose methotrexate for osteosarcoma and is substantially more likely to occur in younger patients. The complication rate was not directly dose dependent.

Adolescent↗
PubMed1997

Normal gadolinium-enhanced MR images of the developing appendicular skeleton: Part 2. Epiphyseal and metaphyseal marrow.

OBJECTIVE: We have studied how gadolinium enhancement of T1-weighted MR images affects the expected normal differences in signal intensity between metaphyseal hematopoietic and epiphyseal fatty marrow. We have also analyzed how enhancement affects the expected normal changes in the MR images of the marrow due to fatty conversion. MATERIALS AND METHODS: We analyzed gadolinium-enhanced MR images of normal distal femurs in 18 immature rabbits that were 5-11 weeks old and of normal proximal femurs in 18 infants, children, and young adults who were 2 months to 21 years old. In all subjects, we studied the change with age in signal intensity and enhancement ratio of the epiphyseal and metaphyseal marrow. In the rabbits, marrow composition and transformation were histologically verified. RESULTS: On unenhanced T1-weighted MR images of the rabbits and of the infants, children, and young adults, epiphyseal signal intensity always exceeded metaphyseal signal intensity; however, the enhancement ratio was always greater in the metaphysis. The signal intensity in metaphyseal and epiphyseal marrow on unenhanced MR images increased with age. However, enhancement ratios decreased with age in both areas. In the rabbits, histologic studies showed more fatty marrow in the epiphysis than in the corresponding metaphysis and an age-related increase in marrow fat at both sites. CONCLUSION: In the marrow of the extremities, gadolinium enhancement is greater in the (hematopoietic) metaphysis than in the (fatty) epiphysis. In both areas, enhancement decreases as the marrow becomes more fatty. On T1-weighted images, administration of a gadolinium-containing contrast agent reduces the normal contrast between hematopoietic and fatty marrow and obscures the changes in marrow signal intensity due to fatty conversion.

Adolescent↗
PubMed1996

Musculoskeletal magnetic resonance imaging: how we do it.

This paper reviews the techniques that we employ to perform musculoskeletal magnetic resonance imaging in the pediatric patient. We examine the procedures for preparation and screening of the patient and the protocols for sedation. The selection of imaging coils and sequences for the evaluation of the pediatric musculoskeletal system is also addressed, followed by a summary of scanning protocols.

Bone Diseases↗
PubMed1996

Magnetic resonance venography of congenital vascular malformations of the extremities.

Contrast angiography can demonstrate the vascular components of a vascular malformation, but can be technically challenging in small patients with complex venous anomalies. We reviewed the role of magnetic resonance venography (MRV) in the evaluation of children with predominantly low-flow, vascular malformations of the extremities. MRV (2D time-of-flight technique) and magnetic resonance (MR) imaging examinations were performed in ten young patients with congenital predominantly low-flow vascular malformations of the extremities. MR imaging was used to characterize and determine the extent of the malformations, and MRV to evaluate the deep and superficial venous channels. In all patients, MRV studies were reviewed in conjunction with contrast angiograms, considered the gold standard, to confirm the findings. All significant channel anomalies seen with contrast angiography were identified with MRV. In addition, MRV demonstrated some veins that were not intentionally opacified during contrast studies. MRV demonstrates both the superficial and deep conducting veins, whereas contrast angiography is a more directed study, evaluating only those channels intentionally opacified. Together, MR imaging and MRV data can non-invasively form the basis for determining the prognosis and choosing the individual treatment of congenital vascular malformations of the extremities.

Adolescent↗