Biomedical subjects

V Engelbrecht

Publications and source records attributed to V Engelbrecht.

At least 37 records · Page 2Linked to original sources

PubMed2001

MR imaging of bone marrow in glycogen storage disease type IB in children and young adults.

OBJECTIVE: Patients with glycogen storage disease type IB have neutropenia and neutrophil dysfunction that predispose them to frequent infections, for which they are given granulocyte colony--stimulating factor. Because neutropenia is a consequence of defects in myeloid maturation, the bone marrow aspirations show hypercellularity due to myeloid hyperplasia. This study evaluated MR imaging of bone marrow in glycogen storage disease type IB with and without granulocyte colony-stimulating factor. CONCLUSION: As confirmed by the histologic results in bone marrow aspirations, abnormal findings on MR images of bone marrow in patients with glycogen storage disease type IB indicate an increased myelopoietic activity, which is augmented by treatment with granulocyte colony-stimulating factor.

Adolescent↗

PubMed2001

Global estimation of myelination in the developing brain on the basis of magnetization transfer imaging: a preliminary study.

BACKGROUND AND PURPOSE: In the developing brain, myelination occurs in an orderly and predetermined sequence. The aim of this study was to determine whether such changes can be tracked using volumetric magnetization transfer imaging. METHODS: Three-dimensional magnetization transfer imaging was performed in 50 children (age range, 0.6-190 months) with no evidence of developmental delay or structural abnormalities. Volumetric magnetization transfer ratio (MTR) parameters generated of the whole brain were mean MTR and height and location of the MTR histogram peak. Relationships between volumetric MTR parameters and age were assessed using nonlinear regression analysis. RESULTS: With age, all volumetric MTR parameters changed exponentially in a way that was best expressed by the function y = a + b.exp(-x/c) (P < .0001). The peak height of the MTR histogram was the parameter that changed most predictably and that continued to change for the longest period of time. CONCLUSION: With this preliminary study, we show that by using volumetric MTR analysis, it is possible to monitor changes in the developing brain, presumably the myelination progress. This method has a potential role for detecting myelination disorders in the pediatric population, for studying the natural history of these diseases, and for monitoring the effects of treatment.

Adolescent↗

PubMed2000

Neurocutaneous melanosis with hydrocephalus, intraspinal arachnoid collections and syringomyelia: case report and literature review.

Neurocutaneous melanosis (NCM) is a rare nonfamilial syndrome, characterised by large or numerous congenital pigmented nevi and excessive proliferation of melanin-containing cells in the leptomeninges. We report the MR findings in the brain and spine of a child with NCM who underwent neurosurgical treatment and was followed up for 8 years. The findings in this child (small hyperintense collections of melanocytes in both temporal lobes, mild meningeal enhancement along the spine and the development of an extensive subarachnoid CSF accumulation with cord compression and syringomyelia) are believed to be exceptionally rare.

Arachnoid↗

PubMed2000

[MRI of aseptic osteonecrosis in children and adolescents with acute lymphoblastic leukemia].

PURPOSE: To evaluate the incidence, localisation, and course of symptomatic aseptic osteonecrosis (AON) in children undergoing treatment for acute lymphoblastic leukemia (ALL). METHODS: 72 MRI examinations obtained from 26 children with bone pain selected from a group of 121 children with ALL were evaluated retrospectively. The area of the AON was determined by computer assisted planimetry. Follow-up examinations after 2-5 years were considered. RESULTS: 10/121 (8.3%) of the children had symptomatic AON, the number of lesions varied between 1 and 24 per child. 62/66 lesions were localized within the lower extremities. 58% of the AON were positioned in the epiphysis and 42% in the meta- and diaphysis. The mean area of AON was 7.6 cm2 with a range of 0.5 to 50 cm2. Follow-up examinations revealed a regression in 19 AON, no change in 43 and a progression in 4 lesions. AON within the epiphysis with joint involvement or lesions greater than 9 cm2 more frequently showed a progression of AON with final joint destruction. An elevated risk for AON was seen in children older than 10 years and in children with intensified chemotherapy due to high-risk ALL. CONCLUSION: AON is a common complication in ALL-children under chemotherapy. Most frequently, the course is benign but large AON with joint involvement have an elevated risk for progression of AON with final joint destruction.

Adolescent↗

PubMed2000

[Ganglioneuromas in childhood: CT and MRI characteristics].

PURPOSE: The aim of this study was to demonstrate the typical appearance of ganglioneuromas in computer-assisted tomography (CT), and magnetic resonance imaging (MRI). MATERIAL AND METHODS: Retrospective analysis of diagnostic imaging (9 CT, 6 MRI) in 9 children aged 3 to 15 years with the histological diagnosis of ganglioneuroma. RESULTS: The tomographies showed large (max. 13.4 cm in diameter) round or oval tumors with sharp delineation. The sites of the tumors were the retroperitoneum (5), the mediastinum (3), and the adrenal gland (1). Intraspinal tumor involvement occurred in 4 cases. On comparing CT with MRI, MRI was more accurate in defining the intraspinal involvement. The ganglioneuromas were of hypodense appearance in the native CT scan and showed moderate enhancement upon administration of contrast media. In five patients tumor calcifications with a disseminated sprinkled pattern were seen in CT. In MRI T1-weighted scans the tumors were homogeneous and hypointense, after gadolinium application a marked enhancement was evident. In T2-weighted scans the tumors were hyperintense. CONCLUSION: At the time of diagnosis ganglioneuromas are generally large tumors which can be well detected by CT and MRI. Information towards the diagnosis is given by the appearance of the ganglioneuromas in CT and MRI. However, MRI is the modality of choice due to its superiority in documenting intraspinal tumor expansion.

Adolescent↗

PubMed2000

MRI evaluation of aseptic osteonecrosis in children over the course of hyperbaric oxygen therapy.

PURPOSE: The study aimed at MRI evaluation of aseptic osteonecrosis (AON) in children over the course of hyperbaric oxygen (HBO) therapy. MATERIAL AND METHODS: Retrospective analysis of 72 MRI studies in 20 children presenting with AON during chemotherapy. Two groups were differentiated: Gr. I (n = 8) was treated exclusively with relief of weightbearing structures, Gr. II (n = 12) was additionally treated with HBO therapy. The MRI examinations were evaluated by a point-score system (1-6 points) by two radiologists. RESULTS: Gr. II initially showed more severe findings (average score: 3.4) in comparison to Gr. I (average score: 2.65). During the follow-up time period the average scores rose to 3.2 score-points in Gr. I and 4.1 points in Gr. II. No statistically significant difference was evident between the two groups in the course of AON. CONCLUSION: The majority of chemotherapy associated AON which initially present with advanced findings show a progression in MRI over their further course. HBO therapy in addition to the relief of affected weightbearing structures statistically shows no significant improvement in MRI morphology during the course of the treatment.

Antineoplastic Agents↗

PubMed2000

Multiple intracranial juvenile xanthogranulomas. Case report.

The authors report on an 11-year-old boy in whom proptosis of the eye caused by a benign intraosseous xanthofibroma of the left orbital wall became clinically apparent at the age of 4 years. Two years later he developed bilateral papilledema, at which time computerized tomography and magnetic resonance studies revealed multiple enhancing intracranial lesions. The largest mass was located in the left middle fossa; other lesions were located at the tentorium cerebelli, in both lateral ventricles, near the superior sagittal sinus, and extracranially near the left jugular vein. The mass in the left middle fossa was resected and diagnosed as juvenile xanthogranuloma (JXG). Thirty months later, the patient again became symptomatic, exhibiting behavioral abnormalities and a decrease in mental powers. At that time, the two remaining lesions in both lateral ventricles had grown enough to cause trapping of the temporal horns and raised intracranial pressure. These lesions were successively resected and histopathologically confirmed to be JXGs. However, resection of the second intraventricular lesion was complicated by postoperative bilateral amaurosis, presumably caused by postdecompression optic neuropathy. According to a review of the literature, fewer than 20 patients with JXG involving the central nervous system have been reported. The patient described in this report is the first in whom multiple intracranial JXGs developed in the absence of cutaneous manifestations. Although JXGs are biologically benign lesions, the treatment of patients with multifocal and/or progressive intracranial manifestations is problematic.

Brain Diseases↗

PubMed1999

Measuring in vivo myelination of human white matter fiber tracts with magnetization transfer MR.

Precise characterization of white matter pathways is important for the understanding of structural-functional relationships in the human brain. While it is known from postmortem studies that the connectivity of cortical areas is conveyed by projection, commissural, and association fibers, most clinical studies disregard useful information about specific fiber tracts. Magnetization transfer (MT) MR detects the relative proportion of free mobile protons and immobile protons bound to macromolecules. MT values correlate with histopathology and it has been proposed that in the white matter, the amount of magnetization transfer correlates with the degree of myelination. Thus, MT-MR provides measures that may reflect more accurately the physiology and natural course of diseases involving the white matter. We applied this quantitative in vivo method to five children at different ages to determine whether the maturational changes of distinct fiber tracts could be measured. All regions of interest were localized by means of Brodmann's original descriptions and the additional use of reconstructed 3D-matched data from 10 myelin-stained human brain specimens. With this atlas-guided approach we localized and measured 26 supratentorial white matter fiber tracts in each hemisphere, connecting to primary as well as association cortices. All fiber tracts showed consistent age-related MT changes and the strongest effects were found in those tracts projecting to the primary cortical areas. These results suggest that our method is suitable for in vivo MT measurements in specific fiber tracts. It can provide data that relate to myelination during ontogenesis or myelination delays in myelin disorders. In the clinical domain, the focus on specific fiber tracts appears to be advantageous over standard approaches, because such system of parcellation is based on the functional anatomy of the white matter. Consequently, it may be especially useful for topical analysis in neurology allowing the assessment of the functional consequences of white matter damage as well as the effectiveness of treatments in patients with any lesion that can be visualized by MRI.

Acoustic Stimulation↗

PubMed1999

CT and MRI of congenital sinonasal ossifying fibroma.

We report a 9-year-old boy with a sinonasal ossifying fibroma, probably congenital, with atypical findings on CT and MRI. CT revealed a soft-tissue density mass in the sphenoethmoidal sinuses, nasal cavity and right maxillary sinus with a few foci of calcification and with remodelling and destruction of the adjacent facial bones. MRI showed high signal on T2- and intermediate signal on T1-weighted images. A thin, partly enhancing outer shell and some nonenhancing septa were visible on contrast-enhanced images. MRI also showed the tumour to extend into the anterior cranial fossa. Subtotal removal was performed. We compare our findings with reports in the literature and discuss the differences from fibrous dysplasia.

Child↗

PubMed1999

MRI abnormalities in neurofibromatosis type 1 (NF1): a study of men and mice.

Hyperintense lesions on T2-weighted MR images of the brain, predominantly located in the basal ganglia, the brainstem and cerebellum, are a frequent finding in patients with neurofibromatosis type 1. Nature and significance of these lesions are still unknown so that the term 'unidentified bright objects' (UBOs) has been introduced to allow an unbiased description. We analyzed brain MRI scans of 31 children with definite diagnosis of neurofibromatosis type 1 according to the NIH criteria. High-intensity lesions on T2-weighted images were present in 86% of the patients. They did not correlate to other MRI findings such as optic pathway gliomas and were not indicative of intellectual impairment. Additionally, brain MR imaging of Nf1 knockout mice was performed to find out if similar abnormalities are present in this animal model. A total of 9 Nf1 knockout mice was examined on a dedicated animal MRI scanner at 4.7 Tesla but no evidence of high-signal intensity lesions on T2-weighted images was found. Therefore, the Nf1 mouse model seems to be unhelpful in providing further insights into the histological basis of hyperintense MRI abnormalities in NF1 patients.

Adolescent↗

PubMed1999

CT appearance of a renal aspergilloma in a patient with the acquired immunodeficiency syndrome.

The appearance of a unilateral renal aspergilloma on computed tomography is described in a 32-year-old man with acquired immunodeficiency syndrome (AIDS). Aspergillus infections are uncommon in the AIDS population. Only 9 cases of renal aspergilloma have been described in AIDS. The treatment performed was percutaneous drainage followed by antifungal drug administration and unilateral nephrectomy. This case report emphasizes the fact that renal fungal infections need to be considered in differential diagnosis of kidney infections in AIDS patients.

AIDS-Related Opportunistic Infections↗

PubMed1998

Megalencephaly, mega corpus callosum, and complete lack of motor development: a previously undescribed syndrome.

We report on 3 sporadic cases of in utero onset megalencephaly. Children were born to healthy nonconsanguineous parents after uneventful pregnancies. Head circumferences were just above the 97th centile at birth in 2 patients, 2 cm above the 97th centile in 1 patient, and subsequently increased to 4.5-6.5 cm above the 97th centile at age 5 years. All patients completely lacked motor and speech development and showed very little intellectual progress. There was a distinctive facial aspect with frontal bossing, low nose bridge, and large eyes, but no cutaneous abnormalities and no signs of other organ involvement. Magnetic resonance imaging showed bilateral megalencephaly with a broad corpus callosum, enlarged white matter, and focally thick gray matter, resulting in pachygyric appearance of the cortex. Opercularization was incomplete, and the Sylvian fissures were wide. Somatosensory evoked potentials in 1 patient showed normal latencies of cervical and contracortical potentials but bilaterally increased cortical amplitudes. To the best of our knowledge, no similar case observations have been recorded previously.

Agenesis of Corpus Callosum↗

PubMed1998

Focal grey matter heterotopias in monozygotic twins with developmental language disorder.

UNLABELLED: We describe 9-year-old monozygotic male twins with a developmental language disorder of the phonologic-syntactic type and learning difficulties. High-resolution MRI revealed bilateral parieto-temporal grey matter heterotopias in both twins, on the left more than on the right, and more pronounced in the more affected twin. This suggests a causal relationship between the heterotopias and the neuropsychological findings in this twin pair. CONCLUSION: Neuronal migration defects and ensuing focal heterotopias may be causally related to developmental language disorders.

Cerebral Cortex↗

PubMed1998

Paraneoplastic limbic encephalitis in two teenage girls.

Paraneoplastic neurological disorders represent remote effects of cancer without invasion of tumor cells into the nervous system. Limbic encephalitis is a distinct entity mostly associated with small-cell carcinoma of the lung. We present the cases of two teenage girls who were admitted with clinical symptoms typical for limbic encephalitis. In the course of the disease, they exhibited characteristic evolutionary changes of brain MRI abnormalities. Onset of neurological symptoms and type of underlying neoplasia were different in both patients. In one girl the initial workup led to the diagnosis of nodular sclerosing Hodgkin disease which so far had not caused any symptoms besides the described neurological abnormalities. A diagnostic brain biopsy showed inflammatory changes and excluded invasion of malignant cells into the central nervous system. The other patient had been diagnosed with a small cell carcinoma of the ovary several months before neurological and brain MRI abnormalities were observed. This is the first report in which clinical picture, evolution of MRI abnormalities, and--in one case--characteristic neuropathological changes are suggestive of paraneoplastic limbic encephalitis in two adolescent girls.

Adolescent↗

PubMed1998

Complete remission of a diffuse pontine glioma.

A patient is described in whom a large diffuse glioma of the pons extending into the midbrain was diagnosed at the age of 2 years. Biopsy showed a fibrillary astrocytoma. After shunting of a hydrocephalus, the clinical symptoms abated without conventional therapy. Repeated MRI studies showed a continuous decrease of the tumour which was no longer visible when the patient was 6.6 years old. In reviews on spontaneous remissions of oncologic disorders we were unable to find a case of a biologically benign brain stem tumour. There is one isolated report on a similar case, though without histologic documentation.

Antineoplastic Agents, Phytogenic↗

PubMed1998

Primitive neuroectodermal tumors of the cerebral hemispheres in two siblings with TP53 germline mutation.

AWe report on two siblings (brother and sister) who developed cerebral PNETs at the age of 5 years and 6 months, respectively. Both children were treated by operation followed by polychemotherapy. The brother also received cranio-spinal irradiation. Nevertheless, the children died about 12 months and 24 months post-operatively due to extensive cerebral tumor recurrences. Shortly after having lost both of her children, the mother developed an intra-abdominal tumor, which was resected and histologically diagnosed as ovarian carcinoma. Because of this unusual familial clustering of tumors and a positive history of brain tumors and other cancers in several maternal relatives, we analyzed DNA isolated from both PNETs and the ovarian carcinoma as well as constitutional (leukocyte) DNA from the whole family for mutation of the TP53 tumor suppressor gene. This analysis revealed that all tumors were homozygous for a missense mutation at codon 213 (CGA => TGG) resulting in an amino acid exchange from arginine to tryptophane. The same mutation was present in one TP53 allele in the constitutional DNA of the mother and the children, indicating that the mother had transmitted a TP53 germline mutation to both of her children. Analysis of loss of heterozygosity at microsatellite markers from 17p confirmed deletion of the paternal (wild-type) allele in both PNETs. Further investigation of the PNETs by comparative genomic hybridization revealed multiple chromosomal abnormalities. Interestingly, some genomic changes were common to both PNETs, while many others were not, a finding suggesting substantial genomic instability, probably as a consequence of p53 inactivation.

Adult↗

PubMed1997

[Radiologic diagnosis of primary extranodal lymphoma manifestations].

Primary extranodal lymphoma manifestation in the narrow sense is the term used to define the primary organ manifestation of a malignant lymphoma, excluding the thymus, spleen, Waldeyer's tonsillar ring, the appendix and Peyer's patches. However, in the clinical routine the term is also used for the secondary organ manifestation of underlying lymphoproliferative disease. Primary extranodal lymphomas are mainly non-Hodgkin lymphomas; there is primary extranodal manifestation of Hodgkin's disease in only about 1% of the cases. Among the extranodal NHL, the highly malignant forms predominate. A major exception is MALT lymphomas, which mainly show low slow growth. In the past, they were considered to be pseudolymphomas because of their slow and localized tumor growth. They were included as an entity of their own for the first time in the Revised European American Lymphoma (REAL) classification of 1994. The incidence data vary between < 10% and 25% for primary extranodal manifestation. The major reason for this is the difference in extranodal regions because of classification. Secondary organ involvement of an NHL occurs in up to 40% of the cases in the long-term course of the disease in primary nodal lymphomas. Secondary organ involvement is frequently diagnosed in AIDS patients who develop an AIDS-related lymphoma (85% of cases). The following contribution reports on the radiological imaging of extranodal lymphoma manifestation in the thoracoabdominal region.

Diagnosis, Differential↗

PubMed1997

The value of new MRI techniques in adrenoleukodystrophy.

PURPOSE: To evaluate the significance of new techniques in MRI examinations of the brain in children with X-linked adrenoleukodystrophy (ALD). MATERIALS AND METHODS: Five patients aged between 2 and 15 years with childhood ALD were examined with MRI. Following conventional spin-echo (CSE) sequence, a fast spin-echo (FSE) sequence with T2 contrast was performed in four patients, an FSE turbo-inversion-recovery (TIR) sequence in two, magnetization transfer contrast (MTC) imaging in two, and localized proton spectroscopy (MRS) in four patients. RESULTS: FSE compared favorably with CSE with a time saving of 70%. On TIR images the contrast between normal and demyelinated white matter was greater than on CSE and FSE images. Calculated MTC values revealed a severe MTC loss within the demyelinated regions and a moderate reduction in the border zones. In this way, calculation of MTC might be useful to differentiate between edematous changes and areas of irreversible demyelination. MRS revealed a reduction in N-acetylaspartate and an elevation in choline (Cho). The degree of MRS changes paralleled the severity of demyelination. A Cho elevation may precede visible demyelination on T2-weighted images. CONCLUSIONS: T2-weighted FSE sequences can replace CSE without any disadvantages and with effective time saving. The indication for MTC imaging and MRS in children with ALD is not yet finally defined. These new techniques may reveal the earliest signs of cerebral involvement or of disease progression, a matter of great importance in selecting the optimal therapeutic approach.

Adolescent↗