Biomedical subjects

Liat Ben Sira

Publications and source records attributed to Liat Ben Sira.

6 recordsLinked to original sources

PubMed2006

Evidence of a developmental cerebello-cerebral disorder.

The objective of this study was to examine the cognitive and neuroanatomical features of an adolescent with developmental hypoplastic left cerebellum who presented with executive and visuo-spatial deficits, nonverbal learning disabilities and interpersonal difficulties. He underwent a neuropsychological assessment, MRI and diffusion tensor imaging MRI. The neuropsychological impairments were primarily in executive functions, spatial and visual perception, graphomotor skills, arithmetic, social perception and comprehension. Fractional anisotropy, which is measured by diffusion tensor imaging and enables assessment of axonal integrity, was reduced in the right cerebral peduncle and right hemisphere white matter (p < 0.001). Based on the results, we hypothesize that disruption of neural circuits linking the hypoplastic left cerebellum to the right hemisphere may contribute to the evolution of a neurocognitive syndrome with characteristics of the developmental right hemisphere syndrome and suggestive of the cerebellar cognitive-affective syndrome.

Adolescent↗

PubMed2005

Normal white matter development from infancy to adulthood: comparing diffusion tensor and high b value diffusion weighted MR images.

PURPOSE: To evaluate the sensitivity of high b value diffusion weight magnetic resonance imaging (DWI) in detecting normal white matter maturation, compare it to conventional diffusion tensor imaging (DTI), and to obtain normative quantitative data using this method. MATERIALS AND METHODS: High b value DWI (b(max) = 6000 sec/mm(2)) using q-space analysis and conventional DTI (b = 1000 sec/mm(2)) were performed on 36 healthy subjects aged 4 months to 23 years. Fractional-anisotropy (FA), apparent-displacement, and apparent-probability values were measured in all slices and in six regions of interest (ROIs) of large fiber tracks. Values were correlated with each other and with age using regression analysis. RESULTS: FA, displacement, and probability indices from all slices were highly correlated with each other (r > 0.87, P < 0.0001) and with age (r > 0.82, P < 0.0001). All age-related changes in the six pre-determined ROIs were best fitted by mono-exponential functions. Changes in the splenium extended to a later age when compared with the genu of the corpus-callosum, while the centrum semi-ovale demonstrated the latest changes with age. CONCLUSIONS: High b-value DWI and DTI showed changes in white matter from infancy through adulthood. However, high b-value detects a signal that is likely to originate mainly from the intra-axonal water population, and thus may represent different aspects of development and different sensitivity to pathology.

Adolescent↗

PubMed2005

Predominantly upper limb weakness, enlarged cisterna magna, and borderline intelligence in a child with de novo mutation of the skeletal muscle alpha-actin gene.

We present a 10-year-old boy from nonconsanguineous parents of Libyan (Sephardi) Jewish origin. Mild dysmorphism, hypotonia, and clubfoot deformities were noted at birth. On follow-up, he had borderline intelligence and nonprogressive muscle weakness, predominantly in the upper extremities. Physical examination revealed mild facial weakness, a bell-shaped chest cavity, kyphosis, winging of the scapula, and hypotonia of the shoulder girdle. Muscle biopsy demonstrated prominent variation in fiber size and central nuclei and numerous subsarcolemmal particles on modified Gomori trichrome stains. Electron microscopy depicted areas of disrupted sarcomeres with abnormal aggregates. Brain magnetic resonance imaging showed mild widening of the lateral ventricles and an enlarged cisterna magna. Molecular DNA analysis by polymerase chain reaction (PCR) and direct sequencing revealed a de novo heterozygous missense mutation in the skeletal muscle alpha-actin gene (ACTA1) changing codon 348 from TCG serine to TTG leucine.

Actins↗

PubMed2003

Mass at the splenic hilum: a clue to torsion of a wandering spleen located in a normal left upper quadrant position.

Wandering spleen is an extremely rare condition in which the spleen is lacking its normal ligamentous attachments and therefore can move to an ectopic position in the abdomen or pelvis. Wandering spleen predisposes the patient to life-threatening complications due to torsion of the spleen's vascular pedicle, with resulting splenic infarction, portal hypertension, and bleeding. Because of the nonspecific symptoms, imaging plays an important role. To our knowledge, only a few case reports describing wandering spleen in the pediatric population have been published, including 2 cases in infancy. We report a case of splenic torsion in an infant with a preoperative diagnosis made on the basis of color and power Doppler sonography. The diagnosis was confirmed by contrast-enhanced helical computed tomography (CT) and proved at surgery. On sonography, a diffusely hypoechoic spleen and a mass at the splenic hilum representing the torsed splenic pedicle were shown. The splenic hilar mass correlates with the CT "whirl" sign indicative of torsion.

Choristoma↗

PubMed2003

Fetal cytomegalovirus infection of the brain: the spectrum of sonographic findings.

BACKGROUND AND PURPOSE: Congenital cytomegalovirus (CMV) infection can cause a wide range of brain anomalies. These changes have been well described postnatally, but descriptions of their in utero evolution are scarce. The purpose of this study was to analyze the sonographic spectrum of intracranial abnormalities in fetuses with proved CMV infection and to determine characteristic patterns of this infection. METHODS: We reviewed the transabdominal and transvaginal sonograms of eight fetuses with proved CMV infection. The sonographic analysis searched for signs of ventriculitis, leukomalacia, calcification, vasculitis, and periventricular cyst formation. The gyral pattern, corpus callosum, and cerebellar morphology also were examined. Fetal MR imaging was performed in two cases. RESULTS: The sonographic diagnosis of suspected CMV infection was made at a mean gestational age of 27.5 weeks (range, 22-37 weeks). An abnormal pattern of periventricular echogenicity was found in all fetuses. Echogenic intraparenchymal foci and ventriculomegaly were present in five fetuses. Other signs of fetal infection were intraventricular adhesions, periventricular pseudocysts, sulcation and gyral abnormal patterns, hypoplastic corpus callosum, cerebellar and cisterna magna abnormalities, and signs of striatal artery vasculopathy. For all fetuses, transvaginal sonography provided additional information. Fetal MR imaging provided additional information in one case. CONCLUSION: The presence of the described sonographic findings, particularly if two or more are present in the same fetus, is an indication for CMV investigation.

Brain↗

PubMedDate not supplied

Role of 18F-FDG PET/CT in staging and follow-up of lymphoma in pediatric and young adult patients.

OBJECTIVE: To assess the role of 18F-Fluorodeoxyglucose (18F-FDG) PET/CT in pediatric patients with Hodgkin disease (HD) and non-Hodgkin lymphoma (NHL). MATERIALS AND METHODS: 31 patients, mean age 12.9 +/- 5.1, HD (n = 24), and NHL (n = 7) underwent 18F-FDG PET/CT at diagnosis (n = 31 studies) and later in the course of the disease (n = 75 studies). The findings of PET/CT were correlated with diagnostic CT and clinical follow-up. RESULTS: PET/CT findings resulted in a change of disease staging in 10 patients (32.3%), upstaging in 7 (22.6%) and downstaging in 3 (9.6%). On a lesion analysis, 164 disease sites were detected by PET/CT of which 38 were overlooked by DCT. At mid-treatment, PET was negative in 28 out of 31 patients (90%) with negative predictive value of 96% as all latter patients except for 1, were disease free (mean 15.4 +/- 8.8 months). The positive predictive value of persistent increased 18F-FDG uptake was 100% as 3 patients with latter findings had active disease. On the CT part, 76 residual masses were identified in 22 patients. Increased 18F-FDG uptake was detected in 11 masses in 4 patients who had active disease. Remaining 65 PET negative masses were false positive findings. The positive predictive value of residual CT mass was 14%. CONCLUSIONS: PET/CT is associated with change in staging in approximately 1 out of 3 pediatric patients with HD and NHL. When used for monitoring response to treatment, a negative study is associated with disease-free period, even when residual mass is detected. A positive PET study indicates residual malignant disease.

Adolescent↗