Biomedical subjects

R Klingebiel

Publications and source records attributed to R Klingebiel.

15 recordsLinked to original sources

PubMed2003

[Langerhans cell histiocytosis: petrosal remodelling after chemotherapy--case report and review of the literature].

We report the case of a child presented by her parents to the ENT outpatient service for swelling of the right temporal bone. The child had a history of recurrent bilateral inflammation of the middle ear. Tympanometry revealed a reduced compliance. Due to conductive hearing loss it was impossible to measure otoacustic emissions. Otherwise a normal ENT status was found. Imaging (MRI/CT) demonstrated bitemporal soft-tissue changes with extensive osseous destruction, but no typical imaging signs of an inflammatory, dysplastic or expansive process. The tentative diagnosis of Langerhans' cell histiocytosis (LCH) made on the basis of the clinical and imaging findings was confirmed by biopsy. After exclusion of disseminated LCH, chemotherapy was initiated, and the child underwent follow-up imaging after 3 months. CT showed clear signs of bitemporal reossification. The case reported here illustrates the problems encountered in diagnosing LCH which may present with unspecific clinical symptoms despite advanced osseous destruction. ENT specialists should be familiar with this very heterogeneous entity and think of LCH especially in children presenting with therapy-refractory otitis media, otitis externa, or mastoiditis in order to ensure a timely diagnosis and to thus improve the chances of successful therapy. Imaging modalities (CT, MRI) have a role in the early diagnosis and follow-up of this disorder.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2003

[Bilateral spontaneous development of a frontal sinus pyocele--a rare diagnosis].

Due to the length and the narrowing of the sinus draining passage, mucoceles are typically located within the frontal sinus. This case report describes the pathology of a patient with bilateral formation of pyoceles of the frontal sinus without the history of trauma, sinus operation or nasal pathology. The patient visited an ophthalmologist and reported a slowly increasing visual loss and protrusion of the left bulbus in the course of one year. Coronal CT scan showed bilateral soft tissue densities within the frontal sinus with arrosion of the floor on the left side. Extranasal frontal sinus surgery with ethmoidectomy (Ritter-Jansen and Uffenorde mucosal plasty) was performed. Intraoperative view demonstrated bony defects of the floor and the posterior wall of the frontal sinus.

Aged↗

PubMed2003

[Quantitative perfusion imaging by multi-slice CT in stroke patients].

OBJECTIVES: Evaluation of a parametric deconvolution algorithm (DA) in the diagnostic assessment of stroke patients by multi- slice spiral computed tomography (MS-CT). MATERIAL AND METHODS: 52 patients (age range 34 - 89 years) with clinically suspected acute ischemia of one hemisphere and no infarct demarcation on plain cerebral CT underwent CT perfusion (CTP), performed on average 3.4 hours after the onset of symptoms by using MS-CT (4 x 8 mm scan volume). Using a DA-based software module, perfusion images of the cerebral blood perfusion (CBP), cerebral blood volume (CBV) and mean transit time (MTT) were calculated and assessed by two readers for visually apparent perfusion abnormalities. Amount and extension of perfusion disturbances were measured and correlated with the outcome. RESULTS: Of 44 patients, in whom perfusion maps could be generated, territorial infarction was confirmed by follow-up in 22 subjects. With a sensitivity of 95 % ischemia could be detected on MTT-maps (CBP 91 %, CBV 77 %). Specificity was highest (100 %) for CBV-maps. Patients with infarction showed significant (p < 0.001) reduction of CBP (10.7 vs. 38.3 ml/100 ml/min), CBV (1.3 vs. 2.3 ml/100 ml) and prolongation of MTT (12.3 vs. 4.3 s) compared to the contralateral hemisphere, whereas in patients without infarction no significant changes were found. Extension of CBV reduction showed the best correlation (r = 0.82) with final infarct volume. CONCLUSION: The DA-based CTP protocol evaluated in this study is a suitable tool for the early identification and quantification of acute cerebral ischemia.

Adult↗

PubMed2003

Visualization of the pulmonary valve using cine MR imaging.

PURPOSE: To evaluate the capability of bright-blood cine MR to directly visualize the leaflets of the valve replacement in pulmonary position following Ross operation. MATERIAL AND METHODS: Long and short axis views of the pulmonary valve were obtained in 10 normal subjects and 14 patients after Ross operation. Valve morphology and function were analyzed and signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were calculated. Flow measurements were performed in the pulmonary trunk to assess pulmonary regurgitation. RESULTS: In all subjects, tricuspid morphology of the pulmonary valve was visualized. SNR of the leaflets in normal subjects (9.8 +/- 3.0) and in patients after Ross operation (7.5 +/- 2.2) differed significantly from blood (12.6 +/- 3.2 and 11.3 +/- 2.5, respectively, p < 0.05). Valvular regurgitation was seen in 5 patients as an insufficient closure of the valve which was confirmed by flow measurements. CONCLUSION: Cine MR enables in-plane visualization of the pulmonary valve and allows for functional and morphological evaluation in patients after pulmonary valve surgery.

Adult↗

PubMed2002

[Using multislice spiral CT in neuroradiologic imaging].

Multislice computed tomography (MS-CT) was introduced into clinical radiology in 1999 and has shown a significant effect on various indications for computed tomography (CT) imaging in neuroradiology. Technical highlights of this new scanner type are the simultaneous data acquisition by up to four detector rows at present, an accelerated rotation time, and a reduction of the slice thickness to as low as 0.5 mm. These features account for an extended scan area, such as head and neck imaging in polytraumatized patients, detailed contrast-enhanced studies of the cervicocerebral vascular system from the carotid bifurcation to the vertex, as well as cerebral perfusion studies of a larger brain volume with an improved time resolution compared to established CT procedures. In addition, the diagnostic yield of the CT is increased with respect to several applications by reducing common image artefacts at the level of the cervicothoracic junction as well as those caused by metallic implants. Apart from improving the image quality of the primary cross-sectional slices, MS-CT significantly enhances two- and three-dimensional image reconstructions. Radiation protection is an important issue with MS-CT, especially when skull base imaging is considered.

Artifacts↗

PubMed2002

Large cerebral vessel occlusive disease in Lyme neuroborreliosis.

We report on a 12-year-old, previously healthy girl with an acute hemiparesis as the predominant clinical manifestation of Lyme neuroborreliosis (LNB). The diagnosis of LNB was based on cerebrospinal fluid (CSF) studies, laboratory findings and the clinical course whereas the patient's history and the lack of characteristic skin lesions obscured the diagnosis in the beginning. After four weeks of antibiotic and physiotherapeutic treatment, the hemiparetic symptoms had completely resolved. Although evidence of vasculitic and perivascular inflammation in LNB has been described in the literature, large cerebral vessel occlusive disease represents a rare finding. Appropriate treatment strategies can lead to good clinical rehabilitation, as shown in this case, making the timely diagnosis a crucial issue. We conclude that LNB should be considered in every stroke-like episode of unknown origin in children, even in the absence of a history of a tick bite or typical skin lesions.

Arterial Occlusive Diseases↗

PubMed2002

Three-dimensional MR visualization of the intracisternal course of the cranial nerves V-VIII by virtual cisternoscopy.

PURPOSE: A post-processing protocol for 3D visualization of the cranial nerves V-VIII along their intracisternal course is presented. MATERIAL AND METHODS: Six healthy volunteers underwent MR imaging (1.5 T) to obtain high-resolution heavily T2-weighted data sets (3DFT CISS) with isotropic voxels (0.5 mm3). The data sets were post-processed by using volume rendering software in order to visualize the intracisternal courses of the cranial nerves V-VIII as well as their root entry zones. The data acquisition and post-processing protocol was then applied in 14 patients with a suspected neural compression syndrome according to the clinical findings as well as cross-sectional images and evaluated with respect to image quality and diagnostic value by two neuroradiologists, using a five-point scale. RESULTS: Virtual cisternoscopy allowed a comprehensive intracisternal 3D visualization of the affected cranial nerves in 12/14 patients. The mean post-processing time amounted to 13.1/5.6/13.7 min for the cranial nerves V/VI/VII and VIII. The mean score for image quality was 4.2, that for diagnostic value 4.1. 2D and/or 3D reference images were indispensable for appreciating the spatial information provided by virtual cisternoscopy. CONCLUSION: The data acquisition and post-processing protocol presented here allows comprehensive and standardized intracisternal 3D visualization of the cranial nerves V-VIII in a routine setting as a complementary imaging procedure.

Abducens Nerve↗

PubMed2001

[Virtual rendering techniques in otologic imaging].

UNLABELLED: Virtual postprocessing techniques combine the advantages of condensing the large amounts of data provided by high-resolution (HR) cross-sectional imaging modalities with those of three-dimensional (3D) imaging. The techniques and indications for virtual representations in imaging of the middle ear (ME), internal ear (IE), and cerebellopontine angle (CPA) are presented together with practical examples. MATERIAL AND METHODS: HR data sets acquired by computed tomography (CT) and magnetic resonance imaging (MRI) in patients with ME, IE, and CPA pathologies were transferred to a workstation via an internal network to generate endo- or extraluminal 3D views by means of the volume rendering technique (VRT). The source data were acquired using scanners and imaging protocols with the highest resolution available at present: a multislice spiral CT (MSCT) with a slice thickness of 0.5 mm and a reconstruction increment of 0.2 mm and a 3D CISS sequence with a slice thickness of 0.5 mm for MRI. RESULTS: Virtual endoscopy was superior to cross-sectional images for assessing ME pathologies like dysplasia, postoperative changes, and destructive bone processes with extensive soft-tissue involvement; fibrous obliterations of the internal ear and labyrinthine dysplasia were depicted with a superior image quality on 3D renderings compared to conventional reconstruction techniques. Virtual endoscopy of the CPA and external acoustic meatus (EAM) was helpful in detecting and visualizing neurovascular conflicts and in assigning small intrameatal tumors to components of the acousticofacial bundle. A common feature of all applications was that the large numbers of source images could be reduced to a few 3D reconstructions for documentation and optimized communication of the findings between the radiologist and otologist. CONCLUSION: Virtual rendering makes an important contribution towards establishing, presenting, and documenting the findings when certain otologic pathologies have to be assessed. It can be used for routine imaging and allows for more efficient handling of the large amounts of imaging data generated by high-resolution cross-sectional imaging modalities.

Cerebellopontine Angle↗

PubMed2001

A post-processing protocol for three-dimensional visualization of the inner ear using the volume-rendering technique based on a standard magnetic resonance imaging protocol.

A superior diagnostic quality compared to other post-processing (PP) techniques for three-dimensional (3D) inner ear imaging has been attributed to volume rendering (VR). We defined and assessed a VR protocol for 3D visualization of the inner ear in a routine imaging setting. Following definition of a VR protocol by using lower threshold values, surface shading, perspective views and related parameters, standardized 3D views of the inner ear were generated and evaluated in 32 patients suffering from sensorineural or combined hearing loss. Comprehensive inner ear visualization was achieved in 28 patients by means of two 3D shaded-surface views. Incomplete data acquisition (1/32), motion and pulsation artefacts (2/32) and interposed fluid-retaining mastoid cells (1/32) were responsible for non-diagnostic image quality in 4/32 patients. In 5/32 patients modifications of the PP protocol involving the threshold value and depth-cueing parameters helped to establish diagnostic image quality. Mean post-processing time amounted to 5.8 min per site. 3D imaging with the VR technique is suitable for routine inner ear assessment if direct VR, predefined PP protocols and standardized labyrinthine views are used.

Artifacts↗

PubMed2001

High-resolution petrous bone imaging using multi-slice computerized tomography.

Multi-slice computerized tomography (MSCT) is considered to provide superior image quality. We defined a data acquisition protocol for high-resolution (HR) temporal bone imaging using MSCT and assessed its impact on data acquisition and post-processing (PP). The data acquisition protocol was defined in cadaveric phantom studies performed by MSCT and subsequently applied to 38 patients referred for temporal bone assessment. The parameters image quality and diagnostic value of MSCT data were assessed for the cross-sectional source images as well as for 2-dimensional (2D) reformations and 3-dimensional (3D) reconstructions by 3 radiologists by comparison with incremental HR scans of 17 patients with suspected middle ear disorders. The data acquisition protocol yielded HR images with an excellent detail resolution and a comparable image quality of cross-sectional scans and related orthogonal reformations. MSCT achieved higher scores for image quality and diagnostic value (p < 0.001, t-test) than incremental HR CT with regard to both 2D and 3D reconstructions. MSCT improves the image quality of HR cross-sectional scans as well as that of 2D and 3D PP techniques in petrous bone imaging. The radiation exposure of the eye lenses is increased by MSCT as gantry angulation is not yet possible in the helical scan mode.

Algorithms↗

PubMed2001

Assessment of the arteriovenous cerebrovascular system by multi-slice CT. A single-bolus, monophasic protocol.

PURPOSE: We present a protocol for the non-invasive angiographic assessment of the arterial and venous cerebrovascular (CV) system by multi-slice CT. MATERIAL AND METHODS: Data acquisition was performed in a multi-slice CT scanner with a scan range from the carotid bifurcation to the vertex and manual scan start following i.v. administration of 120 ml iodinated contrast medium with a flow rate of 4 ml/s. This protocol was applied in 12 patients with symptoms of acute CV insuffiency. RESULTS: In all patients, comprehensive imaging of the arteriovenous CV system was achieved including the common carotid bifurcation, the third segment of the major cerebral arteries, the dural sinus and the internal cerebral veins. Various CV pathologies, such as a territorial artery occlusion, a thrombotic obstruction of the internal carotid artery, an intracranial arteriovenous malformation and a sinus vein thrombosis, were successfully evaluated. CONCLUSION: Comprehensive assessment of the arteriovenous CV system is possible by the use of a single-bolus, monophasic multi-slice scan technique.

Adult↗

PubMed2001

Visualization of inner ear dysplasias in patients with sensorineural hearing loss.

PURPOSE: We evaluated a data acquisition and post-processing protocol for inner ear (IE) assessment by MR imaging in patients, suffering from various labyrinth malformations. MATERIAL AND METHODS: MR IE studies of 158 consecutive patients (316 IEs) suffering from sensorineural hearing loss without evidence of an acoustic neurinoma were reviewed for pathologies of the IE and internal acoustic meatus. High-resolution MR data of all abnormal IE studies (n=45) were post-processed to previously standardized 3D volume rendered (VR) reconstructions. RESULTS: In 9 patients (5.7%) the following IE dysplasias were detected: malformation of the cochlea (6 IEs), vestibulum (4 IEs), semicircular canals (12 IEs) and vestibular aqueduct/endolymphatic sac (10 IEs). One patient showed evidence of an aplasia of the vestibulocochlear nerve. In 4 patients multiple IE dysplasias were encountered. Comprehensive 3D visualization of all labyrinthine dysplasias was achieved by the use of two VR reconstructions. The overall time for bilateral IE assessment amounted to 30-35 min. CONCLUSION: The imaging protocol allows for rapid and comprehensive visualization of various IE dysplasias, based on a limited number of VR reconstructions.

Adolescent↗

PubMed2001

Virtual endoscopy of the tympanic cavity based on high-resolution multislice computed tomographic data.

OBJECTIVE: This study was designed to assess the value of high-resolution multislice computed tomography (MSCT) data of the petrous bone for the virtual endoscopic visualization of the tympanic cavity. BACKGROUND: The recently introduced MSCT technology has improved spatial resolution in the z axis as well as scan speed in computed tomography. Three-dimensional rendering of high-resolution MSCT data of the petrous bone may be expected to provide endoluminal views of superior image quality, thus competing with transtympanic endoscopy (otoendoscopy). SETTING: This study was conducted at a university teaching hospital. MATERIALS AND METHODS: Cadaveric phantom studies in a MSCT scanner were performed to define a data acquisition protocol, combining adequate detail resolution with low tube current. Subsequently, the cadaveric phantom underwent otoendoscopy. The postprocessing parameters of the three-dimensional rendering protocol were chosen to produce views closely resembling the corresponding otoendoscopic images. High-resolution data from 18 patients with pathologic conditions of the middle ear, as suggested by clinical findings and assessment of cross-sectional data, were postprocessed using the volume rendering technique to generate standardized virtual endoscopic views. A total of 36 virtual endoscopic scans of the tympanic cavity were generated. RESULTS: With regard to intermediate and high-density structures, virtual endoscopic images, based on MSCT data, yielded endoluminal views closely resembling corresponding otoendoscopic views. Virtual endoscopy seems useful for imaging ossicular pathologic conditions such as dysplasia and chain disruption as well as for assessing patient status before and after otosurgery. CONCLUSION: MSCT data sets allow for generating virtual endoscopic views closely resembling otoendoscopic images. The technique is especially useful when ossicular pathologic changes are present as well as for preoperative and postoperative imaging of otologic procedures.

Endoscopy↗

PubMed2000

[Virtual otoscopy--technique, indications and initial experiences with multislice spiral CT].

UNLABELLED: We report the standardized postprocessing of high-resolution CT data acquired by incremental CT and multi-slice CT in patients with suspected middle ear disorders to generate three-dimensional endoluminal views known as virtual otoscopy. MATERIALS AND METHODS: Subsequent to the definition of a postprocessing protocol, standardized endoluminal views of the middle ear were generated according to their otological relevance. The HRCT data sets of 26 ENT patients were transferred to a workstation and postprocessed to 52 virtual otoscopies. RESULTS: Generation of predefined endoluminal views from the HRCT data sets was possible in all patients. Virtual endoscopic views added meaningful information to the primary cross-sectional data in patients suffering from ossicular pathology, having contraindications for invasive tympanic endoscopy or being assessed for surgery of the tympanic cavity. Multi slice CT improved the visualization of subtle anatomic details such as the stapes suprastructure and reduced the scanning time. CONCLUSION: Virtual endoscopy allows for the non invasive endoluminal visualization of various tympanic lesions. Use of the multi-slice CT technique reduces the scanning time and improves image quality in terms of detail resolution.

Adolescent↗

PubMed1995

Phagocytosis and chemotaxis of rat alveolar macrophages after a combined or separate exposure to ozone and carbon black.

Male Wistar rats were treated by ozone or carbon black (CB) alone as well as in combination. Intratracheal instillation with various amounts of CB was followed either by an acute 7-day or subchronic 2-month ozone exposure (0.5 ppm). Two functional parameters were investigated in alveolar macrophages from bronchoalveolar lavagates, the phagocytotic capacity and the chemotactic migration capability. In the phagocytosis assay, the percentage of phagocytizing macrophages decreased significantly in the CB-exposed groups whereas the ozone groups remained close to or at the control level after 7 days and 2 months of exposure, respectively. The number of ingested particles per macrophage and the formation of superoxide anion radicals were not changed after a 7-day exposure to ozone compared to the control group but were increased after a 2-month ozone exposure. However, a reduction was found in the CB groups. A stimulating effect of ozone was observed in the combined groups. Chemotactic migration was generally retarded in the CB-treated groups. From the results it can be concluded that ozone is able to stimulate the phagocytotic and chemotactic activity of alveolar macrophages whereas CB impairs these functions.

Administration, Inhalation↗