Using curve-fitting of curvilinear features for assessing registration of clinical neuropathology with in vivo MRI.

Traditional neuropathological examination provides information about neurological disease or injury of a patient at a high-resolution level. Correlating this type of post mortem diagnosis with in vivo image data of the same patient acquired by non-invasive tomographic scans greatly complements the interpretation of any disease or injury. We present the validation of a registration method for correlating macroscopic pathological images with MR images of the same patient.

Deep sulcal landmarks provide an organizing framework for human cortical folding.

The folding pattern of the cerebral cortex and its relation to functional areas is notoriously variable and there is a need to identify more consistent 3-dimensional (3D) topographical cortical features. We analyzed magnetic resonance brain images of 96 normal adult human volunteers using automated 3D image analysis methods. We examined the deeper parts of the sulci because they generally show less interindividual variability than more superficial parts, especially in monozygotic twins, and deepest parts of primary sulci are the first to develop embryologically and change least as the cortex expands.

Investigating cortical variability using a generic gyral model.

In this paper, we present a systematic investigation of the variability of the human cortical folding using a generic gyral model (GGM). The GGM consists of a fixed number of vertices that can be registered non-linearly to an individual anatomy so that for each individual we have a clearly defined set of landmarks that is spread across the cortex. This allows us to obtain a regionalized estimation of intersubject variability.

Recall and recognition memory in amnesia: patients with hippocampal, medial temporal, temporal lobe or frontal pathology.

The relationship between recall and recognition memory impairments was examined in memory-disordered patients with either hippocampal, medial temporal, more widespread temporal lobe or frontal pathology. The Hirst [Hirst, W., Johnson, M.

Retrograde amnesia in patients with hippocampal, medial temporal, temporal lobe, or frontal pathology.

There is considerable controversy concerning the theoretical basis of retrograde amnesia (R.A.).

A construction of an averaged representation of human cortical gyri using non-linear principal component analysis.

Because of the complex shape of human cortical gyri and great variation between individuals, development of effective representation schemes which allow establishment of correspondence between individuals, extraction of average structure of a population, and co-registration has proved very difficult. We introduce an approach which extracts line representations of gyri at different depths from high resolution MRI, labels main gyri semi-automatically, and extracts a template from a population using non-linear principal component analysis. The method has been tested on data from 96 healthy human volunteers.

The origin of bovine spongiform encephalopathy: the human prion disease hypothesis.

The cause of the original case or cases of bovine spongiform encephalopathy (BSE) remains an enigma. Sheep scrapie or a previously undetected sporadic bovine transmissible spongiform encephalopathy (TSE) have long been considered as candidates, but no convincing evidence to support these proposals has come to light. We present a new theory, with three related hypotheses: (1) that BSE was acquired from a human TSE (prion disease); (2) that the route of infection was oral, through animal feed containing imported mammalian raw materials contaminated with human remains; and (3) that the origin was the Indian subcontinent, from which large amounts of mammalian material were imported during the relevant time period.

Integrating watersheds and critical point analysis for object detection in discrete 2D images.

This paper presents an improved method for the detection of "significant" low-level objects in medical images. The method overcomes topological problems where multiple redundant saddle points are detected in digital images. Information derived from watershed regions is used to select and refine saddle points in the discrete domain and to construct the watersheds and watercourses (ridges and valleys).

Retrograde amnesia and the volume of critical brain structures.

There are many controversies concerning the structural basis of retrograde amnesia (RA). One view is that memories are held briefly within a medial temporal store ("hippocampal complex") before being "consolidated" or reorganised within temporal neocortex and/or networks more widely distributed within the cerebral cortex. An alternative view is that the medial temporal lobes are always involved in the storage and retrieval (reactivation) of autobiographical memories (multiple trace theory).

FDG-PET findings in the Wernicke-Korsakoff syndrome.

This study reports FDG-PET findings in Wernicke-Korsakoff patients. Twelve patients suffering amnesia arising from the Korsakoff syndrome were compared with 10 control subjects without alcohol-related disability. Subjects received [18F]-fluorodeoxyglucose (FDG-PET) imaging as well as neuropsychological assessment and high-resolution MR imaging with volumetric analysis.

Correlation of intra-operative duplex findings during carotid endarterectomy with neurological events and recurrent stenosis at one year.

Objectives: Carotid endarterectomy has been used to treat both asymptomatic and symptomatic disease and this has meant that recurrent stenosis and its effect on late stroke risk have become increasingly important. In this study we compared anatomical defects and residual stenosis identified intra-operatively with recurrent stenosis and new symptoms developing in the first year after surgery.

Design, Materials & Methods: Two hundred and forty-four consecutive patients undergoing carotid endarterectomy were studied prospectively.

MRI of Creutzfeldt-Jakob disease: imaging features and recommended MRI protocol.

Creutzfeldt-Jakob Disease (CJD) is a rare, progressive and invariably fatal neurodegenerative disease characterized by specific histopathological features. Of the four subtypes of CJD described, the commonest is sporadic CJD (sCJD). More recently, a new clinically distinct form of the disease affecting younger patients, known as variant CJD (vCJD), has been identified, and this has been causally linked to the bovine spongiform encephalopathy (BSE) agent in cattle.

Automated segmentation of multiple sclerosis lesions by model outlier detection.

This paper presents a fully automated algorithm for segmentation of multiple sclerosis (MS) lesions from multispectral magnetic resonance (MR) images. The method performs intensity-based tissue classification using a stochastic model for normal brain images and simultaneously detects MS lesions as outliers that are not well explained by the model. It corrects for MR field inhomogeneities, estimates tissue-specific intensity models from the data itself, and incorporates contextual information in the classification using a Markov random field.

Structural MRI volumetric analysis in patients with organic amnesia, 2: correlations with anterograde memory and executive tests in 40 patients.

Background: Cognitive-MRI correlations have often been studied in disorders in which there are multiple cognitive deficits and widespread cortical atrophy, such as Alzheimer's dementia. In such circumstances, the interpretation of any single cognitive-structural correlation is equivocal. Only by measuring differing cognitive functions and a wide range of brain structures in patients with a varying distribution of lesions or atrophy can specific brain-cognitive relations be determined in neurological disorder.

Structural MRI volumetric analysis in patients with organic amnesia, 1: methods and comparative findings across diagnostic groups.

Background: If they are to be replicable, MRI volume measurements require explicit definitions of structures and of criteria for delineating these structures on MRI. Previously published volumes in healthy subjects show considerable differences in measurements across different studies, including a fourfold variation in estimates of hippocampal volume. Previous neuroimaging reports in patients with Korsakoff syndrome have generally found widespread or non-specific change, whereas in patients with herpes encephalitis the extent of pathological involvement reported beyond the temporal lobes has varied.

Exploring the discrimination power of the time domain for segmentation and characterization of active lesions in serial MR data.

This paper presents a new method for the automatic segmentation and characterization of object changes in time series of three-dimensional data sets. The technique was inspired by procedures developed for analysis of functional MRI data sets. After precise registration of serial volume data sets to 4-D data, we applied a time series analysis taking into account the characteristic time function of variable lesions.

The pulvinar sign on magnetic resonance imaging in variant Creutzfeldt-Jakob disease.

Background: There is a need for an accurate non-invasive diagnostic test for variant Creutzfeldt-Jakob disease (vCJD). We investigated the sensitivity and specificity of bilateral pulvinar high signal on magnetic resonance imaging (MRI) for the diagnosis of vCJD.

Methods: MRI from patients with vCJD and controls (patients with suspected CJD) were analysed.

Cost-effective carotid endarterectomy.

Background: Although carotid endarterectomy is increasing in the UK, there is evidence that the procedure is still underused. Methods of reducing cost in a single vascular unit have been assessed using a continuous audit including outcome measures.

Methods: A consecutive series of 333 patients admitted over 7 years under a single consultant surgeon were studied.

A geometry-and intensity-based partial volume correction for MRI volumetric studies.

Segmentation of objects of interest in magnetic resonance imaging is a necessary procedure for volumetric calculations. However, these direct measurements tend to be inaccurate due to the intrinsic MRI partial volume effects. In this paper, a general method for correcting these effects based on the geometry and grey level intensity of the segmented objects is presented.

The changing indications for carotid endarterectomy in the UK.

In early series the majority of carotid endarterectomies were performed in patients with amaurosis fugax (AFx) or transient ischaemic attacks (TIAs) who were thought to have atheromatous ulcers of the carotid bifurcation or the internal carotid artery (ICA). The degree of stenosis was considered to be of secondary importance. We compared our own data with two British series undertaken in the early and late 80s/early 90s.

New variant Creutzfeldt-Jakob disease: neurological features and diagnostic tests.

Background: In April, 1996, ten cases of Creutzfeldt-Jakob disease (CJD) with an apparently new clinicopathological phenotype were published and it was suggested that these new variant cases (nvCJD) might be causally linked to bovine spongiform encephalopathy (BSE). There have now been 21 cases of nvCJD in the UK and one case in France. We report clinical features and diagnostic test results of the first 14 cases of nvCJD in the UK.

The measurement of internal carotid artery stenosis: comparison of duplex with digital subtraction angiography.

Objectives: To compare the subjective (eyeballed) method for measuring internal carotid artery (ICA) stenosis by non-selective intra-arterial digital subtraction angiography (IA-DSA) with objective and duplex methods.

Design: Retrospective study.

Materials And Methods: Fifty-three consecutive patients underwent IA-DSA prior to carotid endarterectomy providing 103 carotid angiograms.

Morphological and hemodynamic assessments of carotid stenosis using quantitative digital subtraction angiography.

Background And Purpose: Digital angiography is the best established tool for assessing atheromatous disease of extracranial blood vessels. Advances in computer technology have now made it possible and practicable to extract quantitative information (length, width, cross-sectional area, and flow velocity) from good-quality clinical angiograms, allowing calculation of volume flow and pressure gradient. The technique of quantitative angiography (QA) is used for assessing coronary artery disease, but to date there has been no clinical application in patients with cerebrovascular disease.

Development and preliminary evaluation of VISLAN, a surgical planning and guidance system using intra-operative video imaging.

VISLAN is an integrated neurosurgical planning and guidance system. New segmentation and rendering techniques have been incorporated. A stereo video system is used intra-operatively and fulfils four roles.