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Sample records for infarct volume estimation

  1. Prediction of final infarct volume on subacute MRI by quantifying cerebral edema in ischemic stroke.

    PubMed

    Tipirneni-Sajja, Aaryani; Christensen, Soren; Straka, Matus; Inoue, Manabu; Lansberg, Maarten G; Mlynash, Michael; Bammer, Roland; Parsons, Mark W; Donnan, Geoffrey A; Davis, Stephen M; Albers, Gregory W

    2016-01-01

    Final infarct volume in stroke trials is assessed on images obtained between 30 and 90 days after stroke onset. Imaging at such delayed timepoints is problematic because patients may be lost to follow-up or die before the scan. Obtaining an early assessment of infarct volume on subacute scans avoids these limitations; however, it overestimates true infarct volume because of edema. The aim of this study was to develop a novel approach to quantify edema so that final infarct volumes can be approximated on subacute scans. We analyzed data from 20 stroke patients (median age, 75 years) who had baseline, subacute (fu5d) and late (fu90d) MRI scans. Edema displaces CSF from sulci and ventricles; therefore, edema volume was estimated as change in CSF volume between baseline and spatially coregistered fu5d ADC maps. The median (interquartile range, IQR) estimated edema volume was 13.3 (7.5-37.7) mL. The fu5d lesion volumes correlated well with fu90d infarct volumes with slope: 1.24. With edema correction, fu5d infarct volumes are in close agreement, slope: 0.97 and strongly correlated with actual fu90d volumes. The median (IQR) difference between actual and predicted infarct volumes was 0.1 (-3.0-5.7) mL. In summary, this novel technique for estimation of edema allows final infarct volume to be predicted from subacute MRI.

  2. Infarct volume after glioblastoma surgery as an independent prognostic factor

    PubMed Central

    Bette, Stefanie; Wiestler, Benedikt; Kaesmacher, Johannes; Huber, Thomas; Gerhardt, Julia; Barz, Melanie; Delbridge, Claire; Ryang, Yu-Mi; Ringel, Florian; Zimmer, Claus; Meyer, Bernhard; Boeckh-Behrens, Tobias; Kirschke, Jan S.; Gempt, Jens

    2016-01-01

    Postoperative ischemia is associated with reduced functional independence measured by karnofsky performance score (KPS), which correlates well with overall survival. Other studies suggest that postoperative hypoxia might initiate infiltrative tumor growth. Therefore, aim of this study was to analyze the impact of infarct volume on overall survival and progression free survival (PFS) of glioblastoma patients. 251 patients with surgery for a newly diagnosed glioblastoma (WHO IV) were retrospectively assessed. Pre- and postoperative KPS, date of death/last follow-up and histopathological markers were recorded. Pre- and postoperative tumor volume and the volume of postoperative infarction were manually segmented. A significant correlation of infarct volume with postoperative KPS decrease (P = 0.001) was observed. Infarct volume showed a significant impact on overall survival (P = 0.014), but not on PFS (P = 0.112) in univariate analysis. This effect increased in the subgroup of patients with near-total tumor resection (> 90%) (overall survival: P = 0.006, PFS: P = 0.066). Infarct volume remained as an independent prognostic factor for overall survival in multivariate analysis (HR 1.013 [1.000–1.026], P = 0.042) including other prognostic factors (age, extent of resection, postoperative KPS). Postoperative infarct volume significantly correlates as an independent factor with overall survival after glioblastoma surgery. Besides the influence of perioperative infarction on postoperative KPS, postoperative hypoxia might also have an effect on tumor biology initiating infiltrative growth and therefore impaired survival. PMID:27566556

  3. Estimation of infarct size by myocardial emission computed tomography with thallium-201 and its relation to creatine kinase-MB release after myocardial infarction in man

    SciTech Connect

    Tamaki, S.; Nakajima, H.; Murakami, T.

    1982-11-01

    Emission computed tomography (ECT) for thallium-201 (/sup 201/Tl) myocardial imaging was evaluated in estimating infarct size (IS). In 18 patients in whom IS was estimated enzymatically at the time of the acute episode, planar /sup 201/Tl perfusion scintigraphy and ECT with a rotating gamma camera were performed 4 weeks after the first myocardial infarction. From the size of /sup 201/Tl perfusion defects, the infarct area in planar images and the infarct volume in reconsturcted ECT images were measured by computerized planimetry. When scintigraphic IS was compared with the accumulated creatine kinase-MB isoenzyme release (CK-MBr), infarct volume determined from ECT correlated closely with CK-MBr (r=0.89), whereas infarct area measured from planar images correlated less satisfactorily with the enzymatic IS (for an average infarct area from three views, r=0.69; for the largest infarct area, r=0.73). Although conventional scintigraphic evaluation is useful for detecting and localizing infarction, quantification of ischemic injury with this two-dimensional technique has a significant inherent limitation. The ECT approach can provide a more accurate three-dimensional quantitative estimate of infarction, and can corroborate the enzymatic estimate of IS.

  4. Estimation of infarct size by myocardial emission computed tomography with /sup 201/Tl and its relation to creatine kinase-MB release after myocardial infarction in man

    SciTech Connect

    Tamaki, S.; Nakajima, H.; Murakami, T.

    1982-11-01

    We evaluated emission computed tomography (ECT) /sup 201/Tl myocardial imaging in estimating infarct size (IS). In 18 patients in whom IS was estimated enzymatically at the time of the acute episode, planar /sup 201/Tl perfusion scintigraphy and ECT with a rotating gamma camera were performed 4 weeks after the first myocardial infarction. From the size of /sup 201/Tl perfusion defects, the infarct area in planar images and the infarct volume in reconstructed ECT images were measured by computerized planimetry. When scintigraphic IS was compared with the accumulated creatine kinase-MB isoenzyme release (CK-MBr), infarct volume determined from ECT correlated closely with CK-MBr (r . 0.89), whereas infarct area measured from planar images correlated less satisfactorily with the enzymatic IS (for an average infarct area from three views, r . 0.69; for the largest infarct area, r . 0.73). Although conventional scintigraphic evaluation is useful for detecting and localizing infarction, quantification of ischemic injury with this two-dimensional technique has a significant inherent limitation. The ECT approach can provide a more accurate three-dimensional quantitative estimate of infarction, and can corroborate the enzymatic estimate of IS.

  5. Comparison of radionuclide and enzymatic estimate of infarct size in patients with acute myocardial infarction

    SciTech Connect

    Hirsowitz, G.S.; Lakier, J.B.; Marks, D.S.; Lee, T.G.; Goldberg, A.D.; Goldstein, S.

    1983-06-01

    A comparison was made of the estimated size of the myocardial infarction occurring in 26 patients with a first infarction using creatine kinase (CK) enzyme release between radionuclide gated blood pool measurement of total and regional ventricular function and thallium-201 scintigraphic measurement of myocardial perfusion defects. Creatine kinase estimates of infarct size (enzymatic infarct size) correlated closely with the percent of abnormal contracting regions, left ventricular ejection fraction and thallium-201 estimates of percent of abnormal perfusion area (r . 0.78, 0.69 and 0.74, respectively, p less than 0.01). A close correlation also existed between percent abnormal perfusion area and percent of abnormal contracting regions (r . 0.81, p less than 0.01) and left ventricular ejection fraction (r . 0.69, p less than 0.01). Enzymatic infarct size was larger in anterior (116 +/- 37 CK-g-Eq) than inferior (52 +/- 29 CK-g-Eq) myocardial infarction (p less than 0.01) and was associated with significantly more left ventricular functional impairment as determined by left ventricular ejection fraction (33 +/- 7 versus 60 +/- 10%) (p less than 0.01) and percent abnormal perfusion area (58 +/- 14 versus 13 +/- 12) (p less than 0.01). No significant correlation was observed between enzymatic infarct size and right ventricular ejection fraction. These different methods of estimating infarct size correlated closely with each other in these patients with a first uncomplicated myocardial infarction.

  6. Direct volume estimation without segmentation

    NASA Astrophysics Data System (ADS)

    Zhen, X.; Wang, Z.; Islam, A.; Bhaduri, M.; Chan, I.; Li, S.

    2015-03-01

    Volume estimation plays an important role in clinical diagnosis. For example, cardiac ventricular volumes including left ventricle (LV) and right ventricle (RV) are important clinical indicators of cardiac functions. Accurate and automatic estimation of the ventricular volumes is essential to the assessment of cardiac functions and diagnosis of heart diseases. Conventional methods are dependent on an intermediate segmentation step which is obtained either manually or automatically. However, manual segmentation is extremely time-consuming, subjective and highly non-reproducible; automatic segmentation is still challenging, computationally expensive, and completely unsolved for the RV. Towards accurate and efficient direct volume estimation, our group has been researching on learning based methods without segmentation by leveraging state-of-the-art machine learning techniques. Our direct estimation methods remove the accessional step of segmentation and can naturally deal with various volume estimation tasks. Moreover, they are extremely flexible to be used for volume estimation of either joint bi-ventricles (LV and RV) or individual LV/RV. We comparatively study the performance of direct methods on cardiac ventricular volume estimation by comparing with segmentation based methods. Experimental results show that direct estimation methods provide more accurate estimation of cardiac ventricular volumes than segmentation based methods. This indicates that direct estimation methods not only provide a convenient and mature clinical tool for cardiac volume estimation but also enables diagnosis of cardiac diseases to be conducted in a more efficient and reliable way.

  7. Estimating volume from stump measurements

    Treesearch

    Kenneth L. Quigley

    1954-01-01

    Foresters sometimes have to estimate the volume of timber harvested from the stumps that remain after logging. Such estimates may be needed when the timber cutters have crossed property lines or when they have removed trees not marked for cutting. Stump measurements on sample areas may also be used for state or regional estimates of the volume of timber cut annually,...

  8. Quantification of infarct size by /sup 201/Tl single-photon emission computed tomography during acute myocardial infarction in humans. Comparison with enzymatic estimates

    SciTech Connect

    Mahmarian, J.J.; Pratt, C.M.; Borges-Neto, S.; Cashion, W.R.; Roberts, R.; Verani, M.S.

    1988-10-01

    We prospectively investigated whether /sup 201/Tl single-photon emission computed tomography (SPECT) could accurately diagnose the presence and quantify the extent of acute myocardial infarction when compared with infarct size assessed by plasma MB-creatine kinase activity. Thirty patients with enzymatic evidence of infarction were imaged within 12-36 hours of chest pain (mean, 23.4 hours). No patient had a previous infarction, and none underwent intervention seeking to restore coronary patency. Infarct size was quantified with computer-generated polar maps of the myocardial radioactivity and expressed as a percentage of the total left ventricular volume. To assess left and right ventricular performance, blood-pool gated radionuclide angiography was performed immediately after SPECT. All 30 patients had perfusion defects consistent with myocardial infarction. Scintigraphic and enzymatic estimates of infarct size correlated well for the group as a whole (r = 0.78, p less than 0.001, SEE = 9.1) but especially for those patients with anterior infarction (r = 0.91, p less than 0.001, SEE = 7.9). The poor correlation observed in patients with inferior infarction (r = 0.50, p less than 0.05, SEE = 10.0) was believed to be related to the frequent occurrence of right ventricular involvement because SPECT assessed only left ventricular damage, whereas the enzymatic method estimated the myocardial injury in both ventricles. A quantitative index of right ventricular infarct size, derived from the relation between the scintigraphic and enzymatic estimates, had a strong inverse correlation with right ventricular ejection fraction (r = -0.89, p less than 0.001, SEE = 3.6).

  9. Age estimation from canine volumes.

    PubMed

    De Angelis, Danilo; Gaudio, Daniel; Guercini, Nicola; Cipriani, Filippo; Gibelli, Daniele; Caputi, Sergio; Cattaneo, Cristina

    2015-08-01

    Techniques for estimation of biological age are constantly evolving and are finding daily application in the forensic radiology field in cases concerning the estimation of the chronological age of a corpse in order to reconstruct the biological profile, or of a living subject, for example in cases of immigration of people without identity papers from a civil registry. The deposition of teeth secondary dentine and consequent decrease of pulp chamber in size are well known as aging phenomena, and they have been applied to the forensic context by the development of age estimation procedures, such as Kvaal-Solheim and Cameriere methods. The present study takes into consideration canines pulp chamber volume related to the entire teeth volume, with the aim of proposing new regression formulae for age estimation using 91 cone beam computerized scans and a freeware open-source software, in order to permit affordable reproducibility of volumes calculation.

  10. Organ volume estimation using SPECT

    SciTech Connect

    Zaidi, H.

    1996-06-01

    Knowledge of in vivo thyroid volume has both diagnostic and therapeutic importance and could lead to a more precise quantification of absolute activity contained in the thyroid gland. In order to improve single-photon emission computed tomography (SPECT) quantitation, attenuation correction was performed according to Chang`s algorithm. The dual window method was used for scatter subtraction. The author used a Monte Carlo simulation of the SPECT system to accurately determine the scatter multiplier factor k. Volume estimation using SPECT was performed by summing up the volume elements (voxels) lying within the contour of the object, determined by a fixed threshold and the gray level histogram (GLH) method. Thyroid phantom and patient studies were performed and the influence of (1) fixed thresholding, (2) automatic thresholding, (3) attenuation, (4) scatter, and (5) reconstruction filter were investigated. This study shows that accurate volume estimation of the thyroid gland is feasible when accurate corrections are performed. The relative error is within 7% for the GLH method combined with attenuation and scatter corrections.

  11. An improved automated method to quantitate infarct volume in triphenyltetrazolium stained rat brain sections.

    PubMed

    Regan, Hillary K; Detwiler, Theodore J; Huang, Judy C; Lynch, Joseph J; Regan, Christopher P

    2007-01-01

    The identification of acute neuroprotectants relies heavily on rodent stroke models. It is well know that some of the more common models used can exhibit a relatively high degree of inter animal variability. This necessitates the need to increase the sample size per group and to run concomitant positive and negative control groups with each study in order to increase the consistency and reproducibility of the model. As such, one aspect of these studies that has become more labor intensive is the measurement of infarct volume post study. Herein, we describe a simple method to determine stroke infarct volume in triphenyltetrazolium (TTC) stained brain sections utilizing an automated set of routines using standard software. The method was first validated by determining the correlation of infarct volumes derived from the manual measurements vs the automated method for the same samples across a wide range of infarcts. This comparison resulted in a significant correlation (r=0.99) indicating that the automated method was a valid method to assess infarct volume across a wide range in lesion volumes. Next, the automated infarct analysis tool was used to determine the effect of (+)-MK801, a well known neuroprotectant, on infarct volume after cerebral ischemia. This study demonstrated a significant reduction in infarct volume in (+)-MK801 treated rats. These data demonstrate a simple, accurate automated routine to measure lesion volume in TTC stained sections.

  12. Quantitative estimation of infarct size by simultaneous dual radionuclide single photon emission computed tomography: comparison with peak serum creatine kinase activity

    SciTech Connect

    Kawaguchi, K.; Sone, T.; Tsuboi, H.; Sassa, H.; Okumura, K.; Hashimoto, H.; Ito, T.; Satake, T. )

    1991-05-01

    To test the hypothesis that simultaneous dual energy single photon emission computed tomography (SPECT) with technetium-99m (99mTc) pyrophosphate and thallium-201 (201TI) can provide an accurate estimate of the size of myocardial infarction and to assess the correlation between infarct size and peak serum creatine kinase activity, 165 patients with acute myocardial infarction underwent SPECT 3.2 +/- 1.3 (SD) days after the onset of acute myocardial infarction. In the present study, the difference in the intensity of 99mTc-pyrophosphate accumulation was assumed to be attributable to difference in the volume of infarcted myocardium, and the infarct volume was corrected by the ratio of the myocardial activity to the osseous activity to quantify the intensity of 99mTc-pyrophosphate accumulation. The correlation of measured infarct volume with peak serum creatine kinase activity was significant (r = 0.60, p less than 0.01). There was also a significant linear correlation between the corrected infarct volume and peak serum creatine kinase activity (r = 0.71, p less than 0.01). Subgroup analysis showed a high correlation between corrected volume and peak creatine kinase activity in patients with anterior infarctions (r = 0.75, p less than 0.01) but a poor correlation in patients with inferior or posterior infarctions (r = 0.50, p less than 0.01). In both the early reperfusion and the no reperfusion groups, a good correlation was found between corrected infarct volume and peak serum creatine kinase activity (r = 0.76 and r = 0.76, respectively; p less than 0.01).

  13. Renal infarct volume and renal function decline in acute and chronic phases.

    PubMed

    Kagaya, Saeko; Yoshie, Ojima; Fukami, Hirotaka; Sato, Hiroyuki; Saito, Ayako; Takeuchi, Yoichi; Matsuda, Ken; Nagasawa, Tasuku

    2017-03-10

    Acute renal infarction (ARI) is a rare disease. ARI causes decline in renal function in both the acute and chronic phases. However, the correlation between the volume of the infarction and degree of renal function decline has not been fully investigated. Therefore, we aimed to examine the relationship between the volume of the infarction and degree of renal function decline. We performed a single-center, retrospective, observational study investigating clinical parameters and the volume of the infarction. The volume of the infarction was measured using reconstructed computed tomography data. A total of 39 patients (mean age, 72.6 ± 13.2 years; men, 59%) were enrolled. The median infarction volume was 45 mL (interquartile range, 14-91 mL). The volume of the infarction was significantly associated with the peak lactate dehydrogenase (LDH) level (median, 728 IU/L; interquartile range, 491-1227 U/L) (r = 0.58, p < 0.01) and the degree of renal function decline in both acute and chronic phases (r = -0.44, -0.38, respectively, p < 0.05). The peak LDH level was significantly correlated with the degree of renal function decline in the acute phase but not in the chronic phase (r = -0.35, -0.21; p < 0.05, N.S., respectively). The volume of the infarction may be a factor in the degree of renal function decline in ARI. Therefore, assessment of infarct volume in ARI is important.

  14. A novel genetic locus modulates infarct volume independently of the extent of collateral circulation.

    PubMed

    Chu, Pei-Lun; Keum, Sehoon; Marchuk, Douglas A

    2013-09-03

    In the mouse model of permanent, middle cerebral artery occlusion, infarct volume varies widely across inbred strains but generally is inversely correlated with collateral vessel number. However, we also observed certain mouse strains that share similar collateral vessel anatomy but exhibit significantly different infarct volume. To identify genetic factors determining infarct volume in a collateral vessel-independent manner, we performed quantitative trait locus analysis on a F2 cross between C57BL/6J and C3H/HeJ strains. We mapped four novel loci (Civq4 through Civq7) that modulate infarct volume. Civq4, on chromosome 8, is the strongest locus (logarithm of the odds 9.8) that contributes 21% of the phenotypic variance of infarct volume in the cross. The Civq4 and Civq6 loci represent transgressive B6 alleles that render animals susceptible to larger infarcts. Based on genomic sequence and microarray analyses, we propose candidate genes for the Civq4 locus. By selecting inbred strains with similar collateral vessel anatomy but that vary significantly in infarct volume, we have mapped four loci determining infarct volume in a mouse model of ischemic stroke. Two of the loci appear to modulate infarct volume through a collateral vessel-independent mechanism. Based on strain-specific sequence variants and differences in transcript levels, Msr1 and Mtmr7 appear to be strong candidate genes for Civq4. Identifying the underlying genetic factors of these loci will elucidate the genetic architecture response to cerebral ischemia, shed new light on disease mechanisms of ischemic stroke, and identify potential therapeutic targets for clinical applications.

  15. A novel genetic locus modulates infarct volume independently of the extent of collateral circulation

    PubMed Central

    Chu, Pei-Lun; Keum, Sehoon

    2013-01-01

    In the mouse model of permanent, middle cerebral artery occlusion, infarct volume varies widely across inbred strains but generally is inversely correlated with collateral vessel number. However, we also observed certain mouse strains that share similar collateral vessel anatomy but exhibit significantly different infarct volume. To identify genetic factors determining infarct volume in a collateral vessel-independent manner, we performed quantitative trait locus analysis on a F2 cross between C57BL/6J and C3H/HeJ strains. We mapped four novel loci (Civq4 through Civq7) that modulate infarct volume. Civq4, on chromosome 8, is the strongest locus (logarithm of the odds 9.8) that contributes 21% of the phenotypic variance of infarct volume in the cross. The Civq4 and Civq6 loci represent transgressive B6 alleles that render animals susceptible to larger infarcts. Based on genomic sequence and microarray analyses, we propose candidate genes for the Civq4 locus. By selecting inbred strains with similar collateral vessel anatomy but that vary significantly in infarct volume, we have mapped four loci determining infarct volume in a mouse model of ischemic stroke. Two of the loci appear to modulate infarct volume through a collateral vessel-independent mechanism. Based on strain-specific sequence variants and differences in transcript levels, Msr1 and Mtmr7 appear to be strong candidate genes for Civq4. Identifying the underlying genetic factors of these loci will elucidate the genetic architecture response to cerebral ischemia, shed new light on disease mechanisms of ischemic stroke, and identify potential therapeutic targets for clinical applications. PMID:23800850

  16. Estimating sugar maple bark thickness and volume.

    Treesearch

    Charles L. Stayton; Michael Hoffman

    1970-01-01

    Sugar maple bark thickness and volume were estimated using first a published method, then equations developed by the authors. Both methods gave estimates that compared closely with measured values. Information is also presented on variation in bark thickness and on weight and volume of bark as a percentage of total merchantable stem weight and volume.

  17. Mean platelet volume and cardiovascular outcomes in acute myocardial infarction

    PubMed Central

    Ranjith, Mangalachulli Pottammal; DivyaRaj, Rajendran; Mathew, Dolly; George, Biju; Krishnan, Mangalath Narayanan

    2016-01-01

    Objective High levels of mean platelet volume (MPV) may be associated with adverse outcomes in patients with myocardial infarction (MI). We examined the association between MPV and the risk of death and adverse cardiovascular outcomes in patients with MI. Methods We studied consecutive patients with MI admitted to a tertiary-care hospital during a period of 1 year. MPV was measured at admission and at third month. Patients were followed up for 1-year primary composite outcome of cardiovascular death, stroke, fatal or non-fatal MI and cardiac failure. Patients were classified according to tertile of baseline MPV. Results A total of 1206 patients with MI, including 934 men (77.4%) and 272 women (22.6%) were studied. The mean age of the study population was 56 years. At 1-year follow-up, 292 (28.57%) primary outcome occurred: cardiovascular mortality 78 (7.6%), fatal or non-fatal MI 153 (15.0%), stroke 30 (2.9%) and cardiac failure 128 (12.52%). Patients with the highest tertile MPV had higher primary outcome as compared with those with MPV in the lowest tertile (adjusted OR=2.31; 95% CI 1.60 to 3.35; p<0.001). Total mortality was also more in high-MPV group (adjusted OR 2.62; 95% CI 1.47 to 4.70; p<0.001). There were no significant changes in mean MPV values at admission from those at third month interval (9.15, (SD 0.99) vs 9.19 (SD 0.94); p=0.2). Conclusions Elevated MPV was associated with worse outcome in patients with acute MI. Elevated MPV in these patients may be due to inherently large platelets. Trial registration number http://ctri.nic.in/Clinicaltrials/rmaindet.php?trialid=5485&EncHid=98036.61144&modid=1&compid=19; CTRI/2012/12/003222. PMID:27326224

  18. Mean platelet volume and cardiovascular outcomes in acute myocardial infarction.

    PubMed

    Ranjith, Mangalachulli Pottammal; DivyaRaj, Rajendran; Mathew, Dolly; George, Biju; Krishnan, Mangalath Narayanan

    2016-01-01

    High levels of mean platelet volume (MPV) may be associated with adverse outcomes in patients with myocardial infarction (MI). We examined the association between MPV and the risk of death and adverse cardiovascular outcomes in patients with MI. We studied consecutive patients with MI admitted to a tertiary-care hospital during a period of 1 year. MPV was measured at admission and at third month. Patients were followed up for 1-year primary composite outcome of cardiovascular death, stroke, fatal or non-fatal MI and cardiac failure. Patients were classified according to tertile of baseline MPV. A total of 1206 patients with MI, including 934 men (77.4%) and 272 women (22.6%) were studied. The mean age of the study population was 56 years. At 1-year follow-up, 292 (28.57%) primary outcome occurred: cardiovascular mortality 78 (7.6%), fatal or non-fatal MI 153 (15.0%), stroke 30 (2.9%) and cardiac failure 128 (12.52%). Patients with the highest tertile MPV had higher primary outcome as compared with those with MPV in the lowest tertile (adjusted OR=2.31; 95% CI 1.60 to 3.35; p<0.001). Total mortality was also more in high-MPV group (adjusted OR 2.62; 95% CI 1.47 to 4.70; p<0.001). There were no significant changes in mean MPV values at admission from those at third month interval (9.15, (SD 0.99) vs 9.19 (SD 0.94); p=0.2). Elevated MPV was associated with worse outcome in patients with acute MI. Elevated MPV in these patients may be due to inherently large platelets. http://ctri.nic.in/Clinicaltrials/rmaindet.php?trialid=5485&EncHid=98036.61144&modid=1&compid=19; CTRI/2012/12/003222.

  19. Comparison of Perfusion CT Software to Predict the Final Infarct Volume After Thrombectomy.

    PubMed

    Austein, Friederike; Riedel, Christian; Kerby, Tina; Meyne, Johannes; Binder, Andreas; Lindner, Thomas; Huhndorf, Monika; Wodarg, Fritz; Jansen, Olav

    2016-09-01

    Computed tomographic perfusion represents an interesting physiological imaging modality to select patients for reperfusion therapy in acute ischemic stroke. The purpose of our study was to determine the accuracy of different commercial perfusion CT software packages (Philips (A), Siemens (B), and RAPID (C)) to predict the final infarct volume (FIV) after mechanical thrombectomy. Single-institutional computed tomographic perfusion data from 147 mechanically recanalized acute ischemic stroke patients were postprocessed. Ischemic core and FIV were compared about thrombolysis in cerebral infarction (TICI) score and time interval to reperfusion. FIV was measured at follow-up imaging between days 1 and 8 after stroke. In 118 successfully recanalized patients (TICI 2b/3), a moderately to strongly positive correlation was observed between ischemic core and FIV. The highest accuracy and best correlation are shown in early and fully recanalized patients (Pearson r for A=0.42, B=0.64, and C=0.83; P<0.001). Bland-Altman plots and boxplots demonstrate smaller ranges in package C than in A and B. Significant differences were found between the packages about over- and underestimation of the ischemic core. Package A, compared with B and C, estimated more than twice as many patients with a malignant stroke profile (P<0.001). Package C best predicted hypoperfusion volume in nonsuccessfully recanalized patients. Our study demonstrates best accuracy and approximation between the results of a fully automated software (RAPID) and FIV, especially in early and fully recanalized patients. Furthermore, this software package overestimated the FIV to a significantly lower degree and estimated a malignant mismatch profile less often than other software. © 2016 American Heart Association, Inc.

  20. Predictive Value of Pooled Cerebral Blood Volume Mapping for Final Infarct Volume in Patients with Major Artery Occlusions. A Retrospective Analysis.

    PubMed

    Ava, Lauma; Berkefeld, Joachim; Lauer, Arne; Seiler, Alexander; Pfeilschifter, Waltraud; Müller-Eschner, Monika; You, Se-Jong; Weidauer, Stefan; Pilatus, Ulrich; Wagner, Marlies

    2017-03-13

    Detection of ischemic core and collateral status is helpful to predict clinical success of thrombectomy in acute cerebral artery occlusion. Angiographic flat panel detector computed tomography (CT) with pooled blood volume (PBV) data acquisition was described to be helpful to estimate ischemic core in stroke patients prior to thrombectomy and to depict cerebral vessels. We therefore retrospectively evaluated preinterventional PBV data of a large collective of ischemic stroke patients prior to thrombectomy to test its predictive value on final infarct considering PBV maps and collateral status. We used PBV data from 101 patients with acute cerebral artery occlusion prior to successful thrombectomy to reconstruct PBV maps and collateral status maps. Suspected ischemic core and collateral status were correlated to final infarct on follow-up multislice CT. Furthermore, the influence of time window and patient age was taken into consideration. In 75.2% (95% confidence interval CI 66-82%), suspected ischemic core (PBV) matched with final infarct and in 24.8% (95% CI 17-34%) final infarct was overestimated. In all patients, collateral status could be evaluated, and the better the collateral status, the smaller the final infarct (p = 0.016). Although not statistically significant, poor collaterals seem to be a risk factor for overestimation of final infarct on PBV maps. In patients >80 years old predictive value of PBV and collateral status is better than in patients ≤80 years old (p = 0.04). Increasing time window did not have significant impact on predictive value of PBV and collateral status. The PBV data are useful to expeditiously exclude infarct growth and estimate collateral status prior to thrombectomy after a longer interval between initial multislice CT magnetic resonance imaging (MRI) and intervention. However, because of overestimating final infarct in 25% of patients, PBV data presuming large infarct should not be used as the only basis for excluding

  1. Comparison of enzymic with cineangiocardiographic estimations of myocardial infarct size.

    PubMed Central

    Sammel, N L; Stuckey, J G; Brandt, P W; Norris, R M

    1980-01-01

    Comparisons were made between enzymic indices of myocardial infarct size (total creatine kinase appearance and peak enzyme activity) measured during the acute state of a first myocardial infarct in 32 male patients, and analysis of contraction abnormalities in biplane left ventricular cineangiocardiograms performed one month later. The cineangiocardiograms were analysed independently by two radiologists, each using two different methods for quantification of subjectively classified abnormalities of left ventricular wall motion. A very strong correlation was found between the two enzymic indices of infarct size and somewhat weaker correlations between assessment of contractility abnormalities made by the two radiologists using the same method, or by the same radiologist using the two different methods. Comparisons between enzymic and angiocardiographic indices for all infarcts showed correlation coefficients (r) within the range of 0.53 to 0.72. With all comparisons of enzymic with radiological indices r values were higher for anterior infarcts than for inferior infarcts, and there was a tendency for higher enzyme levels for a given degree of left ventricular damage in inferior than in anterior infarction. This may be the result of variable degrees of right ventricular damage in inferior infarction. PMID:7426141

  2. Relationship Between Carotid Stenosis and Infarct Volume in Ischemic Stroke Patients

    PubMed Central

    Alagöz, Aybala Neslihan; Acar, Bilgehan Atılgan; Acar, Türkan; Karacan, Alper; Demiryürek, Bekir Enes

    2016-01-01

    Background Stroke is a serious health problem all over the world. Ischemia causes 85% of strokes and 75% of these ischemic strokes occur within the area supplied by the internal carotid artery (ICA). Material/Methods This study included 47 acute stroke patients who were in the large-artery atherosclerosis group according to Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification and who had an infarct in the area supplied by the internal carotid artery. We sought to determine whether there was a significant correlation between the infarct volume of the patients as measured by diffusion-weighted magnetic resonance imaging (DW MRI), their National Institutes of Health Stroke Scale (NIHSS), and degree of carotid stenosis as identified by carotid computed tomography angiography (CTA). Results A significant correlation was observed between the percentage of carotid artery stenosis and infarct volume (p<0.001). In addition, there was a significant positive correlation between the NIHSS and infarct volume; the correlation was of moderate strength (r=0.366, p=0.001). Conclusions Our findings indicate that the percentage of carotid artery stenosis could be useful in predicting the infarct volume of the stroke. PMID:27984560

  3. Validity of shape as a predictive biomarker of final infarct volume in acute ischemic stroke.

    PubMed

    Frindel, Carole; Rouanet, Anaïs; Giacalone, Mathilde; Cho, Tae-Hee; Østergaard, Leif; Fiehler, Jens; Pedraza, Salvador; Baron, Jean-Claude; Wiart, Marlène; Berthezène, Yves; Nighoghossian, Norbert; Rousseau, David

    2015-04-01

    This study examines whether lesion shape documented on magnetic resonance diffusion-weighted imaging during acute stroke improves the prediction of the final infarct volume compared with lesion volume only. Diffusion-weighted imaging data and clinical information were retrospectively reviewed in 110 consecutive patients who underwent (n=67) or not (n=43) thrombolytic therapy for acute ischemic stroke. Three-dimensional shape analysis was performed on admission diffusion-weighted imaging data and 5 shape descriptors were developed. Final infarct volume was measured on T2-fluid-attenuated inversion recovery imaging data performed 30 days after stroke. Shape analysis of acute ischemic lesion and more specifically the ratio of the bounding box volume to the lesion volume before thrombolytic treatment improved the prediction of the final infarct for patients undergoing thrombolysis (R(2)=0.86 in model with volume; R(2)=0.98 in model with volume and shape). Our findings suggest that lesion shape contains important predictive information and reflects important environmental factors that might determine the progression of ischemia from the core. © 2015 American Heart Association, Inc.

  4. CONTAMINATED SOIL VOLUME ESTIMATE TRACKING METHODOLOGY

    SciTech Connect

    Durham, L.A.; Johnson, R.L.; Rieman, C.; Kenna, T.; Pilon, R.

    2003-02-27

    The U.S. Army Corps of Engineers (USACE) is conducting a cleanup of radiologically contaminated properties under the Formerly Utilized Sites Remedial Action Program (FUSRAP). The largest cost element for most of the FUSRAP sites is the transportation and disposal of contaminated soil. Project managers and engineers need an estimate of the volume of contaminated soil to determine project costs and schedule. Once excavation activities begin and additional remedial action data are collected, the actual quantity of contaminated soil often deviates from the original estimate, resulting in cost and schedule impacts to the project. The project costs and schedule need to be frequently updated by tracking the actual quantities of excavated soil and contaminated soil remaining during the life of a remedial action project. A soil volume estimate tracking methodology was developed to provide a mechanism for project managers and engineers to create better project controls of costs and schedule. For the FUSRAP Linde site, an estimate of the initial volume of in situ soil above the specified cleanup guidelines was calculated on the basis of discrete soil sample data and other relevant data using indicator geostatistical techniques combined with Bayesian analysis. During the remedial action, updated volume estimates of remaining in situ soils requiring excavation were calculated on a periodic basis. In addition to taking into account the volume of soil that had been excavated, the updated volume estimates incorporated both new gamma walkover surveys and discrete sample data collected as part of the remedial action. A civil survey company provided periodic estimates of actual in situ excavated soil volumes. By using the results from the civil survey of actual in situ volumes excavated and the updated estimate of the remaining volume of contaminated soil requiring excavation, the USACE Buffalo District was able to forecast and update project costs and schedule. The soil volume

  5. Troponin T: Correlation with location and volume of acute brain infarction.

    PubMed

    Král, Michal; Šaňák, Daniel; Veverka, Tomáš; Hutyra, Martin; Vindiš, David; Bártková, Andrea; Kunčarová, Anna; Dorňák, Tomáš; Čecháková, Eva; Herzig, Roman; Langová, Kateřina; Kaňovský, Petr; Školoudík, David

    2015-02-15

    The troponin T (cTnT) is frequently elevated in acute ischemic stroke (AIS) patients. However, the relationship, if any, between the cTnT level and brain infarction remains to be established. The aim was to investigate the possible correlation between the location and volume of brain infarction and the cardiac cTnT serum level in AIS patients. The study consisted of consecutive AIS patients admitted within 12h of stroke onset. The location and volume of the acute ischemic lesion was assessed with magnetic resonance imaging. Standard laboratory tests, including cTnT and repeated electrocardiograms, were performed at admission and after 4h. Correlations between the cTnT level and the location and volume of brain infarction and baseline parameters were tested with a Spearman correlation coefficient. Univariate and multiple logistic regression analysis (LRA) were used to determine the possible predictors of cTnT elevation. Out of the 200 enrolled patients, elevated cTnT was present in 71 (36%). No correlation was found between the cTnT serum levels and the location (P>0.05) nor volume of brain infarction (r=0.05, P=0.48). LRA identified creatinine (OR: 1.26 per 10μmol/L increase; 95% CI: 1.043-1.524), NT-proBNP (OR: 1.05 per 100μg/L increase; 95% CI: 1.018-1.093) and male gender (OR: 3.674; 95% CI: 1.025-13.164) as significant independent predictors of pathological elevation of cTnT. Although elevated cTnT serum level is relatively frequent in AIS patients within the first 12h of stroke onset, it is not related to the location or volume of brain infarction. http://www.clinicaltrials.gov (No. NCT01541163). Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  6. Be the Volume: A Classroom Activity to Visualize Volume Estimation

    ERIC Educational Resources Information Center

    Mikhaylov, Jessica

    2011-01-01

    A hands-on activity can help multivariable calculus students visualize surfaces and understand volume estimation. This activity can be extended to include the concepts of Fubini's Theorem and the visualization of the curves resulting from cross-sections of the surface. This activity uses students as pillars and a sheet or tablecloth for the…

  7. Be the Volume: A Classroom Activity to Visualize Volume Estimation

    ERIC Educational Resources Information Center

    Mikhaylov, Jessica

    2011-01-01

    A hands-on activity can help multivariable calculus students visualize surfaces and understand volume estimation. This activity can be extended to include the concepts of Fubini's Theorem and the visualization of the curves resulting from cross-sections of the surface. This activity uses students as pillars and a sheet or tablecloth for the…

  8. CT angiography and CT perfusion improve prediction of infarct volume in patients with anterior circulation stroke.

    PubMed

    van Seeters, Tom; Biessels, Geert Jan; Kappelle, L Jaap; van der Schaaf, Irene C; Dankbaar, Jan Willem; Horsch, Alexander D; Niesten, Joris M; Luitse, Merel J A; Majoie, Charles B L M; Vos, Jan Albert; Schonewille, Wouter J; van Walderveen, Marianne A A; Wermer, Marieke J H; Duijm, Lucien E M; Keizer, Koos; Bot, Joseph C J; Visser, Marieke C; van der Lugt, Aad; Dippel, Diederik W J; Kesselring, F Oskar H W; Hofmeijer, Jeannette; Lycklama À Nijeholt, Geert J; Boiten, Jelis; van Rooij, Willem Jan; de Kort, Paul L M; Roos, Yvo B W E M; Meijer, Frederick J A; Pleiter, C Constantijn; Mali, Willem P T M; van der Graaf, Yolanda; Velthuis, Birgitta K

    2016-04-01

    We investigated whether baseline CT angiography (CTA) and CT perfusion (CTP) in acute ischemic stroke could improve prediction of infarct presence and infarct volume on follow-up imaging. We analyzed 906 patients with suspected anterior circulation stroke from the prospective multicenter Dutch acute stroke study (DUST). All patients underwent baseline non-contrast CT, CTA, and CTP and follow-up non-contrast CT/MRI after 3 days. Multivariable regression models were developed including patient characteristics and non-contrast CT, and subsequently, CTA and CTP measures were added. The increase in area under the curve (AUC) and R (2) was assessed to determine the additional value of CTA and CTP. At follow-up, 612 patients (67.5%) had a detectable infarct on CT/MRI; median infarct volume was 14.8 mL (interquartile range (IQR) 2.8-69.6). Regarding infarct presence, the AUC of 0.82 (95% confidence interval (CI) 0.79-0.85) for patient characteristics and non-contrast CT was improved with addition of CTA measures (AUC 0.85 (95% CI 0.82-0.87); p < 0.001) and was even higher after addition of CTP measures (AUC 0.89 (95% CI 0.87-0.91); p < 0.001) and combined CTA/CTP measures (AUC 0.89 (95% CI 0.87-0.91); p < 0.001). For infarct volume, adding combined CTA/CTP measures (R (2) = 0.58) was superior to patient characteristics and non-contrast CT alone (R (2) = 0.44) and to addition of CTA alone (R (2) = 0.55) or CTP alone (R (2) = 0.54; all p < 0.001). In the acute stage, CTA and CTP have additional value over patient characteristics and non-contrast CT for predicting infarct presence and infarct volume on follow-up imaging. These findings could be applied for patient selection in future trials on ischemic stroke treatment.

  9. Infarct volume on apparent diffusion coefficient maps correlates with length of stay and outcome after middle cerebral artery stroke.

    PubMed

    Engelter, Stefan T; Provenzale, James M; Petrella, Jeffrey R; DeLong, David M; Alberts, Mark J

    2003-01-01

    Diffusion-weighted MRI (DWI) can depict acute ischemia based on decreased apparent diffusion coefficient (ADC) values. ADC maps, unlike DWI (which have contributions from T2 properties), solely reflect diffusion properties. Recent studies indicate that severity of neurological deficit corresponds with degree of ADC alteration. To determine whether infarct volume on ADC maps correlates with length of hospitalization and clinical outcome in patients with acute ischemic middle cerebral artery (MCA) stroke. Forty-five consecutive patients with acute (infarcts seen on DWI. Infarct volume was determined by counting pixels with ADC values >3 SDs below the average ADC value of a contralateral control region. Infarct volume was correlated with length of hospitalization and 6-month outcome assessed with Glasgow Outcome Scale (GOS), Modified Rankin Score (mRS), Barthel Index (BI) and a dichotomized outcome status with favorable outcome defined as GOS 1, mRS or=95. Infarct volume on ADC maps ranged from 0.2 to 187 cm(3) and was significantly correlated with length of hospitalization (p < 0.001, r = 0.67). Furthermore, ADC infarct volume was significantly correlated with GOS (r = 0.73), mRS (r = 0.68), BI (r = 0.67) and outcome status (r = 0.65) (each p < 0.001). Multiple logistic regression revealed a statistically significant correlation between ADC infarct volume and outcome status (p < 0.05), but none for Canadian Neurological Scale score, age and gender (p >0.05 each). Infarct volume measured by using a quantitative definition for infarcted tissue on ADC maps correlated significantly with length of hospitalization (as a possible surrogate marker for short-term outcome) and functional outcome after 6 months. ADC infarct volume may provide prognostic information for patients with acute ischemic MCA stroke. Copyright 2003 S. Karger AG, Basel

  10. Diffusion tensor imaging correlates with lesion volume in cerebral hemisphere infarctions.

    PubMed

    Rossi, Maija E; Jason, Eeva; Marchesotti, Silvia; Dastidar, Prasun; Ollikainen, Jyrki; Soimakallio, Seppo

    2010-09-17

    Both a large lesion volume and abnormalities in diffusion tensor imaging are independently associated with a poor prognosis after cerebral infarctions. Therefore, we assume that they are associated. This study assessed the associations between lesion volumes and diffusion tensor imaging in patients with a right-sided cerebral infarction. The lesion volumes of 33 patients (age 65.9 ± 8.7, 26 males and 7 females) were imaged using computed tomography (CT) in the acute phase (within 3-4 hours) and magnetic resonance imaging (MRI) in the chronic phase (follow-up at 12 months, with a range of 8-27 months). The chronic-phase fractional anisotropy (FA) and mean diffusivity (MD) values were measured at the site of the infarct and selected white matter tracts. Neurological tests in both the acute and chronic phases, and DTI lateralization were assessed with the Wilcoxon signed-rank test. The effects of thrombolytic therapy (n = 10) were assessed with the Mann-Whitney U test. The correlations between the measured parameters were analysed with Spearman's rho correlation. Bonferroni post-hoc correction was used to compensate for the familywise error rate in multiple comparisons. Several MD values in the right hemisphere correlated positively and FA values negatively with the lesion volumes. These correlations included both lesion area and healthy tissue. The results of the mini-mental state examination and the National Institutes of Health Stroke Scale also correlated with the lesion volume. A larger infarct volume is associated with more pronounced tissue modifications in the chronic stage as observed with the MD and FA alterations.

  11. Does Preinterventional Flat-Panel Computer Tomography Pooled Blood Volume Mapping Predict Final Infarct Volume After Mechanical Thrombectomy in Acute Cerebral Artery Occlusion?

    SciTech Connect

    Wagner, Marlies; Kyriakou, Yiannis; Mesnil de Rochemont, Richard du; Singer, Oliver C.; Berkefeld, Joachim

    2013-08-01

    PurposeDecreased cerebral blood volume is known to be a predictor for final infarct volume in acute cerebral artery occlusion. To evaluate the predictability of final infarct volume in patients with acute occlusion of the middle cerebral artery (MCA) or the distal internal carotid artery (ICA) and successful endovascular recanalization, pooled blood volume (PBV) was measured using flat-panel detector computed tomography (FPD CT).Materials and MethodsTwenty patients with acute unilateral occlusion of the MCA or distal ACI without demarcated infarction, as proven by CT at admission, and successful Thrombolysis in cerebral infarction score (TICI 2b or 3) endovascular thrombectomy were included. Cerebral PBV maps were acquired from each patient immediately before endovascular thrombectomy. Twenty-four hours after recanalization, each patient underwent multislice CT to visualize final infarct volume. Extent of the areas of decreased PBV was compared with the final infarct volume proven by follow-up CT the next day.ResultsIn 15 of 20 patients, areas of distinct PBV decrease corresponded to final infarct volume. In 5 patients, areas of decreased PBV overestimated final extension of ischemia probably due to inappropriate timing of data acquisition and misery perfusion.ConclusionPBV mapping using FPD CT is a promising tool to predict areas of irrecoverable brain parenchyma in acute thromboembolic stroke. Further validation is necessary before routine use for decision making for interventional thrombectomy.

  12. Quantitative microstructural deficits in chronic phase of stroke with small volume infarcts: A diffusion tensor 3-D tractographic analysis.

    PubMed

    Dubey, Prachi; Lioutas, Vasileios-Arsenios; Bhadelia, Rafeeque; Manor, Brad; Novak, Peter; Selim, Magdy; Novak, Vera

    2016-06-01

    Non-infarct zone white matter wallerian degeneration is well-documented in large volume territorial infarctions. However to what extent these abnormalities exist in small volume infarction is not known, particularly since routine T2/FLAIR MR images show minimal changes in such cases. We therefore utilized DTI based quantitative 3D tractography for quantitative assessment of white matter integrity in chronic phase of small volume anterior circulation infarcts. Eleven chronic stroke subjects with small anterior circulation large vessel infarcts (≤10cm(3) volume of primary infarct) were compared with 8 age matched controls. These infarcts had negligible to mild gliosis and encephalomalacia in the primary infarct territory without obvious wallerian degeneration on conventional MRI. Quantitative Diffusion Tensor 3-D tractography was performed for CST, genu and splenium of corpus callosum. Tract based Trace and fractional anisotropy (FA) were compared with age matched controls. On univariate analysis, Chronic stroke subjects had significant elevation in Trace measurement in genu of corpus callosum (GCC), ipsilesional and contralesional CST, (p<0.05), compared to controls. After adjusting for smoking, hypertension (HTN) and non-specific white matter hyperintensities, (WMHs), there was significant elevation in trace within the ipsilesional CST (p=0.05). Contralesional CST FA correlated significantly with walking speed, r=0.67, p=0.03. Stroke subjects with small volume infarcts demonstrate significant quantitative microstructural white matter abnormalities in chronic phase, which are otherwise subthreshold for detection on routine imaging. Ability to quantify these changes provides an important marker for assessing non-infarct zone neuroaxonal integrity in the chronic phase even in the setting of small infarction. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. The role for infarct volume as a surrogate measure of functional outcome following ischemic stroke

    PubMed Central

    Turner, Ryan C; DiPasquale, Kenneth; Logsdon, Aric F; Tan, Zhenjun; Naser, Zachary J; Huber, Jason D; Rosen, Charles L; Lucke-Wold, Brandon P

    2016-01-01

    The failed translation of proposed therapeutic agents for ischemic stroke from preclinical to clinical studies has led to increased scrutiny of preclinical studies, namely the model and outcome measures utilized. Preclinical studies routinely use infarct volume as an experimental endpoint or measure in studies employing young-adult, healthy male animals despite the fact that clinically, ischemic stroke is a disease of the elderly and improvements in functional outcome from pre- to post-intervention remains the most widely utilized assessment. The validity of infarct volume as a surrogate measure for functional outcome remains unclear in clinical studies as well as preclinical studies, particularly those utilizing a more clinically relevant aged thromboembolic model. In this work, we will address the relationship between acute and chronic functional outcome and infarct volume using a variety of functional assessments ranging from more simplistic, subjective measurements such as the modified Neurologic Severity Score (mNSS), to more complex, objective measurements such as grip strength and inclined plane.

  14. Atrial fibrillation is associated with reduced brain volume and cognitive function independent of cerebral infarcts

    PubMed Central

    Stefansdottir, Hrafnhildur; Arnar, David O.; Aspelund, Thor; Sigurdsson, Sigurdur; Jonsdottir, Maria K.; Hjaltason, Haukur; Launer, Lenore J.; Gudnason, Vilmundur

    2013-01-01

    Background and Purpose Atrial fibrillation (AF) has been associated with cognitive decline independant of stroke, suggesting additional effects of AF on the brain. We aimed to assess the association between AF and brain function and structure in a general elderly population. Methods This is a cross-sectional analysis on 4251 non-demented participants (mean age 76 ± 5 years) in the population-based AGES-Reykjavik Study. Medical record data were collected on the presence, subtype and time from first diagnosis of AF; 330 participants had AF. Brain volume measurements, adjusted for intracranial volume, and presence of cerebral infarcts were determined with MRI. Memory, speed of processing and executive function composites were calculated from a cognitive test battery. In a multivariable linear regression model, adjustments were made for demographic, cardiovascular risk factors and cerebral infarcts. Results Participants with AF had lower total brain volume compared to those without AF (p<0.001). The association was stronger with persistent/permanent than paroxysmal AF and with increased time from the first diagnosis of the disease. Of the brain tissue volumes, AF was associated with lower volume of gray and white matter (p<0.001 and p=0.008 respectively) but not of white matter hyperintesities (p=0.49). Participants with AF scored lower on tests on memory. Conclusions AF is associated with smaller brain volume and the association is stronger with increasing burden of the arrhythmia. These findings suggest that AF has a cumulative negative effect on the brain independent of cerebral infarcts. PMID:23444303

  15. Acute Infarct Extracellular Volume Mapping to Quantify Myocardial Area at Risk and Chronic Infarct Size on Cardiovascular Magnetic Resonance Imaging.

    PubMed

    Garg, Pankaj; Broadbent, David A; Swoboda, Peter P; Foley, James R J; Fent, Graham J; Musa, Tarique A; Ripley, David P; Erhayiem, Bara; Dobson, Laura E; McDiarmid, Adam K; Haaf, Philip; Kidambi, Ananth; van der Geest, Rob J; Greenwood, John P; Plein, Sven

    2017-07-01

    Late gadolinium enhancement (LGE) imaging overestimates acute infarct size. The main aim of this study was to investigate whether acute extracellular volume (ECV) maps can reliably quantify myocardial area at risk (AAR) and final infarct size (IS). Fifty patients underwent cardiovascular magnetic resonance imaging acutely (24-72 hours) and at convalescence (3 months). The cardiovascular magnetic resonance protocol included cines, T2-weighted imaging, native T1 maps, 15-minute post-contrast T1 maps, and LGE. Optimal AAR and IS ECV thresholds were derived in a validation group of 10 cases (160 segments). Eight hundred segments (16 per patient) were analyzed to quantify AAR/IS by ECV maps (ECV thresholds for AAR is 33% and IS is 46%), T2-weighted imaging, T1 maps, and acute LGE. Follow-up LGE imaging was used as the reference standard for final IS and viability assessment. The AAR derived from ECV maps (threshold of >33) demonstrated good agreement with T2-weighted imaging-derived AAR (bias, 0.18; 95% confidence interval [CI], -1.6 to 1.3) and AAR derived from native T1 maps (bias=1; 95% CI, -0.37 to 2.4). ECV demonstrated the best linear correlation to final IS at a threshold of >46% (R=0.96; 95% CI, 0.92-0.98; P<0.0001). ECV maps demonstrated better agreement with final IS than acute IS on LGE (ECV maps: bias, 1.9; 95% CI, 0.4-3.4 versus LGE imaging: bias, 10; 95% CI, 7.7-12.4). On multiple variable regression analysis, the number of nonviable segments was independently associated with IS by ECV maps (β=0.86; P<0.0001). ECV maps can reliably quantify AAR and final IS in reperfused acute myocardial infarction. Acute ECV maps were superior to acute LGE in terms of agreement with final IS. IS quantified by ECV maps are independently associated with viability at follow-up. © 2017 American Heart Association, Inc.

  16. Solulin reduces infarct volume and regulates gene-expression in transient middle cerebral artery occlusion in rats.

    PubMed

    Ryang, Yu-Mi; Dang, Jon; Kipp, Markus; Petersen, Karl-Uwe; Fahlenkamp, Astrid V; Gempt, Jens; Wesp, Dominik; Rossaint, Rolf; Beyer, Cordian; Coburn, Mark

    2011-11-14

    Thrombolysis after acute ischemic stroke has only proven to be beneficial in a subset of patients. The soluble recombinant analogue of human thrombomodulin, Solulin, was studied in an in vivo rat model of acute ischemic stroke. Male SD rats were subjected to 2 hrs of transient middle cerebral artery occlusion (tMCAO). Rats treated with Solulin intravenously shortly before reperfusion were compared to rats receiving normal saline i.v. with respect to infarct volumes, neurological deficits and mortality. Gene expression of IL-6, IL-1β, TNF-α, MMP-9, CD11B and GFAP were semiquantitatively analyzed by rtPCR of the penumbra. 24 hrs after reperfusion, rats were neurologically tested, euthanized and infarct volumes determined. Solulin significantly reduced mean total (p=0.001), cortical (p=0.002), and basal ganglia (p=0.036) infarct volumes. Hippocampal infarct volumes (p=0.191) were not significantly affected. Solulin significantly downregulated the expression of IL-1β (79%; p<0.001), TNF-α (59%; p=0.001), IL-6 (47%; p=0.04), and CD11B (49%; p=0.001) in the infarcted cortex compared to controls. Solulin reduced mean total, cortical and basal ganglia infarct volumes and regulated a subset of cytokines and proteases after tMCAO suggesting the potency of this compound for therapeutic interventions.

  17. Solulin reduces infarct volume and regulates gene-expression in transient middle cerebral artery occlusion in rats

    PubMed Central

    2011-01-01

    Background Thrombolysis after acute ischemic stroke has only proven to be beneficial in a subset of patients. The soluble recombinant analogue of human thrombomodulin, Solulin, was studied in an in vivo rat model of acute ischemic stroke. Methods Male SD rats were subjected to 2 hrs of transient middle cerebral artery occlusion (tMCAO). Rats treated with Solulin intravenously shortly before reperfusion were compared to rats receiving normal saline i.v. with respect to infarct volumes, neurological deficits and mortality. Gene expression of IL-6, IL-1β, TNF-α, MMP-9, CD11B and GFAP were semiquantitatively analyzed by rtPCR of the penumbra. Results 24 hrs after reperfusion, rats were neurologically tested, euthanized and infarct volumes determined. Solulin significantly reduced mean total (p = 0.001), cortical (p = 0.002), and basal ganglia (p = 0.036) infarct volumes. Hippocampal infarct volumes (p = 0.191) were not significantly affected. Solulin significantly downregulated the expression of IL-1β (79%; p < 0.001), TNF-α (59%; p = 0.001), IL-6 (47%; p = 0.04), and CD11B (49%; p = 0.001) in the infarcted cortex compared to controls. Conclusions Solulin reduced mean total, cortical and basal ganglia infarct volumes and regulated a subset of cytokines and proteases after tMCAO suggesting the potency of this compound for therapeutic interventions. PMID:22082476

  18. Right ventricular infarction: identification by hemodynamic measurements before and after volume loading and correlation with noninvasive techniques

    SciTech Connect

    Dell'Italia, L.J.; Starling, M.R.; Crawford, M.H.; Boros, B.L.; Chaudhuri, T.K.; O'Rourke, R.A.

    1984-11-01

    To evaluate the potential occurrence of right ventricular infarction, 53 patients with acute inferior transmural myocardial infarction were studied within 36 hours of symptoms by right heart catheterization, equilibrium radionuclide angiography and two-dimensional echocardiography. Technetium-99m pyrophosphate myocardial scintigraphy was performed 3 days after the onset of symptoms. The hemodynamic standard for right ventricular infarction was defined as both a right atrial pressure of 10 mm Hg or more and a right atrial/pulmonary artery wedge pressure ratio of 0.8 or more. Eight (15%) of the 53 patients had hemodynamic measurements at rest characteristic of right ventricular infarction, and 6 (11%) additional patients met these criteria after volume loading. Nineteen (37%) of the 51 patients who had radionuclide angiography had right ventricular dysfunction manifested by both a reduced right ventricular ejection fraction (less than 40%) and right ventricular regional wall motion abnormalities (akinesia or dyskinesia). An abnormal radionuclide angiogram was observed in 12 of 13 patients with hemodynamic measurements indicating right ventricular infarction. In 12 patients with an abnormal radionuclide angiographic study, right ventricular ejection fraction improved 6 to 12 weeks after infarction. Twenty-two (49%) of the 45 patients with adequate two-dimensional echocardiograms had a right ventricular regional wall motion abnormality. An abnormal two-dimensional echocardiogram was seen in 9 of 11 patients with hemodynamic measurements characteristic of right ventricular infarction. Technetium-99m pyrophosphate scintigraphy was positive for right ventricular infarction in 3 of 12 patients who had hemodynamic measurements indicating right ventricular infarction.

  19. Magnesium sulfate fails to reduce infarct volume following transient focal cerebral ischemia in rats.

    PubMed

    Zhu, Hong-Dong; Martin, Rosemary; Meloni, Bruno; Oltvolgyi, Csongor; Moore, Stephen; Majda, Bernadette; Knuckey, Neville

    2004-07-01

    Studies on the neuroprotective effect of magnesium treatment in animal models of focal and global cerebral ischemia have produced inconsistent results. Nevertheless, two magnesium acute stroke phase III trials (IMAGES and FAST-MAG) have either been completed or are planned. Therefore, we decided to re-evaluate the efficacy of magnesium following focal cerebral ischaemia in rats. Two experiments were carried out in two independent laboratories based in Australia. Both used the intraluminal thread method to induce focal cerebral ischemia in the rat. In the Perth study the middle cerebral artery (MCA) was occluded for 45 min and body temperature was controlled during and after ischemia. In the Canberra laboratory the MCA was occluded for 2 h and body temperature was only controlled during surgery. Three different doses (180, 360, or 720 micromol/kg) of MgSO4 in the Perth study and two different MgSO4 doses (370 or 740 micromol/kg) in the Canberra study were intravenously or intra-arterially administered immediately before ischemia. Control animals were given an equal volume of normal saline just before ischemia in both studies. Twenty-four or 72 h post-ischemia, infarct volume was determined following 2',3',5'-triphenyl-2H-tetrazolium chloride (TTC) staining. No significant differences (P > 0.05) in total, cortical and striatal infarct volumes between saline and MgSO4 treated animals were observed in either study. We conclude MgSO4 does not reduce infarct volume when administered before focal cerebral ischemia in rats.

  20. Frequency of acute asymptomatic myocardial infarction and an estimate of infarct age in cases of abrupt sudden death observed in a forensic autopsy material

    PubMed Central

    Mortensen, E S; Rognum, T O; Straume, B; Jørgensen, L

    2008-01-01

    The aim of this study is to determine the frequency of acute infarcts at autopsy in cases of unexpected abrupt deaths in persons with coronary heart disease. In addition, we want to estimate the time between onset of infarct and death based on evolving tissue changes in the infarct known to occur during the first hours. Thirty cases of unexpected, abrupt deaths were selected from a forensic autopsy material. Half of them had a preliminary diagnosis of coronary heart disease, the other half a preliminary diagnosis not involving the heart or chest area. Complete autopsies were performed. The myocardium and the coronary arteries were sampled and examined without knowledge of the gross findings or to which group the case belonged. Myocardial infarcts and acute coronary changes were found in both groups, less frequently in the non-coronary group. The age of the myocardial and coronary lesions was estimated by observing morphological characteristics changing with time, e.g. increasing polymorphonuclear leucocytes in the infarcted myocardium, and increasing amount of fibrin in thrombi. The majority of cases in the coronary group died with an extensive asymptomatic myocardial infarction, which probably had lasted 5–6 hrs or less. Acute changes in the right coronary artery and its area of supply prevailed. Acute myocardial infarcts were observed also in a minority of the non-coronary group, but myocardial infarction was not the cause of death in any of them. Abrupt coronary death is most often preceded by an extensive asymptomatic myocardial infarction within the last 5–6 hrs. PMID:18208558

  1. Estimation of extracellular fluid volume in children.

    PubMed

    Peters, A Michael

    2012-07-01

    Many equations have been developed to estimate various body fluid volumes from height and weight, but few have been developed for children. The aim of this study was to compare four height/weight formulae for estimating extracellular fluid volume (eECV) in children against measured extracellular fluid volume (mECV). The mECV was obtained from plasma Cr-51-EDTA clearance data used for routine measurement of glomerular filtration rate (GFR) in two groups of children (n=182 and 69, respectively). eECV obtained using the formulae of Abraham et al. (Clin J Am Assoc Nephrol 6:741-747, 2011) and Friis-Hansen (Pediatrics 28:169-181, 1961) were compared with mECV in both patient groups. The formulae of Bird et al. (J Nucl Med 44:1037-1043, 2003) and of Peters (Nucl Med Commun 32:375-380, 2011) were originally based on groups 1 and 2, respectively, so the eECV from them was compared with the mECV in groups 2 and 1, respectively. The eECV from the Friis-Hansen formula underestimated the mECV in larger children. Biases (mean differences between eECV and mECV) from the Bird (0.146 l) and Peters (0.029 l) formulae were not significantly different from zero, but those from the Abraham formula was higher than zero (0.694 and 0.588 l in groups 1 and 2; p<0.001). Precisions (standard deviations of the biases) of these three formulae were similar, ranging from 0.731 l (Peters) to 0.878 l (Abraham, group 2; p>0.1). The formulae of Bird, Peters and Abraham have similar precisions. The higher bias of the Abraham formula is probably due to the higher values of mECV on which their formula was based. The Friis-Hansen formula no longer has a place.

  2. Acute Ischemic Stroke: Infarct Core Estimation on CT Angiography Source Images Depends on CT Angiography Protocol

    PubMed Central

    Pulli, Benjamin; Schaefer, Pamela W.; Hakimelahi, Reza; Chaudhry, Zeshan A.; Lev, Michael H.; Hirsch, Joshua A.; González, R. Gilberto

    2012-01-01

    Purpose: To test whether the relationship between acute ischemic infarct size on concurrent computed tomographic (CT) angiography source images and diffusion-weighted (DW) magnetic resonance images is dependent on the parameters of CT angiography acquisition protocols. Materials and Methods: This retrospective study had institutional review board approval, and all records were HIPAA compliant. Data in 100 patients with anterior-circulation acute ischemic stroke and large vessel occlusion who underwent concurrent CT angiography and DW imaging within 9 hours of symptom onset were analyzed. Measured areas of hyperintensity at acute DW imaging were used as the standard of reference for infarct size. Information regarding lesion volumes and CT angiography protocol parameters was collected for each patient. For analysis, patients were divided into two groups on the basis of CT angiography protocol differences (patients in group 1 were imaged with the older, slower protocol). Intermethod agreement for infarct size was evaluated by using the Wilcoxon signed rank test, as well as by using Spearman correlation and Bland-Altman analysis. Multivariate analysis was performed to identify predictors of marked (≥20%) overestimation of infarct size on CT angiography source images. Results: In group 1 (n = 35), median hypoattenuation volumes on CT angiography source images were slightly underestimated compared with DW imaging hyperintensity volumes (33.0 vs 41.6 mL, P = .01; ratio = 0.83), with high correlation (ρ = 0.91). In group 2 (n = 65), median volume on CT angiography source images was much larger than that on DW images (94.8 vs 17.8 mL, P < .0001; ratio = 3.5), with poor correlation (ρ = 0.49). This overestimation on CT angiography source images would have inappropriately excluded from reperfusion therapy 44.4% or 90.3% of patients eligible according to DW imaging criteria on the basis of a 100-mL absolute threshold or a 20% or greater mismatch threshold, respectively

  3. Intra-Arterial Therapy and Post-Treatment Infarct Volumes: Insights From the ESCAPE Randomized Controlled Trial.

    PubMed

    Al-Ajlan, Fahad S; Goyal, Mayank; Demchuk, Andrew M; Minhas, Priyanka; Sabiq, Farahna; Assis, Zarina; Willinsky, Robert; Montanera, Walter J; Rempel, Jeremy L; Shuaib, Ashfaq; Thornton, John; Williams, David; Roy, Daniel; Poppe, Alexandre Y; Jovin, Tudor G; Sapkota, Biggya L; Baxter, Blaise W; Krings, Timo; Silver, Frank L; Frei, Donald F; Fanale, Christopher; Tampieri, Donatella; Teitelbaum, Jeanne; Lum, Cheemun; Dowlatshahi, Dar; Shankar, Jai J; Barber, Philip A; Hill, Michael D; Menon, Bijoy K

    2016-03-01

    The goal of reperfusion therapy in acute ischemic stroke is to limit brain infarction. The objective of this study was to investigate whether the beneficial effect of endovascular treatment on functional outcome could be explained by a reduction in post-treatment infarct volume. The Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times (ESCAPE) trial was a multicenter randomized open-label trial with blinded outcome evaluation. Among 315 enrolled subjects (endovascular treatment n=165; control n=150), 314 subject's infarct volumes at 24 to 48 hours on magnetic resonance imaging (n=254) or computed tomography (n=60) were measured. Post-treatment infarct volumes were compared by treatment assignment and recanalization/reperfusion status. Appropriate statistical models were used to assess relationship between baseline clinical and imaging variables, post-treatment infarct volume, and functional status at 90 days (modified Rankin Scale). Median post-treatment infarct volume in all subjects was 21 mL (interquartile range =65 mL), in the intervention arm, 15.5 mL (interquartile range =41.5 mL), and in the control arm, 33.5 mL (interquartile range =84 mL; P<0.01). Baseline National Institute of Health Stroke Scale (P<0.01), site of occlusion (P<0.01), baseline noncontrast computed tomographic scan Alberta Stroke Program Early CT score (ASPECTS) (P<0.01), and recanalization (P<0.01) were independently associated with post-treatment infarct volume, whereas age, sex, treatment type, intravenous alteplase, and time from onset to randomization were not (P>0.05). Post-treatment infarct volume (P<0.01) and delta National Institute of Health Stroke Scale (P<0.01) were independently associated with 90-day modified Rankin Scale, whereas laterality (left versus right) was not. These results support the primary results of the ESCAPE trial and show that the biological underpinning of the success of

  4. Remote Zone Extracellular Volume and Left Ventricular Remodeling in Survivors of ST-Elevation Myocardial Infarction.

    PubMed

    Carberry, Jaclyn; Carrick, David; Haig, Caroline; Rauhalammi, Samuli M; Ahmed, Nadeem; Mordi, Ify; McEntegart, Margaret; Petrie, Mark C; Eteiba, Hany; Hood, Stuart; Watkins, Stuart; Lindsay, Mitchell; Davie, Andrew; Mahrous, Ahmed; Ford, Ian; Sattar, Naveed; Welsh, Paul; Radjenovic, Aleksandra; Oldroyd, Keith G; Berry, Colin

    2016-08-01

    The natural history and pathophysiological significance of tissue remodeling in the myocardial remote zone after acute ST-elevation myocardial infarction (STEMI) is incompletely understood. Extracellular volume (ECV) in myocardial regions of interest can now be measured with cardiac magnetic resonance imaging. Patients who sustained an acute STEMI were enrolled in a cohort study (BHF MR-MI [British Heart Foundation Magnetic Resonance Imaging in Acute ST-Segment Elevation Myocardial Infarction study]). Cardiac magnetic resonance was performed at 1.5 Tesla at 2 days and 6 months post STEMI. T1 modified Look-Locker inversion recovery mapping was performed before and 15 minutes after contrast (0.15 mmol/kg gadoterate meglumine) in 140 patients at 2 days post STEMI (mean age: 59 years, 76% male) and in 131 patients at 6 months post STEMI. Remote zone ECV was lower than infarct zone ECV (25.6±2.8% versus 51.4±8.9%; P<0.001). In multivariable regression, left ventricular ejection fraction was inversely associated with remote zone ECV (P<0.001), and diabetes mellitus was positively associated with remote zone ECV (P=0.010). No ST-segment resolution (P=0.034) and extent of ischemic area at risk (P<0.001) were multivariable associates of the change in remote zone ECV at 6 months (ΔECV). ΔECV was a multivariable associate of the change in left ventricular end-diastolic volume at 6 months (regression coefficient [95% confidence interval]: 1.43 (0.10-2.76); P=0.036). ΔECV is implicated in the pathophysiology of left ventricular remodeling post STEMI, but because the effect size is small, ΔECV has limited use as a clinical biomarker of remodeling. URL: https://www.clinicaltrials.gov. Unique identifier: NCT02072850. © 2016 The Authors.

  5. Remote Zone Extracellular Volume and Left Ventricular Remodeling in Survivors of ST-Elevation Myocardial Infarction

    PubMed Central

    Carberry, Jaclyn; Carrick, David; Haig, Caroline; Rauhalammi, Samuli M.; Ahmed, Nadeem; Mordi, Ify; McEntegart, Margaret; Petrie, Mark C.; Eteiba, Hany; Hood, Stuart; Watkins, Stuart; Lindsay, Mitchell; Davie, Andrew; Mahrous, Ahmed; Ford, Ian; Sattar, Naveed; Welsh, Paul; Radjenovic, Aleksandra; Oldroyd, Keith G.

    2016-01-01

    The natural history and pathophysiological significance of tissue remodeling in the myocardial remote zone after acute ST-elevation myocardial infarction (STEMI) is incompletely understood. Extracellular volume (ECV) in myocardial regions of interest can now be measured with cardiac magnetic resonance imaging. Patients who sustained an acute STEMI were enrolled in a cohort study (BHF MR-MI [British Heart Foundation Magnetic Resonance Imaging in Acute ST-Segment Elevation Myocardial Infarction study]). Cardiac magnetic resonance was performed at 1.5 Tesla at 2 days and 6 months post STEMI. T1 modified Look-Locker inversion recovery mapping was performed before and 15 minutes after contrast (0.15 mmol/kg gadoterate meglumine) in 140 patients at 2 days post STEMI (mean age: 59 years, 76% male) and in 131 patients at 6 months post STEMI. Remote zone ECV was lower than infarct zone ECV (25.6±2.8% versus 51.4±8.9%; P<0.001). In multivariable regression, left ventricular ejection fraction was inversely associated with remote zone ECV (P<0.001), and diabetes mellitus was positively associated with remote zone ECV (P=0.010). No ST-segment resolution (P=0.034) and extent of ischemic area at risk (P<0.001) were multivariable associates of the change in remote zone ECV at 6 months (ΔECV). ΔECV was a multivariable associate of the change in left ventricular end-diastolic volume at 6 months (regression coefficient [95% confidence interval]: 1.43 (0.10–2.76); P=0.036). ΔECV is implicated in the pathophysiology of left ventricular remodeling post STEMI, but because the effect size is small, ΔECV has limited use as a clinical biomarker of remodeling. Clinical Trial Registration— URL: https://www.clinicaltrials.gov. Unique identifier: NCT02072850. PMID:27354423

  6. The number of circulating CD14+ cells is related to infarct size and postinfarct volumes in ST segment elevation myocardial infarction but not non-ST segment elevation myocardial infarction

    PubMed Central

    Montange, Damien; Davani, Siamak; Deschaseaux, Frédéric; Séronde, Marie France; Chopard, Romain; Schiele, François; Jehl, Jérome; Bassand, Jean Pierre; Kantelip, Jean-Pierre; Meneveau, Nicolas

    2012-01-01

    OBJECTIVE: To determine the relationship between the number of CD14+ cells, myocardial infarct (MI) size and left ventricular (LV) volumes in ST segment elevation MI (STEMI) and non-ST segment elevation MI (NSTEMI) patients. METHODS: A total of 62 patients with STEMI (n=34) or NSTEMI (n=28) were enrolled. The number of CD14+ cells was assessed at admission. Infarct size, left ventricular ejection fraction (LVEF) and LV volumes were measured using magnetic resonance imaging five days after MI and six months after MI. Results: In STEMI patients, the number of CD14+ cells was positively and significantly correlated with infarct size at day 5 (r=0.40; P=0.016) and after six months (r=0.34; P=0.047), negatively correlated with LVEF at day 5 (r=−0.50; P=0.002) and after six months (r=−0.46; P=0.005) and positively correlated with end-diastolic (r=0.38; P=0.02) and end-systolic (r=0.49; P=0.002) volumes after six months. In NSTEMI patients, no significant correlation was found between the number of CD14+ cells and infarct size, LVEF or LV volumes at day 5 or after six months. CONCLUSIONS: The number of CD14+ cells at admission was associated with infarct size and LV remodelling in STEMI patients with large infarct size, whereas in NSTEMI patients, no relationship was observed between numbers of CD14+ cells and LV remodelling. PMID:23620701

  7. Photographic Volume Estimation of CPAS Main Parachutes

    NASA Technical Reports Server (NTRS)

    Ray, Eric S.

    2017-01-01

    Capsule Parachute Assembly System (CPAS) flight tests regularly stage a helicopter to observe inflation of 116 ft D o ringsail Main parachutes. These side views can be used to generate 3-D models of inflating canopies to estimate enclosed volume. Assuming a surface of revolution is inadequate because reefed canopies in a cluster are elongated due to mutual aerodynamic interference. A method was developed to combine the side views with upward looking HD video to account for non-circular cross sections. Approximating the cross sections as elliptical greatly improves accuracy. But since that correction requires manually tracing projected outlines, the actual irregular shapes can be used to generate high fidelity models. Compensation is also made for apparent tilt angle. Validation was accomplished by comparing perimeter and projected area with known line lengths and/or high quality photogrammetry.

  8. Natural allelic variation of the IL-21 receptor modulates ischemic stroke infarct volume.

    PubMed

    Lee, Han Kyu; Keum, Sehoon; Sheng, Huaxin; Warner, David S; Lo, Donald C; Marchuk, Douglas A

    2016-08-01

    Risk for ischemic stroke has a strong genetic basis, but heritable factors also contribute to the extent of damage after a stroke has occurred. We previously identified a locus on distal mouse chromosome 7 that contributes over 50% of the variation in postischemic cerebral infarct volume observed between inbred strains. Here, we used ancestral haplotype analysis to fine-map this locus to 12 candidate genes. The gene encoding the IL-21 receptor (Il21r) showed a marked difference in strain-specific transcription levels and coding variants in neonatal and adult cortical tissue. Collateral vessel connections were moderately reduced in Il21r-deficient mice, and cerebral infarct volume increased 2.3-fold, suggesting that Il21r modulates both collateral vessel anatomy and innate neuroprotection. In brain slice explants, oxygen deprivation (OD) activated apoptotic pathways and increased neuronal cell death in IL-21 receptor-deficient (IL-21R-deficient) mice compared with control animals. We determined that the neuroprotective effects of IL-21R arose from signaling through JAK/STAT pathways and upregulation of caspase 3. Thus, natural genetic variation in murine Il21r influences neuronal cell viability after ischemia by modulating receptor function and downstream signal transduction. The identification of neuroprotective genes based on naturally occurring allelic variations has the potential to inform the development of drug targets for ischemic stroke treatment.

  9. Natural allelic variation of the IL-21 receptor modulates ischemic stroke infarct volume

    PubMed Central

    Lee, Han Kyu; Keum, Sehoon; Sheng, Huaxin; Warner, David S.; Lo, Donald C.

    2016-01-01

    Risk for ischemic stroke has a strong genetic basis, but heritable factors also contribute to the extent of damage after a stroke has occurred. We previously identified a locus on distal mouse chromosome 7 that contributes over 50% of the variation in postischemic cerebral infarct volume observed between inbred strains. Here, we used ancestral haplotype analysis to fine-map this locus to 12 candidate genes. The gene encoding the IL-21 receptor (Il21r) showed a marked difference in strain-specific transcription levels and coding variants in neonatal and adult cortical tissue. Collateral vessel connections were moderately reduced in Il21r-deficient mice, and cerebral infarct volume increased 2.3-fold, suggesting that Il21r modulates both collateral vessel anatomy and innate neuroprotection. In brain slice explants, oxygen deprivation (OD) activated apoptotic pathways and increased neuronal cell death in IL-21 receptor–deficient (IL-21R–deficient) mice compared with control animals. We determined that the neuroprotective effects of IL-21R arose from signaling through JAK/STAT pathways and upregulation of caspase 3. Thus, natural genetic variation in murine Il21r influences neuronal cell viability after ischemia by modulating receptor function and downstream signal transduction. The identification of neuroprotective genes based on naturally occurring allelic variations has the potential to inform the development of drug targets for ischemic stroke treatment. PMID:27400126

  10. Reduced brain edema and infarct volume in aquaporin-4 deficient mice after transient focal cerebral ischemia.

    PubMed

    Yao, Xiaoming; Derugin, Nikita; Manley, Geoffrey T; Verkman, A S

    2015-01-01

    Aquaporin-4 (AQP4) is a water channel expressed in astrocyte end-feet lining the blood-brain barrier. AQP4 deletion in mice is associated with improved outcomes in global cerebral ischemia produced by transient carotid artery occlusion, and focal cerebral ischemia produced by permanent middle cerebral artery occlusion (MCAO). Here, we investigated the consequences of 1-h transient MCAO produced by intraluminal suture blockade followed by 23 h of reperfusion. In nine AQP4(+/+) and nine AQP4(-/-) mice, infarct volume was significantly reduced by an average of 39 ± 4% at 24h in AQP4(-/-) mice, cerebral hemispheric edema was reduced by 23 ± 3%, and Evans Blue extravasation was reduced by 31 ± 2% (mean ± SEM). Diffusion-weighted magnetic resonance imaging showed greatest reduction in apparent diffusion coefficient around the occlusion site after reperfusion, with remarkably lesser reduction in AQP4(-/-) mice. The reduced infarct volume in AQP4(-/-) mice following transient MCAO supports the potential utility of therapeutic AQP4 inhibition in stroke.

  11. Early magnetic resonance imaging prediction of arterial recanalization and late infarct volume in acute carotid artery stroke.

    PubMed

    Hermier, Marc; Nighoghossian, Norbert; Adeleine, Patrice; Berthezène, Yves; Derex, Laurent; Yilmaz, Hasan; Dugor, Jean-François; Dardel, Pascal; Cotton, François; Philippeau, Frédéric; Trouillas, Paul; Froment, Jean-Claude

    2003-02-01

    In patients with acute ischemic stroke, early recanalization may save tissue at risk for ischemic infarction, thus resulting in smaller infarcts and better clinical outcome. The hypothesis that clinical and diffusion- and perfusion-weighted imaging (DWI, PWI) parameters may have a predictive value for early recanalization and final infarct size was assessed. Twenty-nine patients were prospectively enrolled and underwent sequential magnetic resonance imaging (1) within 6 hours from hemispheric stroke onset, before thrombolytic therapy; (2) at day 1; and (3) at day 60. Late infarct volume was assessed by T2 -weighted imaging. At each time, clinical status was assessed by the National Institutes of Health Stroke Scale (NIHSS). Twenty-eight patients had arterial occlusion at day 0 magnetic resonance angiography (MRA). They were classified into two groups according to day 1 MRA: recanalization (n = 18) versus persistent occlusion (n = 10). Any significant differences between these groups were assessed regarding (1) PWI and DWI abnormality volumes, (2) relative and absolute time-to-peak (TTP) and apparent diffusion coefficient within the lesion on DWI; and (3) day 60 lesion volume on T2 -weighted imaging. Univariate and multivariate logistic regression analysis showed that the most powerful predictive factors for recanalization were lower baseline NIHSS score and lower baseline absolute TTP within the lesion on DWI. The best predictors of late infarct size were day 0 lesion volume on DWI and day 1 recanalization. Early PWI and DWI studies and day 1 MRA provide relevant predictive information on stroke outcome.

  12. Acute myocardial infarction: estimation of at-risk and salvaged myocardium at myocardial perfusion SPECT 1 month after infarction.

    PubMed

    Romero-Farina, Guillermo; Aguadé-Bruix, Santiago; Candell-Riera, Jaume; Pizzi, M Nazarena; Pineda, Victor; Figueras, Jaume; Cuberas, Gemma; de León, Gustavo; Castell-Conesa, Joan; García-Dorado, David

    2013-11-01

    To estimate at-risk and salvaged myocardium by using gated single photon emission computed tomography (SPECT) myocardial perfusion imaging after acute myocardial infarction (AMI). The study was approved by the hospital's Ethical Committee on Clinical Trials (trial register number, PR(HG)36/2000), and all patients gave informed consent. Forty patients (mean age, 61.78 years; eight women) with a first AMI underwent two gated SPECT examinations--one before percutaneous coronary intervention (PCI) and one 4-5 weeks after PCI. Myocardium at risk was estimated by assessing the perfusion defect at the first gated SPECT examination, and salvaged myocardium was estimated by assessing the risk area minus necrosis at the second examination. Myocardium at risk was estimated by determining the discordance between the areas of left ventricular (LV) wall motion and perfusion at the second examination. Concordance between tests was analyzed by means of linear regression analysis, the Pearson correlation, the intraclass correlation coefficient, and Bland-Altman analysis. An improvement in perfusion, wall motion, wall thickening, and LV ejection fraction (P < .001) was observed at 1 month. At 1 month, the area with abnormal wall motion was greater than the area of altered perfusion (35.47 vs 23.1 cm(2); P = .007). The extent of myocardium at risk estimated from this discordance correlated well with myocardium at risk measured at the first gated SPECT examination and with salvaged myocardium between both studies (Pearson correlation: 0.78 and 0.6, respectively). Concordance for correct classification of patients with salvaged myocardium of 50% or greater was 83% (κ = 0.65). Myocardial perfusion gated SPECT performed 1 month after early PCI in a first AMI provides potentially useful information on at-risk and salvaged myocardium. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13122324/-/DC1. RSNA, 2013

  13. Intensive Care Units With Low Versus High Volume of Myocardial Infarction: Clinical Outcomes, Resource Utilization, and Quality Metrics

    PubMed Central

    Stolker, Joshua M; Badawi, Omar; Spertus, John A; Nasir, Ammar; Kennedy, Kevin F; Harris, Ilene H; Franey, Christine S; Hsu, Van Doren; Ripple, Gary R; Howell, Gregory H; Lem, Vincent M; Chan, Paul S

    2015-01-01

    Background The volume-outcome relationship associated with intensive care unit (ICU) experience with managing acute myocardial infarction (AMI) remains inadequately understood. Methods and Results Within a multicenter clinical ICU database, we identified patients with a primary ICU admission diagnosis of AMI between 2008 and 2010 to evaluate whether annual AMI volume of an individual ICU is associated with mortality, length-of-stay, or quality indicators. Patients were categorized into those treated in ICUs with low-annual-AMI volume (≤50th percentile, <2 AMI patients/month, n=569 patients) versus high-annual-AMI volume (≥90th percentile, ≥8 AMI patients/month, n=17 553 patients). Poisson regression and generalized estimating equation with negative binomial regression were used to calculate the relative risk (95% CI) for mortality and length-of-stay, respectively, associated with admission to a low-AMI-volume ICU. When compared with high-AMI-volume, patients admitted to low-AMI-volume ICUs had substantially more medical comorbidities, higher in-hospital mortality (11% versus 4%, P<0.001), longer hospitalizations (6.9±7.0 versus 5.0±5.0 days, P<0.001), and fewer evidence-based therapies for AMI (reperfusion therapy, antiplatelets, β-blockers, and statins). However, after adjustment for baseline patient characteristics, low-AMI-volume ICU was no longer an independent predictor of in-hospital mortality (relative risk 1.17 [0.87 to 1.56]) or hospital length-of-stay (relative risk 1.01 [0.94 to 1.08]). Similar findings were noted in secondary analyses of ICU mortality and ICU length-of-stay. Conclusions Admission to an ICU with lower annual AMI volume is associated with higher in-hospital mortality, longer hospitalization, and lower use of evidence-based therapies for AMI. However, the relationship between low-AMI-volume and outcomes is no longer present after accounting for the higher-risk medical comorbidities and clinical characteristics of patients

  14. Using GIS to Estimate Lake Volume from Limited Data

    EPA Science Inventory

    Estimates of lake volume are necessary for estimating residence time or modeling pollutants. Modern GIS methods for calculating lake volume improve upon more dated technologies (e.g. planimeters) and do not require potentially inaccurate assumptions (e.g. volume of a frustum of ...

  15. Using GIS to Estimate Lake Volume from Limited Data

    EPA Science Inventory

    Estimates of lake volume are necessary for estimating residence time or modeling pollutants. Modern GIS methods for calculating lake volume improve upon more dated technologies (e.g. planimeters) and do not require potentially inaccurate assumptions (e.g. volume of a frustum of ...

  16. Estimation of feline renal volume using computed tomography and ultrasound.

    PubMed

    Tyson, Reid; Logsdon, Stacy A; Werre, Stephen R; Daniel, Gregory B

    2013-01-01

    Renal volume estimation is an important parameter for clinical evaluation of kidneys and research applications. A time efficient, repeatable, and accurate method for volume estimation is required. The purpose of this study was to describe the accuracy of ultrasound and computed tomography (CT) for estimating feline renal volume. Standardized ultrasound and CT scans were acquired for kidneys of 12 cadaver cats, in situ. Ultrasound and CT multiplanar reconstructions were used to record renal length measurements that were then used to calculate volume using the prolate ellipsoid formula for volume estimation. In addition, CT studies were reconstructed at 1 mm, 5 mm, and 1 cm, and transferred to a workstation where the renal volume was calculated using the voxel count method (hand drawn regions of interest). The reference standard kidney volume was then determined ex vivo using water displacement with the Archimedes' principle. Ultrasound measurement of renal length accounted for approximately 87% of the variability in renal volume for the study population. The prolate ellipsoid formula exhibited proportional bias and underestimated renal volume by a median of 18.9%. Computed tomography volume estimates using the voxel count method with hand-traced regions of interest provided the most accurate results, with increasing accuracy for smaller voxel sizes in grossly normal kidneys (-10.1 to 0.6%). Findings from this study supported the use of CT and the voxel count method for estimating feline renal volume in future clinical and research studies.

  17. Cardiac computed tomography-derived epicardial fat volume and attenuation independently distinguish patients with and without myocardial infarction

    PubMed Central

    Balcer, Bastian; Dykun, Iryna; Forsting, Michael; Schlosser, Thomas; Heusch, Gerd; Rassaf, Tienush

    2017-01-01

    Background and objective Epicardial adipose tissue (EAT) volume is associated with coronary plaque burden and adverse events. We aimed to determine, whether CT-derived EAT attenuation in addition to EAT volume distinguishes patients with and without myocardial infarction. Methods and results In 94 patients with confirmed or suspected coronary artery disease (aged 66.9±14.7years, 61%male) undergoing cardiac CT imaging as part of clinical workup, EAT volume was retrospectively quantified from non-contrast cardiac CT by delineation of the pericardium in axial images. Mean attenuation of all pixels from EAT volume was calculated. Patients with type-I myocardial infarction (n = 28) had higher EAT volume (132.9 ± 111.9ml vs. 109.7 ± 94.6ml, p = 0.07) and CT-attenuation (-86.8 ± 5.8HU vs. -89.0 ± 3.7HU, p = 0.03) than patients without type-I myocardial infarction, while EAT volume and attenuation were only modestly inversely correlated (r = -0.24, p = 0.02). EAT volume increased per standard deviation of age (18.2 [6.2–30.2] ml, p = 0.003), BMI (29.3 [18.4–40.2] ml, p<0.0001), and with presence of diabetes (44.5 [16.7–72.3] ml, p = 0.0002), while attenuation was higher in patients with lipid-lowering therapy (2.34 [0.08–4.61] HU, p = 0.04). In a model containing volume and attenuation, both measures of EAT were independently associated with the occurrence of type-I myocardial infarction (OR [95% CI]: 1.79 [1.10–2.94], p = 0.02 for volume, 2.04 [1.18–3.53], p = 0.01 for attenuation). Effect sizes remained stable for EAT attenuation after adjustment for risk factors (1.44 [0.77–2.68], p = 0.26 for volume; 1.93 [1.11–3.39], p = 0.02 for attenuation). Conclusion CT-derived EAT attenuation, in addition to volume, distinguishes patients with vs. without myocardial infarction and is increased in patients with lipid-lowering therapy. Our results suggest that assessment of EAT attenuation could render complementary information to EAT volume regarding coronary

  18. Relationship between plasma metalloproteinase-9 levels and volume and severity of infarct in patients with acute ischemic stroke.

    PubMed

    Demir, Recep; Ulvi, Hızır; Özel, Lütfi; Özdemir, Gökhan; Güzelcik, Metin; Aygül, Recep

    2012-12-01

    Matrix metalloproteinases (MMP) constitute an endopeptidase family involved in various physiological and pathological processes. It was demonstrated that plasma MMP-9 level was increased in patients with acute ischemic stroke. In this study, it was investigated whether there was a relationship between the levels of plasma MMP-9 and the severity of stroke and infarct volume in patients with acute ischemic stroke. A total of 32 patients with acute ischemic stroke, (16 males and 16 females) and 30 healthy controls were included in the study. Plasma MMP-9 levels were measured using ELISA method. Computed tomography was performed at 48th hour and infarct volume was calculated using the Cavalieri method. The National Institute of Health Stroke Scale (NIHSS) was checked at baseline, 12, 24, and 48th hour. Plasma MMP-9 levels of the patient group at baseline, 12, 24, and 48th hour were found significantly higher compared to the control group (p < 0.05). An important correlation between MMP-9 levels and the infarct volume was observed at baseline, 12, 24, and 48th hour (p < 0.001). Furthermore, a positive correlation was recorded between plasma MMP-9 levels and NIHSS scores at baseline, 12, 24, and 48th hour (p < 0.001). Plasma MMP-9 levels of those of suffering medium and heavy damages were found significantly higher when compared to those of having slight damage (p < 0.05). A significant relationship was also observed between infarct volumes and neurological deficits (p < 0.05). Plasma MMP-9 levels of the patients at 48th hour were found to be significantly lower in recovered patients compared to those who did not improved or worsened (p < 0.05). A positive correlation was recorded between the infarct volume and infarct progression (p < 0.05). In conclusion, this study showed that plasma MMP-9 level substantially increased during the acute period of ischemic cerebrovascular disease and correlated with the severity of the disease and infarct volume. The

  19. Estimating Lake Volume from Limited Data: A Simple GIS Approach

    EPA Science Inventory

    Lake volume provides key information for estimating residence time or modeling pollutants. Methods for calculating lake volume have relied on dated technologies (e.g. planimeters) or used potentially inaccurate assumptions (e.g. volume of a frustum of a cone). Modern GIS provid...

  20. Estimating Lake Volume from Limited Data: A Simple GIS Approach

    EPA Science Inventory

    Lake volume provides key information for estimating residence time or modeling pollutants. Methods for calculating lake volume have relied on dated technologies (e.g. planimeters) or used potentially inaccurate assumptions (e.g. volume of a frustum of a cone). Modern GIS provid...

  1. Intra-thoracic fat volume is associated with myocardial infarction in patients with metabolic syndrome.

    PubMed

    Jolly, Umjeet S; Soliman, Abraam; McKenzie, Charles; Peters, Terry; Stirrat, John; Nevis, Immaculate; Brymer, Matthew; Joy, Tisha; Drangova, Maria; White, James A

    2013-09-10

    Visceral adiposity is increased in those with Metabolic Syndrome (MetS) and atherosclerotic disease burden. In this study we evaluate for associations between intra-thoracic fat volume (ITFV) and myocardial infarction (MI) in patients with MetS. Ninety-four patients with MetS, MI or both were identified from a cardiovascular CMR clinical registry. MetS was defined in accordance to published guidelines; where-as MI was defined as the presence of subendocardial-based injury on late gadolinium enhancement imaging in a coronary vascular distribution. A healthy control group was also obtained from the same registry. Patients were selected into the following groups: MetS+/MI- (N = 32), MetS-/MI + (N = 30), MetS+/MI + (N = 32), MetS-/MI- (N = 16). ITFV quantification was performed using signal threshold analysis of sequential sagittal CMR datasets (HASTE) and indexed to body mass index. The mean age of the population was 59.8 ± 12.5 years. MetS+ patients (N=64) demonstrated a significantly higher indexed ITFV compared to MetS- patients (p = 0.05). Patients in respective MetS-/MI-, MetS+/MI-, MetS-/MI+, and MetS+/MI + study groups demonstrated a progressive elevation in the indexed ITFV (22.3 ± 10.6, 28.6 ± 12.6, 30.6 ± 12.3, and 35.2 ± 1.4 ml/kg/m(2), (p = 0.002)). Among MetS+ patients those with MI showed a significantly higher indexed ITFV compared to those without MI (p = 0.02). ITFV is elevated in patients with MetS and incrementally elevated among those with evidence of prior ischemic myocardial injury. Accordingly, the quantification of ITFV may be a valuable marker of myocardial infarction risk among patients with MetS and warrants further investigation.

  2. Therapeutic effect of nerve growth factor on cerebral infarction in dogs using the hemisphere anomalous volume ratio of diffusion-weighted magnetic resonance imaging.

    PubMed

    Wang, Yong; Zhang, Hui; Wang, Zhe; Geng, Zuojun; Liu, Huaijun; Yang, Haiqing; Song, Peng; Liu, Qing

    2012-08-25

    A model of focal cerebral ischemic infarction was established in dogs through middle cerebral artery occlusion of the right side. Thirty minutes after occlusion, models were injected with nerve growth factor adjacent to the infarct locus. The therapeutic effect of nerve growth factor against cerebral infarction was assessed using the hemisphere anomalous volume ratio, a quantitative index of diffusion-weighted MRI. At 6 hours, 24 hours, 7 days and 3 months after modeling, the hemisphere anomalous volume ratio was significantly reduced after treatment with nerve growth factor. Hematoxylin-eosin staining, immunohistochemistry, electron microscopy and neurological function scores showed that infarct defects were slightly reduced and neurological function significantly improved after nerve growth factor treatment. This result was consistent with diffusion-weighted MRI measurements. Experimental findings indicate that nerve growth factor can protect against cerebral infarction, and that the hemisphere anomalous volume ratio of diffusion-weighted MRI can be used to evaluate the therapeutic effect.

  3. Therapeutic effect of nerve growth factor on cerebral infarction in dogs using the hemisphere anomalous volume ratio of diffusion-weighted magnetic resonance imaging★

    PubMed Central

    Wang, Yong; Zhang, Hui; Wang, Zhe; Geng, Zuojun; Liu, Huaijun; Yang, Haiqing; Song, Peng; Liu, Qing

    2012-01-01

    A model of focal cerebral ischemic infarction was established in dogs through middle cerebral artery occlusion of the right side. Thirty minutes after occlusion, models were injected with nerve growth factor adjacent to the infarct locus. The therapeutic effect of nerve growth factor against cerebral infarction was assessed using the hemisphere anomalous volume ratio, a quantitative index of diffusion-weighted MRI. At 6 hours, 24 hours, 7 days and 3 months after modeling, the hemisphere anomalous volume ratio was significantly reduced after treatment with nerve growth factor. Hematoxylin-eosin staining, immunohistochemistry, electron microscopy and neurological function scores showed that infarct defects were slightly reduced and neurological function significantly improved after nerve growth factor treatment. This result was consistent with diffusion-weighted MRI measurements. Experimental findings indicate that nerve growth factor can protect against cerebral infarction, and that the hemisphere anomalous volume ratio of diffusion-weighted MRI can be used to evaluate the therapeutic effect. PMID:25624813

  4. Using Photogrammetry to Estimate Tank Waste Volumes from Video

    SciTech Connect

    Field, Jim G.

    2013-03-27

    Washington River Protection Solutions (WRPS) contracted with HiLine Engineering & Fabrication, Inc. to assess the accuracy of photogrammetry tools as compared to video Camera/CAD Modeling System (CCMS) estimates. This test report documents the results of using photogrammetry to estimate the volume of waste in tank 241-C-I04 from post-retrieval videos and results using photogrammetry to estimate the volume of waste piles in the CCMS test video.

  5. Anesthesia-Induced Hypothermia Attenuates Early-Phase Blood-Brain Barrier Disruption but Not Infarct Volume following Cerebral Ischemia.

    PubMed

    Liu, Yu-Cheng; Lee, Yu-Da; Wang, Hwai-Lee; Liao, Kate Hsiurong; Chen, Kuen-Bao; Poon, Kin-Shing; Pan, Yu-Ling; Lai, Ted Weita

    2017-01-01

    Blood-brain barrier (BBB) disruption is thought to facilitate the development of cerebral infarction after a stroke. In a typical stroke model (such as the one used in this study), the early phase of BBB disruption reaches a peak 6 h post-ischemia and largely recovers after 8-24 h, whereas the late phase of BBB disruption begins 48-58 h post-ischemia. Because cerebral infarct develops within 24 h after the onset of ischemia, and several therapeutic agents have been shown to reduce the infarct volume when administered at 6 h post-ischemia, we hypothesized that attenuating BBB disruption at its peak (6 h post-ischemia) can also decrease the infarct volume measured at 24 h. We used a mouse stroke model obtained by combining 120 min of distal middle cerebral arterial occlusion (dMCAo) with ipsilateral common carotid arterial occlusion (CCAo). This model produced the most reliable BBB disruption and cerebral infarction compared to other models characterized by a shorter duration of ischemia or obtained with dMCAO or CCAo alone. The BBB permeability was measured by quantifying Evans blue dye (EBD) extravasation, as this tracer has been shown to be more sensitive for the detection of early-phase BBB disruption compared to other intravascular tracers that are more appropriate for detecting late-phase BBB disruption. We showed that a 1 h-long treatment with isoflurane-anesthesia induced marked hypothermia and attenuated the peak of BBB disruption when administered 6 h after the onset of dMCAo/CCAo-induced ischemia. We also demonstrated that the inhibitory effect of isoflurane was hypothermia-dependent because the same treatment had no effect on ischemic BBB disruption when the mouse body temperature was maintained at 37°C. Importantly, inhibiting the peak of BBB disruption by hypothermia had no effect on the volume of brain infarct 24 h post-ischemia. In conclusion, inhibiting the peak of BBB disruption is not an effective neuroprotective strategy, especially in comparison

  6. Anesthesia-Induced Hypothermia Attenuates Early-Phase Blood-Brain Barrier Disruption but Not Infarct Volume following Cerebral Ischemia

    PubMed Central

    Liu, Yu-Cheng; Lee, Yu-Da; Wang, Hwai-Lee; Liao, Kate Hsiurong; Chen, Kuen-Bao; Poon, Kin-Shing; Pan, Yu-Ling

    2017-01-01

    Blood-brain barrier (BBB) disruption is thought to facilitate the development of cerebral infarction after a stroke. In a typical stroke model (such as the one used in this study), the early phase of BBB disruption reaches a peak 6 h post-ischemia and largely recovers after 8–24 h, whereas the late phase of BBB disruption begins 48–58 h post-ischemia. Because cerebral infarct develops within 24 h after the onset of ischemia, and several therapeutic agents have been shown to reduce the infarct volume when administered at 6 h post-ischemia, we hypothesized that attenuating BBB disruption at its peak (6 h post-ischemia) can also decrease the infarct volume measured at 24 h. We used a mouse stroke model obtained by combining 120 min of distal middle cerebral arterial occlusion (dMCAo) with ipsilateral common carotid arterial occlusion (CCAo). This model produced the most reliable BBB disruption and cerebral infarction compared to other models characterized by a shorter duration of ischemia or obtained with dMCAO or CCAo alone. The BBB permeability was measured by quantifying Evans blue dye (EBD) extravasation, as this tracer has been shown to be more sensitive for the detection of early-phase BBB disruption compared to other intravascular tracers that are more appropriate for detecting late-phase BBB disruption. We showed that a 1 h-long treatment with isoflurane-anesthesia induced marked hypothermia and attenuated the peak of BBB disruption when administered 6 h after the onset of dMCAo/CCAo-induced ischemia. We also demonstrated that the inhibitory effect of isoflurane was hypothermia-dependent because the same treatment had no effect on ischemic BBB disruption when the mouse body temperature was maintained at 37°C. Importantly, inhibiting the peak of BBB disruption by hypothermia had no effect on the volume of brain infarct 24 h post-ischemia. In conclusion, inhibiting the peak of BBB disruption is not an effective neuroprotective strategy, especially in

  7. Myocardial strain estimation from CT: towards computer-aided diagnosis on infarction identification

    NASA Astrophysics Data System (ADS)

    Wong, Ken C. L.; Tee, Michael; Chen, Marcus; Bluemke, David A.; Summers, Ronald M.; Yao, Jianhua

    2015-03-01

    Regional myocardial strains have the potential for early quantification and detection of cardiac dysfunctions. Although image modalities such as tagged and strain-encoded MRI can provide motion information of the myocardium, they are uncommon in clinical routine. In contrary, cardiac CT images are usually available, but they only provide motion information at salient features such as the cardiac boundaries. To estimate myocardial strains from a CT image sequence, we adopted a cardiac biomechanical model with hyperelastic material properties to relate the motion on the cardiac boundaries to the myocardial deformation. The frame-to-frame displacements of the cardiac boundaries are obtained using B-spline deformable image registration based on mutual information, which are enforced as boundary conditions to the biomechanical model. The system equation is solved by the finite element method to provide the dense displacement field of the myocardium, and the regional values of the three principal strains and the six strains in cylindrical coordinates are computed in terms of the American Heart Association nomenclature. To study the potential of the estimated regional strains on identifying myocardial infarction, experiments were performed on cardiac CT image sequences of ten canines with artificially induced myocardial infarctions. The leave-one-subject-out cross validations show that, by using the optimal strain magnitude thresholds computed from ROC curves, the radial strain and the first principal strain have the best performance.

  8. Casualty Estimates for Contingencies. Volume 2. Appendices.

    DTIC Science & Technology

    1985-11-15

    Virginia 220i1 II . CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE USACAA 15 November 1985 8120 Woodmont Ave. 13. NUMBER OF PAGES Bethesda...Maryland 20814 14. MONITORING AGENCY NAME & ADDRESS( II different from Conlrollin Office) IS. SECURITY CLASS, (of this report) UNCLASSIFIED IS...day) for contingency engagements in general and, specifically, with reference to a variety of situational or circumstantial variables. Volume II

  9. Prediction of Infarct Lesion Volumes by Processing Magnetic Resonance Apparent Diffusion Coefficient Maps in Patients with Acute Ischemic Stroke.

    PubMed

    Qian, Qi; Huang, Hai-Tao; Xu, Li; Jin, Ping; Lin, Min

    2016-12-01

    We aimed to investigate the diagnostic value of apparent diffusion coefficient (ADC) maps in magnetic resonance imaging (MRI) in the volume of acute cerebral infarction (ACI). A total of 207 ACI patients were selected in our study. The cerebral infarction (CI) volume in the initial diffusion-weighted imaging examination, minimum ADC value, relative apparent diffusion coefficient (rADC) value, and mean ADC value were measured. The correlations between age, smoking, drinking, hypertension, diabetes, coronary heart disease, clinical stage, the lowest ADC value, the mean ADC value, and the mean rADC value with CI volume were analyzed by logistic regression analysis. A receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of the ADC value in the ACI volume. There was a significant difference in the distribution of the CI volume in ACI patients (P <.05). A significant difference was found in the signal intensity and percentage distribution of ADC map in patients of different CI groups with different CI volumes (P <.05). The signal of the ADC map was positively correlated with the CI volume. The mean ADC and rADC values had significant differences between different CI volumes (all P <.05). Logistic regression analysis revealed that the mean ADC value was significantly correlated with the CI volume (P <.05). Analysis of the ROC curve showed that the quantitative value of ADC has a diagnostic value for the ACI volume. This study has shown that the signal intensity change on the ADC map in MRI and quantitative analysis of the ADC value can be used as a reference for predicting the ACI volume. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  10. Perennial snow and ice volumes on Iliamna Volcano, Alaska, estimated with ice radar and volume modeling

    USGS Publications Warehouse

    Trabant, Dennis C.

    1999-01-01

    The volume of four of the largest glaciers on Iliamna Volcano was estimated using the volume model developed for evaluating glacier volumes on Redoubt Volcano. The volume model is controlled by simulated valley cross sections that are constructed by fitting third-order polynomials to the shape of the valley walls exposed above the glacier surface. Critical cross sections were field checked by sounding with ice-penetrating radar during July 1998. The estimated volumes of perennial snow and glacier ice for Tuxedni, Lateral, Red, and Umbrella Glaciers are 8.6, 0.85, 4.7, and 0.60 cubic kilometers respectively. The estimated volume of snow and ice on the upper 1,000 meters of the volcano is about 1 cubic kilometer. The volume estimates are thought to have errors of no more than ?25 percent. The volumes estimated for the four largest glaciers are more than three times the total volume of snow and ice on Mount Rainier and about 82 times the total volume of snow and ice that was on Mount St. Helens before its May 18, 1980 eruption. Volcanoes mantled by substantial snow and ice covers have produced the largest and most catastrophic lahars and floods. Therefore, it is prudent to expect that, during an eruptive episode, flooding and lahars threaten all of the drainages heading on Iliamna Volcano. On the other hand, debris avalanches can happen any time. Fortunately, their influence is generally limited to the area within a few kilometers of the summit.

  11. Correlation of ultrasound estimated placental volume and umbilical cord blood volume in term pregnancy

    PubMed Central

    Pannopnut, Papinwit; Kitporntheranunt, Maethaphan; Paritakul, Panwara; Kongsomboon, Kittipong

    2015-01-01

    Objective To investigate the correlation between ultrasound measured placental volume and collected umbilical cord blood (UCB) volume in term pregnancy. Material and Methods An observational cross-sectional study of term singleton pregnant women in the labor ward at Maha Chakri Sirindhorn Medical Center was conducted. Placental thickness, height, and width were measured using two-dimensional (2D) ultrasound and calculated for placental volume using the volumetric mathematic model. After the delivery of the baby, UCB was collected and measured for its volume immediately. Then, birth weight, placental weight, and the actual placental volume were analyzed. The Pearson’s correlation was used to determine the correlation between each two variables. Results A total of 35 pregnant women were eligible for the study. The mean and standard deviation of estimated placental volume and actual placental volume were 534±180 mL and 575±118 mL, respectively. The median UCB volume was 140 mL (range 98–220 mL). The UCB volume did not have a statistically significant correlation with the estimated placental volume (correlation coefficient 0.15; p=0.37). However, the UCB volume was significantly correlated with the actual placental volume (correlation coefficient 0.62; p<0.001) and birth weight (correlation coefficient 0.38; p=0.02). Conclusion The estimated placental volume by 2D ultrasound was not significantly correlated with the UCB volume. Further studies to establish the correlation between the UCB volume and the estimated placental volume using other types of placental imaging may be needed. PMID:26097385

  12. Estimating value and volume of ponderosa pine trees by equations.

    Treesearch

    Martin E. Plank

    1981-01-01

    Equations for estimating the selling value and tally volume for ponderosa pine lumber from the standing trees are described. Only five characteristics are required for the equations. Development and application of the system are described.

  13. Intra-thoracic fat volume is associated with myocardial infarction in patients with metabolic syndrome

    PubMed Central

    2013-01-01

    Background Visceral adiposity is increased in those with Metabolic Syndrome (MetS) and atherosclerotic disease burden. In this study we evaluate for associations between intra-thoracic fat volume (ITFV) and myocardial infarction (MI) in patients with MetS. Methods Ninety-four patients with MetS, MI or both were identified from a cardiovascular CMR clinical registry. MetS was defined in accordance to published guidelines; where-as MI was defined as the presence of subendocardial-based injury on late gadolinium enhancement imaging in a coronary vascular distribution. A healthy control group was also obtained from the same registry. Patients were selected into the following groups: MetS+/MI- (N = 32), MetS-/MI + (N = 30), MetS+/MI + (N = 32), MetS-/MI- (N = 16). ITFV quantification was performed using signal threshold analysis of sequential sagittal CMR datasets (HASTE) and indexed to body mass index. Results The mean age of the population was 59.8 ± 12.5 years. MetS+ patients (N=64) demonstrated a significantly higher indexed ITFV compared to MetS- patients (p = 0.05). Patients in respective MetS-/MI-, MetS+/MI-, MetS-/MI+, and MetS+/MI + study groups demonstrated a progressive elevation in the indexed ITFV (22.3 ± 10.6, 28.6 ± 12.6, 30.6 ± 12.3, and 35.2 ± 11.4 ml/kg/m2, (p = 0.002)). Among MetS+ patients those with MI showed a significantly higher indexed ITFV compared to those without MI (p = 0.02). Conclusions ITFV is elevated in patients with MetS and incrementally elevated among those with evidence of prior ischemic myocardial injury. Accordingly, the quantification of ITFV may be a valuable marker of myocardial infarction risk among patients with MetS and warrants further investigation. PMID:24020829

  14. Budget estimates fiscal year 1995: Volume 10

    SciTech Connect

    Not Available

    1994-02-01

    This report contains the Nuclear Regulatory Commission (NRC) fiscal year budget justification to Congress. The budget provides estimates for salaries and expenses and for the Office of the Inspector General for fiscal year 1995. The NRC 1995 budget request is $546,497,000. This is an increase of $11,497,000 above the proposed level for FY 1994. The NRC FY 1995 budget request is 3,218 FTEs. This is a decrease of 75 FTEs below the 1994 proposed level.

  15. Quantitative CT: technique dependence of volume estimation on pulmonary nodules.

    PubMed

    Chen, Baiyu; Barnhart, Huiman; Richard, Samuel; Colsher, James; Amurao, Maxwell; Samei, Ehsan

    2012-03-07

    Current estimation of lung nodule size typically relies on uni- or bi-dimensional techniques. While new three-dimensional volume estimation techniques using MDCT have improved size estimation of nodules with irregular shapes, the effect of acquisition and reconstruction parameters on accuracy (bias) and precision (variance) of the new techniques has not been fully investigated. To characterize the volume estimation performance dependence on these parameters, an anthropomorphic chest phantom containing synthetic nodules was scanned and reconstructed with protocols across various acquisition and reconstruction parameters. Nodule volumes were estimated by a clinical lung analysis software package, LungVCAR. Precision and accuracy of the volume assessment were calculated across the nodules and compared between protocols via a generalized estimating equation analysis. Results showed that the precision and accuracy of nodule volume quantifications were dependent on slice thickness, with different dependences for different nodule characteristics. Other parameters including kVp, pitch, and reconstruction kernel had lower impact. Determining these technique dependences enables better volume quantification via protocol optimization and highlights the importance of consistent imaging parameters in sequential examinations.

  16. Quantitative CT: technique dependence of volume estimation on pulmonary nodules

    NASA Astrophysics Data System (ADS)

    Chen, Baiyu; Barnhart, Huiman; Richard, Samuel; Colsher, James; Amurao, Maxwell; Samei, Ehsan

    2012-03-01

    Current estimation of lung nodule size typically relies on uni- or bi-dimensional techniques. While new three-dimensional volume estimation techniques using MDCT have improved size estimation of nodules with irregular shapes, the effect of acquisition and reconstruction parameters on accuracy (bias) and precision (variance) of the new techniques has not been fully investigated. To characterize the volume estimation performance dependence on these parameters, an anthropomorphic chest phantom containing synthetic nodules was scanned and reconstructed with protocols across various acquisition and reconstruction parameters. Nodule volumes were estimated by a clinical lung analysis software package, LungVCAR. Precision and accuracy of the volume assessment were calculated across the nodules and compared between protocols via a generalized estimating equation analysis. Results showed that the precision and accuracy of nodule volume quantifications were dependent on slice thickness, with different dependences for different nodule characteristics. Other parameters including kVp, pitch, and reconstruction kernel had lower impact. Determining these technique dependences enables better volume quantification via protocol optimization and highlights the importance of consistent imaging parameters in sequential examinations.

  17. Infarct Volume Prediction by Early Magnetic Resonance Imaging in a Murine Stroke Model Depends on Ischemia Duration and Time of Imaging.

    PubMed

    Leithner, Christoph; Füchtemeier, Martina; Jorks, Devi; Mueller, Susanne; Dirnagl, Ulrich; Royl, Georg

    2015-11-01

    Despite standardization of experimental stroke models, final infarct sizes after middle cerebral artery occlusion (MCAO) vary considerably. This introduces uncertainties in the evaluation of drug effects on stroke. Magnetic resonance imaging may detect variability of surgically induced ischemia before treatment and thus improve treatment effect evaluation. MCAO of 45 and 90 minutes induced brain infarcts in 83 mice. During, and 3 and 6 hours after MCAO, we performed multiparametric magnetic resonance imaging. We evaluated time courses of cerebral blood flow, apparent diffusion coefficient (ADC), T1, T2, accuracy of infarct prediction strategies, and impact on statistical evaluation of experimental stroke studies. ADC decreased during MCAO but recovered completely on reperfusion after 45 and partially after 90-minute MCAO, followed by a secondary decline. ADC lesion volumes during MCAO or at 6 hours after MCAO largely determined final infarct volumes for 90 but not for 45 minutes MCAO. The majority of chance findings of final infarct volume differences in random group allocations of animals were associated with significant differences in early ADC lesion volumes for 90, but not for 45-minute MCAO. The prediction accuracy of early magnetic resonance imaging for infarct volumes depends on timing of magnetic resonance imaging and MCAO duration. Variability of the posterior communicating artery in C57Bl6 mice contributes to differences in prediction accuracy between short and long MCAO. Early ADC imaging may be used to reduce errors in the interpretation of post MCAO treatment effects on stroke volumes. © 2015 American Heart Association, Inc.

  18. CTA collateral score predicts infarct volume and clinical outcome after endovascular therapy for acute ischemic stroke: a retrospective chart review.

    PubMed

    Elijovich, Lucas; Goyal, Nitin; Mainali, Shraddha; Hoit, Dan; Arthur, Adam S; Whitehead, Matthew; Choudhri, Asim F

    2016-06-01

    Acute ischemic stroke (AIS) due to emergent large-vessel occlusion (ELVO) has a poor prognosis. To examine the hypothesis that a better collateral score on pretreatment CT angiography (CTA) would correlate with a smaller final infarct volume and a more favorable clinical outcome after endovascular therapy (EVT). A retrospective chart review of the University of Tennessee AIS database from February 2011 to February 2013 was conducted. All patients with CTA-proven LVO treated with EVT were included. Recanalization after EVT was defined by Thrombolysis in Cerebral Infarction (TICI) score ≥2. Favorable outcome was assessed as a modified Rankin Score ≤3. Fifty patients with ELVO were studied. The mean National Institutes of Health Stroke Scale score was 17 (2-27) and 38 of the patients (76%) received intravenous tissue plasminogen activator. The recanalization rate for EVT was 86.6%. Good clinical outcome was achieved in 32% of patients. Univariate predictors of good outcome included good collateral scores (CS) on presenting CTA (p=0.043) and successful recanalization (p=0.02). Multivariate analysis confirmed both good CS (p=0.024) and successful recanalization (p=0.009) as predictors of favorable outcome. Applying results of the multivariate analysis to our cohort we were able to determine the likelihood of good clinical outcome as well as predictors of smaller final infarct volume after successful recanalization. Good CS predict smaller infarct volumes and better clinical outcome in patients recanalized with EVT. These data support the use of this technique in selecting patients for EVT. Poor CS should be considered as an exclusion criterion for EVT as patients with poor CS have poor clinical outcomes despite recanalization. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  19. Comparison of ASAT, CK, CK-MB, and LD for the estimation of acute myocardial infarct size in man.

    PubMed

    Grande, P; Christiansen, C; Alstrup, K

    1983-03-14

    The purpose of this study was to set up a simple and reliable procedure for estimating acute myocardial infarct (AMI) size by measuring serum enzymes in a few daily blood samples. Peak enzyme values and estimated infarct size from one, two, or three daily samples of aspartate aminotransferase (ASAT), creatine kinase (CK), CK-MB, and lactate dehydrogenase (LD) were compared with the extent of myocardial necrosis measured at autopsy in 22 patients who died from AMI. The correlation between the extent of the necrosis measured and peak serum enzymes from one daily blood sample was highest for CK-MB (r = 0.78) and LD (r = 0.73) compared to CK (r = 0.68) and ASAT (r = 0.67). To obtain a significant correlation, however, two patients had to be excluded from the ASAT and LD analyses. No significant improvement was obtained by more frequent blood sampling. Estimation of infarct size did not improve the correlation significantly for any enzyme, although the coefficient of correlation for CK-MB increased slightly (r = 0.83). Serum CK-MB determination provides a semiquantitative estimate of infarct size, but the other enzymes may give erroneous estimates owing to lesser cardiospecificity.

  20. Contaminated Soil Volume Estimation at the Maywood Site - 12292

    SciTech Connect

    Johnson, Robert; Quinn, John; Durham, Lisa; Moore, James; Hays, David

    2012-07-01

    As part of the ongoing remediation process at the Maywood Formerly Utilized Sites Remedial Action Program properties, Argonne National Laboratory assisted the U.S. Army Corps of Engineers (USACE) New York District in revising contaminated soil volume estimates for the remaining areas of the Stepan/Sears properties that require soil remediation. As part of the volume estimation process, an initial conceptual site model (ICSM) was prepared for the entire site that captured existing information (with the exception of soil sampling results) pertinent to the possible location of surface and subsurface contamination above cleanup requirements. This ICSM was based on historical anecdotal information, aerial photographs, and the logs from several hundred soil cores that identified the depth of fill material and the depth to bedrock under the site. Specialized geostatistical software developed by Argonne was used to update the ICSM with historical sampling results and down-hole gamma survey information for hundreds of soil core locations; both sampling results and down-hole gamma data were coded to identify whether the results indicated the presence of contamination above site cleanup requirements. Significant effort was invested in developing complete electronic data sets for the site by incorporating data contained in various scanned documents, maps, etc. The updating process yielded both a best guess estimate of contamination volumes and upper and lower bounds on the volume estimate that reflected the estimate's uncertainty. The site-wide contaminated volume estimate (with associated uncertainty) was adjusted to reflect areas where remediation was complete; the result was a revised estimate of the remaining soil volumes requiring remediation that the USACE could use for planning. Other environmental projects may benefit from this process for estimating the volume of contaminated soil. A comparison of sample and DHG results for various stations with the site ICSM provides

  1. Comparison of volume estimation methods for pancreatic islet cells

    NASA Astrophysics Data System (ADS)

    Dvořák, JiřÃ.­; Å vihlík, Jan; Habart, David; Kybic, Jan

    2016-03-01

    In this contribution we study different methods of automatic volume estimation for pancreatic islets which can be used in the quality control step prior to the islet transplantation. The total islet volume is an important criterion in the quality control. Also, the individual islet volume distribution is interesting -- it has been indicated that smaller islets can be more effective. A 2D image of a microscopy slice containing the islets is acquired. The input of the volume estimation methods are segmented images of individual islets. The segmentation step is not discussed here. We consider simple methods of volume estimation assuming that the islets have spherical or ellipsoidal shape. We also consider a local stereological method, namely the nucleator. The nucleator does not rely on any shape assumptions and provides unbiased estimates if isotropic sections through the islets are observed. We present a simulation study comparing the performance of the volume estimation methods in different scenarios and an experimental study comparing the methods on a real dataset.

  2. Role of the Molar Volume on Estimated Diffusion Coefficients

    NASA Astrophysics Data System (ADS)

    Santra, Sangeeta; Paul, Aloke

    2015-09-01

    The role of the molar volume on the estimated diffusion parameters has been speculated for decades. The Matano-Boltzmann method was the first to be developed for the estimation of the variation of the interdiffusion coefficients with composition. However, this could be used only when the molar volume varies ideally or remains constant. Although there are no such systems, this method is still being used to consider the ideal variation. More efficient methods were developed by Sauer-Freise, Den Broeder, and Wagner to tackle this problem. However, there is a lack of research indicating the most efficient method. We have shown that Wagner's method is the most suitable one when the molar volume deviates from the ideal value. Similarly, there are two methods for the estimation of the ratio of intrinsic diffusion coefficients at the Kirkendall marker plane proposed by Heumann and van Loo. The Heumann method, like the Matano-Boltzmann method, is suitable to use only when the molar volume varies more or less ideally or remains constant. In most of the real systems, where molar volume deviates from the ideality, it is safe to use the van Loo method. We have shown that the Heumann method introduces large errors even for a very small deviation of the molar volume from the ideal value. On the other hand, the van Loo method is relatively less sensitive to it. Overall, the estimation of the intrinsic diffusion coefficient is more sensitive than the interdiffusion coefficient.

  3. Volume estimation in a sequence of freehand ultrasound images

    NASA Astrophysics Data System (ADS)

    Zhang, Hongmei; Wan, Mingxi; Shen, Bo; Wang, Xiaodong; Lu, Mingzhu

    2006-11-01

    Volume estimation is particularly important in clinical medicine. Accurate volume estimation can provide quantitative information from which the follow-up therapy can be derived. In this paper, an efficient approach to volume estimation in a sequence of freehand ultrasound images is proposed. By integral of vector areas along the path of centroids of serial cross-sections, 3D volume estimation can be represented as 2D area calculation, where a fast mapping algorithm generating 2D representation is presented so that the position of interpolation points can be calculated with high efficiency. Meanwhile, to improve the accuracy, the cubic spline with second-order continuity is proposed for interpolation of 2D representation. Volume estimation on simulating phantoms for parallel cutting, fan cutting and random cuttings is provided. The experimental results show that the 2D representation generated by the fast mapping algorithm is highly efficient with less than 0.001 ms for 100 cross-sections. Quantitative comparisons show that the proposed interpolation method can approximate the original volume more precisely as compared to the Catmull-Rom (CR) spline, especially in the case of small number of cross-sections. In all cases, our approach can obtain accurate results at an error of less than 2% for ten cross-sections. Additionally, volume estimation on a high intensity focused ultrasound (HIFU) lesion based on linear B-scan and rotational B-scan sequential images are also performed. The experiments show that the proposed approach is promising and may have potential in clinical applications.

  4. A simple brain atrophy measure improves the prediction of malignant middle cerebral artery infarction by acute DWI lesion volume.

    PubMed

    Beck, Christoph; Kruetzelmann, Anna; Forkert, Nils D; Juettler, Eric; Singer, Oliver C; Köhrmann, Martin; Kersten, Jan F; Sobesky, Jan; Gerloff, Christian; Fiehler, Jens; Schellinger, Peter D; Röther, Joachim; Thomalla, Götz

    2014-06-01

    In patients with malignant middle cerebral artery infarction (MMI) decompressive surgery within 48 h improves functional outcome. In this respect, early identification of patients at risk of developing MMI is crucial. While the acute diffusion weighted imaging (DWI) lesion volume was found to predict MMI with high predictive values, the potential impact of preexisting brain atrophy on the course of space-occupying middle cerebral artery (MCA) infarction and the development of MMI remains unclear. We tested the hypothesis that the combination of the acute DWI lesion volume with simple measures of brain atrophy improves the early prediction of MMI. Data from a prospective, multicenter, observational study, which included patients with acute middle cerebral artery main stem occlusion studied by MRI within 6 h of symptom onset, was analyzed retrospectively. The development of MMI was defined according to the European randomized controlled trials of decompressive surgery. Acute DWI lesion volume, as well as brain and cerebrospinal fluid volume (CSF) were delineated. The intercaudate distance (ICD) was assessed as a linear brain atrophy marker by measuring the hemi-ICD of the intact hemisphere to account for local brain swelling. Binary logistic regression analysis was used to identify significant predictors of MMI. Cut-off values were determined by Classification and Regression Trees analysis. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the resulting models were calculated. Twenty-one (18 %) of 116 patients developed a MMI. Malignant middle cerebral artery infarctions patients had higher National Institutes of Health Stroke Scale scores on admission and presented more often with combined occlusion of the internal carotid artery and MCA. There were no differences in brain and CSF volume between the two groups. Diffusion weighted imaging lesion volume was larger (p < 0.001), while hemi-ICD was smaller (p = 0.029) in

  5. Estimation of infarct size by determination of myocardial 3H-tetracycline accumulation in the coronary ligated rat

    SciTech Connect

    Modrak, J.B.; Rovang, K.S.

    1981-10-01

    Myocardial infarction was produced in rats by ligation of the left coronary artery. Rats were injected with 3H-tetracycline (50 muCi/kg) i.p., 10 minutes prior to ligation. The rats were killed at various time periods after ligation and the myocardial accumulation of 3H-tetracycline determined in the left ventricle or in whole heart homogenates. CPK was also determined in the myocardium or serum. Myocardial 3H-tetracycline was not significantly elevated in the whole heart homogenates. However, there was a significant increase in 3H-tetracycline in the digests of the left ventricle 6 h post-infarct. This increase correlated very well with serum CPK activity. This suggest that this method could be a useful tool in the estimation of infarct size.

  6. Noninvasive estimation of regional myocardial oxygen consumption by positron emission tomography with carbon-11 acetate in patients with myocardial infarction

    SciTech Connect

    Walsh, M.N.; Geltman, E.M.; Brown, M.A.; Henes, C.G.; Weinheimer, C.J.; Sobel, B.E.; Bergmann, S.R. )

    1989-11-01

    We previously demonstrated in experimental studies that myocardial oxygen consumption (MVO2) can be estimated noninvasively with positron emission tomography (PET) from analysis of the myocardial turnover rate constant (k) after administration of carbon-11 (11C) acetate. To determine regional k in healthy human subjects and to estimate alterations in MVO2 accompanying myocardial ischemia, we administered (11C)acetate to five healthy human volunteers and to six patients with myocardial infarction. Extraction of (11C)acetate by the myocardium was avid and clearance from the blood-pool rapid yielding myocardial images of excellent quality. Regional k was homogeneous in myocardium of healthy volunteers (coefficient variation = 11%). In patients, k in regions remote from the area of infarction was not different from values in myocardium of healthy human volunteers (0.061 +/- 0.025 compared with 0.057 +/- 0.008 min-1). In contrast, MVO2 in the center of the infarct region was only 6% of that in remote regions (p less than 0.01). In four patients studied within 48 hr of infarction and again more than seven days after the acute event, regional k and MVO2 did not change. The approach developed should facilitate evaluation of the efficacy of interventions designed to enhance recovery of jeopardized myocardium and permit estimation of regional MVO2 and metabolic reserve underlying cardiac disease of diverse etiologies.

  7. Dose-volume histogram prediction using density estimation.

    PubMed

    Skarpman Munter, Johanna; Sjölund, Jens

    2015-09-07

    Knowledge of what dose-volume histograms can be expected for a previously unseen patient could increase consistency and quality in radiotherapy treatment planning. We propose a machine learning method that uses previous treatment plans to predict such dose-volume histograms. The key to the approach is the framing of dose-volume histograms in a probabilistic setting.The training consists of estimating, from the patients in the training set, the joint probability distribution of some predictive features and the dose. The joint distribution immediately provides an estimate of the conditional probability of the dose given the values of the predictive features. The prediction consists of estimating, from the new patient, the distribution of the predictive features and marginalizing the conditional probability from the training over this. Integrating the resulting probability distribution for the dose yields an estimate of the dose-volume histogram.To illustrate how the proposed method relates to previously proposed methods, we use the signed distance to the target boundary as a single predictive feature. As a proof-of-concept, we predicted dose-volume histograms for the brainstems of 22 acoustic schwannoma patients treated with stereotactic radiosurgery, and for the lungs of 9 lung cancer patients treated with stereotactic body radiation therapy. Comparing with two previous attempts at dose-volume histogram prediction we find that, given the same input data, the predictions are similar.In summary, we propose a method for dose-volume histogram prediction that exploits the intrinsic probabilistic properties of dose-volume histograms. We argue that the proposed method makes up for some deficiencies in previously proposed methods, thereby potentially increasing ease of use, flexibility and ability to perform well with small amounts of training data.

  8. Psychosocial work environment and myocardial infarction: improving risk estimation by combining two complementary job stress models in the SHEEP Study.

    PubMed

    Peter, R; Siegrist, J; Hallqvist, J; Reuterwall, C; Theorell, T

    2002-04-01

    Associations between two alternative formulations of job stress derived from the effort-reward imbalance and the job strain model and first non-fatal acute myocardial infarction were studied. Whereas the job strain model concentrates on situational (extrinsic) characteristics the effort-reward imbalance model analyses distinct person (intrinsic) characteristics in addition to situational ones. In view of these conceptual differences the hypothesis was tested that combining information from the two models improves the risk estimation of acute myocardial infarction. 951 male and female myocardial infarction cases and 1147 referents aged 45-64 years of The Stockholm Heart Epidemiology (SHEEP) case-control study underwent a clinical examination. Information on job stress and health adverse behaviours was derived from standardised questionnaires. Multivariate analysis showed moderately increased odds ratios for either model. Yet, with respect to the effort-reward imbalance model gender specific effects were found: in men the extrinsic component contributed to risk estimation, whereas this was the case with the intrinsic component in women. Controlling each job stress model for the other in order to test the independent effect of either approach did not show systematically increased odds ratios. An improved estimation of acute myocardial infarction risk resulted from combining information from the two models by defining groups characterised by simultaneous exposure to effort-reward imbalance and job strain (men: odds ratio 2.02 (95% confidence intervals (CI) 1.34 to 3.07); women odds ratio 2.19 (95% CI 1.11 to 4.28)). Findings show an improved risk estimation of acute myocardial infarction by combining information from the two job stress models under study. Moreover, gender specific effects of the two components of the effort-reward imbalance model were observed.

  9. On the significance of estimating thallium lung uptake images in patients with acute myocardial infarction

    SciTech Connect

    Tanaka, T.; Kimata, S.; Hirosawa, K.; Kusakabe, K.; Shigeta, T.; Ito, Y.; Shimizu, Y.; Tanaka, T.; Abe, M.; Matsuda, M.

    1984-01-01

    To determine whether thallium lung uptake images (TLI) can be used as a noninvasive method to estimate any of hemodynamic changes in patients (pts) with acute myocardial infarction (AMI) TLI were evaluated in 23 pts with AMI. All pts underwent multigated blood pool imaging and cardiac catheterization. TLI were estimated by comparing the intensity of T1-201 activity in the lower right lung with maximal myocardial count (thallium lung heart ratio; LHR). Pts with AMI were classified to 3 grades according to LHR. The classifications were hemodynamically significant. The specificity of LHR <0.6 for mPw <18mmHg was 100% (10/10). The specificity of LHR greater than or equal to 0.8 for mPw greater than or equal to 18mmHg was 85% (11/13) and for EF greater than or equal to 30% was 100% (13/13). The pts with LHR 0.8 showed high mortality (4/9) and high morbidity (all survivors were in NYHA class 2-3 and receiving digitalis and diuretics). TLI were easily obtained after routine T1-myocardial imaging, i.e. another 5 minutes imaging yielded clinically useful information for separating high and low-risk groups of pts with AMI.

  10. Relationship Between Infarct Volume and Prothrombin Time-International Normalized Ratio in Ischemic Stroke Patients With Nonvalvular Atrial Fibrillation.

    PubMed

    Matsumoto, Mari; Sakaguchi, Manabu; Okazaki, Shuhei; Hashikawa, Kazuo; Takahashi, Tsutomu; Matsumoto, Masayasu; Ohtsuki, Toshiho; Shimazu, Takeshi; Yoshimine, Toshiki; Mochizuki, Hideki; Kitagawa, Kazuo

    2017-02-24

    In Japan, warfarin treatment at prothrombin time-international normalized ratio (PT-INR) of 1.60-2.60 is recommended for elderly patients with nonvalvular atrial fibrillation (NVAF). But it remains unknown whether PT-INR 1.60-1.99 has a similar effect on stroke severity as a value >2.0. The purpose of this study was to clarify the association between infarct volume and PT-INR levels.Methods and Results:The 180 patients (mean age, 76 years [SD, 10 years], 53% male) selected from 429 consecutive ischemic stroke patients admitted within 48 h of onset between 2004 and 2014 with NVAF were included. We classified them into 4 groups according to their PT-INR values on admission: no warfarin (NW), 129 patients; PT-INR <1.60 (poor control: PC), 29 patients; PT-INR 1.60-1.99 (low-intensity control: LC), 14 patients; and PT-INR ≥2.00 (high-intensity control: HC), 8 patients. Median (interquartile range: IQR) of infarct volume was 55 mL (IQR 14-175) in the NW, 42 mL (IQR 27-170) in the PC, 36 mL (IQR 6-130) in the LC, and 11 mL (IQR 0-39) in the HC groups. The infarct volume of the HC group was significantly smaller than in the other 3 groups, but no difference existed between the LC and PC groups or the LC and NW groups. Warfarin control at PT-INR of 1.60-1.99 is not effective for reducing the severity of ischemic stroke in NVAF patients.

  11. Mean platelet volume and the risk of periprocedural myocardial infarction in patients undergoing coronary angioplasty.

    PubMed

    Verdoia, Monica; Camaro, Cyril; Barbieri, Lucia; Schaffer, Alon; Marino, Paolo; Bellomo, Giorgio; Suryapranata, Harry; De Luca, Giuseppe

    2013-05-01

    Periprocedural myocardial infarction (PMI) represents a relatively common complication of percutaneous coronary intervention (PCI). Mean platelet volume (MPV) has been proposed as a marker for platelet activation, as larger sized platelets have been associated with higher pro-thrombotic risk. Therefore, aim of the current study was to evaluate whether MPV is associated with increased risk of PMI after PCI. We included 1056 consecutive patients undergoing PCI. We measured myonecrosis biomarkers at intervals from 6 to 48 h after PCI. Periprocedural myonecrosis was defined for troponin I increase by 3 times the ULN or by 50% if elevated at the time of the procedure. PMI was defined as CK-MB increase by 3 times the ULN or 50% if elevated at the time of the procedure. We grouped patients according to tertiles values of MPV (<10.4 fl; 10.5-11.3 fl; >11.4 fl). High MPV was associated with diabetes (p = 0.025) and higher prevalence of cerebrovascular events (p = 0.005). MPV significantly related with haemoglobin levels (p < 0.001), but inversely to platelet count (p < 0.001) and higher presence of thrombus (p = 0.03). Larger sized platelets did not increase risk of periprocedural myonecrosis (p = 0.91; OR[95% CI] = 1.04[0.90-1.2], p = 0.64) or PMI (p = 0.09; OR[95%IC] = 1.13[0.93-1.37]; p = 0.20). Subgroup analysis confirmed no impact of MPV on periprocedural MI also in high-risk subsets of patients, such as those with ACS at presentation (OR[95%CI] = 1.09 [0.87-1.38]; p = 0.44), diabetes (OR[95% CI] = 1.02[0.71-1.47], p = 0.91), female gender (OR [95% CI] = 1.15 [0.78-1.71], p = 0.48), elderly patients (age ≥ 75 years) (OR[95%CI] = 1.21[0.87-1.69], p = 0.25) or with renal failure (OR[95%CI] = 1.55[0.91-2.61], p = 0.1). This study demonstrates that MPV does not predict the risk of PMI in patients undergoing PCI. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  12. Automated quantification of myocardial infarction from MR images by accounting for partial volume effects: animal, phantom, and human study.

    PubMed

    Heiberg, Einar; Ugander, Martin; Engblom, Henrik; Götberg, Matthias; Olivecrona, Göran K; Erlinge, David; Arheden, Håkan

    2008-02-01

    Ethics committees approved human and animal study components; informed written consent was provided (prospective human study [20 men; mean age, 62 years]) or waived (retrospective human study [16 men, four women; mean age, 59 years]). The purpose of this study was to prospectively evaluate a clinically applicable method, accounting for the partial volume effect, to automatically quantify myocardial infarction from delayed contrast material-enhanced magnetic resonance images. Pixels were weighted according to signal intensity to calculate infarct fraction for each pixel. Mean bias +/- variability (or standard deviation), expressed as percentage left ventricular myocardium (%LVM), were -0.3 +/- 1.3 (animals), -1.2 +/- 1.7 (phantoms), and 0.3 +/- 2.7 (patients), respectively. Algorithm had lower variability than dichotomous approach (2.7 vs 7.7 %LVM, P < .01) and did not differ from interobserver variability for bias (P = .31) or variability (P = .38). The weighted approach provides automatic quantification of myocardial infarction with higher accuracy and lower variability than a dichotomous algorithm. (c) RSNA, 2007.

  13. Factors Affecting Prostate Volume Estimation in Computed Tomography Images

    SciTech Connect

    Yang, Cheng-Hsiu; Wang, Shyh-Jen; Lin, Alex Tong-Long; Lin, Chao-An

    2011-04-01

    The aim of this study was to investigate how apex-localizing methods and the computed tomography (CT) slice thickness affected the CT-based prostate volume estimation. Twenty-eight volunteers underwent evaluations of prostate volume by CT, where the contour segmentations were performed by three observers. The bottom of ischial tuberosities (ITs) and the bulb of the penis were used as reference positions to locate the apex, and the distances to the apex were recorded as 1.3 and 2.0 cm, respectively. Interobserver variations to locate ITs and the bulb of the penis were, on average, 0.10 cm (range 0.03-0.38 cm) and 0.30 cm (range 0.00-0.98 cm), respectively. The range of CT slice thickness varied from 0.08-0.48 cm and was adopted to examine the influence of the variation on volume estimation. The volume deviation from the reference case (0.08 cm), which increases in tandem with the slice thickness, was within {+-} 3 cm{sup 3}, regardless of the adopted apex-locating reference positions. In addition, the maximum error of apex identification was 1.5 times of slice thickness. Finally, based on the precise CT films and the methods of apex identification, there were strong positive correlation coefficients for the estimated prostate volume by CT and the transabdominal ultrasonography, as found in the present study (r > 0.87; p < 0.0001), and this was confirmed by Bland-Altman analysis. These results will help to identify factors that affect prostate volume calculation and to contribute to the improved estimation of the prostate volume based on CT images.

  14. Estimation of myocardial volume at risk from CT angiography

    NASA Astrophysics Data System (ADS)

    Zhu, Liangjia; Gao, Yi; Mohan, Vandana; Stillman, Arthur; Faber, Tracy; Tannenbaum, Allen

    2011-03-01

    The determination of myocardial volume at risk distal to coronary stenosis provides important information for prognosis and treatment of coronary artery disease. In this paper, we present a novel computational framework for estimating the myocardial volume at risk in computed tomography angiography (CTA) imagery. Initially, epicardial and endocardial surfaces, and coronary arteries are extracted using an active contour method. Then, the extracted coronary arteries are projected onto the epicardial surface, and each point on this surface is associated with its closest coronary artery using the geodesic distance measurement. The likely myocardial region at risk on the epicardial surface caused by a stenosis is approximated by the region in which all its inner points are associated with the sub-branches distal to the stenosis on the coronary artery tree. Finally, the likely myocardial volume at risk is approximated by the volume in between the region at risk on the epicardial surface and its projection on the endocardial surface, which is expected to yield computational savings over risk volume estimation using the entire image volume. Furthermore, we expect increased accuracy since, as compared to prior work using the Euclidean distance, we employ the geodesic distance in this work. The experimental results demonstrate the effectiveness of the proposed approach on pig heart CTA datasets.

  15. Temporal validation for landsat-based volume estimation model

    Treesearch

    Renaldo J. Arroyo; Emily B. Schultz; Thomas G. Matney; David L. Evans; Zhaofei Fan

    2015-01-01

    Satellite imagery can potentially reduce the costs and time associated with ground-based forest inventories; however, for satellite imagery to provide reliable forest inventory data, it must produce consistent results from one time period to the next. The objective of this study was to temporally validate a Landsat-based volume estimation model in a four county study...

  16. Comparison of Standing Volume Estimates Using Optical Dendrometers

    Treesearch

    Neil A. Clark; Stanley J. Zarnoch; Alexander Clark; Gregory A. Reams

    2001-01-01

    This study compared height and diameter measurements and volume estimates on 20 hardwood and 20 softwood stems using traditional optical dendrometers, an experimental camera instrument, and mechanical calipers. Multiple comparison tests showed significant differences among the means for lower stem diameters when the camera was used. There were no significant...

  17. Comparison of standing volume estimates using optical dendrometers

    Treesearch

    Neil A. Clark; Stanley J. Zarnoch; Alexander Clark; Gregory A. Reams

    2001-01-01

    This study compared height and diameter measurements and volume estimates on 20 hardwood and 20 softwood stems using traditional optical dendrometers, an experimental camera instrument, and mechanical calipers. Multiple comparison tests showed significant differences among the means for lower stem diameters when the camera was used. There were no significant...

  18. Alternatives to estimate statewide changes in aspen cover type volumes

    Treesearch

    Curtis L. VanderSchaaf

    2015-01-01

    For Minnesota, the only data available to conduct regional or state-wide level assessments across all ownerships is the Forest Inventory and Analysis Program (FIA). Some of the many alternatives available to estimate regional changes in standing volume are referred to here as 1.) FIA alternative, 2.) a commonly applied growth and yield system referred to as Walters and...

  19. Intracranial volume estimated with commonly used methods could introduce bias in studies including brain volume measurements.

    PubMed

    Nordenskjöld, Richard; Malmberg, Filip; Larsson, Elna-Marie; Simmons, Andrew; Brooks, Samantha J; Lind, Lars; Ahlström, Håkan; Johansson, Lars; Kullberg, Joel

    2013-12-01

    In brain volumetric studies, intracranial volume (ICV) is often used as an estimate of pre-morbid brain size as well as to compensate for inter-subject variations in head size. However, if the estimated ICV is biased by for example gender or atrophy, it could introduce errors in study results. To evaluate how two commonly used methods for ICV estimation perform, computer assisted reference segmentations were created and evaluated. Segmentations were created for 399 MRI volumes from 75-year-old subjects, with 53 of these subjects having an additional scan and segmentation created at age 80. ICV estimates from Statistical Parametric Mapping (SPM, version 8) and Freesurfer (FS, version 5.1.0) were compared to the reference segmentations, and bias related to skull size (approximated with the segmentation measure), gender or atrophy were tested for. The possible ICV related effect on associations between normalized hippocampal volume and factors gender, education and cognition was evaluated by normalizing hippocampal volume with different ICV measures. Excellent agreement was seen for inter- (r=0.999) and intra- (r=0.999) operator reference segmentations. Both SPM and FS overestimated ICV. SPM showed bias associated with gender and atrophy while FS showed bias dependent on skull size. All methods showed good correlation between time points in the longitudinal data (reference: 0.998, SPM: 0.962, FS: 0.995). Hippocampal volume showed different associations with cognition and gender depending on which ICV measure was used for hippocampal volume normalization. These results show that the choice of method used for ICV estimation can bias results in studies including brain volume measurements. © 2013. Published by Elsevier Inc. All rights reserved.

  20. Estimating outcomes of astronauts with myocardial infarction in exploration class space missions.

    PubMed

    Gillis, David B; Hamilton, Douglas R

    2012-02-01

    We estimate likelihood of presenting rhythms and survival to hospital discharge outcome after acute cardiac ischemia with arrhythmia and/or myocardial infarction (AMI) during long-duration space missions (LDSM) using selected terrestrial cohorts in medical literature. Medical scenarios were risk-stratified by coronary artery calcium score (CAC) and Framingham risk factors (FRF). AMI with and without sudden cardiac arrest (SCA) likelihoods and clinically significant rhythm scenarios and associated outcomes in "astronaut-like" cohorts were derived from two prospective trials identified by an evidence-based literature review. Results are presented using an event sequence diagram and event time line. The association of increasing CAC scores and FRF with AMI and SCA outcomes was calculated. Low AMI likelihoods are estimated in individuals with CAC scores of zero or < 100 and a low number of FRF. Survival rate to hospital discharge after out of hospital SCA in a large urban environment study was 5.2%. EMS-witnessed ventricular tachycardia and/or ventricular fibrillation survival rate of 37.5% represents < 1% of all urban out of hospital AMI, and these patients have a high proportion of known ischemic cardiovascular and pulmonary disease "disqualifying for spaceflight." Multiple factors may be expected to delay or defeat rapid access to "chain of survival" resources during LDSM, lowering survival rates below urban levels of 5.2%. Low CAC and FRF reflect lower risk for AMI events. Zero CAC was associated with the lowest risk of AMI after 3.5 yr of follow-up. Quantifiable incidence and outcome characterization suggests AMI in LDSM outcomes will be relatively independent of in-flight medical resources.

  1. Estimating flood hydrographs and volumes for Alabama streams

    USGS Publications Warehouse

    Olin, D.A.; Atkins, J.B.

    1988-01-01

    The hydraulic design of highway drainage structures involves an evaluation of the effect of the proposed highway structures on lives, property, and stream stability. Flood hydrographs and associated flood volumes are useful tools in evaluating these effects. For design purposes, the Alabama Highway Department needs information on flood hydrographs and volumes associated with flood peaks of specific recurrence intervals (design floods) at proposed or existing bridge crossings. This report will provide the engineer with a method to estimate flood hydrographs, volumes, and lagtimes for rural and urban streams in Alabama with drainage areas less than 500 sq mi. Existing computer programs and methods to estimate flood hydrographs and volumes for ungaged streams have been developed in Georgia. These computer programs and methods were applied to streams in Alabama. The report gives detailed instructions on how to estimate flood hydrographs for ungaged rural or urban streams in Alabama with drainage areas less than 500 sq mi, without significant in-channel storage or regulations. (USGS)

  2. Novel whole brain segmentation and volume estimation using quantitative MRI.

    PubMed

    West, J; Warntjes, J B M; Lundberg, P

    2012-05-01

    Brain segmentation and volume estimation of grey matter (GM), white matter (WM) and cerebro-spinal fluid (CSF) are important for many neurological applications. Volumetric changes are observed in multiple sclerosis (MS), Alzheimer's disease and dementia, and in normal aging. A novel method is presented to segment brain tissue based on quantitative magnetic resonance imaging (qMRI) of the longitudinal relaxation rate R(1), the transverse relaxation rate R(2) and the proton density, PD. Previously reported qMRI values for WM, GM and CSF were used to define tissues and a Bloch simulation performed to investigate R(1), R(2) and PD for tissue mixtures in the presence of noise. Based on the simulations a lookup grid was constructed to relate tissue partial volume to the R(1)-R(2)-PD space. The method was validated in 10 healthy subjects. MRI data were acquired using six resolutions and three geometries. Repeatability for different resolutions was 3.2% for WM, 3.2% for GM, 1.0% for CSF and 2.2% for total brain volume. Repeatability for different geometries was 8.5% for WM, 9.4% for GM, 2.4% for CSF and 2.4% for total brain volume. We propose a new robust qMRI-based approach which we demonstrate in a patient with MS. • A method for segmenting the brain and estimating tissue volume is presented • This method measures white matter, grey matter, cerebrospinal fluid and remaining tissue • The method calculates tissue fractions in voxel, thus accounting for partial volume • Repeatability was 2.2% for total brain volume with imaging resolution <2.0 mm.

  3. Magma generation on Mars: Estimated volumes through time

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald; Schneid, B.

    1991-01-01

    Images of volcanoes and lava flows, chemical analysis by the Viking landers, and studies of meteorites show that volcanism has played an important role in the evolution of Mars. Photogeologic mapping suggests that half of Mars' surface is covered with volcanic materials. Here, researchers present results from new mappings, including estimates of volcanic deposit thicknesses based on partly buried and buried impact craters using the technique of DeHon. The researchers infer the volumes of possible associated plutonic rocks and derive the volumes of magmas on Mars generated in its post-crustal formation history. Also considered is the amount of juvenile water that might have exsolved from the magma through time.

  4. Modeling Approach for Estimating Co-Produced Water Volumes and Saltwater Disposal Volumes in Oklahoma

    NASA Astrophysics Data System (ADS)

    Murray, K. E.

    2016-12-01

    Management of produced fluids has become an important issue in Oklahoma because large volumes of saltwater are co-produced with oil and gas, and disposed into saltwater disposal wells at high rates. Petroleum production increased from 2009-2015, especially in central and north-central Oklahoma where the Mississippian and Hunton zones were redeveloped using horizontal wells and dewatering techniques that have led to a disproportional increase in produced water volumes. Improved management of co-produced water, including desalination for beneficial reuse and decreased saltwater disposal volumes, is only possible if spatial and temporal trends can be defined and related to the producing zones. It is challenging to quantify the volumes of co-produced water by region or production zone because co-produced water volumes are generally not reported. Therefore, the goal of this research is to estimate co-produced water volumes for 2008-present with an approach that can be replicated as petroleum production shifts to other regions. Oil and gas production rates from subsurface zones were multiplied by ratios of H2O:oil and H2O:gas for the respective zones. Initial H2O:oil and H2O:gas ratios were adjusted/calibrated, by zone, to maximize correlation of county-scale produced H2O estimates versus saltwater disposal volumes from 2013-2015. These calibrated ratios were then used to compute saltwater disposal volumes from 2008-2012 because of apparent data gaps in reported saltwater disposal volumes during that timeframe. This research can be used to identify regions that have the greatest need for produced water treatment systems. The next step in management of produced fluids is to explore optimal energy-efficient strategies that reduce deleterious effects.

  5. Satellite sensor estimates of Northern Hemisphere snow volume

    NASA Technical Reports Server (NTRS)

    Chang, A. T. C.; Foster, J. L.; Hall, D. K.

    1990-01-01

    In the Northern Hemisphere the mean monthly snow-covered area ranges from about 7 percent of the land area in summer to over 40 percent in winter, thus making snow one of the most rapidly varying natural surface features. The mean monthly snow volume ranges from about 1.5 x 10 to the 16th g in summer to about 3.0 x 10 to the 18th g in winter. Currently several algorithms utilizing passive microwave brightness temperatures are available to estimate snow cover and depth. The algorithm presented here uses the difference between the 37-GHz channel and the 18-GHz channel of the SMMR on the Nimbus-7 satellite to derive estimates of snow volume. Even though satellite sensor snow records are currently too short to reveal trends, continued monitoring over about the next 10 years should make it possible to establish whether incipient or current trends are significant in the context of global climate change.

  6. Bearing Estimation Uncertainties for the Volume Search Sonar

    DTIC Science & Technology

    2009-08-31

    II bathymetric sidescan sonar system”, IEEE Journal of Oceanic Engineering, 17(3), 239-251, 1992. R. O. Nielsen, “Accuracy of angle estimation with...shows potential for detecting variations in sediment type in much the same manner that a sidescan sonar detects these variations. However, this data...code) 31/08/2009 Final / Technical 2003 - Aug. 2008 Acoustic Signal Processing for Ocean Mapping Applications With The Volume Search Sonar (VSS

  7. Estimation of liquid volume fraction using ultrasound transit time spectroscopy

    NASA Astrophysics Data System (ADS)

    Al-Qahtani, Saeed M.; Langton, Christian M.

    2016-12-01

    It has recently been proposed that the propagation of an ultrasound wave through complex structures, consisting of two-materials of differing ultrasound velocity, may be considered as an array of parallel ‘sonic rays’, the transit time of each determined by their relative proportion; being a minimum (t min) in entire higher velocity material, and a maximum (t max) in entire lower velocity material. An ultrasound transit time spectrum (UTTS) describes the proportion of sonic rays at an individual transit time. It has previously been demonstrated that the solid volume fraction of a solid:liquid composite, specifically acrylic step-wedges immersed in water, may be reliably estimated from the UTTS. The aim of this research was to investigate the hypothesis that the volume fraction of a two-component liquid mixture, of unequal ultrasound velocity, may also be estimated by UTTS. A through-transmission technique incorporating two 1 MHz ultrasound transducers within a horizontally-aligned cylindrical tube-housing was utilised, the proportion of silicone oil to water being varied from 0% to 100%. The liquid volume fraction was estimated from the UTTS at each composition, the coefficient of determination (R 2%) being 98.9  ±  0.7%. The analysis incorporated a novel signal amplitude normalisation technique to compensate for absorption within the silicone oil. It is therefore envisaged that the parallel sonic ray concept and the derived UTTS may be further applied to the quantification of liquid mixture composition assessment.

  8. Guidelines for estimating volume, biomass, and smoke production for piled slash.

    Treesearch

    Colin C. Hardy

    1998-01-01

    Guidelines in the form of a six-step approach are provided for estimating volumes, oven-dry mass, consumption, and particulate matter emissions for piled logging debris. Seven stylized pile shapes and their associated geometric volume formulae are used to estimate gross pile volumes. The gross volumes are then reduced to net wood volume by applying an appropriate wood-...

  9. Variability of standard liver volume estimation versus software-assisted total liver volume measurement.

    PubMed

    Pomposelli, James J; Tongyoo, Assanee; Wald, Christoph; Pomfret, Elizabeth A

    2012-09-01

    The estimation of the standard liver volume (SLV) is an important component of the evaluation of potential living liver donors and the surgical planning for resection for tumors. At least 16 different formulas for estimating SLV have been published in the worldwide literature. More recently, several proprietary software-assisted image postprocessing (SAIP) programs have been developed to provide accurate volume measurements based on the actual anatomy of a specific patient. Using SAIP, we measured SLV in 375 healthy potential liver donors and compared the results to SLV values that were estimated with the previously published formulas and each donor's demographic and anthropomorphic data. The percentage errors of the 16 SLV formulas versus SAIP varied by more than 59% (from -21.6% to +37.7%). One formula was not statistically different from SAIP with respect to the percentage error (-1.2%), and another formula was not statistically different with respect to the absolute liver volume (18 mL). More than 75% of the estimated SLV values produced by these 2 formulas had percentage errors within ±15%, and the formulas provided good predictions within acceptable agreement (±15%) on scatter plots. Because of the wide variability, care must be taken when a formula is being chosen for estimating SLV, but the 2 aforementioned formulas provided the most accurate results with our patient demographics.

  10. Estimated Glomerular Filtration Rate in Short-Risk Stratification in Acute Myocardial Infarction

    PubMed Central

    Blasco, Luisa; Sanjuan, Rafael; Carbonell, Nieves; Solís, Miguel A.; Puchades, María J.; Torregrosa, Isidro; Miguel, Juan A.

    2011-01-01

    Background/Aims Renal dysfunction is associated with a higher risk of cardiovascular disease in patients with acute myocardial infarction (AMI). The aim of this study was to investigate the independent prognostic value of renal dysfunction and its incremental predictability risk after adjusting for well-known clinical factors in patients with AMI. Methods 751 consecutive patients with AMI admitted to the Coronary Care Unit (CCU) were included. Patients were grouped into 2 categories according to the baseline estimated glomerular filtration rate (eGFR) on admission (eGFR <60 vs. eGFR ≥60 ml/min/1.73 m2). C-reactive protein and white blood cell count (WBC) as well as clinical prognostic variables were assessed. The endpoint was mortality during CCU stay. The discriminatory power was estimated by the C-index. Results The patient group with an eGFR <60 ml/min/1.73 m2 was older, had more cardiovascular risk factors, a lower left ventricular ejection fraction and higher cardiovascular mortality during CCU stay (13 vs. 3%). Logistic regression analysis revealed the following predictors of mortality: degree of renal impairment (eGFR <60 ml/min/1.73 m2), hazard ratio (HR) = 2.2 (95% CI 1.1–4.3; p = 0.028); WBC >11,000 × 106/l, HR = 2.3 (95% CI 1.2–4.5; p = 0.017); Killip class on admission, HR = 3.8 (95% CI 1.7–8.5; p = 0.001), and New York Heart Association Functional Classification, HR = 3.6 (95% CI 1.7–7.4; p = 0.001). The adjusted C-index was 0.78 for baseline clinical variables and 0.84 for eGFR. Conclusions In patients with AMI, decreased eGFR is an important prognostic factor for impaired cardiac function and mortality in the short-term follow-up. The eGFR may be reliably used in the risk stratification of patients with AMI. PMID:22258400

  11. A Comparison of Height-Accumulation and Volume-Equation Methods for Estimating Tree and Stand Volumes

    Treesearch

    R.B. Ferguson; V. Clark Baldwin

    1995-01-01

    Estimating tree and stand volume in mature plantations is time consuming, involving much manpower and equipment; however, several sampling and volume-prediction techniques are available. This study showed that a well-constructed, volume-equation method yields estimates comparable to those of the often more time-consuming, height-accumulation method, even though the...

  12. Prediction of infarct volume and neurologic outcome by using automated multiparametric perfusion-weighted magnetic resonance imaging in a primate model of permanent middle cerebral artery occlusion.

    PubMed

    Sasaki, Makoto; Kudo, Kohsuke; Honjo, Kaneyoshi; Hu, Jin-Qing; Wang, Hai-Bin; Shintaku, Katsuya

    2011-02-01

    By optimizing thresholds, we identified the perfusion-weighted magnetic resonance imaging (PWI) parameters that accurately predict final infarct volume and neurologic outcome in a primate model of permanent middle cerebral artery (MCA) occlusion. Ten cynomolgus monkeys underwent PWI and diffusion-weighted imaging (DWI) at 3 and 47 hours, respectively, after right MCA occlusion using platinum coils, and were killed at 48 hours. Volumes of the hypoperfused areas on PWI were automatically measured using different thresholds and 11 parametric maps to determine the optimum threshold (at which least difference was found between the average volumes on PWI and those determined using specimens or DWI). In the case of arrival time (AT), cerebral blood volume (CBV), time to peak (TTP), time to maximum (T(max)), and cerebral blood flow (CBF) determined using deconvolution techniques, the volume of the hypoperfused area significantly correlated with the infarct volumes and the neurologic deficit scores with small variations, whereas in the case of mean transit time and nondeconvolution CBF, relatively poor correlations with large variations were seen. At optimum threshold, AT, CBV, TTP, T(max), and deconvolution CBF can accurately predict the final infarct volume and neurologic outcome in monkeys with permanent MCA occlusion.

  13. Regulatory T cells modulate inflammation and reduce infarct volume in experimental brain ischaemia

    PubMed Central

    Brea, David; Agulla, Jesús; Rodríguez-Yáñez, Manuel; Barral, David; Ramos-Cabrer, Pedro; Campos, Francisco; Almeida, Angeles; Dávalos, Antoni; Castillo, José

    2014-01-01

    Brain ischaemia (stroke) triggers an intense inflammatory response predominately mediated by the accumulation of inflammatory cells and mediators in the ischaemic brain. In this context, regulatory T (Treg) cells, a subpopulation of CD4+ T cells with immunosuppressive and anti-inflammatory properties, are activated in the late stages of the disease. To date, the potential therapeutic usefulness of Treg cells has not been tested. In this study, we aimed to investigate whether Treg cells exert protection/repair following stroke. Both the adoptive transfer of Treg cells into ischaemic rats and the stimulation of endogenous T-cell proliferation using a CD28 superagonist reduced the infarct size at 3–28 days following the ischaemic insult. Moreover, T cell-treated animals had higher levels of FoxP3 and lower levels of IL-1β, CD11b+ and CD68+ cells in the infarcted hemisphere when compared with control animals. However, T-cell treatment did not alter the rate of proliferation of NeuN-, NCAM- or CD31-positive cells, thereby ruling out neurogenesis and angiogenesis in protection. These results suggest that adoptive transfer of T cells is a promising therapeutic strategy against the neurological consequences of stroke. PMID:24889329

  14. Early Activation of Phosphatidylinositol 3-Kinase after Ischemic Stroke Reduces Infarct Volume and Improves Long-Term Behavior.

    PubMed

    Kim, Young Seo; Yoo, Arum; Son, Jeong Woo; Kim, Hyun Young; Lee, Young-Jun; Hwang, Sejin; Lee, Kyu-Yong; Lee, Young Joo; Ayata, Cenk; Kim, Hyung-Hwan; Koh, Seong-Ho

    2017-09-01

    Phosphatidylinositol 3-kinases (PI3Ks) have recently been implicated in apoptosis and ischemic cell death. We tested the efficacy of early intervention with a peptide PI3K activator in focal cerebral ischemia. After determining the most effective dose (24 μg/kg) and time window (2 h after MCAO) of treatment, a total of 48 rats were subjected to middle cerebral artery occlusion (MCAO). Diffusion weighted MRI (DWI) was performed 1 h after MCAO and rats with lesion sizes within a predetermined range were randomized to either PI3K activator or vehicle treatment arms. Fluid attenuated inversion recovery (FLAIR) MRI, neurological function, western blots, and immunohistochemistry were blindly assessed. Initial DWI lesion volumes were nearly identical between two groups prior to treatment. However, FLAIR showed significantly smaller infarct volumes in the PI3K activator group compared with vehicle (146 ± 81 mm(3) and 211 ± 96 mm(3), p = 0.045) at 48 h. The PI3K activator group also had better neurological function for up to 2 weeks. In addition, PI3K activator decreased the number of TUNEL-positive cells in the peri-infarct region compared with the control group. Western blot and immunohistochemistry showed increased expression of phosphorylated Akt (Ser473) and GSK-3β (Ser9) and decreased expression of cleaved caspase-9 and caspase-3. Our results suggest a neuroprotective role of early activation of PI3K in ischemic stroke. The use of DWI in the randomization of experimental groups may reduce bias.

  15. Unsupervised partial volume estimation using 3D and statistical priors

    NASA Astrophysics Data System (ADS)

    Tardif, Pierre M.

    2001-07-01

    Our main objective is to compute the volume of interest of images from magnetic resonance imaging (MRI). We suggest a method based on maximum a posteriori. Using texture models, we propose a new partial volume determination. We model tissues using generalized gaussian distributions fitted from a mixture of their gray levels and texture information. Texture information relies on estimation errors from multiresolution and multispectral autoregressive models. A uniform distribution solves large estimation errors, when dealing with unknown tissues. An initial segmentation, needed by the multiresolution segmentation deterministic relaxation algorithm, is found using an anatomical atlas. To model the a priori information, we use a full 3-D extension of Markov random fields. Our 3-D extension is straightforward, easily implemented, and includes single label probability. Using initial segmentation map and initial tissues models, iterative updates are made on the segmentation map and tissue models. Updating tissue models remove field inhomogeneities. Partial volumes are computed from final segmentation map and tissue models. Preliminary results are encouraging.

  16. Comparison of Estimation Methods for Creating Small Area Rates of Acute Myocardial Infarction Among Medicare Beneficiaries in California

    PubMed Central

    Arcaya, Mariana C.; Subramanian, S.V.

    2016-01-01

    Creating local population health measures from administrative data would be useful for health policy and public health monitoring purposes. While a wide range of options – from simple spatial smoothers to model-based methods – for estimating such rates exists, there are relatively few side-by-side comparisons, especially not with real-world data. In this paper, we compare methods for creating local estimates of acute myocardial infarction rates from Medicare claims data. A Bayesian Monte Carlo Markov Chain estimator that incorporated spatial and local random effects performed best, followed by a method-of-moments spatial Empirical Bayes estimator. As the former is more complicated and time-consuming, spatial linear Empirical Bayes methods may represent a good alternative for non-specialist investigators. PMID:26291680

  17. Comparison of estimation methods for creating small area rates of acute myocardial infarction among Medicare beneficiaries in California.

    PubMed

    Yasaitis, Laura C; Arcaya, Mariana C; Subramanian, S V

    2015-09-01

    Creating local population health measures from administrative data would be useful for health policy and public health monitoring purposes. While a wide range of options--from simple spatial smoothers to model-based methods--for estimating such rates exists, there are relatively few side-by-side comparisons, especially not with real-world data. In this paper, we compare methods for creating local estimates of acute myocardial infarction rates from Medicare claims data. A Bayesian Monte Carlo Markov Chain estimator that incorporated spatial and local random effects performed best, followed by a method-of-moments spatial Empirical Bayes estimator. As the former is more complicated and time-consuming, spatial linear Empirical Bayes methods may represent a good alternative for non-specialist investigators.

  18. Gas Flaring Volume Estimates with Multiple Satellite Observations

    NASA Astrophysics Data System (ADS)

    Ziskin, D. C.; Elvidge, C.; Baugh, K.; Ghosh, T.; Hsu, F. C.

    2010-12-01

    Flammable gases (primarily methane) are a common bi-product associated with oil wells. Where there is no infrastructure to use the gas or bring it to market, the gases are typically flared off. This practice is more common at remote sites, such as an offshore drilling platform. The Defense Meteorological Satellite Program (DMSP) is a series of satellites with a low-light imager called the Operational Linescan System (OLS). The OLS, which detects the flares at night, has been a valuable tool in the estimation of flared gas volume [Elvidge et al, 2009]. The use of the Moderate Resolution Imaging Spectroradiometer (MODIS) fire product has been processed to create products suitable for an independent estimate of gas flaring on land. We are presenting the MODIS flare product, the results of our MODIS gas flare volume analysis, and independent validation of the published DMSP estimates. Elvidge, C. D., Ziskin, D., Baugh, K. E., Tuttle, B. T., Ghosh, T., Pack, D. W., Erwin, E. H., Zhizhin, M., 2009, "A Fifteen Year Record of Global Natural Gas Flaring Derived from Satellite Data", Energies, 2 (3), 595-622

  19. Acoustic source inversion to estimate volume flux from volcanic explosions

    NASA Astrophysics Data System (ADS)

    Kim, Keehoon; Fee, David; Yokoo, Akihiko; Lees, Jonathan M.

    2015-07-01

    We present an acoustic waveform inversion technique for infrasound data to estimate volume fluxes from volcanic eruptions. Previous inversion techniques have been limited by the use of a 1-D Green's function in a free space or half space, which depends only on the source-receiver distance and neglects volcanic topography. Our method exploits full 3-D Green's functions computed by a numerical method that takes into account realistic topographic scattering. We apply this method to vulcanian eruptions at Sakurajima Volcano, Japan. Our inversion results produce excellent waveform fits to field observations and demonstrate that full 3-D Green's functions are necessary for accurate volume flux inversion. Conventional inversions without consideration of topographic propagation effects may lead to large errors in the source parameter estimate. The presented inversion technique will substantially improve the accuracy of eruption source parameter estimation (cf. mass eruption rate) during volcanic eruptions and provide critical constraints for volcanic eruption dynamics and ash dispersal forecasting for aviation safety. Application of this approach to chemical and nuclear explosions will also provide valuable source information (e.g., the amount of energy released) previously unavailable.

  20. Volume estimation of multi-density nodules with thoracic CT

    NASA Astrophysics Data System (ADS)

    Gavrielides, Marios A.; Li, Qin; Zeng, Rongping; Myers, Kyle J.; Sahiner, Berkman; Petrick, Nicholas

    2014-03-01

    The purpose of this work was to quantify the effect of surrounding density on the volumetric assessment of lung nodules in a phantom CT study. Eight synthetic multidensity nodules were manufactured by enclosing spherical cores in larger spheres of double the diameter and with a different uniform density. Different combinations of outer/inner diameters (20/10mm, 10/5mm) and densities (100HU/-630HU, 10HU/- 630HU, -630HU/100HU, -630HU/-10HU) were created. The nodules were placed within an anthropomorphic phantom and scanned with a 16-detector row CT scanner. Ten repeat scans were acquired using exposures of 20, 100, and 200mAs, slice collimations of 16x0.75mm and 16x1.5mm, and pitch of 1.2, and were reconstructed with varying slice thicknesses (three for each collimation) using two reconstruction filters (medium and standard). The volumes of the inner nodule cores were estimated from the reconstructed CT data using a matched-filter approach with templates modeling the characteristics of the multi-density objects. Volume estimation of the inner nodule was assessed using percent bias (PB) and the standard deviation of percent error (SPE). The true volumes of the inner nodules were measured using micro CT imaging. Results show PB values ranging from -12.4 to 2.3% and SPE values ranging from 1.8 to 12.8%. This study indicates that the volume of multi-density nodules can be measured with relatively small percent bias (on the order of +/-12% or less) when accounting for the properties of surrounding densities. These findings can provide valuable information for understanding bias and variability in clinical measurements of nodules that also include local biological changes such as inflammation and necrosis.

  1. Estimated personal soot exposure is associated with acute myocardial infarction onset in a case-crossover study.

    PubMed

    von Klot, Stephanie; Cyrys, Josef; Hoek, Gerard; Kühnel, Brigitte; Pitz, Mike; Kuhn, Ulrike; Kuch, Bernhard; Meisinger, Christa; Hörmann, Allmut; Wichmann, H-Erich; Peters, Annette

    2011-01-01

    The current study investigates the association of estimated personal exposure to traffic-related air pollution and acute myocardial infarction (AMI). Cases of AMI were interviewed in the Augsburg KORA Myocardial Infarction Registry from February 1999 through December 2003, and 960 AMI survivors were included in the analyses. The time-varying component of daily personal soot exposure (the temporally variable contribution due to the daily area level of exposure and daily personal activities) was estimated using a linear combination of estimated mean ambient soot concentration, time spent outdoors, and time spent in traffic. The association of soot exposure with AMI onset was estimated in a case-crossover analysis controlling for temperature and day of the week using conditional logistic regression analyses. Estimated personal soot exposure was associated with AMI (relative risk, 1.30 per 1.1 m(-1) × 10(-5) [95% confidence interval, 1.09-1.55]). Estimated ambient soot and measured ambient PM(2.5) particulate matter 2.5 µm and smaller in aerodynamic diameter were not significantly associated with AMI onset. Our results suggest that an increase in risk of AMI in association with personal soot exposure may be in great part due to the contribution of personal soot from individual times spent in traffic and individual times spent outdoors. As a consequence, estimates calculated based on measurements at urban background stations may be underestimations. Health effects of traffic-related air pollution may need to be updated, taking into account individual time spent in traffic and outdoors, to adequately protect the public.

  2. Estimating pore and cement volumes in thin section

    USGS Publications Warehouse

    Halley, R.B.

    1978-01-01

    Point count estimates of pore, grain and cement volumes from thin sections are inaccurate, often by more than 100 percent, even though they may be surprisingly precise (reproducibility + or - 3 percent). Errors are produced by: 1) inclusion of submicroscopic pore space within solid volume and 2) edge effects caused by grain curvature within a 30-micron thick thin section. Submicroscopic porosity may be measured by various physical tests or may be visually estimated from scanning electron micrographs. Edge error takes the form of an envelope around grains and increases with decreasing grain size and sorting, increasing grain irregularity and tighter grain packing. Cements are greatly involved in edge error because of their position at grain peripheries and their generally small grain size. Edge error is minimized by methods which reduce the thickness of the sample viewed during point counting. Methods which effectively reduce thickness include use of ultra-thin thin sections or acetate peels, point counting in reflected light, or carefully focusing and counting on the upper surface of the thin section.

  3. Motoneuronotrophic factor analog GM6 reduces infarct volume and behavioral deficits following transient ischemia in the mouse

    PubMed Central

    Yu, Jin; Zhu, Hong; Ko, Dorothy; Kindy, Mark S.

    2012-01-01

    Motoneuronotrophic factor (MNTF) is an endogenous neurotrophin that is highly specific for the human nervous system, and some of the observed effects of MNTF include motoneuron differentiation, maintenance, survival, and reinnervation of target muscles and organs. MNTF is a neuro-signaling molecule that binds to specific receptors. Using In Silico Analysis, one of the active sites of MNTF was identified as an analog of six amino acids (GM6). The effect of chemically synthesized GM6 on ischemic stroke was studied in the middle cerebral artery occlusion (MCAo) mouse model. Mice were subjected to 1 hour of ischemia followed by 24 hours of reperfusion. Mice were injected intravenously with a bolus of GM6, at various doses (1 and 5 mg/kg) immediately after the start of reperfusion and examined for changes in physiological parameters, neurological deficits and infarct volume. GM6 was able to penetrate the blood brain barrier, and at both 1 and 5 mg/kg showed a significant protection from infarct damage, which translated to improvement of neurological deficits. Administration of GM6 demonstrated no changes in HR, BP, pO2, pCO2, or pH. A significant increase over the control group in CBF after reperfusion was observed with GM6 administration, which helped to mitigate the ischemic effect caused by the blockage of blood flow. The time window of treatment was assessed at various times following cerebral ischemia with GM6 demonstrating a significant protective effect up to 6–12 hours post ischemia. In addition, GM6 increased neurogenesis, and decreased apoptosis and inflammation in the mouse brain following cerebral ischemic injury. These data suggest that GM6 is neuroprotective to the brain following IV injection in the mouse model of MCAo. PMID:18789909

  4. Fullerenols and glucosamine fullerenes reduce infarct volume and cerebral inflammation after ischemic stroke in normotensive and hypertensive rats.

    PubMed

    Fluri, Felix; Grünstein, Dan; Cam, Ertugrul; Ungethuem, Udo; Hatz, Florian; Schäfer, Juliane; Samnick, Samuel; Israel, Ina; Kleinschnitz, Christoph; Orts-Gil, Guillermo; Moch, Holger; Zeis, Thomas; Schaeren-Wiemers, Nicole; Seeberger, Peter

    2015-03-01

    Cerebral inflammation plays a crucial role in the pathophysiology of ischemic stroke and is involved in all stages of the ischemic cascade. Fullerene derivatives, such as fullerenol (OH-F) are radical scavengers acting as neuroprotective agents while glucosamine (GlcN) attenuates cerebral inflammation after stroke. We created novel glucosamine-fullerene conjugates (GlcN-F) to combine their protective effects and compared them to OH-F regarding stroke-induced cerebral inflammation and cellular damage. Fullerene derivatives or vehicle was administered intravenously in normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) immediately after transient middle cerebral artery occlusion (tMCAO). Infarct size was determined at day 5 and neurological outcome at days 1 and 5 after tMCAO. CD68- and NeuN-staining were performed to determine immunoreactivity and neuronal survival respectively. Cytokine and toll like receptor 4 (TLR-4) expression was assessed using quantitative real-time PCR. Magnetic resonance imaging revealed a significant reduction of infarct volume in both, WKY and SHR that were treated with fullerene derivatives. Treated rats showed an amelioration of neurological symptoms as both OH-F and GlcN-F prevented neuronal loss in the perilesional area. Cerebral immunoreactivity was reduced in treated WKY and SHR. Expression of IL-1β and TLR-4 was attenuated in OH-F-treated WKY rats. In conclusion, OH-F and GlcN-F lead to a reduction of cellular damage and inflammation after stroke, rendering these compounds attractive therapeutics for stroke.

  5. Myocardial Extracellular Volume Estimation by CMR Predicts Functional Recovery Following Acute MI.

    PubMed

    Kidambi, Ananth; Motwani, Manish; Uddin, Akhlaque; Ripley, David P; McDiarmid, Adam K; Swoboda, Peter P; Broadbent, David A; Musa, Tarique Al; Erhayiem, Bara; Leader, Joshua; Croisille, Pierre; Clarysse, Patrick; Greenwood, John P; Plein, Sven

    2017-09-01

    In the setting of reperfused acute myocardial infarction (AMI), the authors sought to compare prediction of contractile recovery by infarct extracellular volume (ECV), as measured by T1-mapping cardiac magnetic resonance (CMR), with late gadolinium enhancement (LGE) transmural extent. The transmural extent of myocardial infarction as assessed by LGE CMR is a strong predictor of functional recovery, but accuracy of the technique may be reduced in AMI. ECV mapping by CMR can provide a continuous measure associated with the severity of tissue damage within infarcted myocardium. Thirty-nine patients underwent acute (day 2) and convalescent (3 months) CMR scans following AMI. Cine imaging, tissue tagging, T2-weighted imaging, modified Look-Locker inversion T1 mapping natively and 15 min post-gadolinium-contrast administration, and LGE imaging were performed. The ability of acute infarct ECV and acute transmural extent of LGE to predict convalescent wall motion, ejection fraction (EF), and strain were compared per-segment and per-patient. Per-segment, acute ECV and LGE transmural extent were associated with convalescent wall motion score (p < 0.01; p < 0.01, respectively). ECV had higher accuracy than LGE extent to predict improved wall motion (area under receiver-operating characteristics curve 0.77 vs. 0.66; p = 0.02). Infarct ECV ≤0.5 had sensitivity 81% and specificity 65% for prediction of improvement in segmental function; LGE transmural extent ≤0.5 had sensitivity 61% and specificity 71%. Per-patient, ECV and LGE correlated with convalescent wall motion score (r = 0.45; p < 0.01; r = 0.41; p = 0.02, respectively) and convalescent EF (p < 0.01; p = 0.04). ECV and LGE extent were not significantly correlated (r = 0.34; p = 0.07). In multivariable linear regression analysis, acute infarct ECV was independently associated with convalescent infarct strain and EF (p = 0.03; p = 0.04), whereas LGE was not (p = 0.29; p = 0.24). Acute infarct ECV

  6. The free radical spin-trap alpha-PBN attenuates periinfarct depolarizations following permanent middle cerebral artery occlusion in rats without reducing infarct volume.

    PubMed

    Christensen, Thomas; Bruhn, Torben; Diemer, Nils Henrik

    2003-11-14

    The effect of the free radical spin-trap alpha-phenyl-butyl-tert-nitrone (alpha-PBN) in permanent focal cerebral ischemia in rats was examined in two series of experiments. In the first, rats were subjected to permanent occlusion of the middle cerebral artery (MCAO) and treated 1 h after occlusion with a single dose of alpha-PBN (100 mg/kg) or saline. Body temperature was measured and controlled for the first 24 h to obtain identical temperature curves in the two groups. Cortical infarct volumes were determined on histological sections 7 days later. alpha-PBN did not significantly reduce infarct volume (control: 28.3+/-16.3 mm3 vs. alpha-PBN 23.7+/-7.4 mm3). In the second series of experiments, periinfarct depolarizations (PIDs) were recorded with an extracellular DC electrode at two locations in the ischemic penumbra for the initial 3 h following MCAO. alpha-PBN (100 mg/kg, single dose in conjunction with occlusion) significantly reduced the total number (median value of 3 PIDs in the control groups vs. 1 PID in alpha-PBN groups, p<0.001) and total duration of the PIDs (median value 662 s in the control groups vs. 162 s in the alpha-PBN groups, p<0.006). In spite of this, cortical infarct volumes determined 7 days later in the same rats were not smaller in alpha-PBN-treated rats. The study thus demonstrates that attenuation of PIDs does not always lead to smaller infarcts if permanent arterial occlusion is followed by long survival time and does not support the hypothesis that PIDs per se are critical determinants of infarct size in this situation.

  7. Change in diffusion-weighted imaging infarct volume predicts neurologic outcome at 90 days: results of the Acute Stroke Accurate Prediction (ASAP) trial serial imaging substudy.

    PubMed

    Barrett, Kevin M; Ding, Yong Hong; Wagner, Douglas P; Kallmes, David F; Johnston, Karen C

    2009-07-01

    Predictive models of outcome after ischemic stroke have incorporated acute diffusion-weighted MRI (DWI) information with mixed results. We hypothesized that serial measurements of DWI infarct volume would be predictive of functional outcome after ischemic stroke. The prospective Acute Stroke Accurate Prediction (ASAP) Study included a prespecified serial imaging subgroup who underwent DWI studies at baseline (<24 hours after symptom onset) and Day 5 (+/-2 days). DWI infarct volumes were calculated using the Analyze software (Rochester, Minn). Clinical outcomes were assessed at 3 months. Univariate and multivariable regression analysis was performed to assess the relationship between change in DWI lesion volume and excellent neurological outcome (modified Rankin Scale 0, 1, and Barthel Index >or=95). In total, 169 cases from the ASAP study had serial DWI scans with a measurable lesion at baseline, follow-up, or both. The median baseline National Institutes of Health Stroke Scale score was 6 (interquartile range, 3 to 13). For each 10 cm(3) of growth in DWI infarct volume, the OR for achieving an excellent outcome by modified Rankin Scale was 0.52 (95% CI, 0.38 to 0.71) and for the Barthel Index was 0.64 (95% CI, 0.51 to 0.79). Adjusting for clinically important covariates, the OR for an excellent modified Rankin Scale outcome was 0.57 (95% CI, 0.37 to 0.88) and excellent Barthel Index outcome was 0.75 (95% CI, 0.56 to 1.01). Based on these data, the likelihood of achieving an excellent neurological outcome diminishes substantially with growth in DWI infarct volume in the first 5 days after ischemic stroke of mild to moderate severity.

  8. Rain volume estimation over areas using satellite and radar data

    NASA Technical Reports Server (NTRS)

    Doneaud, A. A.; Vonderhaar, T. H.

    1985-01-01

    An investigation of the feasibility of rain volume estimation using satellite data following a technique recently developed with radar data called the Arera Time Integral was undertaken. Case studies were selected on the basis of existing radar and satellite data sets which match in space and time. Four multicell clusters were analyzed. Routines for navigation remapping amd smoothing of satellite images were performed. Visible counts were normalized for solar zenith angle. A radar sector of interest was defined to delineate specific radar echo clusters for each radar time throughout the radar echo cluster lifetime. A satellite sector of interest was defined by applying small adjustments to the radar sector using a manual processing technique. The radar echo area, the IR maximum counts and the IR counts matching radar echo areas were found to evolve similarly, except for the decaying phase of the cluster where the cirrus debris keeps the IR counts high.

  9. Rain volume estimation over areas using satellite and radar data

    NASA Technical Reports Server (NTRS)

    Doneaud, A. A.; Vonderhaar, T. H.

    1985-01-01

    The feasibility of rain volume estimation over fixed and floating areas was investigated using rapid scan satellite data following a technique recently developed with radar data, called the Area Time Integral (ATI) technique. The radar and rapid scan GOES satellite data were collected during the Cooperative Convective Precipitation Experiment (CCOPE) and North Dakota Cloud Modification Project (NDCMP). Six multicell clusters and cells were analyzed to the present time. A two-cycle oscillation emphasizing the multicell character of the clusters is demonstrated. Three clusters were selected on each day, 12 June and 2 July. The 12 June clusters occurred during the daytime, while the 2 July clusters during the nighttime. A total of 86 time steps of radar and 79 time steps of satellite images were analyzed. There were approximately 12-min time intervals between radar scans on the average.

  10. Volume estimation of brain abnormalities in MRI data

    NASA Astrophysics Data System (ADS)

    Suprijadi, Pratama, S. H.; Haryanto, F.

    2014-02-01

    The abnormality of brain tissue always becomes a crucial issue in medical field. This medical condition can be recognized through segmentation of certain region from medical images obtained from MRI dataset. Image processing is one of computational methods which very helpful to analyze the MRI data. In this study, combination of segmentation and rendering image were used to isolate tumor and stroke. Two methods of thresholding were employed to segment the abnormality occurrence, followed by filtering to reduce non-abnormality area. Each MRI image is labeled and then used for volume estimations of tumor and stroke-attacked area. The algorithms are shown to be successful in isolating tumor and stroke in MRI images, based on thresholding parameter and stated detection accuracy.

  11. Rain volume estimation over areas using satellite and radar data

    NASA Technical Reports Server (NTRS)

    Doneaud, Andre A.; Vonderhaar, T. H.; Johnson, L. R.; Laybe, P.; Reinke, D.

    1987-01-01

    The analysis of 18 convective clusters demonstrates that the extension of the Area-Time-Integral (ATI) technique to the use of satellite data is possible. The differences of the internal structures of the radar reflectivity features, and of the satellite features, give rise to differences in estimating rain volumes by delineating area; however, by focusing upon the area integrated over the lifetime of the storm, it is suggested that some of the errors produced by the differences in the cloud geometries as viewed by radar or satellite are minimized. The results are good and future developments should consider data from different climatic regions and should allow for implementation of the technique in a general circulation model.

  12. Rapid surface-water volume estimations in beaver ponds

    NASA Astrophysics Data System (ADS)

    Karran, Daniel J.; Westbrook, Cherie J.; Wheaton, Joseph M.; Johnston, Carol A.; Bedard-Haughn, Angela

    2017-02-01

    Beaver ponds are surface-water features that are transient through space and time. Such qualities complicate the inclusion of beaver ponds in local and regional water balances, and in hydrological models, as reliable estimates of surface-water storage are difficult to acquire without time- and labour-intensive topographic surveys. A simpler approach to overcome this challenge is needed, given the abundance of the beaver ponds in North America, Eurasia, and southern South America. We investigated whether simple morphometric characteristics derived from readily available aerial imagery or quickly measured field attributes of beaver ponds can be used to approximate surface-water storage among the range of environmental settings in which beaver ponds are found. Studied were a total of 40 beaver ponds from four different sites in North and South America. The simplified volume-area-depth (V-A-h) approach, originally developed for prairie potholes, was tested. With only two measurements of pond depth and corresponding surface area, this method estimated surface-water storage in beaver ponds within 5 % on average. Beaver pond morphometry was characterized by a median basin coefficient of 0.91, and dam length and pond surface area were strongly correlated with beaver pond storage capacity, regardless of geographic setting. These attributes provide a means for coarsely estimating surface-water storage capacity in beaver ponds. Overall, this research demonstrates that reliable estimates of surface-water storage in beaver ponds only requires simple measurements derived from aerial imagery and/or brief visits to the field. Future research efforts should be directed at incorporating these simple methods into both broader beaver-related tools and catchment-scale hydrological models.

  13. Estimating stroke volume from oxygen pulse during exercise.

    PubMed

    Crisafulli, Antonio; Piras, Francesco; Chiappori, Paolo; Vitelli, Stefano; Caria, Marcello A; Lobina, Andrea; Milia, Raffaele; Tocco, Filippo; Concu, Alberto; Melis, Franco

    2007-10-01

    This investigation aimed at verifying whether it was possible to reliably assess stroke volume (SV) during exercise from oxygen pulse (OP) and from a model of arterio-venous oxygen difference (a-vO(2)D) estimation. The model was tested in 15 amateur male cyclists performing an exercise test on a cycle-ergometer consisting of a linear increase of workload up to exhaustion. Starting from the analysis of previous published data, we constructed a model of a-vO(2)D estimation (a-vO(2)D(est)) which predicted that the a-vO(2)D at rest was 30% of the total arterial O(2) content (CaO(2)) and that it increased linearly during exercise reaching a value of 80% of CaO(2) at the peak workload (W(max)) of cycle exercise. Then, the SV was calculated by applying the following equation, SV = OP/a-vO(2)D(est), where the OP was assessed as the oxygen uptake/heart rate. Data calculated by our model were compared with those obtained by impedance cardiography. The main result was that the limits of agreement between the SV assessed by impedance cardiography and the SV estimated were between 22.4 and -27.9 ml (+18.8 and -24% in terms of per cent difference between the two SV measures). It was concluded that our model for estimating SV during effort may be reasonably applicable, at least in a healthy population.

  14. Comparison of Statistically Modeled Contaminated Soil Volume Estimates and Actual Excavation Volumes at the Maywood FUSRAP Site - 13555

    SciTech Connect

    Moore, James; Hays, David; Quinn, John; Johnson, Robert; Durham, Lisa

    2013-07-01

    As part of the ongoing remediation process at the Maywood Formerly Utilized Sites Remedial Action Program (FUSRAP) properties, Argonne National Laboratory (Argonne) assisted the U.S. Army Corps of Engineers (USACE) New York District by providing contaminated soil volume estimates for the main site area, much of which is fully or partially remediated. As part of the volume estimation process, an initial conceptual site model (ICSM) was prepared for the entire site that captured existing information (with the exception of soil sampling results) pertinent to the possible location of surface and subsurface contamination above cleanup requirements. This ICSM was based on historical anecdotal information, aerial photographs, and the logs from several hundred soil cores that identified the depth of fill material and the depth to bedrock under the site. Specialized geostatistical software developed by Argonne was used to update the ICSM with historical sampling results and down-hole gamma survey information for hundreds of soil core locations. The updating process yielded both a best guess estimate of contamination volumes and a conservative upper bound on the volume estimate that reflected the estimate's uncertainty. Comparison of model results to actual removed soil volumes was conducted on a parcel-by-parcel basis. Where sampling data density was adequate, the actual volume matched the model's average or best guess results. Where contamination was un-characterized and unknown to the model, the actual volume exceeded the model's conservative estimate. Factors affecting volume estimation were identified to assist in planning further excavations. (authors)

  15. Estimating Intracranial Volume in Brain Research: An Evaluation of Methods.

    PubMed

    Sargolzaei, Saman; Sargolzaei, Arman; Cabrerizo, Mercedes; Chen, Gang; Goryawala, Mohammed; Pinzon-Ardila, Alberto; Gonzalez-Arias, Sergio M; Adjouadi, Malek

    2015-10-01

    Intracranial volume (ICV) is a standard measure often used in morphometric analyses to correct for head size in brain studies. Inaccurate ICV estimation could introduce bias in the outcome. The current study provides a decision aid in defining protocols for ICV estimation across different subject groups in terms of sampling frequencies that can be optimally used on the volumetric MRI data, and type of software most suitable for use in estimating the ICV measure. Four groups of 53 subjects are considered, including adult controls (AC, adults with Alzheimer's disease (AD), pediatric controls (PC) and group of pediatric epilepsy subjects (PE). Reference measurements were calculated for each subject by manually tracing intracranial cavity without sub-sampling. The reliability of reference measurements were assured through intra- and inter- variation analyses. Three publicly well-known software packages (FreeSurfer Ver. 5.3.0, FSL Ver. 5.0, SPM8 and SPM12) were examined in their ability to automatically estimate ICV across the groups. Results on sub-sampling studies with a 95 % confidence showed that in order to keep the accuracy of the inter-leaved slice sampling protocol above 99 %, sampling period cannot exceed 20 mm for AC, 25 mm for PC, 15 mm for AD and 17 mm for the PE groups. The study assumes a priori knowledge about the population under study into the automated ICV estimation. Tuning of the parameters in FSL and the use of proper atlas in SPM showed significant reduction in the systematic bias and the error in ICV estimation via these automated tools. SPM12 with the use of pediatric template is found to be a more suitable candidate for PE group. SPM12 and FSL subjected to tuning are the more appropriate tools for the PC group. The random error is minimized for FS in AD group and SPM8 showed less systematic bias. Across the AC group, both SPM12 and FS performed well but SPM12 reported lesser amount of systematic bias.

  16. Estimating Residual Solids Volume In Underground Storage Tanks

    SciTech Connect

    Clark, Jason L.; Worthy, S. Jason; Martin, Bruce A.; Tihey, John R.

    2014-01-08

    The Savannah River Site liquid waste system consists of multiple facilities to safely receive and store legacy radioactive waste, treat, and permanently dispose waste. The large underground storage tanks and associated equipment, known as the 'tank farms', include a complex interconnected transfer system which includes underground transfer pipelines and ancillary equipment to direct the flow of waste. The waste in the tanks is present in three forms: supernatant, sludge, and salt. The supernatant is a multi-component aqueous mixture, while sludge is a gel-like substance which consists of insoluble solids and entrapped supernatant. The waste from these tanks is retrieved and treated as sludge or salt. The high level (radioactive) fraction of the waste is vitrified into a glass waste form, while the low-level waste is immobilized in a cementitious grout waste form called saltstone. Once the waste is retrieved and processed, the tanks are closed via removing the bulk of the waste, chemical cleaning, heel removal, stabilizing remaining residuals with tailored grout formulations and severing/sealing external penetrations. The comprehensive liquid waste disposition system, currently managed by Savannah River Remediation, consists of 1) safe storage and retrieval of the waste as it is prepared for permanent disposition; (2) definition of the waste processing techniques utilized to separate the high-level waste fraction/low-level waste fraction; (3) disposition of LLW in saltstone; (4) disposition of the HLW in glass; and (5) closure state of the facilities, including tanks. This paper focuses on determining the effectiveness of waste removal campaigns through monitoring the volume of residual solids in the waste tanks. Volume estimates of the residual solids are performed by creating a map of the residual solids on the waste tank bottom using video and still digital images. The map is then used to calculate the volume of solids remaining in the waste tank. The ability to

  17. Association between epicardial adipose tissue volume and myocardial salvage in patients with a first ST-segment elevation myocardial infarction: An epicardial adipose tissue paradox.

    PubMed

    Gohbara, Masaomi; Iwahashi, Noriaki; Akiyama, Eiichi; Maejima, Nobuhiko; Tsukahara, Kengo; Hibi, Kiyoshi; Kosuge, Masami; Ebina, Toshiaki; Umemura, Satoshi; Kimura, Kazuo

    2016-11-01

    Epicardial adipose tissue (EAT), defined as the adipose tissue between the visceral pericardium and the outer margin of the myocardium, is associated with coronary artery disease in the general population. However, the clinical implications of EAT in patients with ST-segment elevation myocardial infarction (STEMI) remain unclear. A total of 142 patients with a first STEMI, who received reperfusion therapy within 12h from symptom onset, were enrolled. All patients underwent cardiac magnetic resonance imaging to evaluate infarct core (Core), area at risk (AAR), and EAT volume. Myocardial salvage index (MSI) was defined as AAR minus Core divided by AAR. Patients in the lower tertile of EAT volume were classified as the low EAT group (group L) and the other two-thirds as the high EAT group (group H). The mean MSI was lower in group L than in group H (0.43±0.13 vs 0.49±0.13, p=0.01), and the mean extent of Core was higher in group L than in group H (25±10% vs 19±10%, p<0.01). Multivariate linear regression analysis including coronary risk factors and previously reported predictors of infarct size demonstrated that EAT volume was an independent predictor of MSI (β coefficient=0.002 per 1mL, p=0.002). A lower EAT volume is associated with less myocardial salvage and larger infarct size in patients with a first STEMI. Copyright © 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

  18. Estimating exercise stroke volume from asymptotic oxygen pulse in humans.

    PubMed

    Whipp, B J; Higgenbotham, M B; Cobb, F C

    1996-12-01

    Noninvasive techniques have been devised to estimate cardiac output (Q) during exercise to obviate vascular cannulation. However, although these techniques are noninvasive, they are commonly not nonintrusive to subjects' spontaneous ventilation and gas-exchange responses. We hypothesized that the exercise stroke volume (SV) and, hence, Q might be accurately estimated simply from the response pattern of two standardly determined variables: O2 uptake (VO2) and heart rate (HR). Central to the theory is the demonstration that the product of Q and mixed venous O2 content is virtually constant (k) during steady-state exercise. Thus from the Fick equation, VO2 = Q.CaCO2-k, where CaCO2 is the arterial CO2 content, the O2 pulse (O2-P) equals SV.CaCO2-(k/HR). Because the arterial O2 content (CaO2) is usually relatively constant in normal subjects during exercise, O2-P should change hyperbolically with HR, asymptoting at SV.CaO2. In addition, because the asymptotic O2-P equals the slope (S) of the linear O2-HR relationship, exercise SV may be predicted as S/CaO2. We tested this prediction in 23 normal subjects who underwent a 3-min incremental cycle-ergometer test with direct determination of CaO2 and mixed venous O2 content from indwelling catheters. The predicted SV closely reflected the measured value (r = 0.80). We therefore conclude that, in normal subjects, exercise SV may be estimated simply as five times S of the linear VO2-HR relationship (where 5 is approximately 1/CaO2).

  19. Photogrammetry and Laser Imagery Tests for Tank Waste Volume Estimates: Summary Report

    SciTech Connect

    Field, Jim G.

    2013-03-27

    Feasibility tests were conducted using photogrammetry and laser technologies to estimate the volume of waste in a tank. These technologies were compared with video Camera/CAD Modeling System (CCMS) estimates; the current method used for post-retrieval waste volume estimates. This report summarizes test results and presents recommendations for further development and deployment of technologies to provide more accurate and faster waste volume estimates in support of tank retrieval and closure.

  20. Estimation of the volume-weighted mean nuclear volume discriminates Spitz's nevi from nodular malignant melanomas.

    PubMed

    Steiner, A; Binder, M; Mossbacher, U; Wolff, K; Pehamberger, H

    1994-03-01

    Spitz's nevi are benign melanocytic skin tumors that are usually differentiated from nodular malignant melanomas by histopathologic criteria. Often, however, the architectural pattern and cytologic features of Spitz's nevi and nodular melanomas are similar. Hence, Spitz's nevi may be confused with nodular malignant melanomas at the histopathologic level. The determination of volume-weighted mean nuclear volume (Vv) uses a technique that permits an unbiased and efficient estimation of nuclear volumes in tissues. In this study, Vv was determined in 13 Spitz's nevi and 14 nodular malignant melanomas to investigate whether this stereologic approach may be of use in the differentiation of these two tumors. Vv was determined by computer-assisted image analysis (IBAS 20, Kontron, Germany) on Feulgen-stained sections using stereologic estimation of the Vv. The Vv (+/- SD) of Spitz's nevi was 491.6 micron3 (SD +/- 175.1), whereas nodular malignant melanomas exhibit a significantly higher (p < 0.001) Vv of 775.2 micron3 (SD +/- 205.4). This difference was even more pronounced when the deeper portions of the lesions (Spitz's nevi: 443.1 micron3, SD +/- 142.4; nodular malignant melanomas: 864.1, SD +/- 169.6) were investigated. In addition, we found that in relation to the depth of the lesions the mean Vv decreased in Spitz's nevi, whereas it increased in nodular melanomas. We found that (i) nodular malignant melanomas reveal a larger Vv than Spitz's nevi in general, and (ii) in contrast to malignant melanomas, the Vv of nevomelanocytes in Spitz's nevi decreases in the deeper portions of the dermis. Thus, Vv may be regarded as a helpful tool for the differential diagnosis of Spitz's nevi and nodular malignant melanomas.

  1. In vitro evaluation of three-dimensional ultrasonography in volume estimation of abdominal organs.

    PubMed

    Gilja, O H; Thune, N; Matre, K; Hausken, T; Odegaard, S; Berstad, A

    1994-01-01

    The purpose of this study was to evaluate the accuracy and precision of a three-dimensional (3D) ultrasound system in volume estimation of abdominal organs in vitro. A mechanical sector scanner coupled to a stepping motor recorded images of porcine stomach and kidneys. The transducer was tilted through 88 degrees yielding 81 frames, and volume estimation was performed digitally after interactive manual contour indication and organ reconstruction in 3 dimensions. This 3D system showed good correlation (r = 0.998) between estimated and true volumes. Volume estimation of stomach and kidneys using 3.25 MHz probe demonstrated limits of agreement of 0.877 to 1.146 and 1.007 to 1.125, respectively, depicting estimated volumes as a proportion of true volumes in 95% of the examinations. Intra- and interobserver variation of the tracing procedure revealed low values. We conclude that this 3D ultrasound system performs high accuracy and precision in volume estimation.

  2. Effect of diltiazem on myocardial infarct size estimated by enzyme release, serial thallium-201 single-photon emission computed tomography and radionuclide angiography

    SciTech Connect

    Zannad, F.; Amor, M.; Karcher, G.; Maurin, P.; Ethevenot, G.; Sebag, C.; Bertrand, A.; Pernot, C.; Gilgenkrantz, J.M.

    1988-06-01

    Diltiazem is a calcium antagonist with demonstrated experimental cardioprotective effects. Its effects on myocardial infarct size were studied in 34 patients admitted within 6 hours after the first symptoms of acute myocardial infarction. These patients were randomized, double-blind to placebo or diltiazem (10-mg intravenous bolus followed by 15 mg/hr intravenous infusion during 72 hours, followed by 4 X 60 mg during 21 days). Myocardial infarct size was assessed by plasma creatine kinase and creatine kinase-MB indexes, perfusion defect scores using single-photon emission computed tomography with thallium-201 and left ventricular ejection fraction measured by radionuclide angiography. Tomographic and angiographic scanning was performed serially before randomization, after 48 hours and 21 days later. Groups were comparable in terms of age, sex, inclusion time and baseline infarct location and size. Results showed no difference in creatine kinase and creatine kinase-MB data between controls and treated patients, a significant decrease in the perfusion defect scores in the diltiazem group (+0.1 +/- 3.0 placebo vs -2.2 +/- 1.9 diltiazem, p less than 0.02) and a better ejection fraction recovery in the diltiazem group (-4.2 +/- 7.4 placebo vs +7.7 +/- 11.2 diltiazem, p less than 0.05). Myocardial infarct size estimates from perfusion defect scores and enzyme data were closely correlated. These preliminary results suggest that diltiazem may reduce ischemic injury in acute myocardial infarction.

  3. Block matching and B-spline methods in deformation estimation in synthetic left ventricular model with nontransmural infarction

    NASA Astrophysics Data System (ADS)

    Żmigrodzki, J.; Cygan, S.; Werys, K.; Leśniak-Plewińska, B.; Kowalski, M.; KałuŻyński, K.

    2017-03-01

    The cardiac elastography aims at identification of non-transmural infarctions. Two displacement estimation methods in such an application using synthetic ultrasonic data are studied. Reference was obtained from Finite Element Modelling. Models had the form of half of an ellipsoid with 15 mm wall thickness. The homogenous model, models with transmural and nontransmural inclusion were designed. Deformation of the models was simulated using Abaqus. Ultrasonic data of LAX and SAX views were generated using Field II. Radial (dR) and lateral (dL) displacements were estimated using a 2D correlation search with 2D stretching (2DCS) and B-spline (BS) method. Strains were estimated using least squares estimator. Mean Absolute Error (MAE) of the dR in the LAX view was approx. 6[μm] for 2DCS and 8[μm] for BS, that of the dL 30 and 24[μm] respectively. MAE of the second component of the principal strain (epsilon)2 was 0.10 and 0.14[%], respectively. Corresponding values for SAX view were 7, 10, 42, 52[μm] and 0.47 and 1.08[%]. In the LAX view both estimation methods result in the (epsilon)2 behavior coherent with the presence of the inclusion, with the 2DCS results closer to the reference. In the SAX view the BS approach results in high errors of the estimate. The (epsilon)2 profiles, LAX view, show minor discrepancies with respect to the reference and show the effect of the inclusion. The (epsilon)2 profiles, SAX view, obtained from displacements estimated using the BS method strongly deviate from the reference. Block matching performs better in application to the local strain estimation.

  4. Collateral flow and brain changes on computed tomography angiography predict infarct volume on early diffusion-weighted imaging.

    PubMed

    Aoki, Junya; Tateishi, Yohei; Cummings, Christopher L; Cheng-Ching, Esteban; Ruggieri, Paul; Hussain, Muhammad Shazam; Uchino, Ken

    2014-01-01

    We investigated whether a computed tomography (CT)-based score could predict a large infarct (≥ 80 mL) on early diffusion-weighted magnetic resonance imaging (DWI). Acute stroke patients considered for endovascular therapy within 8 hours of the onset of symptoms were included. The Alberta Stroke Program Early Computed Tomography Score (ASPECTS) was determined on noncontrast CT and computed tomography angiography source images (CTA-SI). Limited collateral flow was defined as less than 50% collateral filling on CTA-SI. Fifty-six patients were analyzed. National Institutes of Health Stroke Scale score was 20 (15-24) in the large infarct group and 16 (11-20) in the small infarct group (P = .049). ASPECTS on noncontrast CT and CTA-SI was 5 (3-8) and 3 (2-6) in the large infarct group and 9 (8-10) and 8 (7-9) in the small infarct group (both P < .001), respectively. Limited collateral flow was frequent in the large infarct group than in the small infarct group (92% vs. 11%, P < .001). Multivariate analysis found that CTA-SI ASPECTS less than or equal to 5 (odds ratio [OR], 40.55; 95% confidence interval [CI], 1.10-1493.44; P = .044) and limited collateral flow (OR, 114.64; 95% CI, 1.93-6812.79; P = .023) were associated with a large infarct. Absence of ASPECTS less than or equal to 5 and limited collateral flow on CTA-SI predicted absence of a large infarct with a sensitivity of .89, specificity of 1.00, positive predictive value of 1.00, and negative predictive value of .71. Assessment of ASPECTS and collateral flow on CTA-SI may be able to exclude a patient with large infarct on early DWI. Copyright © 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  5. Accuracy of Standing-Tree Volume Estimates Based on McClure Mirror Caliper Measurements

    Treesearch

    Noel D. Cost

    1971-01-01

    The accuracy of standing-tree volume estimates, calculated from diameter measurements taken by a mirror caliper and with sectional aluminum poles for height control, was compared with volume estimates calculated from felled-tree measurements. Twenty-five trees which varied in species, size, and form were used in the test. The results showed that two estimates of total...

  6. Stereological estimation of the orbital volume: a criterion standard study.

    PubMed

    Acer, Niyazi; Sahin, Bünyamin; Ergür, Hayati; Basaloglu, Hulki; Ceri, Nazli Gülriz

    2009-05-01

    Several methodologies have been proposed to assess the orbital volume (OV). However, we have not seen a criterion standard study evaluating the results of the methodologies for the assessment of OV. In the current study, the actual OV of 9 dry skulls was measured using the water filling method as the criterion standard. Consecutive computed tomographic sections at a thickness of 1.5 mm were used to estimate the OV by means of the point counting method. The mean (SD) of the OV measured by the water filling method was 17.84 (1.56) cm3. By using the point counting method, it was 17.05 (1.69) cm3. There was no statistically significant difference between sides (P > 0.001). The results of the OV values obtained by the two methods were compared statistically. The agreements between the two methods were also evaluated using the Bland-Altman plots. There was no statistically significant difference between the OV measurements obtained by the stereological technique and water filling method. The described method could be used for the assessment of OV in vivo.

  7. Performance benchmarking of liver CT image segmentation and volume estimation

    NASA Astrophysics Data System (ADS)

    Xiong, Wei; Zhou, Jiayin; Tian, Qi; Liu, Jimmy J.; Qi, Yingyi; Leow, Wee Kheng; Han, Thazin; Wang, Shih-chang

    2008-03-01

    In recent years more and more computer aided diagnosis (CAD) systems are being used routinely in hospitals. Image-based knowledge discovery plays important roles in many CAD applications, which have great potential to be integrated into the next-generation picture archiving and communication systems (PACS). Robust medical image segmentation tools are essentials for such discovery in many CAD applications. In this paper we present a platform with necessary tools for performance benchmarking for algorithms of liver segmentation and volume estimation used for liver transplantation planning. It includes an abdominal computer tomography (CT) image database (DB), annotation tools, a ground truth DB, and performance measure protocols. The proposed architecture is generic and can be used for other organs and imaging modalities. In the current study, approximately 70 sets of abdominal CT images with normal livers have been collected and a user-friendly annotation tool is developed to generate ground truth data for a variety of organs, including 2D contours of liver, two kidneys, spleen, aorta and spinal canal. Abdominal organ segmentation algorithms using 2D atlases and 3D probabilistic atlases can be evaluated on the platform. Preliminary benchmark results from the liver segmentation algorithms which make use of statistical knowledge extracted from the abdominal CT image DB are also reported. We target to increase the CT scans to about 300 sets in the near future and plan to make the DBs built available to medical imaging research community for performance benchmarking of liver segmentation algorithms.

  8. Comparison of height-accumulation and volume-equation methods for estimating tree and stand volumes. Forest Service research note

    SciTech Connect

    Ferguson, R.B.; Baldwin, V.C.

    1995-09-01

    Estimating tree and stand volume in mature plantations is time consuming, involving much manpower and equipment; however, several sampling and volume-prediction techniques are available. This study showed that a well-constructed, volume-equation method yields estimates comparable to those of the often more time-consuming, hight-accumulation method, even though the latter should be more accurate for any individual tree. Plot volumes were estimated by both methods in a remeasurement of trees in a 40-plot, planted slash pine thinning study. The mean percent age difference in total volume, inside bark, between the two methods ranged from 1 to 2.5 percent across all the plots; differences outside bark ranged from 7 to 10 percent. The results were similar when the effecs of site, plot mean values, or tree-by-tree comparisons were incorporated.

  9. Estimating merchantable volumes of second growth Douglas-fir stands from total cubic volume and associated stand characteristics.

    Treesearch

    Richard L. Williamson; Robert O. Curtis

    1980-01-01

    Equations are given for estimating merchantable volumes of second-growth Douglas-fir stands to specified breast-high and top-diameter limits, in cubic feet or board feet, from total volume in cubic feet and certain associated stand characteristics.

  10. Validation of pre-procedural aortic aneurysm volume calculations to estimate procedural fill volume of endobags in endovascular aortic sealing.

    PubMed

    Boersen, Johannes T; van den Ham, Leo H; Heyligers, Jan M; Vahl, Anco C; Vriens, Patrick W; Reijnen, Michel M; de Vries, Jean-Paul P

    2017-10-01

    Endovascular aortic sealing (EVAS) with a sac anchoring endoprosthesis excludes abdominal aortic aneurysms based on polymer filling of endobags. Primary objective was to assess the reliability of pre-procedural computed tomography (CT) scans based calculations of required endobag volume in relation to intraoperative volume of the endobags. Forty elective EVAS patients were included. Pre-procedural estimations of endobag volume were based on CT segmentations of aortic flow lumen volume, including both automated and manually-adjusted segmentations, performed by two experienced users. Additionally, changes in maximum AAA diameter, thrombus volume and total AAA volume were calculated from pre- and post-procedural CT scans. Automatically determined volumes were comparable to manually-adjusted calculations (75.3 vs. 75.7 mL) and inter-observer agreement regarding pre-EVAS calculations of prefill volume appeared almost perfect with an intra-class correlation coefficient of 0.98 (95% CI: 0.96-0.99). The mean pressure of the endobags was 185 mmHg. Manually-adjusted pre-procedural volume calculations underestimated procedural volume of the endobags (-11.3±9.9 mL). Differences between pre-EVAS and procedural volume measurements were independent from endobag pressure (r=-0.06, P=0.72), prepocedural thrombus volume (r=-0.303, P=0.057) and changes in total AAA volume (r=0.02, P=0.91). A significant association was determined between differences in pre-EVAS and endobag volume versus changes in thrombus volume pre- and post-procedural (r=0.39, P=0.01). In this validation study, pre-procedural volume measurements underestimate the actual fill volume of the endobags. It should be advised to perform a prefill of the endobags during the EVAS procedure.

  11. A non-parametric method for hazard rate estimation in acute myocardial infarction patients: kernel smoothing approach.

    PubMed

    Soltanian, Ali Reza; Hossein, Mahjub

    2012-01-01

    Kernel smoothing method is a non-parametric or graphical method for statistical estimation. In the present study was used a kernel smoothing method for finding the death hazard rates of patients with acute myocardial infarction. By employing non-parametric regression methods, the curve estimation, may have some complexity. In this article, four indices of Epanechnikov, Biquadratic, Triquadratic and Rectangle kernels were used under local and k-nearest neighbors' bandwidth. For comparing the models, were employed mean integrated squared error. To illustrate in the study, was used the dataset of acute myocardial infraction patients in Bushehr port, in the south of Iran. To obtain proper bandwidth, was used generalized cross-validation method. Corresponding to a low bandwidth value, the curve is unreadable and the regression curve is so roughly. In the event of increasing bandwidth value, the distribution has more readable and smooth. In this study, estimate of death hazard rate for the patients based on Epanechnikov kernel under local bandwidth was 1.011 x 10(-11), which had the lowest mean square error compared to k-nearest neighbors bandwidth. We obtained the death hazard rate in 10 and 30 months after the first acute myocardial infraction using Epanechnikov kernelas were 0.0031 and 0.0012, respectively. The Epanechnikov kernel for obtaining death hazard rate of patients with acute myocardial infraction has minimum mean integrated squared error compared to the other kernels. In addition, the mortality hazard rate of acute myocardial infraction in the study was low.

  12. Cumulative Ocean Volume Estimates of the Solar System

    NASA Astrophysics Data System (ADS)

    Frank, E. A.; Mojzsis, S. J.

    2010-12-01

    Although there has been much consideration for habitability in silicate planets and icy bodies, this information has never been quantitatively gathered into a single approximation encompassing our solar system from star to cometary halo. Here we present an estimate for the total habitable volume of the solar system by constraining our definition of habitable environments to those to which terrestrial microbial extremophiles could theoretically be transplanted and yet survive. The documented terrestrial extremophile inventory stretches environmental constraints for habitable temperature and pH space of T ~ -15oC to 121oC and pH ~ 0 to 13.5, salinities >35% NaCl, and gamma radiation doses of 10,000 to 11,000 grays [1]. Pressure is likely not a limiting factor to life [2]. We applied these criteria in our analysis of the geophysical habitable potential of the icy satellites and small icy bodies. Given the broad spectrum of environmental tolerance, we are optimistic that our pessimistic estimates are conservative. Beyond the reaches of our inner solar system's conventional habitable zone (Earth, Mars and perhaps Venus) is Ceres, a dwarf planet in the habitable zone that could possess a significant liquid water ocean if that water contains anti-freezing species [3]. Yet further out, Europa is a small icy satellite that has generated much excitement for astrobiological potential due to its putative subsurface liquid water ocean. It is widely promulgated that the icy moons Enceladus, Triton, Callisto, Ganymede, and Titan likewise have also sustained liquid water oceans. If oceans in Europa, Enceladus, and Triton have direct contact with a rocky mantle hot enough to melt, hydrothermal vents could provide an energy source for chemotrophic organisms. Although oceans in the remaining icy satellites may be wedged between two layers of ice, their potential for life cannot be precluded. Relative to the Jovian style of icy satellites, trans-neptunian objects (TNOs) - icy bodies

  13. Diameter Growth, Survival, and Volume Estimates for Missouri Trees

    Treesearch

    Stephen R. Shifley; W. Brad Smith

    1982-01-01

    Measurements of more than 20,000 Missouri trees were summarized by species and diameter class into tables of mean annual diameter growth, annual probability of survival, net cubic foot volume, and net board foot volume. In the absence of better forecasting techniques, this information can be utilized to project short-term changes for Missouri trees, inventory plots,...

  14. [Effect of ginsenoside Rb1 on cerebral infarction volume and IL-1 beta in the brain tissue and sera of focal cerebral ischemia/reperfusion injury model rats].

    PubMed

    Liu, Jun-Wei; Ren, Ye-Long; Liu, Xu-Ling; Xia, Hong-Lian; Zhang, Hui-Ling; Jin, Shen-Hui; Dai, Qin-Xue; Wang, Jun-Lu

    2013-12-01

    To investigate the effect of ginsenoside Rb1 on cerebral infarction volume as well as IL-1 beta in the brain tissue and sera of focal cerebral ischemia/reperfusion (I/R) injury model rats. The I/R rat model was established by using thread according to Zea-Longa. SD rats were randomly divided into five groups, i.e., the sham-operation group, the model group, the low dose ginsenoside Rb1 (20 mg/kg) group, the medium dose ginsenoside Rb1 group (40 mg/kg), and the high dose ginsenoside Rb1 group (80 mg/kg), 12 in each group. Rats in the sham-operation group only received middle cerebral artery occlusion (MCAO) but without thread insertion. The MCAO model was prepared in the rest 4 groups, followed by MCAO2 h later. Ginsenoside Rb1 at each dose was peritoneally administrated to rats in corresponding groups immediately after cerebral ischemia. Equal volume of normal saline was administered to rats in the sham-operation group. Rats' cerebral infarction volume, integrals of neurologic defect degree, expression of IL-1 beta content in the brain tissue and sera were observed 24 h after 2-h cerebral I/R. In the model group, integrals of neurologic defect degree were improved (P < 0.01), IL-1 beta positive cells in the brain tissue increased and serum IL-1 beta content elevated (P < 0.05), when compared with the sham-operation group. In comparison of the model group, integrals of neurologic defect degree were lowered in the medium dose and high dose ginsenoside Rb1 groups (P < 0.05, P < 0.01). The cerebral infarction volume was all shrunken in each ginsenoside Rb1 group, IL-1 beta positive cells in the brain tissue decreased, and IL-1 beta content in serum reduced (P < 0.01, P < 0.05). Compared with the low dose ginsenoside Rb1 group, integrals of neurologic defect degree decreased, the cerebral infarction volume shrunken, and IL-1 beta content in serum reduced in the high dose ginsenoside Rb1 group (P < 0.01, P < 0.05). Ginsenoside Rb1 (20, 40, 80 mg/kg) might effectively

  15. Modelflow Estimates of Stroke Volume Do Not Correlate With Doppler Ultrasound Estimates During Upright Posture

    NASA Technical Reports Server (NTRS)

    Ferguson, Connor R.; Lee, Stuart M. C.; Stenger, Michael B.; Platts, Steven H.; Laurie, Steven S.

    2014-01-01

    Orthostatic intolerance affects 60-80% of astronauts returning from long-duration missions, representing a significant risk to completing mission-critical tasks. While likely multifactorial, a reduction in stroke volume (SV) represents one factor contributing to orthostatic intolerance during stand and head up tilt (HUT) tests. Current measures of SV during stand or HUT tests use Doppler ultrasound and require a trained operator and specialized equipment, restricting its use in the field. BeatScope (Finapres Medical Systems BV, The Netherlands) uses a modelflow algorithm to estimate SV from continuous blood pressure waveforms in supine subjects; however, evidence supporting the use of Modelflow to estimate SV in subjects completing stand or HUT tests remain scarce. Furthermore, because the blood pressure device is held extended at heart level during HUT tests, but allowed to rest at the side during stand tests, changes in the finger arterial pressure waveform resulting from arm positioning could alter modelflow estimated SV. The purpose of this project was to compare Doppler ultrasound and BeatScope estimations of SV to determine if BeatScope can be used during stand or HUT tests. Finger photoplethysmography was used to acquire arterial pressure waveforms corrected for hydrostatic finger-to-heart height using the Finometer (FM) and Portapres (PP) arterial pressure devices in 10 subjects (5 men and 5 women) during a stand test while simultaneous estimates of SV were collected using Doppler ultrasound. Measures were made after 5 minutes of supine rest and while subjects stood for 5 minutes. Next, SV estimates were reacquired while each arm was independently raised to heart level, a position similar to tilt testing. Supine SV estimates were not significantly different between all three devices (FM: 68+/-20, PP: 71+/-21, US: 73+/-21 ml/beat). Upon standing, the change in SV estimated by FM (-18+/-8 ml) was not different from PP (-21+/-12), but both were significantly

  16. Using GIS to Estimate Lake Volume from Limited Data (Lake and Reservoir Management)

    EPA Science Inventory

    Estimates of lake volume are necessary for calculating residence time and modeling pollutants. Modern GIS methods for calculating lake volume improve upon more dated technologies (e.g. planimeters) and do not require potentially inaccurate assumptions (e.g. volume of a frustum of...

  17. Taper-based system for estimating stem volumes of upland oaks

    Treesearch

    Donald E. Hilt

    1980-01-01

    A taper-based system for estimating stem volumes is developed for Central States upland oaks. Inside bark diameters up the stem are predicted as a function of dbhib, total height, and powers and relative height. A Fortran IV computer program, OAKVOL, is used to predict cubic and board-foot volumes to any desired merchantable top dib. Volumes of...

  18. An upper-bound estimate for the accuracy of volume-area scaling

    NASA Astrophysics Data System (ADS)

    Farinotti, D.; Huss, M.

    2013-06-01

    Volume-area scaling is the most popular method for estimating the ice volume of large glacier samples. Here, a series of resampling experiments based on different sets of synthetic data are presented in order to derive an upper-bound estimate (i.e. a level achieved only with ideal conditions) for the accuracy of its application. We also quantify the maximum accuracy expected when scaling is used for determining the glacier volume change, and area change of a given glacier population. A comprehensive set of measured glacier areas, volumes, area and volume changes is evaluated to investigate the impact of real-world data quality on the so assessed accuracies. For populations larger than a few thousand glaciers, the total ice volume can be recovered within 30% if all measurements available worldwide are used for estimating the scaling coefficients. Assuming no systematic biases in ice volume measurements, their uncertainty is of secondary importance. Knowing the individual areas of a glacier sample for two points in time allows recovering the corresponding ice volume change within 40% for populations larger than a few hundred glaciers, both for steady-state and transient geometries. If ice volume changes can be estimated without bias, glacier area changes derived from volume-area scaling show similar uncertainties as for the volume changes. This paper does not aim at making a final judgement about the suitability of volume-area scaling, but provides the means for assessing the accuracy expected from its application.

  19. Using GIS to Estimate Lake Volume from Limited Data (Lake and Reservoir Management)

    EPA Science Inventory

    Estimates of lake volume are necessary for calculating residence time and modeling pollutants. Modern GIS methods for calculating lake volume improve upon more dated technologies (e.g. planimeters) and do not require potentially inaccurate assumptions (e.g. volume of a frustum of...

  20. A novel method for blood volume estimation using trivalent chromium in rabbit models

    PubMed Central

    Baby, Prathap Moothamadathil; Kumar, Pramod; Kumar, Rajesh; Jacob, Sanu S.; Rawat, Dinesh; Binu, V. S.; Karun, Kalesh M.

    2014-01-01

    Background: Blood volume measurement though important in management of critically ill-patients is not routinely estimated in clinical practice owing to labour intensive, intricate and time consuming nature of existing methods. Aims: The aim was to compare blood volume estimations using trivalent chromium [51Cr(III)] and standard Evans blue dye (EBD) method in New Zealand white rabbit models and establish correction-factor (CF). Materials and Methods: Blood volume estimation in 33 rabbits was carried out using EBD method and concentration determined using spectrophotometric assay followed by blood volume estimation using direct injection of 51Cr(III). Twenty out of 33 rabbits were used to find CF by dividing blood volume estimation using EBD with blood volume estimation using 51Cr(III). CF is validated in 13 rabbits by multiplying it with blood volume estimation values obtained using 51Cr(III). Results: The mean circulating blood volume of 33 rabbits using EBD was 142.02 ± 22.77 ml or 65.76 ± 9.31 ml/kg and using 51Cr(III) was estimated to be 195.66 ± 47.30 ml or 89.81 ± 17.88 ml/kg. The CF was found to be 0.77. The mean blood volume of 13 rabbits measured using EBD was 139.54 ± 27.19 ml or 66.33 ± 8.26 ml/kg and using 51Cr(III) with CF was 152.73 ± 46.25 ml or 71.87 ± 13.81 ml/kg (P = 0.11). Conclusions: The estimation of blood volume using 51Cr(III) was comparable to standard EBD method using CF. With further research in this direction, we envisage human blood volume estimation using 51Cr(III) to find its application in acute clinical settings. PMID:25190922

  1. Deepwater Horizon - Estimating surface oil volume distribution in real time

    NASA Astrophysics Data System (ADS)

    Lehr, B.; Simecek-Beatty, D.; Leifer, I.

    2011-12-01

    Spill responders to the Deepwater Horizon (DWH) oil spill required both the relative spatial distribution and total oil volume of the surface oil. The former was needed on a daily basis to plan and direct local surface recovery and treatment operations. The latter was needed less frequently to provide information for strategic response planning. Unfortunately, the standard spill observation methods were inadequate for an oil spill this size, and new, experimental, methods, were not ready to meet the operational demands of near real-time results. Traditional surface oil estimation tools for large spills include satellite-based sensors to define the spatial extent (but not thickness) of the oil, complemented with trained observers in small aircraft, sometimes supplemented by active or passive remote sensing equipment, to determine surface percent coverage of the 'thick' part of the slick, where the vast majority of the surface oil exists. These tools were also applied to DWH in the early days of the spill but the shear size of the spill prevented synoptic information of the surface slick through the use small aircraft. Also, satellite images of the spill, while large in number, varied considerably in image quality, requiring skilled interpretation of them to identify oil and eliminate false positives. Qualified staff to perform this task were soon in short supply. However, large spills are often events that overcome organizational inertia to the use of new technology. Two prime examples in DWH were the application of hyper-spectral scans from a high-altitude aircraft and more traditional fixed-wing aircraft using multi-spectral scans processed by use of a neural network to determine, respectively, absolute or relative oil thickness. But, with new technology, come new challenges. The hyper-spectral instrument required special viewing conditions that were not present on a daily basis and analysis infrastructure to process the data that was not available at the command

  2. Inference for lidar-assisted estimation of forest growing stock volume

    Treesearch

    Ronald E. McRoberts; Erik Næsset; Terje. Gobakken

    2013-01-01

    Estimates of growing stock volume are reported by the national forest inventories (NFI) of most countries and may serve as the basis for aboveground biomass and carbon estimates as required by an increasing number of international agreements. The probability-based (design-based) statistical estimators traditionally used by NFIs to calculate estimates are generally...

  3. Effects of Measurement Errors on Individual Tree Stem Volume Estimates for the Austrian National Forest Inventory

    Treesearch

    Ambros Berger; Thomas Gschwantner; Ronald E. McRoberts; Klemens. Schadauer

    2014-01-01

    National forest inventories typically estimate individual tree volumes using models that rely on measurements of predictor variables such as tree height and diameter, both of which are subject to measurement error. The aim of this study was to quantify the impacts of these measurement errors on the uncertainty of the model-based tree stem volume estimates. The impacts...

  4. Critical length sampling: a method to estimate the volume of downed coarse woody debris

    Treesearch

    G& #246; ran St& #229; hl; Jeffrey H. Gove; Michael S. Williams; Mark J. Ducey

    2010-01-01

    In this paper, critical length sampling for estimating the volume of downed coarse woody debris is presented. Using this method, the volume of downed wood in a stand can be estimated by summing the critical lengths of down logs included in a sample obtained using a relascope or wedge prism; typically, the instrument should be tilted 90° from its usual...

  5. Estimating volume, biomass, and potential emissions of hand-piled fuels

    Treesearch

    Clinton S. Wright; Cameron S. Balog; Jeffrey W. Kelly

    2009-01-01

    Dimensions, volume, and biomass were measured for 121 hand-constructed piles composed primarily of coniferous (n = 63) and shrub/hardwood (n = 58) material at sites in Washington and California. Equations using pile dimensions, shape, and type allow users to accurately estimate the biomass of hand piles. Equations for estimating true pile volume from simple geometric...

  6. Guidelines for estimating volume, biomass, and smoke production for piled slash. Forest Service general technical report

    SciTech Connect

    Hardy, C.C.

    1996-02-01

    Guidelines in the form of a six-step approach are provided for estimating volumes, oven-dry mass, consumption, and particulate matter emissions for piled logging debris. Seven stylized pile shapes and their associated geometric volume formulae are used to estimate gross pile volumes. The gross volumes are then reduced to net wood volume by applying an appropriate wood-to-pile volume packing ratio. Next, the oven-dry mass of the pile is determined by using the wood density, or a weighted-average of two wood densitities, for any of 14 tree species commonly piled and burned in the Western United States. Finally, the percentage of biomass consumed is multiplied by an appropriate emission factor to determine the mass of PM, PM10, and PM2.5 produced from the burned pile. These estimates can be extended to represent multiple piles, or multiple groups of similar piles, to estimate the particulate emissions from an entire burn project.

  7. An experimental result of estimating an application volume by machine learning techniques.

    PubMed

    Hasegawa, Tatsuhito; Koshino, Makoto; Kimura, Haruhiko

    2015-01-01

    In this study, we improved the usability of smartphones by automating a user's operations. We developed an intelligent system using machine learning techniques that periodically detects a user's context on a smartphone. We selected the Android operating system because it has the largest market share and highest flexibility of its development environment. In this paper, we describe an application that automatically adjusts application volume. Adjusting the volume can be easily forgotten because users need to push the volume buttons to alter the volume depending on the given situation. Therefore, we developed an application that automatically adjusts the volume based on learned user settings. Application volume can be set differently from ringtone volume on Android devices, and these volume settings are associated with each specific application including games. Our application records a user's location, the volume setting, the foreground application name and other such attributes as learning data, thereby estimating whether the volume should be adjusted using machine learning techniques via Weka.

  8. A method of estimating cubic volume in felled trees

    Treesearch

    Frederick E. Hampf; C. Allen Bickford

    1959-01-01

    This paper describes a new method of computing the gross volume of felled trees or sections of trees. The method has many applications, but most are limited to forest research and management, especially in making surveys.

  9. Palatine tonsil volume estimation using different methods after tonsillectomy.

    PubMed

    Sağıroğlu, Ayşe; Acer, Niyazi; Okuducu, Hacı; Ertekin, Tolga; Erkan, Mustafa; Durmaz, Esra; Aydın, Mesut; Yılmaz, Seher; Zararsız, Gökmen

    2016-06-15

    This study was carried out to measure the volume of the palatine tonsil in otorhinolaryngology outpatients with complaints of adenotonsillar hypertrophy and chronic tonsillitis who had undergone tonsillectomy. To date, no study has investigated palatine tonsil volume using different methods and compared with subjective tonsil size in the literature. For this purpose, we used three different methods to measure palatine tonsil volume. The correlation of each parameter with tonsil size was assessed. After tonsillectomy, palatine tonsil volume was measured by Archimedes, Cavalieri and Ellipsoid methods. Mean right-left palatine tonsil volumes were calculated as 2.63 ± 1.34 cm(3) and 2.72 ± 1.51 cm(3) by the Archimedes method, 3.51 ± 1.48 cm(3) and 3.37 ± 1.36 cm(3) by the Cavalieri method, and 2.22 ± 1.22 cm(3) and 2.29 ± 1.42 cm(3) by the Ellipsoid method, respectively. Excellent agreement was found among the three methods of measuring volumetric techniques according to Bland-Altman plots. In addition, tonsil grade was correlated significantly with tonsil volume.

  10. Estimate or calculate? How surgeons rate volumes and surfaces.

    PubMed

    Schuld, Jochen; Kollmar, Otto; Seidel, Roland; Black, Catherine; Schilling, Martin K; Richter, Sven

    2012-06-01

    Surgeons frequently describe the shape of intraoperative findings using visual judgement and their own sense of proportion or describing these findings in comparison to commonly used or metaphoric subjects. The aim of the study was to analyse the reliability of surgeon's estimations of dimensions. The study was performed in two phases. First, physicians had to estimate the metric proportions of four well-known objects. Second, surgeons were asked intraoperatively to estimate the liver resection surface after partial hepatectomy. The exact surface of the resection plane was measured using computed tomography-guided planimetry of the resection specimen. Physician's estimations and the exact measurements of the well-known objects and the liver resection surface were compared. Systematic error was defined by the natural logarithm of estimated/real size. We found a large individual discrepancy in estimating the metric proportions of commonly used objects and a tendency to underestimate both commonly used objects and liver resection surface. Experienced liver surgeons were more accurate in estimating liver resection surface compared with younger staff members. We found a large bias in estimating the dimension of both commonly used objects and the surface area of liver parenchyma transection. Obviously, estimating errors are more influenced by the individual subject who estimates than by the object itself. In clinical routine, surgeons should rely more on simple measuring devices than on their own sense of proportion. Education in how to estimate more correctly human liver resection surfaces can be achieved by ex vivo studies using porcine livers.

  11. Unbiased volume estimation with coaxial sections: an application to the human bladder.

    PubMed

    Cruz-Orive, L M; Roberts, N

    1993-04-01

    A problem of current medical interest is how to estimate the volume of an object from coaxial sections. Such images can be produced in ultrasound scanning, when the planar scan sections all emanate from a common axis. Two unbiased volume estimators for this sampling regime, previously published without derivation, are derived and presented here in some detail. The estimators are based on an ancient theorem of Pappus of Alexandria (c. AD 320). One of the estimators was used to estimate the volume of urine in the bladder of six human volunteers. The case example was attractive because the corresponding volumes could be voided and directly measured after the scanning session, thus confirming the unbiasedness of the estimator used. Sample size guidelines are also given.

  12. Modeled estimates of myocardial infarction and venous thromboembolic disease in users of second and third generation oral contraceptives.

    PubMed

    Schwingl, P J; Shelton, J

    1997-03-01

    Consistent reports from several recent studies suggest that users of third generation oral contraceptives (OCs) containing gestodene and desogestrel may be at increased risk of venous thromboembolic disease (VTE). Paradoxically, other reports indicate that these users may be at decreased risk of acute myocardial infarction (MI) compared with users of second generation OCs. To determine whether the potentially increased risk of VTE would outweigh the potentially reduced risk of MI in users of third generation OCs, we conducted an analysis to quantify the trade-offs providers and users may be faced to make between these formulations. The baseline rates of VTE and MI among non-users were calculated using US data on incidence and mortality of these conditions and estimates of the proportion of women exposed to these formulations in the US. These were multiplied by relative risks published in recent studies on third generation progestins to produce age- and formulation-specific risks. Results indicate that there would be small differences in disease burden between users of second and third generation OCs under the model assumptions at younger ages. However, among women 35-44 years of age, modeling results indicate that the potentially decreased incidence of MI among users of third generation OCs more than offsets the potentially increased risk of VTE at this age.

  13. Estimating Lost Volumes in a University Library Collection

    ERIC Educational Resources Information Center

    Niland, Powell; Kurth, William

    1976-01-01

    This study employed standard sampling theory to make a study of library book losses, but unlike previously reported studies, the investigators instituted periodic searches for volumes missing after the original search. Over a period of two years and nine months, the original figures were cut by more than 60 percent. (Author)

  14. System Development of Estimated Figures of Volume Production Plan

    ERIC Educational Resources Information Center

    Brazhnikov, Maksim A.; Khorina, Irina V.; Minina, Yulia I.; Kolyasnikova, Lyudmila V.; Streltsov, Aleksey V.

    2016-01-01

    The relevance of this problem is primarily determined by a necessity of improving production efficiency in conditions of innovative development of the economy and implementation of Import Substitution Program. The purpose of the article is development of set of criteria and procedures for the comparative assessment of alternative volume production…

  15. Tree form quotients as variables in volume estimation.

    Treesearch

    Gerald E. Hoyer

    1985-01-01

    The study reviews Hohenadl's procedure for defining form quotients and tree volume from diameters measured at fixed proportions of total tree height. Modifications of Hohenadl's procedure were applied to two sets of data for western hemlock (Tsuga heterophylla (Raf.) Sarg.) from the Pacific Northwest. The procedure was used to define...

  16. Glacier volume estimation of Cascade Volcanoes—an analysis and comparison with other methods

    USGS Publications Warehouse

    Driedger, Carolyn L.; Kennard, P.M.

    1986-01-01

    During the 1980 eruption of Mount St. Helens, the occurrence of floods and mudflows made apparent a need to assess mudflow hazards on other Cascade volcanoes. A basic requirement for such analysis is information about the volume and distribution of snow and ice on these volcanoes. An analysis was made of the volume-estimation methods developed by previous authors and a volume estimation method was developed for use in the Cascade Range. A radio echo-sounder, carried in a backpack, was used to make point measurements of ice thickness on major glaciers of four Cascade volcanoes (Mount Rainier, Washington; Mount Hood and the Three Sisters, Oregon; and Mount Shasta, California). These data were used to generate ice-thickness maps and bedrock topographic maps for developing and testing volume-estimation methods. Subsequently, the methods were applied to the unmeasured glaciers on those mountains and, as a test of the geographical extent of applicability, to glaciers beyond the Cascades having measured volumes. Two empirical relationships were required in order to predict volumes for all the glaciers. Generally, for glaciers less than 2.6 km in length, volume was found to be estimated best by using glacier area, raised to a power. For longer glaciers, volume was found to be estimated best by using a power law relationship, including slope and shear stress. The necessary variables can be estimated from topographic maps and aerial photographs.

  17. Comparison Between Multicopter Uav and Total Station for Estimating Stockpile Volumes

    NASA Astrophysics Data System (ADS)

    Arango, C.; Morales, C. A.

    2015-08-01

    Currently the UAV (Unmanned Aerial Vehicle) have become an alternative for different engineering applications, especially in surveying, one of these applications is the calculation of volumes of stockpiled material, but there are questions about its accuracy and efficiency, the purpose of this article is to compare traditional surveying methods for estimating total volumes through data obtained by total stations and data obtained by a multicopter UAV. In order to answer these questions we obtain data from the same location and the results were compared. After comparing the results it was found that there was a 2,88% difference between the volume calculated with the total station data and the actual volume, and -0,67% difference between the volume calculated with the UAV data and the actual volume, concluding that the estimated volume with UAV data is more accurate.

  18. Preoperative TRAM free flap volume estimation for breast reconstruction in lean patients.

    PubMed

    Minn, Kyung Won; Hong, Ki Yong; Lee, Sang Woo

    2010-04-01

    To obtain pleasing symmetry in breast reconstruction with transverse rectus abdominis myocutaneous (TRAM) free flap, a large amount of abdominal flap is elevated and remnant tissue is trimmed in most cases. However, elevation of abundant abdominal flap can cause excessive tension in donor site closure and increase the possibility of hypertrophic scarring especially in lean patients. The TRAM flap was divided into 4 zones in routine manner; the depth and dimension of the 4 zones were obtained using ultrasound and AutoCAD (Autodesk Inc., San Rafael, CA), respectively. The acquired numbers were then multiplied to obtain an estimate of volume of each zone and the each zone volume was added. To confirm the relation between the estimated volume and the actual volume, authors compared intraoperative actual TRAM flap volumes with preoperative estimated volumes in 30 consecutive TRAM free flap breast reconstructions. The estimated volumes and the actual elevated volumes of flap were found to be correlated by regression analysis (r = 0.9258, P < 0.01). According to this result, we could confirm the reliability of the preoperative volume estimation using our method. Afterward, the authors applied this method to 7 lean patients by estimation and revision of the design and obtained symmetric results with minimal donor site morbidity. Preoperative estimation of TRAM flap volume with ultrasound and AutoCAD (Autodesk Inc.) allow the authors to attain the precise volume desired for elevation. This method provides advantages in terms of minimal flap trimming, easier closure of donor sites, reduced scar widening and symmetry, especially in lean patients.

  19. Temporary vessel occlusion in spontaneously hypertensive and normotensive rats. Effect of single and multiple episodes on tissue metabolism and volume of infarction.

    PubMed

    Selman, W R; Bhatti, S U; Rosenstein, C C; Lust, W D; Ratcheson, R A

    1994-06-01

    Temporary occlusion of an intracranial artery is frequently necessary in the surgical management of intracranial aneurysms, arteriovenous malformations, and tumors. While the risks of vessel damage associated with clip application have been lessened by improved design, the threat of ischemic damage remains. It is unclear whether multiple, brief periods of clip application are more or less safe than a single period of occlusion, and whether the underlying cerebrovascular status influences the outcome from either method. The effect of each of these paradigms (single: 1-hour occlusion; multiple: three 20-minute episodes separated by 10 minutes of reperfusion) on histopathological outcome was assessed in a middle cerebral artery (MCA) occlusion model using both normotensive and spontaneously hypertensive rats. The mean volume of infarction (+/- standard error of the mean) was not different between the single-ischemic (49.4 +/- 17.3 cu mm) and the multiple-ischemic (42.9 +/- 12.9 cu mm) episode groups of normotensive rats, whereas in the spontaneously hypertensive rats a significant difference existed between the volume of infarction for the single-occlusion group (126.7 +/- 18.7 cu mm) and the multiple-occlusion group (162.4 +/- 15.5 cu mm) (p < 0.05). The metabolic data obtained from spontaneously hypertensive animals did not provide an explanation for the larger infarction in that there were no significant differences between the single- and multiple-occlusion groups with respect to tissue glucose, adenosine triphosphate, or lactate levels. The results suggest that intermittent reperfusion may have different effects depending not only on the degree and duration of ischemia and reperfusion, but also on the underlying cerebrovascular status.

  20. Rosiglitazone, a peroxisome proliferator-activated receptor-gamma ligand, reduces infarction volume and neurological deficits in an embolic model of stroke.

    PubMed

    Allahtavakoli, Mohammad; Shabanzadeh, Alireza P; Sadr, Seyed Shahabeddin; Parviz, Mohsen; Djahanguiri, Bijan

    2006-11-01

    1. Stroke is accompanied by a robust inflammatory response, glutamate-mediated excitotoxicity, release of reactive oxygen species and apoptosis. Thiazolidinediones, which target the nuclear receptor peroxisome proliferator-activated receptor (PPAR)-g, have been reported recently to exhibit potent anti-inflammatory and anti-oxidant actions and inhibit both neural excitotoxicity and apoptosis. 2. The present study was conducted to determine whether rosiglitazone, a potent thiazolidinedione for PPAR-g, would show efficacy against the cerebral infarction and neurological dysfunctions induced by embolic middle cerebral artery (MCA) occlusion in the rat. 3. Focal ischaemic injury was induced by embolizing a preformed clot into the MCA. Rosiglitazone was dissolved in dimethyl sulphoxide and injected i.p. 1 h before MCA occlusion at doses of 0.33, 0.1, 0.3 or 1 mg/kg. In addition, 1 mg/kg rosiglitazone was used immediately or 4 h after embolization. Forty-eight hours after MCA occlusion, brains were removed, sectioned and stained with a 2% solution of 2,3,5-triphenyltetrazolum chloride and analysed using a commercial image-processing software program. 4. When rosiglitazone was administered 1 h before embolization, it significantly reduced infarct volume by 48.2, 68.4% and 70.3% at doses of 0.1, 0.3 and 1 mg/kg, respectively (P < 0.001). Administration of rosiglitazone (1 mg/kg) immediately or 4 h after stroke also reduced infarct volume by 67 and 50.8%, respectively (P < 0.001). Rosiglitazone-treated rats also demonstrated improved neurological functions. However, there were no statistically significant differences between control and treated groups in terms of brain oedema at 48 h after ischaemic injury. 5. The findings of the present study may support the idea of a potential benefit of thiazolidinediones in the management of ischaemic stroke.

  1. Space shuttle propulsion estimation development verification, volume 1

    NASA Technical Reports Server (NTRS)

    Rogers, Robert M.

    1989-01-01

    The results of the Propulsion Estimation Development Verification are summarized. A computer program developed under a previous contract (NAS8-35324) was modified to include improved models for the Solid Rocket Booster (SRB) internal ballistics, the Space Shuttle Main Engine (SSME) power coefficient model, the vehicle dynamics using quaternions, and an improved Kalman filter algorithm based on the U-D factorized algorithm. As additional output, the estimated propulsion performances, for each device are computed with the associated 1-sigma bounds. The outputs of the estimation program are provided in graphical plots. An additional effort was expended to examine the use of the estimation approach to evaluate single engine test data. In addition to the propulsion estimation program PFILTER, a program was developed to produce a best estimate of trajectory (BET). The program LFILTER, also uses the U-D factorized algorithm form of the Kalman filter as in the propulsion estimation program PFILTER. The necessary definitions and equations explaining the Kalman filtering approach for the PFILTER program, the models used for this application for dynamics and measurements, program description, and program operation are presented.

  2. Estimating load weights with Huber's Cubic Volume formula: a field trial.

    Treesearch

    Dale R. Waddell

    1989-01-01

    Log weights were estimated from the product of Huber's cubic volume formula and green density. Tags showing estimated log weights were attached to logs in the field, and the weights were tallied into a single load weight as logs were assembled for aerial yarding. Accuracy of the estimated load weights was evaluated by comparing the predicted with the actual load...

  3. Post-stratified estimation of forest area and growing stock volume using lidar-based stratifications

    Treesearch

    Ronald E. McRoberts; Terje Gobakken; Erik. Næsset

    2012-01-01

    National forest inventories report estimates of parameters related to forest area and growing stock volume for geographic areas ranging in size from municipalities to entire countries. Landsat imagery has been shown to be a source of auxiliary information that can be used with stratified estimation to increase the precision of estimates, although the increase is...

  4. A method of estimating flood volumes in western Kansas

    USGS Publications Warehouse

    Perry, C.A.

    1984-01-01

    Relationships between flood volume and peak discharge in western Kansas were developed considering basin and climatic characteristics in order to evaluate the availability of surface water in the area. Multiple-regression analyses revealed a relationship between flood volume, peak discharge, channel slope , and storm duration for basins smaller than 1,503 square miles. The equation VOL=0.536 PEAK1.71 SLOPE-0.85 DUR0.24, had a correlation coefficient of R=0.94 and a standard error of 0.33 log units (-53 and +113 percent). A better relationship for basins smaller than 228 square miles resulted in the equation VOL=0.483 PEAK0.98 SLOPE-0.74 AREA0.30, which had a correlation coefficient of R=0.90 and a standard error of 0.23 log units (-41 and +70 percent). (USGS)

  5. Estimates of the volume of water in five coal aquifers, Northern Cheyenne Indian Reservation, southeastern Montana

    USGS Publications Warehouse

    Tuck, L.K.; Pearson, Daniel K.; Cannon, M.R.; Dutton, DeAnn M.

    2013-01-01

    The Tongue River Member of the Tertiary Fort Union Formation is the primary source of groundwater in the Northern Cheyenne Indian Reservation in southeastern Montana. Coal beds within this formation generally contain the most laterally extensive aquifers in much of the reservation. The U.S. Geological Survey, in cooperation with the Northern Cheyenne Tribe, conducted a study to estimate the volume of water in five coal aquifers. This report presents estimates of the volume of water in five coal aquifers in the eastern and southern parts of the Northern Cheyenne Indian Reservation: the Canyon, Wall, Pawnee, Knobloch, and Flowers-Goodale coal beds in the Tongue River Member of the Tertiary Fort Union Formation. Only conservative estimates of the volume of water in these coal aquifers are presented. The volume of water in the Canyon coal was estimated to range from about 10,400 acre-feet (75 percent saturated) to 3,450 acre-feet (25 percent saturated). The volume of water in the Wall coal was estimated to range from about 14,200 acre-feet (100 percent saturated) to 3,560 acre-feet (25 percent saturated). The volume of water in the Pawnee coal was estimated to range from about 9,440 acre-feet (100 percent saturated) to 2,360 acre-feet (25 percent saturated). The volume of water in the Knobloch coal was estimated to range from about 38,700 acre-feet (100 percent saturated) to 9,680 acre-feet (25 percent saturated). The volume of water in the Flowers-Goodale coal was estimated to be about 35,800 acre-feet (100 percent saturated). Sufficient data are needed to accurately characterize coal-bed horizontal and vertical variability, which is highly complex both locally and regionally. Where data points are widely spaced, the reliability of estimates of the volume of coal beds is decreased. Additionally, reliable estimates of the volume of water in coal aquifers depend heavily on data about water levels and data about coal-aquifer characteristics. Because the data needed to

  6. Historical volume estimation and a structured method for calculating habitable volume for in-space and surface habitats

    NASA Astrophysics Data System (ADS)

    Simon, M.; Bobskill, M. R.; Wilhite, A.

    2012-11-01

    Habitable volume is an important spacecraft design figure of merit necessary to determine the required size of crewed space vehicles, or habitats. In order to design habitats for future missions and properly compare the habitable volumes of future habitat designs with historical spacecraft, consistent methods of both defining the required amount of habitable volume and estimating the habitable volume for a given layout are required. This paper provides a brief summary of historical habitable volume requirements and describes the appropriate application of requirements to various types of missions, particularly highlighting the appropriate application for various gravity environments. Then the proposed "Marching Grid Method", a structured automatic, numerical method to calculate habitable volume for a given habitat design, is described in detail. This method uses a set of geometric Boolean tests applied to a discrete set of points within the pressurized volume to numerically estimate the functionally usable and accessible space that comprises the habitable volume. The application of this method to zero gravity and nonzero gravity environments is also discussed. This proposed method is then demonstrated by calculating habitable volumes using two conceptual-level layouts of habitat designs, one for each type of gravity environment. These include the US Laboratory Module on ISS and the Scenario 12.0 Pressurized Core Module from the recent NASA Lunar Surface Systems studies. Results of this study include a description of the effectiveness of this method for various resolutions of the investigated grid, and commentary highlighting the use of this method to determine the overall utility of interior configurations for automatically evaluating interior layouts.

  7. Prostate volume estimations using magnetic resonance imaging and transrectal ultrasound compared to radical prostatectomy specimens

    PubMed Central

    Paterson, Nicholas R.; Lavallée, Luke T.; Nguyen, Laura N.; Witiuk, Kelsey; Ross, James; Mallick, Ranjeeta; Shabana, Wael; MacDonald, Blair; Scheida, Nicola; Fergusson, Dean; Momoli, Franco; Cnossen, Sonya; Morash, Christopher; Cagiannos, Ilias; Breau, Rodney H.

    2016-01-01

    Introduction: We sought to evaluate the accuracy of prostate volume estimates in patients who received both a preoperative transrectal ultrasound (TRUS) and magnetic resonance imaging (MRI) in relation to the referent pathological specimen post-radical prostatectomy. Methods: Patients receiving both TRUS and MRI prior to radical prostatectomy at one academic institution were retrospectively analyzed. TRUS and MRI volumes were estimated using the prolate ellipsoid formula. TRUS volumes were collected from sonography reports. MRI volumes were estimated by two blinded raters and the mean of the two was used for analyses. Pathological volume was calculated using a standard fluid displacement method. Results: Three hundred and eighteen (318) patients were included in the analysis. MRI was slightly more accurate than TRUS based on interclass correlation (0.83 vs. 0.74) and absolute risk bias (higher proportion of estimates within 5, 10, and 20 cc of pathological volume). For TRUS, 87 of 298 (29.2%) prostates without median lobes differed by >10 cc of specimen volume and 22 of 298 (7.4%) differed by >20 cc. For MRI, 68 of 298 (22.8%) prostates without median lobes differed by >10 cc of specimen volume, while only 4 of 298 (1.3%) differed by >20 cc. Conclusions: MRI and TRUS prostate volume estimates are consistent with pathological volumes along the prostate size spectrum. MRI demonstrated better correlation with prostatectomy specimen volume in most patients and may be better suited in cases where TRUS and MRI estimates are disparate. Validation of these findings with prospective, standardized ultrasound techniques would be helpful. PMID:27878049

  8. Cardiologist service volume, percutaneous coronary intervention and hospital level in relation to medical costs and mortality in patients with acute myocardial infarction: a nationwide study.

    PubMed

    Liu, C-Y; Lin, Y-N; Lin, C-L; Chang, Y-J; Hsu, Y-H; Tsai, W-C; Kao, C-H

    2014-07-01

    We explore whether cardiologist service volume, hospital level and percutaneous coronary intervention (PCI) are associated with medical costs and acute myocardial infarction (AMI) mortality. From the 1997-2010 Taiwan National Health Insurance Research Database of the National Health Research Institute, we identified AMI patients and performed multiple regression analyses to explore the relationships among the different hospital levels and treatment factors. We identified 2942 patients with AMI in medical centers and 4325 patients with AMI in regional hospitals. Cardiologist service volume, performing PCI and medical costs per patient were higher in medical centers than in regional hospitals (P < 0.0001). However, the two hospital levels did not differ significantly in in-hospital mortality (P = 0.1557). Post hoc analysis showed significant differences in in-hospital mortality rate and in medical costs among the eight groups subdivided on the basis of hospital level, cardiologist service volume, and whether PCI was performed (P < 0.001 and P = 0.001, respectively). These results highlight the importance of encouraging hospitals to develop PCI capability and increase their cardiologist service volume after taking medical costs into account. Transferring AMI patients to hospitals with higher cardiologist service volume and PCI performed can also be very important. © The Author 2014. Published by Oxford University Press on behalf of the Association of Physicians. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Perfusion-weighted imaging and dynamic 4D angiograms for the estimation of collateral blood flow in lacunar infarction.

    PubMed

    Förster, Alex; Mürle, Bettina; Böhme, Johannes; Al-Zghloul, Mansour; Kerl, Hans U; Wenz, Holger; Groden, Christoph

    2016-10-01

    Although lacunar infarction accounts for approximately 25% of ischemic strokes, collateral blood flow through anastomoses is not well evaluated in lacunar infarction. In 111 lacunar infarction patients, we analyzed diffusion-weighted images, perfusion-weighted images, and blood flow on dynamic four-dimensional angiograms generated by use of Signal Processing In NMR-Software. Blood flow was classified as absent (type 1), from periphery to center (type 2), from center to periphery (type 3), and combination of type 2 and 3 (type 4). On diffusion-weighted images, lacunar infarction was found in the basal ganglia (11.7%), internal capsule (24.3%), corona radiata (30.6%), thalamus (24.3%), and brainstem (9.0%). In 58 (52.2%) patients, perfusion-weighted image showed a circumscribed hypoperfusion, in one (0.9%) a circumscribed hyperperfusion, whereas the remainder was normal. In 36 (62.1%) patients, a larger perfusion deficit (>7 mm) was observed. In these, blood flow was classified type 1 in four (11.1%), 2 in 17 (47.2%), 3 in 9 (25.0%), and 4 in six (16.7%) patients. Patients with lacunar infarction in the posterior circulation more often demonstrated blood flow type 2 and less often type 3 (p = 0.01). Detailed examination and graduation of blood flow in lacunar infarction by use of dynamic four-dimensional angiograms is feasible and may serve for a better characterization of this stroke subtype.

  10. Space Station Furnace Facility. Volume 3: Program cost estimate

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The approach used to estimate costs for the Space Station Furnace Facility (SSFF) is based on a computer program developed internally at Teledyne Brown Engineering (TBE). The program produces time-phased estimates of cost elements for each hardware component, based on experience with similar components. Engineering estimates of the degree of similarity or difference between the current project and the historical data is then used to adjust the computer-produced cost estimate and to fit it to the current project Work Breakdown Structure (WBS). The SSFF Concept as presented at the Requirements Definition Review (RDR) was used as the base configuration for the cost estimate. This program incorporates data on costs of previous projects and the allocation of those costs to the components of one of three, time-phased, generic WBS's. Input consists of a list of similar components for which cost data exist, number of interfaces with their type and complexity, identification of the extent to which previous designs are applicable, and programmatic data concerning schedules and miscellaneous data (travel, off-site assignments). Output is program cost in labor hours and material dollars, for each component, broken down by generic WBS task and program schedule phase.

  11. Estimating the rock volume bias in paleobiodiversity studies.

    PubMed

    Crampton, James S; Beu, Alan G; Cooper, Roger A; Jones, Craig M; Marshall, Bruce; Maxwell, Phillip A

    2003-07-18

    To interpret changes in biodiversity through geological time, it is necessary first to correct for biases in sampling effort related to variations in the exposure of rocks and recovery of fossils with age. Data from New Zealand indicate that outcrop area is likely to be a reliable proxy of rock volume in both stable cratonic regions, where the paleobiodiversity record is strongly correlated with relative sea level, and on tectonically active margins. In contrast, another potential proxy, the number of rock formations, is a poor predictor of outcrop area or sampling effort in the New Zealand case.

  12. In search of physiologically based distribution volume estimates for macromolecules.

    PubMed

    Garzone, P D; Atkinson, A J

    2012-10-01

    In their semimechanistic analysis of trastuzumab emtansine (T-DM1) pharmacokinetics, Chudasama et al., as reported in this issue, modeled the process of T-DM1 deconjugation with a series of transit compartments representing plasma volume and a single peripheral compartment. The implausibility of the two-compartment distribution model used in this study as well as in other recent attempts to analyze the distribution kinetics of trastuzumab and other macromolecules reflects the fact that this modeling has been guided primarily by statistical rather than physiological considerations.

  13. Space tug economic analysis study. Volume 3: Cost estimates

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Cost estimates for the space tug operation are presented. The subjects discussed are: (1) research and development costs, (2) investment costs, (3) operations costs, and (4) funding requirements. The emphasis is placed on the single stage tug configuration using various types of liquid propellants.

  14. Assessments of wildlife viability, old-growth timber volume estimates, forested wetlands, and slope stability.

    Treesearch

    Kent R. Julin

    1997-01-01

    Resource assessments on wildlife viability, old-growth timber volume estimates, forested wetlands, and slope stability are presented. These assessments were used in the formulation of alternatives in the revision of the Tongass land management plan.

  15. Cardiac output assessment using oxygen consumption estimated from the left ventricular pressure-volume area.

    PubMed

    Negroni, Jorge A; Lascano, Elena C; Bertolotti, Alejandro M; Gómez, Carmen B; Rodríguez Correa, Carlos A; Favaloro, Roberto R

    2010-01-01

    Use of a majority of structural variables (age, sex, height) to estimate oxygen consumption in the calculation of cardiac output (CO) by the Fick principle does not account for changes in physiological conditions. To improve this limitation, oxygen consumption was estimated based on the left ventricular pressure-volume area. A pilot study with 10 patients undergoing right cardiac catheterization showed that this approach was successful to estimate CO (r=0,73, vs. thermodilution measured CO). Further essays changing end-diastolic-volume in the pressure-volume area formula by body weight or body surface area showed that this last yielded the best correlation with the thermodilution measured CO (slope=1, ordinate =0.01 and r=0.93). These preliminary results indicate that use of a formula originated from the pressure-volume-area concept is a good alternative to estimate oxygen consumption for CO calculation.

  16. An upper-bound estimate for the accuracy of glacier volume-area scaling

    NASA Astrophysics Data System (ADS)

    Farinotti, D.; Huss, M.

    2013-11-01

    Volume-area scaling is the most popular method for estimating the ice volume of large glacier samples. Here, a series of resampling experiments based on different sets of synthetic data is presented in order to derive an upper-bound estimate (i.e. a level achieved only within ideal conditions) for its accuracy. For real-world applications, a lower accuracy has to be expected. We also quantify the maximum accuracy expected when scaling is used for determining the glacier volume change, and area change of a given glacier population. A comprehensive set of measured glacier areas, volumes, area and volume changes is evaluated to investigate the impact of real-world data quality on the so-assessed accuracies. For populations larger than a few thousand glaciers, the total ice volume can be recovered within 30% if all data currently available worldwide are used for estimating the scaling parameters. Assuming no systematic bias in ice volume measurements, their uncertainty is of secondary importance. Knowing the individual areas of a glacier sample for two points in time allows recovering the corresponding ice volume change within 40% for populations larger than a few hundred glaciers, both for steady-state and transient geometries. If ice volume changes can be estimated without bias, glacier area changes derived from volume-area scaling show similar uncertainties to those of the volume changes. This paper does not aim at making a final judgement on the suitability of volume-area scaling as such, but provides the means for assessing the accuracy expected from its application.

  17. Estimation of Surface Area and Volume of a Nematode from Morphometric Data

    PubMed Central

    Brown, Simon; Pedley, Kevin C.; Simcock, David C.

    2016-01-01

    Nematode volume and surface area are usually based on the inappropriate assumption that the animal is cylindrical. While nematodes are approximately circular in cross section, the radius varies longitudinally. We use standard morphometric data to obtain improved estimates of volume and surface area based on (i) a geometrical approach and (ii) a Bézier representation of the nematode. These new estimators require only the morphometric data available from Cobb's ratios, but if fewer coordinates are available the geometric approach reduces to the standard estimates. Consequently, these new estimators are better than the standard alternatives. PMID:27110427

  18. Market projections of cellulose nanomaterial-enabled products-- Part 2: Volume estimates

    Treesearch

    John Cowie; E.M. (Ted) Bilek; Theodore H. Wegner; Jo Anne Shatkin

    2014-01-01

    Nanocellulose has enormous potential to provide an important materials platform in numerous product sectors. This study builds on previous work by the same authors in which likely high-volume, low-volume, and novel applications for cellulosic nanomaterials were identified. In particular, this study creates a transparent methodology and estimates the potential annual...

  19. Timber volume and aboveground live tree biomass estimations for landscape analyses in the Pacific Northwest

    Treesearch

    Xiaoping Zhou; Miles A. Hemstrom

    2010-01-01

    Timber availability, aboveground tree biomass, and changes in aboveground carbon pools are important consequences of landscape management. There are several models available for calculating tree volume and aboveground tree biomass pools. This paper documents species-specific regional equations for tree volume and aboveground live tree biomass estimation that might be...

  20. Complex compatible taper and volume estimation systems for red and loblolly pine

    Treesearch

    John C. Byrne; David D. Reed

    1986-01-01

    Five equation systems are described which can be used to estimate upper stem diameter, total individual tree cubic-foot volume, and merchantable cubic-foot volumes to any merchantability imit (expressed in terms of diameter or height), both inside and outside bark. The equations provide consistent results since they are mathematically related and are fit using stem...

  1. Uncertainty in peat volume and soil carbon estimated using ground-penetrating radar and probing

    Treesearch

    Andrew D. Parsekian; Lee Slater; Dimitrios Ntarlagiannis; James Nolan; Stephen D. Sebestyen; Randall K. Kolka; Paul J. Hanson

    2012-01-01

    Estimating soil C stock in a peatland is highly dependent on accurate measurement of the peat volume. In this study, we evaluated the uncertainty in calculations of peat volume using high-resolution data to resolve the three-dimensional structure of a peat basin based on both direct (push probes) and indirect geophysical (ground-penetrating radar) measurements. We...

  2. A Comparison of Regional and SiteSpecific Volume Estimation Equations

    Treesearch

    Joe P. McClure; Jana Anderson; Hans T. Schreuder

    1987-01-01

    Regression equations for volume by region and site class were examined for lobiolly pine. The regressions for the Coastal Plain and Piedmont regions had significantly different slopes. The results shared important practical differences in percentage of confidence intervals containing the true total volume and in percentage of estimates within a specific proportion of...

  3. Comparison of Past, Present, and Future Volume Estimation Methods for Tennessee

    Treesearch

    Stanley J. Zarnoch; Alexander Clark; Ray A. Souter

    2003-01-01

    Forest Inventory and Analysis 1999 survey data for Tennessee were used to compare stem-volume estimates obtained using a previous method, the current method, and newly developed taper models that will be used in the future. Compared to the current method, individual tree volumes were consistently underestimated with the previous method, especially for the hardwoods....

  4. Lunar Architecture Team - Phase 2 Habitat Volume Estimation: "Caution When Using Analogs"

    NASA Technical Reports Server (NTRS)

    Rudisill, Marianne; Howard, Robert; Griffin, Brand; Green, Jennifer; Toups, Larry; Kennedy, Kriss

    2008-01-01

    The lunar surface habitat will serve as the astronauts' home on the moon, providing a pressurized facility for all crew living functions and serving as the primary location for a number of crew work functions. Adequate volume is required for each of these functions in addition to that devoted to housing the habitat systems and crew consumables. The time constraints of the LAT-2 schedule precluded the Habitation Team from conducting a complete "bottoms-up" design of a lunar surface habitation system from which to derive true volumetric requirements. The objective of this analysis was to quickly derive an estimated total pressurized volume and pressurized net habitable volume per crewmember for a lunar surface habitat, using a principled, methodical approach in the absence of a detailed design. Five "heuristic methods" were used: historical spacecraft volumes, human/spacecraft integration standards and design guidance, Earth-based analogs, parametric "sizing" tools, and conceptual point designs. Estimates for total pressurized volume, total habitable volume, and volume per crewmember were derived using these methods. All method were found to provide some basis for volume estimates, but values were highly variable across a wide range, with no obvious convergence of values. Best current assumptions for required crew volume were provided as a range. Results of these analyses and future work are discussed.

  5. Budget estimates: Fiscal year 1994. Volume 2: Construction of facilities

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The Construction of Facilities (CoF) appropriation provides contractual services for the repair, rehabilitation, and modification of existing facilities; the construction of new facilities and the acquisition of related collateral equipment; the acquisition or condemnation of real property; environmental compliance and restoration activities; the design of facilities projects; and advanced planning related to future facilities needs. Fiscal year 1994 budget estimates are broken down according to facility location of project and by purpose.

  6. New Martian valley network volume estimate consistent with ancient ocean and warm and wet climate

    NASA Astrophysics Data System (ADS)

    Luo, Wei; Cang, Xuezhi; Howard, Alan D.

    2017-06-01

    The volume of Martian valley network (VN) cavity and the amount of water needed to create the cavity by erosion are of significant importance for understanding the early Martian climate, the style and rate of hydrologic cycling, and the possibility of an ancient ocean. However, previous attempts at estimating these two quantities were based on selected valleys or at local sites using crude estimates of VN length, width and depth. Here we employed an innovative progressive black top hat transformation method to estimate them on a global scale based on the depth of each valley pixel. The conservative estimate of the minimum global VN volume is 1.74 × 1014 m3 and minimum cumulative volume of water required is 6.86 × 1017 m3 (or ~5 km of global equivalent layer, GEL). Both are much larger than previous estimates and are consistent with an early warm and wet climate with active hydrologic cycling involving an ocean.

  7. An assessment of the impact of FIA's default assumptions on the estimates of coarse woody debris volume and biomass

    Treesearch

    Vicente J. Monleon

    2009-01-01

    Currently, Forest Inventory and Analysis estimation procedures use Smalian's formula to compute coarse woody debris (CWD) volume and assume that logs lie horizontally on the ground. In this paper, the impact of those assumptions on volume and biomass estimates is assessed using 7 years of Oregon's Phase 2 data. Estimates of log volume computed using Smalian...

  8. Relationship of ventricular arrhythmias to the angiographically and scintigraphically estimated extent of ventricular damage late after myocardial infarction

    SciTech Connect

    Huikuri, H.V.; Korhonen, U.R.; Linnaluoto, M.K.; Takkunen, J.T.

    1987-03-01

    In order to study the quantitative relationship of ventricular arrhythmias to myocardial damage and ischemia, 61 patients with a previous myocardial infarction (at least 6 months previously) were studied by 24-hour ambulatory ECG monitoring, cardiac catheterization, and thallium-201 scintigraphy. Thirty-five patients (57%) had no ectopic beats or only infrequent, unifocal ones and 26 patients (43%) had complex ventricular arrhythmias. Left ventricular function was lower in the latter, but the number of diseased vessels did not differ in the two groups. The reduction of thallium activity in the infarct area was more marked in patients with complex arrhythmias. Multiple thallium defects were not more common in arrhythmia patients, however. These data support the view that complex ventricular arrhythmias are more closely related to the severity of ventricular damage than the presence of myocardial ischemia remote to the area of previous infarction.

  9. ICPP tank farm closure study. Volume 3: Cost estimates, planning schedules, yearly cost flowcharts, and life-cycle cost estimates

    SciTech Connect

    1998-02-01

    This volume contains information on cost estimates, planning schedules, yearly cost flowcharts, and life-cycle costs for the six options described in Volume 1, Section 2: Option 1 -- Total removal clean closure; No subsequent use; Option 2 -- Risk-based clean closure; LLW fill; Option 3 -- Risk-based clean closure; CERCLA fill; Option 4 -- Close to RCRA landfill standards; LLW fill; Option 5 -- Close to RCRA landfill standards; CERCLA fill; and Option 6 -- Close to RCRA landfill standards; Clean fill. This volume is divided into two portions. The first portion contains the cost and planning schedule estimates while the second portion contains life-cycle costs and yearly cash flow information for each option.

  10. Estimation of adipose compartment volumes in CT images of a mastectomy specimen

    NASA Astrophysics Data System (ADS)

    Imran, Abdullah-Al-Zubaer; Pokrajac, David D.; Maidment, Andrew D. A.; Bakic, Predrag R.

    2016-03-01

    Anthropomorphic software breast phantoms have been utilized for preclinical quantitative validation of breast imaging systems. Efficacy of the simulation-based validation depends on the realism of phantom images. Anatomical measurements of the breast tissue, such as the size and distribution of adipose compartments or the thickness of Cooper's ligaments, are essential for the realistic simulation of breast anatomy. Such measurements are, however, not readily available in the literature. In this study, we assessed the statistics of adipose compartments as visualized in CT images of a total mastectomy specimen. The specimen was preserved in formalin, and imaged using a standard body CT protocol and high X-ray dose. A human operator manually segmented adipose compartments in reconstructed CT images using ITK-SNAP software, and calculated the volume of each compartment. In addition, the time needed for the manual segmentation and the operator's confidence were recorded. The average volume, standard deviation, and the probability distribution of compartment volumes were estimated from 205 segmented adipose compartments. We also estimated the potential correlation between the segmentation time, operator's confidence, and compartment volume. The statistical tests indicated that the estimated compartment volumes do not follow the normal distribution. The compartment volumes are found to be correlated with the segmentation time; no significant correlation between the volume and the operator confidence. The performed study is limited by the mastectomy specimen position. The analysis of compartment volumes will better inform development of more realistic breast anatomy simulation.

  11. Pyroclastic density current volume estimation after the 2010 Merapi volcano eruption using X-band SAR

    NASA Astrophysics Data System (ADS)

    Bignami, Christian; Ruch, Joel; Chini, Marco; Neri, Marco; Buongiorno, Maria Fabrizia; Hidayati, Sri; Sayudi, Dewi Sri; Surono

    2013-07-01

    Pyroclastic density current deposits remobilized by water during periods of heavy rainfall trigger lahars (volcanic mudflows) that affect inhabited areas at considerable distance from volcanoes, even years after an eruption. Here we present an innovative approach to detect and estimate the thickness and volume of pyroclastic density current (PDC) deposits as well as erosional versus depositional environments. We use SAR interferometry to compare an airborne digital surface model (DSM) acquired in 2004 to a post eruption 2010 DSM created using COSMO-SkyMed satellite data to estimate the volume of 2010 Merapi eruption PDC deposits along the Gendol river (Kali Gendol, KG). Results show PDC thicknesses of up to 75 m in canyons and a volume of about 40 × 106 m3, mainly along KG, and at distances of up to 16 km from the volcano summit. This volume estimate corresponds mainly to the 2010 pyroclastic deposits along the KG - material that is potentially available to produce lahars. Our volume estimate is approximately twice that estimated by field studies, a difference we consider acceptable given the uncertainties involved in both satellite- and field-based methods. Our technique can be used to rapidly evaluate volumes of PDC deposits at active volcanoes, in remote settings and where continuous activity may prevent field observations.

  12. Block volume estimation from the discontinuity spacing measurements of mesozoic limestone quarries, Karaburun Peninsula, Turkey.

    PubMed

    Elci, Hakan; Turk, Necdet

    2014-01-01

    Block volumes are generally estimated by analyzing the discontinuity spacing measurements obtained either from the scan lines placed over the rock exposures or the borehole cores. Discontinuity spacing measurements made at the Mesozoic limestone quarries in Karaburun Peninsula were used to estimate the average block volumes that could be produced from them using the suggested methods in the literature. The Block Quality Designation (BQD) ratio method proposed by the authors has been found to have given in the same order of the rock block volume to the volumetric joint count (J(v)) method. Moreover, dimensions of the 2378 blocks produced between the years of 2009 and 2011 in the working quarries have been recorded. Assuming, that each block surfaces is a discontinuity, the mean block volume (V(b)), the mean volumetric joint count (J(vb)) and the mean block shape factor of the blocks are determined and compared with the estimated mean in situ block volumes (V(in)) and volumetric joint count (J(vi)) values estimated from the in situ discontinuity measurements. The established relations are presented as a chart to be used in practice for estimating the mean volume of blocks that can be obtained from a quarry site by analyzing the rock mass discontinuity spacing measurements.

  13. Block Volume Estimation from the Discontinuity Spacing Measurements of Mesozoic Limestone Quarries, Karaburun Peninsula, Turkey

    PubMed Central

    Elci, Hakan; Turk, Necdet

    2014-01-01

    Block volumes are generally estimated by analyzing the discontinuity spacing measurements obtained either from the scan lines placed over the rock exposures or the borehole cores. Discontinuity spacing measurements made at the Mesozoic limestone quarries in Karaburun Peninsula were used to estimate the average block volumes that could be produced from them using the suggested methods in the literature. The Block Quality Designation (BQD) ratio method proposed by the authors has been found to have given in the same order of the rock block volume to the volumetric joint count (Jv) method. Moreover, dimensions of the 2378 blocks produced between the years of 2009 and 2011 in the working quarries have been recorded. Assuming, that each block surfaces is a discontinuity, the mean block volume (Vb), the mean volumetric joint count (Jvb) and the mean block shape factor of the blocks are determined and compared with the estimated mean in situ block volumes (Vin) and volumetric joint count (Jvi) values estimated from the in situ discontinuity measurements. The established relations are presented as a chart to be used in practice for estimating the mean volume of blocks that can be obtained from a quarry site by analyzing the rock mass discontinuity spacing measurements. PMID:24696642

  14. Budget estimates: Fiscal year 1994. Volume 1: Agency summary

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The NASA FY 1994 budget request of $15,265 million concentrates on (1) investing in the development of new technologies including a particularly aggressive program in aeronautical technology to improve the competitive position of the United States, through shared involvement with industry and other government agencies; (2) continuing the nation's premier program of space exploration, to expand our knowledge of the solar system and the universe as well as the earth; and (3) providing safe and assured access to space using both the space shuttle and expendable launch vehicles. Budget estimates are presented for (1) research and development, including space station, space transportation capability development, space science and applications programs, space science, life and microgravity sciences and applications, mission to planet earth, space research and technology, commercial programs, aeronautics technology programs, safety and mission quality, academic programs, and tracking and data advanced systems; and (2) space operations, including space transportation programs, launch services, and space communications.

  15. Hand volume estimates based on a geometric algorithm in comparison to water displacement.

    PubMed

    Mayrovitz, H N; Sims, N; Hill, C J; Hernandez, T; Greenshner, A; Diep, H

    2006-06-01

    Assessing changes in upper extremity limb volume during lymphedema therapy is important for determining treatment efficacy and documenting outcomes. Although arm volumes may be determined by tape measure, the suitability of circumference measurements to estimate hand volumes is questionable because of the deviation in circularity of hand shape. Our aim was to develop an alternative measurement procedure and algorithm for routine use to estimate hand volumes. A caliper was used to measure hand width and depth in 33 subjects (66 hands) and volumes (VE) were calculated using an elliptical frustum model. Using regression analysis and limits of agreement (LOA), VE was compared to volumes determined by water displacement (VW), to volumes calculated from tape-measure determined circumferences (VC), and to a trapezoidal model (VT). VW and VE (mean +/- SD) were similar (363 +/- 98 vs. 362 +/-100 ml) and highly correlated; VE = 1.01VW -3.1 ml, r=0.986, p<0.001, with LOA of +/- 33.5 ml and +/- 9.9 %. In contrast, VC (480 +/- 138 ml) and VT (432 +/- 122 ml) significantly overestimated volume (p<0.0001). These results indicate that the elliptical algorithm can be a useful alternative to water displacement when hand volumes are needed and the water displacement method is contra-indicated, impractical to implement, too time consuming or not available.

  16. Splenic infarction

    MedlinePlus

    Splenic infarction is the death of tissue (necrosis) in the spleen due to a blockage in blood flow. ... Common causes of splenic infarction include: Blood clots Blood diseases such as sickle cell anemia Infections such as endocarditis

  17. Estimation of tephra volumes from sparse and incompletely observed deposit thicknesses

    NASA Astrophysics Data System (ADS)

    Green, Rebecca M.; Bebbington, Mark S.; Jones, Geoff; Cronin, Shane J.; Turner, Michael B.

    2016-04-01

    We present a Bayesian statistical approach to estimate volumes for a series of eruptions from an assemblage of sparse proximal and distal tephra (volcanic ash) deposits. Most volume estimates are of widespread tephra deposits from large events using isopach maps constructed from observations at exposed locations. Instead, we incorporate raw thickness measurements, focussing on tephra thickness data from cores extracted from lake sediments and through swamp deposits. This facilitates investigation into the dispersal pattern and volume of tephra from much smaller eruption events. Given the general scarcity of data and the physical phenomena governing tephra thickness attenuation, a hybrid Bayesian-empirical tephra attenuation model is required. Point thickness observations are modeled as a function of the distance and angular direction of each location. The dispersal of tephra from larger well-estimated eruptions are used as leverage for understanding the smaller unknown events, and uncertainty in thickness measurements can be properly accounted for. The model estimates the wind and site-specific effects on the tephra deposits in addition to volumes. Our technique is exemplified on a series of tephra deposits from Mt Taranaki (New Zealand). The resulting estimates provide a comprehensive record suitable for supporting hazard models. Posterior mean volume estimates range from 0.02 to 0.26 km 3. Preliminary examination of the results suggests a size-predictable relationship.

  18. Inter-Method Discrepancies in Brain Volume Estimation May Drive Inconsistent Findings in Autism

    PubMed Central

    Katuwal, Gajendra J.; Baum, Stefi A.; Cahill, Nathan D.; Dougherty, Chase C.; Evans, Eli; Evans, David W.; Moore, Gregory J.; Michael, Andrew M.

    2016-01-01

    Previous studies applying automatic preprocessing methods on Structural Magnetic Resonance Imaging (sMRI) report inconsistent neuroanatomical abnormalities in Autism Spectrum Disorder (ASD). In this study we investigate inter-method differences as a possible cause behind these inconsistent findings. In particular, we focus on the estimation of the following brain volumes: gray matter (GM), white matter (WM), cerebrospinal fluid (CSF), and total intra cranial volume (TIV). T1-weighted sMRIs of 417 ASD subjects and 459 typically developing controls (TDC) from the ABIDE dataset were estimated using three popular preprocessing methods: SPM, FSL, and FreeSurfer (FS). Brain volumes estimated by the three methods were correlated but had significant inter-method differences; except TIVSPM vs. TIVFS, all inter-method differences were significant. ASD vs. TDC group differences in all brain volume estimates were dependent on the method used. SPM showed that TIV, GM, and CSF volumes of ASD were larger than TDC with statistical significance, whereas FS and FSL did not show significant differences in any of the volumes; in some cases, the direction of the differences were opposite to SPM. When methods were compared with each other, they showed differential biases for autism, and several biases were larger than ASD vs. TDC differences of the respective methods. After manual inspection, we found inter-method segmentation mismatches in the cerebellum, sub-cortical structures, and inter-sulcal CSF. In addition, to validate automated TIV estimates we performed manual segmentation on a subset of subjects. Results indicate that SPM estimates are closest to manual segmentation, followed by FS while FSL estimates were significantly lower. In summary, we show that ASD vs. TDC brain volume differences are method dependent and that these inter-method discrepancies can contribute to inconsistent neuroimaging findings in general. We suggest cross-validation across methods and emphasize the

  19. Inter-Method Discrepancies in Brain Volume Estimation May Drive Inconsistent Findings in Autism.

    PubMed

    Katuwal, Gajendra J; Baum, Stefi A; Cahill, Nathan D; Dougherty, Chase C; Evans, Eli; Evans, David W; Moore, Gregory J; Michael, Andrew M

    2016-01-01

    Previous studies applying automatic preprocessing methods on Structural Magnetic Resonance Imaging (sMRI) report inconsistent neuroanatomical abnormalities in Autism Spectrum Disorder (ASD). In this study we investigate inter-method differences as a possible cause behind these inconsistent findings. In particular, we focus on the estimation of the following brain volumes: gray matter (GM), white matter (WM), cerebrospinal fluid (CSF), and total intra cranial volume (TIV). T1-weighted sMRIs of 417 ASD subjects and 459 typically developing controls (TDC) from the ABIDE dataset were estimated using three popular preprocessing methods: SPM, FSL, and FreeSurfer (FS). Brain volumes estimated by the three methods were correlated but had significant inter-method differences; except TIVSPM vs. TIVFS, all inter-method differences were significant. ASD vs. TDC group differences in all brain volume estimates were dependent on the method used. SPM showed that TIV, GM, and CSF volumes of ASD were larger than TDC with statistical significance, whereas FS and FSL did not show significant differences in any of the volumes; in some cases, the direction of the differences were opposite to SPM. When methods were compared with each other, they showed differential biases for autism, and several biases were larger than ASD vs. TDC differences of the respective methods. After manual inspection, we found inter-method segmentation mismatches in the cerebellum, sub-cortical structures, and inter-sulcal CSF. In addition, to validate automated TIV estimates we performed manual segmentation on a subset of subjects. Results indicate that SPM estimates are closest to manual segmentation, followed by FS while FSL estimates were significantly lower. In summary, we show that ASD vs. TDC brain volume differences are method dependent and that these inter-method discrepancies can contribute to inconsistent neuroimaging findings in general. We suggest cross-validation across methods and emphasize the

  20. Maximal area and conformal welding heuristics for optimal slice selection in splenic volume estimation

    NASA Astrophysics Data System (ADS)

    Gutenko, Ievgeniia; Peng, Hao; Gu, Xianfeng; Barish, Mathew; Kaufman, Arie

    2016-03-01

    Accurate estimation of splenic volume is crucial for the determination of disease progression and response to treatment for diseases that result in enlargement of the spleen. However, there is no consensus with respect to the use of single or multiple one-dimensional, or volumetric measurement. Existing methods for human reviewers focus on measurement of cross diameters on a representative axial slice and craniocaudal length of the organ. We propose two heuristics for the selection of the optimal axial plane for splenic volume estimation: the maximal area axial measurement heuristic and the novel conformal welding shape-based heuristic. We evaluate these heuristics on time-variant data derived from both healthy and sick subjects and contrast them to established heuristics. Under certain conditions our heuristics are superior to standard practice volumetric estimation methods. We conclude by providing guidance on selecting the optimal heuristic for splenic volume estimation.

  1. Advanced Composite Cost Estimating Manual. Volume II. Appendix

    DTIC Science & Technology

    1976-08-01

    0~~~~~~; - -m- O1 .,a 0 j in N j "s w f 0 0 Av .s 00 4 164 "i’ 3. -%’ 1*4*J. - N w 0-uo 16 fo moNi o w w -Q * * 0 h" v 0 a rq)E 4.1 w 0 -0 S p4 4 4...REkMOVE CHAIS 0.00J32 06COC43 I I 34 OPIN LC-OR 0*01402 o.ci’r2 I 31 PELEA *. 1.L. L JAO4 000035 22 36 RILtLA5E VAC. LINES 0.0031 !I kfMOVF lPAIk Ptk OVL...0 - NO 1- YES Ia YES INSERTS: 0 - NO 1 - YES 59 a *1 ACCEM-S COST PROJECTION CAM I UNIT MNER~aJboo~ AVE , LOT SIZiTYPE OF ESTIMATE UNIT COST aL. 21

  2. A test of alternative estimators for volume at time 1 from remeasured point samples

    Treesearch

    Francis A. Roesch; Edwin J. Green; Charles T. Scott

    1993-01-01

    Two estimators for volume at time 1 for use with permanent horizontal point samples are evaluated. One estimator, used traditionally, uses only the trees sampled at time 1, while the second estimator, originally presented by Roesch and coauthors (F.A. Roesch, Jr., E.J. Green, and C.T. Scott. 1989. For. Sci. 35(2):281-293). takes advantage of additional sample...

  3. External validation of a forest inventory and analysis volume equation and comparisons with estimates from multiple stem-profile models

    Treesearch

    Christopher M. Oswalt; Adam M. Saunders

    2009-01-01

    Sound estimation procedures are desideratum for generating credible population estimates to evaluate the status and trends in resource conditions. As such, volume estimation is an integral component of the U.S. Department of Agriculture, Forest Service, Forest Inventory and Analysis (FIA) program's reporting. In effect, reliable volume estimation procedures are...

  4. Rapid estimate of solid volume in large tuff cores using a gas pycnometer

    SciTech Connect

    Thies, C.; Geddis, A.M.; Guzman, A.G.

    1996-09-01

    A thermally insulated, rigid-volume gas pycnometer system has been developed. The pycnometer chambers have been machined from solid PVC cylinders. Two chambers confine dry high-purity helium at different pressures. A thick-walled design ensures minimal heat exchange with the surrounding environment and a constant volume system, while expansion takes place between the chambers. The internal energy of the gas is assumed constant over the expansion. The ideal gas law is used to estimate the volume of solid material sealed in one of the chambers. Temperature is monitored continuously and incorporated into the calculation of solid volume. Temperature variation between measurements is less than 0.1{degrees}C. The data are used to compute grain density for oven-dried Apache Leap tuff core samples. The measured volume of solid and the sample bulk volume are used to estimate porosity and bulk density. Intrinsic permeability was estimated from the porosity and measured pore surface area and is compared to in-situ measurements by the air permeability method. The gas pycnometer accommodates large core samples (0.25 m length x 0.11 m diameter) and can measure solid volume greater than 2.20 cm{sup 3} with less than 1% error.

  5. Volume estimation of the thalamus using freesurfer and stereology: consistency between methods.

    PubMed

    Keller, Simon S; Gerdes, Jan S; Mohammadi, Siawoosh; Kellinghaus, Christoph; Kugel, Harald; Deppe, Katja; Ringelstein, E Bernd; Evers, Stefan; Schwindt, Wolfram; Deppe, Michael

    2012-10-01

    Freely available automated MR image analysis techniques are being increasingly used to investigate neuroanatomical abnormalities in patients with neurological disorders. It is important to assess the specificity and validity of automated measurements of structure volumes with respect to reliable manual methods that rely on human anatomical expertise. The thalamus is widely investigated in many neurological and neuropsychiatric disorders using MRI, but thalamic volumes are notoriously difficult to quantify given the poor between-tissue contrast at the thalamic gray-white matter interface. In the present study we investigated the reliability of automatically determined thalamic volume measurements obtained using FreeSurfer software with respect to a manual stereological technique on 3D T1-weighted MR images obtained from a 3 T MR system. Further to demonstrating impressive consistency between stereological and FreeSurfer volume estimates of the thalamus in healthy subjects and neurological patients, we demonstrate that the extent of agreeability between stereology and FreeSurfer is equal to the agreeability between two human anatomists estimating thalamic volume using stereological methods. Using patients with juvenile myoclonic epilepsy as a model for thalamic atrophy, we also show that both automated and manual methods provide very similar ratios of thalamic volume loss in patients. This work promotes the use of FreeSurfer for reliable estimation of global volume in healthy and diseased thalami.

  6. Volume estimation of the preepiglottic and paraglottic space using spiral computed tomography.

    PubMed

    Hermans, R; Van der Goten, A; Baert, A L

    1997-01-01

    The purpose of this study was to estimate the volume variability of the preepiglottic and paraglottic space in the normal larynx. In 23 adult patients (12 women, 11 men), a spiral CT acquisition through the larynx was obtained. No laryngeal pathology was observed. The area of the this submucosal fat space was estimated on each slice by semi-automatic segmentation; the volume was calculated by the summation-of-areas technique. The obtained volumes were correlated with body area, body mass index and gender. The mean estimated volume of the preepiglottic and paraglottic space was 2.8 ml (SD 1.7 ml, range 0.7-5.9). No correlation with body mass index (p = 0.6), but a significant correlation with body area (p < 0.001) was found. A significant volume difference was present between men (mean 4.5 ml, SD 1.0 ml, range 2.8-5.9) and women (mean 1.4 ml, SD 0.5 ml, range 0.7-2.4)(p < 0.0001). Multiple regression analysis showed gender (p < 0.0001) to be a more important variable than body area (p = 0.17) in predicting the volume of the preepiglottic and paraglottic space. In conclusion, the volume of the preepiglottic and paraglottic space appears to be very variable, and should only be analysed with consideration of the gender of the examined subjects.

  7. Estimation of volume flow rate by surface integration of velocity vectors from color Doppler images.

    PubMed

    Sun, Y; Ask, P; Janerot-Sjöberg, B; Eidenvall, L; Loyd, D; Wranne, B

    1995-01-01

    A new Doppler echocardiographically based method has been developed to quantify volume flow rate by surface integration of velocity vectors (SIVV). Electrocardiographic-gated color Doppler images acquired in two orthogonal planes were used to estimate volume flow rate through a bowl-shaped surface at a given time and distance from the probe. To provide in vitro validation, the method was tested in a hydraulic model representing a pulsatile flow system with a restrictive orifice. Accurate estimates of stroke volume (+/- 10%) were obtained in a window between 1.2 and 1.6 cm proximal to the orifice, just before the region of prestenotic acceleration. By use of the Bernoulli's equation, the estimated flows were used to generate pressure gradient waveforms across the orifice, which agreed well with the measured flows. To demonstrate in vivo applicability, the SIVV method was applied retrospectively to the determination of stroke volume and subaortic flow from the apical three-chamber and five-chamber views in two patients. Stroke volume estimates along the left ventricular outflow tract showed a characteristic similar to that in the in vitro study and agreed well with those obtained by the Fick oxygen method. The region where accurate measurements can be obtained is affected by instrumental factors including Nyquist velocity limit, wall motion filter cutoff, and color flow sector angle. The SIVV principle should be useful for quantitative assessment of the severity of valvular abnormalities and noninvasive measurement of pulsatile volume flows in general.

  8. Unbiased estimation of the calcaneus volume using the Cavalieri principle on computed tomography images.

    PubMed

    Acer, N; Bayar, B; Basaloglu, H; Oner, E; Bayar, K; Sankur, S

    2008-11-20

    The size and shape of tarsal bones are especially relevant when considering some orthopedic diseases such as clubfoot. For this reason, the measurements of the tarsal bones have been the subject of many studies, none of which has used stereological methods to estimate the volume. In the present stereological study, we estimated the volume of calcaneal bone of normal feet and dry bones. We used a combination of the Cavalieri principle and computer tomographic scans taken from eight males and nine dry calcanei to estimate the volumes of calcaneal bones. The mean volume of dry calcaneal bones was estimated, producing mean results using the point-counting method and Archimedes principle being 49.11+/-10.7 or 48.22+/-11.92 cm(3), respectively. A positive correlation was found between anthropometric measurements and the volume of calcaneal bones. The findings of the present study using the stereological methods could provide data for the evaluation of normal and pathological volumes of calcaneal bones.

  9. Consideration of QRS complex in addition to ST-segment abnormalities in the estimation of the "risk region" during acute anterior or inferior myocardial infarction.

    PubMed

    Vervaat, F E; Bouwmeester, S; van Hellemond, I E G; Wagner, G S; Gorgels, A P M

    2014-01-01

    The myocardial area at risk (MaR) is an important aspect in acute ST-elevation myocardial infarction (STEMI). It represents the myocardium at the onset of the STEMI that is ischemic and could become infarcted if no reperfusion occurs. The MaR, therefore, has clinical value because it gives an indication of the amount of myocardium that could potentially be salvaged by rapid reperfusion therapy. The most validated method for measuring the MaR is (99m)Tc-sestamibi SPECT, but this technique is not easily applied in the clinical setting. Another method that can be used for measuring the MaR is the standard ECG-based scoring system, Aldrich ST score, which is more easily applied. This ECG-based scoring system can be used to estimate the extent of acute ischemia for anterior or inferior left ventricular locations, by considering quantitative changes in the ST-segment. Deviations in the ST-segment baseline that occur following an acute coronary occlusion represent the ischemic changes in the transmurally ischemic myocardium. In most instances however, the ECG is not available at the very first moments of STEMI and as times passes the ischemic myocardium becomes necrotic with regression of the ST-segment deviation along with progressive changes of the QRS complex. Thus over the time course of the acute event, the Aldrich ST score would be expected to progressively underestimate the MaR, as was seen in studies with SPECT as gold standard; anterior STEMI (r=0.21, p=0.32) and inferior STEMI (r=0.17, p=0.36). Another standard ECG-based scoring system is the Selvester QRS score, which can be used to estimate the final infarct size by considering the quantitative changes in the QRS complex. Therefore, additional consideration of the Selvester QRS score in the acute phase could potentially provide the "component" of infarcted myocardium that is missing when the Aldrich ST score alone is used to determine the MaR in the acute phase, as was seen in studies with SPECT as gold

  10. Improved pressure-volume-temperature method for estimation of cryogenic liquid volume

    NASA Astrophysics Data System (ADS)

    Seo, Mansu; Jeong, Sangkwon; Jung, Young-suk; Kim, Jakyung; Park, Hana

    2012-04-01

    One of the most important issues in a liquid propellant rocket is to measure the amount of remaining liquid propellant under low gravity environment during space mission. This paper presents the results of experiment and analysis of a pressure-volume-temperature (PVT) method which is a gauging method for low gravity environment. The experiment is conducted using 7.4 l tank for liquid nitrogen with various liquid-fill levels. To maximize the accuracy of a PVT method with minimum hardware, the technique of a helium injection with low mass flow rate is applied to maintain stable temperature profile in the ullage volume. The PVT analysis considering both pressurant and cryogen as a binary mixture is suggested. At high liquid-fill levels of 72-80%, the accuracy from the conventional PVT analysis is within 4.6%. At low fill levels of 27-30%, the gauging error is within 3.4% by mixture analysis of a PVT method with specific low mass flow rate of a helium injection. It is concluded that the proper mass flow rate of a helium injection and PVT analyses are crucial to enhance the accuracy of the PVT method with regard to various liquid-fill levels.

  11. Foot volume estimates based on a geometric algorithm in comparison to water displacement.

    PubMed

    Mayrovitz, H N; Sims, N; Litwin, B; Pfister, S

    2005-03-01

    Assessing lower extremity limb volume and its change during and after lymphedema therapy is important for determining treatment efficacy and documenting outcomes. Although leg volumes may be determined by tape measure and other methods, there is no metric method to routinely assess foot volumes. Exclusion of foot volumes can under- or overestimate therapeutic progress. Our aim was to develop and test a metric measurement procedure and algorithm for practicing therapists to use to estimate foot volumes. The method uses a caliper and ruler to measure foot dimensions at standardized locations and calculates foot volume (VM) by a mathematical algorithm. VM was compared to volumes measured by water displacement (Vw) in 30 subjects (60 feet) using regression analysis and limits of agreement (LOA). Vw and VM (mean +/- sd) were similar 857 +/- 150 ml vs. 859 +/- 154 ml, and were highly correlated VM = 1.00Vw + 1.67 ml, r = 0.965, p < 0.001. The LOA for absolute volume differences and percentages were respectively +/- 79.6 ml and +/- 9.28 %. These results indicate that this metric method can be a useful alternative to water displacement when foot volumes are needed, but the water displacement method is contraindicated, impractical to implement, too time consuming or is not available.

  12. Achieving a new dimension: children integrate three stimulus dimensions in volume estimations.

    PubMed

    Ebersbach, Mirjam

    2009-05-01

    Although J. Piaget (1968) assumed that children up to 7 years old are unable to consider more than 1 stimulus dimension in their judgments, subsequent research has demonstrated that preschoolers can consider 2 dimensions, such as the width and length of rectangles to estimate their area (F. Wilkening, 1979). The present study addressed the question of whether children can also take 3 stimulus dimensions into account. Kindergartners, 1st and 3rd graders, and adults (N = 73) estimated the volume of cuboids that required the consideration of 3 dimensions: width, height, and length. The results showed that the majority of kindergartners already based their volume estimations on all 3 dimensions. A considerable proportion of kindergartners even integrated width, height, and length multiplicatively. There was no dramatic improvement with age, implying the implicit understanding of volume to develop relatively early in childhood. The results are discussed in light of children's cognitive competencies concerning multidimensional reasoning. Copyright 2009 APA, all rights reserved

  13. Volcanic eruption volume flux estimations from very long period infrasound signals

    NASA Astrophysics Data System (ADS)

    Yamada, Taishi; Aoyama, Hiroshi; Nishimura, Takeshi; Iguchi, Masato; Hendrasto, Muhamad

    2017-01-01

    We examine very long period infrasonic signals accompanying volcanic eruptions near active vents at Lokon-Empung volcano in Indonesia, Aso, Kuchinoerabujima, and Kirishima volcanoes in Japan. The excitation of the very long period pulse is associated with an explosion, the emerging of an eruption column, and a pyroclastic density current. We model the excitation of the infrasound pulse, assuming a monopole source, to quantify the volume flux and cumulative volume of erupting material. The infrasound-derived volume flux and cumulative volume can be less than half of the video-derived results. A largely positive correlation can be seen between the infrasound-derived volume flux and the maximum eruption column height. Therefore, our result suggests that the analysis of very long period volcanic infrasound pulses can be helpful in estimating the maximum eruption column height.

  14. Estimated maximal and current brain volume predict cognitive ability in old age.

    PubMed

    Royle, Natalie A; Booth, Tom; Valdés Hernández, Maria C; Penke, Lars; Murray, Catherine; Gow, Alan J; Maniega, Susana Muñoz; Starr, John; Bastin, Mark E; Deary, Ian J; Wardlaw, Joanna M

    2013-12-01

    Brain tissue deterioration is a significant contributor to lower cognitive ability in later life; however, few studies have appropriate data to establish how much influence prior brain volume and prior cognitive performance have on this association. We investigated the associations between structural brain imaging biomarkers, including an estimate of maximal brain volume, and detailed measures of cognitive ability at age 73 years in a large (N = 620), generally healthy, community-dwelling population. Cognitive ability data were available from age 11 years. We found positive associations (r) between general cognitive ability and estimated brain volume in youth (male, 0.28; females, 0.12), and in measured brain volume in later life (males, 0.27; females, 0.26). Our findings show that cognitive ability in youth is a strong predictor of estimated prior and measured current brain volume in old age but that these effects were the same for both white and gray matter. As 1 of the largest studies of associations between brain volume and cognitive ability with normal aging, this work contributes to the wider understanding of how some early-life factors influence cognitive aging. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Estimated maximal and current brain volume predict cognitive ability in old age

    PubMed Central

    Royle, Natalie A.; Booth, Tom; Valdés Hernández, Maria C.; Penke, Lars; Murray, Catherine; Gow, Alan J.; Maniega, Susana Muñoz; Starr, John; Bastin, Mark E.; Deary, Ian J.; Wardlaw, Joanna M.

    2013-01-01

    Brain tissue deterioration is a significant contributor to lower cognitive ability in later life; however, few studies have appropriate data to establish how much influence prior brain volume and prior cognitive performance have on this association. We investigated the associations between structural brain imaging biomarkers, including an estimate of maximal brain volume, and detailed measures of cognitive ability at age 73 years in a large (N = 620), generally healthy, community-dwelling population. Cognitive ability data were available from age 11 years. We found positive associations (r) between general cognitive ability and estimated brain volume in youth (male, 0.28; females, 0.12), and in measured brain volume in later life (males, 0.27; females, 0.26). Our findings show that cognitive ability in youth is a strong predictor of estimated prior and measured current brain volume in old age but that these effects were the same for both white and gray matter. As 1 of the largest studies of associations between brain volume and cognitive ability with normal aging, this work contributes to the wider understanding of how some early-life factors influence cognitive aging. PMID:23850342

  16. Space Shuttle propulsion parameter estimation using optimal estimation techniques, volume 1

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The mathematical developments and their computer program implementation for the Space Shuttle propulsion parameter estimation project are summarized. The estimation approach chosen is the extended Kalman filtering with a modified Bryson-Frazier smoother. Its use here is motivated by the objective of obtaining better estimates than those available from filtering and to eliminate the lag associated with filtering. The estimation technique uses as the dynamical process the six degree equations-of-motion resulting in twelve state vector elements. In addition to these are mass and solid propellant burn depth as the ""system'' state elements. The ""parameter'' state elements can include aerodynamic coefficient, inertia, center-of-gravity, atmospheric wind, etc. deviations from referenced values. Propulsion parameter state elements have been included not as options just discussed but as the main parameter states to be estimated. The mathematical developments were completed for all these parameters. Since the systems dynamics and measurement processes are non-linear functions of the states, the mathematical developments are taken up almost entirely by the linearization of these equations as required by the estimation algorithms.

  17. A Novel Calculation to Estimate Blood Volume and Hematocrit During Bypass

    PubMed Central

    Trowbridge, Cody; Stammers, Alfred; Klayman, Myra; Brindisi, Nicholas

    2008-01-01

    Abstract: Patient blood volume impacts most facets of perfusion care, including volume management, transfusion practices, and pharmacologic interventions Unfortunately, there is a wide variability in individual blood volumes, and experimental measurement is not practical in the clinical environment. The purpose of this study was to evaluate a mathematical algorithm for estimating individual blood volume. After institutional review board approval, volumetric and transfusion data were prospectively collected for 165 patients and applied to a series of calculations. The resultant blood volume estimate (BVE) was used to predict the first and last bypass hematocrit. The estimated hematocrits using both BVE and 65 mL/kg were compared with measured hematocrits using the Pearson moment correlation coefficient and the Bland Altman measures of accuracy and precision. There was a wide range of BVE (minimum, 35 mL/kg; mean ± SD, 64 ± 22 mL/kg; maximum, 129 mL/kg). Using BVE, the estimated hematocrit was similar to the measured first (24.7 ± 6.4% vs. 24.5 ± 6.2%, r = 0.9884, p > .05) and last (24.5 ± 5.9% vs. 25.1 ± 5.7%, r = 0.9001, p > .05) bypass hematocrit. Using 65 mL/kg resulted in a larger difference between estimated and measured hematocrits for the first (25.6 ± 4.5% vs. 24.5 ± 6.2%, r = 0.6885, p = .030) and last (23.8 ± 3.6% vs. 25.1 ± 5.7%, r = 0.5990, p = .001) bypass hematocrits. Compared with using 65 mL/kg for blood volume, the BVE allowed for a more precise estimated hematocrit during CPB. PMID:18389667

  18. A comparison of four estimates of Arctic sea ice thickness and volume

    NASA Astrophysics Data System (ADS)

    Tilling, R.; Ridout, A.; Shepherd, A.

    2016-12-01

    In April 2010 the European Space Agency (ESA) CryoSat-2 satellite was launched, providing unprecedented sampling of the Arctic Ocean with a region of coverage extending to 88°N. The first estimates of Arctic sea ice thickness from CryoSat-2 were produced in 2013 [Laxon et al., 2013] by the Centre for Polar Observation and Modelling (CPOM). Since then, a number of other teams have developed alternative CryoSat-2 sea ice processing systems, including NASA [Kurtz et al., 2014], and the Alfred Wegener Institute (AWI) [Ricker et al., 2014]. In addition, the Pan-Arctic Ice-Ocean Modelling and Assimilation System (PIOMAS) model also provides an estimate of Arctic sea ice thickness. These four data records of Arctic sea ice thickness differ in their methods and spatial extent. In this paper, we compare and contrast estimates of sea ice thickness and volume derived from these four data records - the CPOM, NASA, AWI, and PIOMAS systems. We also investigate the sensitivity of each dataset to the application of a time-varying snow load instead of the climatology that is conventionally employed. To facilitate the comparison, sea ice thickness and concentration data are posted on to the same monthly grid to produce equivalent estimates of Arctic sea ice volume. An initial comparison is shown in Figure 1. All of the datasets display, qualitatively, many of the same aspects of the observed variability in volume, including seasonal progression and the step increases in sea ice volume recorded in the autumns of 2013 and 2014. However, CPOM estimates of volume are generally lower than those from AWI in October, similar in November, and higher through the remainder of the growth season. PIOMAS estimates of Arctic sea ice volume are more variable.

  19. Comparison of three methods for the estimation of pineal gland volume using magnetic resonance imaging.

    PubMed

    Acer, Niyazi; Ilıca, Ahmet Turan; Turgut, Ahmet Tuncay; Ozçelik, Ozlem; Yıldırım, Birdal; Turgut, Mehmet

    2012-01-01

    Pineal gland is a very important neuroendocrine organ with many physiological functions such as regulating circadian rhythm. Radiologically, the pineal gland volume is clinically important because it is usually difficult to distinguish small pineal tumors via magnetic resonance imaging (MRI). Although many studies have estimated the pineal gland volume using different techniques, to the best of our knowledge, there has so far been no stereological work done on this subject. The objective of the current paper was to determine the pineal gland volume using stereological methods and by the region of interest (ROI) on MRI. In this paper, the pineal gland volumes were calculated in a total of 62 subjects (36 females, 26 males) who were free of any pineal lesions or tumors. The mean ± SD pineal gland volumes of the point-counting, planimetry, and ROI groups were 99.55 ± 51.34, 102.69 ± 40.39, and 104.33 ± 40.45 mm(3), respectively. No significant difference was found among the methods of calculating pineal gland volume (P > 0.05). From these results, it can be concluded that each technique is an unbiased, efficient, and reliable method, ideally suitable for in vivo examination of MRI data for pineal gland volume estimation.

  20. Comparison of Three Methods for the Estimation of Pineal Gland Volume Using Magnetic Resonance Imaging

    PubMed Central

    Acer, Niyazi; Ilıca, Ahmet Turan; Turgut, Ahmet Tuncay; Özçelik, Özlem; Yıldırım, Birdal; Turgut, Mehmet

    2012-01-01

    Pineal gland is a very important neuroendocrine organ with many physiological functions such as regulating circadian rhythm. Radiologically, the pineal gland volume is clinically important because it is usually difficult to distinguish small pineal tumors via magnetic resonance imaging (MRI). Although many studies have estimated the pineal gland volume using different techniques, to the best of our knowledge, there has so far been no stereological work done on this subject. The objective of the current paper was to determine the pineal gland volume using stereological methods and by the region of interest (ROI) on MRI. In this paper, the pineal gland volumes were calculated in a total of 62 subjects (36 females, 26 males) who were free of any pineal lesions or tumors. The mean ± SD pineal gland volumes of the point-counting, planimetry, and ROI groups were 99.55 ± 51.34, 102.69 ± 40.39, and 104.33 ± 40.45 mm3, respectively. No significant difference was found among the methods of calculating pineal gland volume (P > 0.05). From these results, it can be concluded that each technique is an unbiased, efficient, and reliable method, ideally suitable for in vivo examination of MRI data for pineal gland volume estimation. PMID:22619577

  1. Uncertainty in NAPL volume estimates due to random measurement errors during partitioning tracer tests.

    PubMed

    Brooks, Michael C; Wise, William R

    2005-09-15

    The uncertainty in NAPL volume estimates obtained through partitioning tracers can be quantified as a function of random errors in volume and concentration measurements when moments are calculated from experimentally measured breakthrough curves using the trapezoidal rule for numerical integration. The methodology is based upon standard stochastic methods for random error propagation. Monte Carlo simulations using a synthetic data set derived from the one-dimensional solution of the advective-dispersive equation serve to verify the process. It is shown that the uncertainty in NAPL volume predictions nonlinearly increases as the retardation factor decreases. An important result of this observation is that there is a large degree of uncertainty in using partitioning tracers to conclude NAPL is absent from the swept zone. Under the conditions investigated, random errors in concentration measurements are shown to have a greater impact on NAPL volume uncertainty than random errors in volume measurements, and it is also shown that uncertainty in NAPL volume decreases as the resolution of the breakthrough curves increases. The impact of uncertainty in background retardation (i.e., sorption of partitioning tracers in the absence of NAPL) was also investigated, and it likewise indicated that the relative uncertainty in NAPL volume estimates increases as the retardation factor decreases.

  2. Optimal volume Wegner estimate for random magnetic Laplacians on Z2

    NASA Astrophysics Data System (ADS)

    Hasler, David; Luckett, Daniel

    2013-03-01

    We consider a two dimensional magnetic Schrödinger operator on a square lattice with a spatially stationary random magnetic field. We prove a Wegner estimate with optimal volume dependence. The Wegner estimate holds around the spectral edges, and it implies Hölder continuity of the integrated density of states in this region. The proof is based on the Wegner estimate obtained in Erdős and Hasler ["Wegner estimate for random magnetic Laplacians on {{Z}}^2," Ann. Henri Poincaré 12, 1719-1731 (2012)], 10.1007/s00023-012-0177-9.

  3. Optimization Of Coherence Estimation Window Size Aiming At Growing Stock Volume Retrieval In Siberian Forest

    NASA Astrophysics Data System (ADS)

    Stelmaszczuk-Gorska, Martyna; Thiel, Christian; Schmullius, Christiane

    2013-12-01

    This research was conducted to find the optimal coherence estimation window size aiming at growing stock volume (GSV) retrieval in Siberian Forest. Additionally, the properties of ALOS PALSAR L-band interferometric coherence of Siberian boreal forest have been presented. It was confirmed that the data acquired during frozen conditions are better suited for the growing stock volume retrieval, showing high coherence for sparse forest and low coherence for dense forest. It was concluded that at least ~ 60 equivalent number of looks (ENL) are necessary to achieve a compromise between a good spatial resolution and reliable estimation of coherence using ALOS PALSAR FBS images for Siberian forest.

  4. Estimation of convective rain volumes utilizing the are-time-integral technique

    NASA Technical Reports Server (NTRS)

    Johnson, L. Ronald; Smith, Paul L.

    1990-01-01

    Interest in the possibility of developing useful estimates of convective rainfall with Area-Time Integral (ATI) methods is increasing. The basis of the ATI technique is the observed strong correlation between rainfall volumes and ATI values. This means that rainfall can be estimated by just determining the ATI values, if previous knowledge of the relationship to rain volume is available to calibrate the technique. Examples are provided of the application of the ATI approach to gage, radar, and satellite measurements. For radar data, the degree of transferability in time and among geographical areas is examined. Recent results on transferability of the satellite ATI calculations are presented.

  5. Morphological MRI characteristics of recent small subcortical infarcts.

    PubMed

    Gattringer, Thomas; Eppinger, Sebastian; Pinter, Daniela; Pirpamer, Lukas; Berghold, Andrea; Wünsch, Gerit; Ropele, Stefan; Wardlaw, Joanna M; Enzinger, Christian; Fazekas, Franz

    2015-10-01

    New imaging criteria for recent small subcortical infarcts have recently been proposed, replacing the earlier term 'lacunar infarction', but their applicability and impact on lesion selection is yet unknown. To collect information on the morphologic characteristics and variability of recent small subcortical infarcts on magnetic resonance imaging in regard to lesion location and demographic variables. We identified all patients with acute stroke and cerebral magnetic resonance imaging from 2008 to 2013 in our hospital database and selected those with a single recent small subcortical infarct defined by an estimated maximal axial diameter of 20 mm. Recent small subcortical infarcts were segmented on diffusion-weighted imaging and fluid-attenuated inversion recovery sequence to calculate the largest axial and longitudinal diameter and lesion volume. We assessed morphometric differences of recent small subcortical infarcts regarding location and demographic variables and the impact of different recent small subcortical infarct definitions on lesion selection. Three hundred forty-four patients (median age 72; range 25-92 years, 65% male) were selected. Most recent small subcortical infarcts were located in the basal ganglia (n = 111), followed by pons (n = 92), thalamus (n = 77), and centrum semiovale (n = 64). Quantitative measurements confirmed visual assessment of the axial diameter in 95%. All morphometric variables were strongly intercorrelated and comparable on diffusion-weighted imaging and fluid-attenuated inversion recovery sequence. Recent small subcortical infarcts in the basal ganglia were significantly larger both in the axial and longitudinal direction compared with other regions. Dichotomization of recent small subcortical infarcts according to axial (≤ / >15 mm) or longitudinal (≤ / >20 mm) sizes resulted in different regional frequencies and distributions. Age, gender, and time from stroke onset to magnetic resonance imaging

  6. Validation of Test Weighing Protocol to Estimate Enteral Feeding Volumes in Preterm Infants.

    PubMed

    Rankin, Michael W; Jimenez, Elizabeth Yakes; Caraco, Marina; Collinson, Marie; Lostetter, Lisa; DuPont, Tara L

    2016-11-01

    To evaluate the accuracy of pre- and postfeeding weights to estimate enteral feeding volumes in preterm infants. Single-center prospective cohort study of infants 28-36 weeks' corrected age receiving gavage feedings. For each test weight, 3 pre- and 3 postgavage feeding weights were obtained by study personnel, blinded to feeding volume, via a specific protocol. The correlation between test weight difference and actual volume ingested was assessed by the use of summary statistics, Spearman rho, and graphical analyses. The relationship between categorical predictive variables and a predefined acceptable difference (±5 mL) was assessed with the χ(2) or Fisher exact test. A total of 101 test weights were performed in 68 infants. Estimated and actual feeding volumes were highly correlated (r = 0.94, P < .001), with a mean absolute difference of 2.95 mL (SD: 2.70; range: 0, 12.3 mL; 5th, 95th percentile: 0, 9.3); 85% of test weights were within ±5 mL of actual feeding volume and did not vary significantly by corrected age, feeding tube or respiratory support type, feeding duration or volume, formula vs breast milk, or caloric density. With adherence to study protocol, 89% of test weights (66/74) were within ±5 mL of actual volume, compared with 71% (19/27, P = .04) when concerns about protocol adherence were noted (eg, difficulty securing oxygen tubing). Via the use of a standard protocol, feeding volumes can be estimated accurately by pre- and postfeeding weights. Test weighing could be a valuable tool to support direct breastfeeding in the neonatal intensive care unit. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Estimating stem volume and biomass of Pinus koraiensis using LiDAR data.

    PubMed

    Kwak, Doo-Ahn; Lee, Woo-Kyun; Cho, Hyun-Kook; Lee, Seung-Ho; Son, Yowhan; Kafatos, Menas; Kim, So-Ra

    2010-07-01

    The objective of this study was to estimate the stem volume and biomass of individual trees using the crown geometric volume (CGV), which was extracted from small-footprint light detection and ranging (LiDAR) data. Attempts were made to analyze the stem volume and biomass of Korean Pine stands (Pinus koraiensis Sieb. et Zucc.) for three classes of tree density: low (240 N/ha), medium (370 N/ha), and high (1,340 N/ha). To delineate individual trees, extended maxima transformation and watershed segmentation of image processing methods were applied, as in one of our previous studies. As the next step, the crown base height (CBH) of individual trees has to be determined; information for this was found in the LiDAR point cloud data using k-means clustering. The LiDAR-derived CGV and stem volume can be estimated on the basis of the proportional relationship between the CGV and stem volume. As a result, low tree-density plots had the best performance for LiDAR-derived CBH, CGV, and stem volume (R (2) = 0.67, 0.57, and 0.68, respectively) and accuracy was lowest for high tree-density plots (R (2) = 0.48, 0.36, and 0.44, respectively). In the case of medium tree-density plots accuracy was R (2) = 0.51, 0.52, and 0.62, respectively. The LiDAR-derived stem biomass can be predicted from the stem volume using the wood basic density of coniferous trees (0.48 g/cm(3)), and the LiDAR-derived above-ground biomass can then be estimated from the stem volume using the biomass conversion and expansion factors (BCEF, 1.29) proposed by the Korea Forest Research Institute (KFRI).

  8. MRI Evaluation of Injectable Hyaluronic Acid-Based Hydrogel Therapy to Limit Ventricular Remodeling after Myocardial Infarction

    PubMed Central

    Dorsey, Shauna M.; McGarvey, Jeremy R.; Wang, Hua; Nikou, Amir; Arama, Leron; Koomalsingh, Kevin J.; Kondo, Norihiro; Gorman, Joseph H.; Pilla, James J.; Gorman, Robert C.; Wenk, Jonathan F.; Burdick, Jason A.

    2015-01-01

    Injectable biomaterials are an attractive therapy to attenuate left ventricular (LV) remodeling after myocardial infarction (MI). Although studies have shown that injectable hydrogels improve cardiac structure and function in vivo, temporal changes in infarct material properties after treatment have not been assessed. Emerging imaging and modeling techniques now allow for serial, non-invasive estimation of infarct material properties. Specifically, cine MRI assesses global LV structure and function, late-gadolinium enhancement (LGE) MRI enables visualization of infarcted tissue to quantify infarct expansion, and spatial modulation of magnetization (SPAMM) tagging provides passive wall motion assessment as a measure of tissue strain, which can all be used to evaluate infarct properties when combined with finite element (FE) models. In this work, we investigated the temporal effects of degradable hyaluronic acid (HA) hydrogels on global LV remodeling, infarct thinning and expansion, and infarct stiffness in a porcine infarct model for 12 weeks post-MI using MRI and FE modeling. Hydrogel treatment led to decreased LV volumes, improved ejection fraction, and increased wall thickness when compared to controls. FE model simulations demonstrated that hydrogel therapy increased infarct stiffness for 12 weeks post-MI. Thus, evaluation of myocardial tissue properties through MRI and FE modeling provides insight into the influence of injectable hydrogel therapies on myocardial structure and function post-MI. PMID:26280951

  9. MRI evaluation of injectable hyaluronic acid-based hydrogel therapy to limit ventricular remodeling after myocardial infarction.

    PubMed

    Dorsey, Shauna M; McGarvey, Jeremy R; Wang, Hua; Nikou, Amir; Arama, Leron; Koomalsingh, Kevin J; Kondo, Norihiro; Gorman, Joseph H; Pilla, James J; Gorman, Robert C; Wenk, Jonathan F; Burdick, Jason A

    2015-11-01

    Injectable biomaterials are an attractive therapy to attenuate left ventricular (LV) remodeling after myocardial infarction (MI). Although studies have shown that injectable hydrogels improve cardiac structure and function in vivo, temporal changes in infarct material properties after treatment have not been assessed. Emerging imaging and modeling techniques now allow for serial, non-invasive estimation of infarct material properties. Specifically, cine magnetic resonance imaging (MRI) assesses global LV structure and function, late-gadolinium enhancement (LGE) MRI enables visualization of infarcted tissue to quantify infarct expansion, and spatial modulation of magnetization (SPAMM) tagging provides passive wall motion assessment as a measure of tissue strain, which can all be used to evaluate infarct properties when combined with finite element (FE) models. In this work, we investigated the temporal effects of degradable hyaluronic acid (HA) hydrogels on global LV remodeling, infarct thinning and expansion, and infarct stiffness in a porcine infarct model for 12 weeks post-MI using MRI and FE modeling. Hydrogel treatment led to decreased LV volumes, improved ejection fraction, and increased wall thickness when compared to controls. FE model simulations demonstrated that hydrogel therapy increased infarct stiffness for 12 weeks post-MI. Thus, evaluation of myocardial tissue properties through MRI and FE modeling provides insight into the influence of injectable hydrogel therapies on myocardial structure and function post-MI.

  10. A Review of Electrical Impedance Spectrometry Methods for Parametric Estimation of Physiologic Fluid Volumes

    NASA Technical Reports Server (NTRS)

    Dewberry, B.

    2000-01-01

    Electrical impedance spectrometry involves measurement of the complex resistance of a load at multiple frequencies. With this information in the form of impedance magnitude and phase, or resistance and reactance, basic structure or function of the load can be estimated. The "load" targeted for measurement and estimation in this study consisted of the water-bearing tissues of the human calf. It was proposed and verified that by measuring the electrical impedance of the human calf and fitting this data to a model of fluid compartments, the lumped-model volume of intracellular and extracellular spaces could be estimated, By performing this estimation over time, the volume dynamics during application of stimuli which affect the direction of gravity can be viewed. The resulting data can form a basis for further modeling and verification of cardiovascular and compartmental modeling of fluid reactions to microgravity as well as countermeasures to the headward shift of fluid during head-down tilt or spaceflight.

  11. Estimating Mixed Broadleaves Forest Stand Volume Using Dsm Extracted from Digital Aerial Images

    NASA Astrophysics Data System (ADS)

    Sohrabi, H.

    2012-07-01

    In mixed old growth broadleaves of Hyrcanian forests, it is difficult to estimate stand volume at plot level by remotely sensed data while LiDar data is absent. In this paper, a new approach has been proposed and tested for estimating stand forest volume. The approach is based on this idea that forest volume can be estimated by variation of trees height at plots. In the other word, the more the height variation in plot, the more the stand volume would be expected. For testing this idea, 120 circular 0.1 ha sample plots with systematic random design has been collected in Tonekaon forest located in Hyrcanian zone. Digital surface model (DSM) measure the height values of the first surface on the ground including terrain features, trees, building etc, which provides a topographic model of the earth's surface. The DSMs have been extracted automatically from aerial UltraCamD images so that ground pixel size for extracted DSM varied from 1 to 10 m size by 1m span. DSMs were checked manually for probable errors. Corresponded to ground samples, standard deviation and range of DSM pixels have been calculated. For modeling, non-linear regression method was used. The results showed that standard deviation of plot pixels with 5 m resolution was the most appropriate data for modeling. Relative bias and RMSE of estimation was 5.8 and 49.8 percent, respectively. Comparing to other approaches for estimating stand volume based on passive remote sensing data in mixed broadleaves forests, these results are more encouraging. One big problem in this method occurs when trees canopy cover is totally closed. In this situation, the standard deviation of height is low while stand volume is high. In future studies, applying forest stratification could be studied.

  12. A voxel-based technique to estimate the volume of trees from terrestrial laser scanner data

    NASA Astrophysics Data System (ADS)

    Bienert, A.; Hess, C.; Maas, H.-G.; von Oheimb, G.

    2014-06-01

    The precise determination of the volume of standing trees is very important for ecological and economical considerations in forestry. If terrestrial laser scanner data are available, a simple approach for volume determination is given by allocating points into a voxel structure and subsequently counting the filled voxels. Generally, this method will overestimate the volume. The paper presents an improved algorithm to estimate the wood volume of trees using a voxel-based method which will correct for the overestimation. After voxel space transformation, each voxel which contains points is reduced to the volume of its surrounding bounding box. In a next step, occluded (inner stem) voxels are identified by a neighbourhood analysis sweeping in the X and Y direction of each filled voxel. Finally, the wood volume of the tree is composed by the sum of the bounding box volumes of the outer voxels and the volume of all occluded inner voxels. Scan data sets from several young Norway maple trees (Acer platanoides) were used to analyse the algorithm. Therefore, the scanned trees as well as their representing point clouds were separated in different components (stem, branches) to make a meaningful comparison. Two reference measurements were performed for validation: A direct wood volume measurement by placing the tree components into a water tank, and a frustum calculation of small trunk segments by measuring the radii along the trunk. Overall, the results show slightly underestimated volumes (-0.3% for a probe of 13 trees) with a RMSE of 11.6% for the individual tree volume calculated with the new approach.

  13. An investigation of spectral change as influenced by irrigation and evapotranspiration volume estimation in western Nebraska

    USGS Publications Warehouse

    Seevers, P.M.; Sadowski, F.C.; Lauer, D.T.

    1990-01-01

    Retrospective satellite image data were evaluated for their ability to demonstrate the influence of center-pivot irrigation development in western Nebraska on spectral change and climate-related factors for the region. Periodic images of an albedo index and a normalized difference vegetation index (NDVI) were generated from calibrated Landsat multispectral scanner (MSS) data and used to monitor spectral changes associated with irrigation development from 1972 through 1986. The albedo index was not useful for monitoring irrigation development. For the NDVI, it was found that proportions of counties in irrigated agriculture, as discriminated by a threshold, were more highly correlated with reported ground estimates of irrigated agriculture than were county mean greenness values. A similar result was achieved when using coarse resolution Advanced Very High Resolution Radiometer (AVHRR) image data for estimating irrigated agriculture. The NDVI images were used to evaluate a procedure for making areal estimates of actual evapotranspiration (ET) volumes. Estimates of ET volumes for test counties, using reported ground acreages and corresponding standard crop coefficients, were correlated with the estimates of ET volume using crop coefficients scaled to NDVI values and pixel counts of crop areas. These county estimates were made under the assumption that soil water availability was unlimited. For nonirrigated vegetation, this may result in over-estimation of ET volumes. Ground information regarding crop types and acreages are required to derive the NDVI scaling factor. Potential ET, estimated with the Jensen-Haise model, is common to both methods. These results, achieved with both MSS and AVHRR data, show promise for providing climatologically important land surface information for regional and global climate models. ?? 1990 Kluwer Academic Publishers.

  14. A comparison of estimates of statewide pleasure trip volume and expenditures derived from telephone versus mail surveys

    Treesearch

    Dae-Kwan Kim; Daniel M. Spotts; Donald F. Holecek

    1998-01-01

    This paper compares estimates of pleasure trip volume and expenditures derived from a regional telephone survey to those derived from the TravelScope mail panel survey. Significantly different estimates emerged, suggesting that survey-based estimates of pleasure trip volume and expenditures, at least in the case of the two surveys examined, appear to be affected by...

  15. 3D ultrasound estimation of the effective volume for popliteal block at the level of division.

    PubMed

    Sala-Blanch, X; Franco, J; Bergé, R; Marín, R; López, A M; Agustí, M

    2017-03-01

    Local anaesthetic injection between the tibial and commmon peroneal nerves within connective tissue sheath results in a predictable diffusion and allows for a reduction in the volume needed to achieve a consistent sciatic popliteal block. Using 3D ultrasound volumetric acquisition, we quantified the visible volume in contact with the nerve along a 5cm segment. We included 20 consecutive patients scheduled for bunion surgery. Ultrasound guided popliteal block was performed using a posterior, out of plane approach at the level of división of the sciatic nerve. Thirty ml of mepivacaine 1.5% and levobupivacaine 0.5% were slowly injected while assessing the injection pressure and the diffusion of the local anaesthetic. Volumetric acquisition was performed before and after the block to quantify the the volume of the sciatic nerve and the volume of the surrounding hypoechoic halo contained inside the connective tissue in a 5cm segment. All blocks were successful within 20min after the injection. The total estimated volume contained inside the common connective tissue sheath was 6.8±2.6cm(3). Of this, the volume of the halo sorrounding the nerve was 4.4±1.7cm(3) and the volume inside the sciatic nerve was 2.4±1.7cm(3). The volume of local anaesthetic in close contact with the sciatic nerve can be estimated by volumetric acquisition. Our results suggest that the effective volume of local anaesthetic needed for a successful sciatic popliteal block could be reduced to less than 7ml. Copyright © 2016 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  16. Simplified Volume-Area-Depth Method for Estimating Water Storage of Isolated Prairie Wetlands

    NASA Astrophysics Data System (ADS)

    Minke, A. G.; Westbrook, C. J.; van der Kamp, G.

    2009-05-01

    There are millions of wetlands in shallow depressions on the North American prairies but the quantity of water stored in these depressions remains poorly understood. Hayashi and van der Kamp (2000) used the relationship between volume (V), area (A) and depth (h) to develop an equation for estimating wetland storage. We tested the robustness of their full and simplified V-A-h methods to accurately estimate volume for the range of wetland shapes occurring across the Prairie Pothole Region. These results were contrasted with two commonly implemented V-A regression equations to determine which method estimates volume most accurately. We used detailed topographic data for 27 wetlands in Smith Creek and St. Denis watersheds, Saskatchewan that ranged in surface area and basin shape. The full V-A-h method was found to accurately estimate storage (errors <3%) across wetlands of various shapes, and is therefore suitable for calculating water storage in the variety of wetland surface shapes found in the prairies. Both V-A equations performed poorly, with volume underestimated by an average of 15% and 50% Analysis of the simplified V-A-h method showed that volume errors of <10% can be achieved if the basin and shape coefficients are derived properly. This would involve measuring depth and area twice, with sufficient time between measurements that the natural fluctuations in water storage are reflected. Practically, wetland area and depth should be measured in spring, following snowmelt when water levels are near the peak, and also in late summer prior to water depths dropping below 10 cm. These guidelines for applying the simplified V-A-h method will allow for accurate volume estimations when detailed topographic data are not available. Since the V-A equations were outperformed by the full and simplified V-A-h methods, we conclude that wetland depth and basin morphology should be considered when estimating volume. This will improve storage estimations of natural and human

  17. Determination of thigh volume in youth with anthropometry and DXA: agreement between estimates.

    PubMed

    Coelho-E-Silva, Manuel J; Malina, Robert M; Simões, Filipe; Valente-Dos-Santos, João; Martins, Raul A; Vaz Ronque, Enio R; Petroski, Edio L; Minderico, Claudia; Silva, Analiza M; Baptista, Fátima; Sardinha, Luís B

    2013-01-01

    This study examined the agreement between estimates of thigh volume (TV) with anthropometry and dual-energy x-ray absorptiometry (DXA) in healthy school children. Participants (n=168, 83 boys and 85 girls) were school children 10.0-13.9 years of age. In addition to body mass, height and sitting height, anthropometric dimensions included those needed to estimate TV using the equation of Jones & Pearson. Total TV was also estimated with DXA. Agreement between protocols was examined using linear least products regression (Deming regressions). Stepwise regression of log-transformed variables identified variables that best predicted TV estimated by DXA. The regression models were then internally validated using the predicted residual sum of squares method. Correlation between estimates of TV was 0.846 (95%CI: 0.796-0.884, Sy·x=0.152 L). It was possible to obtain an anthropometry-based model to improve the prediction of TVs in youth. The total volume by DXA was best predicted by adding body mass and sum of skinfolds to volume estimated with the equation of Jones & Pearson (R=0.972; 95%CI: 0.962-0.979; R (2)=0.945).

  18. Radar volume reflectivity estimation using an array of ground-based rainfall drop size detectors

    NASA Astrophysics Data System (ADS)

    Lane, John; Merceret, Francis; Kasparis, Takis; Roy, D.; Muller, Brad; Jones, W. Linwood

    2000-08-01

    Rainfall drop size distribution (DSD) measurements made by single disdrometers at isolated ground sites have traditionally been used to estimate the transformation between weather radar reflectivity Z and rainfall rate R. Despite the immense disparity in sampling geometries, the resulting Z-R relation obtained by these single point measurements has historically been important in the study of applied radar meteorology. Simultaneous DSD measurements made at several ground sites within a microscale area may be used to improve the estimate of radar reflectivity in the air volume surrounding the disdrometer array. By applying the equations of motion for non-interacting hydrometers, a volume estimate of Z is obtained from the array of ground based disdrometers by first calculating a 3D drop size distribution. The 3D-DSD model assumes that only gravity and terminal velocity due to atmospheric drag within the sampling volume influence hydrometer dynamics. The sampling volume is characterized by wind velocities, which are input parameters to the 3D-DSD model, composed of vertical and horizontal components. Reflectivity data from four consecutive WSR-88D volume scans, acquired during a thunderstorm near Melbourne, FL on June 1, 1997, are compared to data processed using the 3D-DSD model and data form three ground based disdrometers of a microscale array.

  19. The effect of volume conductor modeling on the estimation of cardiac vectors in fetal magnetocardiography.

    PubMed

    Tao, Rong; Popescu, Elena-Anda; Drake, William B; Jackson, David N; Popescu, Mihai

    2012-04-01

    Previous studies based on fetal magnetocardiographic (fMCG) recordings used simplified volume conductor models to estimate the fetal cardiac vector as an unequivocal measure of the cardiac source strength. However, the effect of simplified volume conductor modeling on the accuracy of the fMCG inverse solution remains largely unknown. Aiming to determine the sensitivity of the source estimators to the details of the volume conductor model, we performed simulations using fetal-maternal anatomical information from ultrasound images obtained in 20 pregnant women in various stages of pregnancy. The magnetic field produced by a cardiac source model was computed using the boundary-element method for a piecewise homogeneous volume conductor with three nested compartments (fetal body, amniotic fluid and maternal abdomen) of different electrical conductivities. For late gestation, we also considered the case of a fourth highly insulating layer of vernix caseosa covering the fetus. The errors introduced for simplified volume conductors were assessed by comparing the reconstruction results obtained with realistic versus spherically symmetric models. Our study demonstrates the significant effect of simplified volume conductor modeling, resulting mainly in an underestimation of the cardiac vector magnitude and low goodness-of-fit. These findings are confirmed by the analysis of real fMCG data recorded in mid-gestation.

  20. Estimation of the volume of the gall bladder of 32 dogs from linear ultrasonographic measurements.

    PubMed

    Atalan, G; Barr, F J; Holt, P E

    2007-01-27

    The maximum length and depth of the longitudinal section, and the maximum width and depth of the transverse section of the gall bladders of 32 dog cadavers were measured ultrasonographically; the contents of the gall bladder were then aspirated and its actual volume measured. The volume of the gall bladder was estimated from the ultrasonographic measurements by using formulae suggested for assessment of the volumes of the urinary bladder in human beings and the gall bladder of dogs, and these formulae were compared with a formula derived from the measurements made in this study. In 21 of the dogs, the measurements were repeated twice so that their reproducibility could be evaluated. All the formulae gave good estimations of the volume of the dogs' gall bladders, but the formula for the human urinary bladder volume was better than the other two. The actual volume of the gall bladder was related to the dogs' bodyweight. There were no significant differences between the repeated measurements of the maximum length and depth of the longitudinal section or the width of the transverse section of the gall bladder, but there were significant variations in the depth of the transverse section.

  1. Gas hydrate volume estimations on the South Shetland continental margin, Antarctic Peninsula

    USGS Publications Warehouse

    Jin, Y.K.; Lee, M.W.; Kim, Y.; Nam, S.H.; Kim, K.J.

    2003-01-01

    Multi-channel seismic data acquired on the South Shetland margin, northern Antarctic Peninsula, show that Bottom Simulating Reflectors (BSRs) are widespread in the area, implying large volumes of gas hydrates. In order to estimate the volume of gas hydrate in the area, interval velocities were determined using a 1-D velocity inversion method and porosities were deduced from their relationship with sub-bottom depth for terrigenous sediments. Because data such as well logs are not available, we made two baseline models for the velocities and porosities of non-gas hydrate-bearing sediments in the area, considering the velocity jump observed at the shallow sub-bottom depth due to joint contributions of gas hydrate and a shallow unconformity. The difference between the results of the two models is not significant. The parameters used to estimate the total volume of gas hydrate in the study area were 145 km of total length of BSRs identified on seismic profiles, 350 m thickness and 15 km width of gas hydrate-bearing sediments, and 6.3% of the average volume gas hydrate concentration (based on the second baseline model). Assuming that gas hydrates exist only where BSRs are observed, the total volume of gas hydrates along the seismic profiles in the area is about 4.8 ?? 1010 m3 (7.7 ?? 1012 m3 volume of methane at standard temperature and pressure).

  2. The effect of volume conductor modeling on the estimation of cardiac vectors in fetal magnetocardiography

    PubMed Central

    Tao, Rong; Popescu, Elena-Anda; Drake, William B.; Jackson, David N.; Popescu, Mihai

    2012-01-01

    Previous studies based on fetal magnetocardiographic (fMCG) recordings used simplified volume conductor models to estimate the fetal cardiac vector as an unequivocal measure of the cardiac source strength. However, the effect of simplified volume conductor modeling on the accuracy of the fMCG inverse solution remains largely unknown. Aiming to determine the sensitivity of the source estimators to the details of the volume conductor model, we performed simulations using fetal-maternal anatomical information from ultrasound images obtained in 20 pregnant women in various stages of pregnancy. The magnetic field produced by a cardiac source model was computed using the boundary element method for a piecewise homogeneous volume conductor with three nested compartments (fetal body, amniotic fluid and maternal abdomen) of different electrical conductivities. For late gestation, we also considered the case of a fourth highly insulating layer of vernix caseosa covering the fetus. The errors introduced for simplified volume conductors were assessed by comparing the reconstruction results obtained with realistic versus spherically symmetric models. Our study demonstrates a significant effect of simplified volume conductor modeling, resulting mainly in an underestimation of the cardiac vector magnitude and low goodness-of-fit. These findings are confirmed by the analysis of real fMCG data recorded in mid-gestation. PMID:22442179

  3. Guidelines for producing commercial nuclear power plant decommissioning cost estimates. Volume 2

    SciTech Connect

    Not Available

    1986-01-01

    These guidelines were prepared in response to a nuclear industry need to facilitate the preparation of cost estimates to decommission nuclear power plants. The objective of these guidelines is to enhance the credibility and thoroughness of cost estimates by providing detailed breakdown of costs to measurable, comprehensible levels in order to ensure that all estimates employing the guidelines will properly identify and account for all activities and elements of cost. These guidelines were prepared for decommissioning commercial nuclear power reactors of the pressurized water reactor and boiling water reactor types. Chapter 1 define the purpose and scope of the document and discusses the general approach, i.e., elements of decommissioning costs and cost estimating processes. A separate abstract has been prepared for each of the additional five chapters entitled: List of Decommissioning Work Activities, Unit Factor Development, Period-Dependent Cost Factors, Collateral Costs, and Cost Estimate Structure. Volume 2 contains the detailed user reference information similar to a cost estimator's notebook.

  4. Estimating volumes and costs of forest biomass in western Montana using forest inventory and geospatial data

    Treesearch

    Dan Loeffler; David E. Calkin; Robin P. Silverstein

    2006-01-01

    Utilizing timber harvest residues (biomass) for renewable energy production provides an alternative disposal method to onsite burning that may improve the economic viability of hazardous fuels treatments. Due to the relatively low value of biomass, accurate estimates of biomass volumes and costs of collection and delivery are essential if investment in renewable energy...

  5. Critical point relascope sampling for unbiased volume estimation of downed coarse woody debris

    Treesearch

    Jeffrey H. Gove; Michael S. Williams; Goran Stahl; Mark J. Ducey; Mark J. Ducey

    2005-01-01

    Critical point relascope sampling is developed and shown to be design-unbiased for the estimation of log volume when used with point relascope sampling for downed coarse woody debris. The method is closely related to critical height sampling for standing trees when trees are first sampled with a wedge prism. Three alternative protocols for determining the critical...

  6. Estimating cubic volume of small diameter tree-length logs from ponderosa and lodgepole pine.

    Treesearch

    Marlin E. Plank; James M. Cahill

    1984-01-01

    A sample of 351 ponderosa pine (Pinus ponderosa Dougl. ex Laws.) and 509 lodgepole pine (Pinus contorta Dougl. ex Loud.) logs were used to evaluate the performance of three commonly used formulas for estimating cubic volume. Smalian's formula, Bruce's formula, and Huber's formula were tested to determine which...

  7. Soil volume estimation in debris flow areas using lidar data in the 2014 Hiroshima, Japan rainstorm

    NASA Astrophysics Data System (ADS)

    Miura, H.

    2015-10-01

    Debris flows triggered by the rainstorm in Hiroshima, Japan on August 20th, 2014 produced extensive damage to the built-up areas in the northern part of Hiroshima city. In order to consider various emergency response activities and early-stage recovery planning, it is important to evaluate the distribution of the soil volumes in the debris flow areas immediately after the disaster. In this study, automated nonlinear mapping technique is applied to light detection and ranging (LiDAR)-derived digital elevation models (DEMs) observed before and after the disaster to quickly and accurately correct geometric locational errors of the data. The soil volumes generated from the debris flows are estimated by subtracting the pre- and post-event DEMs. The geomorphologic characteristics in the debris flow areas are discussed from the distribution of the estimated soil volumes.

  8. Gross-merchantable timber volume estimation using an airborne lidar system

    NASA Technical Reports Server (NTRS)

    Maclean, G. A.; Krabill, W. B.

    1986-01-01

    A preliminary study to determine the utility of an airborne laser as a tool for use by forest managers to estimate gross-merchantable timber volume was conducted near the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center, Wallops Flight Facility utilizing the NASA Airborne Oceanographic Lidar (AOL) system. Measured timber volume was regressed against the cross-sectional area of an AOL-generated profile of forest at the same location. The AOL profile area was found to be a very significant variable in the estimation of gross-merchantable timber volume. Significant improvements were obtained when the data were stratified by species. The overall R-squared value obtained was 0.921 with the regression significant at the one percent level.

  9. Cost and price estimate of Brayton and Stirling engines in selected production volumes

    NASA Technical Reports Server (NTRS)

    Fortgang, H. R.; Mayers, H. F.

    1980-01-01

    The methods used to determine the production costs and required selling price of Brayton and Stirling engines modified for use in solar power conversion units are presented. Each engine part, component and assembly was examined and evaluated to determine the costs of its material and the method of manufacture based on specific annual production volumes. Cost estimates are presented for both the Stirling and Brayton engines in annual production volumes of 1,000, 25,000, 100,000 and 400,000. At annual production volumes above 50,000 units, the costs of both engines are similar, although the Stirling engine costs are somewhat lower. It is concluded that modifications to both the Brayton and Stirling engine designs could reduce the estimated costs.

  10. Segment-specific resistivity improves body fluid volume estimates from bioimpedance spectroscopy in hemodialysis patients.

    PubMed

    Zhu, F; Kuhlmann, M K; Kaysen, G A; Sarkar, S; Kaitwatcharachai, C; Khilnani, R; Stevens, L; Leonard, E F; Wang, J; Heymsfield, S; Levin, N W

    2006-02-01

    Discrepancies in body fluid estimates between segmental bioimpedance spectroscopy (SBIS) and gold-standard methods may be due to the use of a uniform value of tissue resistivity to compute extracellular fluid volume (ECV) and intracellular fluid volume (ICV). Discrepancies may also arise from the exclusion of fluid volumes of hands, feet, neck, and head from measurements due to electrode positions. The aim of this study was to define the specific resistivity of various body segments and to use those values for computation of ECV and ICV along with a correction for unmeasured fluid volumes. Twenty-nine maintenance hemodialysis patients (16 men) underwent body composition analysis including whole body MRI, whole body potassium (40K) content, deuterium, and sodium bromide dilution, and segmental and wrist-to-ankle bioimpedance spectroscopy, all performed on the same day before a hemodialysis. Segment-specific resistivity was determined from segmental fat-free mass (FFM; by MRI), hydration status of FFM (by deuterium and sodium bromide), tissue resistance (by SBIS), and segment length. Segmental FFM was higher and extracellular hydration of FFM was lower in men compared with women. Segment-specific resistivity values for arm, trunk, and leg all differed from the uniform resistivity used in traditional SBIS algorithms. Estimates for whole body ECV, ICV, and total body water from SBIS using segmental instead of uniform resistivity values and after adjustment for unmeasured fluid volumes of the body did not differ significantly from gold-standard measures. The uniform tissue resistivity values used in traditional SBIS algorithms result in underestimation of ECV, ICV, and total body water. Use of segmental resistivity values combined with adjustment for body volumes that are neglected by traditional SBIS technique significantly improves estimations of body fluid volume in hemodialysis patients.

  11. Estimation of single cell volume from 3D confocal images using automatic data processing

    NASA Astrophysics Data System (ADS)

    Chorvatova, A.; Cagalinec, M.; Mateasik, A.; Chorvat, D., Jr.

    2012-06-01

    Cardiac cells are highly structured with a non-uniform morphology. Although precise estimation of their volume is essential for correct evaluation of hypertrophic changes of the heart, simple and unified techniques that allow determination of the single cardiomyocyte volume with sufficient precision are still limited. Here, we describe a novel approach to assess the cell volume from confocal microscopy 3D images of living cardiac myocytes. We propose a fast procedure based on segementation using active deformable contours. This technique is independent on laser gain and/or pinhole settings and it is also applicable on images of cells stained with low fluorescence markers. Presented approach is a promising new tool to investigate changes in the cell volume during normal, as well as pathological growth, as we demonstrate in the case of cell enlargement during hypertension in rats.

  12. Estimation of Stand Height and Forest Volume Using High Resolution Stereo Photography and Forest Type Map

    NASA Astrophysics Data System (ADS)

    Kim, K. M.

    2016-06-01

    Traditional field methods for measuring tree heights are often too costly and time consuming. An alternative remote sensing approach is to measure tree heights from digital stereo photographs which is more practical for forest managers and less expensive than LiDAR or synthetic aperture radar. This work proposes an estimation of stand height and forest volume(m3/ha) using normalized digital surface model (nDSM) from high resolution stereo photography (25cm resolution) and forest type map. The study area was located in Mt. Maehwa model forest in Hong Chun-Gun, South Korea. The forest type map has four attributes such as major species, age class, DBH class and crown density class by stand. Overlapping aerial photos were taken in September 2013 and digital surface model (DSM) was created by photogrammetric methods(aerial triangulation, digital image matching). Then, digital terrain model (DTM) was created by filtering DSM and subtracted DTM from DSM pixel by pixel, resulting in nDSM which represents object heights (buildings, trees, etc.). Two independent variables from nDSM were used to estimate forest stand volume: crown density (%) and stand height (m). First, crown density was calculated using canopy segmentation method considering live crown ratio. Next, stand height was produced by averaging individual tree heights in a stand using Esri's ArcGIS and the USDA Forest Service's FUSION software. Finally, stand volume was estimated and mapped using aerial photo stand volume equations by species which have two independent variables, crown density and stand height. South Korea has a historical imagery archive which can show forest change in 40 years of successful forest rehabilitation. For a future study, forest volume change map (1970s-present) will be produced using this stand volume estimation method and a historical imagery archive.

  13. New Martian valley network volume estimate consistent with ancient ocean and warm and wet climate.

    PubMed

    Luo, Wei; Cang, Xuezhi; Howard, Alan D

    2017-06-05

    The volume of Martian valley network (VN) cavity and the amount of water needed to create the cavity by erosion are of significant importance for understanding the early Martian climate, the style and rate of hydrologic cycling, and the possibility of an ancient ocean. However, previous attempts at estimating these two quantities were based on selected valleys or at local sites using crude estimates of VN length, width and depth. Here we employed an innovative progressive black top hat transformation method to estimate them on a global scale based on the depth of each valley pixel. The conservative estimate of the minimum global VN volume is 1.74 × 10(14) m(3) and minimum cumulative volume of water required is 6.86 × 10(17) m(3) (or ∼5 km of global equivalent layer, GEL). Both are much larger than previous estimates and are consistent with an early warm and wet climate with active hydrologic cycling involving an ocean.

  14. Emission computed tomography with technetium-99m pyrophosphate for delineating location and size of acute myocardial infarction in man.

    PubMed Central

    Tamaki, S; Kadota, K; Kambara, H; Suzuki, Y; Nohara, R; Murakami, T; Kawai, C; Tamaki, N; Torizuka, K

    1984-01-01

    Emission computed tomography with technetium-99m pyrophosphate was used to delineate the location and estimate the size of myocardial infarcts in 20 patients with documented acute myocardial infarction. Tomography was performed after planar imaging within 2-5 days after the onset of infarction. A series of transaxial, frontal, and sagittal tomograms were reconstructed from 32 views imaged from the left side of the patient's chest with a rotating gammacamera. Infarct volume was measured from the tomographic images by computerised planimetry and was compared with the cumulative release of creatine kinase MB isoenzyme. The planar images showed discrete myocardial uptake in 13 of the 20 patients and diffuse uptake throughout the cardiac region in the remaining seven. In contrast, the tomographic images clearly delineated discrete myocardial uptake by avoiding confusion of myocardial activity with that of surrounding structures, particularly bones, in all patients. For the 10 patients whose infarct size was assessed by analysis of the creatine kinase MB curve there was a close correlation between infarct volume estimated by tomography and by cumulative creatine kinase MB release. Thus emission computed tomography can provide a three dimensional map of technetium-99m pyrophosphate distribution within the heart and is thus able accurately to localise and estimate the size of myocardial infarcts in man. Images PMID:6331479

  15. Estimation of menstrual blood loss volume based on menstrual diary and laboratory data

    PubMed Central

    2012-01-01

    Background Abnormal uterine bleeding is often investigated in clinical studies and critical to identify during gynecological consultation. The current standard for quantification of menstrual blood loss is the alkaline-hematin-method. However, this method is expensive and inconvenient for patients. Bleeding diaries, although widely used, provide only qualitative information on menstrual blood loss. Other methods have been developed, but still do not provide reliable quantitative data. Methods We estimated blood loss volume using data from two clinical studies in women suffering abnormal menstrual bleeding. These estimations were derived from mixed linear models based on diary data, hematological parameters and age. To validate the models, we applied our results to data from a third study with a similar patient population. Results The resulting best fitting model uses diary entries on bleeding intensity at a particular day, information on occurrence and frequency of single bleeding intensities in defined time windows, hemoglobin and ferritin values and age of the patient all as predictors of menstrual blood loss volume. Sensitivity and specificity for the diagnosis of excessive bleeding were 87% and 70%, respectively. Our model-based estimates reflect the subjective assessment by physicians and patients in the same way as the measured values do. When applying the model to an independent study, we found a correlation of 0.73 between estimated and measured values for the blood loss in a single day. Further models with reduced number of parameters (simplified for easier practical use) still showed correlation values between 0.69 and 0.73. Conclusions We present a method for estimating menstrual blood loss volume in women suffering from prolonged or excessive menstrual bleeding. Our statistical model includes entries from bleeding diaries, laboratory parameters and age and produces results which correlate well with data derived by the alkaline-hematin-method. Therefore

  16. Dual-Band Radar Estimation of Stem Volume in Boreal Forest

    NASA Astrophysics Data System (ADS)

    Rauste, Yrjo; Astola, Heikki; Ahola, Heikki; Hame, Tuomas; von Poncet, Felicitas

    2010-12-01

    Forest stem volume information is needed in planning of sustainable forestry, mapping of exploitable forest resources, carbon balance studies and many other environmental applications. Radar sensors offer an efficient and weather-independent means for stem volume mapping. The radar dataset consisted of an ALOS/PALSAR dual-polarised scene from September 2008 and four TerraSAR-X spotlight scenes from February-March and July-August 2009. Ground data consisted of plot-wise data and stand-wise data. Regression models were developed with stand-wise training data where the stem volume varied between 0 and 390 m3/ha. The best 3-predictor model - 2 ALOS-PALSAR amplitudes and the phase difference between HH and VV data in a TerraSAR-X scene - produced an RMSE of 46 m3/ha (R2 = 0.7) when evaluated against stands not used in the model training. Stem volume estimation with plot-wise ground data produced lower estimation accuracies. The main reason was most likely misregistration between the opposite- looking ALOS/PALSAR and TerraSAR-X scenes, which was caused by canopy height and which was not corrected by ortho-rectification with terrain elevation model. In future work, similar look directions should be used when no canopy surface model is available for ortho-rectification. A filtering approach was developed for using the stand-wise stem-volume model in areas with no forest stand information.

  17. Forest Stand Volume Estimation Using Airborne LIDAR And Polarimetric SAR Over Hilly Region

    NASA Astrophysics Data System (ADS)

    Fan, Fengyun; Chen, Erxue; Li, Zengyuan; Liu, Qingwang; Li, Shiming; Ling, Feilong

    2010-10-01

    In order to investigate the potential capability of mapping forest stand volume using the multi-sources data, ALOS PALSAR, airborne LiDAR and high resolution CCD image in forest stand level, one test site located in the warm temperate hilly forest region of Shandong Province in China was established. Airborne LiDAR and CCD campaign was carried out in the end of May, 2005. One scene of ALOS PALSAR quad-polarization image was acquired in May 19th,2007. Ground forest plot data for Black Locust and Chinese Pine dominated forest stands were collected through field work from May to June of 2008. The correlations of forest stand volume to PALSAR backscattering coefficient of HH, HV, VH,VV, their ratio and some H-Alpha polarimetric decomposition parameters were analyzed in stand level through regression analysis. Mean forest stand volume of each polygons (forest stand) was finally estimated based on the regression model established using ground measured forest volume data and the corresponding parameters (polygon mean) derived from LiDAR CHM and polarimetric SAR data. Results show that it is feasible to combine low density LiDAR data, L-band SAR data and forest polygon data from high resolution CCD image for stand level forest volume estimation in hilly regions, the RMSE is 20.064m3/ha for Black Locust and 24.730m3/ha for Chinese Pine .

  18. Forest Stand Volume Estimation Using Airborne LIDAR And Polarimetric SAR Over Hilly Region

    NASA Astrophysics Data System (ADS)

    Fan, Fengyun; Chen, Erxue; Li, Zengyuan; Liu, Qingwang; Li, Shiming; Ling, Feilong; Pottier, Eric; Cloude, Shane

    2010-10-01

    In order to investigate the potential capability of mapping forest stand volume using the multi-sources data, ALOS PALSAR, airborne LiDAR and high resolution CCD image in forest stand level, one test site located in the warm temperate hilly forest region of Shandong Province in China was established. Airborne LiDAR and CCD campaign was carried out in the end of May, 2005. One scene of ALOS PALSAR quad-polarization image was acquired in May 19th,2007. Ground forest plot data for Black Locust and Chinese Pine dominated forest stands were collected through field work from May to June of 2008. The correlations of forest stand volume to PALSAR backscattering coefficient of HH, HV,VH,VV, their ratio and some H-Alpha polarimetric decomposition parameters were analyzed in stand level through regression analysis. Mean forest stand volume of each polygons (forest stand) was finally estimated based on the regression model established using ground measured forest volume data and the corresponding parameters (polygon mean) derived from LiDAR CHM and polarimetric SAR data. Results show that it is feasible to combine low density LiDAR data, L-band SAR data and forest polygon data from high resolution CCD image for stand level forest volume estimation in hilly regions, the RMSE is 20.064m3/ha for Black Locust and 24.730m3/ha for Chinese Pine .

  19. Bioimpedance spectroscopy for the estimation of body fluid volumes in mice.

    PubMed

    Chapman, M E; Hu, L; Plato, C F; Kohan, D E

    2010-07-01

    Conventional indicator dilution techniques for measuring body fluid volume are laborious, expensive, and highly invasive. Bioimpedance spectroscopy (BIS) may be a useful alternative due to being rapid, minimally invasive, and allowing repeated measurements. BIS has not been reported in mice; hence we examined how well BIS estimates body fluid volume in mice. Using C57/Bl6 mice, the BIS system demonstrated <5% intermouse variation in total body water (TBW) and extracellular (ECFV) and intracellular fluid volume (ICFV) between animals of similar body weight. TBW, ECFV, and ICFV differed between heavier male and lighter female mice; however, the ratio of TBW, ECFV, and ICFV to body weight did not differ between mice and corresponded closely to values in the literature. Furthermore, repeat measurements over 1 wk demonstrated <5% intramouse variation. Default resistance coefficients used by the BIS system, defined for rats, produced body composition values for TBW that exceeded body weight in mice. Therefore, body composition was measured in mice using a range of resistance coefficients. Resistance values at 10% of those defined for rats provided TBW, ECFV, and ICFV ratios to body weight that were similar to those obtained by conventional isotope dilution. Further evaluation of the sensitivity of the BIS system was determined by its ability to detect volume changes after saline infusion; saline provided the predicted changes in compartmental fluid volumes. In summary, BIS is a noninvasive and accurate method for the estimation of body composition in mice. The ability to perform serial measurements will be a useful tool for future studies.

  20. Errors in NAPL volume estimates due to systematic measurement errors during partitioning tracer tests.

    PubMed

    Brooks, Michael C; Wise, William R

    2005-09-15

    During moment-based analyses of partitioning tracer tests, systematic errors in volume and concentration measurements propagate to yield errors in the saturation and volume estimates for nonaqueous phase liquid (NAPL). Derived expressions could be applied to help practitioners bracket their estimates of NAPL saturation and volume obtained from such tests. In practice, many of these effects may be overshadowed by other complications experienced in the field. Errors are propagated for systematic constant (offset) volume, proportional volume, and constant (offset) concentration errors. Previous efforts to quantify the impact of these errors were predicated upon the specific assumption that nonpartitioning and partitioning masses were equal. The current work relaxes that assumption and is therefore more general in scope. Through the use of nondimensional concentration, systematic proportional concentration errors do not affect the accuracy of the method. Specific consideration needs to be given to accurate flow measurements and minimizing baseline concentration errors when performing partitioning tracer tests in order to prevent the propagation of systematic errors.

  1. A progressive black top hat transformation algorithm for estimating valley volumes on Mars

    NASA Astrophysics Data System (ADS)

    Luo, Wei; Pingel, Thomas; Heo, Joon; Howard, Alan; Jung, Jaehoon

    2015-02-01

    The depth of valley incision and valley volume are important parameters in understanding the geologic history of early Mars, because they are related to the amount sediments eroded and the quantity of water needed to create the valley networks (VNs). With readily available digital elevation model (DEM) data, the Black Top Hat (BTH) transformation, an image processing technique for extracting dark features on a variable background, has been applied to DEM data to extract valley depth and estimate valley volume. Previous studies typically use a single window size for extracting the valley features and a single threshold value for removing noise, resulting in finer features such as tributaries not being extracted and underestimation of valley volume. Inspired by similar algorithms used in LiDAR data analysis to remove above-ground features to obtain bare-earth topography, here we propose a progressive BTH (PBTH) transformation algorithm, where the window size is progressively increased to extract valleys of different orders. In addition, a slope factor is introduced so that the noise threshold can be automatically adjusted for windows with different sizes. Independently derived VN lines were used to select mask polygons that spatially overlap the VN lines. Volume is calculated as the sum of valley depth within the selected mask multiplied by cell area. Application of the PBTH to a simulated landform (for which the amount of erosion is known) achieved an overall relative accuracy of 96%, in comparison with only 78% for BTH. Application of PBTH to Ma'adim Vallies on Mars not only produced total volume estimates consistent with previous studies, but also revealed the detailed spatial distribution of valley depth. The highly automated PBTH algorithm shows great promise for estimating the volume of VN on Mars on global scale, which is important for understanding its early hydrologic cycle.

  2. A new graphic method for estimation of distribution volume in chronic ischemic brain lesions on I-123 IMP SPECT; in prediction of regional CBF increase by bypass surgery

    SciTech Connect

    Odano, I.; Ohkubo, M.; Takahashi, N.

    1994-05-01

    The estimate the distribution volume (Vd) of Iodine-123 IMP brain SPECT, we developed a new graphic plot, the rate constant square method, which was useful to predict an increase of rCBF in the ischemic lesions caused by bypass surgery. The tracer kinetics of IMP was assumed to be a 2-compartment model as follows: dCb(t)/dt=K1Ca(t)-k2Cb(t), where K1 is rCBF(ml/g/min), k2 is the washout constant(/min), and K1/k2 is defined as distribution volume (Vd:ml/g). When input function Ca(t) is prepared, we can determine the relationship between K1, Delayed/Early ratio and Vd on the graph. The method was applied to 13 patients with chronic cerebral infarction. Regional CBF was measured by the microsphere model and early and delayed scans were performed. In the normal area, K1 and Delayed/Early ratio were 0.5 ml/g/min and 1.0, respectively, then Vd (=31.5 ml/g) was obtained on the graph. 30.0 ml/g, the value in the infarct area was reduced. After bypass surgery undertaken on five patients, we observed a significant relationship between % increase of rCBF in the lesions and values of Vd. Since Vd reflects the extent of IMP retention in the brain tissue, we can predict an increase of rCBF by the bypass operation using this method.

  3. Tidal Volume Estimation Using the Blanket Fractal Dimension of the Tracheal Sounds Acquired by Smartphone

    PubMed Central

    Reljin, Natasa; Reyes, Bersain A.; Chon, Ki H.

    2015-01-01

    In this paper, we propose the use of blanket fractal dimension (BFD) to estimate the tidal volume from smartphone-acquired tracheal sounds. We collected tracheal sounds with a Samsung Galaxy S4 smartphone, from five (N = 5) healthy volunteers. Each volunteer performed the experiment six times; first to obtain linear and exponential fitting models, and then to fit new data onto the existing models. Thus, the total number of recordings was 30. The estimated volumes were compared to the true values, obtained with a Respitrace system, which was considered as a reference. Since Shannon entropy (SE) is frequently used as a feature in tracheal sound analyses, we estimated the tidal volume from the same sounds by using SE as well. The evaluation of the performed estimation, using BFD and SE methods, was quantified by the normalized root-mean-squared error (NRMSE). The results show that the BFD outperformed the SE (at least twice smaller NRMSE was obtained). The smallest NRMSE error of 15.877% ± 9.246% (mean ± standard deviation) was obtained with the BFD and exponential model. In addition, it was shown that the fitting curves calculated during the first day of experiments could be successfully used for at least the five following days. PMID:25923929

  4. A semi-automatic method for left ventricle volume estimate: an in vivo validation study

    NASA Technical Reports Server (NTRS)

    Corsi, C.; Lamberti, C.; Sarti, A.; Saracino, G.; Shiota, T.; Thomas, J. D.

    2001-01-01

    This study aims to the validation of the left ventricular (LV) volume estimates obtained by processing volumetric data utilizing a segmentation model based on level set technique. The validation has been performed by comparing real-time volumetric echo data (RT3DE) and magnetic resonance (MRI) data. A validation protocol has been defined. The validation protocol was applied to twenty-four estimates (range 61-467 ml) obtained from normal and pathologic subjects, which underwent both RT3DE and MRI. A statistical analysis was performed on each estimate and on clinical parameters as stroke volume (SV) and ejection fraction (EF). Assuming MRI estimates (x) as a reference, an excellent correlation was found with volume measured by utilizing the segmentation procedure (y) (y=0.89x + 13.78, r=0.98). The mean error on SV was 8 ml and the mean error on EF was 2%. This study demonstrated that the segmentation technique is reliably applicable on human hearts in clinical practice.

  5. A semi-automatic method for left ventricle volume estimate: an in vivo validation study

    NASA Technical Reports Server (NTRS)

    Corsi, C.; Lamberti, C.; Sarti, A.; Saracino, G.; Shiota, T.; Thomas, J. D.

    2001-01-01

    This study aims to the validation of the left ventricular (LV) volume estimates obtained by processing volumetric data utilizing a segmentation model based on level set technique. The validation has been performed by comparing real-time volumetric echo data (RT3DE) and magnetic resonance (MRI) data. A validation protocol has been defined. The validation protocol was applied to twenty-four estimates (range 61-467 ml) obtained from normal and pathologic subjects, which underwent both RT3DE and MRI. A statistical analysis was performed on each estimate and on clinical parameters as stroke volume (SV) and ejection fraction (EF). Assuming MRI estimates (x) as a reference, an excellent correlation was found with volume measured by utilizing the segmentation procedure (y) (y=0.89x + 13.78, r=0.98). The mean error on SV was 8 ml and the mean error on EF was 2%. This study demonstrated that the segmentation technique is reliably applicable on human hearts in clinical practice.

  6. Tidal volume estimation using the blanket fractal dimension of the tracheal sounds acquired by smartphone.

    PubMed

    Reljin, Natasa; Reyes, Bersain A; Chon, Ki H

    2015-04-27

    In this paper, we propose the use of blanket fractal dimension (BFD) to estimate the tidal volume from smartphone-acquired tracheal sounds. We collected tracheal sounds with a Samsung Galaxy S4 smartphone, from five (N = 5) healthy volunteers. Each volunteer performed the experiment six times; first to obtain linear and exponential fitting models, and then to fit new data onto the existing models. Thus, the total number of recordings was 30. The estimated volumes were compared to the true values, obtained with a Respitrace system, which was considered as a reference. Since Shannon entropy (SE) is frequently used as a feature in tracheal sound analyses, we estimated the tidal volume from the same sounds by using SE as well. The evaluation of the performed estimation, using BFD and SE methods, was quantified by the normalized root-mean-squared error (NRMSE). The results show that the BFD outperformed the SE (at least twice smaller NRMSE was obtained). The smallest NRMSE error of 15.877% ± 9.246% (mean ± standard deviation) was obtained with the BFD and exponential model. In addition, it was shown that the fitting curves calculated during the first day of experiments could be successfully used for at least the five following days.

  7. Fetal thymus volume estimation by virtual organ computer-aided analysis in normal pregnancies.

    PubMed

    Re, Claudia; Bertucci, Emma; Weissmann-Brenner, Alina; Achiron, Reuven; Mazza, Vincenzo; Gindes, Liat

    2015-05-01

    The thymus has a pyramidal shape, which is best shown in coronal planes. The aim of this study was to evaluate the potential of virtual organ computer-aided analysis to estimate fetal thymus volume in normal pregnancies. Three-dimensional volume data sets from the axial upper mediastinal section were acquired from 37 normal pregnancies between 12 and 35 weeks' gestation. Thymus volume was calculated by virtual organ computer-aided analysis by 2 separate examiners. In 12 cases, volumes were also acquired with 4-dimensional sonography and spatiotemporal image correlation software to assess the variability in thymus size between the systolic and diastolic periods of fetal heart motion. Linear regression analysis was used to assess the relationship between the fetal thymus volume and gestational age. Paired Student t tests were used to evaluate both the level of agreement for interobserver and intraobserver variability and the difference between diastolic and systolic thymus volumes. Identification of the borders of the thymus and calculation of its volume were successful in 28 patients (77.7%). Statistically significant linear growth of the thymus during pregnancy, from 12 to 35 weeks, was found. The growth coefficient for each gestational age was 0.43 (95% confidence interval, 0.355 to 0.504; P < .001). The difference in thymus size between systole and diastole was minor (0.0798 cm(3); 95% confidence interval, -0.044 to 0.203 cm(3)). Interobserver and intraobserver variability was not statistically significant. Although the thymus has a complex shape, it was possible to determine its borders and to calculate its volume by virtual organ computer-aided analysis in 77.7% of cases. Linear growth during pregnancy was found, and the minor changes during systole and diastole could be explained by condensation of the soft tissue of the thymus secondary to cardiac activity. © 2015 by the American Institute of Ultrasound in Medicine.

  8. Broad-spectrum cation channel inhibition by LOE 908 MS reduces infarct volume in vivo and postmortem in focal cerebral ischemia in the rat.

    PubMed

    Tatlisumak, T; Carano, R A; Takano, K; Meiler, M R; Li, F; Sotak, C H; Pschorn, U; Fisher, M

    2000-01-01

    Cation channels conduct calcium, sodium, and potassium, cations that are likely deleterious in the evolution of focal ischemic injury. Diffusion-weighted magnetic resonance imaging (DWI) is a powerful tool for evaluation of acute cerebral ischemia. We studied the effects of a novel, broad-spectrum inhibitor of several cation channels, LOE 908 MS, on acute ischemic lesion development with DWI and on cerebral infarct size using 2,3,5-triphenyltetrazolium chloride (TTC) staining postmortem. Eighteen male Sprague-Dawley rats underwent middle cerebral artery occlusion (MCAO) and were randomly and blindly assigned to either LOE 908 MS (1 mg/kg bolus 30 min after MCAO and continuous i.v. infusion of 10 mg/kg for 4 h thereafter) or vehicle. Whole-brain DWI was done before initiation of treatment and repeated every 30 min for the next 3.5 h. The animals were reperfused in the magnetic resonance imaging (MRI) scanner 90 min after MCAO. At 24 h, the animals were killed, and the brains were cut into six 2-mm-thick slices and stained with 2% TTC. Percent hemispheric lesion volume (%HLV) was calculated for each animal. Physiological parameters, body weight, and premature mortality (3 in the placebo group and 1 in the treated group) did not differ between the groups. No hypotension, abnormal behavior, or other adverse effects were seen. Pretreatment, the DWI-derived %HLV did not differ between the groups (19.8 +/- 6.2 in the control group and 17.9 +/- 7.9 in the treated group), whereas at 4 h after MCAO, it was significantly smaller in the treated group (21.8 +/- 15.4 vs 40.4 +/- 15.5, p = 0.03). Postmortem, TTC-derived %HLV was significantly attenuated in the LOE 908 MS group (21.3 +/- 11.9 vs 50.1 +/- 10.7, p = 0.0001) and the neurological scores at 24 h were significantly better among the treated rats (2.1 +/- 1.5 vs 4.0 +/- 1.0, p < 0.02). LOE 908 MS significantly improved neurological outcome and reduced infarct size without observable effects in rats as demonstrated in vivo

  9. Comparison of estimates of hardwood bole volume using importance sampling, the centroid method, and some taper equations

    Treesearch

    Harry V., Jr. Wiant; Michael L. Spangler; John E. Baumgras

    2002-01-01

    Various taper systems and the centroid method were compared to unbiased volume estimates made by importance sampling for 720 hardwood trees selected throughout the state of West Virginia. Only the centroid method consistently gave volumes estimates that did not differ significantly from those made by importance sampling, although some taper equations did well for most...

  10. Estimates of emergency operating capacity in US manufacturing and nonmanufacturing industries - Volume 1: Concepts and Methodology

    SciTech Connect

    Belzer, D.B. ); Serot, D.E. ); Kellogg, M.A. )

    1991-03-01

    Development of integrated mobilization preparedness policies requires planning estimates of available productive capacity during national emergency conditions. Such estimates must be developed in a manner to allow evaluation of current trends in capacity and the consideration of uncertainties in various data inputs and in engineering assumptions. This study developed estimates of emergency operating capacity (EOC) for 446 manufacturing industries at the 4-digit Standard Industrial Classification (SIC) level of aggregation and for 24 key nonmanufacturing sectors. This volume lays out the general concepts and methods used to develop the emergency operating estimates. The historical analysis of capacity extends from 1974 through 1986. Some nonmanufacturing industries are included. In addition to mining and utilities, key industries in transportation, communication, and services were analyzed. Physical capacity and efficiency of production were measured. 3 refs., 2 figs., 12 tabs. (JF)

  11. Guidelines for producing commercial nuclear power plant decommissioning cost estimates. Volume 1

    SciTech Connect

    Not Available

    1986-01-01

    These guidelines were prepared in response to a nuclear industry need to facilitate the preparation of cost estimates to decommission nuclear power plants. The objective of these guidelines is to enhance the credibility and thoroughness of cost estimates by providing detailed breakdown of costs to measurable, comprehensible levels in order to ensure that all estimates employing the guidelines will properly identify and account for all activities and elements of cost. These guidelines were prepared for decommissioning commercial nuclear power reactors of the pressurized water reactor and boiling water reactor types. Chapter 1 describes the background, objectives, and scope of the document and presents the general organization of the guidelines study. A separate abstract has been prepared for each of the thirteen additional chapters. Volume 1 contains a description of the suggested cost estimating methodology and supporting reference information.

  12. Uncertainties in peat volume and soil carbon estimated using ground penetrating radar and probing

    SciTech Connect

    Parsekian, Andrew D.; Slater, Lee; Ntarlagiannis, Dimitrios; Nolan, James; Sebestyen, Stephen D; Kolka, Randall K; Hanson, Paul J

    2012-01-01

    We evaluate the uncertainty in calculations of peat basin volume using high-resolution data . to resolve the three-dimensional structure of a peat basin using both direct (push probes) and indirect geophysical (ground penetrating radar) measurements. We compared volumetric estimates from both approaches with values from literature. We identified subsurface features that can introduce uncertainties into direct peat thickness measurements including the presence of woody peat and soft clay or gyttja. We demonstrate that a simple geophysical technique that is easily scalable to larger peatlands can be used to rapidly and cost effectively obtain more accurate and less uncertain estimates of peat basin volumes critical to improving understanding of the total terrestrial carbon pool in peatlands.

  13. Baseline estimate of the retained gas volume in Tank 241-C-106

    SciTech Connect

    Stewart, C.W.; Chen, G.

    1998-06-01

    This report presents the results of a study of the retained gas volume in Hanford Tank 241-C-106 (C-106) using the barometric pressure effect method. This estimate is required to establish the baseline conditions for sluicing the waste from C-106 into AY-102, scheduled to begin in the fall of 1998. The barometric pressure effect model is described, and the data reduction and detrending techniques are detailed. Based on the response of the waste level to the larger barometric pressure swings that occurred between October 27, 1997, and March 4, 1998, the best estimate and conservative (99% confidence) retained gas volumes in C-106 are 24 scm (840 scf) and 50 scm (1,770 scf), respectively. This is equivalent to average void fractions of 0.025 and 0.053, respectively.

  14. Advanced Transportation System Studies. Technical Area 3: Alternate Propulsion Subsystems Concepts. Volume 3; Program Cost Estimates

    NASA Technical Reports Server (NTRS)

    Levack, Daniel J. H.

    2000-01-01

    The objective of this contract was to provide definition of alternate propulsion systems for both earth-to-orbit (ETO) and in-space vehicles (upper stages and space transfer vehicles). For such propulsion systems, technical data to describe performance, weight, dimensions, etc. was provided along with programmatic information such as cost, schedule, needed facilities, etc. Advanced technology and advanced development needs were determined and provided. This volume separately presents the various program cost estimates that were generated under three tasks: the F- IA Restart Task, the J-2S Restart Task, and the SSME Upper Stage Use Task. The conclusions, technical results , and the program cost estimates are described in more detail in Volume I - Executive Summary and in individual Final Task Reports.

  15. Estimated neuronal populations and volumes of the hippocampus and its subfields in schizophrenia.

    PubMed

    Walker, Mary A; Highley, J Robin; Esiri, Margaret M; McDonald, Brendan; Roberts, Helen C; Evans, Suzanne P; Crow, Timothy J

    2002-05-01

    It has been suggested that the primary focus of the pathological process in schizophrenia is on the limbic system, and there have been several postmortem reports of changes in the histological structure or volume of the hippocampus, as well as a larger number of MRI reports of volume reductions. There are conflicting findings, however, with both techniques. The authors conducted a study of the gross and subfield structure and cellular composition of the hippocampus in postmortem brains from 30 patients with DSM-IV-diagnosed schizophrenia (13 women, 17 men) and 29 comparison subjects with no psychopathology (14 women, 15 men). Stereological sampling procedures were applied to 25-microm-thick coronal paraffin sections taken at 5-mm intervals throughout the formalin-fixed hippocampus. Subfields were defined as the dentate fascia, the hilus (CA4), an amalgamation of the CA2 and CA3 subfields, the CA1 subfield, and the subiculum. Volumes, cell densities, and cell numbers of the subfields were assessed microscopically, and the volume of the hippocampus was estimated from both photographs and histological slides of the coronal slices. As assessed from histologically stained slides, the volumes of the hippocampus and its subfields did not differ between patients and comparison subjects. Left-sided reduction in hippocampal volumes estimated from photographs, which may have included parahippocampal tissue, was not confirmed on histological examination. No significant differences were observed between patients and comparison subjects in the cellular composition of the hippocampus. These findings do not support a primary alteration of the hippocampus in schizophrenia.

  16. Monitoring and Estimation of Reservoir Water Volume using Remote Sensing and GIS

    NASA Astrophysics Data System (ADS)

    Bhat, Nagaraj; Gouda, Krushna Chandra; Vh, Manumohan; Bhat, Reshma

    2015-04-01

    Water Reservoirs are the main source of water supply for many settlements as well as power generation. So the water volume and extent of the reservoirs needs to be monitored at regular time intervals for efficient usage as well as to avoid disasters like extreme rainfall events and flood etc. Generally the reservoirs are remotely located so it is difficult to well monitor the water volume and extent. But with growing of Remote sensing and GIS in HPC environment and modeling techniques it is possible to monitor, estimate even predict the reservoir water volumes in advance by using the numerical modeling and satellite Remote sensing data. In this work the monitoring and estimation of the volume of water in the Krishna Raja Sagar(KRS) water reservoir in Karnataka state of India. In this work multispectral images from different sources like Landsat TRS and Digital Elevation Model(DEM) using IRS LISS III (IRS- Indian Remote Sensing, LISS- Linear Imaging Self-Scanning) and ASTER(Advanced Spaceborne Thermal Emission and Reflectance Radiometer) are being used .The methodology involves GIS and image processing techniques such as mosaicing and georeferencing the raw data from satellite, identifying the reservoir water level, segmentation of waterbody using the pixel level analysis. Calculating area and depth per each pixel, the total water volume calculations are done based on the empirical model developed using the past validated data. The water spreaded area calculated by using water indexing is converted in to vector polygon using ArcGIS tools. Water volume obtained by this method is compared with ground based observed values of a reservoir and the comparison well matches for 80% of cases.

  17. A Progressive Black Top Hat Transformation Algorithm for Estimating Valley Volumes from DEM Data

    NASA Astrophysics Data System (ADS)

    Luo, W.; Pingel, T.; Heo, J.; Howard, A. D.

    2013-12-01

    The amount of valley incision and valley volume are important parameters in geomorphology and hydrology research, because they are related to the amount erosion (and thus the volume of sediments) and the amount of water needed to create the valley. This is not only the case for terrestrial research but also for planetary research as such figuring out how much water was on Mars. With readily available digital elevation model (DEM) data, the Black Top Hat (BTH) transformation, an image processing technique for extracting dark features on a variable background, has been applied to DEM data to extract valley depth and estimate valley volume. However, previous studies typically use one single structuring element size for extracting the valley feature and one single threshold value for removing noise, resulting in some finer features such as tributaries not being extracted and underestimation of valley volume. Inspired by similar algorithms used in LiDAR data analysis to separate above ground features and bare earth topography, here we propose a progressive BTH (PBTH) transformation algorithm, where the structuring elements size is progressively increased to extract valleys of different orders. In addition, a slope based threshold was introduced to automatically adjust the threshold values for structuring elements with different sizes. Connectivity and shape parameters of the masked regions were used to keep the long linear valleys while removing other smaller non-connected regions. Preliminary application of the PBTH to Grand Canyon and two sites on Mars has produced promising results. More testing and fine-tuning is in progress. The ultimate goal of the project is to apply the algorithm to estimate the volume of valley networks on Mars and the volume of water needed to form the valleys we observe today and thus infer the nature of the hydrologic cycle on early Mars. The project is funded by NASA's Mars Data Analysis program.

  18. A general method for assessing the effects of uncertainty in individual-tree volume model predictions on large-area volume estimates with a subtropical forest illustration

    Treesearch

    Ronald E. McRoberts; Paolo Moser; Laio Zimermann Oliveira; Alexander C. Vibrans

    2015-01-01

    Forest inventory estimates of tree volume for large areas are typically calculated by adding the model predictions of volumes for individual trees at the plot level, calculating the mean over plots, and expressing the result on a per unit area basis. The uncertainty in the model predictions is generally ignored, with the result that the precision of the large-area...

  19. Estimation of past seepage volumes from calcite distribution in the Topopah Spring Tuff, Yucca Mountain, Nevada

    USGS Publications Warehouse

    Marshall, B.D.; Neymark, L.A.; Peterman, Z.E.

    2003-01-01

    Low-temperature calcite and opal record the past seepage of water into open fractures and lithophysal cavities in the unsaturated zone at Yucca Mountain, Nevada, site of a proposed high-level radioactive waste repository. Systematic measurements of calcite and opal coatings in the Exploratory Studies Facility (ESF) tunnel at the proposed repository horizon are used to estimate the volume of calcite at each site of calcite and/or opal deposition. By estimating the volume of water required to precipitate the measured volumes of calcite in the unsaturated zone, seepage rates of 0.005 to 5 liters/year (l/year) are calculated at the median and 95th percentile of the measured volumes, respectively. These seepage rates are at the low end of the range of seepage rates from recent performance assessment (PA) calculations, confirming the conservative nature of the performance assessment. However, the distribution of the calcite and opal coatings indicate that a much larger fraction of the potential waste packages would be contacted by this seepage than is calculated in the performance assessment.

  20. Using airborne laser altimetry to estimate Sabellaria alveolata (Polychaeta: Sabellariidae) reefs volume in tidal flat environments

    NASA Astrophysics Data System (ADS)

    Noernberg, Mauricio Almeida; Fournier, Jérôme; Dubois, Stanislas; Populus, Jacques

    2010-12-01

    This study has exploited aerial photographs and LiDAR digital elevation model to quantify intertidal complex landforms volume. A first volume estimation of the main sabellariid polychaete reef complex of the Bay of Mont-Saint-Michel - France is presented. The Sabellaria alveolata is an engineering species that heavily modifies its environment. This gregarious tube-building annelid forms dense and solid reefs of bioclastic coarse sand which can reach several km 2. Since 1970 a very strong decline of reefs has been observed. The authorities have curbed fishing activities without any noticeable changes in reef health status. The S. alveolata reef volume is estimated to be 132 048 m 3 (96 301 m 3 for Sainte-Anne reef and 35 747 m 3 for Champeaux reef). Further LiDAR data surveys will be needed to be able to understand and quantify the accretion/erosion processes in play in the reef dynamic. Because of the internal variability of topographic complexity of the reef, characterized by crevices, cracks, and holes rather than whole blocks, further studies are needed to calculate more accurately the volume of the reef.

  1. Estimation of past seepage volumes from calcite distribution in the Topopah Spring Tuff, Yucca Mountain, Nevada.

    PubMed

    Marshall, Brian D; Neymark, Leonid A; Peterman, Zell E

    2003-01-01

    Low-temperature calcite and opal record the past seepage of water into open fractures and lithophysal cavities in the unsaturated zone at Yucca Mountain, Nevada, site of a proposed high-level radioactive waste repository. Systematic measurements of calcite and opal coatings in the Exploratory Studies Facility (ESF) tunnel at the proposed repository horizon are used to estimate the volume of calcite at each site of calcite and/or opal deposition. By estimating the volume of water required to precipitate the measured volumes of calcite in the unsaturated zone, seepage rates of 0.005 to 5 liters/year (l/year) are calculated at the median and 95th percentile of the measured volumes, respectively. These seepage rates are at the low end of the range of seepage rates from recent performance assessment (PA) calculations, confirming the conservative nature of the performance assessment. However, the distribution of the calcite and opal coatings indicate that a much larger fraction of the potential waste packages would be contacted by this seepage than is calculated in the performance assessment.

  2. Volume and Mass Estimation of Three-Phase High Power Transformers for Space Applications

    NASA Technical Reports Server (NTRS)

    Kimnach, Greg L.

    2004-01-01

    Spacecraft historically have had sub-1kW(sub e), electrical requirements for GN&C, science, and communications: Galileo at 600W(sub e), and Cassini at 900W(sub e), for example. Because most missions have had the same order of magnitude power requirements, the Power Distribution Systems (PDS) use existing, space-qualified technology and are DC. As science payload and mission duration requirements increase, however, the required electrical power increases. Subsequently, this requires a change from a passive energy conversion (solar arrays and batteries) to dynamic (alternator, solar dynamic, etc.), because dynamic conversion has higher thermal and conversion efficiencies, has higher power densities, and scales more readily to higher power levels. Furthermore, increased power requirements and physical distribution lengths are best served with high-voltage, multi-phase AC to maintain distribution efficiency and minimize voltage drops. The generated AC-voltage must be stepped-up (or down) to interface with various subsystems or electrical hardware. Part of the trade-space design for AC distribution systems is volume and mass estimation of high-power transformers. The volume and mass are functions of the power rating, operating frequency, the ambient and allowable temperature rise, the types and amount of heat transfer available, the core material and shape, the required flux density in a core, the maximum current density, etc. McLyman has tabulated the performance of a number of transformers cores and derived a "cookbook" methodology to determine the volume of transformers, whereas Schawrze had derived an empirical method to estimate the mass of single-phase transformers. Based on the work of McLyman and Schwarze, it is the intent herein to derive an empirical solution to the volume and mass estimation of three-phase, laminated EI-core power transformers, having radiated and conducted heat transfer mechanisms available. Estimation of the mounting hardware, connectors

  3. Estimation of the standard molal heat capacities, entropies and volumes of 2:1 clay minerals

    NASA Astrophysics Data System (ADS)

    Ransom, Barbara; Helgeson, Harold C.

    1994-11-01

    The dearth of accurate values of the thermodynamic properties of 2:1 clay minerals severely hampers interpretation of their phase relations, the design of critical laboratory experiments and geologically realistic computer calculations of mass transfer in weathering, diagenetic and hydrothermal systems. Algorithms and strategies are described below for estimating to within 2% the standard molal heat capacities, entropies, and volumes of illites, smectites and other 2:1 clay minerals. These techniques can also be used to estimate standard molal thermodynamic properties of fictive endmembers of clay mineral solid solutions. Because 2:1 clay minerals like smectite and vermiculite are always hydrated to some extent in nature, contribution of interlayer H 2O to their thermodynamic properties is considered explicitly in the estimation of the standard molal heat capacities, entropies, and volumes of these minerals. Owing to the lack of accurate calorimetric data from which reliable values of the standard molal heat capacity and entropy of interlayer H 2O can be retrieved, these properties were taken in a first approximation to be equal to those of zeolitic H 2O in analcite. The resulting thermodynamic contributions per mole of interlayer H 2O to the standard molal heat capacity, entropy, and volume of hydrous clay minerals at 1 bar and 25°C are 11.46 cal mol -1, 13.15 cal mol -1 K -1 and 17.22 cm 3 mol, respectively. Estimated standard molal heat capacities, entropies and volumes are given for a suite of smectites and illites commonly used in models of clay mineral and shale diagenesis.

  4. Profiling river surface velocities and volume flow estimation with bistatic UHF RiverSonde radar

    USGS Publications Warehouse

    Barrick, D.; Teague, C.; Lilleboe, P.; Cheng, R.; Gartner, J.; ,

    2003-01-01

    From the velocity profiles across the river, estimates of total volume flow for the four methods were calculated based on a knowledge of the bottom depth vs position across the river. It was found that the flow comparisons for the American River were much closer, within 2% of each other among all of the methods. Sources of positional biases and anomalies in the RiverSonde measurement patterns along the river were identified and discussed.

  5. ICESat Estimates of Elevation and Volume Changes of Greenland Ice Caps

    NASA Astrophysics Data System (ADS)

    Robbins, J. W.; Zwally, J.; Yi, D.; Li, J.; Saba, J. L.

    2012-12-01

    ICESat Laser Altimetry acquired over the period 2003-2008 has been processed to provide estimates of changes in elevation for each aligned laser footprint. These are then interpolated, geographically, yielding estimates of volume change on nearly two dozen peripheral ice caps, mostly located in northern Greenland. Definition of ice cap edges are provided by the Greenland Mapping Project 90m, high-resolution, ice mask (GIMP). The results provide a geometric measure of sub-decadal ice cap gain or loss, with the outcome being that more ice caps are losing volume than gaining. Ice caps ranging in size from 200 to 7500 square km have been considered. Over the five-years, ice cap volume changes range from -1.586 cubic km for the Ikke Opmålt cap (2965.1 sq. km areal extent) to +0.582 cubic km on the Kronprins Christian Land cap (7414.6 sq. km). The corresponding averaged rates of elevation change range from -0.535 m/yr to +0.079 m/yr, respectively. Estimates of elevation changes from variations in the rate of firn compaction are also applied. Additionally, examination of time histories of ICESat elevation profiles crossing select ice caps reveal seasonal losses and gains.

  6. Validating methods for estimating endocranial volume in individual red deer (Cervus elaphus).

    PubMed

    Logan, Corina J; Clutton-Brock, Tim H

    2013-01-01

    Comparing brain sizes is a key method in comparative cognition and evolution. Brain sizes are commonly validated by interspecific comparisons involving animals of varying size, which does not provide a realistic index of their accuracy for intraspecific comparisons. Intraspecific validation of methods for measuring brain size should include animals of the same age and sex to ensure that individual differences can be detected in animals of similar size. In this study we compare three methods of measuring the endocranial volume of 33 red deer skulls to investigate the accuracy of each method. Methods for estimating endocranial volume included scanning each skull using computerised tomography (CT) and quantifying the volume with OsiriX software, filling the cranium with glass beads and measuring the bead volume, and linear measurements (length, width, and height) of the cranium using callipers. CT scan volumes were highly correlated with results from the bead method, but only moderately correlated with the linear method. This study illustrates the importance of validating intraspecies measurement methods, which allows for the accurate interpretation of results. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. An optimized method for estimating the tidal volume from intracardiac or body surface electrocardiographic signals: implications for estimating minute ventilation

    PubMed Central

    Sayadi, Omid; Weiss, Eric H.; Merchant, Faisal M.; Puppala, Dheeraj

    2014-01-01

    The ability to accurately monitor tidal volume (TV) from electrocardiographic (ECG) signals holds significant promise for improving diagnosis treatment across a variety of clinical settings. The objective of this study was to develop a novel method for estimating the TV from ECG signals. In 10 mechanically ventilated swine, we collected intracardiac electrograms from catheters in the coronary sinus (CS), left ventricle (LV), and right ventricle (RV), as well as body surface electrograms, while TV was varied between 0 and 750 ml at respiratory rates of 7–14 breaths/min. We devised an algorithm to determine the optimized respirophasic modulation of the amplitude of the ECG-derived respiratory signal. Instantaneous measurement of respiratory modulation showed an absolute error of 72.55, 147.46, 85.68, 116.62, and 50.89 ml for body surface, CS, LV, RV, and RV-CS leads, respectively. Minute TV estimation demonstrated a more accurate estimation with an absolute error of 69.56, 153.39, 79.33, 122.16, and 48.41 ml for body surface, CS, LV, RV, and RV-CS leads, respectively. The RV-CS and body surface leads provided the most accurate estimations that were within 7 and 10% of the true TV, respectively. Finally, the absolute error of the bipolar RV-CS lead was significantly lower than any other lead configuration (P < 0.0001). In conclusion, we have demonstrated that ECG-derived respiratory modulation provides an accurate estimation of the TV using intracardiac or body surface signals, without the need for additional hardware. PMID:24906917

  8. Generating human reliability estimates using expert judgment. Volume 1. Main report

    SciTech Connect

    Comer, M.K.; Seaver, D.A.; Stillwell, W.G.; Gaddy, C.D.

    1984-11-01

    The US Nuclear Regulatory Commission is conducting a research program to determine the practicality, acceptability, and usefulness of several different methods for obtaining human reliability data and estimates that can be used in nuclear power plant probabilistic risk assessment (PRA). One method, investigated as part of this overall research program, uses expert judgment to generate human error probability (HEP) estimates and associated uncertainty bounds. The project described in this document evaluated two techniques for using expert judgment: paired comparisons and direct numerical estimation. Volume 1 of this report provides a brief overview of the background of the project, the procedure for using psychological scaling techniques to generate HEP estimates and conclusions from evaluation of the techniques. Results of the evaluation indicate that techniques using expert judgment should be given strong consideration for use in developing HEP estimates. In addition, HEP estimates for 35 tasks related to boiling water reactors (BMRs) were obtained as part of the evaluation. These HEP estimates are also included in the report.

  9. A practical guideline for intracranial volume estimation in patients with Alzheimer's disease

    PubMed Central

    2015-01-01

    Background Intracranial volume (ICV) is an important normalization measure used in morphometric analyses to correct for head size in studies of Alzheimer Disease (AD). Inaccurate ICV estimation could introduce bias in the outcome. The current study provides a decision aid in defining protocols for ICV estimation in patients with Alzheimer disease in terms of sampling frequencies that can be optimally used on the volumetric MRI data, and the type of software most suitable for use in estimating the ICV measure. Methods Two groups of 22 subjects are considered, including adult controls (AC) and patients with Alzheimer Disease (AD). Reference measurements were calculated for each subject by manually tracing intracranial cavity by the means of visual inspection. The reliability of reference measurements were assured through intra- and inter- variation analyses. Three publicly well-known software packages (Freesurfer, FSL, and SPM) were examined in their ability to automatically estimate ICV across the groups. Results Analysis of the results supported the significant effect of estimation method, gender, cognitive condition of the subject and the interaction among method and cognitive condition factors in the measured ICV. Results on sub-sampling studies with a 95% confidence showed that in order to keep the accuracy of the interleaved slice sampling protocol above 99%, the sampling period cannot exceed 20 millimeters for AC and 15 millimeters for AD. Freesurfer showed promising estimates for both adult groups. However SPM showed more consistency in its ICV estimation over the different phases of the study. Conclusions This study emphasized the importance in selecting the appropriate protocol, the choice of the sampling period in the manual estimation of ICV and selection of suitable software for the automated estimation of ICV. The current study serves as an initial framework for establishing an appropriate protocol in both manual and automatic ICV estimations with

  10. A practical guideline for intracranial volume estimation in patients with Alzheimer's disease.

    PubMed

    Sargolzaei, Saman; Sargolzaei, Arman; Cabrerizo, Mercedes; Chen, Gang; Goryawala, Mohammed; Noei, Shirin; Zhou, Qi; Duara, Ranjan; Barker, Warren; Adjouadi, Malek

    2015-01-01

    Intracranial volume (ICV) is an important normalization measure used in morphometric analyses to correct for head size in studies of Alzheimer Disease (AD). Inaccurate ICV estimation could introduce bias in the outcome. The current study provides a decision aid in defining protocols for ICV estimation in patients with Alzheimer disease in terms of sampling frequencies that can be optimally used on the volumetric MRI data, and the type of software most suitable for use in estimating the ICV measure. Two groups of 22 subjects are considered, including adult controls (AC) and patients with Alzheimer Disease (AD). Reference measurements were calculated for each subject by manually tracing intracranial cavity by the means of visual inspection. The reliability of reference measurements were assured through intra- and inter- variation analyses. Three publicly well-known software packages (Freesurfer, FSL, and SPM) were examined in their ability to automatically estimate ICV across the groups. Analysis of the results supported the significant effect of estimation method, gender, cognitive condition of the subject and the interaction among method and cognitive condition factors in the measured ICV. Results on sub-sampling studies with a 95% confidence showed that in order to keep the accuracy of the interleaved slice sampling protocol above 99%, the sampling period cannot exceed 20 millimeters for AC and 15 millimeters for AD. Freesurfer showed promising estimates for both adult groups. However SPM showed more consistency in its ICV estimation over the different phases of the study. This study emphasized the importance in selecting the appropriate protocol, the choice of the sampling period in the manual estimation of ICV and selection of suitable software for the automated estimation of ICV. The current study serves as an initial framework for establishing an appropriate protocol in both manual and automatic ICV estimations with different subject populations.

  11. Volume estimation using food specific shape templates in mobile image-based dietary assessment

    NASA Astrophysics Data System (ADS)

    Chae, Junghoon; Woo, Insoo; Kim, SungYe; Maciejewski, Ross; Zhu, Fengqing; Delp, Edward J.; Boushey, Carol J.; Ebert, David S.

    2011-03-01

    As obesity concerns mount, dietary assessment methods for prevention and intervention are being developed. These methods include recording, cataloging and analyzing daily dietary records to monitor energy and nutrient intakes. Given the ubiquity of mobile devices with built-in cameras, one possible means of improving dietary assessment is through photographing foods and inputting these images into a system that can determine the nutrient content of foods in the images. One of the critical issues in such the image-based dietary assessment tool is the accurate and consistent estimation of food portion sizes. The objective of our study is to automatically estimate food volumes through the use of food specific shape templates. In our system, users capture food images using a mobile phone camera. Based on information (i.e., food name and code) determined through food segmentation and classification of the food images, our system choose a particular food template shape corresponding to each segmented food. Finally, our system reconstructs the three-dimensional properties of the food shape from a single image by extracting feature points in order to size the food shape template. By employing this template-based approach, our system automatically estimates food portion size, providing a consistent method for estimation food volume.

  12. Simulation method for cardiac stroke volume estimation by intracardiac electrical impedance measurement.

    PubMed

    Barak, C; Leviatan, Y; Inbar, G F; Hoekstein, K N

    1992-09-01

    Using the electrical impedance measurement technique to investigate stroke volume estimation, three models of the ventricle were simulated. A four-electrode impedance catheter was used; two electrodes to set up an electric field in the model and the other two to measure the potential difference. A new approach, itself an application of the quasi-static case of a method used to solve electromagnetic field problems, was used to solve the electric field in the model. The behaviour of the estimation is examined with respect to the electrode configuration on the catheter and to catheter location with respect to the ventricle walls. Cardiac stroke volume estimation was found to be robust to catheter location generating a 10 per cent error for an offset of 40 per cent of the catheter from the chamber axis and rotation of 20 degrees with respect to the axis. The electrode configuration has a dominant effect on the sensitivity and accuracy of the estimation. Certain configurations gave high accuracy, whereas in others high sensitivity was found with lower accuracy. This led to the conclusion that the electrode configuration should be carefully chosen according to the desired criteria.

  13. Estimating increased electronic laboratory reporting volumes for meaningful use: 
implications for the public health workforce.

    PubMed

    Dixon, Brian E; Gibson, P Joseph; Grannis, Shaun J

    2014-01-01

    To provide formulas for estimating notifiable disease reporting volume from 'meaningful use' electronic laboratory reporting (ELR). We analyzed two years of comprehensive ELR reporting data from 15 metropolitan hospitals and laboratories. Report volumes were divided by population counts to derive generalizable estimators. Observed volume of notifiable disease reports in a metropolitan area were more than twice national averages. ELR volumes varied by institution type, bed count, and by the level of effort required of health department staff. Health departments may experience a significant increase in notifiable disease reporting following efforts to fulfill meaningful use requirements, resulting in increases in workload that may further strain public health resources. Volume estimators provide a method for predicting ELR transaction volumes, which may support administrative planning in health departments.

  14. ICPP calcined solids storage facility closure study. Volume II: Cost estimates, planning schedules, yearly cost flowcharts, and life-cycle cost estimates

    SciTech Connect

    1998-02-01

    This document contains Volume II of the Closure Study for the Idaho Chemical Processing Plant Calcined Solids Storage Facility. This volume contains draft information on cost estimates, planning schedules, yearly cost flowcharts, and life-cycle costs for the four options described in Volume I: (1) Risk-Based Clean Closure; NRC Class C fill, (2) Risk-Based Clean Closure; Clean fill, (3) Closure to landfill Standards; NRC Class C fill, and (4) Closure to Landfill Standards; Clean fill.

  15. A volume law for specification of linear channel storage for estimation of large floods

    NASA Astrophysics Data System (ADS)

    Zhang, Shangyou; Cordery, Ian; Sharma, Ashish

    2000-02-01

    A method of estimating large floods using a linear storage-routing approach is presented. The differences between the proposed approach and those traditionally used are (1) that the flood producing properties of basins are represented by a linear system, (2) the storage parameters of the distributed model are determined using a volume law which, unlike other storage-routing models, accounts for the distribution of storage in natural basins, and (3) the basin outflow hydrograph is determined analytically and expressed in a succinct mathematical form. The single model parameter is estimated from observed data without direct fitting, unlike most traditionally used methods. The model was tested by showing it could reproduce observed large floods on a number of basins. This paper compares the proposed approach with a traditionally used storage routing approach using observed flood data from the Hacking River basin in New South Wales, Australia. Results confirm the usefulness of the proposed approach for estimation of large floods.

  16. Main Trend Extraction Based on Irregular Sampling Estimation and Its Application in Storage Volume of Internet Data Center.

    PubMed

    Miao, Beibei; Dou, Chao; Jin, Xuebo

    2016-01-01

    The storage volume of internet data center is one of the classical time series. It is very valuable to predict the storage volume of a data center for the business value. However, the storage volume series from a data center is always "dirty," which contains the noise, missing data, and outliers, so it is necessary to extract the main trend of storage volume series for the future prediction processing. In this paper, we propose an irregular sampling estimation method to extract the main trend of the time series, in which the Kalman filter is used to remove the "dirty" data; then the cubic spline interpolation and average method are used to reconstruct the main trend. The developed method is applied in the storage volume series of internet data center. The experiment results show that the developed method can estimate the main trend of storage volume series accurately and make great contribution to predict the future volume value. 
.

  17. Estimation of respiratory volume from thoracoabdominal breathing distances: comparison of two models of machine learning.

    PubMed

    Dumond, Rémy; Gastinger, Steven; Rahman, Hala Abdul; Faucheur, Alexis Le; Quinton, Patrice; Kang, Haitao; Prioux, Jacques

    2017-08-01

    The purposes of this study were to both improve the accuracy of respiratory volume (V) estimates using the respiratory magnetometer plethysmography (RMP) technique and facilitate the use of this technique. We compared two models of machine learning (ML) for estimating [Formula: see text]: a linear model (multiple linear regression-MLR) and a nonlinear model (artificial neural network-ANN), and we used cross-validation to validate these models. Fourteen healthy adults, aged [Formula: see text] years participated in the present study. The protocol was conducted in a laboratory test room. The anteroposterior displacements of the rib cage and abdomen, and the axial displacements of the chest wall and spine were measured using two pairs of magnetometers. [Formula: see text] was estimated from these four signals, and the respiratory volume was simultaneously measured using a spirometer ([Formula: see text]) under lying, sitting and standing conditions as well as various exercise conditions (working on computer, treadmill walking at 4 and 6 km[Formula: see text], treadmill running at 9 and 12  km [Formula: see text] and ergometer cycling at 90 and 110 W). The results from the ANN model fitted the spirometer volume significantly better than those obtained through MLR. Considering all activities, the difference between [Formula: see text] and [Formula: see text] (bias) was higher for the MLR model ([Formula: see text] L) than for the ANN model ([Formula: see text] L). Our results demonstrate that this new processing approach for RMP seems to be a valid tool for estimating V with sufficient accuracy during lying, sitting and standing and under various exercise conditions.

  18. Urinary neutrophil gelatinase-associated lipocalin and cystatin C compared to the estimated glomerular filtration rate to predict risk in patients with suspected acute myocardial infarction.

    PubMed

    von Jeinsen, Beatrice; Kraus, Daniel; Palapies, Lars; Tzikas, Stergios; Zeller, Tanja; Schauer, Anne; Drechsler, Christiane; Bickel, Christoph; Baldus, Stephan; Lackner, Karl J; Münzel, Thomas; Blankenberg, Stefan; Zeiher, Andreas M; Keller, Till

    2017-10-15

    Impaired renal function, reflected by estimated glomerular filtration rate (eGFR) or cystatin C, is a strong risk predictor in the presence of acute myocardial infarction (AMI). Urinary neutrophil gelatinase-associated lipocalin (uNGAL) is an early marker of acute kidney injury. uNGAL might also be a good predictor of outcome in patients with cardiovascular disease. Aim of the present study was to evaluate the prognostic value of uNGAL compared to eGFR and cystatin C in patients with suspected AMI. 1818 patients were enrolled with suspected AMI. Follow-up information on the combined endpoint of death or non-fatal myocardial infarction was obtained 6months after enrolment and was available in 1804 patients. 63 events (3.5%) were registered. While cystatin C and eGFR were strong risk predictors for the primary endpoint even adjusted for several variables, uNGAL was not independently associated with outcome: When applied continuously uNGAL was associated with outcome but did not remain a statistically significant predictor after several adjustments (i.e. eGFR). By adding cystatin C or uNGAL to GRACE risk score variables, only cystatin C could improve the predictive value while uNGAL showed no improvement. We could show that cystatin C is an independent risk predictor in patients with suspected AMI and cystatin C can add improvement to the commonly used GRACE risk score. In contrast uNGAL is not independently associated with outcome and seems not to add further prognostic information to GRACE risk score. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Robust estimation of simulated urinary volume from camera images under bathroom illumination.

    PubMed

    Honda, Chizuru; Bhuiyan, Md Shoaib; Kawanaka, Haruki; Watanabe, Eiichi; Oguri, Koji

    2016-08-01

    General uroflowmetry method involves the risk of nosocomial infections or time and effort of the recording. Medical institutions, therefore, need to measure voided volume simply and hygienically. Multiple cylindrical model that can estimate the fluid flow rate from the photographed image using camera has been proposed in an earlier study. This study implemented a flow rate estimation by using a general-purpose camera system (Raspberry Pi Camera Module) and the multiple cylindrical model. However, large amounts of noise in extracting liquid region are generated by the variation of the illumination when performing measurements in the bathroom. So the estimation error gets very large. In other words, the specifications of the previous study's camera setup regarding the shutter type and the frame rate was too strict. In this study, we relax the specifications to achieve a flow rate estimation using a general-purpose camera. In order to determine the appropriate approximate curve, we propose a binarizing method using background subtraction at each scanning row and a curve approximation method using RANSAC. Finally, by evaluating the estimation accuracy of our experiment and by comparing it with the earlier study's results, we show the effectiveness of our proposed method for flow rate estimation.

  20. Tumor Volume Estimation and Quasi-Continuous Administration for Most Effective Bevacizumab Therapy

    PubMed Central

    Sápi, Johanna; Kovács, Levente; Drexler, Dániel András; Kocsis, Pál; Gajári, Dávid; Sápi, Zoltán

    2015-01-01

    Background Bevacizumab is an exogenous inhibitor which inhibits the biological activity of human VEGF. Several studies have investigated the effectiveness of bevacizumab therapy according to different cancer types but these days there is an intense debate on its utility. We have investigated different methods to find the best tumor volume estimation since it creates the possibility for precise and effective drug administration with a much lower dose than in the protocol. Materials and Methods We have examined C38 mouse colon adenocarcinoma and HT-29 human colorectal adenocarcinoma. In both cases, three groups were compared in the experiments. The first group did not receive therapy, the second group received one 200 μg bevacizumab dose for a treatment period (protocol-based therapy), and the third group received 1.1 μg bevacizumab every day (quasi-continuous therapy). Tumor volume measurement was performed by digital caliper and small animal MRI. The mathematical relationship between MRI-measured tumor volume and mass was investigated to estimate accurate tumor volume using caliper-measured data. A two-dimensional mathematical model was applied for tumor volume evaluation, and tumor- and therapy-specific constants were calculated for the three different groups. The effectiveness of bevacizumab administration was examined by statistical analysis. Results In the case of C38 adenocarcinoma, protocol-based treatment did not result in significantly smaller tumor volume compared to the no treatment group; however, there was a significant difference between untreated mice and mice who received quasi-continuous therapy (p = 0.002). In the case of HT-29 adenocarcinoma, the daily treatment with one-twelfth total dose resulted in significantly smaller tumors than the protocol-based treatment (p = 0.038). When the tumor has a symmetrical, solid closed shape (typically without treatment), volume can be evaluated accurately from caliper-measured data with the applied two

  1. A statistical method to estimate outflow volume in case of levee breach due to overtopping

    NASA Astrophysics Data System (ADS)

    Brandimarte, Luigia; Martina, Mario; Dottori, Francesco; Mazzoleni, Maurizio

    2015-04-01

    The aim of this study is to propose a statistical method to assess the outflowing water volume through a levee breach, due to overtopping, in case of three different types of grass cover quality. The first step in the proposed methodology is the definition of the reliability function, a the relation between loading and resistance conditions on the levee system, in case of overtopping. Secondly, the fragility curve, which relates the probability of failure with loading condition over the levee system, is estimated having defined the stochastic variables in the reliability function. Thus, different fragility curves are assessed in case of different scenarios of grass cover quality. Then, a levee breach model is implemented and combined with a 1D hydrodynamic model in order to assess the outflow hydrograph given the water level in the main channel and stochastic values of the breach width. Finally, the water volume is estimated as a combination of the probability density function of the breach width and levee failure. The case study is located in the in 98km-braided reach of Po River, Italy, between the cross-sections of Cremona and Borgoforte. The analysis showed how different counter measures, different grass cover quality in this case, can reduce the probability of failure of the levee system. In particular, for a given values of breach width good levee cover qualities can significantly reduce the outflowing water volume, compared to bad cover qualities, inducing a consequent lower flood risk within the flood-prone area.

  2. Recovery of metal oxides from fly ash. Volume 2. Engineering data and cost estimates. Final report

    SciTech Connect

    Wilder, R.F.; Barrett, P.J.; Henslee, L.W. Jr.

    1984-06-01

    An engineering, cost and financial evaluation study was carried out for a conceptual commercial plant to process fly ash into marketable metal oxides by the direct HCl acid leach process. The proposed plant site was adjacent to the TVA Kingston, Tennessee power plant and was sized to process 1 million tons of ash (dry basis) per year. The capital cost requirements for the HCl direct acid leach (DAL) optimized process plant were estimated to be $244,390,000. Based upon the reported Kingston plant fly ash analysis and extractability, the conceptual commercial plant would annually produce about 158,000 TPY of alumina, 102,000 TPY of ferric oxide, 46,000 TPY of gypsum, 81,000 TPY of alkali sulfate salts, 866,000 TPY of spent fly ash and 1,940,000 kWh of excess cogeneration power. Potential long term average revenues were projected to be $126,400,000 per year which would indicate a commercial project's economics may be quite adequate. Volume 1 of this study report presents the investment and operating cost data, revenue considerations and an evaluation of profitability. Volume 2 presents the engineering data and capital cost estimates and Volume 3 presents the commercial facility design criteria. 16 references, 3 figures, 2 tables.

  3. Automatic Thickness and Volume Estimation of Sprayed Concrete on Anchored Retaining Walls from Terrestrial LIDAR Data

    NASA Astrophysics Data System (ADS)

    Martínez-Sánchez, J.; Puente, I.; GonzálezJorge, H.; Riveiro, B.; Arias, P.

    2016-06-01

    When ground conditions are weak, particularly in free formed tunnel linings or retaining walls, sprayed concrete can be applied on the exposed surfaces immediately after excavation for shotcreting rock outcrops. In these situations, shotcrete is normally applied conjointly with rock bolts and mesh, thereby supporting the loose material that causes many of the small ground falls. On the other hand, contractors want to determine the thickness and volume of sprayed concrete for both technical and economic reasons: to guarantee their structural strength but also, to not deliver excess material that they will not be paid for. In this paper, we first introduce a terrestrial LiDAR-based method for the automatic detection of rock bolts, as typically used in anchored retaining walls. These ground support elements are segmented based on their geometry and they will serve as control points for the co-registration of two successive scans, before and after shotcreting. Then we compare both point clouds to estimate the sprayed concrete thickness and the expending volume on the wall. This novel methodology is demonstrated on repeated scan data from a retaining wall in the city of Vigo (Spain), resulting in a rock bolts detection rate of 91%, that permits to obtain a detailed information of the thickness and calculate a total volume of 3597 litres of concrete. These results have verified the effectiveness of the developed approach by increasing productivity and improving previous empirical proposals for real time thickness estimation.

  4. Accuracy estimation for projection-to-volume targeting during rotational therapy: a feasibility study.

    PubMed

    Long, Yong; Fessler, Jeffrey A; Balter, James M

    2010-06-01

    Estimating motion and deformation parameters from a series of projection radiographs acquired during arc therapy using a reference CT volume has become a promising technique for targeting treatment. The purpose of this work is to investigate the influence of rotational arc length on maximum achievable accuracy of motion estimation. The projection-to-volume alignment procedure used a nonrigid model to describe motion in thorax area, a cost function consisting of a least-squared error metric and a simple regularizer that encourages local invertibility, and a four-level multiresolution scheme with a conjugate gradient method to optimize the cost function. The authors tested both small and large scale deformations typically found in the thorax of a radiotherapy patient at different breathing states and limited-angle scans of six angular widths (12 degrees, 18 degrees, 24 degrees, 36 degrees, 60 degrees, and 90 degrees) centered at three angles (0 degrees, 45 degrees, and 90 degrees). The experiments illustrate the potential accuracy of limited-angle projection-to-volume alignment. Registration accuracy can be sensitive to angular center, tends to be lower along direction of the projection set, and tends to decrease away from the rotation center. The studies of small as well as large but realistically scaled deformations show similar dependencies. These trends appear to have fairly low sensitivity to quantum noise effects. There is potentially sufficient information present in a small spread of projections to monitor the configuration of reasonably high contrast tumors without implanted markers.

  5. 3D cardiac wall thickening assessment for acute myocardial infarction

    NASA Astrophysics Data System (ADS)

    Khalid, A.; Chan, B. T.; Lim, E.; Liew, Y. M.

    2017-06-01

    Acute myocardial infarction (AMI) is the most severe form of coronary artery disease leading to localized myocardial injury and therefore irregularities in the cardiac wall contractility. Studies have found very limited differences in global indices (such as ejection fraction, myocardial mass and volume) between healthy subjects and AMI patients, and therefore suggested regional assessment. Regional index, specifically cardiac wall thickness (WT) and thickening is closely related to cardiac function and could reveal regional abnormality due to AMI. In this study, we developed a 3D wall thickening assessment method to identify regional wall contractility dysfunction due to localized myocardial injury from infarction. Wall thickness and thickening were assessed from 3D personalized cardiac models reconstructed from cine MRI images by fitting inscribed sphere between endocardial and epicardial wall. The thickening analysis was performed in 5 patients and 3 healthy subjects and the results were compared against the gold standard 2D late-gadolinium-enhanced (LGE) images for infarct localization. The notable finding of this study is the highly accurate estimation and visual representation of the infarct size and location in 3D. This study provides clinicians with an intuitive way to visually and qualitatively assess regional cardiac wall dysfunction due to infarction in AMI patients.

  6. Estimating retained gas volumes in the Hanford tanks using waste level measurements

    SciTech Connect

    Whitney, P.D.; Chen, G.; Gauglitz, P.A.; Meyer, P.A.; Miller, N.E.

    1997-09-01

    The Hanford site is home to 177 large, underground nuclear waste storage tanks. Safety and environmental concerns surround these tanks and their contents. One such concern is the propensity for the waste in these tanks to generate and trap flammable gases. This report focuses on understanding and improving the quality of retained gas volume estimates derived from tank waste level measurements. While direct measurements of gas volume are available for a small number of the Hanford tanks, the increasingly wide availability of tank waste level measurements provides an opportunity for less expensive (than direct gas volume measurement) assessment of gas hazard for the Hanford tanks. Retained gas in the tank waste is inferred from level measurements -- either long-term increase in the tank waste level, or fluctuations in tank waste level with atmospheric pressure changes. This report concentrates on the latter phenomena. As atmospheric pressure increases, the pressure on the gas in the tank waste increases, resulting in a level decrease (as long as the tank waste is {open_quotes}soft{close_quotes} enough). Tanks with waste levels exhibiting fluctuations inversely correlated with atmospheric pressure fluctuations were catalogued in an earlier study. Additionally, models incorporating ideal-gas law behavior and waste material properties have been proposed. These models explicitly relate the retained gas volume in the tank with the magnitude of the waste level fluctuations, dL/dP. This report describes how these models compare with the tank waste level measurements.

  7. Astrometric telescope facility. Preliminary systems definition study. Volume 3: Cost estimate

    NASA Technical Reports Server (NTRS)

    Sobeck, Charlie (Editor)

    1987-01-01

    The results of the Astrometric Telescope Facility (ATF) Preliminary System Definition Study conducted in the period between March and September 1986 are described. The main body of the report consists primarily of the charts presented at the study final review which was held at NASA Ames Research Center on July 30 and 31, 1986. The charts have been revised to reflect the results of that review. Explanations for the charts are provided on the adjoining pages where required. Note that charts which have been changed or added since the review are dated 10/1/86; unchanged charts carry the review date 7/30/86. In addition, a narrative summary is presented of the study results and two appendices. The first appendix is a copy of the ATF Characteristics and Requirements Document generated as part of the study. The second appendix shows the inputs to the Space Station Mission Requirements Data Base submitted in May 1986. The report is issued in three volumes. Volume 1 contains an executive summary of the ATF mission, strawman design, and study results. Volume 2 contains the detailed study information. Volume 3 has the ATF cost estimate, and will have limited distribution.

  8. Association of plasma total homocysteine levels with subclinical brain injury: cerebral volumes, white matter hyperintensity, and silent brain infarcts at volumetric magnetic resonance imaging in the Framingham Offspring Study.

    PubMed

    Seshadri, Sudha; Wolf, Philip A; Beiser, Alexa S; Selhub, Jacob; Au, Rhoda; Jacques, Paul F; Yoshita, Mitsuhiro; Rosenberg, Irwin H; D'Agostino, Ralph B; DeCarli, Charles

    2008-05-01

    Elevated plasma total homocysteine (tHcy) levels have been associated with increased risk of dementia and stroke, but it is uncertain whether the mediating mechanisms are predominantly cellular, vascular, or both. To evaluate the relationship between tHcy levels and findings at brain magnetic resonance imaging (MRI) in a community-based sample. Our sample comprised 1965 participants in the Framingham Offspring Study (1050 women; mean [SD] age, 62 [9] years) who were free of clinical stroke, dementia, or other neurologic disease affecting brain MRI and for whom at least 1 measurement of plasma tHcy level (1991-2001) and a brain MRI (1999-2002) were available. We used multivariate regression analysis to relate initial (1991-1995) and concurrent (1998-2001) plasma tHcy levels to total cerebral brain volume and lobar volumes as measures of neuronal loss and atrophy and to the presence or absence of silent brain infarcts and extensive white matter hyperintensity (log-white matter intensity > or =1 SD above the age-adjusted mean) as separate measures of vascular injury. Mean total cerebral brain volume was 78%. At MRI, 218 participants had silent brain infarcts and 250 demonstrated extensive white matter hyperintensity. Participants with a plasma tHcy level in the highest age- (-0.37%, P = .01) or sex-specific (-0.48%, P < .001) quartile had smaller total cerebral brain volumes compared with participants with lower tHcy levels. Initial tHcy levels were associated with a higher prevalence of silent brain infarct (relative risk, 1.5; 95% confidence interval, 1.1-2.1; P = .02) and concurrent tHcy levels, with smaller frontal (-0.14%, P = .001) and temporal lobar (-0.10%, P = .04) volumes. Prevalence of extensive white matter hyperintensity did not differ according to initial or concurrent plasma tHcy levels (relative risk, both 1.0; 95% confidence interval, 0.7-1.4 and 0.8-1.4, respectively). Higher plasma tHcy levels are associated with smaller brain volume and the

  9. New model for estimating the relationship between surface area and volume in the human body using skeletal remains.

    PubMed

    Kasabova, Boryana E; Holliday, Trenton W

    2015-04-01

    A new model for estimating human body surface area and body volume/mass from standard skeletal metrics is presented. This model is then tested against both 1) "independently estimated" body surface areas and "independently estimated" body volume/mass (both derived from anthropometric data) and 2) the cylindrical model of Ruff. The model is found to be more accurate in estimating both body surface area and body volume/mass than the cylindrical model, but it is more accurate in estimating body surface area than it is for estimating body volume/mass (as reflected by the standard error of the estimate when "independently estimated" surface area or volume/mass is regressed on estimates derived from the present model). Two practical applications of the model are tested. In the first test, the relative contribution of the limbs versus the trunk to the body's volume and surface area is compared between "heat-adapted" and "cold-adapted" populations. As expected, the "cold-adapted" group has significantly more of its body surface area and volume in its trunk than does the "heat-adapted" group. In the second test, we evaluate the effect of variation in bi-iliac breadth, elongated or foreshortened limbs, and differences in crural index on the body's surface area to volume ratio (SA:V). Results indicate that the effects of bi-iliac breadth on SA:V are substantial, while those of limb lengths and (especially) the crural index are minor, which suggests that factors other than surface area relative to volume are driving morphological variation and ecogeographical patterning in limb prorportions.

  10. Tumor target volume for focal therapy of prostate cancer-does multiparametric magnetic resonance imaging allow for a reliable estimation?

    PubMed

    Cornud, F; Khoury, Gaby; Bouazza, Naim; Beuvon, Frederic; Peyromaure, Michael; Flam, Thierry; Zerbib, Marc; Legmann, Paul; Delongchamps, Nicolas B

    2014-05-01

    We determined whether endorectal multiparametric magnetic resonance imaging at 1.5 Tesla could predict tumor target volume in the perspective of focal therapy of prostate cancer. A total of 84 consecutive patients underwent multiparametric magnetic resonance imaging before radical prostatectomy. The volume of each suspicious area detected on magnetic resonance imaging and of all surgical histological foci was determined by planimetry. We first used each magnetic resonance imaging sequence (T2-weighted, diffusion weighted and dynamic contrast enhanced) and then the sequence showing the largest tumor area (multiparametric volume). Finally, the largest area of any sequence was used to calculate a target volume according to the volume of a cylinder. Agreement between magnetic resonance imaging and pathological findings was assessed by linear regression and residual analysis. Histology revealed 99 significant tumors with a volume of greater than 0.2 cc and/or a Gleason score of greater than 6. Of the tumors 16 (16.2%) were undetected by multiparametric magnetic resonance imaging. Linear regression analysis showed that tumor volume estimated by T2-weighted or diffusion weighted imaging correlated significantly with pathological volume (r(2) = 0.82 and 0.83, respectively). Residuals from diffusion weighted imaging volume estimations did not significantly differ from 0. Nevertheless, diffusion weighted imaging underestimated pathological volume in 43 of 87 cases (49%) by a mean of 0.56 cc (range 0.005 to 2.84). Multiparametric and target volumes significantly overestimated pathological volume by a mean of 16% and 44% with underestimation in 28 (32%) and 15 cases (17%), respectively. Volume underestimation was significantly higher for tumor foci less than 0.5 cc. The percent of Gleason grade 4 did not influence tumor volume estimation. Magnetic resonance imaging can detect most significant tumors. However, delineating a target volume may require further adjustment before

  11. Automatic estimation of extent of resection and residual tumor volume of patients with glioblastoma.

    PubMed

    Meier, Raphael; Porz, Nicole; Knecht, Urspeter; Loosli, Tina; Schucht, Philippe; Beck, Jürgen; Slotboom, Johannes; Wiest, Roland; Reyes, Mauricio

    2017-01-06

    OBJECTIVE In the treatment of glioblastoma, residual tumor burden is the only prognostic factor that can be actively influenced by therapy. Therefore, an accurate, reproducible, and objective measurement of residual tumor burden is necessary. This study aimed to evaluate the use of a fully automatic segmentation method-brain tumor image analysis (BraTumIA)-for estimating the extent of resection (EOR) and residual tumor volume (RTV) of contrast-enhancing tumor after surgery. METHODS The imaging data of 19 patients who underwent primary resection of histologically confirmed supratentorial glioblastoma were retrospectively reviewed. Contrast-enhancing tumors apparent on structural preoperative and immediate postoperative MR imaging in this patient cohort were segmented by 4 different raters and the automatic segmentation BraTumIA software. The manual and automatic results were quantitatively compared. RESULTS First, the interrater variabilities in the estimates of EOR and RTV were assessed for all human raters. Interrater agreement in terms of the coefficient of concordance (W) was higher for RTV (W = 0.812; p < 0.001) than for EOR (W = 0.775; p < 0.001). Second, the volumetric estimates of BraTumIA for all 19 patients were compared with the estimates of the human raters, which showed that for both EOR (W = 0.713; p < 0.001) and RTV (W = 0.693; p < 0.001) the estimates of BraTumIA were generally located close to or between the estimates of the human raters. No statistically significant differences were detected between the manual and automatic estimates. BraTumIA showed a tendency to overestimate contrast-enhancing tumors, leading to moderate agreement with expert raters with respect to the literature-based, survival-relevant threshold values for EOR. CONCLUSIONS BraTumIA can generate volumetric estimates of EOR and RTV, in a fully automatic fashion, which are comparable to the estimates of human experts. However, automated analysis showed a tendency to overestimate

  12. Glass Property Data and Models for Estimating High-Level Waste Glass Volume

    SciTech Connect

    Vienna, John D.; Fluegel, Alexander; Kim, Dong-Sang; Hrma, Pavel R.

    2009-10-05

    This report describes recent efforts to develop glass property models that can be used to help estimate the volume of high-level waste (HLW) glass that will result from vitrification of Hanford tank waste. The compositions of acceptable and processable HLW glasses need to be optimized to minimize the waste-form volume and, hence, to save cost. A database of properties and associated compositions for simulated waste glasses was collected for developing property-composition models. This database, although not comprehensive, represents a large fraction of data on waste-glass compositions and properties that were available at the time of this report. Glass property-composition models were fit to subsets of the database for several key glass properties. These models apply to a significantly broader composition space than those previously publised. These models should be considered for interim use in calculating properties of Hanford waste glasses.

  13. Estimation of the total saliva volume produced per day in five-year-old children.

    PubMed

    Watanabe, S; Ohnishi, M; Imai, K; Kawano, E; Igarashi, S

    1995-08-01

    Fifteen boys and 15 girls were asked to record for 2 days the time spent awake, eating meals or snacks, and sleeping. The salivary flow rates elicited by chewing foods were also determined. The mean flow rate (+/- SD) of unstimulated saliva was 0.26 +/- 0.16 ml/min and that of saliva while chewing six different foods was 3.6 +/- 0.8 ml/min. The mean times spent eating, and awake but not eating, were 80.8 +/- 27.3 and 820 +/- 59 min, respectively, and the volumes of saliva produced during those periods would average about 288 and 208 ml, respectively. If the flow rate is virtually zero during sleep, the estimated total salivary volume produced per day is calculated to be about 500 ml.

  14. Generalized method for partial volume estimation and tissue segmentation in cerebral magnetic resonance images

    PubMed Central

    Khademi, April; Venetsanopoulos, Anastasios; Moody, Alan R.

    2014-01-01

    Abstract. An artifact found in magnetic resonance images (MRI) called partial volume averaging (PVA) has received much attention since accurate segmentation of cerebral anatomy and pathology is impeded by this artifact. Traditional neurological segmentation techniques rely on Gaussian mixture models to handle noise and PVA, or high-dimensional feature sets that exploit redundancy in multispectral datasets. Unfortunately, model-based techniques may not be optimal for images with non-Gaussian noise distributions and/or pathology, and multispectral techniques model probabilities instead of the partial volume (PV) fraction. For robust segmentation, a PV fraction estimation approach is developed for cerebral MRI that does not depend on predetermined intensity distribution models or multispectral scans. Instead, the PV fraction is estimated directly from each image using an adaptively defined global edge map constructed by exploiting a relationship between edge content and PVA. The final PVA map is used to segment anatomy and pathology with subvoxel accuracy. Validation on simulated and real, pathology-free T1 MRI (Gaussian noise), as well as pathological fluid attenuation inversion recovery MRI (non-Gaussian noise), demonstrate that the PV fraction is accurately estimated and the resultant segmentation is robust. Comparison to model-based methods further highlight the benefits of the current approach. PMID:26158022

  15. The estimation of the thyroid volume before surgery--an important prerequisite for minimally invasive thyroidectomy.

    PubMed

    Ruggieri, M; Fumarola, A; Straniero, A; Maiuolo, A; Coletta, I; Veltri, A; Di Fiore, A; Trimboli, P; Gargiulo, P; Genderini, M; D'Armiento, M

    2008-09-01

    Actually, thyroid volume >25 ml, obtained by preoperative ultrasound evaluation, is a very important exclusion criteria for minimally invasive thyroidectomy. So far, among different imaging techniques, two-dimensional ultrasonography has become the more accepted method for the assessment of thyroid volume (US-TV). The aims of this study were: (1) to estimate the preoperative thyroid volume in patients undergoing minimally invasive total thyroidectomy using a mathematical formula and (2) to verify its validity by comparing it with the postsurgical TV (PS-TV). In 53 patients who underwent minimally invasive total thyroidectomy (from January 2003 to December 2007), US-TV, obtained by ellipsoid volume formula, was compared to PS-TV determined by the Archimedes' principle. A mathematical formula able to predict the TV from the US-TV was applied in 34 cases in the last 2 years. Mean US-TV (14.4 +/- 5.9 ml) was significantly lower than mean PS-TV (21.7 +/- 10.3 ml). This underestimation was related to gland multinodularity and/or nodular involvement of the isthmus. A mathematical formula to reduce US-TV underestimation and predict the real TV was developed using a linear model. Mean predicted TV (16.8 +/- 3.7 ml) perfectly matched mean PS-TV, underestimating PS-TV in 19% of cases. We verified the accuracy of this mathematical model in patients' eligibility for minimally invasive total thyroidectomy, and we demonstrated that a predicted TV <25 ml was confirmed post-surgery in 94% of cases. We demonstrated that using a linear model, it is possible to predict from US the PS-TV with high accuracy. In fact, the mean predicted TV perfectly matched the mean PS-TV in all cases. In particular, the percentage of cases in which the predicted TV perfectly matched the PS-TV increases from 23%, estimated by US, to 43%. Moreover, the percentage of TV underestimation was reduced from 77% to 19%, as well as the range of the disagreement from up to 200% to 80%. This study shows that two

  16. Use of inverse probability weighting to adjust for non-participation in estimating brain volumes in schizophrenia patients.

    PubMed

    Haapea, Marianne; Veijola, Juha; Tanskanen, Päivikki; Jääskeläinen, Erika; Isohanni, Matti; Miettunen, Jouko

    2011-12-30

    Low participation is a potential source of bias in population-based studies. This article presents use of inverse probability weighting (IPW) in adjusting for non-participation in estimation of brain volumes among subjects with schizophrenia. Altogether 101 schizophrenia subjects and 187 non-psychotic comparison subjects belonging to the Northern Finland 1966 Birth Cohort were invited to participate in a field study during 1999-2001. Volumes of grey matter (GM), white matter (WM) and cerebrospinal fluid (CSF) were compared between the 54 participating schizophrenia subjects and 100 comparison subjects. IPW by illness-related auxiliary variables did not affect the estimated GM and WM mean volumes, but increased the estimated CSF mean volume in schizophrenia subjects. When adjusted for intracranial volume and family history of psychosis, IPW led to smaller estimated GM and WM mean volumes. Especially IPW by a disability pension and a higher amount of hospitalisation due to psychosis had effect on estimated mean brain volumes. The IPW method can be used to improve estimates affected by non-participation by reflecting the true differences in the target population.

  17. Estimating Marine Aerosol Particle Volume and Number from Maritime Aerosol Network Data

    NASA Technical Reports Server (NTRS)

    Sayer, A. M.; Smirnov, A.; Hsu, N. C.; Munchak, L. A.; Holben, B. N.

    2012-01-01

    As well as spectral aerosol optical depth (AOD), aerosol composition and concentration (number, volume, or mass) are of interest for a variety of applications. However, remote sensing of these quantities is more difficult than for AOD, as it is more sensitive to assumptions relating to aerosol composition. This study uses spectral AOD measured on Maritime Aerosol Network (MAN) cruises, with the additional constraint of a microphysical model for unpolluted maritime aerosol based on analysis of Aerosol Robotic Network (AERONET) inversions, to estimate these quantities over open ocean. When the MAN data are subset to those likely to be comprised of maritime aerosol, number and volume concentrations obtained are physically reasonable. Attempts to estimate surface concentration from columnar abundance, however, are shown to be limited by uncertainties in vertical distribution. Columnar AOD at 550 nm and aerosol number for unpolluted maritime cases are also compared with Moderate Resolution Imaging Spectroradiometer (MODIS) data, for both the present Collection 5.1 and forthcoming Collection 6. MODIS provides a best-fitting retrieval solution, as well as the average for several different solutions, with different aerosol microphysical models. The average solution MODIS dataset agrees more closely with MAN than the best solution dataset. Terra tends to retrieve lower aerosol number than MAN, and Aqua higher, linked with differences in the aerosol models commonly chosen. Collection 6 AOD is likely to agree more closely with MAN over open ocean than Collection 5.1. In situations where spectral AOD is measured accurately, and aerosol microphysical properties are reasonably well-constrained, estimates of aerosol number and volume using MAN or similar data would provide for a greater variety of potential comparisons with aerosol properties derived from satellite or chemistry transport model data.

  18. Spatial and temporal skin blood volume and saturation estimation using a multispectral snapshot imaging camera

    NASA Astrophysics Data System (ADS)

    Ewerlöf, Maria; Larsson, Marcus; Salerud, E. Göran

    2017-02-01

    Hyperspectral imaging (HSI) can estimate the spatial distribution of skin blood oxygenation, using visible to near-infrared light. HSI oximeters often use a liquid-crystal tunable filter, an acousto-optic tunable filter or mechanically adjustable filter wheels, which has too long response/switching times to monitor tissue hemodynamics. This work aims to evaluate a multispectral snapshot imaging system to estimate skin blood volume and oxygen saturation with high temporal and spatial resolution. We use a snapshot imager, the xiSpec camera (MQ022HG-IM-SM4X4-VIS, XIMEA), having 16 wavelength-specific Fabry-Perot filters overlaid on the custom CMOS-chip. The spectral distribution of the bands is however substantially overlapping, which needs to be taken into account for an accurate analysis. An inverse Monte Carlo analysis is performed using a two-layered skin tissue model, defined by epidermal thickness, haemoglobin concentration and oxygen saturation, melanin concentration and spectrally dependent reduced-scattering coefficient, all parameters relevant for human skin. The analysis takes into account the spectral detector response of the xiSpec camera. At each spatial location in the field-of-view, we compare the simulated output to the detected diffusively backscattered spectra to find the best fit. The imager is evaluated for spatial and temporal variations during arterial and venous occlusion protocols applied to the forearm. Estimated blood volume changes and oxygenation maps at 512x272 pixels show values that are comparable to reference measurements performed in contact with the skin tissue. We conclude that the snapshot xiSpec camera, paired with an inverse Monte Carlo algorithm, permits us to use this sensor for spatial and temporal measurement of varying physiological parameters, such as skin tissue blood volume and oxygenation.

  19. Space transfer vehicle concepts and requirements. Volume 3: Program cost estimates

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Space Transfer Vehicle (STV) Concepts and Requirements Study has been an eighteen-month study effort to develop and analyze concepts for a family of vehicles to evolve from an initial STV system into a Lunar Transportation System (LTS) for use with the Heavy Lift Launch Vehicle (HLLV). The study defined vehicle configurations, facility concepts, and ground and flight operations concepts. This volume reports the program cost estimates results for this portion of the study. The STV Reference Concept described within this document provides a complete LTS system that performs both cargo and piloted Lunar missions.

  20. Estimates of plasma, packed cell and total blood volume in tissues of the rainbow trout (Salmo gairdneri)

    USGS Publications Warehouse

    Gingerich, W.H.; Pityer, R.A.; Rach, J.J.

    1987-01-01

    1. Total blood volume and relative blood volumes in selected tissues were determined in non-anesthetized, confined rainbow trout by using 51Cr-labelled trout erythrocytes as a vascular space marker.2. Mean total blood volume was estimated to be 4.09 ± 0.55 ml/100 g, or about 75% of that estimated with the commonly used plasma space marker Evans blue dye.3. Relative tissue blood volumes were greatest in highly perfused tissues such as kidney, gills, brain and liver and least in mosaic muscle.4. Estimates of tissue vascular spaces, made using radiolabelled erythrocytes, were only 25–50% of those based on plasma space markers.5. The consistently smaller vascular volumes obtained with labelled erythrocytes could be explained by assuming that commonly used plasma space markers diffuse from the vascular compartment.

  1. Estimates of plasma, packed cell and total blood volume in tissues of the rainbow trout (Salmo gairdneri )

    USGS Publications Warehouse

    Gingerich, W.H.; Pityer, R.A.; Rach, J.J.

    1987-01-01

    Total blood volume and relative blood volumes in selected tissues were determined in non-anesthetized, confined rainbow trout by using super(51)Cr-labelled trout erythrocytes as a vascular space marker. Mean total blood volume was estimated to be 4.09 plus or minus 0.55 ml/100 g, or about 75% of that estimated with the commonly used plasma space marker Evans blue dye. Relative tissue blood volumes were greatest in highly perfused tissues such as kidney, gills, brain and liver and least in mosaic muscle. Estimates of tissue vascular spaces, made using radiolabelled erythrocytes, were only 25-50% of those based on plasma space markers. The consistently smaller vascular volumes obtained with labelled erythrocytes could be explained by assuming that commonly used plasma space markers diffuse from the vascular compartment.

  2. Sickle cell anemia: intracranial stenosis and silent cerebral infarcts in children with low risk of stroke.

    PubMed

    Arkuszewski, Michal; Krejza, Jaroslaw; Chen, Rong; Ichord, Rebecca; Kwiatkowski, Janet L; Bilello, Michel; Zimmerman, Robert; Ohene-Frempong, Kwaku; Melhem, Elias R

    2014-03-01

    Children with sickle cell anemia (SCA), who have mean blood flow velocities <170 cm/s in the terminal internal carotid (tICA) or middle cerebral (MCA) arteries on transcranial Doppler ultrasonography (TCD), are considered to be at low risk of stroke. The prevalence of intracranial stenosis, which raises the risk of stroke, is not known in these children. Here, we estimated the prevalence of stenosis and explored its association with silent cerebral infarcts determined based on Magnetic Resonance (MR) scans. We studied prospectively a cohort of 67 children with SCA without prior clinically overt stroke or TIA (median age 8.8 years; range limits 2.3-13.1 years; 33 females) and with TCD mean velocity <170 cm/s. They underwent MR imaging of the brain and MR angiography of intracranial arteries. In 7 children (10.5%, 95% CI: 4.9-20.3%) we found 10 stenoses, including 4 with isolated left tICA stenosis and 3 with multiple stenoses. We found silent infarcts in 26 children (37.7%, 95% CI: 27.2-49.5%). The median number of infarcts in an affected child was 2 (range limits: 1-9), median volume of infarcts was 171 mm(3) (range limits: 7-1060 mm(3)), and median infarct volume in relation to total brain volume was 0.020% (range limits: 0.001-0.101%). The number and volume of infarcts were significantly higher in children with arterial stenosis (both p=0.023). The prevalence of intracranial arterial stenosis in children with SCA classified as at low risk of stroke by TCD mean velocity <170 cm/s is high. Children with stenosis are at higher risk of brain parenchymal injury as they have more silent cerebral infarcts. Copyright © 2014 Medical University of Bialystok. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  3. Caudate infarcts.

    PubMed

    Caplan, L R; Schmahmann, J D; Kase, C S; Feldmann, E; Baquis, G; Greenberg, J P; Gorelick, P B; Helgason, C; Hier, D B

    1990-02-01

    Eighteen patients had caudate nucleus infarcts (10 left-sided; 8 right-sided). Infarcts extended into the anterior limb of the internal capsule in 9 patients, and also the anterior putamen in 5 patients. Thirteen patients had motor signs, most often a slight transient hemiparesis. Dysarthria was common (11 patients). Cognitive and behavioral abnormalities were frequent, and included abulia (10 patients), agitation and hyperactivity (7 patients), contralateral neglect (3 patients, all right caudate), and language abnormalities (2 patients, both left caudate). The majority of patients had risk factors for penetrating artery disease. Branch occlusion of Heubner's artery, or perforators from the proximal anterior or middle cerebral arteries were the posited mechanism of infarction.

  4. A simple method for accurate liver volume estimation by use of curve-fitting: a pilot study.

    PubMed

    Aoyama, Masahito; Nakayama, Yoshiharu; Awai, Kazuo; Inomata, Yukihiro; Yamashita, Yasuyuki

    2013-01-01

    In this paper, we describe the effectiveness of our curve-fitting method by comparing liver volumes estimated by our new technique to volumes obtained with the standard manual contour-tracing method. Hepatic parenchymal-phase images of 13 patients were obtained with multi-detector CT scanners after intravenous bolus administration of 120-150 mL of contrast material (300 mgI/mL). The liver contours of all sections were traced manually by an abdominal radiologist, and the liver volume was computed by summing of the volumes inside the contours. The section number between the first and last slice was then divided into 100 equal parts, and each volume was re-sampled by use of linear interpolation. We generated 13 model profile curves by averaging 12 cases, leaving out one case, and we estimated the profile curve for each patient by fitting the volume values at 4 points using a scale and translation transform. Finally, we determined the liver volume by integrating the sampling points of the profile curve. We used Bland-Altman analysis to evaluate the agreement between the volumes estimated with our curve-fitting method and the volumes measured by the manual contour-tracing method. The correlation between the volume measured by manual tracing and that estimated with our curve-fitting method was relatively high (r = 0.98; slope 0.97; p < 0.001). The mean difference between the manual tracing and our method was -22.9 cm(3) (SD of the difference, 46.2 cm(3)). Our volume-estimating technique that requires the tracing of only 4 images exhibited a relatively high linear correlation with the manual tracing technique.

  5. Comparison of three methods for the estimation of the pituitary gland volume using magnetic resonance imaging: a stereological study.

    PubMed

    Ertekin, Tolga; Acer, Niyazi; Turgut, Ahmet T; Aycan, Kenan; Ozçelik, Ozlem; Turgut, Mehmet

    2011-03-01

    Stereological techniques using point counting and planimetry have been used to estimate pituitary gland volume. However, many studies have estimated pituitary gland volume by the mathematical approach the elliptic formula. The objective of the current study was to determine pituitary gland volume using stereological methods and elliptic formula on magnetic resonance imaging (MRI). In this study, pituitary gland volumes were estimated in a total of 28 subjects (22 females, 6 males,) who were free of any pituitary or neurological symptoms and signs. The mean ± SD pituitary gland volumes for the point counting, planimetry and elliptic formulae groups were 582.14 ± 140.16 mm³, 610.08 ± 133.17 mm³, and 432.82 ± 147.38 mm³, respectively. The mean CE for the pituitary gland volume estimates derived from the point counting technique was 8.07%. No significant difference was found between point counting and planimetric methods for the pituitary gland volume (P > 0.05). In addition, there was a 26.14 and 29.71% underestimation of pituitary volume as measured by the elliptic formula compared to the point counting and planimetric techniques, respectively. From these results, it can be concluded that stereological techniques are unbiased, efficient and reliable methods and are ideally suitable for in vivo examination of MRI data for pituitary gland volume estimation. Hence, we suggest that estimating pituitary gland volume using MRI study and stereology may be clinically relevant for pituitary surgeons for the investigation of the structure and function of the pituitary gland.

  6. Improved dose-volume histogram estimates for radiopharmaceutical therapy by optimizing quantitative SPECT reconstruction parameters

    NASA Astrophysics Data System (ADS)

    Cheng, Lishui; Hobbs, Robert F.; Segars, Paul W.; Sgouros, George; Frey, Eric C.

    2013-06-01

    In radiopharmaceutical therapy, an understanding of the dose distribution in normal and target tissues is important for optimizing treatment. Three-dimensional (3D) dosimetry takes into account patient anatomy and the nonuniform uptake of radiopharmaceuticals in tissues. Dose-volume histograms (DVHs) provide a useful summary representation of the 3D dose distribution and have been widely used for external beam treatment planning. Reliable 3D dosimetry requires an accurate 3D radioactivity distribution as the input. However, activity distribution estimates from SPECT are corrupted by noise and partial volume effects (PVEs). In this work, we systematically investigated OS-EM based quantitative SPECT (QSPECT) image reconstruction in terms of its effect on DVHs estimates. A modified 3D NURBS-based Cardiac-Torso (NCAT) phantom that incorporated a non-uniform kidney model and clinically realistic organ activities and biokinetics was used. Projections were generated using a Monte Carlo (MC) simulation; noise effects were studied using 50 noise realizations with clinical count levels. Activity images were reconstructed using QSPECT with compensation for attenuation, scatter and collimator-detector response (CDR). Dose rate distributions were estimated by convolution of the activity image with a voxel S kernel. Cumulative DVHs were calculated from the phantom and QSPECT images and compared both qualitatively and quantitatively. We found that noise, PVEs, and ringing artifacts due to CDR compensation all degraded histogram estimates. Low-pass filtering and early termination of the iterative process were needed to reduce the effects of noise and ringing artifacts on DVHs, but resulted in increased degradations due to PVEs. Large objects with few features, such as the liver, had more accurate histogram estimates and required fewer iterations and more smoothing for optimal results. Smaller objects with fine details, such as the kidneys, required more iterations and less

  7. Improved dose-volume histogram estimates for radiopharmaceutical therapy by optimizing quantitative SPECT reconstruction parameters.

    PubMed

    Cheng, Lishui; Hobbs, Robert F; Segars, Paul W; Sgouros, George; Frey, Eric C

    2013-06-07

    In radiopharmaceutical therapy, an understanding of the dose distribution in normal and target tissues is important for optimizing treatment. Three-dimensional (3D) dosimetry takes into account patient anatomy and the nonuniform uptake of radiopharmaceuticals in tissues. Dose-volume histograms (DVHs) provide a useful summary representation of the 3D dose distribution and have been widely used for external beam treatment planning. Reliable 3D dosimetry requires an accurate 3D radioactivity distribution as the input. However, activity distribution estimates from SPECT are corrupted by noise and partial volume effects (PVEs). In this work, we systematically investigated OS-EM based quantitative SPECT (QSPECT) image reconstruction in terms of its effect on DVHs estimates. A modified 3D NURBS-based Cardiac-Torso (NCAT) phantom that incorporated a non-uniform kidney model and clinically realistic organ activities and biokinetics was used. Projections were generated using a Monte Carlo (MC) simulation; noise effects were studied using 50 noise realizations with clinical count levels. Activity images were reconstructed using QSPECT with compensation for attenuation, scatter and collimator-detector response (CDR). Dose rate distributions were estimated by convolution of the activity image with a voxel S kernel. Cumulative DVHs were calculated from the phantom and QSPECT images and compared both qualitatively and quantitatively. We found that noise, PVEs, and ringing artifacts due to CDR compensation all degraded histogram estimates. Low-pass filtering and early termination of the iterative process were needed to reduce the effects of noise and ringing artifacts on DVHs, but resulted in increased degradations due to PVEs. Large objects with few features, such as the liver, had more accurate histogram estimates and required fewer iterations and more smoothing for optimal results. Smaller objects with fine details, such as the kidneys, required more iterations and less

  8. Estimation of volume and mass and of changes in volume and mass of selected chat piles in the Picher mining district, Ottawa County, Oklahoma, 2005-10

    USGS Publications Warehouse

    Smith, S. Jerrod

    2013-01-01

    From the 1890s through the 1970s the Picher mining district in northeastern Ottawa County, Oklahoma, was the site of mining and processing of lead and zinc ore. When mining ceased in about 1979, as much as 165–300 million tons of mine tailings, locally referred to as “chat,” remained in the Picher mining district. Since 1979, some chat piles have been mined for aggregate materials and have decreased in volume and mass. Currently (2013), the land surface in the Picher mining district is covered by thousands of acres of chat, much of which remains on Indian trust land owned by allottees. The Bureau of Indian Affairs manages these allotted lands and oversees the sale and removal of chat from these properties. To help the Bureau of Indian Affairs better manage the sale and removal of chat, the U.S. Geological Survey, in cooperation with the Bureau of Indian Affairs, estimated the 2005 and 2010 volumes and masses of selected chat piles remaining on allotted lands in the Picher mining district. The U.S. Geological Survey also estimated the changes in volume and mass of these chat piles for the period 2005 through 2010. The 2005 and 2010 chat-pile volume and mass estimates were computed for 34 selected chat piles on 16 properties in the study area. All computations of volume and mass were performed on individual chat piles and on groups of chat piles in the same property. The Sooner property had the greatest estimated volume (4.644 million cubic yards) and mass (5.253 ± 0.473 million tons) of chat in 2010. Five of the selected properties (Sooner, Western, Lawyers, Skelton, and St. Joe) contained estimated chat volumes exceeding 1 million cubic yards and estimated chat masses exceeding 1 million tons in 2010. Four of the selected properties (Lucky Bill Humbah, Ta Mee Heh, Bird Dog, and St. Louis No. 6) contained estimated chat volumes of less than 0.1 million cubic yards and estimated chat masses of less than 0.1 million tons in 2010. The total volume of all

  9. Comparison of 2-D and 3-D estimates of placental volume in early pregnancy.

    PubMed

    Aye, Christina Y L; Stevenson, Gordon N; Impey, Lawrence; Collins, Sally L

    2015-03-01

    Ultrasound estimation of placental volume (PlaV) between 11 and 13 wk has been proposed as part of a screening test for small-for-gestational-age babies. A semi-automated 3-D technique, validated against the gold standard of manual delineation, has been found at this stage of gestation to predict small-for-gestational-age at term. Recently, when used in the third trimester, an estimate obtained using a 2-D technique was found to correlate with placental weight at delivery. Given its greater simplicity, the 2-D technique might be more useful as part of an early screening test. We investigated if the two techniques produced similar results when used in the first trimester. The correlation between PlaV values calculated by the two different techniques was assessed in 139 first-trimester placentas. The agreement on PlaV and derived "standardized placental volume," a dimensionless index correcting for gestational age, was explored with the Mann-Whitney test and Bland-Altman plots. Placentas were categorized into five different shape subtypes, and a subgroup analysis was performed. Agreement was poor for both PlaV and standardized PlaV (p < 0.001 and p < 0.001), with the 2-D technique yielding larger estimates for both indices compared with the 3-D method. The mean difference in standardized PlaV values between the two methods was 0.007 (95% confidence interval: 0.006-0.009). The best agreement was found for regular rectangle-shaped placentas (p = 0.438 and p = 0.408). The poor correlation between the 2-D and 3-D techniques may result from the heterogeneity of placental morphology at this stage of gestation. In early gestation, the simpler 2-D estimates of PlaV do not correlate strongly with those obtained with the validated 3-D technique.

  10. Estimating Volume, Biomass, and Carbon in Hedmark County, Norway Using a Profiling LiDAR

    NASA Technical Reports Server (NTRS)

    Nelson, Ross; Naesset, Erik; Gobakken, T.; Gregoire, T.; Stahl, G.

    2009-01-01

    A profiling airborne LiDAR is used to estimate the forest resources of Hedmark County, Norway, a 27390 square kilometer area in southeastern Norway on the Swedish border. One hundred five profiling flight lines totaling 9166 km were flown over the entire county; east-west. The lines, spaced 3 km apart north-south, duplicate the systematic pattern of the Norwegian Forest Inventory (NFI) ground plot arrangement, enabling the profiler to transit 1290 circular, 250 square meter fixed-area NFI ground plots while collecting the systematic LiDAR sample. Seven hundred sixty-three plots of the 1290 plots were overflown within 17.8 m of plot center. Laser measurements of canopy height and crown density are extracted along fixed-length, 17.8 m segments closest to the center of the ground plot and related to basal area, timber volume and above- and belowground dry biomass. Linear, nonstratified equations that estimate ground-measured total aboveground dry biomass report an R(sup 2) = 0.63, with an regression RMSE = 35.2 t/ha. Nonstratified model results for the other biomass components, volume, and basal area are similar, with R(sup 2) values for all models ranging from 0.58 (belowground biomass, RMSE = 8.6 t/ha) to 0.63. Consistently, the most useful single profiling LiDAR variable is quadratic mean canopy height, h (sup bar)(sub qa). Two-variable models typically include h (sup bar)(sub qa) or mean canopy height, h(sup bar)(sub a), with a canopy density or a canopy height standard deviation measure. Stratification by productivity class did not improve the nonstratified models, nor did stratification by pine/spruce/hardwood. County-wide profiling LiDAR estimates are reported, by land cover type, and compared to NFI estimates.

  11. Estimating Volume, Biomass, and Carbon in Hedmark County, Norway Using a Profiling LiDAR

    NASA Technical Reports Server (NTRS)

    Nelson, Ross; Naesset, Erik; Gobakken, T.; Gregoire, T.; Stahl, G.

    2009-01-01

    A profiling airborne LiDAR is used to estimate the forest resources of Hedmark County, Norway, a 27390 square kilometer area in southeastern Norway on the Swedish border. One hundred five profiling flight lines totaling 9166 km were flown over the entire county; east-west. The lines, spaced 3 km apart north-south, duplicate the systematic pattern of the Norwegian Forest Inventory (NFI) ground plot arrangement, enabling the profiler to transit 1290 circular, 250 square meter fixed-area NFI ground plots while collecting the systematic LiDAR sample. Seven hundred sixty-three plots of the 1290 plots were overflown within 17.8 m of plot center. Laser measurements of canopy height and crown density are extracted along fixed-length, 17.8 m segments closest to the center of the ground plot and related to basal area, timber volume and above- and belowground dry biomass. Linear, nonstratified equations that estimate ground-measured total aboveground dry biomass report an R(sup 2) = 0.63, with an regression RMSE = 35.2 t/ha. Nonstratified model results for the other biomass components, volume, and basal area are similar, with R(sup 2) values for all models ranging from 0.58 (belowground biomass, RMSE = 8.6 t/ha) to 0.63. Consistently, the most useful single profiling LiDAR variable is quadratic mean canopy height, h (sup bar)(sub qa). Two-variable models typically include h (sup bar)(sub qa) or mean canopy height, h(sup bar)(sub a), with a canopy density or a canopy height standard deviation measure. Stratification by productivity class did not improve the nonstratified models, nor did stratification by pine/spruce/hardwood. County-wide profiling LiDAR estimates are reported, by land cover type, and compared to NFI estimates.

  12. Association of bioimpedance spectroscopy-based volume estimation with postdialysis hypotension in patients receiving hemodialysis

    PubMed Central

    ABREO, Adrian P.; CHERTOW, Glenn M.; DALRYMPLE, Lorien S.; KAYSEN, George A.; JOHANSEN, Kirsten L.

    2016-01-01

    Clinical examination to determine the dry weight of patients on hemodialysis (HD) has been problematic, with studies showing discordance between physician assessment and objective measures of volume status. We studied the association between predialysis bioimpedance spectroscopy (BIS)-based estimates of fluid overload and postdialysis hypotension in 635 patients in the United States Renal Data System ACTIVE/ADIPOSE (A Cohort study To Investigate the Value of Exercise/Analyses Designed to Investigate the Paradox of Obesity and Survival in ESRD) study receiving HD in 2009–2011. We recorded predialysis and postdialysis weight and blood pressures over 3 consecutive HD sessions and performed BIS before a single session. Using a previously reported method of estimating normohydration weight, we estimated postdialysis fluid overload (FOpost) in liters. We used logistic regression with extracellular water/total body water (ECW/TBW) or estimated FOpost as the primary predictor and 1 or more postdialysis systolic blood pressures less than 110 mmHg as the dependent variable. Models were adjusted for age, sex, race, ultrafiltration rate per kilogram of body weight, end-stage renal disease vintage, diabetes mellitus, heart failure, and albumin. Higher ECW/TBW was associated with lower odds of postdialysis hypotension (odds ratio [OR] 0.35, 95% confidence interval [CI] 0.15–0.84 per 0.1, P = 0.02). Every liter of FOpost was associated with lower adjusted odds of postdialysis hypotension (OR 0.86, 95% CI 0.79–0.95, P = 0.003). Prospective studies are needed to determine whether this application of BIS could improve current clinical efforts to minimize episodes of postdialysis hypotension without leading to volume overload. PMID:25881673

  13. Breast volume estimation from systematic series of CT scans using the Cavalieri principle and 3D reconstruction.

    PubMed

    Erić, Mirela; Anderla, Andraš; Stefanović, Darko; Drapšin, Miodrag

    2014-01-01

    Preoperative breast volume estimation is very important for the success of the breast surgery. In the present study, two different breast volume determination methods, Cavalieri principle and 3D reconstruction were compared. Consecutive sections were taken in slice thickness of 5 mm. Every 2nd breast section in a set of consecutive sections was selected. We marked breast tissue with blue line on each selected section, and so prepared CT scans used for breast volume estimation. The volumes of the 60 breasts were estimated using the Cavalieri principle and 3D reconstruction. The mean breast volume value was established to be 467.79 ± 188.90 cm(3) with Cavalieri method and 465.91 ± 191.41 cm(3) with 3D reconstruction. The mean CE for the estimates in this study was calculated as 0.25%. Skin-sparing volume was about 91.64% of the whole breast volume. Both methods are very accurate and have a strong linear association. Our results suggest that the calculation of breast volume or its part in vivo from systematic series of CT scans using the Cavalieri principle or 3D breast reconstruction is accurate enough to have a significant clinical benefit in planning reconstructive breast surgery. These methods can help the surgeon guide the choice of the most appropriate implant or/and flap preoperatively. Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  14. Myocardial Infarct Size Measurement in the Mouse Chronic Infarction Model: Comparison of Area- and Length-Based Approaches

    PubMed Central

    Takagawa, Junya; Zhang, Yan; Wong, Maelene L.; Sievers, Richard E.; Kapasi, Neel K.; Wang, Yan; Yeghiazarians, Yerem; Lee, Randall J.; Grossman, William; Springer, Matthew L.

    2009-01-01

    Efficacy of potential treatments for myocardial infarction (MI) is commonly assessed by histological measurement of infarct size in rodent models. In experiments involving an acute MI setting, measurement of the infarcted area in tissue sections of the left ventricle (LV) is a standard approach to determine infarct size. This approach has also been used in the chronic infarct setting to measure infarct area several weeks post-MI. We tested the hypothesis that due to wall thinning that is known to occur in the chronic setting, the area measurement approach would be less appropriate. We compared infarct measurements in tissue sections based on (1) infarct area, (2) epicardial and endocardial infarct arc lengths, and (3) midline infarct arc length. Infarct size from all three measurement approaches correlated significantly with LV ejection fraction (LVEF) and wall motion abnormality. However, the infarct size values derived from area measurement were significantly smaller than those from the other measurements, and the range of values obtained was compressed 0.4-fold. The midline method was able to detect the expected size differences between infarcts of variable severity resulting from proximal vs. distal ligation of the coronary artery. Segmental infarct size was correlated with segmental wall motion abnormality. We conclude that both area- and length-based measurements can determine relative infarct size over a wide range of severity but the area-based measurements are substantially more compressed due to wall thinning, and that the estimation of infarct midlines is a simple, reliable approach to infarct size assessment. PMID:17347379

  15. Estimated probabilities and volumes of postwildfire debris flows, a prewildfire evaluation for the upper Blue River watershed, Summit County, Colorado

    USGS Publications Warehouse

    Elliott, John G.; Flynn, Jennifer L.; Bossong, Clifford R.; Char, Stephen J.

    2011-01-01

    The subwatersheds with the greatest potential postwildfire and postprecipitation hazards are those with both high probabilities of debris-flow occurrence and large estimated volumes of debris-flow material. The high probabilities of postwildfire debris flows, the associated large estimated debris-flow volumes, and the densely populated areas along the creeks and near the outlets of the primary watersheds indicate that Indiana, Pennsylvania, and Spruce Creeks are associated with a relatively high combined debris-flow hazard.

  16. Single-cell volume estimation by applying three-dimensional reconstruction methods

    NASA Astrophysics Data System (ADS)

    Khatibi, Siamak; Allansson, Louise; Gustavsson, Tomas; Blomstrand, Fredrik; Hansson, Elisabeth; Olsson, Torsten

    1999-05-01

    We have studied three-dimensional reconstruction methods to estimate the cell volume of astroglial cells in primary culture. The studies are based on fluorescence imaging and optical sectioning. An automated image-acquisition system was developed to collect two-dimensional microscopic images. Images were reconstructed by the Linear Maximum a Posteriori method and the non-linear Maximum Likelihood Expectation Maximization (ML-EM) method. In addition, because of the high computational demand of the ML-EM algorithm, we have developed a fast variant of this method. (1) Advanced image analysis techniques were applied for accurate and automated cell volume determination. (2) The sensitivity and accuracy of the reconstruction methods were evaluated by using fluorescent micro-beads with known diameter. The algorithms were applied to fura-2-labeled astroglial cells in primary culture exposed to hypo- or hyper-osmotic stress. The results showed that the ML-EM reconstructed images are adequate for the determination of volume changes in cells or parts thereof.

  17. Improved estimates for the role of grey matter volume and GABA in bistable perception.

    PubMed

    Sandberg, Kristian; Blicher, Jakob Udby; Del Pin, Simon Hviid; Andersen, Lau Møller; Rees, Geraint; Kanai, Ryota

    2016-10-01

    Across a century or more, ambiguous stimuli have been studied scientifically because they provide a method for studying the internal mechanisms of the brain while ensuring an unchanging external stimulus. In recent years, several studies have reported correlations between perceptual dynamics during bistable perception and particular brain characteristics such as the grey matter volume of areas in the superior parietal lobule (SPL) and the relative GABA concentration in the occipital lobe. Here, we attempt to replicate previous results using similar paradigms to those used in the studies first reporting the correlations. Using the original findings as priors for Bayesian analyses, we found strong support for the correlation between structure-from-motion percept duration and anterior SPL grey matter volume. Correlations between percept duration and other parietal areas as well as occipital GABA, however, were not directly replicated or appeared less strong than previous studies suggested. Inspection of the posterior distributions (current "best guess" based on new data given old data as prior) revealed that several original findings may reflect true relationships although no direct evidence was found in support of them in the current sample. Additionally, we found that multiple regression models based on grey matter volume at 2-3 parietal locations (but not including GABA) were the best predictors of percept duration, explaining approximately 35% of the inter-individual variance. Taken together, our results provide new estimates of correlation strengths, generally increasing confidence in the role of the aSPL while decreasing confidence in some of the other relationships.

  18. Estimating Wood Volume for Pinus Brutia Trees in Forest Stands from QUICKBIRD-2 Imagery

    NASA Astrophysics Data System (ADS)

    Patias, Petros; Stournara, Panagiota

    2016-06-01

    Knowledge of forest parameters, such as wood volume, is required for a sustainable forest management. Collecting such information in the field is laborious and even not feasible in inaccessible areas. In this study, tree wood volume is estimated utilizing remote sensing techniques, which can facilitate the extraction of relevant information. The study area is the University Forest of Taxiarchis, which is located in central Chalkidiki, Northern Greece and covers an area of 58km2. The tree species under study is the conifer evergreen species P. brutia (Calabrian pine). Three plot surfaces of 10m radius were used. VHR Quickbird-2 images are used in combination with an allometric relationship connecting the Tree Crown with the Diameter at breast height (Dbh), and a volume table developed for Greece. The overall methodology is based on individual tree crown delineation, based on (a) the marker-controlled watershed segmentation approach and (b) the GEographic Object-Based Image Analysis approach. The aim of the first approach is to extract separate segments each of them including a single tree and eventual lower vegetation, shadows, etc. The aim of the second approach is to detect and remove the "noisy" background. In the application of the first approach, the Blue, Green, Red, Infrared and PCA-1 bands are tested separately. In the application of the second approach, NDVI and image brightness thresholds are utilized. The achieved results are evaluated against field plot data. Their observed difference are between -5% to +10%.

  19. Subcutaneous nerve activity is more accurate than the heart rate variability in estimating cardiac sympathetic tone in ambulatory dogs with myocardial infarction

    PubMed Central

    Chan, Yi-Hsin; Tsai, Wei-Chung; Shen, Changyu; Han, Seongwook; Chen, Lan S.; Lin, Shien-Fong; Chen, Peng-Sheng

    2015-01-01

    Background We recently reported that subcutaneous nerve activity (SCNA) can be used to estimate sympathetic tone. Objectives To test the hypothesis that left thoracic SCNA is more accurate than heart rate variability (HRV) in estimating cardiac sympathetic tone in ambulatory dogs with myocardial infarction (MI). Methods We used an implanted radiotransmitter to study left stellate ganglion nerve activity (SGNA), vagal nerve activity (VNA), and thoracic SCNA in 9 dogs at baseline and up to 8 weeks after MI. HRV was determined based by time-domain, frequency-domain and non-linear analyses. Results The correlation coefficients between integrated SGNA and SCNA averaged 0.74 (95% confidence interval (CI), 0.41–1.06) at baseline and 0.82 (95% CI, 0.63–1.01) after MI (P<.05 for both). The absolute values of the correlation coefficients were significant larger than that between SGNA and HRV analysis based on time-domain, frequency-domain and non-linear analyses, respectively, at baseline (P<.05 for all) and after MI (P<.05 for all). There was a clear increment of SGNA and SCNA at 2, 4, 6 and 8 weeks after MI, while HRV parameters showed no significant changes. Significant circadian variations were noted in SCNA, SGNA and all HRV parameters at baseline and after MI, respectively. Atrial tachycardia (AT) episodes were invariably preceded by the SCNA and SGNA, which were progressively increased from 120th, 90th, 60th to 30th s before the AT onset. No such changes of HRV parameters were observed before AT onset. Conclusion SCNA is more accurate than HRV in estimating cardiac sympathetic tone in ambulatory dogs with MI. PMID:25778433

  20. Estimation of Residual Peritoneal Volume Using Technetium-99m Sulfur Colloid Scintigraphy.

    PubMed

    Katopodis, Konstantinos P; Fotopoulos, Andrew D; Balafa, Olga C; Tsiouris, Spyridon Th; Triandou, Eleni G; Al-Bokharhli, Jichad B; Kitsos, Athanasios C; Dounousi, Evagelia C; Siamopoulos, Konstantinos C

    2015-01-01

    Residual peritoneal volume (RPV) may contribute in the development of ultrafiltration failure in patients with normal transcapillary ultrafiltration. The aim of this study was to estimate the RPV using intraperitoneal technetium-99m Sulfur Colloid (Tc). Twenty patients on peritoneal dialysis were studied. RPV was estimated by: 1) intraperitoneal instillation of Tc (RPV-Tc) and 2) classic Twardowski calculations using endogenous solutes, such as urea (RPV-u), creatinine (RPV-cr), and albumin (RPV-alb). Each method's reproducibility was assessed in a subgroup of patients in two consecutive measurements 48 h apart. Both methods displayed reproducibility (r = 0.93, p = 0.001 for RPVTc and r = 0.90, p = 0.001 for RPV-alb) between days 1 and 2, respectively. We found a statistically significant difference between RPV-Tc and RPV-cr measurements (347.3 ± 116.7 vs. 450.0 ± 67.8 ml; p =0.001) and RPV-u (515.5 ± 49.4 ml; p < 0.001), but not with RPV-alb (400.1 ± 88.2 ml; p = 0.308). A good correlation was observed only between RPV-Tc and RPV-alb (p < 0.001). The Tc method can estimate the RPV as efficiently as the high molecular weight endogenous solute measurement method. It can also provide an imaging estimate of the intraperitoneal distribution of RPV.

  1. A rapid method for estimation of Pu-isotopes in urine samples using high volume centrifuge.

    PubMed

    Kumar, Ranjeet; Rao, D D; Dubla, Rupali; Yadav, J R

    2017-07-01

    The conventional radio-analytical technique used for estimation of Pu-isotopes in urine samples involves anion exchange/TEVA column separation followed by alpha spectrometry. This sequence of analysis consumes nearly 3-4 days for completion. Many a times excreta analysis results are required urgently, particularly under repeat and incidental/emergency situations. Therefore, there is need to reduce the analysis time for the estimation of Pu-isotopes in bioassay samples. This paper gives the details of standardization of a rapid method for estimation of Pu-isotopes in urine samples using multi-purpose centrifuge, TEVA resin followed by alpha spectrometry. The rapid method involves oxidation of urine samples, co-precipitation of plutonium along with calcium phosphate followed by sample preparation using high volume centrifuge and separation of Pu using TEVA resin. Pu-fraction was electrodeposited and activity estimated using (236)Pu tracer recovery by alpha spectrometry. Ten routine urine samples of radiation workers were analyzed and consistent radiochemical tracer recovery was obtained in the range 47-88% with a mean and standard deviation of 64.4% and 11.3% respectively. With this newly standardized technique, the whole analytical procedure is completed within 9h (one working day hour). Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. A novel optical method for estimating the near-wall volume fraction in granular flows

    NASA Astrophysics Data System (ADS)

    Sarno, Luca; Nicolina Papa, Maria; Carleo, Luigi; Tai, Yih-Chin

    2016-04-01

    Geophysical phenomena, such as debris flows, pyroclastic flows and rock avalanches, involve the rapid flow of granular mixtures. Today the dynamics of these flows is far from being deeply understood, due to their huge complexity compared to clear water or monophasic fluids. To this regard, physical models at laboratory scale represent important tools for understanding the still unclear properties of granular flows and their constitutive laws, under simplified experimental conditions. Beside the velocity and the shear rate, the volume fraction is also strongly interlinked with the rheology of granular materials. Yet, a reliable estimation of this quantity is not easy through non-invasive techniques. In this work a novel cost-effective optical method for estimating the near-wall volume fraction is presented and, then, applied to a laboratory study on steady-state granular flows. A preliminary numerical investigation, through Monte-Carlo generations of grain distributions under controlled illumination conditions, allowed to find the stochastic relationship between the near-wall volume fraction, c3D, and a measurable quantity (the two-dimensional volume fraction), c2D, obtainable through an appropriate binarization of gray-scale images captured by a camera placed in front of the transparent boundary. Such a relation can be well described by c3D = aexp(bc2D), with parameters only depending on the angle of incidence of light, ζ. An experimental validation of the proposed approach is carried out on dispersions of white plastic grains, immersed in various ambient fluids. The mixture, confined in a box with a transparent window, is illuminated by a flickering-free LED lamp, placed so as to form a given ζ with the measuring surface, and is photographed by a camera, placed in front of the same window. The predicted exponential law is found to be in sound agreement with experiments for a wide range of ζ (10° <ζ<45°). The technique is, then, applied to steady-state dry

  3. Volume estimation of tonsil phantoms using an oral camera with 3D imaging

    PubMed Central

    Das, Anshuman J.; Valdez, Tulio A.; Vargas, Jose Arbouin; Saksupapchon, Punyapat; Rachapudi, Pushyami; Ge, Zhifei; Estrada, Julio C.; Raskar, Ramesh

    2016-01-01

    Three-dimensional (3D) visualization of oral cavity and oropharyngeal anatomy may play an important role in the evaluation for obstructive sleep apnea (OSA). Although computed tomography (CT) and magnetic resonance (MRI) imaging are capable of providing 3D anatomical descriptions, this type of technology is not readily available in a clinic setting. Current imaging of the oropharynx is performed using a light source and tongue depressors. For better assessment of the inferior pole of the tonsils and tongue base flexible laryngoscopes are required which only provide a two dimensional (2D) rendering. As a result, clinical diagnosis is generally subjective in tonsillar hypertrophy where current physical examination has limitations. In this report, we designed a hand held portable oral camera with 3D imaging capability to reconstruct the anatomy of the oropharynx in tonsillar hypertrophy where the tonsils get enlarged and can lead to increased airway resistance. We were able to precisely reconstruct the 3D shape of the tonsils and from that estimate airway obstruction percentage and volume of the tonsils in 3D printed realistic models. Our results correlate well with Brodsky’s classification of tonsillar hypertrophy as well as intraoperative volume estimations. PMID:27446667

  4. Estimating the impact of high-production-volume chemicals on remote ecosystems by toxic pressure calculation.

    PubMed

    Harbers, Jasper V; Huijbregts, Mark A J; Posthuma, Leo; Van de Meent, Dik

    2006-03-01

    Although many chemicals are in use, the environmental impacts of only a few have been established, usually on per-chemical basis. Uncertainty remains about the overall impact of chemicals. This paper estimates combined toxic pressure on coastal North Sea ecosystems from 343 high-production-volume chemicals used within the catchment of rivers Rhine, Meuse, and Scheldt. Multimedia fate modeling and species sensitivity distribution-based effects estimation are applied. Calculations start from production volumes and emission rates and use physicochemical substance properties and aquatic ecotoxicity data. Parameter uncertainty is addressed by Monte Carlo simulations. Results suggest that the procedure is technically feasible. Combined toxic pressure of all 343 chemicals in coastal North Seawater is 0.025 (2.5% of the species are exposed to concentration levels above EC50 values), with a wide confidence interval of nearly 0-1. This uncertainty appears to be largely due to uncertainties in interspecies variances of aquatic toxicities and, to a lesser extent, to uncertainties in emissions and degradation rates. Due to these uncertainties, the results support gross ranking of chemicals in categories: negligible and possibly relevant contributions only. With 95% confidence, 283 of the 343 chemicals (83%) contribute negligibly (less than 0.1%) to overall toxic pressure, and only 60 (17%) need further consideration.

  5. Limitations of Stroke Volume Estimation by Non-Invasive Blood Pressure Monitoring in Hypergravity

    PubMed Central

    2015-01-01

    Background Altitude and gravity changes during aeromedical evacuations induce exacerbated cardiovascular responses in unstable patients. Non-invasive cardiac output monitoring is difficult to perform in this environment with limited access to the patient. We evaluated the feasibility and accuracy of stroke volume estimation by finger photoplethysmography (SVp) in hypergravity. Methods Finger arterial blood pressure (ABP) waveforms were recorded continuously in ten healthy subjects before, during and after exposure to +Gz accelerations in a human centrifuge. The protocol consisted of a 2-min and 8-min exposure up to +4 Gz. SVp was computed from ABP using Liljestrand, systolic area, and Windkessel algorithms, and compared with reference values measured by echocardiography (SVe) before and after the centrifuge runs. Results The ABP signal could be used in 83.3% of cases. After calibration with echocardiography, SVp changes did not differ from SVe and values were linearly correlated (p<0.001). The three algorithms gave comparable SVp. Reproducibility between SVp and SVe was the best with the systolic area algorithm (limits of agreement −20.5 and +38.3 ml). Conclusions Non-invasive ABP photoplethysmographic monitoring is an interesting technique to estimate relative stroke volume changes in moderate and sustained hypergravity. This method may aid physicians for aeronautic patient monitoring. PMID:25798613

  6. Solid volume fraction estimation of bone:marrow replica models using ultrasound transit time spectroscopy.

    PubMed

    Wille, Marie-Luise; Langton, Christian M

    2016-02-01

    The acceptance of broadband ultrasound attenuation (BUA) for the assessment of osteoporosis suffers from a limited understanding of both ultrasound wave propagation through cancellous bone and its exact dependence upon the material and structural properties. It has recently been proposed that ultrasound wave propagation in cancellous bone may be described by a concept of parallel sonic rays; the transit time of each ray defined by the proportion of bone and marrow propagated. A Transit Time Spectrum (TTS) describes the proportion of sonic rays having a particular transit time, effectively describing the lateral inhomogeneity of transit times over the surface aperture of the receive ultrasound transducer. The aim of this study was to test the hypothesis that the solid volume fraction (SVF) of simplified bone:marrow replica models may be reliably estimated from the corresponding ultrasound transit time spectrum. Transit time spectra were derived via digital deconvolution of the experimentally measured input and output ultrasonic signals, and compared to predicted TTS based on the parallel sonic ray concept, demonstrating agreement in both position and amplitude of spectral peaks. Solid volume fraction was calculated from the TTS; agreement between true (geometric calculation) with predicted (computer simulation) and experimentally-derived values were R(2)=99.9% and R(2)=97.3% respectively. It is therefore envisaged that ultrasound transit time spectroscopy (UTTS) offers the potential to reliably estimate bone mineral density and hence the established T-score parameter for clinical osteoporosis assessment.

  7. Limitations of stroke volume estimation by non-invasive blood pressure monitoring in hypergravity.

    PubMed

    Manen, Olivier; Dussault, Caroline; Sauvet, Fabien; Montmerle-Borgdorff, Stéphanie

    2015-01-01

    Altitude and gravity changes during aeromedical evacuations induce exacerbated cardiovascular responses in unstable patients. Non-invasive cardiac output monitoring is difficult to perform in this environment with limited access to the patient. We evaluated the feasibility and accuracy of stroke volume estimation by finger photoplethysmography (SVp) in hypergravity. Finger arterial blood pressure (ABP) waveforms were recorded continuously in ten healthy subjects before, during and after exposure to +Gz accelerations in a human centrifuge. The protocol consisted of a 2-min and 8-min exposure up to +4 Gz. SVp was computed from ABP using Liljestrand, systolic area, and Windkessel algorithms, and compared with reference values measured by echocardiography (SVe) before and after the centrifuge runs. The ABP signal could be used in 83.3% of cases. After calibration with echocardiography, SVp changes did not differ from SVe and values were linearly correlated (p<0.001). The three algorithms gave comparable SVp. Reproducibility between SVp and SVe was the best with the systolic area algorithm (limits of agreement -20.5 and +38.3 ml). Non-invasive ABP photoplethysmographic monitoring is an interesting technique to estimate relative stroke volume changes in moderate and sustained hypergravity. This method may aid physicians for aeronautic patient monitoring.

  8. Estimating cardiac fiber orientations in pig hearts using registered ultrasound and MR image volumes

    NASA Astrophysics Data System (ADS)

    Dormer, James D.; Meng, Yuguang; Zhang, Xiaodong; Jiang, Rong; Wagner, Mary B.; Fei, Baowei

    2017-03-01

    Heart fiber mechanics can be important predictors in current and future cardiac function. Accurate knowledge of these mechanics could enable cardiologists to provide a diagnosis before conditions progress. Magnetic resonance diffusion tensor imaging (MR-DTI) has been used to determine cardiac fiber orientations. Ultrasound is capable of providing anatomical information in real time, enabling a physician to quickly adjust parameters to optimize image scans. If known fiber orientations from a template heart measured using DTI can be accurately deformed onto a cardiac ultrasound volume, fiber orientations could be estimated for the patient without the need for a costly MR scan while still providing cardiologists valuable information about the heart mechanics. In this study, we apply the method to pig hearts, which are a close representation of human heart anatomy. Experiments from pig hearts show that the registration method achieved an average Dice similarity coefficient (DSC) of 0.819 +/- 0.050 between the ultrasound and deformed MR volumes and that the proposed ultrasound-based method is able to estimate the cardiac fiber orientation in pig hearts.

  9. Semi-automatic border detection method for left ventricular volume estimation in 4D ultrasound data

    NASA Astrophysics Data System (ADS)

    van Stralen, Marijn; Bosch, Johan G.; Voormolen, Marco M.; van Burken, Gerard; Krenning, Boudewijn J.; van Geuns, Robert Jan M.; Angelie, Emmanuelle; van der Geest, Rob J.; Lancee, Charles T.; de Jong, Nico; Reiber, Johan H. C.

    2005-04-01

    We propose a semi-automatic endocardial border detection method for LV volume estimation in 3D time series of cardiac ultrasound data. It is based on pattern matching and dynamic programming techniques and operates on 2D slices of the 4D data requiring minimal user-interaction. We evaluated on data acquired with the Fast Rotating Ultrasound (FRU) transducer: a linear phased array transducer rotated at high speed around its image axis, generating high quality 2D images of the heart. We automatically select a subset of 2D images at typically 10 rotation angles and 16 cardiac phases. From four manually drawn contours a 4D shape model and a 4D edge pattern model is derived. For the selected images, contour shape and edge patterns are estimated using the models. Pattern matching and dynamic programming is applied to detect the contours automatically. The method allows easy corrections in the detected 2D contours, to iteratively achieve more accurate models and improved detections. An evaluation of this method on FRU data against MRI was done for full cycle LV volumes on 10 patients. Good correlations were found against MRI volumes (r=0.94, y=0.72x + 30.3, difference of 9.6 +/- 17.4 ml (Av +/- SD) ) and a low interobserver variability for US (r=0.94, y=1.11x - 16.8, difference of 1.4 +/- 14.2 ml). On average only 2.8 corrections per patient were needed (in a total of 160 images). Although the method shows good correlations with MRI without corrections, applying these corrections can make significant improvements.

  10. Accuracy estimation for projection-to-volume targeting during rotational therapy: A feasibility study.

    PubMed

    Long, Yong; Fessler, Jeffrey A; Balter, James M

    2010-06-01

    Estimating motion and deformation parameters from a series of projection radiographs acquired during arc therapy using a reference CT volume has become a promising technique for targeting treatment. The purpose of this work is to investigate the influence of rotational arc length on maximum achievable accuracy of motion estimation. The projection-to-volume alignment procedure used a nonrigid model to describe motion in thorax area, a cost function consisting of a least-squared error metric and a simple regularizer that encourages local invertibility, and a four-level multiresolution scheme with a conjugate gradient method to optimize the cost function. The authors tested both small and large scale deformations typically found in the thorax of a radiotherapy patient at different breathing states and limited-angle scans of six angular widths (12°, 18°, 24°, 36°, 60°, and 90°) centered at three angles (0°, 45°, and 90°). The experiments illustrate the potential accuracy of limited-angle projection-to-volume alignment. Registration accuracy can be sensitive to angular center, tends to be lower along direction of the projection set, and tends to decrease away from the rotation center. The studies of small as well as large but realistically scaled deformations show similar dependencies. These trends appear to have fairly low sensitivity to quantum noise effects. There is potentially sufficient information present in a small spread of projections to monitor the configuration of reasonably high contrast tumors without implanted markers. © 2010 American Association of Physicists in Medicine.

  11. Acute effects of delayed reperfusion following myocardial infarction: a 3D x-ray imaging analysis

    NASA Astrophysics Data System (ADS)

    Simari, Robert D.; Bell, M. R.; Pao, Y. C.; Gersh, B. J.; Ritman, Erik L.

    1996-04-01

    Clinical and experimental data suggest that delayed reperfusion of the infarct related artery may limit infarct expansion without increasing myocardial salvage. In order to assess the potential mechanisms involved, an acute closed chest canine model of myocardial infarction and delayed reperfusion was studied. Nineteen dogs underwent 3D computed tomography in the Dynamic Spatial Reconstructor (a fast, volume imaging, CT scanner) at baseline and three and four hours later to estimate left ventricular chamber volumes, global distensibility and regional myocardial stiffness. A control group was scanned without intervention. An occlusion group underwent four hours of coronary artery occlusion. A reperfusion group underwent three hours of coronary artery occlusion followed by one hour of reperfusion. Similar infarct sizes were seen in the occlusion and reperfusion groups. Globally reperfusion was associated with increased left ventricular end diastolic pressure and prolongation of global relaxation. Regionally reperfusion was associated with increased myocardial stiffness, intramyocardial blood volume and wall thickness within the infarct zone relative to the not reperfused myocardium.

  12. Partial volume correction of brain perfusion estimates using the inherent signal data of time-resolved arterial spin labeling.

    PubMed

    Ahlgren, André; Wirestam, Ronnie; Petersen, Esben Thade; Ståhlberg, Freddy; Knutsson, Linda

    2014-09-01

    Quantitative perfusion MRI based on arterial spin labeling (ASL) is hampered by partial volume effects (PVEs), arising due to voxel signal cross-contamination between different compartments. To address this issue, several partial volume correction (PVC) methods have been presented. Most previous methods rely on segmentation of a high-resolution T1 -weighted morphological image volume that is coregistered to the low-resolution ASL data, making the result sensitive to errors in the segmentation and coregistration. In this work, we present a methodology for partial volume estimation and correction, using only low-resolution ASL data acquired with the QUASAR sequence. The methodology consists of a T1 -based segmentation method, with no spatial priors, and a modified PVC method based on linear regression. The presented approach thus avoids prior assumptions about the spatial distribution of brain compartments, while also avoiding coregistration between different image volumes. Simulations based on a digital phantom as well as in vivo measurements in 10 volunteers were used to assess the performance of the proposed segmentation approach. The simulation results indicated that QUASAR data can be used for robust partial volume estimation, and this was confirmed by the in vivo experiments. The proposed PVC method yielded probable perfusion maps, comparable to a reference method based on segmentation of a high-resolution morphological scan. Corrected gray matter (GM) perfusion was 47% higher than uncorrected values, suggesting a significant amount of PVEs in the data. Whereas the reference method failed to completely eliminate the dependence of perfusion estimates on the volume fraction, the novel approach produced GM perfusion values independent of GM volume fraction. The intra-subject coefficient of variation of corrected perfusion values was lowest for the proposed PVC method. As shown in this work, low-resolution partial volume estimation in connection with ASL perfusion

  13. Validity of Acute Stroke Lesion Volume Estimation by Diffusion-Weighted Imaging–Alberta Stroke Program Early Computed Tomographic Score Depends on Lesion Location in 496 Patients With Middle Cerebral Artery Stroke

    PubMed Central

    Schröder, Julian; Cheng, Bastian; Ebinger, Martin; Köhrmann, Martin; Wu, Ona; Kang, Dong-Wha; Liebeskind, David S.; Tourdias, Thomas; Singer, Oliver C.; Christensen, Soren; Campbell, Bruce; Luby, Marie; Warach, Steven; Fiehler, Jens; Fiebach, Jochen B.; Gerloff, Christian; Thomalla, Götz

    2016-01-01

    Background and Purpose Alberta Stroke Program Early Computed Tomographic Score (ASPECTS) has been used to estimate diffusion-weighted imaging (DWI) lesion volume in acute stroke. We aimed to assess correlations of DWI-ASPECTS with lesion volume in different middle cerebral artery (MCA) subregions and reproduce existing ASPECTS thresholds of a malignant profile defined by lesion volume ≥100 mL. Methods We analyzed data of patients with MCA stroke from a prospective observational study of DWI and fluid-attenuated inversion recovery in acute stroke. DWI-ASPECTS and lesion volume were calculated. The population was divided into subgroups based on lesion localization (superficial MCA territory, deep MCA territory, or both). Correlation of ASPECTS and infarct volume was calculated, and receiver-operating characteristics curve analysis was performed to identify the optimal ASPECTS threshold for ≥100-mL lesion volume. Results A total of 496 patients were included. There was a significant negative correlation between ASPECTS and DWI lesion volume (r=−0.78; P<0.0001). With regards to lesion localization, correlation was weaker in deep MCA region (r=−0.19; P=0.038) when compared with superficial (r=−0.72; P<0.001) or combined superficial and deep MCA lesions (r=−0.72; P<0.001). Receiver-operating characteristics analysis revealed ASPECTS≤6 as best cutoff to identify ≥100-mL DWI lesion volume; however, positive predictive value was low (0.35). Conclusions ASPECTS has limitations when lesion location is not considered. Identification of patients with malignant profile by DWI-ASPECTS may be unreliable. ASPECTS may be a useful tool for the evaluation of noncontrast computed tomography. However, if MRI is used, ASPECTS seems dispensable because lesion volume can easily be quantified on DWI maps. PMID:25316278

  14. Validity of acute stroke lesion volume estimation by diffusion-weighted imaging-Alberta Stroke Program Early Computed Tomographic Score depends on lesion location in 496 patients with middle cerebral artery stroke.

    PubMed

    Schröder, Julian; Cheng, Bastian; Ebinger, Martin; Köhrmann, Martin; Wu, Ona; Kang, Dong-Wha; Liebeskind, David S; Tourdias, Thomas; Singer, Oliver C; Christensen, Soren; Campbell, Bruce; Luby, Marie; Warach, Steven; Fiehler, Jens; Fiebach, Jochen B; Gerloff, Christian; Thomalla, Götz

    2014-12-01

    Alberta Stroke Program Early Computed Tomographic Score (ASPECTS) has been used to estimate diffusion-weighted imaging (DWI) lesion volume in acute stroke. We aimed to assess correlations of DWI-ASPECTS with lesion volume in different middle cerebral artery (MCA) subregions and reproduce existing ASPECTS thresholds of a malignant profile defined by lesion volume ≥100 mL. We analyzed data of patients with MCA stroke from a prospective observational study of DWI and fluid-attenuated inversion recovery in acute stroke. DWI-ASPECTS and lesion volume were calculated. The population was divided into subgroups based on lesion localization (superficial MCA territory, deep MCA territory, or both). Correlation of ASPECTS and infarct volume was calculated, and receiver-operating characteristics curve analysis was performed to identify the optimal ASPECTS threshold for ≥100-mL lesion volume. A total of 496 patients were included. There was a significant negative correlation between ASPECTS and DWI lesion volume (r=-0.78; P<0.0001). With regards to lesion localization, correlation was weaker in deep MCA region (r=-0.19; P=0.038) when compared with superficial (r=-0.72; P<0.001) or combined superficial and deep MCA lesions (r=-0.72; P<0.001). Receiver-operating characteristics analysis revealed ASPECTS≤6 as best cutoff to identify ≥100-mL DWI lesion volume; however, positive predictive value was low (0.35). ASPECTS has limitations when lesion location is not considered. Identification of patients with malignant profile by DWI-ASPECTS may be unreliable. ASPECTS may be a useful tool for the evaluation of noncontrast computed tomography. However, if MRI is used, ASPECTS seems dispensable because lesion volume can easily be quantified on DWI maps. © 2014 American Heart Association, Inc.

  15. Effect of hospital case volume on treatment and in-hospital outcomes in patients undergoing percutaneous coronary intervention for acute myocardial infarction. Results from the Ibaraki Coronary Artery Disease Study (ICAS) Registry.

    PubMed

    Ohtsuka Machino, Tomoko; Toyama, Masahiro; Obara, Kenichi; Takeyasu, Noriyuki; Watanabe, Shigeyuki; Aonuma, Kazutaka

    2008-05-01

    The volume of percutaneous coronary interventions (PCI) performed in a hospital has been suggested to correlate with favorable outcomes in patients undergoing primary PCI for acute myocardial infarction (AMI). However, studies that use current data and compare treatment and outcomes for AMI among hospitals with different volumes are still limited in Japan. Between January 2004 and March 2006, 401 AMI patients underwent primary PCI in the 11 hospitals participating in the Ibaraki Coronary Artery Disease Study (ICAS). Clinical characteristics, treatment, and in-hospital outcomes were retrospectively compared between 254 patients admitted to high-volume PCI hospitals and 147 patients admitted to low-volume hospitals. Low-volume hospitals had a higher prevalence of multivessel disease patients. High-volume hospitals had longer onset-to-door times, which were offset by faster door-to-balloon times. Rates of coronary stent use and successful PCI were comparable between the groups. Low-volume hospitals more frequently performed intra-aortic balloon pumping. Length of stay was longer in low-volume hospitals, whereas in-hospital mortality, bypass surgery, and repeat PCI rates did not differ between groups. Although the present study assessed limited data based on small sample size, we observed that contemporary standard treatments including stent implantation were performed for AMI patients undergoing primary PCI in hospitals with both high and low case volumes. We did not find an obvious relationship between hospital PCI volume and in-hospital outcomes in our data. However, further prospective surveys should be attempted to confirm these results.

  16. Edaravone, a free radical scavenger, attenuates cerebral infarction and hemorrhagic infarction in rats with hyperglycemia.

    PubMed

    Okamura, Koichi; Tsubokawa, Tamiji; Johshita, Hiroo; Miyazaki, Hiroshi; Shiokawa, Yoshiaki

    2014-01-01

    Thrombolysis due to acute ischemic stroke is associated with the risk of hemorrhagic infarction, especially after reperfusion. Recent experimental studies suggest that the main mechanism contributing to hemorrhagic infarction is oxidative stress caused by disruption of the blood-brain barrier. Edaravone, a free radical scavenger, decreases oxidative stress, thereby preventing hemorrhagic infarction during ischemia and reperfusion. In this study, we investigated the effects of edaravone on hemorrhagic infarction in a rat model of hemorrhagic transformation. We used a previously established hemorrhagic transformation model of rats with hyperglycemia. Hyperglycemia was induced by intraperitoneal injection of glucose to all rats (n  =  20). The rats with hyperglycemia showed a high incidence of hemorrhagic infarction. Middle cerebral artery occlusion (MCAO) for 1.5 hours followed by reperfusion for 24 hours was performed in edaravone-treated rats (n  =  10) and control rats (n  =  10). Upon completion of reperfusion, both groups were evaluated for infarct size and hemorrhage volume and the results obtained were compared. Edaravone significantly decreased infarct volume, with the average infarct volume in the edaravone-treated rats (227.6 mm(3)) being significantly lower than that in the control rats (264.0 mm(3)). Edaravone treatment also decreased the postischemic hemorrhage volumes (53.4 mm(3) in edaravone-treated rats vs 176.4 mm(3) in controls). In addition, the ratio of hemorrhage volume to infarct volume was lower in the edaravone-treated rats (23.5%) than in the untreated rats (63.2%). Edaravone attenuates cerebral infarction and hemorrhagic infarction in rats with hyperglycemia.

  17. Volume of water equivalent estimates in Central Chilean glaciers, derived from airborne radar surveys

    NASA Astrophysics Data System (ADS)

    Oberreuter, J.; Gacitúa, G.; Uribe, J.; Rivera, A.; Zamora, R.; Loriaux, T.

    2013-12-01

    Central Chilean glaciers (33-35°S) are an important melt water resource for human consumption, agriculture, mining and industrial activities in this, the most populated region of the country. These glaciers have been retreating and shrinking during recent decades, in response to ongoing climatic changes. As a result, there is increasing concern about future water availability especially during dry summers, when glaciers are thought to have the maximum contribution to runoff. In spite of their importance, very little is known about the total volume of water equivalent storage in these glaciers. In order to improve our knowledge about this issue, we have utilized a new airborne radar system, which was developed at CECs, specially designed to penetrate temperate and cold ice, which is working at central frequencies between 20 and 60 MHz, depending on the penetration range capacity at each glacier. This system has been installed on helicopters, where the metal structure antenna (receptor and transmitter) is carried as a hanging load while flying along pre designated tracks, enabling to survey steep and remote glacier areas, many of them without any ice thickness data up to date. The helicopter is geo-located using dual frequency GPS receivers and an inertial navigation unit installed onboard, and each measurement is geo referenced using a pointing laser located at the radar antenna. The antenna must be flown at 40 m above the glacier surface at an air speed of 40 knots. This system has been successfully used on 24 glaciers representing 16% of the total glacier area of the Aconcagua, Maipo and Rapel basins. A mean ice thickness of 168 m and a maximum of 342 m were detected among the surveyed glaciers. Crossing points between overlapping surveyed tracks resulted in mean differences of near 20 m (less than 10% of the total ice thickness). Subsequent ice volumes were calculated by interpolating radar data collected along tracks. These volumetric estimations correlated

  18. [Application of diffusion tensor imaging in judging infarction time of acute ischemic cerebral infarction].

    PubMed

    Dai, Zhenyu; Chen, Fei; Yao, Lizheng; Dong, Congsong; Liu, Yang; Shi, Haicun; Zhang, Zhiping; Yang, Naizhong; Zhang, Mingsheng; Dai, Yinggui

    2015-08-18

    To evaluate the clinical application value of diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) in judging infarction time phase of acute ischemic cerebral infarction. To retrospective analysis DTI images of 52 patients with unilateral acute ischemic cerebral infarction (hyper-acute, acute and sub-acute) from the Affiliated Yancheng Hospital of Southeast University Medical College, which diagnosed by clinic and magnetic resonance imaging. Set the regions of interest (ROIs) of infarction lesions, brain tissue close to infarction lesions and corresponding contra (contralateral normal brain tissue) on DTI parameters mapping of fractional anisotropy (FA), volume ratio anisotropy (VRA), average diffusion coefficient (DCavg) and exponential attenuation (Exat), record the parameters values of ROIs and calculate the relative parameters value of infarction lesion to contra. Meanwhile, reconstruct the DTT images based on the seed points (infarction lesion and contra). The study compared each parameter value of infarction lesions, brain tissue close to infarction lesions and corresponding contra, also analysed the differences of relative parameters values in different infarction time phases. The DTT images of acute ischemic cerebral infarction in each time phase could show the manifestation of fasciculi damaged. The DCavg value of cerebral infarction lesions was lower and the Exat value was higher than contra in each infarction time phase (P<0.05). The FA and VRA value of cerebral infarction lesions were reduced than contra only in acute and sub-acute infarction (P<0.05). The FA, VRA and Exat value of brain tissue close to infarction lesions were increased and DCavg value was decreased than contra in hyper-acute infarction (P<0.05). There were no statistic differences of FA, VRA, DCavg and Exat value of brain tissue close to infarction lesions in acute and sub-acute infarction. The relative FA and VRA value of infarction lesion to contra gradually

  19. Correcting Partial Volume Effect in Bi-exponential T2 Estimation of Small Lesions

    PubMed Central

    Huang, Chuan; Galons, Jean-Philippe; Graff, Christian G.; Clarkson, Eric W.; Bilgin, Ali; Kalb, Bobby; Martin, Diego R.; Altbach, Maria I.

    2014-01-01

    Purpose T2 mapping provides a quantitative approach for focal liver lesion characterization. For small lesions a bi-exponential model should be used to account for partial volume effects (PVE). However, conventional bi-exponential fitting suffers from large uncertainty of the fitted parameters when noise is present. The purpose of this work is to develop a more robust method to correct for PVE affecting small lesions. Methods We developed a ROI-based joint bi-exponential fitting (JBF) algorithm to estimate the T2 of lesions affected by PVE. JBF takes advantage of the lesion fraction variation among voxels within an ROI. JBF is compared to conventional approaches using Cramér-Rao lower bound analysis, numerical simulations, phantom and -vivo data. Results JBF provides more accurate and precise T2 estimates in the presence of PVE. Furthermore, JBF is less sensitive to ROI drawing. Phantom and in-vivo results show that JBF can be combined with a reconstruction method for highly undersampled data, enabling the characterization of small abdominal lesions from data acquired in a single breath-hold. Conclusion The JBF algorithm provides more accurate and stable T2 estimates for small structures than conventional techniques when PVE is present. It should be particularly useful for the characterization of small abdominal lesions. PMID:24753061

  20. Comparative reliability analysis of publicly available software packages for automatic intracranial volume estimation.

    PubMed

    Sargolzaei, S; Goryawala, M; Cabrerizo, M; Chen, G; Jayakar, P; Duara, R; Barker, W; Adjouadi, M

    2014-01-01

    Intracranial volume is an important measure in brain research often used as a correction factor in inter subject studies. The current study investigates the resulting outcome in terms of the type of software used for automatically estimating ICV measure. Five groups of 70 subjects are considered, including adult controls (AC) (n=11), adult with dementia (AD) (n=11), pediatric controls (PC) (n=18) and two groups of pediatric epilepsy subjects (PE1.5 and PE3) (n=30) using 1.5 T and 3T scanners, respectively. Reference measurements were calculated for each subject by manually tracing intracranial cavity without sub-sampling. Four publicly available software packages (AFNI, Freesurfer, FSL, and SPM) were examined in their ability to automatically estimate ICV across the five groups. Linear regression analyses suggest that reference measurement discrepancy could be explained best by SPM [R(2)= 0.67;p <; 0.01] for the AC group, Freesurfer [R(2) = 0.46; p = 0.02] for the AD group, AFNI [R(2)=0.97;p<; 0.01] for the PC group and FSL [R(2) = 0.6; p = 0.1] for the PE1.5 and [R(2) = 0.6; p <; 0.01] for PE3 groups. The study demonstrates that the choice of the automated software for ICV estimation is dependent on the population under consideration and whether the software used is atlas-based or not.

  1. Sex Estimation from Human Cranium: Forensic and Anthropological Interest of Maxillary Sinus Volumes.

    PubMed

    Radulesco, Thomas; Michel, Justin; Mancini, Julien; Dessi, Patrick; Adalian, Pascal

    2017-08-23

    Sex estimation is a key objective of forensic science. We aimed to establish whether maxillary sinus volumes (MSV) could assist in estimating an individual's sex. One hundred and three CT scans were included. MSV were determined using three-dimensional reconstructions. Two observers performed three-dimensional MSV reconstructions using the same methods. Intra- and interobserver reproducibility were statistically compared using the intraclass correlation coefficient (ICC) (α = 5%). Both intra- and interobserver reproducibility were perfect regarding MSV; both ICCs were 100%. There were no significant differences between right and left MSV (p = 0.083). No correlation was found between age and MSV (p > 0.05). We demonstrated the existence of sexual dimorphism in MSV (p < 0.001) and showed that MSV measurements gave a 68% rate of correct allocations to sex group. MSV measurements could be useful to support sex estimation in forensic medicine. © 2017 American Academy of Forensic Sciences.

  2. Methods and equations for estimating aboveground volume, biomass, and carbon for trees in the U.S. forest inventory, 2010

    Treesearch

    Christopher W. Woodall; Linda S. Heath; Grant M. Domke; Michael C. Nichols

    2011-01-01

    The U.S. Forest Service, Forest Inventory and Analysis (FIA) program uses numerous models and associated coefficients to estimate aboveground volume, biomass, and carbon for live and standing dead trees for most tree species in forests of the United States. The tree attribute models are coupled with FIA's national inventory of sampled trees to produce estimates of...

  3. Location of Acute Infarcts and Agitation and Aggression in Stroke.

    PubMed

    Tang, Wai Kwong; Liu, Xiang Xin; Liang, Huajun; Chen, Yang Kun; Chu, Winnie Chiu Wing; Ahuja, Anil T; Abrigo, Jill; Mok, Vincent Chung Tong; Ungvari, Gabor S; Wong, Ka Sing; Spalletta, Gianfranco

    2017-01-01

    The role of the infarct location in the development of poststroke agitation (PSA) is largely unknown. This study examined the association between the locations of infarcts and PSA at 9 months following the index stroke in 213 patients with the Chinese version of the Neuropsychiatric Inventory. Compared with the non-PSA group, PSA patients had a higher number and volume of acute pontine infarcts. Ventral pontine and lateral cerebellar infarcts were independent predictors of PSA in the multivariate analysis.

  4. Kidney Stone Volume Estimation from Computerized Tomography Images Using a Model Based Method of Correcting for the Point Spread Function

    PubMed Central

    Duan, Xinhui; Wang, Jia; Qu, Mingliang; Leng, Shuai; Liu, Yu; Krambeck, Amy; McCollough, Cynthia

    2014-01-01

    Purpose We propose a method to improve the accuracy of volume estimation of kidney stones from computerized tomography images. Materials and Methods The proposed method consisted of 2 steps. A threshold equal to the average of the computerized tomography number of the object and the background was first applied to determine full width at half maximum volume. Correction factors were then applied, which were precalculated based on a model of a sphere and a 3-dimensional Gaussian point spread function. The point spread function was measured in a computerized tomography scanner to represent the response of the scanner to a point-like object. Method accuracy was validated using 6 small cylindrical phantoms with 2 volumes of 21.87 and 99.9 mm3, and 3 attenuations, respectively, and 76 kidney stones with a volume range of 6.3 to 317.4 mm3. Volumes estimated by the proposed method were compared with full width at half maximum volumes. Results The proposed method was significantly more accurate than full width at half maximum volume (p <0.0001). The magnitude of improvement depended on stone volume with smaller stones benefiting more from the method. For kidney stones 10 to 20 mm3 in volume the average improvement in accuracy was the greatest at 19.6%. Conclusions The proposed method achieved significantly improved accuracy compared with threshold methods. This may lead to more accurate stone management. PMID:22819107

  5. Using LiDAR to Estimate Surface Erosion Volumes within the Post-storm 2012 Bagley Fire

    NASA Astrophysics Data System (ADS)

    Mikulovsky, R. P.; De La Fuente, J. A.; Mondry, Z. J.

    2014-12-01

    The total post-storm 2012 Bagley fire sediment budget of the Squaw Creek watershed in the Shasta-Trinity National Forest was estimated using many methods. A portion of the budget was quantitatively estimated using LiDAR. Simple workflows were designed to estimate the eroded volume's of debris slides, fill failures, gullies, altered channels and streams. LiDAR was also used to estimate depositional volumes. Thorough manual mapping of large erosional features using the ArcGIS 10.1 Geographic Information System was required as these mapped features determined the eroded volume boundaries in 3D space. The 3D pre-erosional surface for each mapped feature was interpolated based on the boundary elevations. A surface difference calculation was run using the estimated pre-erosional surfaces and LiDAR surfaces to determine volume of sediment potentially delivered into the stream system. In addition, cross sections of altered channels and streams were taken using stratified random selection based on channel gradient and stream order respectively. The original pre-storm surfaces of channel features were estimated using the cross sections and erosion depth criteria. Open source software Inkscape was used to estimate cross sectional areas for randomly selected channel features and then averaged for each channel gradient and stream order classes. The average areas were then multiplied by the length of each class to estimate total eroded altered channel and stream volume. Finally, reservoir and in-channel depositional volumes were estimated by mapping channel forms and generating specific reservoir elevation zones associated with depositional events. The in-channel areas and zones within the reservoir were multiplied by estimated and field observed sediment thicknesses to attain a best guess sediment volume. In channel estimates included re-occupying stream channel cross sections established before the fire. Once volumes were calculated, other erosion processes of the Bagley

  6. 3-D volume reconstruction of skin lesions for melanin and blood volume estimation and lesion severity analysis.

    PubMed

    D'Alessandro, Brian; Dhawan, Atam P

    2012-11-01

    Subsurface information about skin lesions, such as the blood volume beneath the lesion, is important for the analysis of lesion severity towards early detection of skin cancer such as malignant melanoma. Depth information can be obtained from diffuse reflectance based multispectral transillumination images of the skin. An inverse volume reconstruction method is presented which uses a genetic algorithm optimization procedure with a novel population initialization routine and nudge operator based on the multispectral images to reconstruct the melanin and blood layer volume components. Forward model evaluation for fitness calculation is performed using a parallel processing voxel-based Monte Carlo simulation of light in skin. Reconstruction results for simulated lesions show excellent volume accuracy. Preliminary validation is also done using a set of 14 clinical lesions, categorized into lesion severity by an expert dermatologist. Using two features, the average blood layer thickness and the ratio of blood volume to total lesion volume, the lesions can be classified into mild and moderate/severe classes with 100% accuracy. The method therefore has excellent potential for detection and analysis of pre-malignant lesions.

  7. Vascular endothelial growth factor gene-transferred bone marrow stromal cells engineered with a herpes simplex virus type 1 vector can improve neurological deficits and reduce infarction volume in rat brain ischemia.

    PubMed

    Miki, Yoshihito; Nonoguchi, Naosuke; Ikeda, Naokado; Coffin, Robert S; Kuroiwa, Toshihiko; Miyatake, Shin-ichi

    2007-09-01

    Several reports recently suggested that vascular endothelial growth factor (VEGF) may have a therapeutic benefit against experimental cerebral infarction animal models. In addition, bone marrow stromal cells (BMSCs) are known to have therapeutic potency in improving neurological deficits after occlusive cerebrovascular diseases. In the present study, we evaluated the hypothesis that intracerebral transplantation of VEGF gene-transferred BMSCs could provide a greater therapeutic effect than intracerebral transplantation of native (non-gene-transformed) BMSCs by using a transient middle cerebral artery occlusion (MCAO) rat model. Adult Wistar rats (Japan SLC, Inc., Hamamatsu, Japan) were anesthetized. VEGF gene-transferred BMSCs engineered with a replication-deficient herpes simplex virus type 1 1764/4-/pR19-hVEGF165 vector, native BMSCs, or phosphate-buffered saline were administered intracerebrally 24 hours after transient MCAO. All animals underwent behavioral testing for 28 days, and the infarction volume was determined 14 days after MCAO. The brain water contents in the ipsilateral and contralateral hemispheres of the MCAO were measured 2 and 7 days after the MCAO. Fourteen days after MCAO, immunohistochemical staining for VEGF was performed. The group receiving VEGF-modified BMSCs demonstrated significant functional recovery compared with those receiving native BMSCs. Fourteen days after the MCAO, there was a significantly lower infarct volume without aggravating cerebral edema in the group treated with VEGF gene-modified BMSCs compared with the control groups. The transplanted VEGF gene-modified BMSCs strongly expressed VEGF protein for at least 14 days. Our data suggest that the intracerebral transplantation of VEGF gene-transferred BMSCs may provide a more potent autologous cell transplantation therapy for stroke than the transplantation of native BMSCs alone.

  8. MCNP ESTIMATE OF THE SAMPLED VOLUME IN A NON-DESTRUCTIVE IN SITU SOIL CARBON ANALYSIS.

    SciTech Connect

    WIELOPOLSKI, L.; DIOSZEGI, I.; MITRA, S.

    2004-05-03

    Global warming, promoted by anthropogenic CO{sub 2} emission into the atmosphere, is partially mitigated by the photosynthesis processes of the terrestrial echo systems that act as atmospheric CO{sub 2} scrubbers and sequester carbon in soil. Switching from till to no till soils management practices in agriculture further augments this process. Carbon sequestration is also advanced by putting forward a carbon ''credit'' system whereby these can be traded between CO{sub 2} producers and sequesters. Implementation of carbon ''credit'' trade will be further promulgated by recent development of a non-destructive in situ carbon monitoring system based on inelastic neutron scattering (INS). Volumes and depth distributions defined by the 0.1, 1.0, 10, 50, and 90 percent neutron isofluxes, from a point source located at either 5 or 30 cm above the surface, were estimated using Monte Carlo calculations.

  9. Water volume estimates of the Greenland Perennial Firn Aquifer from in situ measurements

    NASA Astrophysics Data System (ADS)

    Koenig, L.; Miege, C.; Forster, R. R.; Brucker, L.

    2013-12-01

    Improving our understanding of the complex Greenland hydrologic system is necessary for assessing change across the Greenland Ice Sheet and its contribution to sea level rise (SLR). A new component of the Greenland hydrologic system, a Perennial Firn Aquifer (PFA), was recently discovered in April 2011. The PFA represents a large storage of liquid water within the Greenland Ice Sheet with an area of 70,000 × 10,000 km2 simulated by the RACMO2/GR regional climate model which closely follows airborne radar-derived mapping (Forster et al., in press). The average top surface depth of the PFA as detected by radar is 23 m. In April 2013, our team drilled through the PFA for the first time to gain an understanding of firn structure constraining the PFA, to estimate the water volume within the PFA, and to measure PFA temperatures and densities. At our drill site in Southeast Greenland (~100 km Northwest of Kulusuk), water fills or partially fills the available firn pore space from depths of ~12 to 37 m. The temperature within the PFA depths is constant at 0.1 × 0.1° C while the 12 m of seasonally dry firn above the PFA has a temperature profile dominated by surface temperature forcing. Near the bottom of the PFA water completely fills available pore space as the firn is compressed to ice entrapping water filled bubbles, as opposed to air filled bubbles, which then start to refreeze. A PFA maximum density is reached as the water filling the pore space, increasing density, begins refreezing back into ice at a lower density. We define this depth as the pore water refreeze depth and use this depth as the bottom of the PFA to calculate volume. It is certain, however that a small amount of water does exist below this depth, which we do not account for. The density profile obtained from the ACT11B firn core, the closest seasonally dry firn core, is compared to both gravitational densities and high resolution densities derived from a neutron density probe at the PFA site. The

  10. A regional-scale estimation of ice wedge ice volumes in the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Templeton, M.; Pollard, W. H.; Grand'Maison, C. B.

    2016-12-01

    Ice wedges are both prominent and environmentally vulnerable features in continuous permafrost environments. As the world's Arctic regions begin to warm, concern over the potential effects of ice wedge melt out has become an immediate issue, receiving much attention in the permafrost literature. In this study we estimate the volume of ice wedge ice for large areas in the Canadian High Arctic through the use of high resolution satellite imagery and the improved capabilities of Geographic Information Systems (GIS). The methodology used for this study is similar to that of one performed in Siberia and Alaska by Ulrich et al, in 2014. Utilizing Ulrich's technique, this study detected ice wedge polygons from satellite imagery using ArcGIS. The average width and depth of these ice wedges were obtained from a combination of field data and long-term field studies for the same location. The assumptions used in the analysis of ice wedge volume have been tested, including trough width being representative of ice wedge width, and ice wedge ice content (Pollard and French 1980). This study used specific field sites located near Eureka on Ellesmere Island (N80°01', W85°43') and at Expedition Fiord on Axel Heiberg Island (N79°23', W90°59'). The preliminary results indicate that the methodology used by Ulrich et al, 2014 is transferrable to the Canadian High Arctic, and that ice wedge volumes range between 3-10% of the upper part of permafrost. These findings are similar to previous studies and their importance is made all the more evident by the dynamic nature of ice wedges where it could be argued that they are a key driver of thermokarst terrain. The ubiquitous nature of ice wedges across arctic terrain highlights the importance and the need to improve our understanding of ice wedge dynamics, as subsidence from ice wedge melt-out could lead to large scale landscape change.

  11. Statistical analyses of nuclear waste level measurements to estimate retained gas volumes

    NASA Astrophysics Data System (ADS)

    Whitney, Paul D.; Chen, Guang

    1999-01-01

    The Hanford site is home to 177 large, underground nuclear waste storage tanks. Numerous safety and environmental concerns around these tanks and their contents. One such concern is the propensity for the waste in these tanks to generate and retain flammable gases. The surface level of the waste in these tanks is routinely monitored to assess whether the tanks are leaking. For some of the tanks, the waste surface level measurements synchronously fluctuated with atmospheric pressure changes. The current best explanation for these synchronous fluctuations is that the waste contains gas-phase material that changes volume in response to the atmospheric pressure changes. This paper describes: (1) The exploratory data analysis that led to the discovery of the phenomena; (2) A physical mode based on the ideal gas law that explains the phenomena. Additionally, the model allows one to obtain estimates of the retained gas volume in the tank waste; (3) A statistical procedure for detecting retained gas based on the physical model and tank surface level measurements; and (4) A Kalman filter model for analyzing the dynamics of retained gas. It's also shown how the filter can be used to detect abrupt changes in the system.

  12. Simulation of DNAPL migration in heterogeneous translucent porous media based on estimation of representative elementary volume

    NASA Astrophysics Data System (ADS)

    Wu, Ming; Wu, Jianfeng; Wu, Jichun

    2017-10-01

    When the dense nonaqueous phase liquid (DNAPL) comes into the subsurface environment, its migration behavior is crucially affected by the permeability and entry pressure of subsurface porous media. A prerequisite for accurately simulating DNAPL migration in aquifers is then the determination of the permeability, entry pressure and corresponding representative elementary volumes (REV) of porous media. However, the permeability, entry pressure and corresponding representative elementary volumes (REV) are hard to determine clearly. This study utilizes the light transmission micro-tomography (LTM) method to determine the permeability and entry pressure of two dimensional (2D) translucent porous media and integrates the LTM with a criterion of relative gradient error to quantify the corresponding REV of porous media. As a result, the DNAPL migration in porous media might be accurately simulated by discretizing the model at the REV dimension. To validate the quantification methods, an experiment of perchloroethylene (PCE) migration is conducted in a two-dimensional heterogeneous bench-scale aquifer cell. Based on the quantifications of permeability, entry pressure and REV scales of 2D porous media determined by the LTM and relative gradient error, different models with different sizes of discretization grid are used to simulate the PCE migration. It is shown that the model based on REV size agrees well with the experimental results over the entire migration period including calibration, verification and validation processes. This helps to better understand the microstructures of porous media and achieve accurately simulating DNAPL migration in aquifers based on the REV estimation.

  13. A Theoretical Mathematical Model to Estimate Blood Volume in Clinical Practice.

    PubMed

    D'Angelo, Matthew; Hodgen, R Kyle; Wofford, Kenneth; Vacchiano, Charles

    2015-10-01

    Perioperative intravenous (IV) fluid management is controversial. Fluid therapy is guided by inaccurate algorithms and changes in the patient's vital signs that are nonspecific for changes to the patient's blood volume (BV). Anesthetic agents, patient comorbidities, and surgical techniques interact and further confound clinical assessment of volume status. Through adaptation of existing acute normovolemic hemodilution algorithms, it may be possible to predict patient's BV by measuring hematocrit (HcT) before and after hemodilution. Our proposed mathematical model requires the following four data points to estimate a patient's total BV: ideal BV, baseline HcT, a known fluid bolus (FB), and a second HcT following the FB. To test our method, we obtained 10 ideal and 10 actual subject BV data measures from 9 unique subjects derived from a commercially used Food and Drug Administration-approved, semi-automated, BV analyzer. With these data, we calculated the theoretical BV change following a FB. Using the four required data points, we predicted BVs (BVp) and compared our predictions with the actual BV (BVa) measures provided by the data set. The BVp calculated using our model highly correlated with the BVa provided by the BV analyzer data set (df = 8, r = .99). Our calculations suggest that, with accurate HcT measurement, this method shows promise for the identification of abnormal BV states such as hyper- and hypovolemia and may prove to be a reliable method for titrating IV fluid.

  14. Brain volume estimation from post-mortem newborn and fetal MRI

    PubMed Central

    Orasanu, Eliza; Melbourne, Andrew; Cardoso, M. Jorge; Modat, Marc; Taylor, Andrew M.; Thayyil, Sudhin; Ourselin, Sebastien

    2014-01-01

    Objective Minimally invasive autopsy using post-mortem magnetic resonance imaging (MRI) is a valid alternative to conventional autopsy in fetuses and infants. Estimation of brain weight is an integral part of autopsy, but manual segmentation of organ volumes on MRI is labor intensive and prone to errors, therefore unsuitable for routine clinical practice. In this paper we aim to show that volumetric measurements of the post-mortem fetal and neonatal brain can be accurately estimated using semi-automatic techniques and a high correlation can be found with the weights measured from conventional autopsy results. Methods The brains of 17 newborn subjects, part of Magnetic Resonance Imaging Autopsy Study (MaRIAS), were segmented from post-mortem MR images into cerebrum, cerebellum and brainstem using a publicly available neonate brain atlas and semi-automatic segmentation algorithm. The results of the segmentation were averaged to create a new atlas, which was then used for the automated atlas-based segmentation of 17 MaRIAS fetus subjects. As validation, we manually segmented the MR images from 8 subjects of each cohort and compared them with the automatic ones. The semi-automatic estimation of cerebrum weight was compared with the results of the conventional autopsy. Results The Dice overlaps between the manual and automatic segmentations are 0.991 and 0.992 for cerebrum, 0.873 and 0.888 for cerebellum and 0.819 and 0.815 for brainstem, for newborns and fetuses, respectively. Excellent agreement was obtained between the estimated MR weights and autopsy gold standard ones: mean absolute difference of 5 g and 2% maximum error for the fetus cohort and mean absolute difference of 20 g and 11% maximum error for the newborn one. Conclusions The high correlation between the obtained segmentation and autopsy weights strengthens the idea of using post-mortem MRI as an alternative for conventional autopsy of the brain. PMID:25379457

  15. A mathematical formula to estimate in vivo thyroid volume from two-dimensional ultrasonography.

    PubMed

    Trimboli, Pierpaolo; Ruggieri, Massimo; Fumarola, Angela; D'Alò, Michele; Straniero, Andrea; Maiuolo, Amelia; Ulisse, Salvatore; D'Armiento, Massimino

    2008-08-01

    The determination of thyroid volume (TV) is required for the management of thyroid diseases. Since two-dimensional ultrasonography (2D-US) has become the accepted method for the assessment of TV (2D-US-TV), we verified whether it accurately assesses postsurgical measured TV (PS-TV). In 92 patients who underwent total thyroidectomy by conventional cervicotomy, 2D-US-TV obtained by the ellipsoid volume formula was compared to PS-TV, determined by the Archimedes' principle. Mean 2D-US-TV (23.9 +/- 14.8 mL) was significantly lower than mean PS-TV (33.4 +/- 20.1 mL). Underestimation was observed in 77% of cases, and it was related to gland multinodularity and/or nodular involvement of the isthmus, while 2D-US-TV matched the PS-TV in the remaining 21 cases (23%). A mathematical formula, to estimate PS-TV from US-TV, was derived using a linear model (Calculated-TV = [1.24 x 2D-US-TV]+ 3.66). Calculated-TV (mean value 33.4 +/- 18.3 mL) significantly (p < 0.01) increased from 21 (23%) to 31 (34%) of the cases that matched PS-TV. In addition, it significantly (p < 0.01) decreased from 77% to 27% the percentage of cases where PS-TV was underestimated as well as the range of the disagreement from 245% to 92%. This study shows that 2D-US does not provide an accurate estimation of TV and suggests that it can be improved by a mathematical model different from the ellipsoid model. If confirmed in prospective studies, this may contribute to a more appropriate management of thyroid diseases.

  16. [Physiopathology of left ventricular remodeling after myocardial infarction].

    PubMed

    Bassand, J P; Anguenot, T

    1991-12-01

    The geometry of both the infarcted and non-infarcted zone of the left ventricle changes after myocardial infarction. Two mechanisms are involved: expansion of the infarcted zone and secondary dilatation of the non-infarcted zone. The necrosed area undergoes an inflammatory reaction followed by fibrosis which end up as a sca within a period of a few days to a few weeks. During this period if fibrous scarring the infarcted, thinned myocardium undergoes progressive expansion which starts in the first hours of the myocardial infarction. The loss of left ventricular systolic function related to the infarct and volumic overload created by expansion of the infarct influence the secondary development of dilatation of the non-infarcted zones. This dilatation results in restoration of left ventricular stroke volume but at the price of increased wall stress, which itself induces compensatory wall hypertrophy. These phenomena are more pronounced when the initial infarction is extensive and if they are sustained, they result in definitive myocardial failure. Several factors influence remodeling: the size of the infarct, arterial patency, wall stress and the quality of the scarring process itself. Therapeutic interventions of each of these factors can influence the remodeling. Limitation of infarct size by thrombolytic therapy, arterial revascularisation, even when performed late, seem capable of limiting expansion of the necrosed zone. Pharmacodynamic intervention of left ventricular afterload also affects ventricular remodeling. Nitrate derivatives, vasodilator therapy in general and converting enzyme inhibitors have been shown to be effective.

  17. Estimation of brain perfusion using Va value as initial distribution volume in radionuclide angiography with technetium-99m HMPAO

    SciTech Connect

    Kawamoto, M.; Ikegami, T.

    1994-05-01

    Matsuda reported a non-invasive, simple method for the quantitative measurements of brain perfusion using radionuclide angiography with Tc-99m. HMPAO and showed graphical analysis of the ratio of brain activity to aortic arch activity gave two parameters, which are the slope of the fitted line (Ku:unidirectional influx constant) and its intercept with the yards (Vn:initial volume of distribution). Brain perfusion index (BPI),which is a connected Ku value, showed good correlation with cerebral blood flow determined with Xe-133 SPECT. The aim of our study is to elucidate the clinical significance of another parameter, Vn value, determined inpatients with cerebral vessel disease. Eighty-nine cases were studied and classified into three groups on the basis of clinical history and images of CT and/or MR: Group A, normal, 36 cases; Group B, infarction, 44 cases; Group C, subarachnoid hemorrhage, 9 cases. The average age of each group were not different statistically (63.3, 67.4 and 59.8, respectively). The average BPI values for group B and C were significantly lower than that of group A(7.7, 6. 8 and 9.5, respectively ). On the other hand, Vn for group C(0.23) was significantly lower than that for group A(0.45); however that for group B(0.49) was not. These findings indicate that cerebral blood flow in both infarction and subarachnoid hemorrhage decrease but their circumstances near vessels differ from the aspect of initial volume of tracer distribution. This might help to understand or diagnose cerebral vessel diseases.

  18. Estimating changes in volume-weighted mean body temperature using thermometry with an individualized correction factor.

    PubMed

    Jay, Ollie; DuCharme, Michel B; Webb, Paul; Reardon, Francis D; Kenny, Glen P

    2010-08-01

    This study investigated whether the estimation error of volume-weighted mean body temperature (DeltaT(b)) using changes in core and skin temperature can be accounted for using personal and environmental parameters. Whole body calorimetry was used to directly measure DeltaT(b) in an Experimental group (EG) of 36 participants (24 males, 12 females) and a Validation group (VG) of 20 (9 males, 11 females) throughout 90 min of cycle ergometry at 40 degrees C, 30% relative humidity (RH) (n = 9 EG, 5 VG); 30 degrees C, 30% RH (n = 9 EG, 5 VG); 30 degrees C, 60% RH (n = 9 EG, 5 VG); and 24 degrees C, 30% RH (n = 9 EG, 5 VG). The core of the two-compartment thermometry model was represented by rectal temperature and the shell by a 12-point mean skin temperature (DeltaT(sk)). The estimation error (X(0)) between DeltaT(b) from calorimetry and DeltaT(b) from thermometry using core/shell weightings of 0.66/0.34, 0.79/0.21, and 0.90/0.10 was calculated after 30, 60, and 90 min of exercise, respectively. The association between X(0) and the individual variation in metabolic heat production (M - W), body surface area (BSA), body fat percentage (%fat), and body surface area-to-mass ratio (BSA/BM) as well as differences in environmental conditions (Oxford index) in the EG data were assessed using stepwise linear regression. At all time points and with all core/shell weightings tested, M - W, BSA, and Oxford index independently correlated significantly with the residual variance in X(0), but %fat and BSA/BM did not. The subsequent regression models were used to predict the thermometric estimation error (X(0_pred)) for each individual in the VG. The value estimated for X(0_pred) was then added to the DeltaT(b) estimated using the two-compartment thermometry models yielding an adjusted estimation (DeltaT(b)_(adj)) for the individuals in the VG. When comparing DeltaT(b)_(adj) to the DeltaT(b) derived from calorimetry in the VG, the best performing model used a core/shell weighting of 0

  19. Estimating the global volume of deeply recycled continental crust at continental collision zones

    NASA Astrophysics Data System (ADS)

    Scholl, D. W.; Huene, R. V.

    2006-12-01

    CRUSTAL RECYCLING AT OCEAN MARGINS: Large volumes of rock and sediment are missing from the submerged forearcs of ocean margin subduction zones--OMSZs. This observation means that (1) oceanic sediment is transported beneath the margin to either crustally underplate the coastal region or reach mantle depths, and that (2) the crust of the forearc is vertically thinned and horizontally truncated and the removed material transported toward the mantle. Transport of rock and sediment debris occurs in the subduction channel that separates the upper and lower plates. At OMSZs the solid-volume flux of recycling crustal material is estimated to be globally ~2.5 km3/yr (i.e., 2.5 Armstrong units or AU). The corresponding rate of forearc truncation (migration of the trench axis toward a fix reference on the continent) is a sluggish 2-3 km/Myr (about 1/50th the orthogonal convergence rate). Nonetheless during the past 2.5 Gyr (i.e., since the beginning of the Proterozoic) a volume of continental material roughly equal to the existing volume (~7 billion cubic km) has been recycled to the mantle at OMSZs. The amount of crust that has been destroyed is so large that recycling must have been a major factor creating the mapped rock pattern and age-fabric of continental crust. RECYCLING AT CONTINENT/ARC COLLISIONS: The rate at which arc magmatism globally adds juvenile crust to OMSZs has been commonly globally estimated at ~1 AU. But new geophysical and dating information from the Aleutian and IBM arcs imply that the addition rate is at least ~5 AU (equivalent to ~125 km3/Myr/km of arc). If the Armstrong posit is correct that since the early Archean a balance has existed between additions and losses of crust, then a recycling sink for an additional 2-3 AU of continental material must exist. As the exposure of exhumed masses of high P/T blueschist bodies documents that subcrustal streaming of continental material occurs at OMSZs, so does the occurrence of exhumed masses of UHP

  20. Estimation of Values below the Limit of Detection of a Contemporary Sensitive Troponin I Assay Improves Diagnosis of Acute Myocardial Infarction.

    PubMed

    Boeckel, Jes-Niels; Palapies, Lars; Zeller, Tanja; Reis, Sophia M; von Jeinsen, Beatrice; Tzikas, Stergios; Bickel, Christoph; Baldus, Stephan; Blankenberg, Stefan; Münzel, Thomas; Zeiher, Andreas M; Lackner, Karl J; Keller, Till

    2015-09-01

    The limit of detection (LoD) is the minimal amount of a substance that can be consistently detected. In the diagnosis of acute myocardial infarction (AMI) many patients present with troponin concentrations below the LoD of contemporary sensitive cardiac troponin I (cs-cTnI) assays. These censored values below the LoD influence the diagnostic performance of these assays compared to highly sensitive cTnI (hs-cTnI) assays. Therefore we assessed the impact of a new approach for interpolation of the left-censored data of a cs-cTnI assay in the evaluation of patients with suspected AMI. Our posthoc analysis used a real world cohort of 1818 patients with suspected MI. Data on cs-cTnI was available in 1786 patients. As a comparator the hs-cTnI version of the assay was used. To reconstruct quantities below the LoD of the cs-cTnI assay, a gamma regression approach incorporating the GRACE (Global Registry of Acute Coronary Events) score variables was used. Censoring of cs-cTnI data below the LoD yielded weaker diagnostic information [area under the curve (AUC), 0.781; 95% CI, 0.731-0.831] regarding AMI compared to the hs-cTnI assay (AUC, 0.949; CI, 0.936-0.961). Use of our model to estimate cs-cTnI values below the LoD showed an AUC improvement to 0.921 (CI, 0.902-0.940). The cs-cTnI LoD concentration had a negative predictive value (NPV) of 0.950. An estimated concentration that was to be undercut by 25% of patients presenting with suspected AMI was associated with an improvement of the NPV to 0.979. Estimation of values below the LoD of a cs-cTnI assay with this new approach improves the diagnostic performance in evaluation of patients with suspected AMI. © 2015 American Association for Clinical Chemistry.

  1. Form-class volume tables for estimating board-foot content of northern conifers

    Treesearch

    C. Allen Bickford

    1951-01-01

    The timber cruiser counts volume tables among his most important working tools. He wants - if he can get them - tables that are simple, easy to use, and accurate. Before using a volume table in a new situation, the careful cruiser will check it by comparing table volumes with actual volumes.

  2. Best single-slice measurement site for estimating visceral adipose tissue volume after weight loss in obese, Japanese men.

    PubMed

    So, Rina; Matsuo, Tomoaki; Sasai, Hiroyuki; Eto, Miki; Tsujimoto, Takehiko; Saotome, Kousaku; Tanaka, Kiyoji

    2012-06-14

    Although the measurement site at L4-L5 for visceral adipose tissue (VAT) has been commonly accepted, some researchers suggest that additional upper sites (i.e., L1-L2 and L2-L3) are useful for estimating VAT volume. Therefore, determining the optimum measurement site remains challenging and has become important in determining VAT volume. We investigated the influence of a single-slice measurement site on the prediction of VAT volume and changes in VAT volume in obese Japanese men. Twenty-four men, aged 30-65 years with a mean BMI of 30 kg/m2, were included in a 12-week weight loss program. We obtained continuous T1-weighted abdominal magnetic resonance images from T9 to S1 with a 1.5-T system to measure the VAT area. These VAT areas were then summed to determine VAT volume before and after the program. Single-slice images at 3-11 cm above L4-L5 had significant and high correlations with VAT volume at baseline (r=0.94-0.97). The single-slice image with the highest correlation coefficient with respect to VAT volume was located at 5 cm above L4-L5 (r=0.97). The highest correlation coefficient between the individual changes in VAT area and changes in VAT volume was located at 6 cm above L4-L5 (r=0.90). Individual measurement sites have different abilities to estimate VAT volume and changes in VAT volume in obese Japanese men. Best zone located at 5-6 cm above L4-L5 may be a better predictor of VAT volume than the L4-L5 image in terms of both baseline and changes with weight loss.

  3. Estimation of Volume Deficit Characteristic of Cast Al-Si-Mg Alloy

    NASA Astrophysics Data System (ADS)

    Santhi, S.; Sakri, S. B.; Rao, D. Hanumantha; Sundarrajan, S.

    2013-04-01

    Volume deficit characteristic of US A356 cast aluminium alloy has been discussed in the present study. The reduction in specific volume leads to volume deficit in castings and it can be visualized as a casting defect. The information regarding the volume deficit and its distribution is essential in minimizing casting defects. The volume deficit can be classified as macro cavities, internal porosity, surface sinks and volumetric contraction. These defects are measured using mathematical formulae and the actual volume deficit of the given casting has been arrived by adding all the defects. Influence of bottom chill and casting shape on the volume deficit characteristics have been studied.

  4. Reduced infarct size in neuroglobin-null mice after experimental stroke in vivo

    PubMed Central

    2012-01-01

    Background Neuroglobin is considered to be a novel important pharmacological target in combating stroke and neurodegenerative disorders, although the mechanism by which this protection is accomplished remains an enigma. We hypothesized that if neuroglobin is directly involved in neuroprotection, then permanent cerebral ischemia would lead to larger infarct volumes in neuroglobin-null mice than in wild-type mice. Methods Using neuroglobin-null mice, we estimated the infarct volume 24 hours after permanent middle cerebral artery occlusion using Cavalieri’s Principle, and compared the infarct volume in neuroglobin-null and wild-type mice. Neuroglobin antibody staining was used to examine neuroglobin expression in the infarct area of wild-type mice. Results Infarct volumes 24 hours after permanent middle cerebral artery occlusion were significantly smaller in neuroglobin-null mice than in wild-types (p < 0.01). Neuroglobin immunostaining of the penumbra area revealed no visible up-regulation of neuroglobin protein in ischemic wild-type mice when compared to uninjured wild-type mice. In uninjured wild-type mice, neuroglobin protein was seen throughout cortical layer II and sparsely in layer V. In contrast, no neuroglobin-immunoreactive neurons were observed in the aforementioned layers of the ischemia injured cortical area, or in the surrounding penumbra of ischemic wild-type mice. This suggests no selective sparing of neuroglobin expressing neurons in ischemia. Conclusions Neuroglobin-deficiency resulted in reduced tissue infarction, suggesting that, at least at endogenous expression levels, neuroglobin in itself is non-protective against ischemic injury. PMID:22901501

  5. Neural mechanisms and delayed gastric emptying of liquid induced through acute myocardial infarction in rats.

    PubMed

    Nunez, Wilson Ranu Ramirez; Ozaki, Michiko Regina; Vinagre, Adriana Mendes; Collares, Edgard Ferro; Almeida, Eros Antonio de

    2015-02-01

    In pathological situations, such as acute myocardial infarction, disorders of motility of the proximal gut can trigger symptoms like nausea and vomiting. Acute myocardial infarction delays gastric emptying (GE) of liquid in rats. Investigate the involvement of the vagus nerve, α 1-adrenoceptors, central nervous system GABAB receptors and also participation of paraventricular nucleus (PVN) of the hypothalamus in GE and gastric compliance (GC) in infarcted rats. Wistar rats, N = 8-15 in each group, were divided as INF group and sham (SH) group and subdivided. The infarction was performed through ligation of the left anterior descending coronary artery. GC was estimated with pressure-volume curves. Vagotomy was performed by sectioning the dorsal and ventral branches. To verify the action of GABAB receptors, baclofen was injected via icv (intracerebroventricular). Intravenous prazosin was used to produce chemical sympathectomy. The lesion in the PVN of the hypothalamus was performed using a 1 mA/10 s electrical current and GE was determined by measuring the percentage of gastric retention (% GR) of a saline meal. No significant differences were observed regarding GC between groups; vagotomy significantly reduced % GR in INF group; icv treatment with baclofen significantly reduced %GR. GABAB receptors were not conclusively involved in delaying GE; intravenous treatment with prazosin significantly reduced GR% in INF group. PVN lesion abolished the effect of myocardial infarction on GE. Gastric emptying of liquids induced through acute myocardial infarction in rats showed the involvement of the vagus nerve, alpha1- adrenergic receptors and PVN.

  6. Volume estimation of small phantoms and rat kidneys using three-dimensional ultrasonography and a position sensor.

    PubMed

    Strømmen, Kenneth; Stormark, Tor André; Iversen, Bjarne M; Matre, Knut

    2004-09-01

    To evaluate the accuracy of small volume estimation, both in vivo and in vitro, measurements with a three-dimensional (3D) ultrasound (US) system were carried out. A position sensor was used and the transmitting frequency was 10 MHz. Balloons with known volumes were scanned while rat kidneys were scanned in vivo and in vitro. The Archimedes' principle was used to estimate the true volume. For balloons, the 3D US system gave very good agreement with true volumes in the volume range 0.1 to 10.0 mL (r = 0.999, n = 45, mean difference +/- 2SD = 0.245 +/- 0.370 mL). For rat kidneys in vivo (volume range 0.6 to 2.7 mL) the method was less accurate (r = 0.800, n = 10, mean difference +/- 2SD = -0.288 +/- 0.676 mL). For rat kidneys in vitro (volume range 0.3 to 2.7 mL) the results showed good agreement (r = 0.981, n = 23, mean difference +/- 2SD = 0.039 +/- 0.254 mL). For balloons, kidneys in vivo and in vitro, the mean percentage error was 9.3 +/- 4.8%, -17.1 +/- 17.4%, and 4.6 +/- 11.5%, respectively. This method can estimate the volume of small phantoms and rat kidneys and opens new possibilities for volume measurements of small objects and the study of organ function in small animals. (E-mail ).

  7. Regional left ventricular myocardial contractility and stress in a finite element model of posterobasal myocardial infarction.

    PubMed

    Wenk, Jonathan F; Sun, Kay; Zhang, Zhihong; Soleimani, Mehrdad; Ge, Liang; Saloner, David; Wallace, Arthur W; Ratcliffe, Mark B; Guccione, Julius M

    2011-04-01

    Recently, a noninvasive method for determining regional myocardial contractility, using an animal-specific finite element (FE) model-based optimization, was developed to study a sheep with anteroapical infarction (Sun et al., 2009, "A Computationally Efficient Formal Optimization of Regional Myocardial Contractility in a Sheep With Left Ventricular Aneurysm," ASME J. Biomech. Eng., 131(11), p. 111001). Using the methodology developed in the previous study (Sun et al., 2009, "A Computationally Efficient Formal Optimization of Regional Myocardial Contractility in a Sheep With Left Ventricular Aneurysm," ASME J. Biomech. Eng., 131(11), p. 111001), which incorporates tagged magnetic resonance images, three-dimensional myocardial strains, left ventricular (LV) volumes, and LV cardiac catheterization pressures, the regional myocardial contractility and stress distribution of a sheep with posterobasal infarction were investigated. Active material parameters in the noninfarcted border zone (BZ) myocardium adjacent to the infarct (T(max_B)), in the myocardium remote from the infarct (T(max_R)), and in the infarct (T(max_I)) were estimated by minimizing the errors between FE model-predicted and experimentally measured systolic strains and LV volumes using the previously developed optimization scheme. The optimized T(max_B) was found to be significantly depressed relative to T(max_R), while T(max_I) was found to be zero. The myofiber stress in the BZ was found to be elevated, relative to the remote region. This could cause further damage to the contracting myocytes, leading to heart failure.

  8. Main Trend Extraction Based on Irregular Sampling Estimation and Its Application in Storage Volume of Internet Data Center

    PubMed Central

    Dou, Chao

    2016-01-01

    The storage volume of internet data center is one of the classical time series. It is very valuable to predict the storage volume of a data center for the business value. However, the storage volume series from a data center is always “dirty,” which contains the noise, missing data, and outliers, so it is necessary to extract the main trend of storage volume series for the future prediction processing. In this paper, we propose an irregular sampling estimation method to extract the main trend of the time series, in which the Kalman filter is used to remove the “dirty” data; then the cubic spline interpolation and average method are used to reconstruct the main trend. The developed method is applied in the storage volume series of internet data center. The experiment results show that the developed method can estimate the main trend of storage volume series accurately and make great contribution to predict the future volume value. 
 PMID:28090205

  9. Estimating Plume Volume for Geologic Storage of CO2 in Saline Aquifers

    SciTech Connect

    Doughty, Christine

    2008-07-11

    Typically, when a new subsurface flow and transport problem is first being considered, very simple models with a minimal number of parameters are used to get a rough idea of how the system will evolve. For a hydrogeologist considering the spreading of a contaminant plume in an aquifer, the aquifer thickness, porosity, and permeability might be enough to get started. If the plume is buoyant, aquifer dip comes into play. If regional groundwater flow is significant or there are nearby wells pumping, these features need to be included. Generally, the required parameters tend to be known from pre-existing studies, are parameters that people working in the field are familiar with, and represent features that are easy to explain to potential funding agencies, regulators, stakeholders, and the public. The situation for geologic storage of carbon dioxide (CO{sub 2}) in saline aquifers is quite different. It is certainly desirable to do preliminary modeling in advance of any field work since geologic storage of CO{sub 2} is a novel concept that few people have much experience with or intuition about. But the parameters that control CO{sub 2} plume behavior are a little more daunting to assemble and explain than those for a groundwater flow problem. Even the most basic question of how much volume a given mass of injected CO{sub 2} will occupy in the subsurface is non-trivial. However, with a number of simplifying assumptions, some preliminary estimates can be made, as described below. To make efficient use of the subsurface storage volume available, CO{sub 2} density should be large, which means choosing a storage formation at depths below about 800 m, where pressure and temperature conditions are above the critical point of CO{sub 2} (P = 73.8 bars, T = 31 C). Then CO{sub 2} will exist primarily as a free-phase supercritical fluid, while some CO{sub 2} will dissolve into the aqueous phase.

  10. First tomographic estimate of volume distribution of HF-pump enhanced airglow emission

    NASA Astrophysics Data System (ADS)

    Gustavsson, B.; Sergienko, T.; Rietveld, M. T.; Honary, F.; Steen, Å.; Brändström, B. U. E.; Leyser, T. B.; Aruliah, A. L.; Aso, T.; Ejiri, M.; Marple, S.

    2001-12-01

    This report presents the first estimates of the three-dimensional volume emission rate of enhanced O(1D) 6300 Å airglow caused by HF radio wave pumping in the ionosphere. Images of the excitation show how the initially speckled spatial structure of excitation changes to a simpler shape with a smaller region that contains most of the excitation. A region of enhanced airglow was imaged by three stations in the Auroral Large Imaging System (ALIS) in northern Scandinavia. These images allowed for a tomography-like inversion of the volume emission of the airglow. The altitude of maximum emission was found to be around 235+/-5km with typical horizontal and vertical scale sizes of 20 km. The shape of the O(1D) excitation rate varied from flatish to elongated along the magnetic field. The altitude of maximum emission is found to be approximately 10 km below the altitude of the enhanced ion line and 15 km above the altitude of maximum electron temperature. Comparisons of the measured altitude and temporal variations of the 6300 Å emission with modelled emission caused by O(1D) excitation from the high energy tail of a Maxwellian electron distribution show significant deviations. The 6300 Å emission from excitation of the high energy tail is about a factor of 4 too large compared with what is observed. This shows that the source of O(1D) excitation is electrons from a ``sub-thermal'' distribution function, i.e. the electron distribution is Maxwellian at low energies and at energies above 1.96 eV there is a depletion.

  11. A New Approach for Deep Gray Matter Analysis Using Partial-Volume Estimation.

    PubMed

    Bonnier, Guillaume; Kober, Tobias; Schluep, Myriam; Du Pasquier, Renaud; Krueger, Gunnar; Meuli, Reto; Granziera, Cristina; Roche, Alexis

    2016-01-01

    The existence of partial volume effects in brain MR images makes it challenging to understand physio-pathological alterations underlying signal changes due to pathology across groups of healthy subjects and patients. In this study, we implement a new approach to disentangle gray and white matter alterations in the thalamus and the basal ganglia. The proposed method was applied to a cohort of early multiple sclerosis (MS) patients and healthy subjects to evaluate tissue-specific alterations related to diffuse inflammatory or neurodegenerative processes. Forty-three relapsing-remitting MS patients and nineteen healthy controls underwent 3T MRI including: (i) fluid-attenuated inversion recovery, double inversion recovery, magnetization-prepared gradient echo for lesion count, and (ii) T1 relaxometry. We applied a partial volume estimation algorithm to T1 relaxometry maps to gray and white matter local concentrations as well as T1 values characteristic of gray and white matter in the thalamus and the basal ganglia. Statistical tests were performed to compare groups in terms of both global T1 values, tissue characteristic T1 values, and tissue concentrations. Significant increases in global T1 values were observed in the thalamus (p = 0.038) and the putamen (p = 0.026) in RRMS patients compared to HC. In the Thalamus, the T1 increase was associated with a significant increase in gray matter characteristic T1 (p = 0.0016) with no significant effect in white matter. The presented methodology provides additional information to standard MR signal averaging approaches that holds promise to identify the presence and nature of diffuse pathology in neuro-inflammatory and neurodegenerative diseases.

  12. Estimate Landslide Volume with Genetic Algorithms and Image Similarity Method from Single Satellite Image

    NASA Astrophysics Data System (ADS)

    Yu, Ting-To

    2013-04-01

    It is important to acquire the volume of landslide in short period of time. For hazard mitigation and also emergency response purpose, the traditional method takes much longer time than expected. Due to the weather limit, traffic accessibility and many regulations of law, it take months to handle these process before the actual carry out of filed work. Remote sensing imagery can get the data as long as the visibility allowed, which happened only few day after the event. While traditional photometry requires a stereo pairs images to produce the post event DEM for calculating the change of volume. Usually have to wait weeks or even months for gathering such data, LiDAR or ground GPS measurement might take even longer period of time with much higher cost. In this study we use one post event satellite image and pre-event DTM to compare the similarity between these by alter the DTM with genetic algorithms. The outcome of smartest guess from GAs shall remove or add exact values of height at each location, which been converted into shadow relief viewgraph to compare with satellite image. Once the similarity threshold been make then the guessing work stop. It takes only few hours to finish the entire task, the computed accuracy is around 70% by comparing to the high resolution LiDAR survey at a landslide, southern Taiwan. With extra GCPs, the estimate accuracy can improve to 85% and also within few hours after the receiving of satellite image. Data of this demonstration case is a 5 m DTM at 2005, 2M resolution FormoSat optical image at 2009 and 5M LiDAR at 2010. The GAs and image similarity code is developed on Matlab at windows PC.

  13. Methods for estimating forest stem volumes by tree species using digital surface model and CIR images taken from light UAS

    NASA Astrophysics Data System (ADS)

    Salo, Heikki; Tirronen, Ville; Pölönen, Ilkka; Tuominen, Sakari; Balazs, Andras; Heikkilä, Jan; Saari, Heikki

    2012-06-01

    In this paper we consider methods for estimating forest tree stem volumes by species using images taken from light unmanned aircraft systems (UAS). Instead of using LiDAR and additional multiband imagery a color infrared camera mounted to a light UAS is used to acquire both imagery and the DSM of target area. The goal of this study is to accurately estimate tree stem volumes in three classes. The status of the ongoing work is described and an initial method for delineating and classifying treetops is presented.

  14. Estimation of the outer-sphere contribution to the activation volume for electron exchange reactions using the mean spherical approximation

    NASA Astrophysics Data System (ADS)

    Takagi, Hideo D.; Swaddle, Thomas W.

    1996-01-01

    The outer-sphere contribution to the volume of activation of homogeneous electron exchange reactions is estimated for selected solvents on the basis of the mean spherical approximation (MSA), and the calculated values are compared with those estimated by the Strank-Hush-Marcus (SHM) theory and with activation volumes obtained experimentally for the electron exchange reaction between tris(hexafluoroacetylacetonato)ruthenium(III) and -(II) in acetone, acetonitrile, methanol and chloroform. The MSA treatment, which recognizes the molecular nature of the solvent, does not improve significantly upon the continuous-dielectric SHM theory, which represents the experimental data adequately for the more polar solvents.

  15. Estimates of the Volume of Snowpack Sublimation in Arizona's Salt River Watershed

    NASA Astrophysics Data System (ADS)

    Svoma, B. M.

    2012-12-01

    The liquid equivalent volumes of snowpack sublimation, melt, and snowfall over the Salt River watershed, a major source of water for the Phoenix metropolitan area, will be estimated using the National Operational Hydrologic Remote Sensing Center's Snow Data Assimilation System (SNODAS) for the nine water years on record (i.e., 2004-2012). SNODAS integrates data from satellites, aircraft, and ground stations with downscaled output from numerical weather prediction models and an energy/mass balance snowpack model. The SNODAS dataset contains daily values of sublimation, snow water equivalent, snowfall, and melt, among other variables, at high (< 1 km2) resolution providing the opportunity to accurately estimate the volumes of snowpack balance variables for regions with complex topography. Snowpack ablation consists of sublimation and melting. Snow particles at sub-freezing temperatures will sublimate rather than melt if surrounded by air that is below the equilibrium water vapor pressure with respect to ice. When sublimation occurs, there is a direct loss of water from the given drainage basin when the vapor is carried away by the prevailing atmospheric flow. Preliminary analyses of water years 2005 (wet El Niño), 2007 (dry El Niño), 2008 (wet La Niña), and 2012 (dry La Niña) suggest that there is a substantial amount of sublimation over the Salt River watershed. From October 1 to April 30, approximately 16 percent of snowfall sublimated during the four years, ranging from approximately 98 million cubic meters (79,884 acre-feet) in water year 2005 to approximately 208 million cubic meters (168,726 acre-feet) in water year 2012. Sublimation is the most prevalent at the highest elevations of the watershed with more than 30 percent of snowfall sublimating at elevations above 2,744 meters above sea level. Of the four years analyzed, the sublimation to snowfall ratio was the highest for the two water years with anomalously high precipitation (i.e, 2005 and 2008). This

  16. Endocranial volume of Australopithecus africanus: new CT-based estimates and the effects of missing data and small sample size.

    PubMed

    Neubauer, Simon; Gunz, Philipp; Weber, Gerhard W; Hublin, Jean-Jacques

    2012-04-01

    Estimation of endocranial volume in Australopithecus africanus is important in interpreting early hominin brain evolution. However, the number of individuals available for investigation is limited and most of these fossils are, to some degree, incomplete and/or distorted. Uncertainties of the required reconstruction ('missing data uncertainty') and the small sample size ('small sample uncertainty') both potentially bias estimates of the average and within-group variation of endocranial volume in A. africanus. We used CT scans, electronic preparation (segmentation), mirror-imaging and semilandmark-based geometric morphometrics to generate and reconstruct complete endocasts for Sts 5, Sts 60, Sts 71, StW 505, MLD 37/38, and Taung, and measured their endocranial volumes (EV). To get a sense of the reliability of these new EV estimates, we then used simulations based on samples of chimpanzees and humans to: (a) test the accuracy of our approach, (b) assess missing data uncertainty, and (c) appraise small sample uncertainty. Incorporating missing data uncertainty of the five adult individuals, A. africanus was found to have an average adult endocranial volume of 454-461 ml with a standard deviation of 66-75 ml. EV estimates for the juvenile Taung individual range from 402 to 407 ml. Our simulations show that missing data uncertainty is small given the missing portions of the investigated fossils, but that small sample sizes are problematic for estimating species average EV. It is important to take these uncertainties into account when different fossil groups are being compared.

  17. Predictive Value of Estimated Tumor Volume Measured by Ultrasonography for Occult Central Lymph Node Metastasis in Papillary Thyroid Carcinoma.

    PubMed

    Park, Ki Nam; Kang, Kyung Yoon; Hong, Hyun Sook; Jeong, Han-Shin; Lee, Seung Won

    2015-11-01

    The clinical and prognostic value of tumor volume in various solid tumors has been investigated. However, there have been few studies on the clinical impact of tumor volume in papillary thyroid carcinoma (PTC). This study was performed to investigate the predictive value of estimated tumor volume measured by ultrasonography for occult central neck metastasis (OCNM) of PTC. A total of 264 patients with clinically node-negative PTC on ultrasonography and computed tomography who underwent total thyroidectomy in conjunction with at least ipsilateral prophylactic central neck dissection were enrolled in this study. Tumor volume was derived with the formula used to calculate ellipsoids from two orthogonal scans during 2-D ultrasonography at initial aspiration biopsy. We retrospectively evaluated demographic characteristics, pre-operative ultrasonographic features (tumor size, volume and multifocality) and pathologic results. The OCNM rate was 35.6%; estimated tumor volume was used to predict OCNM (p = 0.035). At 0.385 mL, sensitivity and specificity were 51.1% and 66.5%, and the area under the curve for OCNM detection was 0.610. In multivariate analysis, tumor volume, but not size, was an independent predictive factor for OCNM (odds ratio = 1.83, p = 0.029). The other factors were extrathyroidal extension (odds ratio = 2.39, p = 0.004) and male gender (odds ratio = 3.90, p < 0.001). The estimated tumor volume of PTC measured by ultrasonography could be a pre-operative predictor of OCNM. Copyright © 2015. Published by Elsevier Inc.

  18. Employing an Incentive Spirometer to Calibrate Tidal Volumes Estimated from a Smartphone Camera

    PubMed Central

    Reyes, Bersain A.; Reljin, Natasa; Kong, Youngsun; Nam, Yunyoung; Ha, Sangho; Chon, Ki H.

    2016-01-01

    A smartphone-based tidal volume (VT) estimator was recently introduced by our research group, where an Android application provides a chest movement signal whose peak-to-peak amplitude is highly correlated with reference VT measured by a spirometer. We found a Normalized Root Mean Squared Error (NRMSE) of 14.998% ± 5.171% (mean ± SD) when the smartphone measures were calibrated using spirometer data. However, the availability of a spirometer device for calibration is not realistic outside clinical or research environments. In order to be used by the general population on a daily basis, a simple calibration procedure not relying on specialized devices is required. In this study, we propose taking advantage of the linear correlation between smartphone measurements and VT to obtain a calibration model using information computed while the subject breathes through a commercially-available incentive spirometer (IS). Experiments were performed on twelve (N = 12) healthy subjects. In addition to corroborating findings from our previous study using a spirometer for calibration, we found that the calibration procedure using an IS resulted in a fixed bias of −0.051 L and a RMSE of 0.189 ± 0.074 L corresponding to 18.559% ± 6.579% when normalized. Although it has a small underestimation and slightly increased error, the proposed calibration procedure using an IS has the advantages of being simple, fast, and affordable. This study supports the feasibility of developing a portable smartphone-based breathing status monitor that provides information about breathing depth, in addition to the more commonly estimated respiratory rate, on a daily basis. PMID:26999152

  19. Estimation of central aortic pressure waveform features derived from the brachial cuff volume displacement waveform.

    PubMed

    Butlin, Mark; Qasem, Ahmad; Avolio, Alberto P

    2012-01-01

    There is increasing interest in non-invasive estimation of central aortic waveform parameters in the clinical setting. However, controversy has arisen around radial tonometric based systems due to the requirement of a trained operator or lack of ease of use, especially in the clinical environment. A recently developed device utilizes a novel algorithm for brachial cuff based assessment of aortic pressure values and waveform (SphygmoCor XCEL, AtCor Medical). The cuff was inflated to 10 mmHg below an individual's diastolic blood pressure and the brachial volume displacement waveform recorded. The aortic waveform was derived using proprietary digital signal processing and transfer function applied to the recorded waveform. The aortic waveform was also estimated using a validated technique (radial tonometry based assessment, SphygmoCor, AtCor Medical). Measurements were taken in triplicate with each device in 30 people (17 female) aged 22 to 79 years of age. An average for each device for each individual was calculated, and the results from the two devices were compared using regression and Bland-Altman analysis. A high correlation was found between the devices for measures of aortic systolic (R(2)=0.99) and diastolic (R(2)=0.98) pressure. Augmentation index and subendocardial viability ratio both had a between device R(2) value of 0.82. The difference between devices for measured aortic systolic pressure was 0.5±1.8 mmHg, and for augmentation index, 1.8±7.0%. The brachial cuff based approach, with an individualized sub-diastolic cuff pressure, provides an operator independent method of assessing not only systolic pressure, but also aortic waveform features, comparable to existing validated tonometric-based methods.

  20. Pilot Study: Estimation of Stroke Volume and Cardiac Output from Pulse Wave Velocity.

    PubMed

    Obata, Yurie; Mizogami, Maki; Nyhan, Daniel; Berkowitz, Dan E; Steppan, Jochen; Barodka, Viachaslau

    2017-01-01

    Transesophageal echocardiography (TEE) is increasingly replacing thermodilution pulmonary artery catheters to assess hemodynamics in patients at high risk for cardiovascular morbidity. However, one of the drawbacks of TEE compared to pulmonary artery catheters is the inability to measure real time stroke volume (SV) and cardiac output (CO) continuously. The aim of the present proof of concept study was to validate a novel method of SV estimation, based on pulse wave velocity (PWV) in patients undergoing cardiac surgery. This is a retrospective observational study. We measured pulse transit time by superimposing the radial arterial waveform onto the continuous wave Doppler waveform of the left ventricular outflow tract, and calculated SV (SVPWV) using the transformed Bramwell-Hill equation. The SV measured by TEE (SVTEE) was used as a reference. A total of 190 paired SV were measured from 28 patients. A strong correlation was observed between SVPWV and SVTEE with the coefficient of determination (R2) of 0.71. A mean difference between the two (bias) was 3.70 ml with the limits of agreement ranging from -20.33 to 27.73 ml and a percentage error of 27.4% based on a Bland-Altman analysis. The concordance rate of two methods was 85.0% based on a four-quadrant plot. The angular concordance rate was 85.9% with radial limits of agreement (the radial sector that contained 95% of the data points) of ± 41.5 degrees based on a polar plot. PWV based SV estimation yields reasonable agreement with SV measured by TEE. Further studies are required to assess its utility in different clinical situations.

  1. Pilot Study: Estimation of Stroke Volume and Cardiac Output from Pulse Wave Velocity

    PubMed Central

    Nyhan, Daniel; Berkowitz, Dan E.; Steppan, Jochen; Barodka, Viachaslau

    2017-01-01

    Background Transesophageal echocardiography (TEE) is increasingly replacing thermodilution pulmonary artery catheters to assess hemodynamics in patients at high risk for cardiovascular morbidity. However, one of the drawbacks of TEE compared to pulmonary artery catheters is the inability to measure real time stroke volume (SV) and cardiac output (CO) continuously. The aim of the present proof of concept study was to validate a novel method of SV estimation, based on pulse wave velocity (PWV) in patients undergoing cardiac surgery. Methods This is a retrospective observational study. We measured pulse transit time by superimposing the radial arterial waveform onto the continuous wave Doppler waveform of the left ventricular outflow tract, and calculated SV (SVPWV) using the transformed Bramwell-Hill equation. The SV measured by TEE (SVTEE) was used as a reference. Results A total of 190 paired SV were measured from 28 patients. A strong correlation was observed between SVPWV and SVTEE with the coefficient of determination (R2) of 0.71. A mean difference between the two (bias) was 3.70 ml with the limits of agreement ranging from -20.33 to 27.73 ml and a percentage error of 27.4% based on a Bland-Altman analysis. The concordance rate of two methods was 85.0% based on a four-quadrant plot. The angular concordance rate was 85.9% with radial limits of agreement (the radial sector that contained 95% of the data points) of ± 41.5 degrees based on a polar plot. Conclusions PWV based SV estimation yields reasonable agreement with SV measured by TEE. Further studies are required to assess its utility in different clinical situations. PMID:28060961

  2. Employing an Incentive Spirometer to Calibrate Tidal Volumes Estimated from a Smartphone Camera.

    PubMed

    Reyes, Bersain A; Reljin, Natasa; Kong, Youngsun; Nam, Yunyoung; Ha, Sangho; Chon, Ki H

    2016-03-18

    A smartphone-based tidal volume (V(T)) estimator was recently introduced by our research group, where an Android application provides a chest movement signal whose peak-to-peak amplitude is highly correlated with reference V(T) measured by a spirometer. We found a Normalized Root Mean Squared Error (NRMSE) of 14.998% ± 5.171% (mean ± SD) when the smartphone measures were calibrated using spirometer data. However, the availability of a spirometer device for calibration is not realistic outside clinical or research environments. In order to be used by the general population on a daily basis, a simple calibration procedure not relying on specialized devices is required. In this study, we propose taking advantage of the linear correlation between smartphone measurements and V(T) to obtain a calibration model using information computed while the subject breathes through a commercially-available incentive spirometer (IS). Experiments were performed on twelve (N = 12) healthy subjects. In addition to corroborating findings from our previous study using a spirometer for calibration, we found that the calibration procedure using an IS resulted in a fixed bias of -0.051 L and a RMSE of 0.189 ± 0.074 L corresponding to 18.559% ± 6.579% when normalized. Although it has a small underestimation and slightly increased error, the proposed calibration procedure using an IS has the advantages of being simple, fast, and affordable. This study supports the feasibility of developing a portable smartphone-based breathing status monitor that provides information about breathing depth, in addition to the more commonly estimated respiratory rate, on a daily basis.

  3. Novel Approach to Estimate Kidney and Cyst Volumes using Mid-Slice Magnetic Resonance Images in Polycystic Kidney Disease

    PubMed Central

    Bae, Kyongtae T; Tao, Cheng; Wang, Jinhong; Kaya, Diana; Wu, Zhiyuan; Bae, Junu T; Chapman, Arlene B; Torres, Vicente E; Grantham, Jared J; Mrug, Michal; Bennett, William M; Flessner, Michael F; Landsittel, Doug P

    2013-01-01

    Objective To evaluate whether kidney and cyst volumes can be accurately estimated based on limited area measurements from MR images of patients with autosomal dominant polycystic kidney disease (ADPKD). Materials and Methods MR coronal images of 178 ADPKD participants from the Consortium for Radiologic Imaging Studies of ADPKD (CRISP) were analyzed. For each MR image slice, we measured kidney and renal cyst areas using stereology and region-based thresholding methods, respectively. The kidney and cyst ‘observed’ volumes were calculated by summing up the area measurements of all the slices covering the kidney. To estimate the volume, we selected a coronal mid-slice in each kidney and multiplied its area by the total number of slices (‘PANK2’ for kidney and ‘PANC2’ for cyst). We then compared the kidney and cyst volumes predicted from PANK2 and PANC2, respectively, to the corresponding observed volumes, using a linear regression analysis. Results The kidney volume predicted from PANK2 correlated extremely well with the observed kidney volume: R2=0.994 for right and 0.991 for left kidney. The linear regression coefficient multiplier to PANK2 that best fit the kidney volume was 0.637 (95%CI: 0.629–0.644) for right and 0.624 (95%CI: 0.616–0.633) for left kidney. The correlation between the cyst volume predicted from PANC2 and the observed cyst volume was also very high: R2=0.984 for right and 0.967 for left kidney. The least squares linear regression coefficient for PANC2 was 0.637 (95%CI: 0.624–0.649) for right and 0.608 (95%CI: 0.591–0.625) for left kidney. Conclusion Kidney and cyst volumes can be closely approximated by multiplying the product of the mid-slice area measurement and the total number of slices in the coronal MR images of ADPKD kidneys by 0.61–0.64. This information will help save processing time needed to estimate total kidney and cyst volumes of ADPKD kidneys. PMID:24107679

  4. Predicting traffic volumes and estimating the effects of shocks in massive transportation systems

    PubMed Central

    Silva, Ricardo; Kang, Soong Moon; Airoldi, Edoardo M.

    2015-01-01

    Public transportation systems are an essential component of major cities. The widespread use of smart cards for automated fare collection in these systems offers a unique opportunity to understand passenger behavior at a massive scale. In this study, we use network-wide data obtained from smart cards in the London transport system to predict future traffic volumes, and to estimate the effects of disruptions due to unplanned closures of stations or lines. Disruptions, or shocks, force passengers to make different decisions concerning which stations to enter or exit. We describe how these changes in passenger behavior lead to possible overcrowding and model how stations will be affected by given disruptions. This information can then be used to mitigate the effects of these shocks because transport authorities may prepare in advance alternative solutions such as additional buses near the most affected stations. We describe statistical methods that leverage the large amount of smart-card data collected under the natural state of the system, where no shocks take place, as variables that are indicative of behavior under disruptions. We find that features extracted from the natural regime data can be successfully exploited to describe different disruption regimes, and that our framework can be used as a general tool for any similar complex transportation system. PMID:25902504

  5. Estimation of thickness of concentration boundary layers by osmotic volume flux determination.

    PubMed

    Jasik-Ślęzak, Jolanta S; Olszówka, Kornelia M; Slęzak, Andrzej

    2011-06-01

    The estimation method of the concentration boundary layers thicknesses (δ) in a single-membrane system containing non-electrolytic binary or ternary solutions was devised using the Kedem-Katchalsky formalism. A square equation used in this method contains membrane transport (L(p), σ, ω) and solution (D, C) parameters as well as a volume osmotic flux (J(v)). These values can be determined in a series of independent experiments. Calculated values δ are nonlinearly dependent on the concentrations of investigated solutions and the membrane system configuration. These nonlinearities are the effect of a competition between spontaneously occurring diffusion and natural convection. The mathematical model based on Kedem-Katchalsky equations and a concentration Rayleigh number (R(C)) was presented. On the basis of this model we introduce the dimensionless parameter, called by us a Katchalsky number (Ka), modifies R(C) of membrane transport. The critical value of this number well describes a moment of transition from the state of diffusion into convective diffusion membrane transport.

  6. Solid Waste Operations Complex W-113, Detail Design Report (Title II). Volume 4: Project cost estimate

    SciTech Connect

    1995-09-01

    The Solid Waste Retrieval Facility--Phase 1 (Project W113) will provide the infrastructure and the facility required to retrieve from Trench 04, Burial ground 4C, contact handled (CH) drums and boxes at a rate that supports all retrieved TRU waste batching, treatment, storage, and disposal plans. This includes (1) operations related equipment and facilities, viz., a weather enclosure for the trench, retrieval equipment, weighing, venting, obtaining gas samples, overpacking, NDE, NDA, shipment of waste and (2) operations support related facilities, viz., a general office building, a retrieval staff change facility, and infrastructure upgrades such as supply and routing of water, sewer, electrical power, fire protection, roads, and telecommunication. Title I design for the operations related equipment and facilities was performed by Raytheon/BNFL, and that for the operations support related facilities including infrastructure upgrade was performed by KEH. These two scopes were combined into an integrated W113 Title II scope that was performed by Raytheon/BNFL. This volume represents the total estimated costs for the W113 facility. Operating Contractor Management costs have been incorporated as received from WHC. The W113 Facility TEC is $19.7 million. This includes an overall project contingency of 14.4% and escalation of 17.4%. A January 2001 construction contract procurement start date is assumed.

  7. Predicting traffic volumes and estimating the effects of shocks in massive transportation systems.

    PubMed

    Silva, Ricardo; Kang, Soong Moon; Airoldi, Edoardo M

    2015-05-05

    Public transportation systems are an essential component of major cities. The widespread use of smart cards for automated fare collection in these systems offers a unique opportunity to understand passenger behavior at a massive scale. In this study, we use network-wide data obtained from smart cards in the London transport system to predict future traffic volumes, and to estimate the effects of disruptions due to unplanned closures of stations or lines. Disruptions, or shocks, force passengers to make different decisions concerning which stations to enter or exit. We describe how these changes in passenger behavior lead to possible overcrowding and model how stations will be affected by given disruptions. This information can then be used to mitigate the effects of these shocks because transport authorities may prepare in advance alternative solutions such as additional buses near the most affected stations. We describe statistical methods that leverage the large amount of smart-card data collected under the natural state of the system, where no shocks take place, as variables that are indicative of behavior under disruptions. We find that features extracted from the natural regime data can be successfully exploited to describe different disruption regimes, and that our framework can be used as a general tool for any similar complex transportation system.

  8. Volcano-tectonic earthquakes: A new tool for estimating intrusive volumes and forecasting eruptions

    NASA Astrophysics Data System (ADS)

    White, Randall; McCausland, Wendy

    2016-01-01

    We present data on 136 high-frequency earthquakes and swarms, termed volcano-tectonic (VT) seismicity, which preceded 111 eruptions at 83 volcanoes, plus data on VT swarms that preceded intrusions at 21 other volcanoes. We find that VT seismicity is usually the earliest reported seismic precursor for eruptions at volcanoes that have been dormant for decades or more, and precedes eruptions of all magma types from basaltic to rhyolitic and all explosivities from VEI 0 to ultraplinian VEI 6 at such previously long-dormant volcanoes. Because large eruptions occur most commonly during resumption of activity at long-dormant volcanoes, VT seismicity is an important precursor for the Earth's most dangerous eruptions. VT seismicity precedes all explosive eruptions of VEI ≥ 5 and most if not all VEI 4 eruptions in our data set. Surprisingly we find that the VT seismicity originates at distal locations on tectonic fault structures at distances of one or two to tens of kilometers laterally from the site of the eventual eruption, and rarely if ever starts beneath the eruption site itself. The distal VT swarms generally occur at depths almost equal to the horizontal distance of the swarm from the summit out to about 15 km distance, beyond which hypocenter depths level out. We summarize several important characteristics of this distal VT seismicity including: swarm-like nature, onset days to years prior to the beginning of magmatic eruptions, peaking of activity at the time of the initial eruption whether phreatic or magmatic, and large non-double couple component to focal mechanisms. Most importantly we show that the intruded magma volume can be simply estimated from the cumulative seismic moment of the VT seismicity from: Log10 V = 0.77 Log ΣMoment - 5.32, with volume, V, in cubic meters and seismic moment in Newton meters. Because the cumulative seismic moment can be approximated from the size of just the few largest events, and is quite insensitive to precise locations

  9. Voxel-Based Approach for Estimating Urban Tree Volume from Terrestrial Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Vonderach, C.; Voegtle, T.; Adler, P.

    2012-07-01

    The importance of single trees and the determination of related parameters has been recognized in recent years, e.g. for forest inventories or management. For urban areas an increasing interest in the data acquisition of trees can be observed concerning aspects like urban climate, CO2 balance, and environmental protection. Urban trees differ significantly from natural systems with regard to the site conditions (e.g. technogenic soils, contaminants, lower groundwater level, regular disturbance), climate (increased temperature, reduced humidity) and species composition and arrangement (habitus and health status) and therefore allometric relations cannot be transferred from natural sites to urban areas. To overcome this problem an extended approach was developed for a fast and non-destructive extraction of branch volume, DBH (diameter at breast height) and height of single trees from point clouds of terrestrial laser scanning (TLS). For data acquisition, the trees were scanned with highest scan resolution from several (up to five) positions located around the tree. The resulting point clouds (20 to 60 million points) are analysed with an algorithm based on voxel (volume elements) structure, leading to an appropriate data reduction. In a first step, two kinds of noise reduction are carried out: the elimination of isolated voxels as well as voxels with marginal point density. To obtain correct volume estimates, the voxels inside the stem and branches (interior voxels) where voxels contain no laser points must be regarded. For this filling process, an easy and robust approach was developed based on a layer-wise (horizontal layers of the voxel structure) intersection of four orthogonal viewing directions. However, this procedure also generates several erroneous "phantom" voxels, which have to be eliminated. For this purpose the previous approach was extended by a special region growing algorithm. In a final step the volume is determined layer-wise based on the extracted

  10. Advanced transportation system studies technical area 2 (TA-2): Heavy lift launch vehicle development. volume 3; Program Cost estimates

    NASA Technical Reports Server (NTRS)

    McCurry, J. B.

    1995-01-01

    The purpose of the TA-2 contract was to provide advanced launch vehicle concept definition and analysis to assist NASA in the identification of future launch vehicle requirements. Contracted analysis activities included vehicle sizing and performance analysis, subsystem concept definition, propulsion subsystem definition (foreign and domestic), ground operations and facilities analysis, and life cycle cost estimation. The basic period of performance of the TA-2 contract was from May 1992 through May 1993. No-cost extensions were exercised on the contract from June 1993 through July 1995. This document is part of the final report for the TA-2 contract. The final report consists of three volumes: Volume 1 is the Executive Summary, Volume 2 is Technical Results, and Volume 3 is Program Cost Estimates. The document-at-hand, Volume 3, provides a work breakdown structure dictionary, user's guide for the parametric life cycle cost estimation tool, and final report developed by ECON, Inc., under subcontract to Lockheed Martin on TA-2 for the analysis of heavy lift launch vehicle concepts.

  11. Feasibility of dual-low scheme combined with iterative reconstruction technique in acute cerebral infarction volume CT whole brain perfusion imaging.

    PubMed

    Wang, Tao; Gong, Yi; Shi, Yibing; Hua, Rong; Zhang, Qingshan

    2017-07-01

    The feasibility of application of low-concentration contrast agent and low tube voltage combined with iterative reconstruction in whole brain computed tomography perfusion (CTP) imaging of patients with acute cerebral infarction was investigated. Fifty-nine patients who underwent whole brain CTP examination and diagnosed with acute cerebral infarction from September 2014 to March 2016 were selected. Patients were randomly divided into groups A and B. There were 28 cases in group A [tube voltage, 100 kV; contrast agent, iohexol (350 mg I/ml), reconstructed by filtered back projection] and 31 cases in group B [tube voltage, 80 kV; contrast agent, iodixanol (270 mg I/ml), reconstructed by algebraic reconstruction technique]. The artery CT value, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), dose length product, effective dose (ED) of radiation and brain iodine intake of both groups were measured and statistically analyzed. Two physicians carried out kappa (κ) analysis on the consistency of image quality evaluation. The difference in subjective image quality evaluation between the groups was tested by χ(2). The differences in CT value, SNR, CNR, CTP and CT angiography subjective image quality evaluation between both groups were not statistically significant (P>0.05); the diagnosis rate of the acute infarcts between the two groups was not significantly different; while the ED and iodine intake in group B (dual low-dose group) were lower than group A. In conclusion, combination of low tube voltage and iterative reconstruction technique, and application of low-concentration contrast agent (270 mg I/ml) in whole brain CTP examination reduced ED and iodine intake without compromising image quality, thereby reducing the risk of contrast-induced nephropathy.

  12. Action of acetylstrophanthidin on experimental myocardial infarction.

    NASA Technical Reports Server (NTRS)

    Nola, G. T.; Pope, S. E.; Harrison, D. C.

    1972-01-01

    An experimental animal model with acute myocardial infarction of a size insufficient to produce profound heart failure or shock was used to study the effects of acute infarction on digitalis tolerance and the hemodynamic changes produced by moderate and large doses of acetylstrophanthidin. With acute myocardial infarction, digitalis toxic arrhythmias could be precipitated with significantly lower doses of digitalis than in animals without myocardial infarction. There was no precise correlation between the size of infarction and the toxic dose of glycoside. Coronary artery ligation produced a stable but relatively depressed circulatory state, as evidenced by lowered cardiac output and stroke volume and elevated systemic vascular resistance and left atrial mean pressure. When digitalis was infused, the following significant changes were observed at nontoxic doses: (1) elevation of aortic and left ventricular pressures; (2) further decline in cardiac output; and (3) decreased left atrial mean pressure.

  13. Action of acetylstrophanthidin on experimental myocardial infarction.

    NASA Technical Reports Server (NTRS)

    Nola, G. T.; Pope, S. E.; Harrison, D. C.

    1972-01-01

    An experimental animal model with acute myocardial infarction of a size insufficient to produce profound heart failure or shock was used to study the effects of acute infarction on digitalis tolerance and the hemodynamic changes produced by moderate and large doses of acetylstrophanthidin. With acute myocardial infarction, digitalis toxic arrhythmias could be precipitated with significantly lower doses of digitalis than in animals without myocardial infarction. There was no precise correlation between the size of infarction and the toxic dose of glycoside. Coronary artery ligation produced a stable but relatively depressed circulatory state, as evidenced by lowered cardiac output and stroke volume and elevated systemic vascular resistance and left atrial mean pressure. When digitalis was infused, the following significant changes were observed at nontoxic doses: (1) elevation of aortic and left ventricular pressures; (2) further decline in cardiac output; and (3) decreased left atrial mean pressure.

  14. Estimating Pinus palustris tree diameter and stem volume from tree height, crown area and stand-level parameters

    Treesearch

    C.A. Gonzalez-Benecke; Salvador A. Gezan; Lisa J. Samuelson; Wendell P. Cropper; Daniel J. Leduc; Timothy A. Martin

    2014-01-01

    Accurate and efficient estimation of forest growth and live biomass is a critical element in assessing potential responses to forest management and environmental change. The objective of this study was to develop models to predict longleaf pine tree diameter at breast height (dbh) and merchantable stem volume (V) using data obtained from field measurements. We used...

  15. Using FIA and GIS Data to Estimate Areas and Volumes of Potential Stream Management Zones and Road Beautifying Buffers

    Treesearch

    Michael Zasada; Chris J. Cieszewski; Roger C. Lowe; Jarek Zawadzki; Mike Clutter; Jacek P. Siry

    2005-01-01

    Georgia Stream Management Zones (SMZ) are voluntary and have an unknown extent and impact. We use FIA data, Landsat TM imagery, and GAP and other GIS data to estimate the acreages and volumes of these buffers. We use stream data classified into trout, perennial, and intermittent, combined with DEM files containing elevation values, to assess buffers with widths...

  16. Comparison of a fully mapped plot design to three alternative designs for volume and area estimates using Maine inventory data

    Treesearch

    Stanford L. Arner

    1998-01-01

    A fully mapped plot design is compared to three alternative designs using data collected for the recent inventory of Maine's forest resources. Like the fully mapped design, one alternative eliminates the bias of previous procedures, and should be less costly and more consistent. There was little difference in volume and area estimates or in sampling errors among...

  17. The United States Employment Service: A Conceptual Model of Outputs, Values, and Illustrative Estimations. Volume 1: Final Report.

    ERIC Educational Resources Information Center

    Weiner, Neil S.; And Others

    The conceptual framework behind the model of aggregate U.S. Employment Service (ES) productivity is described in this report (and the companion volume of appendixes) along with the illustrative estimates of ES productivity using the model. Chapter 1 introduces the question of productivity measurement in a social purpose. Chapter 2 contains a…

  18. The real estate factor: quantifying the impact of infarct location on stroke severity.

    PubMed

    Menezes, Nina M; Ay, Hakan; Wang Zhu, Ming; Lopez, Chloe J; Singhal, Aneesh B; Karonen, Jari O; Aronen, Hannu J; Liu, Yawu; Nuutinen, Juho; Koroshetz, Walter J; Sorensen, A Gregory

    2007-01-01

    The severity of the neurological deficit after ischemic stroke is moderately correlated with infarct volume. In the current study, we sought to quantify the impact of location on neurological deficit severity and to delineate this impact from that of volume. We developed atlases consisting of location-weighted values indicating the relative importance in terms of neurological deficit severity for every voxel of the brain. These atlases were applied to 80 first-ever ischemic stroke patients to produce estimates of clinical deficit severity. Each patient had an MRI and National Institutes of Health Stroke Scale (NIHSS) examination just before or soon after hospital discharge. The correlation between the location-based deficit predictions and measured neurological deficit (NIHSS) scores were compared with the correlation obtained using volume alone to predict the neurological deficit. Volume-based estimates of neurological deficit severity were only moderately correlated with measured NIHSS scores (r=0.62). The combination of volume and location resulted in a significantly better correlation with clinical deficit severity (r=0.79, P=0.032). The atlas methodology is a feasible way of integrating infarct size and location to predict stroke severity. It can estimate stroke severity better than volume alone.

  19. Sheep carcass composition estimated from Longissimus thoracis et lumborum muscle volume measured by in vivo real-time ultrasonography.

    PubMed

    Silva, S R; Guedes, C M; Santos, V A; Lourenço, A L; Azevedo, J M T; Dias-da-Silva, A

    2007-08-01

    The use of Longissimus thoracis et lumborum muscle (LM) volume measured in vivo by real-time ultrasonography (RTU) to estimate carcass composition was evaluated in 47 female sheep. Animals were scanned over six sites (7th, 9th, 11th and 13th thoracic vertebrae and 2nd and 4th lumbar vertebrae). After slaughter carcass weight (CW) and composition by dissection were determined. RTU volume measurements were calculated by multiplying the LM area at each site by the vertebra lengths. Equivalent measurements to those taken in vivo were obtained on the carcass using a digital camera and image analysis. The correlation between LM volume measured by RTU and in the carcass was high for all scans. LM volume was better in predicting carcass muscle than carcass fat. Lower determination coefficients were obtained between LM volume and carcass tissues expressed in % of CW. The best estimates of carcass tissues weights and proportions were obtained using the LM volume between the 2nd and the 4th lumbar vertebrae for all tissues. Multiple regression equations were fitted using live weight (LW) and LM volume to predict carcass composition. For all tissues, the best fit was obtained with two, three or four independent variables and the stepwise procedure was consistent in selecting LW to establish the prediction equations. Weights and proportions of muscle, subcutaneous fat, intermuscular fat and total fat were accurately predicted. These results indicate that Longissimus thoracis et lumborum muscle volume measured in vivo by RTU can be used to predict sheep carcass composition (muscle and fat).

  20. Descendant root volume varies as a function of root type: estimation of root biomass lost during uprooting in Pinus pinaster.

    PubMed

    Danjon, Frédéric; Caplan, Joshua S; Fortin, Mathieu; Meredieu, Céline

    2013-01-01

    Root systems of woody plants generally display a strong relationship between the cross-sectional area or cross-sectional diameter (CSD) of a root and the dry weight of biomass (DWd) or root volume (Vd) that has grown (i.e., is descendent) from a point. Specification of this relationship allows one to quantify root architectural patterns and estimate the amount of material lost when root systems are extracted from the soil. However, specifications of this relationship generally do not account for the fact that root systems are comprised of multiple types of roots. We assessed whether the relationship between CSD and Vd varies as a function of root type. Additionally, we sought to identify a more accurate and time-efficient method for estimating missing root volume than is currently available. We used a database that described the 3D root architecture of Pinus pinaster root systems (5, 12, or 19 years) from a stand in southwest France. We determined the relationship between CSD and Vd for 10,000 root segments from intact root branches. Models were specified that did and did not account for root type. The relationships were then applied to the diameters of 11,000 broken root ends to estimate the volume of missing roots. CSD was nearly linearly related to the square root of Vd, but the slope of the curve varied greatly as a function of root type. Sinkers and deep roots tapered rapidly, as they were limited by available soil depth. Distal shallow roots tapered gradually, as they were less limited spatially. We estimated that younger trees lost an average of 17% of root volume when excavated, while older trees lost 4%. Missing volumes were smallest in the central parts of root systems and largest in distal shallow roots. The slopes of the curves for each root type are synthetic parameters that account for differentiation due to genetics, soil properties, or mechanical stimuli. Accounting for this differentiation is critical to estimating root loss accurately.

  1. Hypertensive encephalopathy and cerebral infarction.

    PubMed

    Edvardsson, Bengt

    2014-01-01

    Hypertensive encephalopathy is one cause of posterior reversible encephalopathy syndrome. Hypertensive encephalopathy and cerebral infarction have only been reported in a few individual case reports. A 51-year-old woman presented with hypertensive encephalopathy. T2-weighted images from magnetic resonance imaging showed hyperintense lesions in both occipital and parietal lobes. Diffusion-weighted imaging showed that this represented cytotoxic oedema and perfusion magnetic resonance imaging revealed reduced blood volume and flow. The magnetic resonance imaging was repeated 5 months later and subtotal regression of theT2-hyperintensity had occurred. However, small bilateral infarcts were seen on T1-weighted images. Perfusion magnetic resonance imaging presented reduced blood volume and flow on the right side. The patient in this report had posterior reversible encephalopathy syndrome caused by hypertensive encephalopathy. Magnetic resonance imaging of the brain showed bilateral cytotoxic oedema that partially resolved and resulted in small infarcts. The imaging findings are compatible with posterior reversible encephalopathy syndrome with subtotal resolution and infarct evolution. The case report suggests that the presence of hypertensive encephalopathy and posterior reversible encephalopathy syndrome should alert clinicians and lead to prompt treatment in order to prevent cerebral damage.

  2. The mosquito ultra-low volume dispersion model for estimating environmental concentrations of insecticides used for adult mosquito management.

    PubMed

    Schleier, Jerome J; Peterson, Robert K D

    2014-09-01

    Computer models for pesticide drift are widely used tools by regulatory agencies to estimate the deposition of pesticides beyond the intended target area. Currently, there is no model in use that has been validated or verified as an accurate means of estimating concentrations of insecticides after ground-based ultra-low volume (ULV) applications used for adult mosquito management. To address the need for a validated model we created a spreadsheet-based model called Mosquito Ultra-Low Volume Dispersion (MULV-Disp) to aid in the adoption and to provide easier use of a validated model. We explain the origin, use, and utility of MULV-Disp, which can be used by regulatory agencies and other interested parties to estimate deposition of ULV insecticides.

  3. An Approach to the Use of Depth Cameras for Weed Volume Estimation

    PubMed Central

    Andújar, Dionisio; Dorado, José; Fernández-Quintanilla, César; Ribeiro, Angela

    2016-01-01

    The use of depth cameras in precision agriculture is increasing day by day. This type of sensor has been used for the plant structure characterization of several crops. However, the discrimination of small plants, such as weeds, is still a challenge within agricultural fields. Improvements in the new Microsoft Kinect v2 sensor can capture the details of plants. The use of a dual methodology using height selection and RGB (Red, Green, Blue) segmentation can separate crops, weeds, and soil. This paper explores the possibilities of this sensor by using Kinect Fusion algorithms to reconstruct 3D point clouds of weed-infested maize crops under real field conditions. The processed models showed good consistency among the 3D depth images and soil measurements obtained from the actual structural parameters. Maize plants were identified in the samples by height selection of the connected faces and showed a correlation of 0.77 with maize biomass. The lower height of the weeds made RGB recognition necessary to separate them from the soil microrelief of the samples, achieving a good correlation of 0.83 with weed biomass. In addition, weed density showed good correlation with volumetric measurements. The canonical discriminant analysis showed promising results for classification into monocots and dictos. These results suggest that estimating volume using the Kinect methodology can be a highly accurate method for crop status determination and weed detection. It offers several possibilities for the automation of agricultural processes by the construction of a new system integrating these sensors and the development of algorithms to properly process the information provided by them. PMID:27347972

  4. An Approach to the Use of Depth Cameras for Weed Volume Estimation.

    PubMed

    Andújar, Dionisio; Dorado, José; Fernández-Quintanilla, César; Ribeiro, Angela

    2016-06-25

    The use of depth cameras in precision agriculture is increasing day by day. This type of sensor has been used for the plant structure characterization of several crops. However, the discrimination of small plants, such as weeds, is still a challenge within agricultural fields. Improvements in the new Microsoft Kinect v2 sensor can capture the details of plants. The use of a dual methodology using height selection and RGB (Red, Green, Blue) segmentation can separate crops, weeds, and soil. This paper explores the possibilities of this sensor by using Kinect Fusion algorithms to reconstruct 3D point clouds of weed-infested maize crops under real field conditions. The processed models showed good consistency among the 3D depth images and soil measurements obtained from the actual structural parameters. Maize plants were identified in the samples by height selection of the connected faces and showed a correlation of 0.77 with maize biomass. The lower height of the weeds made RGB recognition necessary to separate them from the soil microrelief of the samples, achieving a good correlation of 0.83 with weed biomass. In addition, weed density showed good correlation with volumetric measurements. The canonical discriminant analysis showed promising results for classification into monocots and dictos. These results suggest that estimating volume using the Kinect methodology can be a highly accurate method for crop status determination and weed detection. It offers several possibilities for the automation of agricultural processes by the construction of a new system integrating these sensors and the development of algorithms to properly process the information provided by them.

  5. [Estimation of VOC emission from forests in China based on the volume of tree species].

    PubMed

    Zhang, Gang-feng; Xie, Shao-dong

    2009-10-15

    Applying the volume data of dominant trees from statistics on the national forest resources, volatile organic compounds (VOC) emissions of each main tree species in China were estimated based on the light-temperature model put forward by Guenther. China's VOC emission inventory for forest was established, and the space-time and age-class distributions of VOC emission were analyzed. The results show that the total VOC emissions from forests in China are 8565.76 Gg, of which isoprene is 5689.38 Gg (66.42%), monoterpenes is 1343.95 Gg (15.69%), and other VOC is 1532.43 Gg (17.89%). VOC emissions have significant species variation. Quercus is the main species responsible for emission, contributing 45.22% of the total, followed by Picea and Pinus massoniana with 6.34% and 5.22%, respectively. Southwest and Northeast China are the major emission regions. In specific, Yunnan, Sichuan, Heilongjiang, Jilin and Shaanxi are the top five provinces producing the most VOC emissions from forests, and their contributions to the total are 15.09%, 12.58%, 10.35%, 7.49% and 7.37%, respectively. Emissions from these five provinces occupy more than half (52.88%) of the national emissions. Besides, VOC emissions show remarkable seasonal variation. Emissions in summer are the largest, accounting for 56.66% of the annual. Forests of different ages have different emission contribution. Half-mature forests play a key role and contribute 38.84% of the total emission from forests.

  6. Position and volume estimation of atmospheric nuclear detonations from video reconstruction

    NASA Astrophysics Data System (ADS)

    Schmitt, Daniel T.

    Recent work in digitizing films of foundational atmospheric nuclear detonations from the 1950s provides an opportunity to perform deeper analysis on these historical tests. This work leverages multi-view geometry and computer vision techniques to provide an automated means to perform three-dimensional analysis of the blasts for several points in time. The accomplishment of this requires careful alignment of the films in time, detection of features in the images, matching of features, and multi-view reconstruction. Sub-explosion features can be detected with a 67% hit rate and 22% false alarm rate. Hotspot features can be detected with a 71.95% hit rate, 86.03% precision and a 0.015% false positive rate. Detected hotspots are matched across 57-109 degree viewpoints with 76.63% average correct matching by defining their location relative to the center of the explosion, rotating them to the alternative viewpoint, and matching them collectively. When 3D reconstruction is applied to the hotspot matching it completes an automated process that has been used to create 168 3D point clouds with 31.6 points per reconstruction with each point having an accuracy of 0.62 meters with 0.35, 0.24, and 0.34 meters of accuracy in the x-, y- and z-direction respectively. As a demonstration of using the point clouds for analysis, volumes are estimated and shown to be consistent with radius-based models and in some cases improve on the level of uncertainty in the yield calculation.

  7. Greater-than-Class C low-level radioactive waste characterization: Estimated volumes, radionuclide activities, and other characteristics

    SciTech Connect

    Hulse, R.A.

    1991-08-01

    Planning for storage or disposal of greater-than-Class C low-level radioactive waste (GTCC LLW) requires characterization of that waste to estimate volumes, radionuclide activities, and waste forms. Data from existing literature, disposal records, and original research were used to estimate the characteristics and project volumes and radionuclide activities to the year 2035. GTCC LLW is categorized as: nuclear utilities waste, sealed sources waste, DOE-held potential GTCC LLW; and, other generator waste. It has been determined that the largest volume of those wastes, approximately 57%, is generated by nuclear power plants. The Other Generator waste category contributes approximately 10% of the total GTCC LLW volume projected to the year 2035. Waste held by the Department of Energy, which is potential GTCC LLW, accounts for nearly 33% of all waste projected to the year 2035; however, no disposal determination has been made for that waste. Sealed sources are less than 0.2% of the total projected volume of GTCC LLW.

  8. Can endocranial volume be estimated accurately from external skull measurements in great-tailed grackles (Quiscalus mexicanus)?

    PubMed Central

    Palmstrom, Christin R.

    2015-01-01

    There is an increasing need to validate and collect data approximating brain size on individuals in the field to understand what evolutionary factors drive brain size variation within and across species. We investigated whether we could accurately estimate endocranial volume (a proxy for brain size), as measured by computerized tomography (CT) scans, using external skull measurements and/or by filling skulls with beads and pouring them out into a graduated cylinder for male and female great-tailed grackles. We found that while females had higher correlations than males, estimations of endocranial volume from external skull measurements or beads did not tightly correlate with CT volumes. We found no accuracy in the ability of external skull measures to predict CT volumes because the prediction intervals for most data points overlapped extensively. We conclude that we are unable to detect individual differences in endocranial volume using external skull measurements. These results emphasize the importance of validating and explicitly quantifying the predictive accuracy of brain size proxies for each species and each sex. PMID:26082858

  9. Estimating the eruptive volume of a large pyroclastic body: the Otowi Member of the Bandelier Tuff, Valles caldera, New Mexico

    NASA Astrophysics Data System (ADS)

    Cook, Geoffrey W.; Wolff, John A.; Self, Stephen

    2016-02-01

    The 1.60 Ma caldera-forming eruption of the Otowi Member of the Bandelier Tuff produced Plinian and coignimbrite fall deposits, outflow and intracaldera ignimbrite, all of it deposited on land. We present a detailed approach to estimating and reconstructing the original volume of the eroded, partly buried large ignimbrite and distal ash-fall deposits. Dense rock equivalent (DRE) volume estimates for the eruption are 89 + 33/-10 km3 of outflow ignimbrite and 144 ± 72 km3 of intracaldera ignimbrite. Also, there was at least 65 km3 (DRE) of Plinian fall when extrapolated distally, and 107 + 40/-12 km3 of coignimbrite ash was "lost" from the outflow sheet to form an unknown proportion of the distal ash fall. The minimum total volume is 216 km3 and the maximum is 550 km3; hence, the eruption overlaps the low end of the super-eruption spectrum (VEI ˜8.0). Despite an abundance of geological data for the Otowi Member, the errors attached to these estimates do not allow us to constrain the proportions of intracaldera (IC), outflow (O), and distal ash (A) to better than a factor of three. We advocate caution in applying the IC/O/A = 1:1:1 relation of Mason et al. (2004) to scaling up mapped volumes of imperfectly preserved caldera-forming ignimbrites.

  10. Effect of weight loss on magnetic resonance imaging estimation of liver fat and volume in patients with nonalcoholic steatohepatitis.

    PubMed

    Patel, Niraj S; Doycheva, Iliana; Peterson, Michael R; Hooker, Jonathan; Kisselva, Tatiana; Schnabl, Bernd; Seki, Ekihiro; Sirlin, Claude B; Loomba, Rohit

    2015-03-01

    Little is known about how weight loss affects magnetic resonance imaging (MRI) of liver fat and volume or liver histology in patients with nonalcoholic steatohepatitis (NASH). We measured changes in liver fat and liver volume associated with weight loss by using an advanced MRI method. We analyzed data collected from a previous randomized controlled trial in which 43 adult patients with biopsy-proven NASH underwent clinical evaluation, biochemical tests, and MRI and liver biopsy analyses at the start of the study and after 24 weeks. We compared data between patients who did and did not have at least 5% decrease in body mass index (BMI) during the study period. Ten of 43 patients had at least a 5% decrease in BMI during the study period. These patients had a significant decrease in liver fat, which was based on MRI proton density fat fraction estimates (18.3% ± 7.6% to 13.6% ± 13.6%, P = .03), a relative 25.5% reduction. They also had a significant decrease in liver volume (5.3%). However, no significant changes in levels of alanine aminotransferase or aspartate aminotransferase were observed with weight loss. Thirty-three patients without at least 5% decrease in BMI had insignificant increases in estimated liver fat fraction and liver volume. A reduction in BMI of at least 5% is associated with significant decrease in liver fat and volume in patients with biopsy-proven NASH. These data should be considered in assessing effect size in studies of patients with nonalcoholic fatty liver disease or obesity that use MRI-estimated liver fat and volume as end points. Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.

  11. Factors affecting uncertainty in lung nodule volume estimation with CT: comparisons of findings from two estimation methods in a phantom study

    NASA Astrophysics Data System (ADS)

    Li, Qin; Gavrielides, Marios A.; Zeng, Rongping; Myers, Kyle J.; Sahiner, Berkman; Petrick, Nicholas

    2015-03-01

    This work aimed to compare two different types of volume estimation methods (a model-based and a segmentationbased method) in terms of identifying factors affecting measurement uncertainty. Twenty-nine synthetic nodules with varying size, radiodensity, and shape were placed in an anthropomorphic thoracic phantom and scanned with a 16- detector row CT scanner. Ten repeat scans were acquired using three exposures and two slice collimations, and were reconstructed with varying slice thicknesses. Nodule volumes were estimated from the reconstructed data using a matched-filter and a segmentation approach. Log transformed volumes were used to obtain measurement error with truth obtained through micro-CT. ANOVA and multiple linear regression were applied to measurement error to identify significant factors affecting volume estimation for each method. Root mean square of measurement errors (RMSE) for meaningful subgroups, repeatability coefficients (RC) for different imaging protocols, and reproducibility coefficients (RDC) for thin and thick collimation conditions were evaluated. Results showed that for both methods, nodule size, shape and slice thickness were significant factors. Collimation was significant for the matched-filter method. RMSEs for matched-filter measurements were in general smaller than segmentation. To achieve RMSE on the order of 15% or less for {5, 8, 9, 10mm} nodules, the corresponding maximum allowable slice thicknesses were {3, 5, 5, 5mm} for the matched-filter and {0.8, 3, 3, 3mm} for the segmentation method. RCs showed similar patterns for both methods, increasing with slice thickness. For 8-10mm nodules, the measurements were highly repeatable provided the slice thickness was ≤3mm, regardless of method and across varying acquisition conditions. RDCs were lower for thin collimation than thick collimation protocols. While RDC of matched filter volume estimation results was always lower than segmentation results, for 8-10mm nodules with thin

  12. Diameter growth, survival, and volume estimates for trees in Indiana and Illinois.

    Treesearch

    W. Brad Smit