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- Friman, Ola, 1975-, et al.
(author)
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Recognizing emphysema - A neural network approach
- 2002
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In: Pattern Recognition, 2002. Proceedings. 16th International Conference on (Volume:1). - : IEEE Computer Society. ; , s. 512-515
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Conference paper (peer-reviewed)abstract
- An accurate and fully automatic method for detecting and quantifying emphysema in CT-images is presented. The method is based on an image preprocessing step followed by a neural network classifier trained to separate true emphysema from artifacts. The proposed approach is shown to be superior to an established method when applied on real patient data.
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| 2. |
- Knutsson, Mikael, et al.
(author)
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Distribution of mRNA for VIP and PACAP receptors in human cerebral arteries and cranial ganglia.
- 2002
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In: NeuroReport. - 1473-558X. ; 13:4, s. 507-509
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Journal article (peer-reviewed)abstract
- The distribution of mRNA for pituitary adenylate cyclase-activating polypeptide (PACAP) type 1 (PAC1) and vasoactive intestinal polypeptide (VIP) types 1 and 2 (VPAC1 and VPAC2, respectively) receptors was examined by reverse transcriptase polymerase chain reaction (RT-PCR) in human cerebral arteries and in trigeminal, otic, sphenopalatine and superior cervical ganglia. RT-PCR products of the expected sizes were detected in the arteries, in both the presence and absence of endothelium. In the majority (80%) of the trigeminal, otic and superior cervical ganglia, mRNA for all three receptors were found (n = 5). However, in the sphenopalatine ganglion neither VPAC2 nor PAC1 was detected (n = 2). This finding indicates the occurrence of both prejunctional (ganglia) and postjunctional (vessels) location of VIP and PACAP receptors.
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| 3. |
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| 4. |
- Knutsson, Mikael, 1974
(author)
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On Power Estimation and Score Predictions in Affected Sib-Pair Linkage Analysis
- 2002
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Doctoral thesis (other academic/artistic)abstract
- This thesis consists of three papers in statistical genetics, with the emphasis on affected sib-pair linkage analysis. In Paper A, a method to derive the power of linkage analysis in genome scans, using a stepwise approach, is presented. A simulation method to generate marker data is described and power functions are obtained combining the marker simulations with calculations of appropriate linkage statistic moments and a multivariate normal approximation. The approach is tested and illustrated in an example regarding multiple sclerosis. Paper B treats the situation when the family reproduction processes are interfered by the births of affected offspring. The emphasis is on negative> interference, i.e. when the birth of an affected offspring reduces the probability of further reproduction, denoted limitation. The effects of limitation, in connection to the estimation of the sibling prevalence and the power of affected sib-pair analysis, are discussed. Some results are also given for the opposite case of positive interference, denoted compensation. In Paper C, a prediction score graph is derived to compensate for incomplete information in linkage analysis. Contrary to the conservative nonparametric linkage (NPL) score, where the calculations are conditional on the null hypothesis of no linkage, the prediction score is derived conditional on an alternative hypothesis, estimated from the existing data. Performing a joint analysis, using both the NPL- and the prediction graph, new potential gene harbouring regions may be identified. Furthermore, regions originally displaying large peaks, despite low information content, can be reanalysed so that the disease loci can be located with an increased accuracy. The value of the prediction score is illustrated in an example regarding the celiac disease. MSC 2000 subject classification: 62P10, 92D10
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| 5. |
- Sundberg, Mikael, et al.
(author)
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Fibre-optic array for curvature assessment : application in otitis diagnosis
- 2004
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In: Medical & Biological Engineering & Computing. - 0140-0118. ; 42:2, s. 245-252
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Journal article (peer-reviewed)abstract
- A contact-free sensor consisting of two parallel optical-fibre arrays was designed to assess surface shapes of diffusely scattering media. By sequentially illuminating objects using one fibre array and detecting the diffusely back-scattered photons by the other, a source-detector intensity matrix was formed, where the matrix element (i, j) was the intensity at detector j when light source i was excited. Experimental data from convex and concave polyacetal plastic surfaces were recorded. A mathematical model was used for simulating source-detector intensity matrices for the surfaces analysed in the experiments. Experimental results from the system were compared with the theoretically expected results provided by the mathematical model. The shape and relative amplitude showed similar behaviour in the experiments and simulations. A convex/concave discriminator index D, representing the detected intensity difference between two source-detector separations, was defined. The relative dynamic range of D, defined as the difference between the maximum and the minimum divided by the mean of the index, was 1.37 for convex surfaces and 0.68 for concave surfaces, at a measuring distance of 4.5mm. The index D was positive for convex surfaces and negative for concave surfaces, which showed that the system could distinguish between convex and concave surfaces, an important result for the diagnosis of otitis media.
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