Content-based access to oral and maxillofacial radiographs.

OBJECTIVES: Content-based access (CBA) to medical image archives, i.e. data retrieval by means of image-based numerical features computed automatically, has capabilities to improve diagnostics, research and education. In this study, the applicability of CBA methods in dentomaxillofacial radiology is evaluated. METHODS: Recent research has discovered numerical features that were successfully applied for an automatic categorization of radiographs. In our experiments, oral and maxillofacial radiographs were obtained from the day-to-day routine of a university hospital and labelled by an experienced dental radiologist regarding the technique and direction of imaging, as well as the displayed anatomy and biosystem. In total, 2000 radiographs of 71 classes with at least 10 samples per class were analysed. A combination of co-occurrence-based texture features and correlation-based similarity measures was used in leaving-one-out experiments for automatic classification. The impact of automatic detection and separation of multi-field images and automatic separability of biosystems were analysed. RESULTS: Automatic categorization yielded error rates of 23.20%, 7.95% and 4.40% with respect to a correct match within the first, fifth and tenth best returns. These figures improved to 23.05%, 7.00%, 4.20%, and 20.05%, 5.65% and 3.25% if automatic decomposition was applied and the classifier was optimized to the dentomaxillofacial imagery, respectively. The dentulous and implant systems were difficult to distinguish. Experiments on non-dental radiographs (10,000 images of 57 classes) yielded 12.6%, 5.6% and 3.6%. CONCLUSION: Using the same numerical features as in medical radiology, oral and maxillofacial radiographs can be reliably indexed by global texture features for CBA and data mining.

Quality of film-based and digital panoramic radiography.

OBJECTIVES: To compare the image quality of panoramic radiographs obtained with storage phosphor plate and screen-film systems. METHODS: Panoramic radiographs were taken in 60 patients both with film and with a storage phosphor plate system (30 with DenOptix (Dentsply/Gendex) and 30 with Digora PCT). The images were obtained with either the Cranex Tome or the Scanora multimodal X-ray unit. The screen-film combination was Lanex medium/Curix Ortho HT-G. The digital images were displayed as 8-bit images with a 300 dpi resolution on a 19" monitor and the film images were placed on a light box adjacent to the screen. Ten observers evaluated diagnostic image quality by means of visual grading analysis of different anatomical structures. The structures were scored as being visualized much better (5), better (4), equal (3), worse (2) or much worse (1) in the digital images than in the film images. The mean number of patients receiving the different scores was calculated. Statistical methods used were Wilcoxon sign rank test and Mann-Whitney test. RESULTS: On average, visualization was equal in 19 of the 30 patients imaged using Digora PCT; in 10 it was worse. The corresponding values for DenOptix were 20 and 9. The difference between the film-based and the digital images was small but statistically significant (P<0.0001). The difference between the two image plate systems was not statistically significant (P>/=0.17). CONCLUSIONS: It was concluded that digital panoramic radiographs are equivalent to film-based images for most purposes.

Postweaning multisystemic wasting syndrome--PMWS. the first year with the disease in Sweden.

Postweaning multisystemic wasting syndrome (PMWS) is causally associated with porcine circovirus type 2 (PCV2) infection of pigs. PCV2 has been present in the Swedish pig population for at least ten years. Despite this, no signs of PMWS were observed in pigs of Sweden until 2003. Since then the disease has spread slowly in Sweden. The pig population of Sweden is geographically isolated, the density of pigs and the pathogen load in the country is low and the trade of animals is organised in a restricted way. To date, there has been little information placed in the peer-reviewed literature on the study of the spread of PMWS in a country during the early phase of the disease outbreak, mainly because diagnosis of PMWS has only occurred after the disease has been recognised on a number of farms. This manuscript documents the studies to date on the PMWS outbreak in Sweden which has been closely monitored since the initial outbreak of diseases on a single farm in 2003 was diagnosed. In Sweden PMWS was officially reported for the first time at a progeny test station during December 2003. One year later sixteen herds have been diagnosed and reported to the authorities: one progeny test station, one nucleus herd, thirteen piglet producers or integrated herds and one specialised fattening herd. Fifteen suspected cases have been deemed negative for PMWS with disease scenarios associated with Lawsonia intracellularis, Brachyspira pilosicoli, Mycoplasma hyopneumoniae, shortcomings in feed composition etc. To date, one year after the index case was reported ten other herds suspected for PMWS are under observation. The PMWS cases are concentrated into the southern part of Sweden. However, the disease is spreading slowly, and in general there are no obvious physical links between affected herds. The data generated to date in Sweden suggest that introduction of a new contagious microbe into the country that is responsible for the PMWS outbreaks appears unlikely, as does the spread of PMWS via semen.

Quality of digital pre-implant tomography: comparison of film-screen images with storage phosphor images at normal and low dose.

OBJECTIVES: The aim of this pilot study was to compare the image quality of a storage phosphor system with that of conventional film-screen in pre-implant conventional tomography, and to test the influence of radiation dose on image quality in the storage phosphor system. METHODS: Cross-sectional conventional tomographic images (Scanora) technique) were obtained on 11 patients with film-screen and with storage phosphor image plates (Digora) PCT) at normal and low doses. Ten observers graded the visibility of anatomical structures of importance for implant planning. A three-step rating scale was used, where -1 =worse, 0=equal and 1=better than the reference image. RESULTS: Although image quality was graded as equally good in the majority (59%) of images, the storage phosphor system scored significantly lower than film-screen (-0.37 vs 0.00, respectively) for all the images. Low dose storage phosphor images were rated significantly lower (-0.21) than normal dose images (0.00). CONCLUSIONS: In the majority of patients, anatomic structures of importance for implant planning are visualized equally well on storage phosphor and film-screen images. However, where differences do exist, storage phosphor images score lower than film-screen images. Dose reduction in the storage phosphor system had a negative influence on image quality.

Deaf pupils' reasoning about scientific phenomena: school science as a framework for understanding or as fragments of factual knowledge.

Many studies have been conducted on hearing pupils' understanding of science. Findings from these studies have been used as grounds for planning instruction in school science. This article reports findings from an interview study of how deaf pupils in compulsory school reason about phenomena in a science context. The results reveal that there is variation in the extent to which pupils use scientific principles for reasoning about science phenomena. For some pupils, school science seems to have little to offer as a framework for reasoning. The results also generate questions about the need in school instruction of deaf and hard-of-hearing pupils to consider the specific teaching and learning situations in a deaf environment.

Norms for 439 action events: familiarity, emotionality, motor activity, and memorability.

A total of 128 male and female university students having Swedish as their mother tongue rated 439 actions on a 7-point scale in the dimensions of Familiarity, Emotionality, Motor Activity, and Memorability under instructions to imagine themselves performing each action (e.g., "to roll a ball", "to break a match"). Overall mean ratings were higher for women than for men in all four dimensions. High reliabilities were obtained in each scale. Intercorrelations between the dimensions were low to moderate, indicating that different characteristics of the actions were assessed. It is demonstrated that the ratings of the four dimensions are in agreement with previous categorisations of actions along the same or similar dimensions and with findings related to memory performance. Furthermore, control studies performed on the Familiarity dimension show that norm values are highly correlated with ratings given by participants in standard enacting and nonenacting conditions and with ratings in a condition where objects were present. These norms offer possibilities to control for and vary item characteristics of importance in the study of actions and the memory of actions.

Panoramic radiography in dental diagnostics.

Panoramic radiography was studied with the aim to answer some questions about technical and diagnostic properties regarding dental diagnostics. A unit with an intraoral X-ray tube was studied regarding radiation beam area, absorbed doses, and image quality for various screen-film combinations. The beam area for lateral views was wider than optimal and the contact dose high. Modifications of shielding cylinders would reduce both radiation beam and contact dose. One screen-film combination was most sensitive and produced radiographs with best subjectively perceived image quality. Agreement between panoramic (rotational and intraoral X-ray tube techniques) and intraoral radiography in diagnosis of periapical pathology, assessment of marginal bone height, and caries diagnosis was evaluated in 400 patients. Average agreement between panoramic and intraoral radiographs in periapical diagnosis was 55% for the rotational and 46% for the intraoral tube technique. Agreement in marginal bone height was 55% and 49%, respectively and in caries diagnosis 34% and 46%. Radiographs from 40 patients were used to evaluate a procedure starting with rotational panoramic radiography followed by intraoral radiographs considered necessary to achieve a comprehensive examination of teeth and surrounding bone. The number of intraoral radiographs, information loss, and monetary costs with this procedure were evaluated. Mean number of adjunct intraoral radiographs was 5.1 per patient whilst 8.5 should have been chosen to satisfy a "gold standard" used. Monetary costs were similar for an optimal combination of panoramic and intraoral radiography as for a survey with 20 intraoral images Sensitivity for a combination of radiographs was 80-96% in periapical diagnosis and marginal bone loss assessment, and 42-96% in caries diagnosis. Specificity was 95-97% for periapical and caries diagnosis and 50-92% for marginal bone loss. Radiographs from six conventional units and two programs ("dental" and "jaw" panorama) of a new multi-modal unit were compared in diagnostic quality of periapical and crestal bone areas. Number of adjunct intraoral radiographs to achieve a comprehensive evaluation of periapical and marginal bone was estimated. Quality of the "dental" panorama was significantly better than that of other machines/programs. There were no significant differences between images obtained with conventional units and the "jaw" panorama. Number of adjunct intraoral radiographs was lowest for the "dental" panorama. Quality obtained with an old unit was similar to that from modern machines. Rotational and intraoral X-ray tube panoramic radiography perform equally well. Agreement between panoramic and intraoral radiography is not sufficient for panoramic radiography to be used alone to diagnose periapical lesions, marginal bone loss and caries. It is possible to perform a full-mouth survey with a combination of panoramic and intraoral radiography but when limited regions need to be examined intraoral radiography is the method of choice.

Panoramic and restrictive intraoral radiography in comprehensive oral radiographic diagnosis.

It has been suggested that information from the panoramic radiograph makes it possible to appropriately select supplementary intraoral radiographs to achieve a comprehensive examination of teeth and surrounding bone with less patient dose but no significant information loss. Number of intraoral radiographs selected, information loss and monetary costs with such a procedure was evaluated in 40 patients. Results show that, on average, 5.1 intraoral radiographs were selected to supplement the panoramic radiograph. Of these, 3.1 contained information different from that in the panoramic radiograph but 2.0 did not. An additional 3.4 ought to have been taken to reach the result of the 'gold standard' achieved from a simultaneous evaluation by two expert observers of panoramic radiographs and full mouth surveys with intraoral radiographs. Sensitivity for the combined use of panoramic and supplementary intraoral radiographs was high (80-96%, depending on type of teeth) as regards periapical lesions and marginal bone loss but low for caries (42-96%). Specificity was high for periapical lesions and caries (95-97%) but low for marginal bone loss (50-92%). In Sweden, patient costs become almost the same for a combination of panoramic radiography and 8.5 intraoral radiographs as for a full mouth survey comprising 20 intraoral radiographs. The radiation dose reduction is 40-50% considering that the dose from a panoramic radiograph approximately corresponds to 2-4 intraoral radiographs.(ABSTRACT TRUNCATED AT 250 WORDS)

Image quality in panoramic radiography.

Because of the increase in panoramic radiography it is important to know if image quality has improved with recent technical developments and if there are differences between the different machines that can justify the difference in price. Six conventional panoramic units and the two panoramic programs (dental and jaw panorama) of the Scanora (Soredex, Orion Corporation Ltd, Helsinki, Finland) multi-modal unit were compared by evaluating the radiographs for subjective image quality and estimating the number of additional intra-oral radiographs necessary for a comprehensive evaluation of the periapical and periodontal bone status. Patients ranging in age from 40 to 60 years with teeth in all four quadrants were selected at random and radiographed with each machine or program. Thirty matching radiographs were selected from our archives in order to evaluate one machine (Orthopantomograph 5, Siemens AG, Bensheim, Germany) which was no longer in use. Seven oral radiologists scored the image quality of between 34 and 36 of the 240 radiographs on a 4-point scale and recorded the additional radiographs needed. The results showed that the mean score for the Scanora dental panorama was significantly higher than mean scores for the other machines/programs for both the periapical and crestal bone. The mean scores for the conventional machines and the Scanora jaw panorama program were not significantly different from each other. The image quality of radiographs obtained with the Orthopantomograph 5 was similar to that attained with the more modern machines. The mean number of additional intra-oral radiographs was lowest for the Scanora dental panorama. We conclude that the Scanora dental panorama program provided the best subjective image quality.

Attention and performance in miniature golf across the life span.

Highly skilled adolescent (15-19 years), young (25-35 years), middle-aged (50-57 years), and older (58-73 years) miniature golf players were examined in training and competitive conditions. Number of shots, heart rate, ratings of anxiety, and concentration time were registered. IN addition, two attentional subscales from the Test of Attentional and Interpersonal Style (TAIS) inventory (Nideffer, 1976) were administered. Results indicated (a) parallel increases of heart rate and rated anxiety in competition for all age groups, (b) improvement of motor performance in competition for adolescent and young-adult players, and deterioration of motor performance in competition for middle-aged and older players, and (c) increased concentration time for the two younger samples, and decreased concentration time for the two older samples in competition. As well, the TAIS data indicated greater self-perceived external and internal distractability in the two older, compared to the two younger samples. This age-related vulnerability to distractions was shown to partly mediate age differences in competitive motor performance. The overall pattern of outcome is discussed relative to the view that the adult aging process is associated with a deficit in the ability to handle situations of high arousal due to age-related deficits in a variety of basic cognitive capacities.

Comparison of panoramic and intraoral radiography for the diagnosis of caries and periapical pathology.

Panoramic and intraoral radiographs from 400 consecutive patients were compared for their ability to demonstrate periapical pathology and caries. Two hundred panoramic radiographs were exposed with the rotational technique and 200 with the intraoral X-ray tube technique. Periapical osteolytic and sclerotic lesions as well as approximal caries were recorded independently by two observes. Agreement with intraoral radiographs for periapical osteolytic lesions was, on average, 63% for the rotational and 55% for the intraoral X-ray tube technique and for sclerotic lesions 40% and 36%, respectively. The agreement varied with tooth type and lesion size. When teeth without periapical lesions were also included in the comparisons, the values for agreement were over 96%. Interobserver agreement for periapical osteolytic lesions was 61% for the rotational and 56% for the intraoral X-ray tube technique. The corresponding values for sclerotic lesions were 29% and 23%. Intraobserver agreement for periapical osteolytic lesions was 71% for the rotational and 67% for the intraoral X-ray tube technique. The corresponding values for sclerotic lesions were 46% and 56%. Agreement with intraoral radiographs for enamel caries was, on average, 21% for the rotational and 27% for the intraoral X-ray tube technique and for dentinal lesions 44% and 53%, respectively. When caries-free approximal surfaces were also included in the comparisons, the values for agreement were over 95%. It is concluded that panoramic and intraoral radiography perform equally well as diagnostic tools for the detection of periapical lesions, although the results are not identical.(ABSTRACT TRUNCATED AT 250 WORDS)

Agreement between panoramic and intra-oral radiography in the assessment of marginal bone height.

Panoramic and intra-oral radiographs from 400 consecutive patients were evaluated for the assessment of the marginal bone height. Two hundred panoramic radiographs were exposed with the rotational technique and 200 with the intra-oral X-ray tube technique. Measurements of the approximal marginal bone level were independently performed by two observers. Complete agreement between panoramic and intra-oral radiographs was, on average, obtained in 55% and 49% of the sites, respectively. When the criterion for agreement was widened to include recordings with a difference of +/- 1 mm, the agreement was on average 87% irrespective of the techniques compared. The agreement varied with tooth type and severity of the marginal bone loss. Angular bony defects and furcation involvements were recorded separately. For angular bony defects there was a variation in agreement from 33% to 46% for the rotational technique and from 35% to 51% for the intra-oral X-ray tube technique depending on localization. Furcation involvements of the molars were equally recorded in 60% and 59%, respectively, but in only 12% and 28% for the upper premolars. Interobserver agreement was 58% for the intra-oral radiographs, 60% and 59% for the two panoramic techniques. Mean intra-observer agreement was 68%, 66% and 68%. It is concluded that panoramic radiography can often be used for the assessment of marginal bone loss alone, supplemented when necessary by intra-oral radiographs.

On the generalizability of the age-related decline in coping with high-arousal conditions in a precision sport: replication and extension.

Two field experiments are reported in which highly skilled miniature golf players varying in age were examined during training and competition (Swedish championships). Number of shots, heart rate, and subjective ratings of anxiety were registered. Results indicated that young and older adult players exhibited a similar increase of competitive anxiety from training to competition, as evidenced by both measures of arousal. In addition, whereas older players deteriorated in motor performance during competitive play, young players improved motor performance in competition. This pattern of results replicates and extends previous research. It is suggested that the data reflect age-related differences in the ability to cope with high-arousal conditions as a result of age-related deficits in task-relevant cognitive abilities.

Cognitive processes among skilled miniature golf players: effects of instructions on motor performance, concentration time, and perceived difficulty.

Highly skilled miniature golf players were examined on a simplified miniature golf task under different instructional conditions. Results indicated that requirements to attend to a variety of technical aspects of the game during preparation impaired motor performance, whereas providing players with those aspects of the game they reported thinking of did not affect motor performance. Data on concentration time and perceived difficulty indicated that increasing cognitive demands were associated with a decline in motor precision. The overall pattern of results was interpreted such that attention directed at technical aspects of the game interfered with the players' normal cognitive activity. Susceptibility to interference is a characteristic feature of controlled cognitive operations. Thus, the present results are consistent with the view that conscious cognitive activity may support motor behavior also at late stages of skill development.

Age differences in the effects of background noise on motor and memory performance in a precision sport.

Young (M = 27.8 years) and older (M = 53.2 years) highly skilled miniature golf players were observed in competitions in which the background noise was either tape-recorded traffic sounds or a radio broadcasting a soccer game. Varying in meaningfulness, the two conditions were examples of types of noise which prevail during normal competitive activity in miniature golf. Measures of motor performance, arousal, and memory for shots were registered. Results showed that players played less well and remembered fewer shots under the radio broadcasting condition than in the traffic noise condition; whereas younger players performed equally well for both measures in both noise conditions. In neither age group was the level of arousal affected by type of noise. The results suggest that there may be an age-related impairment in selective attention situations, and, in contrast to past findings, also when the task does not demand that the irrelevant noise stimuli be searched. A claim is made that the benefit of domain-specific expertise in older people is reduced in situations of high arousal or increased cognitive demands.

Age differences in heart rate patterns during concentration in a precision sport: implications for attentional functioning.

Highly skilled young (M = 29.5 years) and older (M = 50.0 years) miniature golf players were observed in relaxed training and high-arousal competition rounds. Motor performance (number of shots), subjective ratings of anxiety, and heart rate were registered. Results showed a similar increase of arousal from training to competition for both age groups. However, the older group deteriorated in motor performance from training to competition, whereas the younger group played equally well on both occasions. Results from continuous measurement of heart rate indicated a deceleration during the concentration phases among the younger players, and the magnitude of deceleration increased from training to competition. In contrast, heart rate accelerated during training among the older players, the magnitude of the heart rate change decreasing from training to competition. This evidence suggests that the deterioration in motor performance observed in older players in stressful competitive activity may be due to age-related changes in attentional functioning.

Isoprenoid biosynthesis in multiple sclerosis, II. A possible role of NADPH.

Genetic predisposition in MS, influence of fat consumption on the disease, and excretion of lipid metabolites in urine led us to investigate isoprenoid metabolism in this disease. Ubiquinone concentration and biosynthesis was normal in lymphocytes. Cytochrome oxidase, which contains an isoprenoid side chain, was normal in activity. Cholesterol biosynthesis from acetate was found to be elevated in MS, and so was triglyceride biosynthesis. Increased biosynthesis may offer a very simple explanation to all the metabolites excreted (3-methylglutaconic acid, 2-hydroxy-2-methyl-3-butenoic acid and adipic acid). Increased biosynthesis may be caused by an elevated NADPH/NADP ratio, since such an elevation may also account for many other biochemical anomalies in MS. Elevated NADPH/NADP ratio may be of direct importance in the pathogenesis.

Effects of adult age and level of skill on the ability to cope with high-stress conditions in a precision sport.

Younger and older highly skilled and moderately skilled miniature golf players were studied in training and competition. All of the players showed an increase of heart rate and rated anxiety from training to competition. A performance decline in competition was observed for both older players and less accomplished players. Results from a cognitive task (incidental recall of shots) suggest that older players are less proficient in coping with the high-stress conditions in competition, due to an age-related decline in task-relevant cognitive abilities.

Adult age differences in the ability to cope with situations of high arousal in a precision sport.

Three field experiments are reported in which skilled miniature golf players varying in age were studied in three types of activities: training, minor competitions, and large competitions. Performance (i.e., number of shots) and arousal (heart rate and subjective ratings of anxiety) measures were registered in all types of activities. The major finding was that the level of performance of older adult players deteriorated in the large competitions, whereas groups of younger adult players, junior players, and youth players performed at the same level in all three events, although all of the groups exhibited a similar increase in arousal from training and minor competitions to large competitions. We suggest that older players may have a deficit in the ability to compensate for the negative effects of nonoptimal levels of arousal because of impairments in a variety of cognitive abilities critical to successful performance.