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L van den Hauwe

Publications and source records attributed to L van den Hauwe.

At least 19 recordsLinked to original sources
PubMed2006

Functional MRI of the cervical spinal cord on 1.5 T with fingertapping: to what extent is it feasible?

INTRODUCTION: Until recently, functional magnetic resonance imaging (fMRI) with blood oxygen level-dependent (BOLD) contrast, was mainly used to study brain physiology. The activation signal measured with fMRI is based upon the changes in the concentration of deoxyhaemoglobin that arise from an increase in blood flow in the vicinity of neuronal firing. Technical limitations have impeded such research in the human cervical spinal cord. The purpose of this investigation was to determine whether a reliable fMRI signal can be elicited from the cervical spinal cord during fingertapping, a complex motor activity. Furthermore, we wanted to determine whether the fMRI signal could be spatially localized to the particular neuroanatomical location specific for this task. METHODS: A group of 12 right-handed healthy volunteers performed the complex motor task of fingertapping with their right hand. T2*-weighted gradient-echo echo-planar imaging on a 1.5-T clinical unit was used to image the cervical spinal cord. Motion correction was applied. Cord activation was measured in the transverse imaging plane, between the spinal cord levels C5 and T1. RESULTS: In all subjects spinal cord responses were found, and in most of them on the left and the right side. The distribution of the activation response showed important variations between the subjects. While regions of activation were distributed throughout the spinal cord, concentrated activity was found at the anatomical location of expected motor innervation, namely nerve root C8, in 6 of the 12 subjects. CONCLUSION: fMRI of the human cervical spinal cord on an 1.5-T unit detects neuronal activity related to a complex motor task. The location of the neuronal activation (spinal cord segment C5 through T1 with a peak on C8) corresponds to the craniocaudal anatomical location of the neurons that activate the muscles in use.

Adolescent↗
PubMed2004

Spinal tumors.

Spinal tumors are uncommon lesions but may cause significant morbidity in terms of limb dysfunction. In establishing the differential diagnosis for a spinal lesion, location is the most important feature, but the clinical presentation and the patient's age and gender are also important. Magnetic resonance (MR) imaging plays a central role in the imaging of spinal tumors, easily allowing tumors to be classified as extradural, intradural-extramedullary or intramedullary, which is very useful in tumor characterization. In the evaluation of lesions of the osseous spine both computed tomography (CT) and MR are important. We describe the most common spinal tumors in detail. In general, extradural lesions are the most common with metastasis being the most frequent. Intradural tumors are rare, and the majority is extramedullary, with meningiomas and nerve sheath tumors being the most frequent. Intramedullary tumors are uncommon spinal tumors. Astrocytomas and ependymomas comprise the majority of the intramedullary tumors. The most important tumors are documented with appropriate high quality CT or MR images and the characteristics of these tumors are also summarized in a comprehensive table. Finally we illustrate the use of the new World Health Organization (WHO) classification of neoplasms affecting the central nervous system.

Humans↗
PubMed2003

Contrast enhancement in Lhermitte-Duclos disease of the cerebellum: correlation of imaging with neuropathology in two cases.

Lhermitte-Duclos disease (LDD), also known as dysplastic gangliocytoma, is a rare cerebellar lesion. It has long been regarded as avascular. We report two patients with surgically proven LDD in whom contrast enhancement was observed on MRI. Neuropathological examination revealed proliferation of veins. We suggest that peripheral enhancement of LDD probably reflects vascular proliferation of the cerebellar venous draining system, and should be considered part of the imaging features of LDD.

Adult↗
PubMed2001

Intracranial hemorrhage: principles of CT and MRI interpretation.

Accurate diagnosis of intracranial hemorrhage represents a frequent challenge for the practicing radiologist. The purpose of this article is to provide the reader with a synoptic overview of the imaging characteristics of intracranial hemorrhage, using text, tables, and figures to illustrate time-dependent changes. We examine the underlying physical, biological, and biochemical factors of evolving hematoma and correlate them with the aspect on cross-sectional imaging techniques. On CT scanning, the appearance of intracranial blood is determined by density changes which occur over time, reflecting clot formation, clot retraction, clot lysis and, eventually, tissue loss. However, MRI has become the technique of choice for assessing the age of an intracranial hemorrhage. On MRI the signal intensity of intracranial hemorrhage is much more complex and is influenced by multiple variables including: (a) age, location, and size of the lesion; (b) technical factors (e.g., sequence type and parameters, field strength); and (c) biological factors (e.g., pO2, arterial vs. venous origin, tissue pH, protein concentration, presence of a blood-brain barrier, condition of the patient). We discuss the intrinsic magnetic properties of sequential hemoglobin degradation products. The differences in evolution between extra- and intracerebral hemorrhages are addressed and illustrated.

Brain↗
PubMed2000

The value of MRI in the diagnosis of postoperative spondylodiscitis.

We evaluated the role of MRI in the diagnosis of postoperative spondylodiscitis. Spondylodiscitis is a serious complication of surgery, and the diagnosis frequently depends on a combination of clinical, laboratory and imaging findings. We compared the MRI findings in six patients with biopsy- or surgery-proven spondylodiscitis with those in 38 asymptomatic postoperative patients. Contrast enhancement and signal changes in the intervertebral disc or the vertebral endplates are not specific for spondylodiscitis, being also seen in the asymptomatic patients. However, absence of Modic type 1 changes, of contrast enhancement of the disc or of enhancing paravertebral soft tissues suggests that the patient does not have spondylodiscitis. MRI appears more useful for exclusion than for confirmation of postoperative spondylodiscitis.

Discitis↗
PubMed2000

Amyloidoma of the skull base.

We report a case of a primary amyloidoma of the skull base. Plain radiography and CT showed a lytic, highly destructive lesion with multiple scattered calcifications within. MR imaging revealed that the tumor was isoto hypointense to muscle on T1-weighted images and extremely hypointense on T2-weighted images. In contrast to two previous reports, marked enhancement after the administration of contrast material was absent. Bone amyloidomas are very rare and are frequently misinterpreted as chondrosarcomas.

Amyloidosis↗
PubMed2000

Maxillo-facial trauma.

Injuries to the facial bones, orbits and adjacent soft tissue structures are common. Despite the increasing safety precautions in modern cars, facial injury is very often caused by motor vehicle accidents. Severe trauma to the face is a strong indication for radiological investigation. In the patient with maxillo-facial trauma, the radiological exploration of should answer two major questions: do the fractures involve areas that may alter the physiologic function of the sinuses, mouth, nasal vault or orbit?, and will the fracture result in any cosmetically detectable abnormality? The goal of the radiological work-up is to define the number and exact location of the fractures, to determine if there is any depression, elevation, or distraction of the fracture fragments, and to assess concomitant soft tissue complications. In this article, we review the role of clinical evaluation, plain X-rays, computed tomography (CT) and magnetic resonance imaging (MRI). Imaging findings are correlated with anatomic and physiopathologic considerations. We present a practical classification system of facial trauma, with emphasis on trauma of the paranasal sinuses and facial bones (nasal and tripod fractures, Le Fort fractures) and orbits (foreign bodies, soft tissue and orbital wall injuries such as blow-in and blow-out-, lateral wall- and apical fractures). A third part focuses on trauma of the mandible and the temporomandibular joints.

Diagnostic Imaging↗
PubMed1999

Computer assisted E.N.T. surgery, a preliminary report.

The Medivision Image Guided Surgery System was used in the E.N.T. Department of the Antwerp University Hospital in 10 different E.N.T. surgical procedures between October 1997 and February 1998. The authors report and discuss the procedure for computer assisted surgery in E.N.T. interventions, based on this preliminary experience, and conclude that computer assisted surgery has many useful applications in our speciality.

Humans↗
PubMed1998

Imaging findings in diffuse axonal injury after closed head trauma.

Even in patients with closed head trauma, brain parenchyma can be severely injured due to disruption of axonal fibers by shearing forces during acceleration, deceleration, and rotation of the head. In this article we review the spectrum of imaging findings in patients with diffuse axonal injuries (DAI) after closed head trauma. Knowledge of the location and imaging characteristics of DAI is important to radiologists for detection and diagnosis. Common locations of DAI include: cerebral hemispheric gray-white matter interface and subcortical white matter, body and splenium of corpus callosum, basal ganglia, dorsolateral aspect of brainstem, and cerebellum. In the acute phase, CT may show punctate hemorrhages. The true extent of brain involvement is better appreciated with MR imaging, because both hemorrhagic and non-hemorrhagic lesions (gliotic scars) can be detected. The MR appearance of DAI lesions depends on several factors, including age of injury, presence of hemorrhage or blood-breakdown products (e. g., hemosiderin), and type of sequence used. Technical aspects in MR imaging of these patients are discussed. Non-hemorrhagic lesions can be detected with fluid attenuated inversion recovery (FLAIR), proton-density-, or T2-weighted images, whereas gradient echo sequences with long TE increase the visibility of old hemorrhagic lesions.

Adolescent↗
PubMed1998

An unusual case of maxillary ameloblastoma.

We report a case of malignant maxillar ameloblastoma. A review of literature is presented. The unusual clinical behavior and the non specific presentation on CT of our case are discussed.

Ameloblastoma↗
PubMed1997

Imaging of primary tumors and tumor-like conditions of the lumbosacral osseous spine.

Primary tumors of the osseous spine are rare. This article illustrates some aspects of imaging of tumoral pathology of the osseous spine. Plain film and CT scan still remain the initial imaging modalities in the work-up of tumoral pathology of the osseous spine. MR imaging however has proven its potentials in the detection of lesions in areas with superimposing structures which hamper reliable reading of the plain films or in areas with a complex bony anatomy such as the sacrum. MR imaging is exquisite in determining the local extent of tumoral lesions and in defining the relationship to adjacent central nervous system structures. In some tumors or tumor-like lesions, MR imaging allows to make a correct tissue-related diagnosis or to strengthen the diagnosis made on plain film/CT observations. In other case MR imaging only has a role in staging or may have definitely no role at all.

Adult↗
PubMed1997

Imaging findings in patients with failed back surgery syndrome.

The incidence of low back pain and leg pain related to the spine is very high in the Western population. As a result of conservative treatment failure there are roughly 200,000 lumbar disk operations performed annually. Unsuccessful surgical outcome is known as the failed back surgery syndrome (FBSS). FBSS is a complex and poorly understood syndrome, with as many different imaging findings as different possible etiologic mechanisms. Still we believe some imaging aspects deserve special attention. Firstly it is of particular importance to correctly differentiate residual disk herniation from epidural scar tissue since disk herniation can be an indication for repeat intervention. Secondly when residual disk herniation is present, one should keep in mind that it is not necessarily responsible for the patients complaints. Thirdly, late nerve root enhancement should be considered as pathological. Finally one should be aware of the mechanical back stress that may develop as a result of discectomy. One of the consequences can be secondary foraminal stenosis which is probably one of the most common causes of FBSS.

Cicatrix↗
PubMed1997

MR of the brain in Sjögren-Larsson syndrome.

Cerebral MR was performed in three patients with Sjögren-Larsson syndrome. In each case, a 1.5-T system was used, and the patient was under general anesthesia. The MR findings included confluent hyperintense white matter lesions in the periventricular and deep white matter of the centrum semiovale, with sparing of the subcortical U fibers. The topography of the white matter abnormalities correlated well with the clinical signs and symptoms.

Adult↗
PubMed1996

Clinical usefulness of contrast-enhanced MP-RAGE of the brain.

Our purpose was to evaluate the usefulness of a 3D T1-weighted gradient-echo sequence (MP-RAGE) in clinical practice. We prospectively examined 200 patients with a variety of neurological disorders and symptoms. We compared lesion conspicuity and contrast enhancement on MP-RAGE images with conventional gadolinium-enhanced spin-echo (SE) T1-weighted images. Both the original MP-RAGE data and the reformatted images were characterised by improved differentiation between grey and white matter. More lesions were found on the 3D series, in both patients with neoplastic and non-neoplastic disease. Contrast enhancement of small oedematous lesions affecting the white matter in demyelinating disease was less obvious. Multiplanar reformatting, which can be realised in any desired plane and surface rendering with sophisticated segmentation algorithms superbly displayed the underlying anatomical relationships between lesions and normal brain structures. Excellent spatial resolution, the absence of posterior fossa artefacts and equivalent contrast enhancement resulted in an increased number of space-occupying lesions being found on the MP-RAGE images. Thus contrast-enhanced MP-RAGE is an alternative to conventional SE imaging in the investigation of intracranial masses. Although the total number of lesions found in patients with demyelinating disease was significantly higher on MP-RAGE, demonstration of blood-brain-barrier breakdown in active lesions was less obvious.

Adult↗