Language-based multimedia information retrieval

This paper describes various methods and approaches for language-based multimedia information retrieval, which have been developed in the projects POP-EYE and OLIVE and which will be developed further in the MUMIS project. All of these project aim at supporting automated indexing of video material by use of human language technologies. Thus, in contrast to image or sound-based retrieval methods, where both the query language and the indexing methods build on non-linguistic data, these methods attempt to exploit advanced text retrieval technologies for the retrieval of non-textual material. While POP-EYE was building on subtitles or captions as the prime language key for disclosing video fragments, OLIVE is making use of speech recognition to automatically derive transcriptions of the sound tracks, generating time-coded linguistic elements which then serve as the basis for text-based retrieval functionality

Effect of articular cartilage proteoglycan depletion on high frequency ultrasound backscatter

AbstractObjective To study the effect of variations of articular cartilage proteoglycans (PG) on high-frequency ultrasound backscatter.Design The study was performed on patellar cartilages of immature and mature rats (N=36). The variation of PG content was induced by enzyme digestion. Control and treated cartilages were explored in vitro using a 55MHz scanning acoustic microscopy, then assessed by histology for the fibrillar collagen organization analysis. The variations of proteoglycan and collagen content were evaluated. Thickness measurements performed on both B-scan images and histologic sections were compared. Ultrasonic radio-frequency signals reflected by the cartilage surface and backscattered from its internal matrix were processed to estimate the integrated reflection coefficient (IRC) and apparent integrated backscatter (AIB).Results Although hyaluronidase treatment of immature and mature cartilages removed approximately 50% of the proteoglycans, the echogenicity level of ultrasound images of degraded cartilages was similar to that of controls. IRC and AIB parameters did not significantly vary. Histologic sections of degraded cartilage displayed no change in collagen fiber organization. The thickness mean values measured by ultrasound in PG-depleted groups were significantly higher than in controls, whereas no significant difference in thickness was detected by histological measurement. The increase in cartilage thickness may potentially be explained by a decrease of speed of sound in PG-depleted cartilages that is more likely subsequent to an increase of water content.ConclusionCurrent results indicate that PG depletion has no significant effect on high frequency ultrasound backscattered from rat patellar cartilage. Ultrasound may provide information about variations of PG content via speed of sound measurement. Copyright 2002 OsteoArthritis Research Society International. Published by Elsevier Science Ltd. All rights reserved

494 MONOLAYER EXPANSION MODALITIES INFLUENCES 3D CHONDROGENIC DIFFERENTIATION OF HUMAN MESENCHYMAL STEM CELLS SEEDED IN COLLAGEN SPONGES

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Magnetic resonance imaging in osteoarthritis: which method best reflects synovial membrane inflammation? Correlations with clinical, macroscopic and microscopic features

SummaryObjectives: To study synovial membrane (SM) inflammation near the patella with different magnetic resonance imaging (MRI) approaches performed using a T1-injected sequence in knee osteoarthritis (OA), and to compare MRI results with macroscopic, microscopic and clinical findings.MethodsFifteen patients fulfilling American College of Rheumatology (ACR) criteria for knee OA and requiring joint lavage completed a functional index (Lequesne's functional index) and a pain visual analog scale (VAS). SM inflammation near the patella was assessed on axial fat saturation post-injected T1 MRI images using three different methods: (1) semi-quantitative score=MRI synovitis score; (2) synovial membrane volume (SMV) analysis; (3) SMV with low (SMVL) (<0.3%/s−1), intermediate (SMVI) (0.3%/s−1 to 1%/s−1) and high (SMVH) (≥1%/s−1) speed of enhancement. Chondral lesions and SM inflammation were macroscopically graded and SM biopsies performed for microscopic scoring.ResultsAll MRI approaches exhibited excellent intra- and inter-observer reproducibility. MRI synovitis score correlated well with macroscopic (r=0.61, P=0.003) and total microscopic scores (r=0.55, P=0.03). Correlations between SMV and macroscopic (r=0.60, P=0.02) and microscopic congestion (r=0.63, P=0.01) were good. SMVH was correlated only with microscopic congestion (r=0.79, P=0.01). Low SMV was associated with neither macroscopic nor microscopic scores. However, it did correlate well with pain-VAS score (r=0.61, P=0.03) and moderately with a functional index (r=0.46, P=0.10).ConclusionThe three MRI approaches used here provided highly reproducible information on SM inflammation near the patella in knee OA. Compared to SMV, MRI synovitis score seems sufficient to assess synovial inflammation but high SMV is an appropriate indicator of vascular congestion, and low SMV reflects pain in knee OA