Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “deconvolution”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources
PubMed2005

Accuracy of dynamic perfusion CT with deconvolution in detecting acute hemispheric stroke.

BACKGROUND AND PURPOSE: Dynamic perfusion CT (PCT) with deconvolution produces maps of time-to-peak (TTP), mean transit time (MTT), regional cerebral blood flow (rCBF), and regional cerebral blood volume (rCBV), with a computerized automated map of the infarct and penumbra. We determined the accuracy of these maps in patients with suspected acute hemispheric stroke. METHODS: Forty-six patients underwent nonenhanced CT and dynamic PCT, with follow-up CT or MR imaging. Two observers reviewed the nonenhanced studies for signs of stroke and read the PCT maps for TTP, MTT, rCBF, and rCBV abnormalities. Sensitivity, specificity, accuracy, and interobserver agreement were compared (Wilcoxon tests). Nonenhanced CT and PCT data were reviewed for stroke extent according to previously reported methods. Sensitivity, specificity, and accuracy of the computerized maps in detecting ischemia and its extent were determined. RESULTS: Compared with nonenhanced CT, PCT maps were significantly more accurate in detecting stroke (75.7-86.0% vs. 66.2%; P <.01), MTT maps were significantly more sensitive (77.6% vs. 69.2%; P <.01), and rCBF and rCBV maps were significantly more specific (90.9% and 92.7%, respectively, vs. 65.0%; P <.01). Regarding stroke extent, PCT maps were significantly more sensitive than nonenhanced CT (up to 94.4% vs. 42.9%; P <.01) and had higher interobserver agreement (up to 0.763). For the computerized map, sensitivity, specificity, and accuracy, respectively, were 68.2%, 92.3%, and 88.1% in detecting ischemia and 72.2%, 91.8%, and 87.9% in showing the extent. CONCLUSION: Dynamic PCT maps are more accurate than nonenhanced CT in detecting hemispheric strokes. Despite limited spatial coverage, PCT is highly reliable to assess the stroke extent.

Adult↗
PubMed2005

Quantitative tissue blood flow evaluation of pancreatic tumor: comparison between xenon CT technique and perfusion CT technique based on deconvolution analysis.

PURPOSE: There has been one report that tissue blood flow (TBF) quantification with xenon CT was effective in predicting the therapeutic response to an anticancer drug in pancreatic cancer. The purpose of this study was to evaluate the correlation between the TBF of pancreatic tumors calculated with xenon CT and those with perfusion CT, in order to evaluate whether perfusion CT could replace xenon CT. MATERIALS AND METHODS: Nine patients with pathologically proved pancreatic tumors who underwent both xenon CT and perfusion CT were included. RESULTS: Quantitative TBF of pancreatic tumors measured by perfusion CT ranged from 22.1 to 196.2 ml/min/100 g (mean+/-SD, 52.6+/-54.8 ml/min/100 g). In contrast, those obtained by xenon CT ranged from 10.3 to 173.6 ml/min/100 g (mean+/-SD, 47.4+/-49.4 ml/min/100 g). There was a good linear correlation between xenon CT and perfusion CT (y=0.8537x+2.48, R2=0.895: p<0.05). CONCLUSION: The TBF of pancreatic tumors measured by xenon CT and perfusion CT techniques showed a close linear correlation. We can expect that perfusion CT based on the deconvolution algorithm may replace xenon CT to predict the effect of pancreatic tumor treatment with anticancer drugs.

Adenocarcinoma↗
PubMed2005

Immunofluorescence deconvolution microscopy and image reconstruction of human defensins in normal and burned skin.

OBJECTIVE: The aim of this study was visualization and localization of the human antimicrobials human beta defensins 1, 2, and 3, neutrophil defensin alpha (human neutrophil peptide), and the cathelicidin LL-37 in normal and burned skin, and determination of the cell types in which these antimicrobials were localized. METHODS: Tissue sections were probed with antimicrobial antibodies, tagged with fluorescently labeled secondary antibodies, and subjected to fluorescence deconvolution microscopy and image reconstruction. Images were generated by stacking multiple-section scans, which were then volume rendered by rotating stacks 360 degrees about an axis, or modeled in 3 dimensions. RESULTS: This technique yields a definitive image, providing a rapid basis for further quantification and manipulation from a full 3-dimensional aspect. In normal skin, human beta defensin-1 was localized to the perinuclear region of keratinocytes; human beta defensin-2 was primarily localized to the stratum germinativum; human beta defensin-3 was found in dendritic cells of the stratum spinosum; human neutrophil peptide was randomly distributed in the papillary dermis; and LL-37 was concentrated in the stratum corneum and along ducts. In burned skin, in which keratinocytes are lost or destroyed, human beta defensin-1 was present in dermal glandular structures including hair shafts; human beta defensin-2 and human beta defensin-3 were found in the remaining keratin layers and glands of the lower dermis; human neutrophil peptide was primarily localized to hair shafts, though visible in residual keratin layers; and LL-37 was evident in very high concentrations in the epithelium of sweat ducts. CONCLUSION: We conclude via this technique that cells in the lower dermal and subdermal regions of burned skin synthesize antimicrobials after burn injury, and maintain something of a barrier against infection. This methodology is discussed and explained in this article.

Journal Article↗
PubMed1990

[Hepatic mean transit time of 99mTc-EHIDA estimated by deconvolution analysis].

Clinical usefulness of mean transit time (MTT) through the liver was evaluated by deconvolution analysis using 99mTc-EHIDA hepatobiliary scintigraphy in 82 patients with various hepatobiliary diseases and 18 normal controls. Initial transfer factor was also obtained according to the method of Rutland. Results obtained were as follows. 1) Effect of the age on MTT was not observed in normal controls. 2) MTT in left lobe of normal controls was significantly prolonged compared with that of right lobe (P less than 0.01). This kind of difference was not observed in patients with liver cirrhosis. 3) MTT in patients with obstructive jaundice, chronic liver diseases, liver cirrhosis at decompensative state and primary biliary cirrhosis was significantly prolonged compared with that in normal controls (P less than 0.01). 4) MTT in patients with liver cirrhosis at compensative state showed normal values, although blood clearance rate in those patients was significantly decreased (P less than 0.05). 5) Positive correlation was observed between MTT and values of T-Bil, ALP, LAP, and gamma-GTP. Negative correlation was observed between MTT and value of cholinesterase. 6) Initial transfer factor correlated with blood clearance rate. (r = 0.76, P less than 0.01). 7) Initial transfer factor in left lobe of normal controls was significantly decreased compared with that of right lobe (P less than 0.01). This kind of difference was not observed in patients with liver cirrhosis. 8) Initial transfer factor in patients with liver cirrhosis in both compensative and decompensative states and PBC was significantly decreased compared with that in normal controls. Estimation of MTT and initial transfer factor could be a useful parameters to assess transfer function of the liver.

Adult↗
PubMedDate not supplied

Clinical value of deconvolution analysis in radionuclide renal study.

Deconvolution analysis was applied to radionuclide renal study. The purpose of this study was to clarify the underlying renal physiology that determines the shape and values of the transfer function. Analysis of the renal models revealed that the initial height of the transfer function is the ratio of the radioactivity extracted by the kidney to that in the input function. In addition, the shape of the transfer function displayed the distribution of the transit times and enabled us to evaluate the percentage of nephrons having a particular transit time. Based on the relation between the input and output function, a new method for measuring GFR or ERPF was developed in which the input function was corrected by the plasma radioactivity at 5 min after injection of the tracer. As one of the advantages of the transfer function, it was proved clinically that the contribution of the blood background is automatically eliminated from the amplitude of the transfer function. From these findings, our method for the measurement of GFR was considered superior to that proposed by Gates and highly useful for routine radionuclide renal study.

Glomerular Filtration Rate↗
PubMed1989

[Characterization of drug absorption from the gastrointestinal tract with the use of numeric deconvolution].

The present investigation is concerned with the absorption of drugs from the gastrointestinal tract. The duration of absorption of drugs was calculated using numerical deconvolution. Clinical data were obtained from the literature. The absorption of 36 different drugs is characterized. The results show that the duration of absorption is not uniform. Penicillins and tetracyclines are absorbed for about 3 hours after application. Most drugs are absorbed during 4 to 6 hours. A few drugs, e.g. theophylline or metoprolol, are absorbed for more than 12 hours from the gastrointestinal tract.

Humans↗
PubMed1988

Deconvolution analysis of renograms obtained with simultaneously administered 99mTc-DTPA and 131I-hippuran.

Seventy patients were studied with a dual radionuclide technique. The conventional renograms and the blood curve were subjected to deconvolution analysis using the matrix algorithm method, and the following curve data calculated from the retention functions: absolute and relative amplitudes, minimum time of the retention function, maximum time of the retention function and mean transit time. The findings with the two radiopharmaceuticals 99mTc-DTPA and 131I-Hippuran were compared under normal and pathological conditions. The correlations between the data with 99mTc-DTPA and those with 131I-Hippuran were highly significant (p less than 0.01). So was the correlation between the absolute amplitude of the retention curve and the rate of uptake based on the corresponding renogram (p less than 0.01). Due to the difference in the renal handling of the two tracers, longer maximum times were obtained with 99mTc-DTPA. The mean transit times were also longer with 99mTc-DTPA, except in kidneys with parenchymal insufficiency. The highest amplitudes were found in normal kidneys, while the lowest values were observed in parenchymal insufficiency. In the group with acute ureteral obstruction, the mean transit times tended to be increased. The maximum times were even more increased. With both tracers it is possible to distinguish between the three groups of renal conditions studied here: Normal, parenchymal insufficiency, and acute ureteral obstruction.

Acute Disease↗
PubMed1988

Evaluation of monoexponential extrapolation of transpulmonary thermal-dye kinetics by use of a new model-free deconvolution algorithm.

This study evaluates the routine mathematic approach (monoexponential extrapolation) for analysis of transpulmonary thermal-dye dilution curves and estimates the effects of systemic-indicator recirculation by use of a deconvolution technique. Fifteen dogs anesthetized with N2O-piritramid were studied before and after induction of pulmonary edema by oleic acid. After introduction of central venous indicator (10 ml of a mixture of cold blood and indocyanine green dye), dilution data were recorded from the pulmonary artery and the ascending aorta. The conclusions were: (1) monoexponential extrapolation yields reasonably good estimates of the mean transit times of dye; (2) mean transit times of heat are usually overestimated by monoexponential extrapolation; (3) extravascular lung thermal volume assessed by monoexponential extrapolation is overestimated by 2.03 ml/kg of body mass under baseline conditions; and (4) the prepulmonary volume of distribution of heat exceeds that of dye by 1.4 ml/kg of body mass, thus increasing the overestimation of pulmonary extravascular heat-accessible space by the conventional technique.

Algorithms↗
PubMed1988

Deconvoluted X-ray diffraction analysis of bone and mixtures of bone and particulate hydroxyapatite.

Recent evidence suggests that bone phosphate exists almost entirely as hydroxyapatite (HA). The relative deficiency of calcium and presence of substantial HPO2-4 in bone phosphate indicates modification of the ideal HA structure, however. An inability to resolve closely spaced lines in fine grained materials, coupled with the limited periodicity of the thin mineral crystals of bone have prevented definitive characterization of the structure of bone mineral using standard X-ray diffraction (XRD) techniques. We have applied computer deconvolution XRD techniques to aid in the resolution of component overlapped profiles from bone, synthetic hydroxyapatite (HA) and mixtures of bone and synthetic HA resulting from implantation studies. In the course of this resolution process separate profiles were resolved from the (002) profile of bone derived HA. The ratio of integrated intensities of these profiles to the intensity of the profile of synthetic HA appears to provide an approximate measure of the ratio of bone to synthetic HA in a given sample. The finding of shoulders on the (002) peak of bone provides the basis for resolution into separate profiles. The asymmetry of these shoulders in mature bone cannot be attributed to crystallinity, particle size, or computer artifact. The same finding has been previously reported in hydrolyzed, deproteinated bone. Further work will be needed to resolve the question of whether the structural heterogeneity implied by profile geometry is the result of multiple HA phases, surface layer structure involving hydrolysis and calcium absences, or some other factor.

Animals↗
PubMed1987

Deconvolution at steady state: determination of gastrointestinal bioavailability of sustained release theophylline.

A method is presented which enables the rate and extent of gastrointestinal release to be evaluated at steady state. The method requires a solution of the drug to be given orally as a reference in the same subject receiving the test product. The special mathematical and numerical aspect of the method is discussed. The method which makes use of the previously published deconvolution computer program DCON is demonstrated by evaluating the gastrointestinal release of a theophylline sustained release product at steady state.

Biological Availability↗
PubMed1986

Vitreous fluorophotometer data analysis by deconvolution.

The measurement process in fluorophotometry inherently involves a loss of information due to the finite sampling volume of the instrument. Mathematically, the effect is expressed as a convolution of the actual fluorescein distribution with the spread function of the instrument. Scattering by the ocular media can increase the spread function over that due to the instrument alone. A method is proposed for deconvolution of vitreous fluorophotometry data. Simulation studies and analyses of patient data demonstrate recovery of information with this method, including enhancement of retinal peaks and resolution of detail in the posterior vitreous which was not apparent from the original scans.

Data Display↗
PubMed1979

[Evaluation of isotope nephrograms by the deconvolution method (author's transl)].

By means of deconvolution, which can be preformed simply with a minicomputer, a new function is derived from the circulation activity time function and the renal activity time function. This function describes the impulse response of the system "Kidney". The activity time functions are determined with a four-probe counter. The impulse response allows statements about the time during which the activity remains in the kidney, the relative blood flow of both kidneys and a so-called passage time distribution. It was also attempted to substitute the circulation activity time function by a derivative of the bladder activity time function.

Humans↗
PubMed1981

Radionuclide quantitation of left-to right cardiac shunts using deconvolution analysis: concise communication.

Quantitative radionuclide angiocardiography (QRAC) was performed with and without deconvolution analysis (DA) in 87 children with various heart disorders. QRAC shunt quantitation was possible without DA in 70% of the cases and with DA in 95%. Among 21 patients with prolonged bolus injections, quantitation of the shunt was possible in 52% of the cases without DA an in all cases with DA. Correlation between oximetry and QRAC with DA was better than between oximetry and QRAC without DA. It is concluded that QRAC with DA is a more reliable, noninvasive means for detection and quantitation of left-to-right cardiac shunts than QRAC without DA.

Adolescent↗
PubMed1995

Toward fully automated genotyping: genotyping microsatellite markers by deconvolution.

Dense genetic linkage maps have been constructed for the human and mouse genomes, with average densities of 2.9 cM and 0.35 cM, respectively. These genetic maps are crucial for mapping both Mendelian and complex traits and are useful in clinical genetic diagnosis. Current maps are largely comprised of abundant, easily assayed, and highly polymorphic PCR-based microsatellite markers, primarily dinucleotide (CA)n repeats. One key limitation of these length polymorphisms is the PCR stutter (or slippage) artifact that introduces additional stutter bands. With two (or more) closely spaced alleles, the stutter bands overlap, and it is difficult to accurately determine the correct alleles; this stutter phenomenon has all but precluded full automation, since a human must visually inspect the allele data. We describe here novel deconvolution methods for accurate genotyping that mathematically remove PCR stutter artifact from microsatellite markers. These methods overcome the manual interpretation bottleneck and thereby enable full automation of genetic map construction and use. New functionalities, including the pooling of DNAs and the pooling of markers, are described that may greatly reduce the associated experimentation requirements.

Algorithms↗
PubMed1995

Viscosity comparisons of polydimethylsiloxane lubricants in latex condom brands via Fourier self-deconvolution of their FT-IR spectra.

Many brands of latex condoms use a polydimethylsiloxane lubricant. The lubricant viscosity in ten different brands was compared by determining the average chain length through the ratio of the dimethyl to trimethyl peak area obtained after applying the resolution enhancement technique of Fourier self-deconvolution to their diffuse reflectance FT-IR spectra in the area around 800 cm-1.

Condoms↗
PubMed1994

Deconvolution analysis of renal blood flow: evaluation of postrenal transplant complications.

UNLABELLED: Medical complications after renal transplantation cause problems in treatment decision making. To differentiate acute tubular necrosis from acute rejection when it occurs in the early posttransplant period is difficult. Renal scintigraphy offers a noninvasive means for renal blood flow (RBF) and renal function assessment. METHODS: This retrospective study of RBF and renal function evaluation after kidney transplantation is an attempt to calculate the "renal vascular transit time" from the 99mTc-diethylenetriaminepentaaacetic acid renal vascular flow with a deconvolution technique. The results of 102 studies on 38 graft recipients were evaluated. Of these, 19 were diagnosed as acute rejection, 12 as acute tubular necrosis, 4 as chronic rejection, 1 as vesicoureteric reflux, 1 as recurrent immunoglobulin A nephropathy, 1 as iliac vein thrombosis, 1 as cyclosporine nephrotoxicity and 63 as normal. All diagnoses were established by clinical and/or pathologic criteria. RESULTS: With renal vascular transit times more than 12.8 secm the sensitivity and specificity for the detection of acute rejection was 95% and 94%, respectively. The sensitivity and specificity for the differential diagnosis of acute rejection against acute tubular necrosis was 95% and 92%, respectively. CONCLUSION: The use of renal vascular transit time in addition to 131I-labeled hippuran renogram provides a promising diagnostic parameter to differentiate between acute rejection and acute tubular necrosis.

Adult↗
PubMed1998

Accuracy of nuclear classification in cervical smear images. Quantitative impact of computational deconvolution and 3-D feature computation.

OBJECTIVE: To investigate the accuracy with which the nuclei of cells in overlapped and thick clusters in cervical/ vaginal smears can be classified independent of the segmentation algorithm used and to determine the influence of three-dimensional (3-D) processing as compared to two-dimensional (2-D) methods on classification of the nuclei. STUDY DESIGN: Cell clusters were imaged from 31 ThinPrep smears composed of 808 nuclei, of which 420 were determined to be abnormal by a cytotechnologist. Sets of 2-D and 3-D volumetric features of the detected nuclei were formulated, and classifiers were constructed. The effect of computational deconvolution on classification was assessed using nearest-neighbor and Wiener filter in 2-D and 3-D before calculating features. A "best focus plane" was calculated for each nucleus from the 3-D data set, and the 2-D features in this plane were also analyzed.

Algorithms↗
PubMed2026

Palaeoproteomic Deconvolution of Physical and Genetic Collagen Mixtures.

Species identification in palaeoproteomics relies on genome-derived protein sequences which are often poor-quality, and lacks tools to cope with multi-species samples. Here, we address both challenges through the analysis of "physical and genetic mixtures". Species that are absent from our database are considered a "genetic mixture", i.e. a patchwork of peptides from closely related species. Inversely, various overlapping peptide stretches allow us to resolve complex "physical mixtures". This is benchmarked by analysing physical mixtures of modern bone fragments, including genetic mixtures. We illustrate the impact of our approach via a rapid and high-throughput analysis of >2500 bone fragments, revealing the Eemian-era faunal environment around Scladina Cave, including the first Palaeoloxodon antiquus identified at this site.

bioarchaeology↗