A multiresolution approach for contour extraction from brain images

Many image registration methods use head surface, brain surface, or inner/outer surface of the skull to estimate rotation and translation parameters. The inner surface of the skull is also used for intracranial volume segmentation which is considered the first step in segmentation and analysis of brain images. The surface is usually characterized by a set of edge or contour points extracted from cross-sectional images. Automatic extraction of contour points is complicated by discontinuity of edges in the back of the eyes and ears and sometimes by a previous surgery or an inadequate field of view. We have developed an automated method for contour extraction that connects discontinuities using a multiresolution pyramid. Steps of the method are: (1) Contour points are found by an edge-tracking algorithm; (2) A multiresolution pyramid of contour points is constructed; (3) Contour points of reduced images are found; (4) From the continuous contour found at the lowest resolution, contour points at a higher resolution are found; (5) Step 4 is repeated until contour points at the highest resolution (original image) are found. The method runs fast and has been successful in extracting contours from MRI and CT images. We illustrate the method and its performance using MRI and CT images of the human brain.     

Amplitude distribution of calcium sparks in confocal images: theory and studies with an automatic detection method

Determination of the calcium spark amplitude distribution is of critical importance for understanding the nature of elementary calcium release events in striated muscle. In the present study we show, on general theoretical grounds, that calcium sparks, as observed in confocal line scan images, should have a nonmodal, monotonic decreasing amplitude distribution, regardless of whether the underlying events are stereotyped. To test this prediction we developed, implemented, and verified an automated computer algorithm for objective detection and measurement of calcium sparks in raw image data. When the sensitivity and reliability of the algorithm were set appropriately, we observed highly left-skewed or monotonic decreasing amplitude distributions in skeletal muscle cells and cardiomyocytes, confirming the theoretical predictions. The previously reported modal or Gaussian distributions of sparks detected by eye must therefore be the result of subjective detection bias against small amplitude events. In addition, we discuss possible situations when a modal distribution might be observed.     

DullRazor: a software approach to hair removal from images

Recently, there has been a growing number of studies applying image processing techniques to analyze melanocytic lesions for atypia and possible malignancy and for total-body mole mapping. However, such lesions can be partially obscured by body hairs. None of these studies has fully addressed the problem of human hairs occluding the imaged lesions. In our previous study we designed an automatic segmentation program to differentiate skin lesions from the normal healthy skin, and learned that the program performed well with most of the images, the exception being those with hairs, especially dark thick hairs, covering part of the lesions. These thick dark hairs confused the program, resulting in unsatisfactory segmentation results. In this paper, we present a method to remove hairs from an image using a pre-processing program we have called DullRazor. This pre-processing step enables the segmentation program to achieve satisfactory results. DullRazor can be downloaded as shareware from http:/(/)www.derm.ubc.ca.     

Computer analysis of mammography phantom images (CAMPI): an application to the measurement of microcalcification image quality of directly acquired digital images

The purpose of this investigation was to apply the recently developed CAMPI (computer analysis of mammography phantom images) method to a Fischer Mammotest Stereotactic Digital Biopsy machine. Another aim was to further elucidate the nature of the empirically introduced CAMPI measures. Images of an American College of Radiology (ACR) accreditation phantom centered on the largest two speck groups were obtained on this machine under a variety of x-ray conditions. An additional measure, alternative SNR (ASNR) is introduced which is complementary to the SNR measure. Analyses of the Mammotest images revealed that the mAs and kVp dependencies of the CAMPI measures could be understood from basic imaging physics principles. It is shown that: (1) the measures reflect the expected linearity of the digital detector and Poisson photon statistics; (2) under automatic exposure control (AEC) conditions the signal (SIG) measure is proportional to subject contrast; and (3) under AEC conditions the noise (NOI) measure is proportional to the square root of the average absorbed photon energy. Correspondence with basic imaging physics principles shows that the measures are significantly free of artifacts. Precision of the CAMPI measures exceeds that of human observers by orders of magnitude. CAMPI measures are expected to be more relevant to clinical mammography than Fourier metrics as the measurements are done on objects of arbitrary shape and size that were designed by the manufacturer to resemble various detection tasks in mammography. It is concluded that CAMPI can perform objective and highly precise evaluations of phantom image quality in mammography. It could be used as a sophisticated quality control tool, as a replacement for the current ACR/MQSA phantom evaluation program, and to evaluate the rapidly evolving digital mammography technology.     

Phylogenetic analysis of nucleotide sequences: an algebraic approach

Retinoids constitute a very promising class of agents for the chemoprevention or treatment of breast cancer. These retinoids exert their biological activity through two distinct classes of retinoic acid (RA) receptors (R), the RAR isotypes (alpha, beta, and gamma) and the three RXR isotypes (alpha, beta, and gamma) and their numerous isoforms which bind as RXR/RAR heterodimers to the polymorphic cis-acting response elements of RA target genes. With respect to these numerous receptor sub-types, the retinoid-induced effects at the biological level include marked modifications with respect to both cell proliferation and cell death (apoptosis), and also in the induction of differentiation processes. The present study aims to characterize the effect which four retinoids (TTNPB, 9-cis-RA, LGD 1069, 4-HPR) with distinct RAR/RXR binding properties induced on various in vitro and in vivo mouse and human breast cancer models. The experiments with the retinoids were carried out in comparison with the anti-estrogen tamoxifen and the anti-progestagen RU-486 compounds. The results show that the 6 compounds under study were markedly more efficient in terms of growth inhibition in the human T-47D cell line when maintained under anchorage-independent culture conditions than when maintained under anchorage-dependent ones. While RU-486 exhibited a weak statistically significant (p < 0.05) influence on the growth of the T-47D stem cells, tamoxifen had a marked inhibitory influence on the growth of these cells. Of the four retinoids, 4-HPR was the least effective since the lowest doses tested (1 and 0.1 nM) exhibited no statistically (p > 0.05) significant influence on the growth of the stem cells. The most efficient retinoid was TTNPB. It was only at the highest dose (10 microM) that tamoxifen and RU-486 showed a weak inhibitory influence on the growth of the T-47D non-stem cells while all 4 retinoids exerted a significant inhibitory influence on the growth of these non-stem cells, with 4-HPR being the most efficient (P < 0.001) at the highest dose, but ineffective (P > 0.05) at the lowest. Tamoxifen and TTNPB were tested in vivo on hormone-sensitive (HS) and hormone-insensitive (HI) strains of the MXT murine mammary carcinoma. While TTNPB appeared to be equally efficient in terms of growth inhibition in both MXT-HS and MXT-HI models, tamoxifen had only a marginal inhibitory influence on the growth of the MXT-HI strain but did inhibit growth in the case of the MXT-HS one. TTNPB was markedly more efficient than tamoxifen in terms of both inhibiting the cell proliferation level (measured by means of computer-assisted microscopy applied to Feulgen-stained nuclei, a method which enables the percentage of cells in the S phase of the cell cycle to be determined) and triggering cell death (measured by means of the determination of the transglutaminase activity) in both the MXT-HI and MXT-HS models. The very significant TTNPB-induced inhibition of the macroscopic MXT-HS growth rate relates to the triggering of cell death (apoptosis) rather than to an inhibition of cell proliferation. All these results clearly indicate that retinoids are very efficient agents against breast cancer, at least as efficient as tamoxifen.     

Application of automatic image segmentation to tibiae and vertebrae from ovariectomized rats

Aqueous extracts from various crude drugs showing a selective inhibition on the induction or effector phase of delayed-type hypersensitivity (DTH) reaction were applied to the new model of liver injury induced in mice by picryl chloride(PCl)-induced DTH. The inhibiting drugs to the induction phase of DTH, Fructus Triburi (FT) and Er-Miao-San (EMS), showed a remarkable improvement against the elevation in serum transaminase levels as well as in histopathological changes when given during this phase. The administration in the effector phase by Rhizoma Smilacis Glabrae (RSG) and Cortex Dictamni (CD), selectively inhibiting the phase of DTH, also significantly improved the liver damage. In addition, RSG and CD showed an almost complete recovery of serum alkaline phosphatase from a persistent decrease in the sustaining process of liver injury when given consecutively for 4 weeks after the elicitation of liver injury. Cyclophosphamide, an immunosuppressive agent, significantly inhibited the enzymatic elevation given in either phase, while it did not affect the ability to sustain liver injury. When the above extracts were given in a combined manner to the same mouse during these two phases, respectively, FT with RSG and EMS with CD showed a distinct synergism against the liver injury. RSG or CD also enhanced the activity of prednisolone in suppressing PCl-induced ear contact sensitivity. These findings suggest that this immunological liver injury may be regulated by a set of selective suppressants to DTH reaction and the suitable application of such agents may pave the way for a new strategy in treating liver damage.     

New approach from lipoprotein disorders to atherosclerosis

To make diagnosis arteriosclerosis directly by biochemical markers is not easy, but to identify risk factors by biochemical markers is useful. Lipoprotein disorder is one such risk factor. Low density lipoproteins (LDL), remnants and small LDL were high risks of coronary disease in Japanese. Moreover, those incidences were significantly higher in diabetes mellitus, especially with nephropathy, and latter two lipoproteins frequently coexisted. Oxidizability of small LDL was the highest among LDLs, indicating that small LDL promotes atherosclerosis by forming oxidized lipids, which enhance complicated lesion of atherosclerosis. The mechanism by which the remnant is retained remains unknown. We measured LPL mass in preheparin serum. Preheparin LPL mass was negatively correlated with triglyceride, and positively correlated with high density lipoprotein cholesterol. Further more, preheparin LPL mass was lower in remnant-positive persons, indicating that preheparin LPL mass might be involved in remnant clearance. Understanding the role and catabolism of LPL itself requires further study.     

New approach to aortic dissection: development of an insertable aortic prosthesis

We have developed a new aortic prosthesis with which we can replace or reinforce the aorta using a simple percutaneous technique. We have named the new prosthesis the shape-memory aortic prosthesis (SAP); it consists of a spiral-shaped nitinol stent and polyurethane tube. It can be compressed inside a 14F catheter at a low temperature and regain its original shape at above 30 degrees C. As a preliminary study, SAP sutureless grafting into the descending aorta was performed on 10 mongrel dogs. We found that when the proper diameter of SAP was applied, it functioned satisfactorily for 3 months or more. A percutaneous placement technique pertinent to the SAP also was developed and tried on 4 animals. Our procedure was applied to Stanford type B dissection models to close the entry point successfully. This newly developed SAP has potential to be applied to emergency cases of human aortic dissections.     

Dye absorption changes in single muscle fibers: an application of an automatic balancing circuit

It is very difficult to record small potential changes in the presence of a large background voltage that drifts. This is particularly true in recording optical changes during excitation of nerve and muscle because the optical changes are usually very small compared with the background. We describe a convenient circuit, which is useful under these circumstances. This circuit automatically balances the background drift. Using this circuit we recorded light absorption changes during excitation of single muscle fibers stained with a fluorescence dye merocyanine 540. The optical change consists of three components. The first component presumably reflects the action potential of the surface membrane and the T-system. The second and the third components are perhaps the movement artifacts from latency relaxation followed by contraction.     

Measurement of the extracellular matrix in glomeruli from patients with diabetic nephropathy using an automatic image analyzer

To elucidate the characteristics of glycoproteins in the mesangial matrix in glomeruli from patients with diabetic nephropathy (DN) in non-insulin-dependent diabetes mellitus (NIDDM), we examined periodic acid-Shiff (PAS) and immunofluorescence staining of types III (III-C), IV (IV-C), V (V-C) and VI (VI-C) collagen, fibronectin (FN), fibrinogen (FBG) and laminin (LN) in the glomeruli of 16 patients with DN and 12 patients with diffuse proliferative glomerulonephritis (DPGN). The percentage of positively staining areas in the glomeruli were calculated using an automatic image analyzer. The percentages of areas positive for PAS, III-C, IV-C, V-C, VI-C or FN in DN were significantly greater than those in DPGN. Moreover, the percentages of PAS-positive areas were significantly correlated with not only IV-C-positive areas, but also FN-positive areas in patients with DN. The percentages of PAS-positive areas were also significantly correlated with the levels of serum creatinine and the degree of proteinuria in these patients. It was concluded that mesangial expansion in this disease might be associated mainly with an increase in IV-C and FN. These changes appear to affect the deterioration of renal function and the appearance of proteinuria, and vice versa.     

Strategies for rare-event detection: an approach for automated fetal cell detection in maternal blood

This article explores the feasibility of the use of automated microscopy and image analysis to detect the presence of rare fetal nucleated red blood cells (NRBCs) circulating in maternal blood. The rationales for enrichment and for automated image analysis for "rare-event" detection are reviewed. We also describe the application of automated image analysis to 42 maternal blood samples, using a protocol consisting of one-step enrichment followed by immunocytochemical staining for fetal hemoglobin (HbF) and FISH for X- and Y-chromosomal sequences. Automated image analysis consisted of multimode microscopy and subsequent visual evaluation of image memories containing the selected objects. The FISH results were compared with the results of conventional karyotyping of the chorionic villi. By use of manual screening, 43% of the slides were found to be positive (>=1 NRBC), with a mean number of 11 NRBCs (range 1-40). By automated microscopy, 52% were positive, with on average 17 NRBCs (range 1-111). There was a good correlation between both manual and automated screening, but the NRBC yield from automated image analysis was found to be superior to that from manual screening (P=.0443), particularly when the NRBC count was >15. Seven (64%) of 11 XY fetuses were correctly diagnosed by FISH analysis of automatically detected cells, and all discrepancies were restricted to the lower cell-count range. We believe that automated microscopy and image analysis reduce the screening workload, are more sensitive than manual evaluation, and can be used to detect rare HbF-containing NRBCs in maternal blood.     

Clinical information from medical images. A comparison of two types of ultrasonic image in the detection of focal intrahepatic lesions

If the uncertainty in the diagnosis is measured before and after viewing a diagnostic image, the change in uncertainty is a measure of the information contributed by that image. The formal basis of information theory has been used to calculate the change in uncertainty. These analytical methods have been applied to assess two types of ultrasonic grey-scale image in the demonstration of possible focal intrahepatic lesions.     

Estimating meiotic exchange patterns from recombination data: an application to humans

We present analytical methods to estimate the recombinational history of chromosomes in a human population. Our analysis, similar to those utilized in Drosophila, can be used to construct meiotic maps based upon crossover frequencies observed in family data. We apply this method of exchange estimation to a population of paternally and maternally inherited chromosomes 21. The patterns of chromosomal exchange estimated by this type of analysis are comparable to those obtained by the more technically difficult method of cytologically counting chiasmata among human male meiotic events (sperm). This type of analysis can be applied to both male and female meiosis, circumventing many technical problems inherent to cytological counting. Moreover, the distribution of exchange locations along a chromosome for each exchange type (i.e., single, double, or triple exchanges) can be examined individually, an advantage compared to examination of genetic maps that only provide a summary of these distributions. We discuss how this analysis can be used to examine various assumptions concerning meiotic exchange in humans and investigate properties of the analysis that contribute to the accuracy of the results.     

Strategic consultation: The evolution and application of an efficient approach.

Examines how strategic therapy principles can be applied to consultation practice. These principles focus on a conceptual shift in thinking about a problem and its solution, which allows of more effective and often more innovative solutions to consultation problems. In the 1st principle, failed attempted solutions are seen as reinforcing and maintaining problems. The 2nd principle is the notion that it is necessary to develop solutions that implement 2nd order change. The 3rd concept proposes that it is important to change the consultee's perceptions of the problem in order to assist in developing and implementing new solutions. These principles of strategic consultation can also be applied in many settings and can be incorporated in many other consultation approaches. These principles focus on a conceptual shift in thinking about problems and their solutions. This shift allows for more effective, efficient, and often more innovative solutions to consultation problems. A step-by-step procedure is presented. A case example demonstrates how the approach can be implemented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Data-driven curvilinear reconstructions of 3D MR images: application to cryptogenic extratemporal epilepsy

This paper presents a data-driven method for the reconstruction and visualisation of curvilinear slices from three-dimensional (3D) magnetic resonance (MR) scans of the head. Visualisation of curvilinear slices, rather than standard planar slices, produces symmetrical views of the cortex and allows small abnormalities to be detected by comparing the two hemispheres of the brain. In our method, the surface defined by the upper half of the brain is used as a reference shape for curvilinear reconstructions. The brain is first segmented from the 3D scan using a 3D region growing method associated to an unsupervised threshold selection technique. The upper half of the segmented brain is then extracted and fitted by a deformable surface model. This surface is finally interactively moved by the operator in the 3D scan, to visualise the desired curvilinear slice, which is projected on the screen as a two-dimensional image. We show an application of this visualisation technique to the localisation of cerebral epileptogenic lesions. The procedure has proven efficient and handy in clinical use.     

Transchoroidal approach to the third ventricle: an anatomic study of the choroidal fissure and its clinical application

OBJECTIVE: We review the anatomic features of the lateral ventricle, the foramen of Monro, the third ventricle, and the choroidal fissure, and we describe the transchoroidal approach to the third ventricle. This approach consists of opening the taenia fornicis of the choroidal fissure in the body of the lateral ventricle and approaching the third ventricle between the two internal cerebral veins. This route allows further posterior enlargement of the foramen of Monro without sacrificing any neural structures. When necessary, the anterior septal vein can be sacrificed. METHODS: Twenty adult cadaveric brains and four adult cadaveric heads were studied, using a magnification ranging from 3 times to 40 times, after perfusion of the arteries and veins with colored latex. RESULTS: The choroidal fissure is a natural cleft between the thalamus and the fornix, and it is identified by following the choroid plexus in the lateral ventricle. The choroid plexus in the body of the lateral ventricle originates from the tela choroidea of the roof of the third ventricle and is apparently attached to the fornix by the taenia fornicis and to the thalamus by the taenia choroidea. The taenia is actually the ependyma that covers the internal wall of the ventricular cavity and the choroid plexus. CONCLUSION: An understanding of the choroidal fissure is fundamental for use of the transchoroidal approach. Unlike transforaminal, subchoroidal, subforniceal, and interforniceal approaches to the third ventricle, which sacrifice some neural or vascular structures, the transchoroidal approach follows a natural route, and certainly it is one of the options to be considered when entry into the third ventricle is required.     

Mitochondrial ND1 gene sequences used to identify echinostome isolates from Australia and New Zealand

Echinostomes were collected in Australia and New Zealand as cercariae, metacercariae or adults. Using DNA sequences from the mitochondrial ND1 gene Echinostoma revolutum and Echinostoma paraensei were discovered in Australia. The presence of a further five, as yet unidentified, echinostome species was inferred in Northern Australia and a further isolate, closely allied to E. revolutum, occurs in New Zealand. ND1 sequences of species within the genus diverge from each other by 9.6-30.8%. Sequence divergence levels among strains within a single species are 0-3.6%. The phylogenetic tree produced from the Australasian isolates, in addition to species described previously, identifies the 37-collar-spine species as a well supported monophyletic group. The five unidentified Australian species cluster away from the 37-collar-spine group. These unidentified species appear to divide further into > 37-collar-spine and < 37-collar-spine clusters. Three strains of E. revolutum, collected as metacercariae from snails, were identified from two ponds located 6 km apart. Two of these strains may be cycling through a planorbid snail, Glyptophysa sp., as first intermediate host; however, this hypothesis could not be confirmed as specimens could not be obtained to match sequences between larvae and adults.     

Inhibition of return to negative emotion: Evidence from an emotional expression detection task.

After the presentation of an uninformative spatial cue, it usually takes participants more time to respond to a target that appears at the cued location when the interval between the cue and target is long. This phenomenon is named inhibition of return (IOR), implying that returning attention to the cued location is inhibited because of attentional disengagement. The present study investigated whether irrelevant emotional information is processed by the attentional system in a similar manner. Uninformative positive and negative emotional cues were presented at the center of the screen, and faces were presented as the target. An emotional expression detection task was used to reveal the inhibitory and facilitatory aftereffects of the attentional processing of the emotional cues. An emotion-based IOR effect on reaction time was observed only after the presence of a negative emotional cue, implying that the attentional system tends to inhibit irrelevant negative emotion but not inhibit irrelevant positive emotion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)