Gareth J. F. Jones

Imaging of amyloid β in Alzheimer's disease with 18F-BAY94-9172, a novel PET tracer: proof of mechanism

BACKGROUND Amyloid-beta (Abeta) plaque formation is a hallmark of Alzheimers disease (AD) and precedes the onset of dementia. Abeta imaging should allow earlier diagnosis, but clinical application is hindered by the short decay half-life of current Abeta-specific ligands. (18)F-BAY94-9172 is an Abeta ligand that, due to the half-life of (18)F, is suitable for clinical use. We thus studied the effectiveness of this ligand in identifying patients with AD. METHODS 15 patients with mild AD, 15 healthy elderly controls, and five individuals with frontotemporal lobar degeneration (FTLD) were studied. (18)F-BAY94-9172 binding was quantified by use of the standardised uptake value ratio (SUVR), which was calculated for the neocortex by use of the cerebellum as reference region. SUVR images were visually rated as normal or AD. FINDINGS (18)F-BAY94-9172 binding matched the reported post-mortem distribution of Abeta plaques. All AD patients showed widespread neocortical binding, which was greater in the precuneus/posterior cingulate and frontal cortex than in the lateral temporal and parietal cortex. There was relative sparing of sensorimotor, occipital, and medial temporal cortex. Healthy controls and FTLD patients showed only white-matter binding, although three controls and one FTLD patient had mild uptake in frontal and precuneus cortex. At 90-120 min after injection, higher neocortical SUVR was observed in AD patients (2.0 [SD 0.3]) than in healthy controls (1.3 [SD 0.2]; p<0.0001) or FTLD patients (1.2 [SD 0.2]; p=0.009). Visual interpretation was 100% sensitive and 90% specific for detection of AD. INTERPRETATION (18)F-BAY94-9172 PET discriminates between AD and FTLD or healthy controls and might facilitate integration of Abeta imaging into clinical practice.

Relationship between atrophy and β‐amyloid deposition in Alzheimer disease

Elucidating the role of aggregated β‐amyloid in relation to gray matter atrophy is crucial to the understanding of the pathological mechanisms of Alzheimer disease and for the development of therapeutic trials. The present study aims to assess this relationship.

Amyloid Imaging with 18 F-Florbetaben in Alzheimer Disease and Other Dementias

Amyloid imaging with 18F-labeled radiotracers will allow widespread use, facilitating research, diagnosis, and therapeutic development for Alzheimer disease. The purpose of the study program was to compare cortical amyloid deposition using 18F-florbetaben and PET in controls and subjects with mild cognitive impairment (MCI), frontotemporal lobar degeneration (FTLD), dementia with Lewy bodies (DLB), vascular dementia (VaD), Parkinson disease (PD), and Alzheimer disease (AD). Methods: One hundred nine subjects in 3 clinical studies at Austin Health were reviewed: 32 controls, 20 subjects with MCI, and 30 patients with AD, 11 with FTLD, 7 with DLB, 5 with PD, and 4 with VaD underwent PET after intravenous injection of 300 MBq of 18F-florbetaben. Standardized uptake value ratios (SUVR) using the cerebellar cortex as a reference region were calculated between 90 and 110 min after injection. Results: When compared with the other groups, AD patients demonstrated significantly higher SUVRs (P < 0.0001) in neocortical areas. Most AD patients (96%) and 60% of MCI subjects showed diffuse cortical 18F-florbetaben retention. In contrast, only 9% of FTLD, 25% of VaD, 29% of DLB, and no PD patients and 16% of controls showed cortical binding. Although there was a correlation between Mini Mental State Examination and β-amyloid burden in the MCI group, no correlation was observed in controls, FTLD or AD. Conclusion: 18F-florbetaben had high sensitivity for AD, clearly distinguished patients with FTLD from AD, and provided results comparable to those reported with 11C-Pittsburgh Compound B in a variety of neurodegenerative diseases.

Multilingual Information Access for Text, Speech and Images

What Happened in CLEF 2004?.- What Happened in CLEF 2004?.- I. Ad Hoc Text Retrieval Tracks.- CLEF 2004: Ad Hoc Track Overview and Results Analysis.- Selection and Merging Strategies for Multilingual Information Retrieval.- Using Surface-Syntactic Parser and Deviation from Randomness.- Cross-Language Retrieval Using HAIRCUT at CLEF 2004.- Experiments on Statistical Approaches to Compensate for Limited Linguistic Resources.- Application of Variable Length N-Gram Vectors to Monolingual and Bilingual Information Retrieval.- Integrating New Languages in a Multilingual Search System Based on a Deep Linguistic Analysis.- IR-n r2: Using Normalized Passages.- Using COTS Search Engines and Custom Query Strategies at CLEF.- Report on Thomson Legal and Regulatory Experiments at CLEF-2004.- Effective Translation, Tokenization and Combination for Cross-Lingual Retrieval.- Two-Stage Refinement of Transitive Query Translation with English Disambiguation for Cross-Language Information Retrieval: An Experiment at CLEF 2004.- Dictionary-Based Amharic - English Information Retrieval.- Dynamic Lexica for Query Translation.- SINAI at CLEF 2004: Using Machine Translation Resources with a Mixed 2-Step RSV Merging Algorithm.- Mono- and Crosslingual Retrieval Experiments at the University of Hildesheim.- University of Chicago at CLEF2004: Cross-Language Text and Spoken Document Retrieval.- UB at CLEF2004: Cross Language Information Retrieval Using Statistical Language Models.- MIRACLEs Hybrid Approach to Bilingual and Monolingual Information Retrieval.- Searching a Russian Document Collection Using English, Chinese and Japanese Queries.- Dublin City University at CLEF 2004: Experiments in Monolingual, Bilingual and Multilingual Retrieval.- Finnish, Portuguese and Russian Retrieval with Hummingbird SearchServerTM at CLEF 2004.- Data Fusion for Effective European Monolingual Information Retrieval.- The XLDB Group at CLEF 2004.- The University of Glasgow at CLEF 2004: French Monolingual Information Retrieval with Terrier.- II. Domain-Specific Document Retrieval.- The Domain-Specific Track in CLEF 2004: Overview of the Results and Remarks on the Assessment Process.- University of Hagen at CLEF 2004: Indexing and Translating Concepts for the GIRT Task.- IRIT at CLEF 2004: The English GIRT Task.- Ricoh at CLEF 2004.- GIRT and the Use of Subject Metadata for Retrieval.- III. Interactive Cross-Language Information Retrieval.- iCLEF 2004 Track Overview: Pilot Experiments in Interactive Cross-Language Question Answering.- Interactive Cross-Language Question Answering: Searching Passages Versus Searching Documents.- Improving Interaction with the User in Cross-Language Question Answering Through Relevant Domains and Syntactic Semantic Patterns.- Cooperation, Bookmarking, and Thesaurus in Interactive Bilingual Question Answering.- Summarization Design for Interactive Cross-Language Question Answering.- Interactive and Bilingual Question Answering Using Term Suggestion and Passage Retrieval.- IV. Multiple Language Question Answering.- Overview of the CLEF 2004 Multilingual Question Answering Track.- A Question Answering System for French.- Cross-Language French-English Question Answering Using the DLT System at CLEF 2004.- Experiments on Robust NL Question Interpretation and Multi-layered Document Annotation for a Cross-Language Question/Answering System.- Making Stone Soup: Evaluating a Recall-Oriented Multi-stream Question Answering System for Dutch.- The DIOGENE Question Answering System at CLEF-2004.- Cross-Lingual Question Answering Using Off-the-Shelf Machine Translation.- Bulgarian-English Question Answering: Adaptation of Language Resources.- Answering French Questions in English by Exploiting Results from Several Sources of Information.- Finnish as Source Language in Bilingual Question Answering.- miraQA: Experiments with Learning Answer Context Patterns from the Web.- Question Answering for Spanish Supported by Lexical Context Annotation.- Question Answering Using Sentence Parsing and Semantic Network Matching.- First Evaluation of Esfinge - A Question Answering System for Portuguese.- University of Evora in QA@CLEF-2004.- COLE Experiments at QA@CLEF 2004 Spanish Monolingual Track.- Does English Help Question Answering in Spanish?.- The TALP-QA System for Spanish at CLEF 2004: Structural and Hierarchical Relaxing of Semantic Constraints.- ILC-UniPI Italian QA.- Question Answering Pilot Task at CLEF 2004.- Evaluation of Complex Temporal Questions in CLEF-QA.- V. Cross-Language Retrieval in Image Collections.- The CLEF 2004 Cross-Language Image Retrieval Track.- Caption and Query Translation for Cross-Language Image Retrieval.- Pattern-Based Image Retrieval with Constraints and Preferences on ImageCLEF 2004.- How to Visually Retrieve Images from the St. Andrews Collection Using GIFT.- UNED at ImageCLEF 2004: Detecting Named Entities and Noun Phrases for Automatic Query Expansion and Structuring.- Dublin City University at CLEF 2004: Experiments with the ImageCLEF St. Andrews Collection.- From Text to Image: Generating Visual Query for Image Retrieval.- Toward Cross-Language and Cross-Media Image Retrieval.- FIRE - Flexible Image Retrieval Engine: ImageCLEF 2004 Evaluation.- MIRACLE Approach to ImageCLEF 2004: Merging Textual and Content-Based Image Retrieval.- Cross-Media Feedback Strategies: Merging Text and Image Information to Improve Image Retrieval.- ImageCLEF 2004: Combining Image and Multi-lingual Search for Medical Image Retrieval.- Multi-modal Information Retrieval Using FINT.- Medical Image Retrieval Using Texture, Locality and Colour.- SMIRE: Similar Medical Image Retrieval Engine.- A Probabilistic Approach to Medical Image Retrieval.- UB at CLEF2004 Cross Language Medical Image Retrieval.- Content-Based Queries on the CasImage Database Within the IRMA Framework.- Comparison and Combination of Textual and Visual Features for Interactive Cross-Language Image Retrieval.- MSU at ImageCLEF: Cross Language and Interactive Image Retrieval.- VI. Cross-Language Spoken Document Retrieval.- CLEF 2004 Cross-Language Spoken Document Retrieval Track.- VII. Issues in CLIR and in Evaluation.- The Key to the First CLEF with Portuguese: Topics, Questions and Answers in CHAVE.- How Do Named Entities Contribute to Retrieval Effectiveness?.

Applying summarization techniques for term selection in relevance feedback

Query-expansion is an effective Relevance Feedback technique for improving performance in Information Retrieval. In general query-expansion methods select terms from the complete contents of relevant documents. One problem with this approach is that expansion terms unrelated to document relevance can be introduced into the modified query due to their presence in the relevant documents and distribution in the document collection. Motivated by the hypothesis that query-expansion terms should only be sought from the most relevant areas of a document, this investigation explores the use of document summaries in query-expansion. The investigation explores the use of both context-independent standard summaries and query-biased summaries. Experimental results using the Okapi BM25 probabilistic retrieval model with the TREC-8 ad hoc retrieval task show that query-expansion using document summaries can be considerably more effective than using full-document expansion. The paper also presents a novel approach to term-selection that separates the choice of relevant documents from the selection of a pool of potential expansion terms. Again, this technique is shown to be more effective that standard methods.

Query dependent pseudo-relevance feedback based on wikipedia

Pseudo-relevance feedback (PRF) via query-expansion has been proven to be e®ective in many information retrieval (IR) tasks. In most existing work, the top-ranked documents from an initial search are assumed to be relevant and used for PRF. One problem with this approach is that one or more of the top retrieved documents may be non-relevant, which can introduce noise into the feedback process. Besides, existing methods generally do not take into account the significantly different types of queries that are often entered into an IR system. Intuitively, Wikipedia can be seen as a large, manually edited document collection which could be exploited to improve document retrieval effectiveness within PRF. It is not obvious how we might best utilize information from Wikipedia in PRF, and to date, the potential of Wikipedia for this task has been largely unexplored. In our work, we present a systematic exploration of the utilization of Wikipedia in PRF for query dependent expansion. Specifically, we classify TREC topics into three categories based on Wikipedia: 1) entity queries, 2) ambiguous queries, and 3) broader queries. We propose and study the effectiveness of three methods for expansion term selection, each modeling the Wikipedia based pseudo-relevance information from a different perspective. We incorporate the expansion terms into the original query and use language modeling IR to evaluate these methods. Experiments on four TREC test collections, including the large web collection GOV2, show that retrieval performance of each type of query can be improved. In addition, we demonstrate that the proposed method out-performs the baseline relevance model in terms of precision and robustness.

Context-aware Retrieval: Exploring a New Environment for Information Retrieval and Information Filtering

Abstract: The opportunities for context-aware computing are fast expanding. Computing systems can be made aware of their environment by monitoring attributes such as their current location, the current time, the weather, or nearby equipment and users. Context-aware computing often involves retrieval of information: it introduces a new aspect to technologies for information delivery; currently these technologies are based mainly on contemporary approaches to information retrieval and information filtering. In this paper, we consider how the closely related, but distinct, topics of information retrieval and information filtering relate to context-aware retrieval. Our thesis is that context-aware retrieval is as yet a sparsely researched and sparsely understood area, and we aim in this paper to make a start towards remedying this.

Retrieving spoken documents by combining multiple index sources

This paper presents domain-independent methods of spoken document retrieval. Both a continuous-speech large vocabulary recognition system, and a phone-lattice word spotter, are used to locate index units within an experimental corpus of voice messages. Possible index terms are nearly unconstrained; terms not in a 20,000 word recognition system vocabulary can be identified by the word spotter at search time. Though either system alone can yield respectable retrieval performance, the two methods are complementary and work best in combination. Different ways of combining them are investigated, and it is shown that the best of these can increase retrieval average precision for a speakerindependent retrieval system to 85% of that achieved for full-text transcriptions of the test documents.

Echolocation Calls of Bats are Influenced by Maternal Effects and Change over a Lifetime

The greater horseshoe bat, Rhinolophus ferrumequinum, is a model species in echolocation studies, and emits calls containing long constant-frequency (CF) components. The bats have auditory systems tuned sharply to frequencies close to the resting CF (RF) values. Call frequency and neural processing are both flexible within individual bats which use this mode of echolocation. The simple structure of the calls makes them ideal for sonagraphic analysis. Here, in a large-scale and long-term analysis of changes in the vocalizations of bats we show that: (i) the calls of R. ferrumequinum aged 1-28 years vary seasonally and over a lifetime in a predictable manner; and (ii) an infant’s RF is at least partly determined by the RF of its mother. We consider the relative importance of genetic and learning factors upon the correlation between RFS of mothers and offspring.

Foraging behavior and echolocation of wild horseshoe bats Rhinolophus ferrumequinum and R. hipposideros (Chiroptera, Rhinolophidae)

Summary1. Echolocation and foraging behavior of the horseshoe bats Rhinolophus ferrumequinum and R. hipposideros feeding under natural conditions are described. 2. The calls of both species consisted predominantly of a long CF segment, often initiated and terminated by brief FM sweeps of substantial bandwidth. 3. R. hipposideros typically flew close to vegetation, and fed by aerial hawking, gleaning and by pouncing on prey close to the ground. R. hipposideros called with a CF segment close to 112 kHz which is the second harmonic of the vocalization; its calls included low intensity primary harmonics, and had prominent initial and terminal FM sweeps of considerable bandwidth. When searching for prey on the wing it had longer interpulse intervals than R. ferrumequinum, but emitted shorter pulses at a higher repetition rate; overall it had a similar duty cycle to R. ferrumequinum. 4. R. ferrumequinum, calling with a CF segment close to 83 kHz, also used harmonics other than the dominant secondary in its calls, and modified its echolocation according to ecological conditions. This species showed certain parallels with R. rouxi of Asia. It was observed feeding by aerial hawking and by flycatching. When scanning for prey from a perch (perch hunting), calls were of shorter duration, and interpulse intervals were on average longer, than when bats were flying. Mean duty cycle was longer in flight, and the bandwidths and frequency sweep rates of the FM segments in the calls increased in comparison with perched bats. 5. FM information may facilitate determination of target range and the location and nature of obstacles; it may also be involved in the interpretation of echoes and the detection of moving targets among clutter. The rising FM sweep initiating the call in both species when flying (and to a lesser extent perch hunting) in the wild must have a significant adaptive role, and should be considered an essential component of the call; rhinolophids should be termed ‘FM/CF/FM’ bats.