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PubMed1997

[Harlequin syndrome].

Harlequin syndrome is an autonomic syndrome of heat, emotion and exercise induced flushing and sweating limited to one side of the face in combination with impairment of sweating and flushing on the contralateral side, Two women aged 32 and 39 years displayed this syndrome. In one patient no other neurological symptoms were found; MRI of cervicothoracic spine failed to disclose a structural lesion. The second patient had four years before presented with a Horner's syndrome on the contralateral side, where MRI now disclosed a tumour located in the paravertebral thoracic region at the apex of the lung.

Adult↗
PubMed2004

Quantitative SPECT leads to improved performance in discrimination tasks related to prodromal Alzheimer's disease.

UNLABELLED: We investigated the impact of the quantitation and reconstruction protocol on clinical tasks. The performance of standard clinical reconstruction procedures in discrimination tasks related to the diagnosis of prodromal Alzheimer's disease (AD) was compared with the performance of a quantitative approach incorporating improved corrections for scatter, attenuation, intrinsic spatial resolution, and distance-dependent spatial resolution. METHODS: Seventeen normal controls (normal group), 56 subjects who did not have dementia, who did have memory problems, but who did not develop AD within 5 y of follow-up (questionable group), and 27 subjects who did not have dementia, who did have memory problems, and who did develop AD over the follow-up period (converter group) were considered in this study. (99m)Tc-hexamethylpropyleneamine oxime SPECT and MRI studies were performed for each subject at baseline. The standard quantitation protocol (STD), routinely used in our clinic, consisted of Compton window scatter correction followed by filtered backprojection with attenuation correction using a uniform attenuation map. In the improved quantitative approach (QUAN), projections were corrected for scatter by use of a general spectral method and reconstructed by use of ordered-subset(s) expectation maximization, incorporating corrections for collimator response and attenuation using both a uniform attenuation map (QUANunif) and a nonuniform attenuation map (QUANnonunif). Mean SPECT activity concentration and MRI volume were estimated for 7 structures: rostral anterior cingulate gyrus, caudal anterior cingulate gyrus, posterior cingulate gyrus, hippocampus, basal forebrain, amygdala, and the banks of the superior temporal sulcus. Data were analyzed by pairwise discriminant analysis, and performance in binary group discrimination was measured by correlated receiver-operating-characteristic analysis. RESULTS: The use of QUANnonunif yielded a small but systematic improvement in discrimination accuracy for normal versus converter groups (accuracy or area under the receiver-operating-characteristic curve [Az], 0.965), normal versus questionable groups (Az, 0.973), and questionable versus converter groups (Az, 0.881) compared with the results obtained with QUANunif (Az, 0.955, 0.962, and 0.866, respectively). Discrimination performance was significantly lower (P < 0.05) with STD than with QUAN in all 3 tasks (Az with STD, 0.906, 0.878, and 0.768, respectively). MRI volume estimation led to a lower overall performance in all 3 tasks than did QUANnonunif (Az with MRI, 0.947, 0.917, and 0.872, respectively). CONCLUSION: Improved quantitative image reconstruction with accurate compensation for scatter, attenuation, and variable collimator response led to significantly better performance in discrimination tasks related to the diagnosis of prodromal AD than did standard clinical reconstruction procedures. The use of a nonuniform brain attenuation map yields a small improvement in discrimination accuracy.

Aged↗
PubMed1991

Magnetic resonance imaging study of the structure of the yolk in the developing avian egg.

Magnetic resonance imaging (MRI) techniques were used to study the morphology of the latebra and concentric rings seen in the yolk of White Leghorn eggs during development of the avian embryo. Previous studies of the macroscopic structure of avian yolk have revealed the latebra, a vase-shaped structure beneath the blastoderm composed of white yolk. The bulbous portion in the center of the yolk is termed the body of the latebra. The thinner portion extending toward the blastoderm is referred to as the neck of the latebra. As the neck of the latebra approaches the blastoderm, it flares out to become the nucleus of Pander. The remainder of the yolk often features alternating concentric layers of white and yellow yolk. These layers, which appear as rings in sections, are thought to represent the daily accumulation of yolk during oogenesis. In this study eggs were imaged with a single slice spin echo sequence using MRI parameters that maximized the visualization of the latebra and concentric rings in the egg yolk. Some experiments were conducted for 2 to 3 day periods with eggs kept in the bore of the magnet using a small incubator that was constructed using a temperature-controlled water pump. The concentric rings of the yolk and the body of the latebra flatten and become more elliptical during development. The neck of the latebra becomes shorter and disappears around the 7th day of incubation. The body of the latebra starts to become incorporated into the embryo at about the 7th day of incubation and usually disappears by the 13th day. The concentric rings are no longer visible as distinct entities at this time. Histochemical procedures carried out as a result of MRI findings indicate that the latebra is an iron-rich structure.

Animals↗
PubMed2003

Using magnetic resonance imaging and diffusion tensor imaging to assess brain damage in alcoholics.

Brain imaging using conventional magnetic resonance imaging (MRI) has revealed that several brain structures in people with a history of chronic alcohol dependence are smaller in volume than the same brain structures in nonalcoholic control subjects. Areas that are particularly affected are the frontal lobes, which are involved in reasoning, judgment, and problem solving. Older people are especially vulnerable to the damaging effects of alcohol. It is unclear whether women show consistently more vulnerability to these changes in the brain than men do. In general, alcoholics evaluated before and after a period of abstinence show some recovery of tissue volume, whereas alcoholics evaluated again after continued drinking show further reductions in brain tissue volume. A new MR technique called diffusion tensor imaging (DTI) can aid in detecting the degradation of fibers (i.e., white matter) that carry information between brain cells (i.e., gray matter). With DTI, researchers studying alcoholics have been able to detect abnormalities in white matter not visible with conventional MRI. Ultimately DTI may be useful in elucidating the mechanisms that underlie macrostructural and functional brain changes seen with abstinence and relapse.

Alcoholism↗
PubMed2005

Posterior tibial tendon insufficiency: which ligaments are involved?

BACKGROUND: The pathology manifested in posterior tibial tendon insufficiency (PTTI) is not limited to the posterior tibial tendon. The association of ligament failure with deformity has been discussed in numerous publications, but extensive documentation of the structures involved has not been performed. The purpose of this observational study was to identify the pattern of ligament involvement using standardized, high-resolution magnetic resonance imaging (MRI) in a series of 31 consecutive patients diagnosed with PTTI compared to an age matched control group without PTTI. METHOD: The structures evaluated by MRI were the posterior tibial tendon, superomedial and inferomedial components of the spring ligament complex, talocalcaneal interosseous ligament, long and short plantar ligaments, plantar fascia, deltoid ligament, plantar naviculocuneiform ligament, and tarsometatarsal ligaments. Structural derangement was graded on a five-part scale (0 to IV) with level 0 being normal and level IV indicating a tear of more than 50% of the cross-sectional area of the ligament. Standard flatfoot measurements taken from preoperative plain standing radiographs were correlated with the MRI grading system. RESULTS: Statistically significant differences in frequency of pathology in the PTTI group and controls were found for the superomedial calcaneonavicular ligament (p < 0.0001), inferomedial calcaneonavicular ligament (p < 0.0001), interosseous ligament (p = 0.0009), anterior component of the superficial deltoid (p < 0.0001), plantar metatarsal ligaments (p = 0.0002) and plantar naviculocuneiform ligament (p = 0.0006). The ligaments with the most severe involvement were the spring ligament complex (superomedial and inferomedial calcaneonavicular ligaments) and the talocalcaneal interosseous ligament. CONCLUSION: Ligament involvement is extensive in PTTI, and the spring ligament complex is the most frequently affected. Because ligament pathology in PTTI is nearly as common as posterior tibial tendinopathy, treatment should seek to protect or prevent progressive failure of these ligaments.

Adult↗
PubMed2005

Reliability of atlas-derived coordinates in deep brain stimulation.

BACKGROUND: In deep brain stimulation the way to define and localize the optimal target for the individual patient is still under debate. The objective of our study was to investigate the reliability of atlas derived data by comparing them with direct targeting on MR images. METHOD: We investigated 28 STN targets in 14 volunteers. The stereotactic coordinates of the dorso-lateral subthalamic nucleus (STN), were determined in 5 different ways for both STNs of each individual volunteer: 1. directly, on axial T2WI spin echo slices, 2. directly, on coronal T2WI spin echo slices and after fusion of data sets: 3. indirectly, on an axial atlas plate, 4. indirectly, on a coronal atlas plate, 5. indirectly, 12 mm lateral, 3 mm posterior and 3 mm inferior to mid-AC-PC. FINDINGS: The differences between MRI derived targets on axial vs. coronal slices were not statistically significant. After detection of the atlas derived targets the resulting x-coordinates were found more lateral than after direct detection on both, axial and coronal T2-weighted images (p < 0.001). On axial images y-coordinates were located more anterior (p = 0.240) on atlas derived targets and more posterior when target localizations were compared on coronal slices (p < 0.001). z-Coordinates were more superior after atlas targeting compared to MRI targeting (p < 0.001). Differences up to 6.21 mm occurred. CONCLUSIONS: Despite the limitations concerning image distortions and slice thickness, direct target planning on MRI, regarding our results, is more reliable than targeting solely based on atlas derived data. Only MRI gives us detailed information about the individual configurations of central structures in every single patient. However, targets, which are not detectable on MRI like the nucleus ventralis intermedius have to be planned using stereotactic atlas information. In these cases intra-operative micro-electrode recording might help to better define the target region.

Adult↗
PubMed1997

The diagnostic value of magnetic resonance imaging and technetium 99m-HMPAO single-photon-emission computed tomography for the diagnosis of Alzheimer disease in a community-dwelling elderly population.

The objective of this study was to assess the diagnostic value for Alzheimer disease (AD) of single-photon-emission computed tomography (SPECT) and magnetic resonance imaging (MRI), separately and in combination. The study was part of a two-stage population-based study of mental functioning among noninstitutionalized 65-to 85-year-olds living in Amsterdam, The Netherlands. Participants (n = 51) were randomly selected within strata of cognitive function to obtain a sample of AD patients (n = 10) and clinically normal subjects (n = 41), of whom 22 displayed some cognitive impairment and fulfilled criteria for "minimal dementia" according to the Cambridge Examination for Mental Disorders of the Elderly. Coronal T1-weighted MRI was used to visualize the medial temporal lobe. Medial temporal lobe atrophy (MTA) was assessed qualitatively on a 0-4 scale. Regional cerebral blood flow on SPECT was assessed with the use of technetium 99m-HMPAO in three manually drawn regions of interest (frontal, parietal, and temporoparietal). Ratios were calculated by using the cerebellum as the reference area. MTA differed significantly between AD patients and clinically normal subjects (p = 0.0009), with sensitivity for AD of 70% and a specificity of 76%. None of the three SPECT ratios differed between normal and AD subjects. The temporoparietal/cerebellar ratio had a sensitivity of 30% and a specificity of 71% as a cutoff of 0.76. When both tests were positive the combined sensitivity was low (20%), but the false-positive rate was also very low (5%). A negative result on MRI or any SPECT ratio yielded a high specificity (93%-98%) but also a high false-negative rate (60-80%). Adding SPECT to MRI seems useful only if a diagnosis of AD is suspected clinically and confirmation is needed. When the clinical probability that AD is absent is high, normal results on either MRI or SPECT may confirm this notion. Given the fact that structural imaging should be performed in a clinical workup for dementia, using MRI only would be the most cost-effective approach.

Aged↗
PubMed2006

Magnetic resonance microscopy of the equine hoof wall: a study of resolution and potential.

REASONS FOR PERFORMING STUDY: Obtaining magnetic resonance images of the inner hoof wall tissue at the microscopic level would enable early accurate diagnosis of laminitis and therefore more effective therapy. OBJECTIVES: To optimise magnetic resonance imaging (MRI) parameters in order to obtain the highest possible resolution of the structures beneath the equine hoof wall. METHODS: Magnetic resonance microscopy (MRM) was performed in front feet from 6 cadaver horses using T2-weighted fast spin echo (FSE-T2), and T1-weighted gradient echo (GRE-T1) sequences. RESULTS: In T2 weighted FSE images most of the stratum medium showed no signal, however the coronary, terminal and sole papillae were visible. The stratum lamellatum was clearly visible and primary epidermal lamellae could be differentiated from dermal lamellae. CONCLUSION: Most structures beneath the hoof wall were differentiated. Conventional scanners for diagnostic MRI in horses are low or high field. However this study used ultra-high field scanners currently not available for clinical use. Signal-to-noise ratio (S/N) increases as a function of field strength. An increase of spatial resolution of the image results in a decreased S/N. S/N can also be improved with better coils and the resolution of high field MRI scanners will increase as technology develops and surface array coils become more readily available. POTENTIAL RELEVANCE: Although MR images with microscopic resolution were obtained ex vivo, this study demonstrates the potential for detection of lamellar pathology as it occurs. Early recognition of the development of laminitis to instigate effective therapy at an earlier stage and may improve the outcome for laminitic horses. Clinical MR is now readily available at 3 T, while 4 T, 7 T and 9 T systems are being used for human whole body applications.

Abattoirs↗
PubMed2004

Bilateral epidermoid cysts of the testis: sonographic and MRI findings.

Epidermoid cysts of the testis are rare benign lesions, without malignant potential, that can be managed conservatively with cyst enucleation and testis-sparing surgery. Bilateral epidermoid cysts in the testes have been reported very infrequently. We report the sonographic and MRI findings in a patient who presented with a palpable nodule in only 1 testis, but in whom sonography showed bilateral lesions. On sonography, the cysts had an internal "onion-ring" structure; color Doppler signals were absent. On MRI, the cysts had a laminated appearance, with alternating low- and high-signal-intensity areas on T2-weighted images. These imaging findings and the negative results of laboratory tests for tumor markers suggested the correct diagnosis, and testis-sparing surgery could be performed.

Adult↗
PubMed2006

EEG and MRI correlates of mild cognitive impairment and Alzheimer's disease.

OBJECTIVE: To investigate whether cognitive function in the spectrum of normal aging to Alzheimer's disease is better reflected in MRI or EEG measures, or a combination of both. METHODS: Cognitive functions were tested in 33 elderly subjects: 10 with probable Alzheimer's disease, 11 with mild cognitive impairment and 12 controls. Structural brain parameters were derived from conventional MRI and a quantitative MR technique called magnetization transfer imaging. The EEG provided measures of brain function. We performed multiple linear regression analyses to relate EEG and MRI parameters to global cognition, memory, language and psychomotor speed. RESULTS: The model showed EEG alpha reactivity during eyes open to be the primary factor associated with global cognition, memory and language skills. Brain atrophy was the primary factor associated with psychomotor speed. Furthermore, EEG alpha reactivity during eyes open explained significant additional variability in psychomotor speed. CONCLUSION: EEG and MRI are each associated with different aspects of cognitive function and complement each other in their relations to psychomotor speed.

Aged↗
PubMed1991

The role of MRI in cerebral infarction.

Although nuclear magnetic resonance has existed since the 1940s and was used extensively in chemistry labs for molecular structural determination, it was not until the 1970s that the possibility for magnetic resonance imaging (MRI) was realized. It is only in the last few years that the great potential of MRI to visualize the brain, joints and several other structures has been recognized. This article discusses some basic pathophysiology of cerebral ischemia as it relates to MRI and focuses on some of the advantages and disadvantages of MRI in visualizing and studying many of the resulting lesions.

Brain↗
PubMed2006

Accurate magnetic resonance imaging of atherosclerotic plaques: change future strategies for the diagnosis and therapy of atherosclerotic disease.

In recent years, magnetic resonance imaging (MRI) have been developed to image atherosclerosis and is emerging as a useful tool to assess the burden of atherosclerosis, whereas the potential influence on the diagnosis and therapy of atherosclerotic disease have not been fully determined. MRI allows for three-dimensional evaluation of vascular structures and outstanding depiction of various components of the atherosclerotic plaque. The self-contained intravascular MRI probe appears to hold promise in the identification of high-risk coronary and peripheral atherosclerotic lesions. Molecular and targeted contrast MRI can offer exciting possibilities of direct visualization of biologic processes within atherosclerotic tissue. The addition of quantitative hydrogen 1 magnetic resonance spectroscopy and diffusion weighted imaging within atherosclerotic plaques can provide important data on the biological activity of potentially vulnerable lesions. Therefore, we hypothesized that accurate magnetic resonance imaging of atherosclerotic plaques maybe further affect and change future strategies for the diagnosis and therapy of atherosclerotic disease.

Atherosclerosis↗
PubMed2004

Anterior cingulate, gyrus rectus, and orbitofrontal abnormalities in elderly depressed patients: an MRI-based parcellation of the prefrontal cortex.

OBJECTIVE: To examine structural abnormalities in subregions of the prefrontal cortex in elderly patients with depression, the authors explored differences in gray matter, white matter, and CSF volumes by applying a parcellation method based on magnetic resonance imaging (MRI). METHOD: Twenty-four elderly patients with major depression and 19 group-matched comparison subjects were studied with high-resolution MRI. Cortical surface extraction, tissue segmentation, and cortical parcellation methods were applied to obtain volume measures of gray matter, white matter, and CSF in seven prefrontal subregions: the anterior cingulate, gyrus rectus, orbitofrontal cortex, precentral gyrus, superior frontal cortex, middle frontal cortex, and inferior frontal cortex. RESULTS: Highly significant bilateral volume reductions in gray matter were observed in the anterior cingulate, the gyrus rectus, and the orbitofrontal cortex. Depressed patients also exhibited significant bilateral white matter volume reductions and significant CSF volume increases in the anterior cingulate and the gyrus rectus. Finally, the depressed group showed significant CSF volume reductions in the orbitofrontal cortex relative to the comparison subjects. None of the other regions examined revealed significant structural abnormalities. CONCLUSIONS: The prominent bilateral gray matter deficits in the anterior cingulate and the gyrus rectus as well as the orbitofrontal cortex may reflect disease-specific modifications of elderly depression. The differential pattern of abnormalities detected in the white matter and CSF compartments imply that distinct etiopathological mechanisms might underlie the structural cortical changes in these regions.

Aged↗
PubMed1995

Organ- and non-organ-specific auto-antibodies in children with hypopituitarism on growth hormone therapy.

UNLABELLED: Serum non-organ-specific antibodies (NOSA) against nuclear, mitochondrial (AMA), smooth muscle, liver/kidney microsomal (LKM), reticulin, ribosomal, and organ-specific antibodies (OSA) against pituitary gland, gonads (testis, ovary) adrenal cortex, thyroid (thyroglobulin and microsomal), pancreas islet cells, gastric parietal cells and intestinal epithelial cells were evaluated in 45 patients with hypopituitarism (mean age 12.4 +/- 4.0 years). In 22 of them, 9 with isolated growth hormone (GH) deficiency (IGHD) and 13 with multiple pituitary hormone deficiency, MRI showed anterior pituitary hypoplasia with structural stalk abnormality and ectopic posterior pituitary. Twelve had isolated small anterior pituitary and IGHD and 11 had normal morphology of pituitary gland and IGHD. Controls were healthy age-sex-matched subjects. Thyroid antibodies were detected by a passive haemagglutination test while indirect immunofluorescence was used for the others. The auto-antibodies were found in 7/45 asymptomatic patients, a frequency not significantly different from that in controls; 5 were type NOSA and 2 type OSA. Pituitary antibodies were positive in 1 girl with IGHD and normal pituitary morphology. One girl developed hyperthyroidism during the follow up. Autoantibodies were equally distributed between the three groups and the frequency was not dissimilar from that in controls; this suggests that these patients are not at a higher risk of developing auto-immune disease, at least during the first two decades. CONCLUSION: Pituitary insufficiency in children with different MRI features seems unlikely to be secondary to an auto-immune process.

Adolescent↗
PubMed2005

[MR imaging in mental retardation].

Mental retardation is considered idiopathic or not otherwise specified when no etiological diagnosis can be identified in spite of comprehensive history, physical examination and metabolic or genetic investigations. In such cases, brain MRI is indicated for patients with abnormal head size or shape, craniofacial malformation, somatic anomalies, neurocutaneous findings, seizures, focal neurological findings or behavioral and/or developmental problems. Brain anomalies are now considered a main category for the etiology of mental retardation. MRI evaluation should include axial images of the entire brain, sagittal images through the midline structures, and coronal images of the posterior fossa or entire brain. MRI allows detection of major and or minor cerebral anomalies or malformations, sometimes multiple. In the literature, the most frequently involved structures include: 1/ corpus callosum (hypoplasia, short corpus callosum and verticalized splenium), 2/ septum pellucidum (cavum septum pellucidum or cavum vergae), 3/ ventricles (ventriculomegaly), 4/ cerebral cortex (cortical dysplasia), 5/ cerebellum (hypoplasia), and 6/ extra-axial CSF spaces (enlargement). In our patient population, dysplasia involving the cerebellum and vermis have been identified, a finding that has not yet been described in the literature. MRI allows detection of multiple minor morphological anomalies. Most have classically been considered as normal variants but they may in fact be markers of cerebral dysgenesis and are currently the only anomaly detected in the work-up of patients with mental retardation. Their role in the pathogenesis of mental retardation is under evaluation.

Adolescent↗
PubMed2005

Insights into the acute cerebral metabolic changes associated with childhood diabetes.

AIMS: Type 1 diabetes is a prevalent chronic disease in childhood with the commonest single cause of death being cerebral oedema in the context of diabetic ketoacidosis (DKA). The nature of the alterations in cerebral metabolism that may result in vulnerability to neuronal injury remains unknown. The aim of this study was to analyse the magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) brain data from eight children with diabetes following acute presentation with hyperglycaemia with or without ketoacidosis, to determine the nature and timing of any alterations in cerebral structure and metabolism. METHODS: This study used MRI and MRS to investigate regional cerebral abnormalities in a small series of diabetic patients with and without DKA. Changes were compared with the clinical and biochemical features of the patients studied. RESULTS: Our small series of patients all demonstrated abnormal signal changes in the frontal region on fluid attenuated inversion recovery (FLAIR) MR imaging, suggestive of oedema, and spectroscopic abnormalities of increased taurine, myoinositol and glucose levels. The MR abnormalities varied in severity but did not correlate with any clinical or biochemical parameters. CONCLUSIONS: These changes indicate that many diabetic children, particularly at presentation, may have alterations in cerebral metabolism with implications for the pathogenesis and treatment of the cerebral complications of DKA. In addition, our findings suggest that increased taurine may be one of the important differentiating factors in the response of the brain of diabetic children to DKA that may reflect an increase in their vulnerability to cerebral oedema compared with diabetic adults.

Adolescent↗
PubMed2006

Tracking atrophy progression in familial Alzheimer's disease: a serial MRI study.

BACKGROUND: Serial MRI scanning of autosomal dominant mutation carriers for Alzheimer's disease provides an opportunity to track changes that could predate symptoms or clinical diagnosis of the disease. We used hierarchical modelling to assess how hippocampal and whole-brain volumes change as familial Alzheimer's disease progresses from the presymptomatic stage through to diagnosis. METHODS: Nine mutation carriers had serial clinical assessments and volumetric MRI scans (41 scans: range 3-8 per patient) at different clinical stages (presymptomatic, mild cognitive impairment, or clinical Alzheimer's disease). 25 healthy controls had serial scanning (54 scans: range 2-4 per patient) for comparison. We measured whole brain and total hippocampal volumes using semi-automated techniques, and adjusted for total intracranial volume. Hierarchical models were developed to estimate differences in volume and atrophy rate between mutation carriers and controls in relation to when the disease was clinically diagnosed. FINDINGS: Mutation carriers had significantly increased hippocampal and whole-brain atrophy rates compared with controls and these differences increased with time. Differences in hippocampal and whole-brain atrophy rates between controls and mutation carriers were evident 5.5 and 3.5 years, respectively, before diagnosis of Alzheimer's disease. At a cross-sectional level, differences in mean hippocampal volume between mutation carriers and controls became significant 3 years before clinical diagnosis, whereas differences in mean brain volumes became significant only 1 year before diagnosis. INTERPRETATION: Structural changes can be seen on MRI scans that predate the clinical onset of familial Alzheimer's disease. Longitudinal measures of atrophy rates can identify differences between mutation carriers and controls 2-3 years earlier than cross-sectional volumetric measures.

Adult↗
PubMed1999

[Imaging of the cerebello-pontine angle and skull base].

Lesions of the internal auditory meatus, cerebello-pontine angle and skull base have benefited greatly from the progress made in imaging techniques. There are now three methods of examination at our disposal. MRI scan is the primary method of choice, and includes T1 spin echo sequences without and with the injection of contrast, and the T2-weighted sequence (with spin echo or gradient echo CISS-3DFT); other sequences, such as angio-MRI and FLAIR, are used more rarely. CTscanning is complementary to MRI, but gives a better definition of bony structures. Arteriography is more rarely indicated. Imaging usually allows a diagnosis of the type of lesion encountered. The typical features on MRI and CT scan of the various pathological lesions of the internal auditory meatus, cerebello-pontine angle and skull base are discussed, together with the fact that by far the commonest among them is the vestibular neuroma.

Cerebellopontine Angle↗