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Biomedical subjects

C Fellner

Publications and source records attributed to C Fellner.

At least 37 records · Page 2Linked to original sources
PubMed1999

The value of T2(*)-weighted MR images for the diagnosis of acoustic neuromas.

UNLABELLED: The aim of this study was to evaluate high resolution T2(*)-weighted MRI--in our case a 3D CISS sequence--for the diagnosis of acoustic neuromas. Especially to be clarified was if high-resolution T2-weighted sequences can substitute T1-weighted contrast-enhanced sequences, and in which circumstances they can give important additional information when compared with contrast-enhanced T1-weighted sequences. METHODS AND PATIENTS: The MR examinations were performed using a 1.5-Tesla unit with a circularly polarized head coil. All 20 patients (11 females, nine males, aged from 12 to 80 years) with acoustic neuromas underwent preoperative MRI with T2*-weighted 3D CISS (slice thickness, 0.7 mm; acquisition time, 8 min) and pre- and postcontrast T1-weighted 3D MP-RAGE (slice thickness, 0.9 mm; acquisition time, 8 min) sequences. The detectability of acoustic neuromas was evaluated following the consensus of three radiologists using a 3D work station (parameters: tumor presence, extent, nerve attribution). RESULTS: All tumors were detected by both contrast-enhanced 3D MP-RAGE and 3D CISS and the diameters of the lesions were equally well measured. 3D CISS was the best sequence for the attribution of a lesion to a certain nerve. Labyrinthine involvement could be better detected using 3D CISS than contrast-enhanced 3D MP-RAGE. CONCLUSION: High-resolution T2(*)-weighted MRI is a very sensitive method for tumor screening which can also detect even small meatal and labyrinthine neuromas. In the case of abnormal findings (other pathology or variations, e.g. vascular loops); however, contrast-enhanced T1-weighted MRI is necessary in order to confirm the presence of a tumor with typical enhancement.

Adult↗
PubMed1999

Functional MR imaging of the motor cortex in healthy volunteers and patients with brain tumours: qualitative and quantitative results.

The purpose of this study was to compare functional magnetic resonance (MR) imaging of the motor cortex in healthy volunteers and patients with brain tumours. Functional MR imaging was performed in 14 healthy volunteers and 14 patients with tumours in or near the primary motor cortex with groups being matched for age, sex, and handedness. Functional images were acquired during motion of the right and left hand. Time courses of signal intensity within the contralateral, ipsilateral, and supplementary motor cortex as well as z-maps were calculated, their quality being assessed visually. Mean signal increase between activation and rest were evaluated within the contralateral, ipsilateral, and supplementary motor cortex, the activated area in those regions of interest was measured using z-maps. The quality of functional MR experiments was generally lower in patients than in volunteers. The quantitative results showed a trend towards increased ipsilateral activation in volunteers during left hand compared to right hand motion and in patients during motion of the affected compared to the non-affected hand. Considering quantitative and qualitative results, significantly increased ipsilateral activation was found in patients compared to healthy volunteers. In conclusion, functional MR imaging quality was significantly reduced in patient studies compared to healthy volunteers, even if influences of age, sex, and handedness were excluded. Increased ipsilateral activation was found in patients with brain tumours which can be interpreted by an improved connectivity between both hemispheres.

Adult↗
PubMed1999

Contrast enhanced MRA of peripheral arteries with the automatic "floating table".

Magnetic resonance angiography (MRA) is increasingly used as a non-invasive alternative to digital subtraction angiography (DSA). Besides plain time-of-flight (TOF) and phase contrast (PC) MRA a new MRA technique using positive contrast agent has been introduced recently. A fast 3D gradient-echo sequence is applied to reach a significant reduction of measurement time for acquisition of the MRA within the first pass of the contrast agent, thereby avoiding venous overlap. A significant progress was yielded by MR systems allowing manual table movement for examination of the pelvis and the lower limbs in one examination with a single contrast agent bolus. However, in this case it is necessary to have a coworker in the examination room moving the table manually. In this paper we report a prototype system which allows automatic table movement ("floating table"). Using this novel system we examined a patient with an aneurysm of the abdominal aorta and peripheral arterial occlusive disease (PAOD). Diagnostic results of contrast enhanced MRA and DSA were equivalent. In summary, the automatic floating table system introduced in this paper allows comfortable non-invasive examination of pelvic and lower limb arteries. The value of this technique in comparison to DSA has to be determined in future studies.

Arterial Occlusive Diseases↗
PubMed1999

Gd-BOPTA: "the MRA contrast agent of choice"?

Gd-BOPTA is a new positive MR contrast agent for intravenous application. In comparison to other gadolinium-chelates it has a nearly two-fold increased relaxivity due to weak protein binding with plasmatic macromolecules. In the papers published yet it has been evaluated to be useful for liver imaging. The purpose of this study was to evaluate, whether Gd-BOPTA is suited as an "magnetic resonance angiography (MRA) contrast agent". We examined four patients (aortic dissection, carotid artery stenosis, portal vein stenosis, exclusion of subclavian artery stenosis) with Gd-BOPTA with a dosage of 0.05 mmol/kg body weight. Furthermore, peripheral MRA of the pelvis and lower extremities was acquired in two healthy volunteers comparing 0.1 mmol Gd-DTPA/kg with 0.1 mmol Gd-BOPTA/kg. There was a delay of one week between the Gd-DTPA and the Gd-BOPTA examinations. In another volunteer Gd-BOPTA was reduced to 0.05 mmol/kg. The patient examinations revealed sufficient quality comparable with Gd-DTPA examinations despite of reduced dosage. In the volunteers Gd-BOPTA proved to be superior especially in the delineation of small pedal arteries which is important for surgical planning. These preliminary results demonstrate the potential of Gd-BOPTA to become a useful contrast agent for MRA. Its efficacy for this purpose has to be evaluated in future prospective studies.

Aortic Valve Stenosis↗
PubMed1998

[Calculation accuracy of volumes for evaluating dose-volume histograms. Comparison of various radiation planning systems].

BACKGROUND: Modern 3-dimensional treatment planning systems on the basis of sectional imaging allow the calculation of volumes for organs of interest. The aim of this study is to investigate systematically the accuracy of calculations of volumes by the use of a phantom for 4 different treatment planning systems. MATERIAL AND METHOD: The tests were done with a phantom with 5 cylindrical structures and 6 spherical shaped structures. After performing a CT-scan and reading the data into the planning systems the structures were contoured and the volumes were calculated in order to compare these values with the values calculated by mathematical equations. This was systematically done as a function of different parameters. RESULTS: Comparing different methods of contouring showed notable influence on the result. Parameters as number of calculation points or length of cylinders showed no significant differences. In summary, the mean deviations for cylinders were +7% for system A, -2% for B, -17% for C, and 0% for D. For larger spheres (radii between 5 and 2.5 cm) the mean deviations were -5% for A, +3% for B, +1% for C, and +5% for D. For smaller spheres (radii between 1.75 and 1.25 cm) the mean deviations were -14% for A, -2% for B, -10% for C, and -4% for D. CONCLUSION: Verifying results of planning systems is important for the daily routine, but it has to be taken into account, that small changes of the radius of a cylinder or sphere cause substantial volume changes. The differences are also caused by inaccuracies of the whole procedure, e.g., the CT study, the shape and dimensions of the cylinders and the spheres and the CT information and the delineariation of the structures.

Dose-Response Relationship, Radiation↗
PubMed1998

[Analysis of different application systems and CT-controlled planning variants in treatment of primary endometrial carcinomas. Is brachytherapy treatment of the entire uterus technically possible?].

BACKGROUND: Intracorporal brachytherapy is regarded as the definitive component of treatment for inoperable patients with endometrial carcinoma. Until now the whole uterus has been claimed to represent the target volume independent of individual tumor spread. The purpose of this work is to analyse the correlation between target volume and treated volume using different application- and planning procedures. PATIENTS AND METHODS: In a consecutive series of 10 patients with primary irradiated endometrial carcinoma we analyzed the correlation between target volume and treated volume using either standard 1-channel applicators or individual Heyman-applicators. Application of the ovoids was followed by a planning CT scan for all patients. Based on this, target volume (uterus volume) was estimated on a 3D-planning system. According to the measurable length of the uterus cavity we determined the corresponding standard 1-channel applicator and calculated the respectively treated volume. Estimating the advantages of an optimized treatment planning strategy for individual Heyman-applications were compared the treated volumes, which result from a standardized and optimized treatment planning procedure. RESULTS: The mean uterus volume was 180 cm3 (range 57 to 316 cm3). Asymmetric uterus configurations with longitudinal or sagittal side differences exceeding 1 cm were found in 40% of the cases. Using standard 1-channel applicators on average 47% (range 25 to 89%) of the uterus volume were enclosed by the treated volume compared to 70% for Heyman-applications. Differentiating these individual applications according to the variable treatment modality values of mean 66% (range 36 to 110%) for the standardized and 73% (range 48 to 95%) for the optimized treatment planning strategy were found. Moreover optimized planning modalities led to an improved coverage of the target volume in 5 out of 10 cases with an increase in volume of 20% on average (range 11 to 32%). In 3 cases changes of less than 5% were noticed (no improvement). In order to protect organs at risk treated volume had to be decreased in 2 cases for 19% and 40% respectively. CONCLUSIONS: Intracavitary brachytherapy of primary endometrial carcinoma was improved by individualized application- and planning procedures, which led to better adaptations of the treated volumes to the target volumes. Nevertheless a complete coverage--corresponding to the primary intent--was not possible. Individualized and optimized brachy-therapy must be performed according to the individual tumor spread and uterus configuration. Therefore, different applicators are required.

Adenocarcinoma↗
PubMed1998

Virtual cisternoscopy of intracranial vessels: a novel visualization technique using virtual reality.

This paper introduces a different visualization method which we call "virtual cisternoscopy" using 3D MRA data sets. Virtual cisternoscopy uses well known tools, such as perspective volume rendering (pVR), fly-through techniques, and interactive visualization and combines them to a new approach featuring motion to resolve spatial relationships of intracranial vessels and vascular malformations. With a dedicated flight protocol extraluminal topography of intracranial arteries was analyzed using pVR. For evaluation of difficult vascular malformations extraluminal views are necessary. Therefore, movies of pVR views were produced simulating virtual tracks of neurosurgical flexible endoscopes, by flying around the intracranial vessels and vascular malformations within the cisterns. Endoluminal views were acquired additionally for precise evaluation of cases with complex vessel topography. Two healthy volunteers and three patients were examined. Comparing MIP and pVR images relevant advantages of pVR were found, such as depth information, perspective, lighting, and color. In contrast to MIP and source images of the MRA data set, virtual cisternoscopy of an aneurysm of the left middle cerebral artery demonstrated clearly an early origin of an artery in the region of the aneurysm neck/sac. In this case only virtual cisternoscopy led to the correct therapeutical decision. In a newborn, the type of a vein of Galen aneurysmal malformation could only be evaluated reliably by means of virtual cisternoscopy. The third case of a patient with a clipped aneurysm was evaluated more easily with virtual cisternoscopy than with DSA. In conclusion, virtual cisternoscopy may improve the pretherapeutic visualization of intracranial vascular malformations.

Adult↗
PubMed1998

Functional MRI of the motor cortex using a conventional gradient system: comparison of FLASH and EPI techniques.

Gradient echo (GE) and echo planar imaging (EPI) techniques are two different approaches to functional MRI (fMRI). In contrast to GE sequences, the ultra short EPI technique facilitates fMRI experiments with high spatial and temporal resolution or mapping of the whole brain. Although it has become the method of choice for fMRI, EPI is generally restricted to modern scanners with a strong gradient system. The aim of our study was to evaluate the applicability of EPI for fMRI of the motor cortex using a 1.5 T scanner with a conventional gradient system of 10 mT/m (rise time: 1 ms). Therefore, EPI was compared with a well-established high-resolution fast low-angle shot (FLASH) technique (matrix size 1282). The FLASH technique was applied additionally with a 64(2) matrix size to exclude influences caused by different spatial resolution, because the EPI sequence was restricted to a 64(2) matrix size. A total of 35 healthy volunteers were included in this study. The task consisted of clenching and spreading of the right hand. FLASH and EPI techniques were compared regarding geometric distortions as well as qualitative and quantitative fMRI criteria: Mean signal increase between activation and rest and the area of activation were measured within the contralateral, ipsilateral, and supplementary motor cortex. The quality of subtraction images between activation and rest, as well as the quality of z-maps and time course within activated regions of interest, was evaluated visually. EPI revealed significant distortions of the anterior and posterior brain margins; lateral distortions (relevant for the motor cortex) could be neglected in most cases. The mean signal increase was significantly higher using FLASH 1282 compared to FLASH 64(2) and EPI 64(2), whereas the activated areas proved to be smaller in FLASH 1282 functional images. Both results can be explained by well-documented partial volume effects, caused by different voxel size. Similar quality of the subtraction images and of the time courses in different regions of interest were found for all techniques under investigation, but slightly reduced quality of z-map in FLASH 1282. Within the limits of reproducibility and measurement accuracy, the location of contralateral activation was similar using FLASH and EPI sequences. In conclusion, EPI proved to be a reliable technique for fMRI of the motor cortex, even on an MR scanner with a conventional gradient system.

Adult↗
PubMed1998

Dedicated head-neck coil in MR angiography of the supra-aortic arteries from the aortic arch to the circle of Willis.

PURPOSE: To evaluate the usefulness of a dedicated head-neck coil in preoperative imaging of the supra-aortic arteries. MATERIAL AND METHODS: Forty consecutive patients with suspected carotid artery stenosis underwent MR angiography (MRA). Using a dedicated head-neck coil, we made a complete evaluation of the supra-aortic arteries and graded the internal carotid artery (ICA) stenoses. MRA was performed at 1.5 T with: coronal 3D FISP from the aortic arch to the circle of Willis; transverse 2D FLASH and 3D TONE of the carotid bifurcation; transverse 3D TONE of the carotid siphon and the circle of Willis; and transverse 3D FISP of the aortic arch. I.a. digital subtraction angiography (DSA) was used as the reference. ICA stenoses of 70% and more at DSA (NASCET methodology) were regarded as severe. RESULTS: Severe ICA stenoses were detected with high sensitivity and specificity: 93% and 92% respectively for coronal 3D FISP; 90% and 85% respectively for transverse 2D FLASH; and 97% and 94% respectively for transverse 3D TONE. The carotid siphon and the intracranial ICA were best depicted by 3D TONE. None of the applied sequences gave a satisfactory visualization of the aortic arch or of the origins of the vertebral arteries. CONCLUSION: With the head-neck coil, the supra-aortic arteries (including the intracranial vessels) were visualized without the need to reposition the patient, but depiction of the aortic arch was not acceptable. The quantification of ICA stenoses was reliable.

Aged↗
PubMed1998

3D MRI of the membranous labyrinth. An age related comparison of MR findings in patients with labyrinthine fibrosis and in persons without inner ear symptoms.

PURPOSE: We compared MRI of the membranous labyrinth in patients with chronic non-neoplastic inner ear disease and MR signs of labyrinthine fibrosis and controls depending on their age, in order to establish whether there were any MR differences regarding patient age groups, control age groups and between the patients and controls themselves. MATERIALS AND METHODS: Clinical ENT examinations as well as a T2* weighted 3D CISS (Constructive Interference in Steady State) sequence with a slice thickness of 0.7 mm were performed. Our collective was subdivided as follows: 0-19 years (10 controls, 3 patients with chronic non-neoplastic inner ear disease), 20-49 years (55 controls, 8 patients), 50 years and older (40 controls, 22 patients). Detectability of labyrinthine structures (e.g. cochlea, vestibule, semicircular canals) and filling defects were evaluated. RESULTS: In the 3 age-groups of the control collective no significant differences were observed in the membranous labyrinth. However differences concerning labyrinthine detectability emerged between controls and patients in both the 20-49 years and 50 years and older age groups. In the patient collective the 3 age groups showed no significant discrepancy in the mean number of lesions. CONCLUSION: Filling defects of the membranous labyrinth on 3D CISS MR images are pathological even in older persons. We would therefore recommend high resolution T2* weighted MRI in the case of suspected labyrinthine fibrosis.

Adolescent↗
PubMed1998

Experiences with gadodiamide, a non-ionic contrast agent, in MRI of brain metastases.

29 patients suffering from brain metastases were studied with a single (0.1 mmol/kg body weight) and triple dose (0.3 mmol/kg) of gadodiamide, a non-ionic MR contrast agent. The study was performed using an extended imaging protocol with application of T1-weighted images in three orientations. Number of definite and suspected metastases, lesion contrast, edema delineation, and flow artefacts were evaluated. Most of the definite metastases were found in triple dose images. However, the total lesion number could only be determined by looking on all sequences as a whole. Furthermore, the number of suspected metastases could be significantly reduced with triple dose images, but once more all sequences were needed to do so. Flow artefacts were significantly increased by triple dose, whereby lesion contrast and edema delineation was considerably improved. The conclusion is that the combination of high dose application of the contrast agent and an optimized imaging protocol facilitates sufficient imaging of brain metastases. This is important for therapeutical considerations, because patients with more than 1-2 metastases will be treated primarily with radiation therapy instead of neurosurgery.

Brain Neoplasms↗
PubMed1997

MR angiography of the supra-aortic arteries using a dedicated head and neck coil: image quality and assessment of stenoses.

Our purpose was to evaluate a dedicated head and neck coil for demonstration of supra-aortic arteries with optimised magnetic resonance angiography techniques. We performed 47 examinations with a 1.5-T system. We used coronal 3D fast imaging with steady precession (FISP), axial 3D tilted optimised nonsaturating excitation (TONE) and 2D fast low-angle shot (FLASH) for the carotid bifurcation, axial 3D TONE with or without magnetisation transfer (MT) for intracranial arteries, and axial 3D FISP or TONE for the aortic arch. Evaluation included visual assessment of image quality and grading of stenoses near the carotid bifurcation; digital subtraction angiography was used as the reference method. Axial 3D TONE gave superior image quality at the carotid bifurcation, MT-TONE intracranially, and 3D FISP for the aortic arch vessels. Nevertheless, sensitivity and specificity for detection of significant stenoses were similar with coronal 3D FISP (96.3%, 94.0%), axial 3D TONE (92.6%, 92.5%) and axial 2D FLASH (96.3%, 86.6%). Image quality at the aortic arch needs further improvement.

Aged↗
PubMed1997

Fast spin-echo (FSE) and gradient- and spin-echo (GRASE) in fast MRI of the pelvis.

In this prospective study two different T2-weighted fast spin-echo (FSE) sequences and a gradient- and spin-echo (GRASE) sequence were compared in 20 consecutive patients undergoing clinical pelvic MR examinations. A GRASE and two FSE sequences were applied, whereby the FSE sequences differed from each other by altered echo spacings (15.0 and 22.5 ms) and T2 contrast. Quantitative image analysis included ROI evaluation of different S/N and C/N values. Visual image analysis was performed by two independent readers using a standardized score sheet for anatomic and pathologic findings. Overall image quality was significantly better in both FSE sequences. GRASE and FSE22.5 were superior in delineation of most of anatomic and pathologic structures due to intermediate to hypointense contrast behavior of pelvic fat compared to FSE15.0 in which fat was bright. Therefore, FSE15.0 was optimal for low intensity lesions. Short acquisition times of FSE and GRASE sequences allow application of two different techniques-fat hypointense respectively bright-for excellent lesion visualisation. This study demonstrates the usefulness of contrast manipulation in fast T2-weighted MRI techniques without special techniques, such as fat saturation.

Adipose Tissue↗
PubMed1997

[Artifacts in MR imaging of the temporomandibular joint caused by dental alloys: a phantom model study at T1.5].

PURPOSE: The influence of dental alloys on MRI of the temporomandibular joint was studied using a phantom model for this joint. METHODS: At 1,5 T, 15 dental alloys and 14 of their most important components were investigated acquiring sagittal (FOV: 150 mm) and transverse (FOV: 250 mm) T1-weighted SE images. In 11 cases, T1- and T2*-weighted FLASH images were measured additionally. The artifacts were assessed qualitatively as well as quantitatively, and the samples were subdivided into four artifact categories. RESULTS: Ag, Cu, Ga, In, Tl, Sn, Zn, amalgam, the precious alloys, the Au-Pd and Ag-Pd alloys showed no artifacts (category I). Minimal artifacts below 10 mm on transverse images (category II) were found for Cr, Pd, Pt and for the Ni-Cr alloy. Mn and the remaining non-precious alloys induced artifacts up to 30 mm (category III). Significant artifacts-more than 30 mm-(category IV) were caused by Ni-Cr and 18/8 wires and by Co, Fe, and Ni. T2*-weighted FLASH proved to be more susceptible for artifacts than T1-weighted SE and FLASH techniques. CONCLUSIONS: In contrast to dental alloys for fixed prosthodontics, Ni-Cr- or 18/8 wires used for orthodontic bands can influence not only the image quality, but also the diagnostic reliability of MRI of the temporomandibular joint.

Artifacts↗
PubMed1997

Diagnosis of liver metastases from colorectal adenocarcinoma. Comparison of spiral-CTAP combined with intravenous contrast-enhanced spiral-CT and SPIO-enhanced MR combined with plain MR imaging.

PURPOSE: The purpose of this study was to determine whether MR with and without SPIO (AMI-25) could replace spiral-CTAP in the staging of colorectal adenocarcinoma. MATERIAL AND METHODS: Thirty-five patients were studied prospectively by means of i.v. contrast-enhanced spiral-CT, spiral-CTAP, and MR of the liver. MR imaging was performed before and after infusion of AMI-25. Diagnoses were compared to intraoperative findings (n = 35) which included intraoperative ultrasound (n = 21), and follow-up CT (n = 18). RESULTS AND CONCLUSION: Fifteen patients were found to have a total number of 53 liver metastases and 43 benign lesions were detected. Evaluation was performed in four different ways: 1) i.v. contrast-enhanced spiral-CT; 2) i.v. contrast-enhanced spiral-CT + spiral-CTAP; 3) plain MR; 4) plain MR + SPIO-enhanced MR. I.v. contrast-enhanced spiral-CT, spiral-CTAP and SPIO-enhanced MR identified patients with liver metastases with equal sensitivity. However, owing to its significantly higher sensitivity, based on a lesion-by-lesion analysis, spiral-CTAP cannot be replaced by SPIO-enhanced MR in patients who are to undergo liver resection. A limitation in spiral-CTAP is its relatively low specificity.

Adenocarcinoma↗
PubMed1997

MRI of inner ear anatomy using 3D MP-RAGE and 3D CISS sequences.

The aim of this study was to compare contrast enhanced 3D MP-RAGE (magnetization prepared rapid gradient echo), unenhanced 3D MP-RAGE and 3D CISS (constructive interference in steady state) in the evaluation of anatomical detail of the inner ear and facial nerve. 60 persons with no abnormalities and no or non-specific symptoms were examined with MRI. All examinations were performed using a 1.5 T MR unit. The detectability of anatomical details was evaluated by agreement of three radiologists. Statistical evaluation of the results was achieved by the two-tailed Wilcoxon's test. In 86-95% of the cases, 3D CISS resulted in excellent visibility of the basal and second turn and apex of the cochlea, the vestibule and semicircular canals, as well as the nerves within the internal auditory canal. There was a significantly better visualization with CISS than with MP-RAGE. Detectability of the extrameatal facial nerve was best using contrast enhanced 3D MP-RAGE in 91-96% of the cases (labyrinthine segment 96.7%; geniculate ganglion 95%; tympanic segment 91.7%; vertical segment 95%). The detection of the meatal seventh nerve was best using CISS, whilst unenhanced MP-RAGE gave significantly better results than contrast enhanced MP-RAGE. These results suggest that unenhanced and contrast enhanced 3D MP-RAGE and 3D CISS sequences are complementary and not alternative MRI techniques. Both T1 and T2 weighted 3D MR imaging of the temporal bone is of advantage when compared with 2D MR sequences due to improved contrast, geometrical resolution and the possibility of adequate reconstruction of anatomical structures.

Adolescent↗
PubMed1997

MRI of inner ear and facial nerve pathology using 3D MP-RAGE and 3D CISS sequences.

The aim of this study was to evaluate 3D CISS, unenhanced 3D MP-RAGE and contrast enhanced 3D MP-RAGE for the diagnosis of neoplastic, vascular and inflammatory lesions of the cerebellopontine angle, the inner auditory canal, the labyrinth and the facial nerve 42 MR examinations were performed on a total of 38 patients (25 males, 13 females; aged 1-77 years, mean age 43 +/- 20 years) using a 1.5 T MR unit. A T2* weighted 3D CISS sequence (TR 14.65 ms, TE 21 ms, flip angle 65 degrees, voxel size 0.7 x 0.7 x 0.7 mm3) and a T1 weighted 3D MP-RAGE sequence (TR 12.5 ms, TE 5 ms, T1 300 ms, flip angle 15 degrees, voxel size 1.0 x 0.9 x 0.9 mm3) with and without contrast medium (gadolinium-DTPA, 0.1 mmol kg-1 body weight) were used. Results of contrast enhanced 3D MP-RAGE-pathological enhancement was found in the following lesions: schwannomas of the cerebellopontine angle (CPA) and the internal auditory canal (IAC), 4; schwannomas of the IAC, 7 and labyrinthine tumours, 3; posterior fossa lymphoma, 1; meatal meningioma, 1; acute labyrinthitis, 15 and neuritis of the seventh cranial nerve, 10. Results of 3D CISS-filling defects were found with the following lesions: schwannomas of the CPA, the IAC or labyrinth, 14; lymphoma, 1; meningioma, 1; labyrinthine fibrosis, 13 and scar in the IAC, 4. These results suggest that unenhanced and contrast enhanced 3D MP-RAGE and 3D CISS are complementary MR imaging modalities. T1 weighted 3D MP-RAGE is preferred to T1 weighted 2D (turbo) spin echo sequences because of the multiplanar reconstruction possibilities of 3D sequences, which are very useful in the case of the inner ear and facial nerve.

Acute Disease↗