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Sample records for resolution first-pass perfusion

  1. Parallel imaging for first-pass myocardial perfusion.

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    Irwan, Roy; Lubbers, Daniël D; van der Vleuten, Pieter A; Kappert, Peter; Götte, Marco J W; Sijens, Paul E

    2007-06-01

    Two parallel imaging methods used for first-pass myocardial perfusion imaging were compared in terms of signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and image artifacts. One used adaptive Time-adaptive SENSitivity Encoding (TSENSE) and the other used GeneRalized Autocalibrating Partially Parallel Acquisition (GRAPPA), which are both applied to a gradient-echo sequence. Both methods were tested on 12 patients with coronary artery disease. The order of perfusion sequences was inverted in every other patient. Image acquisition was started during the administration of a contrast bolus followed by a 20-ml saline flush (3 ml/s), and the next perfusion was started at least 15 min thereafter using an identical bolus. An acceleration rate of 2 was used in both methods, and acquisition was performed during breath-holding. Significantly higher SNR, CNR and image quality were obtained with GRAPPA images than with TSENSE images. GRAPPA, however, did not yield a higher CNR when applied after the second bolus. GRAPPA perfusion imaging produced larger differences between subjects than did TSENSE. Compared to TSENSE, GRAPPA produced significantly better CNR on the first bolus. More consistent SNR and CNR were obtained from TSENSE images than from GRAPPA images, indicating that the diagnostic value of TSENSE may be better.

  2. Improved first-pass spiral myocardial perfusion imaging with variable density trajectories.

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    Salerno, Michael; Sica, Christopher; Kramer, Christopher M; Meyer, Craig H

    2013-11-01

    To develop and evaluate variable-density spiral first-pass perfusion pulse sequences for improved efficiency and off-resonance performance and to demonstrate the utility of an apodizing density compensation function (DCF) to improve signal-to-noise ratio (SNR) and reduce dark-rim artifact caused by cardiac motion and Gibbs Ringing. Three variable density spiral trajectories were designed, simulated, and evaluated in 18 normal subjects, and in eight patients with cardiac pathology on a 1.5T scanner. By using a DCF, which intentionally apodizes the k-space data, the sidelobe amplitude of the theoretical point spread function (PSF) is reduced by 68%, with only a 13% increase in the full-width at half-maximum of the main-lobe when compared with the same data corrected with a conventional variable-density DCF, and has an 8% higher resolution than a uniform density spiral with the same number of interleaves and readout duration. Furthermore, this strategy results in a greater than 60% increase in measured SNR when compared with the same variable-density spiral data corrected with a conventional DCF (P density spiral pulse sequences using an apodized DCF produce high-quality first-pass perfusion images with minimal dark-rim and off-resonance artifacts, high SNR and contrast-to-noise ratio, and good delineation of resting perfusion abnormalities. Copyright © 2012 Wiley Periodicals, Inc.

  3. An initial study on the feasibility of diagnosing myocardial ischemia with CT first-pass myocardial perfusion imaging at rest

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    汪奇

    2013-01-01

    Objective To assess the feasibility and accuracy of CT first-pass myocardial perfusion imaging(CT first-pass MPI)at rest for diagnosis of myocardial ischemia.Results of adenosine-induced myocardial perfusion scintigraphy(MPS)

  4. Dynamic Perfusion CT Assessment of the Blood-Brain Barrier Permeability : First Pass versus Delayed Acquisition

    NARCIS (Netherlands)

    Dankbaar, J. W.; Hom, J.; Schneider, T.; Cheng, S. -C.; Lau, B. C.; van der Schaaf, I.; Virmani, S.; Pohlman, S.; Dillon, W. P.; Wintermark, M.

    2008-01-01

    BACKGROUND AND PURPOSE: The Patlak model has been applied to first-pass perfusion CT (PCT) data to extract information on blood-brain barrier permeability (BBBP) to predict hemorrhagic transformation in patients with acute stroke. However, the Patlak model was originally described for the delayed st

  5. Dynamic Perfusion CT Assessment of the Blood-Brain Barrier Permeability : First Pass versus Delayed Acquisition

    NARCIS (Netherlands)

    Dankbaar, J. W.; Hom, J.; Schneider, T.; Cheng, S. -C.; Lau, B. C.; van der Schaaf, I.; Virmani, S.; Pohlman, S.; Dillon, W. P.; Wintermark, M.

    2008-01-01

    BACKGROUND AND PURPOSE: The Patlak model has been applied to first-pass perfusion CT (PCT) data to extract information on blood-brain barrier permeability (BBBP) to predict hemorrhagic transformation in patients with acute stroke. However, the Patlak model was originally described for the delayed st

  6. Evaluation of allograft perfusion by radionuclide first-pass study in renal failure following renal transplantation

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    Baillet, G.; Ballarin, J.; Urdaneta, N.; Campos, H.; Vernejoul, P. de; Fermanian, J.; Kellershohn, C.; Kreis, H.

    1986-04-01

    To assess the diagnostic value of indices measured on a first-pass curve, we performed 72 radionuclide renal first-pass studies (RFP) in 21 patients during the early weeks following renal allograft transplantation. The diagnosis was based on standard clinical and biochemical data and on fine needle aspiration biopsy (FNAB) of the transplant. Aortic and renal first-pass curves were filtered using a true low-pass filter and five different indices of renal perfusion were computed, using formulae from the literature. Statistical analysis performed on the aortic and renal indices indicated excellent reproducibility of the isotopic study. Although renal indices presented a rather large scatter, they all discriminated well between normal and rejection. Three indices have a particularly good diagnostic value. In the discrimination between rejection and Acute Tubular Necrosis (ATN), only one index gave satisfying results. The indices, however, indicate that there are probably ATN with an alternation of renal perfusion and rejection episodes where perfusion is almost intact. We conclude that radionuclide first-pass study allows accurate and reproducible quantitation of renal allograft perfusion. The measured parameters are helpful to follow up the course of a post-transplantation renal failure episode and to gain more insight into renal ischemia following transplantation.

  7. Optimized Saturation Pulse Train for Human First-Pass Myocardial Perfusion Imaging at 7T

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    Tao, Yuehui; Hess, Aaron T; Keith, Graeme A; Rodgers, Christopher T; Liu, Alexander; Francis, Jane M; Neubauer, Stefan; Robson, Matthew D

    2015-01-01

    Purpose To investigate whether saturation using existing methods developed for 3T imaging is feasible for clinical perfusion imaging at 7T, and to propose a new design of saturation pulse train for first-pass myocardial perfusion imaging at 7T. Methods The new design of saturation pulse train consists of four hyperbolic-secant (HS8) radiofrequency pulses, whose peak amplitudes are optimized for a target range of static and transmit field variations and radiofrequency power deposition restrictions measured in the myocardium at 7T. The proposed method and existing methods were compared in simulation, phantom, and in vivo experiments. Results In healthy volunteer experiments without contrast agent, average saturation efficiency with the proposed method was 97.8%. This is superior to results from the three previously published methods at 86/95/90.8%. The first series of human first-pass myocardial perfusion images at 7T have been successfully acquired with the proposed method. Conclusion Existing saturation methods developed for 3T imaging are not optimal for perfusion imaging at 7T. The proposed new design of saturation pulse train can saturate effectively, and with this method first-pass myocardial perfusion imaging is feasible in humans at 7T. Magn Reson Med 73:1450–1456, 2015. © 2014 The Authors. Magnetic Resonance in Medicine Published by Wiley Periodicals, Inc. on behalf of International Society of Medicine in Resonance. PMID:24753130

  8. Myocardial first-pass perfusion imaging with hybrid-EPI: frequency-offsets and potential artefacts

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    Ferreira Pedro F

    2012-06-01

    Full Text Available Abstract Background First-pass myocardial perfusion is often imaged with a tailored hybrid centric interleaved echo-planar-imaging sequence, providing rapid image acquisition with good contrast enhancement. The centric interleaved phase-encode order minimises the effective time-of-echo but it is sensitive to frequency-offsets. This short article aims to show possible artefacts that might originate with this sequence, in the context of first-pass perfusion imaging, when frequency-offsets are present. Non-uniform magnitude modulation effects were also analysed. Methods Numerical and phantom simulations were used to illustrate the effects of frequency-offsets and non-uniform magnitude modulation with this sequence in a typical perfusion protocol. In vivo data was post-processed to analyse the h-EPI’s sensitivity to the frequency-offsets. Results The centric phase-order was shown to be highly sensitive to frequency-offsets due to its symmetrical phase slope. Resulting artefacts include blurring, and splitting of the image into two identical copies along the phase-encode direction. It was also shown that frequency-offsets can introduce signal loss and ghosting of the right ventricle signal into the myocardium. The in vivo results were confirmed by numerical and phantom simulations. Magnitude modulation effects were found to be small. Conclusions Imaging first-pass myocardial perfusion with an hybrid centric echo-planar-imaging sequence can be corrupted with ghosting and splitting of the image due to frequency-offsets.

  9. Spatio-temporal simulation of first pass drug perfusion in the liver.

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    Lars Ole Schwen

    2014-03-01

    Full Text Available The liver is the central organ for detoxification of xenobiotics in the body. In pharmacokinetic modeling, hepatic metabolization capacity is typically quantified as hepatic clearance computed as degradation in well-stirred compartments. This is an accurate mechanistic description once a quasi-equilibrium between blood and surrounding tissue is established. However, this model structure cannot be used to simulate spatio-temporal distribution during the first instants after drug injection. In this paper, we introduce a new spatially resolved model to simulate first pass perfusion of compounds within the naive liver. The model is based on vascular structures obtained from computed tomography as well as physiologically based mass transfer descriptions obtained from pharmacokinetic modeling. The physiological architecture of hepatic tissue in our model is governed by both vascular geometry and the composition of the connecting hepatic tissue. In particular, we here consider locally distributed mass flow in liver tissue instead of considering well-stirred compartments. Experimentally, the model structure corresponds to an isolated perfused liver and provides an ideal platform to address first pass effects and questions of hepatic heterogeneity. The model was evaluated for three exemplary compounds covering key aspects of perfusion, distribution and metabolization within the liver. As pathophysiological states we considered the influence of steatosis and carbon tetrachloride-induced liver necrosis on total hepatic distribution and metabolic capacity. Notably, we found that our computational predictions are in qualitative agreement with previously published experimental data. The simulation results provide an unprecedented level of detail in compound concentration profiles during first pass perfusion, both spatio-temporally in liver tissue itself and temporally in the outflowing blood. We expect our model to be the foundation of further spatially

  10. A relative quantitative assessment of myocardial perfusion by first-pass technique: animal study

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    Chen, Jun; Zhang, Zhang; Yu, Xuefang; Zhou, Kenneth J.

    2015-03-01

    The purpose of this study is to quantitatively assess the myocardial perfusion by first-pass technique in swine model. Numerous techniques based on the analysis of Computed Tomography (CT) Hounsfield Unit (HU) density have emerged. Although these methods proposed to be able to assess haemodynamically significant coronary artery stenosis, their limitations are noticed. There are still needs to develop some new techniques. Experiments were performed upon five (5) closed-chest swine. Balloon catheters were placed into the coronary artery to simulate different degrees of luminal stenosis. Myocardial Blood Flow (MBF) was measured using color microsphere technique. Fractional Flow Reserve (FFR) was measured using pressure wire. CT examinations were performed twice during First-pass phase under adenosine-stress condition. CT HU Density (HUDCT) and CT HU Density Ratio (HUDRCT) were calculated using the acquired CT images. Our study presents that HUDRCT shows a good (y=0.07245+0.09963x, r2=0.898) correlation with MBF and FFR. In receiver operating characteristic (ROC) curve analyses, HUDRCT provides excellent diagnostic performance for the detection of significant ischemia during adenosine-stress as defined by FFR indicated by the value of Area Under the Curve (AUC) of 0.927. HUDRCT has the potential to be developed as a useful indicator of quantitative assessment of myocardial perfusion.

  11. Whole tumour perfusion of peripheral lung carcinoma: evaluation with first-pass CT perfusion imaging at 64-detector row CT

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    Li, Y. [Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan (China); Yang, Z.-G. [Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan (China); National Key Laboratory of Biotherapy Center, West China Hospital, Sichuan University, Chengdu, Sichuan (China)], E-mail: yangzg1117@yahoo.com.cn; Chen, T.-w.; Deng, Y.-p.; Yu, J.-q.; Li, Z.-l. [Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan (China)

    2008-06-15

    Aim: To prospectively assess the feasibility of a whole-tumour perfusion technique using 64-detector row computed tomography (CT) and to analyse the variation of CT perfusion parameters in different histological types, sizes, and metastases in patients with peripheral lung carcinoma. Methods and materials: Ninety-seven pathologically proved peripheral lung carcinomas (less than 5 cm in largest diameter) underwent dynamic contrast-enhanced CT using a 64-detector row CT machine. Small amounts of iodinated contrast medium with a sharp bolus profile (50 ml, 6-7 ml/s), and 12 repeated fast acquisitions encompassing the entire tumour lesion were adopted to quantify perfusion of the whole-tumour during first-pass of contrast medium. Four kinetic parameters, including perfusion, peak enhancement intensity (PEI), time to peak (TTP), and blood volume (BV), were measured and statistically compared among different histological types, sizes, and metastases. Results: Mean values for perfusion, PEI, TTP, and BV of the 97 lung carcinomas were 57.5 {+-} 45.4 ml/min/ml (range 5.9-243 ml/min/ml), 53.4 {+-} 40.6 HU (range 10.3-234.4 HU), 34 {+-} 11 s (range 11-60 s), and 30.1 {+-} 21.7 ml/100 g (range 3.9-113.4 ml/100 g), respectively. No statistical differences were found between the histological types regarding the perfusion parameters (p > 0.05). Perfusion, PEI, and BV of stage T2 tumours were significantly lower than those of stage T1 tumours (all p < 0.05), whereas no statistically significant differences was found between other stages of tumours (all p > 0.05). Perfusion of the tumours with distant metastasis was significantly higher than that of the tumours without distant metastasis (p < 0.05), but there was no statistically significant difference between nodal metastasis positive and negative groups (p > 0.05). Conclusion: The present study of first-pass perfusion imaging using 64-detector row CT could provide a feasible method for assessment of whole-tumour perfusion. CT

  12. Three dimensional first-pass myocardial perfusion imaging at 3T: feasibility study

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    Pohost Gerald M

    2008-12-01

    Full Text Available Abstract Background In patients with ischemic heart disease, accurate assessment of the extent of myocardial perfusion deficit may be important in predicting prognosis of clinical cardiac outcomes. The aim of this study was to compare the ability of three dimensional (3D and of two dimensional (2D multi-slice myocardial perfusion imaging (MPI using cardiovascular magnetic resonance (CMR in determining the size of defects, and to demonstrate the feasibility of 3D MPI in healthy volunteers at 3 Tesla. Methods A heart phantom was used to compare the accuracy of 3D and 2D multi-slice MPI in estimating the volume fraction of seven rubber insets which simulated transmural myocardial perfusion defects. Three sets of cross-sectional planes were acquired for 2D multi-slice imaging, where each set was shifted along the partition encoding direction by ± 10 mm. 3D first-pass contrast-enhanced (0.1 mmol/kg Gd-DTPA MPI was performed in three volunteers with sensitivity encoding for six-fold acceleration. The upslope of the myocardial time-intensity-curve and peak SNR/CNR values were calculated. Results Mean/standard deviation of errors in estimating the volume fraction across the seven defects were -0.44/1.49%, 2.23/2.97%, and 2.59/3.18% in 3D, 2D 4-slice, and 2D 3-slice imaging, respectively. 3D MPI performed in healthy volunteers produced excellent quality images with whole left ventricular (LV coverage. Peak SNR/CNR was 57.6 ± 22.0/37.5 ± 19.7 over all segments in the first eight slices. Conclusion 3D performed better than 2D multi-slice MPI in estimating the size of perfusion defects in phantoms. Highly accelerated 3D MPI at 3T was feasible in volunteers, allowing whole LV coverage with excellent image quality and high SNR/CNR.

  13. First-pass perfusion computed tomography: Initial experience in differentiating adrenal adenoma from metastasis

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    Qiao Zhongwei [Department of Radiology, Rui Jin Hospital, Shanghai Jiao Tong, University School of Medicine, Shanghai 200025 (China); Department of Radiology, Children' s Hospital of Fudan University, Shanghai 201102 (China); Xia Chunmei [Department of Physiology and Pathophysiology, Shanghai Medical, College, Fudan University, Shanghai 200032 (China); Zhu Yanbo; Shi Weiping [Department of Radiology, Rui Jin Hospital, Shanghai Jiao Tong, University School of Medicine, Shanghai 200025 (China); Miao Fei [Department of Radiology, Rui Jin Hospital, Shanghai Jiao Tong, University School of Medicine, Shanghai 200025 (China)], E-mail: fmiao818@gmail.com

    2010-03-15

    Objective: To differentiate adrenal adenoma from metastasis in patients using perfusion computed tomography (PCT) imaging. Methods: Thirty-two patients with adrenal masses underwent first-pass PCT imaging. Of these patients, twenty-one were diagnosed with adrenal adenoma, and the others with metastases. Perfusion maps of blood volume (BV), blood flow (BF), mean transit time (MTT) and permeability surface-area production (PS) were generated with an Advantage Windows workstation using the CT perfusion 3.0 software (General Electric Medical Systems, Milwaukee, WI). Histopathologic sections immunostained for CD34 were quantitatively evaluated for microvessel density (MVD). Results: The perfusion parameters such as BV, BF and PS were statistically significant different between the two groups, with adenomas showing higher mean BV (12.18 versus 3.86), BF (97.51 versus 45.99) and PS (21.73 versus 10.93) compared with metastases (p < 0.05). For BV, a cutoff point of 7.30 was found to have a sensitivity of 95.2% and a specificity of 100% to differentiate between adenoma and metastasis. The sensitivity and specificity were 81.0 and 80.0%, respectively, for BF with a cutoff point of 71.96; and 85.7 and 86.7%, respectively, for PS with a cutoff point of 12.70 to differentiate adenoma and metastasis. A comparison of MVD counts from adenomas with those from metastases showed a significant difference (p < 0.05). However, no significant differences were observed in the four perfusion parameters and MVD between lipid rich and lipid poor adenomas. Conclusion: PCT may be useful for evaluating the neovascularization of adrenal masses and differentiating adenoma from metastasis on the basis of PCT parameters. Adenomas show higher BV, BF and PS compared with metastases. According our data, the optimal threshold BV is 7.30, resulting in a sensitivity of 95.2% and a specificity of 100% for the differentiation of adenoma from metastasis. Adrenal adenomas have similar hemodynamic profiles

  14. Advanced NSCLC First Pass Perfusion at 64-slice CT: Reproducibility of Volume-based Quantitative Measurement

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    Jie HU

    2010-05-01

    Full Text Available Background and objective The aim of this study is to explore the reproducibility of volume-based quantitative measurement of non-small cell lung cancer (NSCLC perfusion at 64-slice CT. Methods Fourteen patients with proved advanced NSCLC were enrolled in this dynamic first pass volume-based CT perfusion (CTP study (8×5 mm collimation, and they underwent the second scan within 24 h. According to the longest diameters, those patients were classified to ≤3 cm and >3 cm groups, and each group had 7 patients. Intraclass correlation coefficient (ICC and Bland-Altman statistics were used to evaluate the reproducibility of CTP imaging. Results In both groups of advanced NSCLC, the reproducibility with BF, BV, and PS values were good (ICC >0.75 for all, but mean transit time (MTT values. For advanced NSCLC (≤3 cm, repeatability coefficient (RC values with blood flow (BF, blood volume (BV, MTT and permeability surface area product (PS values were 56%, 45%, 114%, and 78%, respectively, and the 95% change intervals of RC were -39%-53%, -29%-62%, -83%-145%, and -57%-98%, respectively. For advanced NSCLC (>3 cm, those values were 46%, 30%, 59%, and 33%, respectively, and the 95% change intervals of RC were -48%-45%, -33%-26%, -54%-64%, and -18%-48%. Conclusion There is greater reproducibility of tumor size >3 cm than that of ≤3 cm. BF and BV could be addressed for reliable clinical application in antiangiogenesis therapeutic monitoring with advanced NSCLC patients.

  15. Three-dimensional first-pass myocardial perfusion MRI using a stack-of-spirals acquisition.

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    Shin, Taehoon; Nayak, Krishna S; Santos, Juan M; Nishimura, Dwight G; Hu, Bob S; McConnell, Michael V

    2013-03-01

    Three-dimensional cardiac magnetic resonance perfusion imaging is promising for the precise sizing of defects and for providing high perfusion contrast, but remains an experimental approach primarily due to the need for large-dimensional encoding, which, for traditional 3DFT imaging, requires either impractical acceleration factors or sacrifices in spatial resolution. We demonstrated the feasibility of rapid three-dimensional cardiac magnetic resonance perfusion imaging using a stack-of-spirals acquisition accelerated by non-Cartesian k-t SENSE, which enables entire myocardial coverage with an in-plane resolution of 2.4 mm. The optimal undersampling pattern was used to achieve the largest separation between true and aliased signals, which is a prerequisite for k-t SENSE reconstruction. Flip angle and saturation recovery time were chosen to ensure negligible magnetization variation during the transient data acquisition. We compared the proposed three-dimensional perfusion method with the standard 2DFT approach by consecutively acquiring both data during each R-R interval in cardiac patients. The mean and standard deviation of the correlation coefficients between time intensity curves of three-dimensional versus 2DFT were 0.94 and 0.06 across seven subjects. The linear correlation between the two sets of upslope values was significant (r = 0.78, P < 0.05).

  16. TU-G-204-03: Dynamic CT Myocardial Perfusion Measurement Using First Pass Analysis and Maximum Slope Models

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    Hubbard, L; Ziemer, B; Sadeghi, B; Javan, H; Lipinski, J; Molloi, S [University of California, Irvine, CA (United States)

    2015-06-15

    Purpose: To evaluate the accuracy of dynamic CT myocardial perfusion measurement using first pass analysis (FPA) and maximum slope models. Methods: A swine animal model was prepared by percutaneous advancement of an angioplasty balloon into the proximal left anterior descending (LAD) coronary artery to induce varying degrees of stenosis. Maximal hyperaemia was achieved in the LAD with an intracoronary adenosine drip (240 µg/min). Serial microsphere and contrast (370 mg/mL iodine, 30 mL, 5mL/s) injections were made over a range of induced stenoses, and dynamic imaging was performed using a 320-row CT scanner at 100 kVp and 200 mA. The FPA CT perfusion technique was used to make vessel-specific myocardial perfusion measurements. CT perfusion measurements using the FPA and maximum slope models were validated using colored microspheres as the reference gold standard. Results: Perfusion measurements using the FPA technique (P-FPA) showed good correlation with minimal offset when compared to perfusion measurements using microspheres (P- Micro) as the reference standard (P -FPA = 0.96 P-Micro + 0.05, R{sup 2} = 0.97, RMSE = 0.19 mL/min/g). In contrast, the maximum slope model technique (P-MS) was shown to underestimate perfusion when compared to microsphere perfusion measurements (P-MS = 0.42 P -Micro −0.48, R{sup 2} = 0.94, RMSE = 3.3 mL/min/g). Conclusion: The results indicate the potential for significant improvements in accuracy of dynamic CT myocardial perfusion measurement using the first pass analysis technique as compared with the standard maximum slope model.

  17. A Prospective Evaluation of T2-Weighted First-Pass Perfusion MR Imaging In Diagnosing Breast Neoplasms

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    XiaoJuanUu; RenyouZhai; TaoJiang; LiWang

    2004-01-01

    OBJECTIVE To compare the results from breast cancer patients who undergo T2-weighted first-pass perfusion imaging after dynamic contrast-enhanced T1-weighted imaging during the same examination,and to evaluate if T2-weighted imaging can provide additional diagnostic information over that obtained with Tl-weiahted imaaina.METHODS Twenty-nine patients with breast lesions verified by pathology (benign 12, malignant 17) underwent MR imaging with dynamic contrast-enhanced Tl-weighted imaging of the entire breasts,immediately followed by 6-sections of T2-weighted first-pass perfusion imaging of the lesions. The diagnostic indices were acquired by individual 3D Tl-weighted enhancement rate criterion and the T2 signalintensity loss rate criterion. The sensitivity and specificity were calculated and the 2 methods were compared.RESULTS With the dynamic contrast-enhanced T1-weighted imaging there was a significant differences breast lesions (t=2.563, P=0.016)overlap between the signal intensitybetween the benign and malignant However we found a considerable increase in the carcinomas and thatin the benign lesions, for a sensitivity of 94% and a specificity of 25%.With T2-weighted first-pass perfusion imaging, there was a very significant difference between the benign and malignant breast lesions(t=4.777,P<0.001), and the overlap between the signal intensity decrease in the carcinomas and that of the benign lesions on the T2-weighted images was less pronounced than the overlap in the T1-weighted images, for a sensitivity of 88% and a specificity of 75%.CONCLUSION T2-weighted first-pass perfusion imaging may help differentiate between benign and malignant breast lesions with a higher level of specificity. The combination of T1-weighted and T2-weighted imaging is feasible in a single patient examination and may improve breast MR imaging.

  18. [Peripheral lung adenocarcinoma versus squamous cell carcinoma: evaluation with first-pass perfusion imaging using 64-detector row CT].

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    Li, Yuan; Yang, Zhigang; Chen, Tianwu; Yu, Jianqun; Deng, Yuping; Li, Zhenlin

    2009-04-01

    The aim of this study was to elucidate the characteristics of time attenuation curve and CT perfusion parameters for pulmonary adenocarcinomas and squamous cell carcinomas. 58 cases of pulmonary adenocarcinomas and 27 cases of squamous cell carcinomas underwent first pass CT perfusion imaging with 64-row MDCT. Data were analyzed using commercial software to generate time attenuation curve (TAC) and CT perfusion parameters, including perfusion, peak enhanced (PE), time to peak (TTP), and blood volume (BV). For TAC, there were 36.2% of type I and 63.8% of type II in adenocarcinomas, while there were 22.2% of type I and 77.8% of type II in squamous cell carcinomas. There was not significant difference (P>0.05). Perfusion, PE, TTP and BV of adenocarcinomas were 63.2 +/- 45.4 ml x min(-1) x ml(-1), 60.2 +/- 46.6 Hu, 34.8 +/- 10.2 s and 34.3 +/- 23.6 ml x 100 g(-1), respectively, while 54.3 +/- 50.2 ml x min(-1) x ml(-1), 48.5 +/- 34.9 Hu, 36.1 +/- 11.2 s and 27.6 +/- 21.7 ml x 100 g(-1), for squamous cell carcinoma, respectively. No significant differences were found between groups (P>0.05). No significant differences in TAC and CT perfusion parameters were found between adenocarcinomas and squamous cell carcinomas.

  19. First experiences with contrast-enhanced first-pass MR perfusion imaging in patients with primary, benign cardiac masses and tumour-like lesions

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    Mohrs, Oliver K. [Darmstadt Radiology, Department of Cardiovascular Imaging at Alice-Hospital, Darmstadt (Germany); German Cancer Research Center (DKFZ), Department of Radiology, Heidelberg (Germany); Voigtlaender, Thomas [Cardiovascular Center Bethanien (CCB), Frankfurt/Main (Germany); Petersen, Steffen E. [John Radcliffe Hospital, University of Oxford, OCMR, Oxford (United Kingdom); Zander, Matthias [Darmstadt Center of Cardiology, Darmstadt (Germany); Schulze, Thomas [Siemens Medical Solutions, Frankfurt/Main (Germany); Pottmeyer, Anselm [Darmstadt Radiology, Department of Cardiovascular Imaging at Alice-Hospital, Darmstadt (Germany); Kauczor, Hans-Ulrich [German Cancer Research Center (DKFZ), Department of Radiology, Heidelberg (Germany)

    2008-08-15

    The aim of this study was to evaluate the diagnostic value of contrast-enhanced first-pass perfusion MRI in patients with suspected cardiac masses and tumour-like lesions. Twenty patients underwent contrast-enhanced first-pass saturation-recovery steady-state-free-precession perfusion MRI in addition to clinical MRI. Eleven diagnostic parameters were analysed blinded in consensus by three observers: localisation (paracardiac/mural/intracavitary), malignancy (benign/malignant) and first-pass enhancement pattern (homogeneous/heterogeneous as well as non-perfused/hypoperfused/iso-perfused/ hyperperfused). The results were compared to combined references comprising histology, cytology, medical and surgical reports, echocardiography, chest X-ray, coronary angiography and regular MRI. Also, we analysed if additional first-pass perfusion confirmed, changed or reduced the number of differential diagnoses compared to clinical MRI. All cardiac masses or tumour-like lesions were correctly localised and scored as benign lesions. For homogeneous perfused lesions the sensitivity, specificity, positive and negative predictive value was 94/100/100/67%, 100/94/67/100% for heterogeneous perfused lesions, 92/100/100/88% for non-perfused, 100/94/75/100 for hypoperfused, 100/100/100/100% for hyperperfused and for isoperfused lesions. In 17/2/1 cases perfusion MRI confirmed, reduced or increased the number of potential differentials. First-pass perfusion MRI provides valuable information in patients with benign cardiac masses or tumour-like lesions. Further experience is needed to underline these preliminary observations. (orig.)

  20. First-pass extraction fraction of iodine-123 labeled perfusion tracers in living primate brain

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    Moerlein, S.M.; Perlmutter, J.S.; Raichle, M.E. [Washington Univ., St. Louis, MO (United States). Edward Mallinckrodt Inst. of Radiology]|[Washington Univ., St. Louis, MO (United States). School of Medicine; Welch, M.J. [Washington Univ., St. Louis, MO (United States). Edward Mallinckrodt Inst. of Radiology

    1994-08-01

    The cerebral extraction and retention of three radioiodinated SPECT perfusion tracers were measured using residue detection in a baboon. A permeability-surface area product PS` with special relevance to SPECT was calculated from the retention of tracer in the brain after 10 min. PS` differs from the traditional PS value, which is calculated from the tracer clearance curve at 2 min. The PS` values ranged from 50 to 95 mL/min/100 g, decreased in the order [{sup 123}I]IMP > [{sup 123}I]iodoperidol=[{sup 123}I] HIPDM, and did not differ for specific activities of 10 MBq/mmol to 74 TBq/mmol. These radioiodinated compounds exhibited extraction characteristics superior to those of [{sup 99m}Tc]HMPAO but underestimated cerebral blood flow when flows were above 20-30 mL/min/100 g, underscoring the need for development of a more ideal SPECT perfusion tracer. (author).

  1. A pilot study on diagnosis of coronary artery disease using computed tomography first-pass myocardial perfusion imaging at rest

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    Qi WANG; Jing QIN; Lu-yue GAI; Yun-dai CHEN; Wei DONG; Zhi-wei GUAN; Zhi-guo WANG; Zhi-jun SUN; Jia-he TIAN

    2011-01-01

    Background: Although computed tomography coronary angiography (CTCA) can identify coronary stenosis, little data exists on the ability of multislice computed tomography (MSCT) to detect myocardial perfusion defects at rest. Methods: In 33 patients with diagnosed or suspected coronary artery disease (CAD), CTCA using retrospective electrocardiography (ECG) gating at rest and invasive coronary angiography (ICA) was performed. The 2D myocardial images were reconstructed in diastolic and systolic phases using the same raw data for CTCA. CT values of the myocardium were used as an estimate of myocardial enhancement, which were shown by color mapping. Myocardial ischemia was defined as a pattern of transient endocardial hypo-enhancement at systole and normal enhancement at diastole. The results of ICA were taken as the reference standard. Results: When a diameter reduction of more than 50% in ICA was used as diagnostic criteria of CAD, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CT first-pass myocardial perfusion imaging (MPI) at rest were 0.85, 0.67, 0.92, and 0.50 per patient, respectively, and 0.58, 0.93, 0.85, and 0.76 per vessel, respectively. Conclusions: CT first-pass MPI at rest could detect CAD patients, which could become a practical and convenient way to detect ischemia, consequently offering the ability for MSCT to act as a "one stop shop" for the diagnosis of CAD.

  2. Assessment of hepatocellular carcinoma vascularity before and after transcatheter arterial chemoembolization by using first pass perfusion weighted MR imaging

    Institute of Scientific and Technical Information of China (English)

    Jun-Gong Zhao; Gan-Sheng Feng; Xiang-Quan Kong; Xin Li; Ming-Hua Li; Ying-Sheng Cheng

    2004-01-01

    AIM: To assess the vascularity of hepatocellular carcinoma (HCC)before and after transcatheter arterial chemoembolization (TACE) with the quantitative parameters obtained by first pass perfusion weighted MR imaging (FP-MRI).METHODS: Seventeen consecutive patients with one to three lesions in liver underwent FP-MRI before treatment.FP-MRI was also performed one, three, six, nine months,and one year after TACE. The baseline signal intensity (SO)of pre-TACE and one month after TACE was analyzed, the vascularity of HCC assessed by steepest slope of the signal intensity versus time curves (SS) was blindly correlated with their DSA feature and clinical outcome.RESULT: No significant difference was found on baseline signal intensity (SO) between pre-TACE and one month after TACE (F=0.309, P=0.583), The SS (mean, 32% per second) of lesion one month after TACE was lower than that of pre-TACE (mean, 69% per second), but with no statistical significance (F=3.067, P=0.092). When local recurrence occurred, the time intensity curves became steeper. The vascularity of HCC before and after TACE graded by SS closely correlated with that by DSA (K=0.453, P<0.05).CONCLUSION: FP-MRI is a useful criterion for selecting effective interventional treatment for patients with HCC in their initial treatment and during follow up.

  3. The additional value of first pass myocardial perfusion imaging during peak dose of dobutamine stress cardiac MRI for the detection of myocardial ischemia

    NARCIS (Netherlands)

    Lubbers, Daniel D.; Janssen, Caroline H. C.; Kuijpers, Dirkjan; Van Dijkman, Paul R. M.; Overbosch, Jelle; Willems, Tineke P.; Oudkerk, Matthijs

    2008-01-01

    Purpose of this study was to assess the additional value of first pass myocardial perfusion imaging during peak dose of dobutamine stress Cardiac-MR (CMR). Dobutamine Stress CMR was performed in 115 patients with an inconclusive diagnosis of myocardial ischemia on a 1.5 T system (Magnetom Avanto, Si

  4. Whole tumour first-pass perfusion using a low-dose method with 64-section multidetector row computed tomography in oesophageal squamous cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Chen Tianwu, E-mail: twchenscu@yahoo.com.cn [Sichuan Province Key Laboratory of Medical Imaging, and Department of Radiology, Affiliated Hospital of North Sichuan Medical College, 63 Wen Hua Lu, Nanchong, Sichuan 637000 (China); Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Yang Zhigang, E-mail: yangzg6666@yahoo.com.cn [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Dong Zhihui, E-mail: dongzhih@163.com [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Li Yuan, E-mail: dr.liyuan@163.com [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Yao Jin, E-mail: shelleyyao@163.com [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Wang Qiling, E-mail: xiaohongmao99@126.com [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Qian Lingling, E-mail: moneylinglingch1999@126.com [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China)

    2011-11-15

    Purpose: To propose a low-dose method at tube current-time product of 50 mAs for whole tumour first-pass perfusion of oesophageal squamous cell carcinoma using 64-section multidetector row computed tomography (MDCT), and to assess the original image quality and accuracy of perfusion parameters. Materials and methods: Fifty-nine consecutive patients with confirmed oesophageal squamous cell carcinomas were enrolled into our study, and underwent whole tumour first-pass perfusion scan with 64-section MDCT at 50 mAs. Image data were statistically reviewed focusing on original image quality demonstrated by image-quality scores and signal-to-noise (S/N) ratios; and perfusion parameters including perfusion (PF, in ml/min/ml), peak enhanced density (PED, in HU), time to peak (TTP, in seconds) and blood volume (BV, in ml/100 g) for the tumour. To test the interobserver agreement of perfusion measurements, perfusion analyses were repeatedly performed. Results: Original image-quality scores were 4.71 {+-} 0.49 whereas S/N ratios were 5.21 {+-} 2.05, and the scores were correlated with the S/N ratios (r = 0.465, p < 0.0001). Mean values for PF, PED, TTP and BV of the tumour were 33.27 {+-} 24.15 ml/min/ml, 24.06 {+-} 9.87 HU, 29.42 {+-} 8.61 s, and 12.45 {+-} 12.22 ml/100 g, respectively. Intraclass correlation coefficient between the replicated measurements of each perfusion parameter was greater than 0.99, and mean difference of the replicated measurements of each parameter was close to zero. Conclusion: Whole tumour first-pass perfusion with 64-section MDCT at low-dose radiation could be reproducible to assess microcirculation in oesophageal squamous cell carcinoma without compromising subjective original image quality of the tumour.

  5. Whole tumour quantitative measurement of first-pass perfusion of oesophageal squamous cell carcinoma using 64-row multidetector computed tomography: Correlation with microvessel density

    Energy Technology Data Exchange (ETDEWEB)

    Chen Tianwu, E-mail: twchenscu@yahoo.com.cn [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Sichuan Province Key Laboratory of Medical Imaging, and Department of Radiology, Affiliated Hospital of North Sichuan Medical College, 63 Wen Hua Lu, Nanchong, Sichuan 637007 (China); Yang Zhigang, E-mail: yangzg6666@yahoo.com.cn [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Wang Qiling, E-mail: xiaohongmao99@126.com [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Li Yuan, E-mail: dr.liyuan@163.com [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Qian Lingling, E-mail: moneylinglingch1999@126.com [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Chen Huijiao, E-mail: joan-ch@sohu.com [Department of Pathology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China)

    2011-08-15

    Purpose: To assess correlations between whole tumour first-pass perfusion parameters obtained with 64-row multidetector computed tomography (MDCT), and microvessel density (MVD) in oesophageal squamous cell carcinoma. Materials and Methods: Thirty-one consecutive patients with surgically confirmed oesophageal squamous cell carcinomas were enrolled into our study. All the patients underwent whole tumour first-pass perfusion scan with 64-row MDCT. Perfusion parameters, including perfusion (PF), peak enhanced density (PED), blood volume (BV), and time to peak (TTP) were measured using Philips perfusion software. Postoperative tumour specimens were assessed for MVD. Pearson correlation coefficient tests were performed to determine correlations between each perfusion parameter and MVD. Results: Mean values for PF, PED, BV and TTP of the whole tumour were 28.85 {+-} 20.29 ml/min/ml, 23.16 {+-} 8.09 HU, 12.13 {+-} 5.21 ml/100 g, and 35.05 {+-} 13.85 s, respectively. Mean MVD in whole tumour at magnification (x200) was 15.75 {+-} 4.34 microvessel/tumour sample (vessels/0.723 mm{sup 2}). PED and BV were correlated with MVD (r = 0.651 and r = 0.977, respectively, all p < 0.05). However, PF and TTP were not correlated with MVD (r = 0.070 and r = 0.100, respectively, all p > 0.05). Conclusion: The BV value of first-pass perfusion CT could reflect MVD in oesophageal squamous cell carcinoma, and can be an indicator for evaluating the tumour angiogenesis.

  6. Quantitative assessment of first-pass perfusion using a low-dose method at multidetector CT in oesophageal squamous cell carcinoma: Correlation with VEGF expression

    Energy Technology Data Exchange (ETDEWEB)

    Chen, T.-W. [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China) and Sichuan Province Key Laboratory of Medical Imaging and Department of Radiology, Affiliated Hospital of North Sichuan Medical College, 63 Wen Hua Lu, Nanchong, Sichuan 637000 (China); Yang, Z.-G., E-mail: yangzg1117@yahoo.com.cn [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Chen, H.-J. [Department of Pathology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Li, Y.; Tang, S.-S.; Yao, J.; Dong, Z.-H. [Department of Radiology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); He, D. [Department of Pathology, West China Hospital of Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China)

    2012-08-15

    Aim: To investigate the correlation between vascular endothelial cell growth factor (VEGF) expression and first-pass perfusion parameters at multidetector computed tomography (MDCT) using a low-dose technique, and to determine how to discriminate VEGF positivity from VEGF negativity by perfusion CT in oesophageal squamous cell carcinomas. Materials and methods: Thirty-two patients with oesophageal squamous cell carcinomas underwent first-pass perfusion with 64-section MDCT at 50 mAs. Perfusion parameters, including perfusion, peak enhanced density (PED), time to peak (TTP), and blood volume (BV), were measured. Postoperative specimens were assessed for VEGF expression. Correlation tests were performed to determine the associations between each CT perfusion parameter and VEGF expression. The cut-off values of perfusion parameters were obtained statistically to discriminate VEGF positivity from VEGF negativity. Results: Mean perfusion, PED, TTP, and BV were 38.47 {+-} 30.26 ml/min/ml, 24.68 {+-} 9.65 HU, 28.35 {+-} 9.03 s, and 11.82 {+-} 6.06 ml/100 g, respectively. PED or BV were significantly higher in the VEGF-positive group than in the VEGF-negative group (all p < 0.05), but no significant difference in perfusion or TTP was found between the VEGF-positive and VEGF-negative groups (all p > 0.05). In VEGF positivity, PED and BV were correlated with VEGF expression (r = 0.576 and 0.765, respectively; all p < 0.05), whereas perfusion and TTP were not (r = 0.361 and 0.239, respectively; all p > 0.05). A threshold of BV (10.23 ml/100 g) achieved a sensitivity of 94.4%, and a specificity of 92.9% for discriminating VEGF positivity from VEGF negativity. Conclusion: BV could reflect tumour VEGF expression, and could be an indicator for evaluating angiogenesis in oesophageal tumours.

  7. Measurement of blood–brain barrier permeability in acute ischemic stroke using standard first-pass perfusion CT data ☆

    OpenAIRE

    Nguyen, Giang Truong; Coulthard, Alan; Wong, Andrew; Sheikh, Nabeel; Henderson, Robert; O'Sullivan, John D.; Reutens, David C.

    2013-01-01

    Background and purpose Increased blood–brain barrier permeability is believed to be associated with complications following acute ischemic stroke and with infarct expansion. Measurement of blood–brain barrier permeability requires a delayed image acquisition methodology, which prolongs examination time, increasing the likelihood of movement artefacts and radiation dose. Existing quantitative methods overestimate blood–brain barrier permeability when early phase CT perfusion data are used. The...

  8. Adenosine-stress dynamic real-time myocardial perfusion CT and adenosine-stress first-pass dual-energy myocardial perfusion CT for the assessment of acute chest pain: Initial results

    Energy Technology Data Exchange (ETDEWEB)

    Weininger, Markus [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Department of Medicine, Division of Cardiology, Medical University of South Carolina, Charleston, SC (United States); Ramachandra, Ashok [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Fink, Christian [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Rowe, Garrett W.; Costello, Philip [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Henzler, Thomas [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany)

    2012-12-15

    Purpose: Recent innovations in CT enable the evolution from mere morphologic imaging to dynamic and functional testing. We describe our initial experience performing myocardial stress perfusion CT in a clinical population with acute chest pain. Methods and materials: Myocardial stress perfusion CT was performed on twenty consecutive patients (15 men, 5 women; mean age 65 ± 8 years) who presented with acute chest pain and were clinically referred for stress/rest SPECT and cardiac MRI. Prior to CT each patient was randomly assigned either to Group A or to Group B in a consecutive order (10 patients per group). Group A underwent adenosine-stress dynamic real-time myocardial perfusion CT using a novel “shuttle” mode on a 2nd generation dual-source CT. Group B underwent adenosine-stress first-pass dual-energy myocardial perfusion CT using the same CT scanner in dual-energy mode. Two experienced observers visually analyzed all CT perfusion studies. CT findings were compared with MRI and SPECT. Results: In Group A 149/170 myocardial segments (88%) could be evaluated. Real-time perfusion CT (versus SPECT) had 86% (84%) sensitivity, 98% (92%) specificity, 94% (88%) positive predictive value, and 96% (92%) negative predictive value in comparison with perfusion MRI for the detection of myocardial perfusion defects. In Group B all myocardial segments were available for analysis. Compared with MRI, dual-energy myocardial perfusion CT (versus SPECT) had 93% (94%) sensitivity, 99% (98%) specificity, 92% (88%) positive predictive value, and 96% (94%) negative predictive value for detecting hypoperfused myocardial segments. Conclusion: Our results suggest the clinical feasibility of myocardial perfusion CT imaging in patients with acute chest pain. Compared to MRI and SPECT both, dynamic real-time perfusion CT and first-pass dual-energy perfusion CT showed good agreement for the detection of myocardial perfusion defects.

  9. Prevalence of first-pass myocardial perfusion defects detected by contrast-enhanced dual-source CT in patients with non-ST segment elevation acute coronary syndromes

    Energy Technology Data Exchange (ETDEWEB)

    Schepis, Tiziano; Achenbach, Stephan; Marwan, Mohamed; Muschiol, Gerd; Ropers, Dieter; Daniel, Werner G.; Pflederer, Tobias [University of Erlangen, Department of Internal Medicine 2 (Cardiology), Erlangen (Germany)

    2010-07-15

    To investigate the prevalence and diagnostic value of first-pass myocardial perfusion defects (PD) visualised by contrast-enhanced multidetector computed tomography (MDCT) in patients admitted for a first acute coronary syndrome (ACS). Thirty-eight patients with non-ST segment elevation myocardial infarction (NSTEMI) or unstable angina (UA) and scheduled for percutaneous coronary intervention underwent dual-source CT immediately before catheterisation. CT images were analysed for the presence of any PD by using a 17-segment model. Results were compared with peak cardiac troponin-I (cTnI) and angiography findings. PD were seen in 21 of the 24 patients with NSTEMI (median peak cTnI level 7.07 ng/mL; range 0.72-37.07 ng/mL) and in 2 of 14 patients with UA. PD corresponded with the territory of the infarct-related artery in 20 out of 22 patients. In a patient-based analysis, sensitivity, specificity, negative and positive predictive values of any PD for predicting NSTEMI were 88%, 86%, 80% and 91%. Per culprit artery, the respective values were 86%, 75%, 80% and 83%. In patients with non-ST segment elevation ACS, first-pass myocardial PD in contrast-enhanced MDCT correlate closely with the presence of myocardial necrosis, as determined by increases in cTnI levels. (orig.)

  10. Assessment of the acute effects of glucocorticoid treatment on coronary microembolization using cine, first-pass perfusion, and delayed enhancement MRI.

    Science.gov (United States)

    Jin, Hang; Yun, Hong; Ma, Jian-ying; Chen, Zhang-wei; Chang, Shu-fu; Ge, Mei-ying; Zeng, Meng-su

    2016-04-01

    To assess the acute effects of methylprednisone treatment (MPT) on coronary microembolization (CME) by cardiac cine, first-pass perfusion, and delayed gadolinium enhancement magnetic resonance imaging (DE-MRI) in an experimental swine model. Microembolization was established by intracoronary infusion of microspheres into the left anterior artery. Swine received placebo (n = 12) or methylprednisolone (n = 10, 30 mg/kg) intravenously 30 minutes before microembolization. Perfusion and DE-MRI was performed 6 hours after microembolization. Cine MR images of pre-/post-CME were obtained using 1.5T scanner. Cine MRI demonstrated relative amelioration of the post-CME myocardial contractile dysfunction in the glucocorticoid-treated group compared to the placebo group (P < 0.001). Post-CME target myocardial perfusion parameters decreased in both groups after microembolization. The extent of these decreases were the same for the embolized-to-control area ratio of maximum upslope (P = 0.245; 95% confidence interval of the difference [CID], -0.041/0.148) and time to peak ratio (P = 0.122; 95% CID, -0.201/0.026); however, the maximum signal intensity was higher in the glucocorticoid-treated group (P = 0.012; 95% CID, 0.023/0.156). DE-MRI revealed patchy hyperenhancement in all placebo pigs (n = 12/12) after microembolization, but no hyperenhanced regions in the glucocorticoid-pretreated pigs (n = 0/10). Standard, readily available, cardiac MRI techniques are useful in demonstrating post-CME myocardial dysfunction and the acute effects of glucocorticoid treatment on CME. Glucocorticoid pretreatment improves myocardial contractile dysfunction, prevents hyperenhancement, and partially ameliorates the decline of myocardial perfusion in the embolized area. © 2015 Wiley Periodicals, Inc.

  11. Differentiation between malignant and benign solitary pulmonary nodules: Use of volume first-pass perfusion and combined with routine computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Shan, Fei, E-mail: shanfeiqz@gmail.com [Department of Radiology, Third Affiliated Hospital of Suzhou University, 185, Juqian Road, Changzhou, Zip Code: 213003 (China); Zhang, Zhiyong, E-mail: zhangzy@fudan.edu.cn [Department of Radiology, Zhongshan Hospital Fudan University, 180, Fenglin Road, Shanghai, Zip Code: 200032 (China); Xing, Wei, E-mail: suzhxingwei@126.com [Department of Radiology, Third Affiliated Hospital of Suzhou University, 185, Juqian Road, Changzhou, Zip Code: 213003 (China); Qiu, Jianguo, E-mail: step9999@sina.com [Department of Radiology, Third Affiliated Hospital of Suzhou University, 185, Juqian Road, Changzhou, Zip Code: 213003 (China); Yang, Shan, E-mail: yang.shan@zs-hospital.sh.cn [Department of Radiology, Zhongshan Hospital Fudan University, 180, Fenglin Road, Shanghai, Zip Code: 200032 (China); Wang, Jian, E-mail: wang.jian@zs-hospital.sh.cn [Department of Radiology, Zhongshan Hospital Fudan University, 180, Fenglin Road, Shanghai, Zip Code: 200032 (China); Jiang, Yaping, E-mail: jiang.yaping@zs-hospital.sh.cn [Department of Radiology, Zhongshan Hospital Fudan University, 180, Fenglin Road, Shanghai, Zip Code: 200032 (China); Chen, Gang, E-mail: chen.gang@zs-hospital.sh.cn [Department of Radiology, Zhongshan Hospital Fudan University, 180, Fenglin Road, Shanghai, Zip Code: 200032 (China)

    2012-11-15

    Purpose: To evaluate the capability of first-pass volume perfusion computed tomography (PCT) for differentiation of solitary pulmonary nodules (SPNs) and to compare that of combination of PCT and routine CT with CT alone for the differentiation. Materials and methods: Our institutional review board approved this study and informed consent was obtained. With nine excluded, 65 consecutive patients having a SPN with histopathologic proof or follow-up underwent a 30 s PCT using the deconvolution model were evaluated. Kruskal-Wallis tests and receiver operating characteristics (ROC) analysis were underwent. Four radiologists assessed nodules independently and retrospectively. Diagnostic capability was compared for CT alone and PCT plus CT. ROC analysis, McNemar test, and weighted kappa statistics were performed. Results: Significant differences were found in parameters between malignant and benign nodules (p < 0.0001 for blood flow, blood volume, and permeability surface area product), SPNs were more likely to be malignant by using threshold values of more than 55 ml/100 g/min, 2.5 ml/100 g, and 10 ml/100 g/min, respectively. PCT plus CT was significantly better in overall sensitivity (93%, p = 0.004) and accuracy (94%, p = 0.003) compared to CT alone, not specificity (96%). Area under the curve for ROC analyses of PCT plus CT was significantly larger than that of CT alone (p = 0.018). Mean weighted kappa for PCT plus CT was 0.715, that for CT alone was 0.447. Conclusion: Volume first-pass PCT can distinguish SPNs. Using PCT plus routine CT may be more sensitive and accurate for differentiating malignant from benign nodules than CT alone and allows more confidence and constancy.

  12. Changes of tumor microcirculation after transcatheter arterial chemoembolization:First pass perfusion MR imaging and Chinese ink casting in a rabbit model

    Institute of Scientific and Technical Information of China (English)

    Jun-Gong Zhao; Gan-Sheng Feng; Xiang-Quan Kong; Xin Li; Ming-Hua Li; Ying-Sheng Cheng

    2004-01-01

    AIM: To observe the change of tumor microcirculation after transcatheter arterial chemoembolization (TACE) with bletilla microspheres by using first pass perfusion MR imaging (FP) and Chinese ink casting.METHODS: VX2 carcinoma cells were surgically implanted into the left and right lobes of liver of 30 New Zealand white rabbits, which were divided into 3 groups at random. Emulsion of lipiodol mixed with mitomycin C, and 5-FU bletilla microspheres were injected into the hepatic artery respectively, and saline was used as control agent. MR imaging was performed with turbo-flash sequence 14 d after tumor implantation and 7 d after interventional therapy. The steepest slopes (SS) of the signal intensity versus time curves were created for quantitative analysis, 7.5% Chinese ink gelatin solution was injected through ascending artery (17 cases) or portal vein (2 cases) for lesion microvessel area (MVA) measurement after the last MRI examination.The correlation between perfusion imaging and MVA was studied blindly.RESULTS: The SS values at the rim of tumor in lipiodol group (mean, 49% per second) and bletilla group (mean,35% per second) were significantly decreased (P<0.05) as compared with control group (mean, 124% per second), no difference was found between lipiodol and bletilla groups (P>0.05). In lipiodol group, the MVAs (24 974±11 836 μm2) in the center of the tumor were significantly smaller than those of the control group (35 510±15 675 μm2) (P<0.05),while the MVAs (80 031±22 745 μm2) around the tumor were significantly increased because small and dense plexuses appeared around the tumor which correlated to intense reaction of granulation tissue. None of the vessels was seen in the tumor in bletilla group, the peripheral MVAs of the tumor were significantly smaller than those of the control group (P<0.05) and lipiodol group (P<0.05). There was a good correlation between SS and MVAs in control group (rs, 0.985, P<0.0001) and bletilla group (rs, 0

  13. The regional myocardial microvascular dysfunction differences in hypertrophic cardiomyopathy patients with or without left ventricular outflow tract obstruction: Assessment with first-pass perfusion imaging using 3.0-T cardiac magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hua-yan [Department of Radiology, National Key Laboratory of Biotherapy, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Yang, Zhi-gang, E-mail: yangzg666@163.com [Department of Radiology, National Key Laboratory of Biotherapy, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Sun, Jia-yu; Wen, Ling-yi; Zhang, Ge; Zhang, Shuai [Department of Radiology, National Key Laboratory of Biotherapy, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Guo, Ying-kun [Department of Radiology, West China Second University Hospital, Sichuan University (China)

    2014-04-15

    Purpose: To assess regional myocardial microvascular dysfunction differences in hypertrophic cardiomyopathy (HCM) patients with or without left ventricular outflow tract obstruction using 3.0-T cardiac magnetic resonance (CMR) first-pass perfusion imaging. Materials and methods: Forty-two HCM patients, including 25 HCM patients with left ventricular outflow tract obstruction (HOCM), 17 HCM patients without left ventricular outflow tract obstruction (NOHCM), and 14 healthy subjects underwent CMR. The left ventricular (LV) function, left ventricular end-diastolic wall thickness (EDTH), and diameter of left ventricular outflow tract (LVOT) were measured and calculated. Based on the signal–time curve of the first-pass myocardium perfusion imaging, perfusion parameters including upslope, time to peak, and peak intensity, were assessed and compared by using one-way analysis of variance and independent t tests. Results: On the first-pass perfusion imaging, lower upslope and peak intensity and longer time to peak were found in HCM patients compared with normal subjects (all p < 0.05). In contrast to the NOHCM group, the average time to peak of the HOCM group was increased (13.30 ± 4.82 s vs 16.28 ± 4.90 s, p < 0.05), but first-pass perfusion upslope was reduced (4.96 ± 2.55 vs 2.58 ± 0.77, p < 0.05). According to the bull's-eye model, the HOCM group's average thickness of basal segments was thicker than the NOHCM group, especially the anteroseptal, inferolateral, and anterior wall values, with a corresponding lower first-pass perfusion upslope than the NOHCM group (all p < 0.05). A significant correlation was observed between first-pass perfusion upslope and LV EDTH (r = −0.551, p < 0.001) and LVOT diameter (r = 0.472, p < 0.001). Conclusions: The regional myocardial microvascular dysfunction differences in hypertrophic cardiomyopathy (HCM) patients with or without left ventricular outflow tract obstruction can be detected with first-pass perfusion CMR

  14. Diagnostic Performance of First-Pass Myocardial Perfusion Imaging without Stress with Computed Tomography (CT) Compared with Coronary CT Angiography Alone, with Fractional Flow Reserve as the Reference Standard.

    Science.gov (United States)

    Osawa, Kazuhiro; Miyoshi, Toru; Miki, Takashi; Koyama, Yasushi; Sato, Shuhei; Kanazawa, Susumu; Ito, Hiroshi

    2016-01-01

    Coronary computed tomography angiography (CCTA) in combination with first-pass CT myocardial perfusion imaging (MPI) has a better diagnostic performance than CCTA alone, compared with invasive coronary angiography as the reference standard. The aim of this study was to investigate the additional diagnostic value of first-pass CT-MPI without stress for detecting hemodynamic significance of coronary stenosis, compared with invasive fractional flow reserve (FFR). We recruited 53 patients with suspected coronary artery disease undergoing both CCTA and first-pass CT-MPI without stress and invasive FFR, and 75 vessels were analyzed. We used the same raw data for CCTA and CT-MPI. First-pass CT-MPI was reconstructed by examining the diastolic signal densities as a bull's eye map. Invasive FFR CT-MPI and CCTA alone was 0.81 (0.73-0.90) and 0.70 (0.61-0.81), respectively (P = 0.036). CCTA plus first-pass CT-MPI without stress showed 0.73 sensitivity, 0.74 specificity, 0.53 positive predictive value, and 0.87 negative predictive value for detecting hemodynamically significant coronary stenosis. First-pass CT-MPI without stress correctly reclassified 38% of CCTA false-positive vessels as true negative. First-pass CT-MPI without stress combined with CCTA demonstrated excellent diagnostic accuracy, compared with invasive FFR as the reference standard. This technique could complement CCTA for diagnosis of coronary artery disease.

  15. MR Diagnosis of a Pulmonary Embolism: Comparison of P792 and Gd-DOTA for First-Pass Perfusion MRI and Contrast-Enhanced 3D MRA in a Rabbit Model

    Energy Technology Data Exchange (ETDEWEB)

    Keilholz, Shella D. [Emory University and Georgia Institute of Technology, Atlanta (United States); Bozlar, Ugur; Fujiwara, Naomi; Mata, Jaime F.; Berr, Stuart S.; Hagspiel, Klaus D. [Gulhane Military Medical Academy, Ankara (Turkmenistan); Corot, Claire [Guerbet Research, Aulnay-sous-Bois (France)

    2009-10-15

    To compare P792 (gadomelitol, a rapid clearance blood pool MR contrast agent) with gadolinium-tetraazacyclododecanetetraacetic acid (Gd- DOTA), a standard extracellular agent, for their suitability to diagnose a pulmonary embolism (PE) during a first-pass perfusion MRI and 3D contrastenhanced (CE) MR angiography (MRA). A perfusion MRI or CE-MRA was performed in a rabbit PE model following the intravenous injection of a single dose of contrast agent. The time course of the pulmonary vascular and parenchymal enhancement was assessed by measuring the signal in the aorta, pulmonary artery, and lung parenchyma as a function of time to determine whether there is a significant difference between the techniques. CE-MRA studies were evaluated by their ability to depict the pulmonary vasculature and following defects between 3 seconds and 15 minutes after a triple dose intravenous injection of the contrast agents. The P792 and Gd-DOTA were equivalent in their ability to demonstrate PE as perfusion defects on first pass imaging. The signal from P792 was significantly higher in vasculature than that from Gd-DOTA between the first and the tenth minutes after injection. The results suggest that a CE-MRA PE could be reliably diagnosed up to 15 minutes after injection. P792 is superior to Gd-DOTA for the MR diagnosis of PE.

  16. Experimental investigation of the perfusion of the liver with non-diffusible tracers: Differentiation of the arterial and portal-venous components by deconvolution analysis of first-pass time-activity curves

    Energy Technology Data Exchange (ETDEWEB)

    Szabo, Z.; Torsello, G.; Reifenrath, C.; Porschen, R.; Vosberg, H.

    1988-10-01

    The transfer function of the liver perfusion is an idealised time-activity curve that could be registered over the liver if a non-diffusible tracer would be injected directly into the abdominal aorta and no tracer recirculation would occur. The reproducibility of the transfer function was experimentally investigated in foxhounds. Both the routes of tracer application and the modes of data evaluation were varied and the perfusion was investigated under physiological and pathological conditions. The transfer function was calculated by deconvolution analysis of first-pass time-activity curves using the matrix regularisation method. The transfer function showed clearly distinguishable arterial and portal-venous components. Repeated peripheral venous and central aortic applications resulted in reproducible curves. In addition to the arterial and portal-venous components the subcomponents of the portal-venous component could also be identified in the transfer function after ligation of the appropriate vessels. The accuracy of the mathematical procedure was tested by computer simulations. The simulation studies demonstrated also that the matrix regularisation technique is suitable for deconvolution analysis of time-activity curves even when they are significantly contaminated by statistical noise. Calculation of the transfer function of liver perfusion and of its quantitative parameters seems thus to be a reliable method for non-invasive investigation of liver hemodynamics under physiological and pathological conditions.

  17. Theoretical considerations in measurement of time discrepancies between input and myocardial time-signal intensity curves in estimates of regional myocardial perfusion with first-pass contrast-enhanced MRI.

    Science.gov (United States)

    Natsume, Takahiro; Ishida, Masaki; Kitagawa, Kakuya; Nagata, Motonori; Sakuma, Hajime; Ichihara, Takashi

    2015-11-01

    The purpose of this study was to develop a method to determine time discrepancies between input and myocardial time-signal intensity (TSI) curves for accurate estimation of myocardial perfusion with first-pass contrast-enhanced MRI. Estimation of myocardial perfusion with contrast-enhanced MRI using kinetic models requires faithful recording of contrast content in the blood and myocardium. Typically, the arterial input function (AIF) is obtained by setting a region of interest in the left ventricular cavity. However, there is a small delay between the AIF and the myocardial curves, and such time discrepancies can lead to errors in flow estimation using Patlak plot analysis. In this study, the time discrepancies between the arterial TSI curve and the myocardial tissue TSI curve were estimated based on the compartment model. In the early phase after the arrival of the contrast agent in the myocardium, the relationship between rate constant K1 and the concentrations of Gd-DTPA contrast agent in the myocardium and arterial blood (LV blood) can be described by the equation K1={dCmyo(tpeak)/dt}/Ca(tpeak), where Cmyo(t) and Ca(t) are the relative concentrations of Gd-DTPA contrast agent in the myocardium and in the LV blood, respectively, and tpeak is the time corresponding to the peak of Ca(t). In the ideal case, the time corresponding to the maximum upslope of Cmyo(t), tmax, is equal to tpeak. In practice, however, there is a small difference in the arrival times of the contrast agent into the LV and into the myocardium. This difference was estimated to correspond to the difference between tpeak and tmax. The magnitudes of such time discrepancies and the effectiveness of the correction for these time discrepancies were measured in 18 subjects who underwent myocardial perfusion MRI under rest and stress conditions. The effects of the time discrepancies could be corrected effectively in the myocardial perfusion estimates.

  18. 64层VCT首过期灌注成像对肺部结节的诊断价值%First pass phase of perfusion imaging with 64-slice VCT in diagnosis of pulmonary nodules

    Institute of Scientific and Technical Information of China (English)

    舒圣捷; 黄晗; 刘白鹭; 王非; 赵雁鸣; 申秀芬

    2011-01-01

    Objective: To evaluate the diagnostic ability of first pass phase of perfusion imaging with 64-slice VCT between benign and malignant pulmonary nodules. Methods; A total of 108 patients with pulmonary nodules underwent perfusion scan with 64 slice spiral CT scanner. The parameters of CT perfusion. Including blood volume (BV), blood flow (BF). Mean transit time (MTT). Permeability surface (PS). And time-density curve (TDC). Were analyzed. The CT perfusion and enhanced parameters were compared with vascular endothelial growth factor (VEGF) expression by immunohis-tochemistry. Results: These parameter values in pulmonary malignancy nodules were highter than those in pulmonary benign nodules. The TDC appeared different for malignant and benign nodules. Conclusion: Perfusion CT can provide quantitative information about blood flow perfusion of nodules and it is meaningful to the diagnosis and differential diagnosis of pulmonary nodules.%目的:探讨首过期的64层VCT肺灌注成像对肺部结节的诊断意义.方法:对108例肺结节患者进行CT灌注扫描,测定肺结节的时间-密度曲线(TDC)、血容积(BV)、血流量(BF)、平均通过时间(MTT)和表面通透性(PS)的数值,并测量肺结节增强前的CT值、增强值和结节-动脉增强值之比(S/A).标定结节的血管内皮生长因子(VEGF),评价肺结节CT灌注和增强指数与VEGF表达的相关性.结果:肺癌的灌注指数高于肺良性结节.良、恶性结节的TDC形态不同.结论:CT肺灌注成像可定量的评价肺结节的血流灌注特点,对肺部结节有较大的诊断及鉴别诊断意义.

  19. First-pass and high-resolution steady-state magnetic resonance angiography of the peripheral arteries with gadobenate dimeglumine: an assessment of feasibility and diagnostic performance.

    Science.gov (United States)

    Anzidei, Michele; Napoli, Alessandro; Zaccagna, Fulvio; Cavallo Marincola, Beatrice; Zini, Chiara; Kirchin, Miles A; Catalano, Carlo; Passariello, Roberto

    2011-05-01

    To assess the feasibility of combined first-pass (FP) and steady-state (SS) contrast-enhanced magnetic resonance angiography (MRA) of the peripheral arteries with gadobenate dimeglumine (MultiHance) and to evaluate diagnostic performance relative to digital subtraction angiography (DSA). A total of 35 patients with symptomatic peripheral arterial occlusive disease (PAOD) underwent FP MRA (repetition time [TR]/echo time [TE]/flip angle [FA]/acquisition time [TA] = 3.5/1.2/30°/14s) at 1.5T after intravenous injection of 10 mL of gadobenate dimeglumine. Thereafter, SS imaging of the calf (TR/TE/FA/TA = 7.5/2.3/20°/40-130s) and femoropopliteal (TR/TE/FA/TA = 7.5/2.3/18°/130-240s) regions was performed after a second injection of 5 mL of gadobenate dimeglumine. All patients underwent conventional DSA. Three readers reviewed separate FP and FP+SS MRA datasets for image quality and presence/absence of clinically relevant PAOD. A fourth independent observer evaluated DSA images. The diagnostic performance (sensitivity, specificity, positive and negative predictive values) achieved with each dataset was determined and compared. Inter-reader agreement was assessed using kappa statistics. The image quality of 134 of 140 vascular regions was optimal or adequate on SS MRA. Inter-reader agreement was good to very good for assessments of FP (κ = 0.725) and combined FP+SS images (κ = 0.866). SS images improved diagnostic confidence in 34 (48.6%) femoropoliteal and 46 (65.7%) crural regions and altered final diagnosis in 8 (11.4%) and 10 (14.3%) regions, respectively. Global diagnostic accuracy increased from 92.9% on FP images to 95.9% on FP+SS images, with significant (P = 0.0384) improvement in the crural region. SS MRA of the peripheral arteries is feasible with gadobenate dimeglumine and potentially improves diagnostic performance in patients with symptomatic PAOD.

  20. 进展期非小细胞肺癌的首过法CT灌注可重复性研究%Advanced NSCLC First Pass Perfusion at 64-slice CT: Reproducibility of Volume-based Quantitative Measurement

    Institute of Scientific and Technical Information of China (English)

    单飞; 张志勇; 曾蒙苏; 胡洁; 白春学

    2010-01-01

    背景与目的 本研究旨在探讨进展期非小细胞肺癌(non-small cell lung cancer, NSCLC)首过法CT灌注(CT perfusion, CTP)的可重复性.方法 在本院行首过法CTP检查(8×5 mm层厚),且经病理证实的进展期NSCLC患者14例,肿瘤最大径≤3 cm及>3 cm各7例,均在24 h内行第二次CTP扫描.采用组内相关系数(intraclass correlationcoefficient, ICC)及Bland-Altman法评价CTP检查的可重复性.结果 两组进展期NSCLC的血流速度(blood flow, BF)、血容量(blood volume, BV)及表面通透性(permeability surface area product, PS)值的ICC均>0.75;对比剂的平均通过时间(mean transit time, MTT)的ICC均3 cm组的BF、BV、MTT及PS的RC及RC值95%变化区间依次为46%(-48%-45%)、30%(-33%-26%)、-59%(-54%-64%)、33%(-18%-48%).结论 去卷积法首过法CTP参数BF及BV可重复性较好,用于评价进展期NSCLC抗血管生成治疗疗效时,可根据肿瘤大小,应用不同的可重复性标准区别对待.

  1. Preliminary Study of Differentiating Benign and Malignant Pulmonary Nodules by 320-Slice CT with First-pass Perfusion Imaging (CT-PWI)%320排CT首过灌注成像鉴别良恶性肺结节初探

    Institute of Scientific and Technical Information of China (English)

    丁汉军; 杨蕊梦; 黄云海; 崔嵩; 曹丽妃

    2014-01-01

    Objective To explore the clinical application of 320-slice CT first-passperfusion imaging (CT-PWI) in differentiating benign and malignant pulmonary nodules. Methods 51 patients were diagnosed as pulmonary nodules,including inflammation (n=12), benign (n=5) and malignant(n=34)nodules. All the cases were performed thoracic dynamic volume CT examinations by 320-slice CT scanner. Perfusion parameters were acquired by perfusion software, and were statistically analyzed. Results Perfusion parameters such as pulmonary artery perfusion(PAP), bronchial artery perfusion(BAP), pulmonary artery perfusion index(PAPI) were acquired through pseudocolor maps. There were significant differences in the perfusion parameters among inflammatory, benign and malignant nodules. Conclusion Using 320-slice CT first-pass perfusion imaging(CT-PWI), it has advantages in differentiating benign and malignant pulmonary nodules, which possess practicability and superiority in clinic.%目的:探讨320排CT首过灌注成像鉴别良恶性肺结节的临床实用性。方法灌注成功并明确诊断的肺结节51例,包括12例肺炎性结节,5例肺良性结节,34例肺恶性结节,所有病例均进行320排CT肺部动态容积扫描,利用灌注软件获取肺结节兴趣区的灌注参数值,并进行统计学分析。结果通过肺结节灌注参数伪彩图获取病灶实质部分的肺动脉灌注量(PAP)、支气管动脉灌注量(BAP)、肺动脉灌注指数(PAPI)等参数值,肺炎性结节、肺良性结节、肺恶性结节三组的各项灌注参数均有显著性差异。结论320排CT首过灌注成像对良恶性肺结节的鉴别诊断有优势,具有临床实用性和优越性。

  2. EVALUATION OF PULMONARY HYPERTENSION AND STRATIFICATION OF RISK BY FIRST-PASS RADIONUCLIDE PULMONARY PERFUSION IMAGING IN PATIENTS WITH PULMONARY HYPERTENSION OF ACUTE PULMONARY EMBOLISM%应用首次通过法肺灌注显像对急性肺栓塞合并肺动脉高压的评价

    Institute of Scientific and Technical Information of China (English)

    王静; 李国华; 王雪梅

    2014-01-01

    Objective:The purpose of this study was to evaluate pulmonary hypertension( PH) and stratification of risk by first-pass radionuclide pulmonary perfusion imaging( FPPPI) in patients with PH of acute pulmonary embolism( APE) . Methods:twenty healthy volunteers(12 males,8 females,average age of 48. 47±13. 47)Twenty patients(11 males,9 females,average age of 49. 95±16. 13,accumulated from 2007-10~2009-02 ) with acute pulmonary embolism were included in our study. FPPPI were performed in all Subjects. Calculated by FPPPI lung equilibration time( LET) . Results:LET by FPPPI in healthy volunteers and APE patients were 12. 18±3. 28 sec and 32. 90±14. 29 sec,respectively. It is the significance between healthy volunteers and APE patients ( P<0 . 01 ) . Conclusion:FPPPI was a reliable,convenient andnon-invasivemethod in evaluating pulmonary hypertension in acute pulmonary embolism.%目的:应用首次通过法肺灌注显像( First-pass radionuclide pulmonary perfusion imaging,FPPPI)对急性肺栓塞( Acute pulmonary embolism APE)合并肺动脉高压( Pulmonary hypertension,PH)的评价。方法:20例健康自愿者,男12例,女8例,平均年龄为48.47依13.47岁(21~71岁),20例(2007-10~2009-02)临床诊断为急性肺栓塞病人,男11例,9例,平均年龄为49.95依16.13岁(23~82岁),所有受试者均行FPPPI检查,按FPPPI计算肺平衡时间(Lung equilibrium time LET)。结果:FPPPI法测定的肺平衡时间(LET),正常组LET 12.18依3.28 sec, APE组LET 32.90依14.29 sec 两组进行t检验,t=6.32,P<0.01,有统计学差别。结论:FPPPI是评价急性肺栓塞合并肺动脉高压的可靠、简便、无创性的方法。

  3. Regional Myocardial Blood Volume and Flow: First-Pass MR Imaging with Polylysine-Gd-DTPA

    Science.gov (United States)

    Wilke, Norbert; Kroll, Keith; Merkle, Hellmut; Wang, Ying; Ishibashi, Yukata; Xu, Ya; Zhang, Jiani; Jerosch-Herold, Michael; Mühler, Andreas; Stillman, Arthur E.; Bassingthwaighte, James B.; Bache, Robert; Ugurbil, Kamil

    2010-01-01

    The authors investigated the utility of an intravascular magnetic resonance (MR) contrast agent, poly-L-lysine-gadolinium diethylenetriaminepentaacetic acid (DTPA), for differentiating acutely ischemic from normally perfused myocardium with first-pass MR imaging. Hypoperfused regions, identified with microspheres, on the first-pass images displayed significantly decreased signal intensities compared with normally perfused myocardium (P < .0007). Estimates of regional myocardial blood content, obtained by measuring the ratio of areas under the signal intensity-versus-time curves in tissue regions and the left ventricular chamber, averaged 0.12 mL/g ± 0.04 (n = 35), compared with a value of 0.11 mL/g ± 0.05 measured with radiolabeled albumin in the same tissue regions. To obtain MR estimates of regional myocardial blood flow, in situ calibration curves were used to transform first-pass intensity-time curves into content-time curves for analysis with a multiple-pathway, axially distributed model. Flow estimates, obtained by automated parameter optimization, averaged 1.2 mL/min/g ± 0.5 [n = 29), compared with 1.3 mL/min/g ± 0.3 obtained with tracer microspheres in the same tissue specimens at the same time. The results represent a combination of T1-weighted first-pass imaging, intravascular relaxation agents, and a spatially distributed perfusion model to obtain absolute regional myocardial blood flow and volume. PMID:7766986

  4. 双能CT首过及延迟心肌灌注成像评价心肌活性:与99mT c-MIBI心肌灌注显影的对照研究%First-pass and Delay Myocardial Perfusion Imaging in Assessment of Myocardial Viability Using Dual-energy Computed Tomography:Comparison with99mTc-MIBI Imaging

    Institute of Scientific and Technical Information of China (English)

    李小荣; 欧陕兴; 钱民; 彭光明

    2015-01-01

    目的:通过对心肌梗死患者行双源CT首过及延迟增强双能量扫描,与99mTc-MIBI心肌显像结果进行对比研究,探讨双源CT首过及延迟心肌灌注成像在识别及定位存活心肌的诊断价值。方法28例心肌梗死患者接受双源首过及延迟(5min)心肌灌注扫描及99mTc-MIBI心肌灌注显影检查,观察双源CT心肌灌注碘图评价心肌灌注缺损,将双源CT首过及延迟扫描心肌灌注缺损与99mTc-MIBI的相应节段进行对照。结果28例受检者,共476个心肌节段,双源CT首过扫描心肌灌注共有371节段灌注减低及缺损,其中延迟扫描共156个节段表现为低灌注,215个节段表现为相对高灌注(延迟强化);99mTc-MIBI心肌灌注显影结果共有237心肌灌注减低及缺损;17个节段中,共13节段两者结果一致性好(Kappa值>0.75),其余4节段(第2、3、8、9节段)一致性一般(0.40<Kappa值<0.75);第8节段敏感度最高为(100%),第12节段特异度为最高为(100%),第12节段准确度最高为(92.85%)。结论双源CT首过及延迟心肌灌注成像评价心肌活性与99mTc-MIBI心肌灌注显影对比结果一致性良好,可较为准确地定位心肌梗死,并对心肌活性作出评估。%Objective To evaluate the feasibility and diagnostic accuracy of first-pass and delayed enhancement of dual-energy computed tomography(DECT) in myocardial perfusion imaging for detecting myocardial viability compared with99mTc-MIBI myocardial perfusion imaging.Methods Twenty-eight patients with coronary artery disease were detected by first-pass and delayed enhancement (5min) DECT and99mTc-MIBI PET respectively. A color-coded iodine map was used to evaluate the myocardial perfusion defects. Myocardial perfusion defects according to the first-pass and delayed enhancement were compared with99mTc-MIBI myocardial perfusion imaging on a segmental basis.Results A total of 476 myocardial segments of 28 patients were analyzed

  5. Dynamic perfusion CT: Optimizing the temporal resolution for the calculation of perfusion CT parameters in stroke patients

    Energy Technology Data Exchange (ETDEWEB)

    Kaemena, Andreas [Department of Radiology, Charite-Medical University Berlin, Augustenburger Platz 1, D-13353 Berlin (Germany)], E-mail: andreas.kaemena@charite.de; Streitparth, Florian; Grieser, Christian; Lehmkuhl, Lukas [Department of Radiology, Charite-Medical University Berlin, Augustenburger Platz 1, D-13353 Berlin (Germany); Jamil, Basil [Department of Radiotherapy, Charite-Medical University Berlin, Schumannstr. 20/21, D-10117 Berlin (Germany); Wojtal, Katarzyna; Ricke, Jens; Pech, Maciej [Department of Radiology, Charite-Medical University Berlin, Augustenburger Platz 1, D-13353 Berlin (Germany)

    2007-10-15

    Purpose: To assess the influence of different temporal sampling rates on the accuracy of the results from cerebral perfusion CTs in patients with an acute ischemic stroke. Material and methods: Thirty consecutive patients with acute stroke symptoms received a dynamic perfusion CT (LightSpeed 16, GE). Forty millilitres of iomeprol (Imeron 400) were administered at an injection rate of 4 ml/s. After a scan delay of 7 s, two adjacent 10 mm slices at 80 kV and 190 mA were acquired in a cine mode technique with a cine duration of 49 s. Parametric maps for the blood flow (BF), blood volume (BV) and mean transit time (MTT) were calculated for temporal sampling intervals of 0.5, 1, 2, 3 and 4 s using GE's Perfusion 3 software package. In addition to the quantitative ROI data analysis, a visual perfusion map analysis was performed. Results: The perfusion analysis proved to be technically feasible with all patients. The calculated perfusion values revealed significant differences with regard to the BF, BV and MTT, depending on the employed temporal resolution. The perfusion contrast between ischemic lesions and healthy brain tissue decreased continuously at the lower temporal resolutions. The visual analysis revealed that ischemic lesions were best depicted with sampling intervals of 0.5 and 1 s. Conclusion: We recommend a temporal scan resolution of two images per second for the best detection and depiction of ischemic areas.

  6. Colour atlas of first pass functional imaging of the heart

    Energy Technology Data Exchange (ETDEWEB)

    Schad, N.; Andrews, E.J.; Fleming, J.W.

    1985-01-01

    This book contains 21 chapters. Some of the titles are: Functional imaging; Fist pass radionuclide studies in evaluation of mitral valve replacement in chronic insufficiency using Bjork-Shiley tilting disc valves; First pass radionuclide studies in evaluation of left and right ventricular function in patients with bioprosthetic mitral valve replacement after 9-11 years; and First pass radionuclide studies in the evaluation of long term (up to about 15 years) follow up of aortic valve replacement using Starr-Edwards ball prosthesis.

  7. Peripheral Lung Adenocarcinoma versus Squamous Cell Carcinoma: Evaluation with First-pass Perfusion Imaging Using 64-detector Row CT%周围型肺腺癌与鳞癌64层螺旋CT首过时间灌注特征对比研究

    Institute of Scientific and Technical Information of China (English)

    李媛; 杨志刚; 陈天武; 余建群; 邓瑜萍; 李真林

    2009-01-01

    明确周围型肺腺癌与鳞癌首过时间CT灌注成像时间密度曲线及灌注值特征.对58例周围型肺腺癌和27例周围型肺鳞癌行64层螺旋CT首过时间灌注扫描,测定和评价病灶时间密度曲线(Time attenuation curve, TAC)、灌注值(perfusion)、强化峰值(PEI)、对比剂到达峰值时间(TTP)及血容量(BV)等灌注参数.周围型腺癌TACⅠ型占36.2%,Ⅱ型占63.8%;而周围型鳞癌TACⅠ型占22.2%,Ⅱ型占77.8%,两者构成比无显著差异(P>0.05).58例周围型腺癌首过时间CT perfusion值为63.2±45.4 ml·min-1·ml-1,PE值为60.2±46.6 Hu,TTP值为34.8±10.2 s,BV值为34.3±23.6 ml·100 g-1;27例周围型腺癌首过时间CT perfusion值为54.3±50.2 ml·min-1·ml-1,PE值为48.5±34.9 Hu,TTP值为36.1±11.2 s,BV值为27.6±21.7 ml·100g-1,两组间CT灌注值的差异均无统计学意义(P>0.05).表明周围型肺腺癌和鳞癌在TAC表现和CT灌注值均无显著差别.

  8. Contrast-enhanced CT- and MRI-based perfusion assessment for pulmonary diseases: basics and clinical applications.

    Science.gov (United States)

    Ohno, Yoshiharu; Koyama, Hisanobu; Lee, Ho Yun; Miura, Sachiko; Yoshikawa, Takeshi; Sugimura, Kazuro

    2016-01-01

    Assessment of regional pulmonary perfusion as well as nodule and tumor perfusions in various pulmonary diseases are currently performed by means of nuclear medicine studies requiring radioactive macroaggregates, dual-energy computed tomography (CT), and dynamic first-pass contrast-enhanced perfusion CT techniques and unenhanced and dynamic first-pass contrast enhanced perfusion magnetic resonance imaging (MRI), as well as time-resolved three-dimensional or four-dimensional contrast-enhanced magnetic resonance angiography (MRA). Perfusion scintigraphy, single-photon emission tomography (SPECT) and SPECT fused with CT have been established as clinically available scintigraphic methods; however, they are limited by perfusion information with poor spatial resolution and other shortcomings. Although positron emission tomography with 15O water can measure absolute pulmonary perfusion, it requires a cyclotron for generation of a tracer with an extremely short half-life (2 min), and can only be performed for academic purposes. Therefore, clinicians are concentrating their efforts on the application of CT-based and MRI-based quantitative and qualitative perfusion assessment to various pulmonary diseases. This review article covers 1) the basics of dual-energy CT and dynamic first-pass contrast-enhanced perfusion CT techniques, 2) the basics of time-resolved contrast-enhanced MRA and dynamic first-pass contrast-enhanced perfusion MRI, and 3) clinical applications of contrast-enhanced CT- and MRI-based perfusion assessment for patients with pulmonary nodule, lung cancer, and pulmonary vascular diseases. We believe that these new techniques can be useful in routine clinical practice for not only thoracic oncology patients, but also patients with different pulmonary vascular diseases.

  9. High-resolution myocardial perfusion mapping in small animals in vivo by spin-labeling gradient-echo imaging.

    Science.gov (United States)

    Kober, Frank; Iltis, Isabelle; Izquierdo, Marguerite; Desrois, Martine; Ibarrola, Danielle; Cozzone, Patrick J; Bernard, Monique

    2004-01-01

    An ECG and respiration-gated spin-labeling gradient-echo imaging technique is proposed for the quantitative and completely noninvasive measurement and mapping of myocardial perfusion in small animals in vivo. In contrast to snapshot FLASH imaging, the spatial resolution of the perfusion maps is not limited by the heart rate. A significant improvement in image quality is achieved by synchronizing the inversion pulse to the respiration movements of the animals, thereby allowing for spontaneous respiration. High-resolution myocardial perfusion maps (in-plane resolution=234 x 468 microm2) demonstrating the quality of the perfusion measurement were obtained at 4.7 T in a group of seven freely breathing Wistar-Kyoto rats under isoflurane anesthesia. The mean perfusion value (group average +/- SD) was 5.5 +/- 0.7 ml g(-1)min(-1). In four animals, myocardial perfusion was mapped and measured under cardiac dobutamine stress. Perfusion increased to 11.1 +/- 1.9 ml g(-1)min(-1). The proposed method is particularly useful for the study of small rodents at high fields.

  10. Clot resolution after 3 weeks of anticoagulant treatment of pulmonary embolism: Comparison of computed tomography and perfusion scintigraphy

    NARCIS (Netherlands)

    Van Es, J.; Douma, Renee; Kamphuisen, P.W.; Gerdes, V.E.A.; Verhamme, P.; Wells, P.S.; Bounameaux, H.; Lensing, A.W.A.; Büller, H.R.

    2013-01-01

    Introduction: Little is known about the natural history of clot resolution in the initial weeks of anticoagulant therapy in patients with acute pulmonary embolism (PE). Aim: To assess clot resolution of acute PE with either computed tomography pulmonary angiography (CT-scan) or perfusion

  11. Clot resolution after 3 weeks of anticoagulant treatment for pulmonary embolism : comparison of computed tomography and perfusion scintigraphy

    NARCIS (Netherlands)

    van Es, J.; Douma, R. A.; Kamphuisen, P. W.; Gerdes, V. E. A.; Verhamme, P.; Wells, P. S.; Bounameaux, H.; Lensing, A. W. A.; Bueller, H. R.

    2013-01-01

    Introduction Little is known about the natural history of clot resolution in the initial weeks of anticoagulant therapy in patients with acute pulmonary embolism (PE). Clot resolution of acute PE was assessed with either computed tomography pulmonary angiography scan (CT-scan) or perfusion scintigra

  12. Assessment of ventricular function with first-pass radionuclide angiography using technetium 99m hexakis-2-methoxyisobutylisonitrile: A European multicentre study

    Energy Technology Data Exchange (ETDEWEB)

    Bisi, G.; Sciagra, R. (Florence Univ. (Italy). Dipt. di Fisiopatologia Clinica); Buell, U. (Technische Hochschule Aachen (Germany, F.R.). Medizinische Fakultaet); Britton, K.E. (Saint Bartholomew' s Hospital, London (UK). Dept. of Nuclear Medicine); Eilles, C. (Luitpoldkrankenhaus, Wuerzburg (Germany, F.R.)); Eissner, D.; Hahn, K. (Mainz Univ. (Germany, F.R.). Klinikum); Hoeffken, H.; Joseph, K. (Marburg Univ. (Germany, F.R.). Klinikum); McKillop, J.H. (Royal Infirmary, Glasgow (UK). Dept. of Medicine); Larock, M.P.; Rigo, P. (Centre Hospitalier Universitaire Sart-Tilman, Tilman (Belgium). Service de Medecine Nucleaire); Mueller, S.P.; Reiners, C. (Essen Univ. (Gesamthochschule) (Germany, F.R.). Klinikum)

    1991-03-01

    In the context of a multicentre study on the use of technetium 99m hexakis-2-methoxyisobutylisonitrile ({sup 99m}Tc-Sestamibi), we evaluated the accuracy of the ventricular function assessed at rest by means of first-pass radionuclide angiocardiography acquired during the injection of the tracer for myocardial perfursion scintigraphy. The results were compared with first-pass studies performed using reference tracers sodium pertechnetate Tc 99m or technetium 99m diethylene triamine penta-acetic acid or with gated radionuclide angiocardiography. A total of 66 patients of the 105 enrolled in the study could be evaluated. The comparison of the first-pass studies was possible in 33 subjects with regard to the left ventricular ejection fraction, yielding r=0.909 (P<10{sup -6}), and in 22 cases with regard to the right ventricular ejection fraction, yielding r=0.712 (P<0.001). The comparison between the first-pass study using {sup 99m}Tc-Sestamibi and the equilibrium gated radionuclide angiocardiography was possible for the left ventricular ejection fraction in 26 cases, with r = 0.937 (P<10{sup -6}), and for the right ventricular ejection fraction in 15 subjects, with r=0.783 (P<0.001). In conclusion, the assessment of ventricular function performed by acquiring a first-pass radionuclide angiocardiograph during the injection of {sup 99m}Tc-Sestamibi for perfusion myocardial scintigraphy can be considered reliable and accurate, when compared with the usually employed techniques. This result confirms the feasibility of a combined evaluation of perfusion and function at rest and during stress testing, which represents one of the most interesting advantages offered by the use of {sup 99m}Tc-Sestamibi. (orig.).

  13. Extensive intestinal first-pass metabolism of arctigenin: evidenced by simultaneous monitoring of both parent drug and its major metabolites.

    Science.gov (United States)

    Gao, Qiong; Zhang, Yufeng; Wo, Siukwan; Zuo, Zhong

    2014-03-01

    The current study aims to investigate intestinal absorption and metabolism of arctigenin (AR) through simultaneous monitoring of AR and its major metabolites in rat plasma. An UPLC/MS/MS assay was developed with chromatographic separation of all analytes achieved by a C18 Column (3.9mm×150mm, 3.5μm) and a gradient elution with acetonitrile and 0.1% formic acid within 9min. Sample extraction with acetonitrile was optimized to achieve satisfactory recovery for both AR and its major metabolites. The lower limit of quantification (LLOQ) for all analytes was 25ng/ml. The intra-day and inter-day precision and accuracy of each analyte at LLOQ and three quality control (QC) concentrations (low, middle and high) in rat plasma was within 15.0% RSD and 15.0% bias. The extraction recoveries were within the range of 83.8-94.0% for all analytes. The developed and validated assay was then applied to the absorption study of AR in both Caco-2 cell monolayer model and in situ single-pass rat intestinal perfusion model. High absorption permeability of AR was demonstrated in both models with Papp of (1.76±0.48)×10(-5) (A→B) (Caco-2) and Pblood of (8.6±3.0)×10(-6)cm/s (intestinal perfusion). Extensive first-pass metabolism of AR to arctigenic acid (AA) and arctigenin-4'-O-glucuronide (AG) was identified in rat intestinal perfusion study with Cummins's extraction ratios of 0.458±0.012 and 0.085±0.013, respectively. The current assay method demonstrated to be a practical tool for pharmacokinetics investigation of AR with complicated metabolism pathways and multiple metabolites.

  14. Combined first pass and equilibrium radionuclide cardiographic determination of stroke volume for quantitation of valvular regurgitation

    DEFF Research Database (Denmark)

    Kelbaek, H; Aldershvile, J; Svendsen, Jesper Hastrup

    1988-01-01

    A new noninvasive procedure for quantitation of cardiac valve regurgitation was evaluated using a combination of first pass and gated equilibrium radionuclide cardiography in 38 subjects with and without cardiac valve disease. Left-sided cardiac catheterization was performed to determine the seve......A new noninvasive procedure for quantitation of cardiac valve regurgitation was evaluated using a combination of first pass and gated equilibrium radionuclide cardiography in 38 subjects with and without cardiac valve disease. Left-sided cardiac catheterization was performed to determine...... with mild mitral incompetence and 2+ aortic regurgitation, 37% in patients with moderate mitral incompetence and 3+ aortic regurgitation and 57% in patients with severe mitral incompetence and 4+ aortic regurgitation. These findings suggest that combined first pass and gated equilibrium radionuclide...

  15. First-pass metabolism of ethanol in human beings: effect of intravenous infusion of fructose

    DEFF Research Database (Denmark)

    Parlesak, Alexandr; Billinger, MH; Schäfer, C.

    2004-01-01

    Intravenous infusion of fructose has been shown to enhance reduced form of nicotinamide adenine dinucleotide reoxidation and, thereby, to enhance the metabolism of ethanol. In the current study, the effect of fructose infusion on first-pass metabolism of ethanol was studied in human volunteers....... A significantly higher first-pass metabolism of ethanol was obtained after administration of fructose in comparison with findings for control experiments with an equimolar dose of glucose. Because fructose is metabolized predominantly in the liver and can be presumed to have virtually no effects in the stomach......, results of the current study support the assumption that only a negligible part of first-pass metabolism of ethanol occurs in the stomach....

  16. Imaging diagnosis of right ventricular infarction and tricuspid regurgitation by radionuclide first pass method

    Energy Technology Data Exchange (ETDEWEB)

    Koito, Hitoshi; Iwasaka, Toshiji; Yoshioka, Hiroshi (Kansai Medical School, Moriguchi, Osaka (Japan))

    1983-07-01

    Radionuclide first pass findings of right ventricular infarction and tricuspid regurgitation are reported. Findings of right ventricular infarction are reduced wall motion and regional ejection fraction in the right ventricular inferior wall. Tricuspid regurgitation is suggested when the dilatation of right atrium and right ventricle are seen with regurgitant RI images through tricuspid valve. We can get regurgitant fraction from time-activity curve. Dynamic images are also useful for assessing quality of right ventricular infarction and tricuspid regurgitation. We conclude that radionuclide first pass method is useful to diagnose right ventricular infarction and to quantify tricuspid regurgitation.

  17. Intestinal first pass metabolism of midazolam in liver cirrhosis --effect of grapefruit juice

    DEFF Research Database (Denmark)

    Andersen, Vibeke; Pedersen, Natalie; Larsen, Niels-Erik

    2002-01-01

    Grapefruit juice inhibits CYP3A4 in the intestinal wall leading to a reduced intestinal first pass metabolism and thereby an increased oral bioavailability of certain drugs. For example, it has been shown that the oral bioavailability of midazolam, a CYP3A4 substrate, increased by 52% in healthy...

  18. Optimization of iterative reconstruction parameters with attenuation correction, scatter correction and resolution recovery in myocardial perfusion SPECT/CT

    OpenAIRE

    Okuda, Koichi; Nakajima, Kenichi; Yamada, Masato; Wakabayashi, Hiroshi; Ichikawa, Hajime; Arai, Hiroyuki; Matsuo, Shinro; Taki, Junichi; Hashimoto, Mitsumasa; Kinuya, Seigo

    2014-01-01

    Objective: The aim of this study was to characterize the optimal reconstruction parameters for ordered-subset expectation maximization (OSEM) with attenuation correction, scatter correction, and depth-dependent resolution recovery (OSEMACSCRR). We assessed the optimal parameters for OSEMACSCRR in an anthropomorphic torso phantom study, and evaluated the validity of the reconstruction parameters in the groups of normal volunteers and patients with abnormal perfusion. Methods: Images of the ant...

  19. Microfluidic Gut-liver chip for reproducing the first pass metabolism.

    Science.gov (United States)

    Choe, Aerim; Ha, Sang Keun; Choi, Inwook; Choi, Nakwon; Sung, Jong Hwan

    2017-03-01

    After oral intake of drugs, drugs go through the first pass metabolism in the gut and the liver, which greatly affects the final outcome of the drugs' efficacy and side effects. The first pass metabolism is a complex process involving the gut and the liver tissue, with transport and reaction occurring simultaneously at various locations, which makes it difficult to be reproduced in vitro with conventional cell culture systems. In an effort to tackle this challenge, here we have developed a microfluidic gut-liver chip that can reproduce the dynamics of the first pass metabolism. The microfluidic chip consists of two separate layers for gut epithelial cells (Caco-2) and the liver cells (HepG2), and is designed so that drugs go through a sequential absorption in the gut chamber and metabolic reaction in the liver chamber. We fabricated the chip and showed that the two different cell lines can be successfully co-cultured on chip. When the two cells are cultured on chip, changes in the physiological function of Caco-2 and HepG2 cells were noted. The cytochrome P450 metabolic activity of both cells were significantly enhanced, and the absorptive property of Caco-2 cells on chip also changed in response to the presence of flow. Finally, first pass metabolism of a flavonoid, apigenin, was evaluated as a model compound, and co-culture of gut and liver cells on chip resulted in a metabolic profile that is closer to the reported profile than a monoculture of gut cells. This microfluidic gut-liver chip can potentially be a useful platform to study the complex first pass metabolism of drugs in vitro.

  20. First-pass disposition of (-)-6-aminocarbovir in rats. I. Prodrug activation may be limited by access to enzyme.

    Science.gov (United States)

    Wen, Y; Remmel, R P; Zimmerman, C L

    1999-01-01

    Several in vitro and in situ approaches were used to determine the dominant presystemic activation site for (-)-6-aminocarbovir, (-)-carbocyclic 2',3'-didehydro-2', 3'-dideoxy-6-deoxy-6-aminoguanosine (6AC) conversion in rats. The in vitro disappearance half-lives (mean +/- S.D.) in the cytosolic fractions obtained from homogenates of the intestine, liver, and intestinal contents were 0.4 +/- 0.1 (n = 3), 12.2 +/- 1.1 (n = 3), and 15.5 (n = 1) min, respectively. An in situ vascularly perfused intestine-liver (IPIL) study was then carried out (n = 6) to determine the relative contribution of each presystemic organ to the overall first-pass extraction of 6AC. The 6AC extraction ratios in the intestine and liver in the IPIL were found to be 0.08 +/- 0.02 and 0.11 +/- 0.03, respectively. The intestinal extraction ratio was in dramatic contrast to the in vitro results. It was postulated that vascularly delivered 6AC had limited access to the metabolic site in the intestine. A theoretical analysis suggested that the extent of intestinal wall extraction of 6AC would be underestimated by the IPIL and should be determined after oral dosing. To compare intestinal extraction ratio in the IPIL with that after an oral administration, in situ intestinal lumen perfusions (n = 4) and intraportal infusions (n = 3) of 6AC were conducted in two groups of rats. The lumenally administered 6AC was extracted to a much greater extent by the intestine as compared with the IPIL, which presents 6AC to the intestine by the vascular route. The extraction ratio was found to be 0.54 +/- 0.06, which was significantly larger than that obtained in the IPIL.

  1. Measuring myocardial perfusion: the role of PET, MRI and CT.

    Science.gov (United States)

    Qayyum, A A; Kastrup, J

    2015-06-01

    Recently, focus has changed from anatomical assessment of coronary arteries towards functional testing to evaluate the effect of stenosis on the myocardium before intervention. Besides positron-emission tomography (PET), cardiac MRI (CMR), and cardiac CT are able to measure myocardial perfusion. Myocardial perfusion abnormalities are the first sign of the ischaemic cascade in the development of coronary artery disease (CAD). PET is considered the non-invasive clinical reference standard for absolute quantification of myocardial perfusion. The diagnostic and prognostic value of PET is well-known and is used in routine clinical practice. However, PET uses radioactive tracers and has a lower spatial resolution compared to CMR and CT. CMR and CT are emerging techniques in the field of myocardial perfusion imaging. CMR uses magnetic resonance to obtain images, whereas CT uses x-rays during first-pass of non-ionic and ionic contrast agents, respectively. Absolute quantification with CMR has yet to be established in routine clinical practice, while CT has yet to prove its diagnostic and prognostic value. The upcoming years may change the way we diagnose and treat patients suspected of having CAD with more precise methods for measuring myocardial perfusion. The aim of this comprehensive review is to discuss current and emerging imaging techniques used for myocardial perfusion imaging.

  2. Study of Stress and Strain Distributions of First Pass Conventional Spinning Under Different Roller-trace

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on simplified axisymmetrical forming model, a elasto-plastic FEM simulation system of multi-pass conventional spinning is developed. Taking the typical draw-spinning as the study object, and establishing reasonable mechanics model, research on the first pass of spinning process is carried out with FEM system developed. The distributions of the stress and strain are obtained by three types of roller-trace curves: straight line, involute curves and quadratic curves. The results are as follows: (1) The v...

  3. Intestinal first pass metabolism of midazolam in liver cirrhosis --effect of grapefruit juice

    DEFF Research Database (Denmark)

    Andersen, Vibeke; Pedersen, Natalie; Larsen, Niels-Erik

    2002-01-01

    AIMS: Grapefruit juice inhibits CYP3A4 in the intestinal wall leading to a reduced intestinal first pass metabolism and thereby an increased oral bioavailability of certain drugs. For example, it has been shown that the oral bioavailability of midazolam, a CYP3A4 substrate, increased by 52......, but these changes were not statistically significant, whereas C(max) of the metabolite decreased to 30% (14, 47%) (Ppass metabolism of midazolam. This is likely to occur...

  4. Intestinal first pass metabolism of midazolam in liver cirrhosis --effect of grapefruit juice

    DEFF Research Database (Denmark)

    Andersen, Vibeke; Pedersen, Natalie; Larsen, Niels-Erik

    2002-01-01

    Grapefruit juice inhibits CYP3A4 in the intestinal wall leading to a reduced intestinal first pass metabolism and thereby an increased oral bioavailability of certain drugs. For example, it has been shown that the oral bioavailability of midazolam, a CYP3A4 substrate, increased by 52% in healthy...... subjects after ingestion of grapefruit juice. However, this interaction has not been studied in patients with impaired liver function. Accordingly, the effect of grapefruit juice on the AUC of midazolam and the metabolite alpha-hydroxymidazolam was studied in patients with cirrhosis of the liver....

  5. Validity of blood flow measurement using 320 multi-detectors CT and first-pass distribution theory: a phantom study

    Science.gov (United States)

    Chen, Jun; Yu, Xuefang; Xu, Shaopeng; Zhou, Kenneth J.

    2015-03-01

    To evaluate the feasibility of measuring the myocardial blood flow using 320 row detector CT by first-pass technique. Heart was simulated with a container that was filled with pipeline of 3mm diameter; coronary artery was simulated with a pipeline of 2 cm diameter and connected with the simulated heart. The simulated coronary artery was connected with a big container with 1500 ml saline and 150ml contrast agent. One pump linking with simulated heart will withdraw with a speed of 10 ml/min, 15 ml/min, 20 ml/min, 25 ml/min and 30 ml/min. First CT scan starts after 30 s of pumpback with certain speed. The second CT scan starts 5 s after first CT scans. CT images processed as follows: The second CT scan images subtract first CT scan images, calculate the increase of CT value of simulated heart and the CT value of the unit volume of simulated coronary artery and then to calculate the total inflow of myocardial blood flow. CT myocardial blood flows were calculated as: 0.94 ml/s, 2.09 ml/s, 2.74 ml/s, 4.18 ml/s, 4.86 ml/s. The correlation coefficient is 0.994 and r2 = 0.97. The method of measuring the myocardial blood flow using 320 row detector CT by 2 scans is feasible. It is possible to develop a new method for quantitatively and functional assessment of myocardial perfusion blood flow with less radiation does.

  6. First pass cable artefact correction for cardiac C-arm CT imaging.

    Science.gov (United States)

    Haase, C; Schäfer, D; Kim, M; Chen, S J; Carroll, J D; Eshuis, P; Dössel, O; Grass, M

    2014-07-21

    Cardiac C-arm CT imaging delivers a tomographic region-of-interest reconstruction of the patient's heart during image guided catheter interventions. Due to the limited size of the flat detector a volume image is reconstructed, which is truncated in the cone-beam (along the patient axis) and the fan-beam (in the transaxial plane) direction. To practically address this local tomography problem correction methods, like projection extension, are available for first pass image reconstruction. For second pass correction methods, like metal artefact reduction, alternative correction schemes are required when the field of view is limited to a region-of-interest of the patient. In classical CT imaging metal artefacts are corrected by metal identification in a first volume reconstruction and generation of a corrected projection data set followed by a second reconstruction. This approach fails when the metal structures are located outside the reconstruction field of view. When a C-arm CT is performed during a cardiac intervention pacing leads and other cables are frequently positioned on the patients skin, which results in propagating streak artefacts in the reconstruction volume. A first pass approach to reduce this type of artefact is introduced and evaluated here. It makes use of the fact that the projected position of objects outside the reconstruction volume changes with the projection perspective. It is shown that projection based identification, tracking and removal of high contrast structures like cables, only detected in a subset of the projections, delivers a more consistent reconstruction volume with reduced artefact level. The method is quantitatively evaluated based on 50 simulations using cardiac CT data sets with variable cable positioning. These data sets are forward projected using a C-arm CT system geometry and generate artefacts comparable to those observed in clinical cardiac C-arm CT acquisitions. A C-arm CT simulation of every cardiac CT data set without

  7. High quality high spatial resolution functional classification in low dose dynamic CT perfusion using singular value decomposition (SVD) and k-means clustering

    Science.gov (United States)

    Pisana, Francesco; Henzler, Thomas; Schönberg, Stefan; Klotz, Ernst; Schmidt, Bernhard; Kachelrieß, Marc

    2017-03-01

    Dynamic CT perfusion acquisitions are intrinsically high-dose examinations, due to repeated scanning. To keep radiation dose under control, relatively noisy images are acquired. Noise is then further enhanced during the extraction of functional parameters from the post-processing of the time attenuation curves of the voxels (TACs) and normally some smoothing filter needs to be employed to better visualize any perfusion abnormality, but sacrificing spatial resolution. In this study we propose a new method to detect perfusion abnormalities keeping both high spatial resolution and high CNR. To do this we first perform the singular value decomposition (SVD) of the original noisy spatial temporal data matrix to extract basis functions of the TACs. Then we iteratively cluster the voxels based on a smoothed version of the three most significant singular vectors. Finally, we create high spatial resolution 3D volumes where to each voxel is assigned a distance from the centroid of each cluster, showing how functionally similar each voxel is compared to the others. The method was tested on three noisy clinical datasets: one brain perfusion case with an occlusion in the left internal carotid, one healthy brain perfusion case, and one liver case with an enhancing lesion. Our method successfully detected all perfusion abnormalities with higher spatial precision when compared to the functional maps obtained with a commercially available software. We conclude this method might be employed to have a rapid qualitative indication of functional abnormalities in low dose dynamic CT perfusion datasets. The method seems to be very robust with respect to both spatial and temporal noise and does not require any special a priori assumption. While being more robust respect to noise and with higher spatial resolution and CNR when compared to the functional maps, our method is not quantitative and a potential usage in clinical routine could be as a second reader to assist in the maps

  8. A direct aspiration first pass technique for retrieval of a detached coil.

    Science.gov (United States)

    Masahira, Noritaka; Ohta, Tsuyoshi; Fukui, Naoki; Yanagawa, Toshio; Kondou, Yuichirou; Morimoto, Masanori; Ueba, Tetsuya

    2016-11-01

    A 64-year-old man was referred to our hospital for treatment of a cerebral aneurysm that was incidentally found. The aneurysm was 7 mm in size and located on the left anterior communicating artery. Using a balloon assisted technique, we performed coil embolization. During the second coil insertion, the first coil was dislodged into the anterior communicating artery. We attempted coil retrieval using a snare, which was unsuccessful. We applied a direct aspiration first pass technique (ADAPT) and advanced a Penumbra 4MAX immediately proximal to the dislodged coil; the dislodged coil was then successfully retrieved. ADAPT is a simple procedure for retrieval of a detached coil, and it can be used as an alternative to the snare technique.

  9. C-arm cone beam CT perfusion imaging using the SMART-RECON algorithm to improve temporal sampling density and temporal resolution

    Science.gov (United States)

    Li, Yinsheng; Niu, Kai; Li, Ke; Schafer, Sebastian; Royalty, Kevin; Strother, Charles; Chen, Guang-Hong

    2016-03-01

    In this work, a newly developed reconstruction algorithm, Synchronized MultiArtifact Reduction with Tomographic RECONstruction (SMART-RECON), was applied to C-arm cone beam CT perfusion (CBCTP) imaging. This algorithm contains a special rank regularizer, designed to reduce limited-view artifacts associated with super- short scan reconstructions. As a result, high temporal sampling and temporal resolution image reconstructions were achieved using an interventional C-arm x-ray system. The algorithm was evaluated in terms of the fidelity of the dynamic contrast update curves and the accuracy of perfusion parameters through numerical simulation studies. Results shows that, not only were the dynamic curves accurately recovered (relative root mean square error ∈ [3%, 5%] compared with [13%, 22%] for FBP), but also the noise in the final perfusion maps was dramatically reduced. Compared with filtered backprojection, SMART-RECON generated CBCTP maps with much improved capability in differentiating lesions with perfusion deficits from the surrounding healthy brain tissues.

  10. Comparative analysis of iterative reconstruction algorithms with resolution recovery and new solid state cameras dedicated to myocardial perfusion imaging.

    Science.gov (United States)

    Brambilla, Marco; Lecchi, Michela; Matheoud, Roberta; Leva, Lucia; Lucignani, Giovanni; Marcassa, Claudio; Zoccarato, Orazio

    2017-03-23

    New technologies are available in myocardial perfusion imaging. They include new software that recovers image resolution and limits image noise, multifocal collimators and dedicated cardiac cameras in which solid-state detectors are used and all available detectors are constrained to imaging just the cardiac field of view. These innovations resulted in shortened study times or reduced administered activity to patients, while preserving image quality. Many single center and some multicenter studies have been published during the introduction of these innovations in the clinical practice. Most of these studies were lead in the framework of "agreement studies" between different methods of clinical measurement. They aimed to demonstrate that these new software/hardware solutions allow the acquisition of images with reduced acquisition time or administered activity with comparable results (as for image quality, image interpretation, perfusion defect quantification, left ventricular volumes and ejection fraction) to the standard-time or standard-dose SPECT acquired with a conventional gamma camera and reconstructed with the traditional FBP method, considered as the gold standard. The purpose of this review is to provide the reader with a comprehensive understanding of the pro and cons of the different approaches summarizing the achievements reached so far and the issues that need further investigations.

  11. Effects of glucose and ascorbic acid on absorption and first pass metabolism of isoniazid in rats.

    Science.gov (United States)

    Matsuki, Y; Katakuse, Y; Matsuura, H; Kiwada, H; Goromaru, T

    1991-02-01

    We examined the effect of glucose (Glu) and ascorbic acid (AA) on absorption and metabolism of isoniazid (INAH). After p.o. administration of INAH with or without Glu or AA, plasma concentration and urinary excretion of INAH and its metabolites, acetyl INAH (AcINAH), acetyl hydrazine (AcHy) and hydrazine (Hy), were determined by means of gas chromatography-mass spectrometry using stable isotope labeled compounds as internal standard. The combined administration of INAH with Glu or AA led to a significant decrease in the excretion of INAH and Hy, and a significant increase in the excretion of AcINAH and AcHy. The absorption amount of INAH was reduced to about one-half by the addition of Glu and the absorption rate of INAH markedly decreased in the case of co-administration of AA. Comparing the oral case with the results of i.v. administration, Glu and AA only affect the absorption process containing the first pass metabolism of INAH.

  12. 3D imaging of myocardial perfusion and coronary tree morphology from a single rotational angiogram

    Science.gov (United States)

    Lauritsch, Günter; Rohkohl, Christopher; Hornegger, Joachim; Sinha, Anil-Martin; Brachmann, Johannes; Rieber, Johannes; Rittger, Harald

    2011-03-01

    Diagnosis and treatment of coronary heart disease are performed in the catheter laboratory using an angiographic X-ray C-arm system. The morphology of the coronary tree and potentially ischemic lesions are determined in 2D projection views. The hemodynamic impact of the lesion would be valuable information for treatment decision. Using other modalities for functional imaging is disrupting the clinical workflow since the patient has to be transferred from the catheter laboratory to another scanner, and back to the catheter laboratory for performing the treatment. In this work a novel technology is used for simultaneous 3D imaging of first pass perfusion and the morphology of the coronary tree from a single rotational angiogram. A selective, single shot of contrast agent of less than 20ml directly into the coronaries is sufficient for a proper contrast resolution. Due to the long acquisition time cardiac motion has to be considered. A novel reconstruction technique for estimation and compensation of cardiac motion from the acquired projection data is used. The overlay of the 3D structure of the coronary tree and the perfusion image shows the correlation of myocardial areas and the associated coronary sections supporting that region. In a case example scar lesions caused by a former myocardial infarct are investigated. A first pass perfusion defect is found which is validated by a late enhancement magnetic resonance image. No ischemic defects are found. The non vital regions are still supported by the coronary vasculature.

  13. 4D micro-CT-based perfusion imaging in small animals

    Science.gov (United States)

    Badea, C. T.; Johnston, S. M.; Lin, M.; Hedlund, L. W.; Johnson, G. A.

    2009-02-01

    Quantitative in-vivo imaging of lung perfusion in rodents can provide critical information for preclinical studies. However, the combined challenges of high temporal and spatial resolution have made routine quantitative perfusion imaging difficult in rodents. We have recently developed a dual tube/detector micro-CT scanner that is well suited to capture first-pass kinetics of a bolus of contrast agent used to compute perfusion information. Our approach is based on the paradigm that the same time density curves can be reproduced in a number of consecutive, small (i.e. 50μL) injections of iodinated contrast agent at a series of different angles. This reproducibility is ensured by the high-level integration of the imaging components of our system, with a micro-injector, a mechanical ventilator, and monitoring applications. Sampling is controlled through a biological pulse sequence implemented in LabVIEW. Image reconstruction is based on a simultaneous algebraic reconstruction technique implemented on a GPU. The capabilities of 4D micro-CT imaging are demonstrated in studies on lung perfusion in rats. We report 4D micro-CT imaging in the rat lung with a heartbeat temporal resolution of 140 ms and reconstructed voxels of 88 μm. The approach can be readily extended to a wide range of important preclinical models, such as tumor perfusion and angiogenesis, and renal function.

  14. High-resolution wide-field imaging of perfused capillaries without the use of contrast agent

    Directory of Open Access Journals (Sweden)

    Nelson DA

    2011-08-01

    Full Text Available Darin A Nelson1, Zvia Burgansky-Eliash1,2, Hila Barash1, Anat Loewenstein3, Adiel Barak4, Elisha Bartov2, Tali Rock2, Amiram Grinvald51Optical Imaging Ltd, Rehovot, Israel; 2Department of Ophthalmology, Edith Wolfson Medical Center, Holon, Israel; 3Department of Ophthalmology, Tel Aviv Medical Center & Sackler Faculty of Medicine, Tel Aviv University, Israel; 4Department of Ophthalmology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel; 5Department of Neurobiology, The Weizmann Institute of Science, Rehovot, IsraelPurpose: Assessment of capillary abnormalities facilitates early diagnosis, treatment, and follow-up of common retinal pathologies. Injected contrast agents like fluorescein are widely used to image retinal capillaries, but this highly effective procedure has a few disadvantages, such as untoward side effects, inconvenience of injection, and brevity of the time window for clear visualization. The retinal function imager (RFI is a tool for monitoring retinal functions, such as blood velocity and oximetry, based on intrinsic signals. Here we describe the clinical use of hemoglobin in red blood cells (RBCs as an intrinsic motion-contrast agent in the generation of detailed noninvasive capillary-perfusion maps (nCPMs.Patients and methods: Multiple series of nCPM images were acquired from 130 patients with diabetic retinopathy, vein occlusion, central serous retinopathy, age-related macular degeneration, or metabolic syndrome, as well as from 37 healthy subjects. After registration, pixel value distribution parameters were analyzed to locate RBC motion.Results: The RFI yielded nCPMs demonstrating microvascular morphology including capillaries in exquisite detail. Maps from the same subject were highly reproducible in repeated measurements, in as much detail and often better than that revealed by the very best fluorescein angiography. In patients, neovascularization and capillary nonperfusion areas were clearly observed. Foveal avascular

  15. High temporal versus high spatial resolution in MR quantitative pulmonary perfusion imaging of two-year old children after congenital diaphragmatic hernia repair

    Energy Technology Data Exchange (ETDEWEB)

    Weidner, M.; Hagelstein, C.; Schoenberg, S.O.; Neff, K.W. [University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Institute of Clinical Radiology and Nuclear Medicine, Mannheim (Germany); Zoellner, F.G.; Schad, L.R. [Heidelberg University, Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Mannheim (Germany); Zahn, K. [University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Department of Pediatric Surgery, Mannheim (Germany); Schaible, T. [University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Department of Pediatrics, Mannheim (Germany)

    2014-10-15

    Congenital diaphragmatic hernia (CDH) leads to lung hypoplasia. Using dynamic contrast-enhanced (DCE) MR imaging, lung perfusion can be quantified. As MR perfusion values depend on temporal resolution, we compared two protocols to investigate whether ipsilateral lung perfusion is impaired after CDH, whether there are protocol-dependent differences, and which protocol is preferred. DCE-MRI was performed in 36 2-year old children after CDH on a 3 T MRI system; protocol A (n = 18) based on a high spatial (3.0 s; voxel: 1.25 mm{sup 3}) and protocol B (n = 18) on a high temporal resolution (1.5 s; voxel: 2 mm{sup 3}). Pulmonary blood flow (PBF), pulmonary blood volume (PBV), mean transit time (MTT), and peak-contrast-to-noise-ratio (PCNR) were quantified. PBF was reduced ipsilaterally, with ipsilateral PBF of 45 ± 26 ml/100 ml/min to contralateral PBF of 63 ± 28 ml/100 ml/min (p = 0.0016) for protocol A; and for protocol B, side differences were equivalent (ipsilateral PBF = 62 ± 24 vs. contralateral PBF = 85 ± 30 ml/100 ml/min; p = 0.0034). PCNR was higher for protocol B (30 ± 18 vs. 20 ± 9; p = 0.0294). Protocol B showed higher values of PBF in comparison to protocol A (p always <0.05). Ipsilateral lung perfusion is reduced in 2-year old children following CDH repair. Higher temporal resolution and increased voxel size show a gain in PCNR and lead to higher perfusion values. Protocol B is therefore preferred. (orig.)

  16. Pharmacokinetics and first-pass effects of epsilon-acetamidocaproic acid after administration of zinc acexamate in rats.

    Science.gov (United States)

    Choi, Y H; Lee, U; Suh, J H; Kim, Y G; Choi, E-Y; Oh, E; Lee, M G

    2010-07-01

    1. Zinc acexamate (ZAC) is ionized to zinc and epsilon-acetamidocaproic acid (AACA). Thus, the pharmacokinetics and tissue distribution of zinc and AACA after intravenous (50 mg kg(-1)) and oral (100 mg kg(-1)) administration of ZAC were evaluated in rats. Also the pharmacokinetics of AACA after intravenous (10, 20, 30, and 50 mg kg(-1)) and oral (20, 50, and 100 mg kg(-1)) administration of ZAC and the first-pass extractions of AACA at a ZAC dose of 20 mg kg(-1) were evaluated in rats. 2. After oral administration of ZAC (20 mg kg(-1)), approximately 0.408% of the oral dose was not absorbed, the F value was approximately 47.1%, and the hepatic and gastrointestinal (GI) first-pass extractions of AACA were approximately 8.50% and 46.4% of the oral dose, respectively. The incomplete F value of AACA was mainly due to the considerable GI first-pass extraction in rats. 3. Affinity of rat tissues to zinc and AACA was low-the tissue-to-plasma (T/P) ratios were less than unity. The equilibrium plasma-to-blood cells partition ratios of AACA were independent of initial blood ZAC concentrations of 1, 5, and 10 microg ml(-1)-the mean values were 0.481, 0.490, and 0.499, respectively. The bound fractions of zinc and AACA to rat plasma were 96.6% and 39.0%, respectively.

  17. Perfusion analysis using a wide coverage flat-panel volume CT: feasibility study

    Science.gov (United States)

    Grasruck, M.; Gupta, R.; Reichardt, B.; Klotz, E.; Schmidt, B.; Flohr, T.

    2007-03-01

    We developed a Flat-panel detector based Volume CT (VCT) prototype scanner with large z-coverage. In that prototype scanner a Varian 4030CB a-Si flat-panel detector was mounted in a multi slice CT-gantry (Siemens Medical Solutions) which provides a 25 cm field of view with 18 cm z-coverage at isocenter. The large volume covered in one rotation can be used for visualization of complete organs of small animals, e.g. rabbits. By implementing a mode with continuous scanning, we are able to reconstruct the complete volume at any point in time during the propagation of a contrast bolus. Multiple volumetric reconstructions over time elucidate the first pass dynamics of a bolus of contrast resulting in 4-D angiography and potentially allowing whole organ perfusion analysis. We studied to which extent pixel based permeability and blood volume calculation with a modified Patlak approach was possible. Experimental validation was performed by imaging evolution of contrast bolus in New Zealand rabbits. Despite the short circulation time of a rabbit, the temporal resolution was sufficient to visually resolve various phases of the first pass of the contrast bolus. Perfusion imaging required substantial spatial smoothing but allowed a qualitative discrimination of different types of parenchyma in brain and liver. If a true quantitative analysis is possible, requires further studies.

  18. An integrated environmental perfusion chamber and heating system for long-term, high resolution imaging of living cells.

    Science.gov (United States)

    Hing, W A; Poole, C A; Jensen, C G; Watson, M

    2000-08-01

    This communication presents the design and application of an integrated environmental perfusion chamber and stage heating blanket suitable for time-lapse video microscopy of living cells. The system consists of two independently regulated components: a perfusion chamber suitable for the maintenance of cell viability and the variable delivery of environmental factors, and a separate heating blanket to control the temperature of the microscope stage and limit thermal conduction from the perfusion chamber. Two contrasting experiments are presented to demonstrate the versatility of the system. One long-term sequence illustrates the behaviour of cells exposed to ceramic fibres. The other shows the shrinking response of cultured articular cartilage chondrons under dynamic hyper-osmotic conditions designed to simulate joint loading. The chamber is simple in design, economical to produce and permits long-term examination of dynamic cellular behaviour while satisfying the fundamental requirements for the maintenance of environmental factors that influence cell viability.

  19. Comparison of quantitative myocardial perfusion imaging CT to fluorescent microsphere-based flow from high-resolution cryo-images

    Science.gov (United States)

    Eck, Brendan L.; Fahmi, Rachid; Levi, Jacob; Fares, Anas; Wu, Hao; Li, Yuemeng; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    Myocardial perfusion imaging using CT (MPI-CT) has the potential to provide quantitative measures of myocardial blood flow (MBF) which can aid the diagnosis of coronary artery disease. We evaluated the quantitative accuracy of MPI-CT in a porcine model of balloon-induced LAD coronary artery ischemia guided by fractional flow reserve (FFR). We quantified MBF at baseline (FFR=1.0) and under moderate ischemia (FFR=0.7) using MPI-CT and compared to fluorescent microsphere-based MBF from high-resolution cryo-images. Dynamic, contrast-enhanced CT images were obtained using a spectral detector CT (Philips Healthcare). Projection-based mono-energetic images were reconstructed and processed to obtain MBF. Three MBF quantification approaches were evaluated: singular value decomposition (SVD) with fixed Tikhonov regularization (ThSVD), SVD with regularization determined by the L-Curve criterion (LSVD), and Johnson-Wilson parameter estimation (JW). The three approaches over-estimated MBF compared to cryo-images. JW produced the most accurate MBF, with average error 33.3+/-19.2mL/min/100g, whereas LSVD and ThSVD had greater over-estimation, 59.5+/-28.3mL/min/100g and 78.3+/-25.6 mL/min/100g, respectively. Relative blood flow as assessed by a flow ratio of LAD-to-remote myocardium was strongly correlated between JW and cryo-imaging, with R2=0.97, compared to R2=0.88 and 0.78 for LSVD and ThSVD, respectively. We assessed tissue impulse response functions (IRFs) from each approach for sources of error. While JW was constrained to physiologic solutions, both LSVD and ThSVD produced IRFs with non-physiologic properties due to noise. The L-curve provided noise-adaptive regularization but did not eliminate non-physiologic IRF properties or optimize for MBF accuracy. These findings suggest that model-based MPI-CT approaches may be more appropriate for quantitative MBF estimation and that cryo-imaging can support the development of MPI-CT by providing spatial distributions of MBF.

  20. Learning first-pass structural attachment preferences with dynamic grammars and recursive neural networks.

    Science.gov (United States)

    Sturt, Patrick; Costa, Fabrizio; Lombardo, Vincenzo; Frasconi, Paolo

    2003-06-01

    One of the central problems in the study of human language processing is ambiguity resolution: how do people resolve the extremely pervasive ambiguity of the language they encounter? One possible answer to this question is suggested by experience-based models, which claim that people typically resolve ambiguities in a way which has been successful in the past. In order to determine the course of action that has been "successful in the past" when faced with some ambiguity, it is necessary to generalize over past experience. In this paper, we will present a computational experience-based model, which learns to generalize over linguistic experience from exposure to syntactic structures in a corpus. The model is a hybrid system, which uses symbolic grammars to build and represent syntactic structures, and neural networks to rank these structures on the basis of its experience. We use a dynamic grammar, which provides a very tight correspondence between grammatical derivations and incremental processing, and recursive neural networks, which are able to deal with the complex hierarchical structures produced by the grammar. We demonstrate that the model reproduces a number of the structural preferences found in the experimental psycholinguistics literature, and also performs well on unrestricted text.

  1. High resolution three-dimensional cardiac perfusion imaging using compartment-based k-t principal component analysis

    DEFF Research Database (Denmark)

    Vitanis, Viton; Manka, Robert; Giese, Daniel;

    2011-01-01

    -t principal component analysis reconstructions. Comparison of the two methods based on rest and stress three-dimensional perfusion data acquired with 2.3 × 2.3 × 10 mm(3) during a 225 msec acquisition window in patients confirms the findings and demonstrates the potential of compartment-based k-t principal...... permits three-dimensional perfusion imaging at 10-fold nominal acceleration. Using numerical simulations, it is shown that the compartment-based method results in accurate representations of dynamic signal intensity changes with significant improvements of temporal fidelity in comparison to conventional k...

  2. First-Pass Contrast-Enhanced MR Angiography in Evaluation of Treated Spinal Arteriovenous Fistulas: Is Catheter Angiography Necessary?

    Science.gov (United States)

    Mathur, S; Symons, S P; Huynh, T J; Marotta, T R; Aviv, R I; Bharatha, A

    2017-01-01

    Catheter angiography is typically used for follow-up of treated spinal AVFs. The purpose of this study was to determine the diagnostic performance and utility of first-pass contrast-enhanced MRA in the posttreatment evaluation of spinal AVFs compared with DSA. A retrospective review was performed of all patients at our tertiary referral hospital (from January 2000 to April 2015) who underwent spine MR imaging, first-pass contrast-enhanced MRA, and DSA after surgical and/or endovascular treatment of a spinal AVF. Presence of recurrent or residual fistula on MRA, including vertebral level of the recurrent/residual fistula, was evaluated by 2 experienced neuroradiologists blinded to DSA findings. Posttreatment conventional MR imaging findings were also evaluated, including presence of intramedullary T2 hyperintensity, perimedullary serpentine flow voids, and cord enhancement. The performance of MRA and MR imaging findings for diagnosis of recurrent/residual fistula was determined by using DSA as the criterion standard. In total, 28 posttreatment paired MR imaging/MRA and DSA studies were evaluated in 22 patients with prior spinal AVF and 1 patient with intracranial AVF with prior cervical perimedullary venous drainage. Six image sets of 5 patients demonstrated recurrent/residual disease at DSA. MRA correctly identified all cases with recurrent/residual disease with 1 false-positive (sensitivity, 100%; specificity 95%; P MR imaging parameters were not significantly associated with recurrent/residual spinal AVF. First-pass MRA demonstrates high sensitivity and specificity for identifying recurrent/residual spinal AVFs and may potentially substitute for DSA in the posttreatment follow-up of patients with spinal AVFs. © 2017 by American Journal of Neuroradiology.

  3. First-Pass Meconium Samples from Healthy Term Vaginally-Delivered Neonates: An Analysis of the Microbiota.

    Directory of Open Access Journals (Sweden)

    Richard Hansen

    Full Text Available Considerable effort has been made to categorise the bacterial composition of the human gut and correlate findings with gastrointestinal disease. The infant gut has long been considered sterile at birth followed by rapid colonisation; however, this view has recently been challenged. We examined first-pass meconium from healthy term infants to confirm or refute sterility.Healthy mothers were approached following vaginal delivery. First-pass meconium stools within 24 hours of delivery were obtained from healthy, breastfed infants with tight inclusion/exclusion criteria including rejecting any known antibiotic exposure - mother within 7 days preceding delivery or infant after birth. Stools were processed in triplicate for fluorescent in-situ hybridisation (FISH with 16S rRNA-targeted probes including Bifidobacterium; Bacteroides-Prevotella; Lactobacillaceae/Enterococcaceae; Enterobacteriaceae; Streptococcaceae; Staphylococcaceae and Enterococcaceae. Absolute counts of all bacteria and proportional identification of each bacterial group were calculated. Confirmation of bacterial presence by PCR was undertaken on FISH-positive samples.The mothers of 31 newborn infants were recruited, 15 met inclusion/exclusion criteria and provided a sample within 24 hours of birth, processed in the lab within 4 hours. All babies were 37-40 weeks gestation. 8/15 were male, mean birth weight was 3.4 kg and mean maternal age was 32 years. Meconium samples from 10/15 (66% infants had evidence of bacteria based on FISH analysis. Of these, PCR was positive in only 1. Positive FISH counts ranged from 2.2-41.8 x 10(4 cells/g with a mean of 15.4 x 10(4 cells/g. (The limit of detection for automated counting is 10(6 cells/g. Cell counts were too low to allow formal diversity analysis. Amplification by PCR was not possible despite positive spiked samples demonstrating the feasibility of reaction. One baby was dominated by Enterobacteriaceae. The others contained 2-5 genera

  4. Phase changes caused by hyperventilation stress in spastic angina pectoris analyzed by first-pass radionuclide ventriculography

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jin; Takeda, Tohoru; Ajisaka, Ryuichi; Masuoka, Takeshi; Watanabe, Sigeyuki; Sato, Motohiro; Itai, Yuji [Tsukuba Univ., Ibaraki (Japan). Inst. of Clinical Medicine; Toyama, Hinako; Ishikawa, Nobuyoshi

    1999-02-01

    To understand the effect of hyperventilation (HV) stress in patients with spastic angina, left ventricular (LV) contraction was analyzed by quantitative phase analysis. The study was performed on 36 patients with spastic angina pectoris, including vasospastic angina pectoris (VspAP: 16 patients) and variant angina pectoris (VAP: 20 patients). First-pass radionuclide ventriculography (first-pass RNV) was performed at rest and after HV stress, and standard deviation of the LV phase distribution (SD) was analyzed. The SD was lower in patients with VspAP than in VAP(12.8{+-}1.4 degrees vs. 14.6{+-}2.2 degrees, p<0.005) at rest. After HV stress, the SD (HVSD) tended to increase in VspAP patients (62.5%), whereas the SD decreased in VAP patients (70%). Due to HV stress, the percentage change in SD (%SD) in VspAP patients was 8.9{+-}23.7% whereas that in VAP patients was -9.1{+-}17.3% (p<0.01). Moreover, phase histograms were divided into HVSD increase and HVSD decrease groups. The HVSD increase group had a decrease of HVEF, but the HVSD decrease group tended to have more decreased HVEF than the HVSD increase group. These results indicate that spastic angina pectoris patients show various responses to HV stress. The HVSD increase group might have additional myocardial ischemia due to regional coronary spasm. In contrast, in the HVSD decrease group severe LV dysfunction or diffuse wall motion abnormality might have been generated, and this caused a reduction in the SD value. Phase analysis would therefore add new information regarding electrocardiographically silent myocardial ischemia due to coronary spasm, and HV stress might increase sensitivity for the detection of abnormalities in quantitative phase analysis, especially in VspAP patients. (author)

  5. Comparison of first pass bolus AIFs extracted from sequential {sup 18}F-FDG PET and DSC-MRI of mice

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Eleanor, E-mail: ee244@cam.ac.uk [Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0QQ (United Kingdom); Sawiak, Stephen J. [Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0QQ (United Kingdom); Behavioural and Clinical Neuroscience Institute, Department of Experimental Psychology, University of Cambridge, Cambridge, CB2 3EB (United Kingdom); Ward, Alexander O.; Buonincontri, Guido; Hawkes, Robert C.; Adrian Carpenter, T. [Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0QQ (United Kingdom)

    2014-01-11

    Accurate kinetic modelling of in vivo physiological function using positron emission tomography (PET) requires determination of the tracer time–activity curve in plasma, known as the arterial input function (AIF). The AIF is usually determined by invasive blood sampling methods, which are prohibitive in murine studies due to low total blood volumes. Extracting AIFs from PET images is also challenging due to large partial volume effects (PVE). We hypothesise that in combined PET with magnetic resonance imaging (PET/MR), a co-injected bolus of MR contrast agent and PET ligand can be tracked using fast MR acquisitions. This protocol would allow extraction of a MR AIF from MR contrast agent concentration–time curves, at higher spatial and temporal resolution than an image-derived PET AIF. A conversion factor could then be applied to the MR AIF for use in PET kinetic analysis. This work has compared AIFs obtained from sequential DSC-MRI and PET with separate injections of gadolinium contrast agent and {sup 18}F-FDG respectively to ascertain the technique′s validity. An automated voxel selection algorithm was employed to improve MR AIF reproducibility. We found that MR and PET AIFs displayed similar character in the first pass, confirmed by gamma variate fits (p<0.02). MR AIFs displayed reduced PVE compared to PET AIFs, indicating their potential use in PET/MR studies.

  6. Influence of blood viscosity on circulatory parameters determined by first-pass radionuclide angiocardiography in cor pulmonale

    Energy Technology Data Exchange (ETDEWEB)

    Zambo, K. [Dept. of Nuclear Medicine, Pecs (Hungary); Toth, K. [Dept. of Medicine, Div. of Cardiology Univ. Medical School, Pecs (Hungary)

    1993-12-01

    First-pass radionuclide angiocardiography (FPRNA) with {sup 99m}Tc-albumin was performed in 19 patients with cor pulmonale. Pulmonary circulation time (PCT), mean transit time (MTT), pulmonary stagnation index (PSI) were calculated from the time-activity curves for the estimation of cardiopulmonary circulation. Whole blood viscosity (WBV), plasma viscosity (PV) and hematocrit (HTC) were also measured on the same day. Significant prolongation of all parameters was observed (WBW: 5,04{+-}1.19 mPAS; PV: 1,36{+-}0,17 mPAS; HTC: 47,6{+-}2,37%; PCT: 7,10{+-}2,15 s; MTT: 9,33{+-}4,11 s; PSI: 1,30{+-}0,37) in patients with cor pulmonale. Significant positive correlations were found between PCT and WBV (r=0,552; 0,001First-Pass Untersuchung (FPRNA) mit {sup 99m}Tc-Albumin wurde bei 19 Patienten mit Cor pulmonale durchgefuehrt. Pulmonale Zirkulationszeit (PCT), `mean transit` Zeit (MTT), pulmonaler Rest Index (PSI) wurden ermittelt aus den Zeit-Aktivitaetskurven zur Einschaetzung des kardiopulmonalen Durchflusses. Vollblut-Viskositaet (WBV), Plasma-Viskositaet (PV) und Haematokrit (HTC) wurden am selben Tage gemessen. Bezeichnend fuer Patienten mit Cor pulmonale war eine typische Vergroesserung aller Parameter (WBV: 5,04{+-}1,19 mPAS; PV: 1,36{+-}0,17 mPAS; HTC: 47,6{+-}2,37%; PCT: 7,10{+-}2,15 s; MTT: 9,33{+-}4,11 s; PSI: 1,30{+-}0,37). Verwertbare Korrelationen wurden zwischen PCT und WBV (r=0,552; 0,001

  7. Gadofosveset-enhanced MR angiography of carotid arteries: does steady-state imaging improve accuracy of first-pass imaging? Comparison with selective digital subtraction angiography.

    Science.gov (United States)

    Anzidei, Michele; Napoli, Alessandro; Marincola, Beatrice Cavallo; Nofroni, Italo; Geiger, Daniel; Zaccagna, Fulvio; Catalano, Carlo; Passariello, Roberto

    2009-05-01

    To evaluate the diagnostic accuracy of gadofosveset-enhanced magnetic resonance (MR) angiography in the assessment of carotid artery stenosis, with digital subtraction angiography (DSA) as the reference standard, and to determine the value of reading first-pass, steady-state, and "combined" (first-pass plus steady-state) MR angiograms. This study was approved by the local ethics committee, and all subjects gave written informed consent. MR angiography and DSA were performed in 84 patients (56 men, 28 women; age range, 61-76 years) with carotid artery stenosis at Doppler ultrasonography. Three readers reviewed the first-pass, steady-state, and combined MR data sets, and one independent observer evaluated the DSA images to assess stenosis degree, plaque morphology and ulceration, stenosis length, and tandem lesions. Interobserver agreement regarding MR angiographic findings was analyzed by using intraclass correlation and Cohen kappa coefficients. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated by using the McNemar test to determine possible significant differences (P < .05). Interobserver agreement regarding all MR angiogram readings was substantial. For grading stenosis, sensitivity, specificity, PPV, and NPV were, respectively, 90%, 92%, 91%, and 91% for first-pass imaging; 95% each for steady-state imaging; and 96%, 99%, 99%, and 97% for combined imaging. For evaluation of plaque morphology, respective values were 84%, 86%, 88%, and 82% for first-pass imaging; 98%, 97%, 98%, and 97% for steady-state imaging; and 98%, 100%, 100%, and 97% for combined imaging. Differences between the first-pass, steady-state, and combined image readings for assessment of stenosis degree and plaque morphology were significant (P < .001). Gadofosveset-enhanced MR angiography is a promising technique for imaging carotid artery stenosis. Steady-state image reading is superior to first-pass image reading, but the combined

  8. High-temporospatial-resolution dynamic contrast-enhanced (DCE) wrist MRI with variable-density pseudo-random circular Cartesian undersampling (CIRCUS) acquisition: evaluation of perfusion in rheumatoid arthritis patients.

    Science.gov (United States)

    Liu, Jing; Pedoia, Valentina; Heilmeier, Ursula; Ku, Eric; Su, Favian; Khanna, Sameer; Imboden, John; Graf, Jonathan; Link, Thomas; Li, Xiaojuan

    2016-01-01

    This study is to evaluate highly accelerated three-dimensional (3D) dynamic contrast-enhanced (DCE) wrist MRI for assessment of perfusion in rheumatoid arthritis (RA) patients. A pseudo-random variable-density undersampling strategy, circular Cartesian undersampling (CIRCUS), was combined with k-t SPARSE-SENSE reconstruction to achieve a highly accelerated 3D DCE wrist MRI. Two healthy volunteers and 10 RA patients were studied. Two patients were on methotrexate (MTX) only (Group I) and the other eight were treated with a combination therapy of MTX and anti-tumor necrosis factor (TNF) therapy (Group II). Patients were scanned at baseline and 3 month follow-up. DCE MR images were used to evaluate perfusion in synovitis and bone marrow edema pattern in the RA wrist joints. A series of perfusion parameters was derived and compared with clinical disease activity scores of 28 joints (DAS28). 3D DCE wrist MR images were obtained with a spatial resolution of 0.3 × 0.3 × 1.5 mm(3) and temporal resolution of 5 s (with an acceleration factor of 20). The derived perfusion parameters, most notably transition time (dT) of synovitis, showed significant negative correlations with DAS28-ESR (r = -0.80, p perfusion in RA joints, showing promise as a potential tool for evaluating treatment responses.

  9. Pulmonary functional MRI:an animal model study of oxygen-enhanced ventilation combined with Gd-DTPA-enhanced perfusion

    Institute of Scientific and Technical Information of China (English)

    杨健; 万明习; 郭佑民

    2004-01-01

    Background The assessment of regional pulmonary ventilation and perfusion is essential for the evaluation of a variety of lung disorders. Pulmonary ventilation MRI using inhaled oxygen as a contrast medium can be obtained with a clinical MR scanner, without additional equipment, and has been demonstrated to be a feasible means of assessing ventilation in animal models and some clinical patients. However, few studies have reported on MR ventilation-perfusion imaging. In this study, we evaluated the usefulness of oxygen-enhanced ventilation in combination with first-pass Gd-DTPA-enhanced perfusion MRI in a canine model of pulmonary embolism and airway obstruction.Methods Peripheral pulmonary embolisms were produced in eight dogs by intravenous injection of gelfoam strips at the pulmonary segmental arterial level, and airway obstructions were created in five of the dogs by inserting a self-designed balloon catheter into a secondary bronchus. Oxygen-enhanced MR ventilation images were produced by subtracting images from before and after inhalation of pure oxygen. Pulmonary perfusion MR images were acquired with a dynamic three-dimensional fast gradient-echo sequence. MR ventilation and perfusion images were read and contrasted with results from general examinations of pathological anatomy, ventilation-perfusion scintigraphy, and pulmonary angiography. Results Regions identified as having airway obstructions matched using both MR ventilation and perfusion imaging, but regions of pulmonary embolisms were mismatched. The area of airway obstruction defects was smaller using MR ventilation imagery than that using ventilation scintigraphy. Abnormal perfusion regions due to pulmonary embolisms were divided into defective regions and reduced regions based on the time course of signal intensity changes. In the diagnosis of pulmonary embolisms with the technique of ventilation and perfusion MRI, sensitivity and specificity were 75.0% and 98.1%, respectively, and the diagnostic

  10. Rest perfusion abnormalities in hypertrophic cardiomyopathy: correlation with myocardial fibrosis and risk factors for sudden cardiac death.

    Science.gov (United States)

    Chiribiri, A; Leuzzi, S; Conte, M R; Bongioanni, S; Bratis, K; Olivotti, L; De Rosa, C; Lardone, E; Di Donna, P; Villa, A D M; Cesarani, F; Nagel, E; Gaita, F; Bonamini, R

    2015-05-01

    To measure the prevalence of abnormal rest perfusion in a population of consecutive patients with known hypertrophic cardiomyopathy (HCM) referred for cardiovascular MRI (CMR), and to assess any associations between abnormal rest perfusion and the presence, pattern, and severity of myocardial scar and the presence of risk factors for sudden death. Eighty consecutive patients with known HCM referred for CMR underwent functional imaging, rest first-pass perfusion, and late gadolinium enhancement (LGE). Thirty percent of the patients had abnormal rest perfusion, all of them corresponding to areas of mid-myocardial LGE and to a higher degree of segmental hypertrophy. Rest perfusion abnormalities correlated with more extensive and confluent LGE. The subgroup of patients with myocardial fibrosis and rest perfusion abnormalities (fibrosis+/perfusion+) had more than twice the incidence of episodes of non-sustained ventricular tachycardia on Holter monitoring in comparison to patients with myocardial fibrosis and normal rest perfusion (fibrosis+/perfusion-) and patients with no fibrosis and normal rest perfusion (fibrosis-/perfusion-). First-pass perfusion CMR identifies abnormal rest perfusion in a significant proportion of patients with HCM. These abnormalities are associated with the presence and distribution of myocardial scar and the degree of hypertrophy. Rest perfusion abnormalities identify patients with increased incidence of episodes of non-sustained ventricular tachycardia on Holter monitoring, independently from the presence of myocardial fibrosis. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  11. Inhibition of human alcohol and aldehyde dehydrogenases by acetaminophen: Assessment of the effects on first-pass metabolism of ethanol.

    Science.gov (United States)

    Lee, Yung-Pin; Liao, Jian-Tong; Cheng, Ya-Wen; Wu, Ting-Lun; Lee, Shou-Lun; Liu, Jong-Kang; Yin, Shih-Jiun

    2013-11-01

    Acetaminophen is one of the most widely used over-the-counter analgesic, antipyretic medications. Use of acetaminophen and alcohol are commonly associated. Previous studies showed that acetaminophen might affect bioavailability of ethanol by inhibiting gastric alcohol dehydrogenase (ADH). However, potential inhibitions by acetaminophen of first-pass metabolism (FPM) of ethanol, catalyzed by the human ADH family and by relevant aldehyde dehydrogenase (ALDH) isozymes, remain undefined. ADH and ALDH both exhibit racially distinct allozymes and tissue-specific distribution of isozymes, and are principal enzymes responsible for ethanol metabolism in humans. In this study, we investigated acetaminophen inhibition of ethanol oxidation with recombinant human ADH1A, ADH1B1, ADH1B2, ADH1B3, ADH1C1, ADH1C2, ADH2, and ADH4, and inhibition of acetaldehyde oxidation with recombinant human ALDH1A1 and ALDH2. The investigations were done at near physiological pH 7.5 and with a cytoplasmic coenzyme concentration of 0.5 mM NAD(+). Acetaminophen acted as a noncompetitive inhibitor for ADH enzymes, with the slope inhibition constants (Kis) ranging from 0.90 mM (ADH2) to 20 mM (ADH1A), and the intercept inhibition constants (Kii) ranging from 1.4 mM (ADH1C allozymes) to 19 mM (ADH1A). Acetaminophen exhibited noncompetitive inhibition for ALDH2 (Kis = 3.0 mM and Kii = 2.2 mM), but competitive inhibition for ALDH1A1 (Kis = 0.96 mM). The metabolic interactions between acetaminophen and ethanol/acetaldehyde were assessed by computer simulation using inhibition equations and the determined kinetic constants. At therapeutic to subtoxic plasma levels of acetaminophen (i.e., 0.2-0.5 mM) and physiologically relevant concentrations of ethanol (10 mM) and acetaldehyde (10 μm) in target tissues, acetaminophen could inhibit ADH1C allozymes (12-26%) and ADH2 (14-28%) in the liver and small intestine, ADH4 (15-31%) in the stomach, and ALDH1A1 (16-33%) and ALDH2 (8.3-19%) in all 3 tissues. The

  12. Application of a first-pass effect model to characterize the pharmacokinetic disposition of venlafaxine after oral administration to human subjects.

    Science.gov (United States)

    Taft, D R; Iyer, G R; Behar, L; DiGregorio, R V

    1997-10-01

    Venlafaxine (VEN), a drug used in the treatment of depression, undergoes significant first-pass metabolism after oral dosing to O-desmethylvenlafaxine (ODV), a metabolite with comparable therapeutic activity to that of parent drug. The pharmacokinetic disposition of VEN was characterized using a "first-pass" model that incorporates a presystemic compartment (liver) to account for the first-pass metabolism of VEN to ODV. A series of differential equations were simultaneously fitted to plasma concentrations of parent and metabolite. A good fit of the model to observed data was demonstrated, generating estimates for the following parameters: ka (1.31 +/- 0.009 hr-1), VVEN (252 +/- 87.6 liters), CLint (65.8 +/- 39.7 liters/hr), RL (liver:plasma partition coefficient, 29.6 +/- 18. 3), VODV (181 +/- 84.1 liters), and CLODV (23.5 +/- 12.5 liters/hr). Parameter estimates correlated closely with those obtained through noncompartmental methods. These results indicate that the time-course disposition of a compound undergoing first-pass hepatic metabolism after oral dosing can be successfully modeled.

  13. Enrofloxacin and marbofloxacin in horses: comparison of pharmacokinetic parameters, use of urinary and metabolite data to estimate first-pass effect and absorbed fraction.

    Science.gov (United States)

    Peyrou, M; Bousquet-Melou, A; Laroute, V; Vrins, A; Doucet, M Y

    2006-10-01

    Enrofloxacin and marbofloxacin are two veterinary fluoroquinolones used to treat severe bacterial infections in horses. A repeated measures study has been designed to compare their pharmacokinetic parameters, to investigate their bioavailability and to estimate their absorbed fraction and first-pass effect by using plasma, urinary and metabolite data collected from five healthy mares. Clearance and V(d(ss)) were greater for enrofloxacin (mean +/- SD = 6.34 +/- 1.5 mL/min/kg and 2.32 +/- 0.32 L/kg, respectively) than for marbofloxacin (4.62 +/- 0.67 mL/min/kg and 1.6 +/- 0.25 L/kg, respectively). Variance of the AUC(0-inf) of marbofloxacin was lower than that for enrofloxacin, with, respectively, a CV = 15% and 26% intravenously and a CV = 31% and 55% after oral administration. Mean oral bioavailability was not significantly different between marbofloxacin (59%) and enrofloxacin (55%). The mean percentage of the dose eliminated unchanged in urine was significantly higher for marbofloxacin (39.7%) than that for enrofloxacin (3.4%). Absorbed fraction and first-pass effect were only determinable for enrofloxacin, whereas the percentage of the dose absorbed in the portal circulation was estimated to be 78% and the fraction not extracted during the first pass through the liver was 65%. Consequently, the moderate observed bioavailability of enrofloxacin appears to be mainly caused by hepatic first-pass effect.

  14. Renal perfusion scintiscan

    Science.gov (United States)

    Renal perfusion scintigraphy; Radionuclide renal perfusion scan; Perfusion scintiscan - renal; Scintiscan - renal perfusion ... supply the kidneys. This is a condition called renal artery stenosis. Significant renal artery stenosis may be ...

  15. Quantification of myocardial perfusion using free-breathing MRI and prospective slice tracking

    DEFF Research Database (Denmark)

    Pedersen, Henrik; Kelle, Sebastian; Ringgaard, Steffen

    2009-01-01

    Quantification of myocardial perfusion using first-pass magnetic resonance imaging (MRI) is hampered by respiratory motion of the heart. Prospective slice tracking (PST) potentially overcomes this problem, and may provide an attractive alternative or supplement to current breath-hold techniques...

  16. Dynamic CT perfusion measurement in a cardiac phantom.

    Science.gov (United States)

    Ziemer, Benjamin P; Hubbard, Logan; Lipinski, Jerry; Molloi, Sabee

    2015-10-01

    Widespread clinical implementation of dynamic CT myocardial perfusion has been hampered by its limited accuracy and high radiation dose. The purpose of this study was to evaluate the accuracy and radiation dose reduction of a dynamic CT myocardial perfusion technique based on first pass analysis (FPA). To test the FPA technique, a pulsatile pump was used to generate known perfusion rates in a range of 0.96-2.49 mL/min/g. All the known perfusion rates were determined using an ultrasonic flow probe and the known mass of the perfusion volume. FPA and maximum slope model (MSM) perfusion rates were measured using volume scans acquired from a 320-slice CT scanner, and then compared to the known perfusion rates. The measured perfusion using FPA (P(FPA)), with two volume scans, and the maximum slope model (P(MSM)) were related to known perfusion (P(K)) by P(FPA) = 0.91P(K) + 0.06 (r = 0.98) and P(MSM) = 0.25P(K) - 0.02 (r = 0.96), respectively. The standard error of estimate for the FPA technique, using two volume scans, and the MSM was 0.14 and 0.30 mL/min/g, respectively. The estimated radiation dose required for the FPA technique with two volume scans and the MSM was 2.6 and 11.7-17.5 mSv, respectively. Therefore, the FPA technique can yield accurate perfusion measurements using as few as two volume scans, corresponding to approximately a factor of four reductions in radiation dose as compared with the currently available MSM. In conclusion, the results of the study indicate that the FPA technique can make accurate dynamic CT perfusion measurements over a range of clinically relevant perfusion rates, while substantially reducing radiation dose, as compared to currently available dynamic CT perfusion techniques.

  17. An in vitro digestion test that reflects rat intestinal conditions to probe the importance of formulation digestion vs first pass metabolism in Danazol bioavailability from lipid based formulations.

    Science.gov (United States)

    Anby, Mette U; Nguyen, Tri-Hung; Yeap, Yan Yan; Feeney, Orlagh M; Williams, Hywel D; Benameur, Hassan; Pouton, Colin W; Porter, Christopher J H

    2014-11-03

    The impact of gastrointestinal (GI) processing and first pass metabolism on danazol oral bioavailability (BA) was evaluated after administration of self-emulsifying drug delivery systems (SEDDS) in the rat. Danazol absolute BA was determined following oral and intraduodenal (ID) administration of LFCS class IIIA medium chain (MC) formulations at high (SEDDSH-III) and low (SEDDSL-III) drug loading and a lipid free LFCS class IV formulation (SEDDS-IV). Experiments were conducted in the presence and absence of ABT (1-aminobenzotriazole) to evaluate the effect of first pass metabolism. A series of modified in vitro lipolysis tests were developed to better understand the in vivo processing of SEDDS in the rat. Danazol BA was low (digestion models based on the lower enzyme activity and lower dilution conditions expected in the rat resulted in significantly reduced danazol precipitation from SEDDS-III or SEDDS-IV on initiation of digestion. At the doses administered here (4-8 mg/kg), the primary limitation to danazol oral BA in the rat was first pass metabolism, and the fraction absorbed was >45% after oral administration of SEDDS-III or SEDDS-IV. In contrast, previous studies in dogs suggest that danazol BA is less dependent on first pass metabolism and more sensitive to changes in formulation processing. In vitro digestion models based on likely rat GI conditions suggest less drug precipitation on formulation digestion when compared to equivalent dog models, consistent with the increases in in vivo exposure (fraction absorbed) seen here in ABT-pretreated rats.

  18. High-resolution imaging of pulmonary ventilation and perfusion with {sup 68}Ga-VQ respiratory gated (4-D) PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Callahan, Jason [Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne, VIC (Australia); Hofman, Michael S. [The University of Melbourne, Department of Medicine, Peter MacCallum Cancer Centre, Centre for Molecular Imaging, East Melbourne, VIC (Australia); Siva, Shankar [The University of Melbourne, Peter MacCallum Cancer Centre, Department of Radiation Oncology, East Melbourne, VIC (Australia); The University of Melbourne, Sir Peter MacCallum Department of Oncology, East Melbourne, VIC (Australia); Kron, Tomas [The University of Melbourne, Sir Peter MacCallum Department of Oncology, East Melbourne, VIC (Australia); The University of Melbourne, Peter MacCallum Cancer Centre, Department of Physical Sciences, East Melbourne, VIC (Australia); Schneider, Michal E. [Monash University, Department of Medical Imaging and Radiation Science, Clayton, VIC (Australia); Binns, David; Eu, Peter [Peter MacCallum Cancer Centre, Centre for Cancer Imaging, East Melbourne, VIC (Australia); Hicks, Rodney J. [The University of Melbourne, Sir Peter MacCallum Department of Oncology, Peter MacCallum Cancer Centre, Centre for Molecular Imaging, East Melbourne, VIC (Australia)

    2014-02-15

    Our group has previously reported on the use of {sup 68}Ga-ventilation/perfusion (VQ) PET/CT scanning for the diagnosis of pulmonary embolism. We describe here the acquisition methodology for {sup 68}Ga-VQ respiratory gated (4-D) PET/CT and the effects of respiratory motion on image coregistration in VQ scanning. A prospective study was performed in 15 patients with non-small-cell lung cancer. 4-D PET and 4-D CT images were acquired using an infrared marker on the patient's abdomen as a surrogate for breathing motion following inhalation of Galligas and intravenous administration of {sup 68}Ga-macroaggregated albumin. Images were reconstructed with phase-matched attenuation correction. The lungs were contoured on CT and PET VQ images during free-breathing (FB) and at maximum inspiration (Insp) and expiration (Exp). The similarity between PET and CT volumes was measured using the Dice coefficient (DC) comparing the following groups; (1) FB-PET/CT, (2) InspPET/InspCT, (3) ExpPET/Exp CT, and (4) FB-PET/AveCT. A repeated measures one-way ANOVA with multiple comparison Tukey tests were performed to evaluate any difference between the groups. Diaphragmatic motion in the superior-inferior direction on the 4-D CT scan was also measured. 4-D VQ scanning was successful in all patients without additional acquisition time compared to the nongated technique. The highest volume overlap was between ExpPET and ExpCT and between FB-PET and AveCT with a DC of 0.82 and 0.80 for ventilation and perfusion, respectively. This was significantly better than the DC comparing the other groups (0.78-0.79, p < 0.05). These values agreed with a visual inspection of the images with improved image coregistration around the lung bases. The diaphragmatic motion during the 4-D CT scan was highly variable with a range of 0.4-3.4 cm (SD 0.81 cm) in the right lung and 0-2.8 cm (SD 0.83 cm) in the left lung. Right-sided diaphragmatic nerve palsy was observed in 3 of 15 patients. {sup 68}Ga-VQ 4-D

  19. Magnetic resonance perfusion imaging without contrast media

    Energy Technology Data Exchange (ETDEWEB)

    Martirosian, Petros; Graf, Hansjoerg; Schick, Fritz [University Hospital of Tuebingen, Section on Experimental Radiology, Tuebingen (Germany); Boss, Andreas; Schraml, Christina; Schwenzer, Nina F.; Claussen, Claus D. [University Hospital of Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany)

    2010-08-15

    Principles of magnetic resonance imaging techniques providing perfusion-related contrast weighting without administration of contrast media are reported and analysed systematically. Especially common approaches to arterial spin labelling (ASL) perfusion imaging allowing quantitative assessment of specific perfusion rates are described in detail. The potential of ASL for perfusion imaging was tested in several types of tissue. After a systematic comparison of technical aspects of continuous and pulsed ASL techniques the standard kinetic model and tissue properties of influence to quantitative measurements of perfusion are reported. For the applications demonstrated in this paper a flow-sensitive alternating inversion recovery (FAIR) ASL perfusion preparation approach followed by true fast imaging with steady precession (true FISP) data recording was developed and implemented on whole-body scanners operating at 0.2, 1.5 and 3 T for quantitative perfusion measurement in various types of tissue. ASL imaging provides a non-invasive tool for assessment of tissue perfusion rates in vivo. Images recorded from kidney, lung, brain, salivary gland and thyroid gland provide a spatial resolution of a few millimetres and sufficient signal to noise ratio in perfusion maps after 2-5 min of examination time. Newly developed ASL techniques provide especially high image quality and quantitative perfusion maps in tissues with relatively high perfusion rates (as also present in many tumours). Averaging of acquisitions and image subtraction procedures are mandatory, leading to the necessity of synchronization of data recording to breathing in abdominal and thoracic organs. (orig.)

  20. Pedal angiography in peripheral arterial occlusive disease: first-pass i.v. contrast-enhanced MR angiography with blood pool contrast medium versus intraarterial digital subtraction angiography.

    Science.gov (United States)

    Kos, Sebastian; Reisinger, Clemens; Aschwanden, Markus; Bongartz, Georg M; Jacob, Augustinus L; Bilecen, Deniz

    2009-03-01

    The purpose of this study was to prospectively evaluate first-pass i.v. gadofosveset-enhanced MR angiography in patients with peripheral arterial occlusive disease for visualization of the pedal arteries and stenosis or occlusion of those arteries with intraarterial digital subtraction angiography as the reference standard. Twenty patients with peripheral arterial occlusive disease (nine women, 11 men; age-range 58-83 years) were prospectively enrolled. Gadofosveset first-pass contrast-enhanced MR angiography was performed with a 1.5-T system, a dedicated foot coil, and cuff compression to the calf. Arterial segments were assessed for degree of arterial stenosis, arterial visibility, diagnostic utility, and venous contamination. Detection of vessel stenosis or occlusion was evaluated in comparison with findings at digital subtraction angiography. The unpaired Student's t test was used to test arterial visibility with the two techniques. First-pass MR angiography with gadofosveset had good diagnostic utility in 83.9% of all segments and no venous contamination in 96.8% of all segments. There was no difference between the performance of intraarterial digital subtraction angiography and that of i.v. contrast-enhanced MR angiography in arterial visibility overall (p = 0.245) or in subgroup analysis of surgical arterial bypass targets (p = 0.202). The overall sensitivity, specificity, and accuracy of i.v. gadofosveset-enhanced MR angiography for characterization of clinically significant stenosis and occlusion were 91.4%, 96.1%, and 93.9%. In the subgroup analysis, the sensitivity, specificity, and accuracy were 85.5%, 96.5%, and 92.1%. Gadofosveset-enhanced MR angiography of the pedal arteries in patients with peripheral arterial occlusive disease has arterial visibility equal to that of digital subtraction angiography and facilitates depiction of clinically significant stenosis and occlusion.

  1. Non-ECG-gated myocardial perfusion MRI using continuous magnetization-driven radial sampling.

    Science.gov (United States)

    Sharif, Behzad; Dharmakumar, Rohan; Arsanjani, Reza; Thomson, Louise; Bairey Merz, C Noel; Berman, Daniel S; Li, Debiao

    2014-12-01

    Establishing a high-resolution non-ECG-gated first-pass perfusion (FPP) cardiac MRI technique may improve accessibility and diagnostic capability of FPP imaging. We propose a non-ECG-gated FPP imaging technique using continuous magnetization-driven golden-angle radial acquisition. The main purpose of this preliminary study is to evaluate whether, in the simple case of single-slice two-dimensional imaging, adequate myocardial contrast can be obtained for accurate visualization of hypoperfused territories in the setting of myocardial ischemia. A T1-weighted pulse sequence with continuous golden-angle radial sampling was developed for non-ECG-gated FPP imaging. A sliding-window scheme with no temporal acceleration was used to reconstruct 8 frames/s. Canines were imaged at 3T with and without coronary stenosis using the proposed scheme and a conventional magnetization-prepared ECG-gated FPP method. Our studies showed that the proposed non-ECG-gated method is capable of generating high-resolution (1.7 × 1.7 × 6 mm(3) ) artifact-free FPP images of a single slice at high heart rates (92 ± 21 beats/min), while matching the performance of conventional FPP imaging in terms of hypoperfused-to-normal myocardial contrast-to-noise ratio (proposed: 5.18 ± 0.70, conventional: 4.88 ± 0.43). Furthermore, the detected perfusion defect areas were consistent with the conventional FPP images. Non-ECG-gated FPP imaging using optimized continuous golden-angle radial acquisition achieves desirable image quality (i.e., adequate myocardial contrast, high spatial resolution, and minimal artifacts) in the setting of ischemia. © 2014 Wiley Periodicals, Inc.

  2. Feasibility of perfusion cardiovascular magnetic resonance in paediatric patients

    Directory of Open Access Journals (Sweden)

    Kellenberger Christian

    2009-01-01

    Full Text Available Abstract Aims As coronary artery disease may also occur during childhood in some specific conditions, we sought to assess the feasibility and accuracy of perfusion cardiovascular magnetic resonance (CMR in paediatric patients. Methods and results First-pass perfusion CMR studies were performed under pharmacological stress with adenosine and by using a hybrid echo-planar pulse sequence with slice-selective saturation recovery preparation. Fifty-six perfusion CMR examinations were performed in 47 patients. The median age was 12 years (1 month-18 years, and weight 42.8 kg (2.6-82 kg. General anaesthesia was required in 18 patients. Mean examination time was 67 ± 19 min. Diagnostic image quality was obtained in 54/56 examinations. In 23 cases the acquisition parameters were adapted to patient's size. Perfusion CMR was abnormal in 16 examinations. The perfusion defects affected the territory of the left anterior descending coronary artery in 11, of the right coronary artery in 3, and of the circumflex coronary artery in 2 cases. Compared to coronary angiography, perfusion CMR showed a sensitivity of 87% (CI 52-97% and a specificity of 95% (CI 79-99%. Conclusion In children, perfusion CMR is feasible and accurate. In very young children (less than 1 year old, diagnostic image quality may be limited.

  3. Gut Wall Metabolism. Application of Pre-Clinical Models for the Prediction of Human Drug Absorption and First-Pass Elimination.

    Science.gov (United States)

    Jones, Christopher R; Hatley, Oliver J D; Ungell, Anna-Lena; Hilgendorf, Constanze; Peters, Sheila Annie; Rostami-Hodjegan, Amin

    2016-05-01

    Quantifying the multiple processes which control and modulate the extent of oral bioavailability for drug candidates is critical to accurate projection of human pharmacokinetics (PK). Understanding how gut wall metabolism and hepatic elimination factor into first-pass clearance of drugs has improved enormously. Typically, the cytochrome P450s, uridine 5'-diphosphate-glucuronosyltransferases and sulfotransferases, are the main enzyme classes responsible for drug metabolism. Knowledge of the isoforms functionally expressed within organs of first-pass clearance, their anatomical topology (e.g. zonal distribution), protein homology and relative abundances and how these differ across species is important for building models of human metabolic extraction. The focus of this manuscript is to explore the parameters influencing bioavailability and to consider how well these are predicted in human from animal models or from in vitro to in vivo extrapolation. A unique retrospective analysis of three AstraZeneca molecules progressed to first in human PK studies is used to highlight the impact that species differences in gut wall metabolism can have on predicted human PK. Compared to the liver, pharmaceutical research has further to go in terms of adopting a common approach for characterisation and quantitative prediction of intestinal metabolism. A broad strategy is needed to integrate assessment of intestinal metabolism in the context of typical DMPK activities ongoing within drug discovery programmes up until candidate drug nomination.

  4. Evaluation of heart perfusion in patients with acute myocardial infarction using dynamic contrast-enhanced magnetic resonance imaging

    DEFF Research Database (Denmark)

    Nielsen, Gitte; Fritz-Hansen, Thomas; Dirks, Christina G

    2004-01-01

    with acute transmural myocardial infarction were studied using a Turbo-fast low angle shot (FLASH) MRI sequence to monitor the first pass of an extravascular contrast agent (CA), gadolinium diethylene triamine pentaacetic acid (Gd-DTPA). Quantitation of perfusion, expressed as Ki (mL/100 g/minute), in five...

  5. Optimal Duration of Acquisition for Dynamic Perfusion CT Assessment of Blood-Brain Barrier Permeability Using the Patlak Model

    NARCIS (Netherlands)

    Hom, J.; Dankbaar, J. W.; Schneider, T.; Cheng, S. -C.; Bredno, J.; Wintermark, M.

    2009-01-01

    BACKGROUND AND PURPOSE: A previous study demonstrated the need to use delayed acquisition rather than first-pass data for accurate blood-brain barrier permeability surface product (BBBP) calculation from perfusion CT (PCT) according to the Patlak model, but the optimal duration of the delayed acquis

  6. Performance of simultaneous high temporal resolution quantitative perfusion imaging of bladder tumors and conventional multi-phase urography using a novel free-breathing continuously acquired radial compressed-sensing MRI sequence.

    Science.gov (United States)

    Parikh, Nainesh; Ream, Justin M; Zhang, Hoi Cheung; Block, Kai Tobias; Chandarana, Hersh; Rosenkrantz, Andrew B

    2016-06-01

    To investigate the feasibility of high temporal resolution quantitative perfusion imaging of bladder tumors performed simultaneously with conventional multi-phase MR urography (MRU) using a novel free-breathing continuously acquired radial MRI sequence with compressed-sensing reconstruction. 22 patients with bladder lesions underwent MRU using GRASP (Golden-angle RAdial Sparse Parallel) acquisition. Multi-phase contrast-enhanced abdominopelvic GRASP was performed during free-breathing (1.4×1.4×3.0mm(3) voxel size; 3:44min acquisition). Two dynamic datasets were retrospectively reconstructed by combining different numbers of sequentially acquired spokes into each dynamic frame: 110 spokes per frame for 25-s temporal resolution (serving as conventional MRU for clinical interpretation) and 8 spokes per frame for 1.7-s resolution. Using 1.7-s resolution images, ROIs were placed within bladder lesions and normal bladder wall, a femoral artery arterial input function was generated, and the Generalized Kinetic Model was applied. Biopsy/cystectomy demonstrated 16 bladder tumors (13 stage≥T2, 3 stage≤T1) and 6 benign lesions. All lesions were well visualized using 25-s clinical multi-phase images. Using 1.7-s resolution images, K(trans) was significantly higher in tumors (0.38±0.24) than normal bladder (0.12±0.02=8, pMRU examinations using only one contrast injection and without additional scan time. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. A new method to evaluate ischemic heart disease. Combined use of rest thallium-201 myocardial SPECT and Tc-99m exercise tetrofosmin first pass and myocardial SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong-ih; Goto, Hideki; Kobayashi, Katsuhiro; Sawada, Yoshihiro; Miyake, Yoshitaka; Fujiwara, Go [Nishiyodo Hospital, Osaka (Japan); Okada, Tomoya; Nishimura, Tsunehiko

    1999-06-01

    We developed a new diagnostic method for simultaneously evaluating myocardial ischemia, myocardial viability and ventricular function in less than 90 minutes by combined use of rest thallium-201 (Tl) SPECT and exercise Tc-99m tetrofosmin (TF) first pass and SPECT. The subjects were 9 healthy controls, 19 angina pectoris patients, and 19 old myocardial infarction patients, in all of whom coronary angiography had been performed. Rest Tl myocardial SPECT was performed first, and was followed by exercise TF myocardial SPECT. We also performed first pass radionuclide angiography by TF during maximum exercise on a bicycle ergometer to assess the left ventricular ejection fraction (LVEF). The total examination time was less than 90 minutes. SPECT diagnosis was performed by semi-quantitative analysis. LVEF below 55% was regarded as abnormal. In the patients with angina pectoris, analysis according to the coronary artery showed that the diagnostic accuracy of SPECT was 85.0% for ischemia in the region of the left anterior descending branch (LAD), 87.5% for the left circumflex branch (LCX) and 77.8% for the right coronary artery (RCA). The accuracy of diagnosis for angina pectoris was 82.1%, as determined by SPECT alone, and rose to 89,3% when the LVEF levels were also taken into consideration. In the patients with old myocardial infarction, the diagnostic accuracy of SPECT was 84.2% for the LAD, 92.3% for the LCX and 85.0% for the RCA. Analysis by patients showed that the accuracy of diagnosis for myocardial infarction was 85.7%, as determined by SPECT alone. The diagnostic accuracy, however, rose to 89.3% when the LVEF levels also were taken into consideration. In conclusion, it was demonstrated that this combined diagnostic method was highly reliable for evaluating ischemic heart disease within a short time. (author)

  8. Regional lung perfusion estimated by electrical impedance tomography in a piglet model of lung collapse.

    Science.gov (United States)

    Borges, João Batista; Suarez-Sipmann, Fernando; Bohm, Stephan H; Tusman, Gerardo; Melo, Alexandre; Maripuu, Enn; Sandström, Mattias; Park, Marcelo; Costa, Eduardo L V; Hedenstierna, Göran; Amato, Marcelo

    2012-01-01

    The assessment of the regional match between alveolar ventilation and perfusion in critically ill patients requires simultaneous measurements of both parameters. Ideally, assessment of lung perfusion should be performed in real-time with an imaging technology that provides, through fast acquisition of sequential images, information about the regional dynamics or regional kinetics of an appropriate tracer. We present a novel electrical impedance tomography (EIT)-based method that quantitatively estimates regional lung perfusion based on first-pass kinetics of a bolus of hypertonic saline contrast. Pulmonary blood flow was measured in six piglets during control and unilateral or bilateral lung collapse conditions. The first-pass kinetics method showed good agreement with the estimates obtained by single-photon-emission computerized tomography (SPECT). The mean difference (SPECT minus EIT) between fractional blood flow to lung areas suffering atelectasis was -0.6%, with a SD of 2.9%. This method outperformed the estimates of lung perfusion based on impedance pulsatility. In conclusion, we describe a novel method based on EIT for estimating regional lung perfusion at the bedside. In both healthy and injured lung conditions, the distribution of pulmonary blood flow as assessed by EIT agreed well with the one obtained by SPECT. The method proposed in this study has the potential to contribute to a better understanding of the behavior of regional perfusion under different lung and therapeutic conditions.

  9. MR mapping of temperature and perfusion for hyperthermia therapy

    Science.gov (United States)

    Wlodarczyk, Waldemar; Vlad, Julia; Lange, Thomas; Wust, Peter; Felix, Roland

    2001-05-01

    The promising results, recently obtained in phantom experiments employing the MR-based proton resonance frequency (PRF) method as a non-invasive tool for the temperature monitoring of hyperthermia therapy, are not easily reproduced in vivo. One of the reasons is the impact of perfusion changes on the PRF-measured temperature. In our experiments in vivo, heat was supplied on one side of the volunteers knee or pelvis by a rubber hose with circulating warm water (50iC). The PRF method was calibrated by the constant temperature sensitivity of pure water of 0.011 ppm/iC. MR mapping of perfusion changes was based on T2*-weighted tracking of the first-pass kinetics of contrast agent. The hemodynamic parameters of regional blood volume (rBV) and mean transit time (MTT) were extracted by fitting pixel-by-pixel the first- pass kinetics to the gamma-variate model. Special attention was directed to improve a quality of the automatic non-linear fit at low signal-to-noise values. The distributions of PRF- based temperature changes show large areas of apparently high temperature elevations (exceeding 10iC) in regions close to the heat source, and others with just as large temperature decays in more distant regions. Areas of apparently high temperature elevations correlate with areas of blood flow increase and vice versa. In conclusion, the visible heat- induced PRF changes in vivo are primarily perfusion changes, which mask the much smaller true temperature changes.

  10. Bubble dynamics in perfused tissue undergoing decompression.

    Science.gov (United States)

    Meisel, S; Nir, A; Kerem, D

    1981-02-01

    A mathematical model describing bubble dynamics in a perfused tissue undergoing decompression is presented, taking into account physical expansion and inward diffusion from surrounding supersaturated tissue as growth promoting factors and tissue gas elimination by perfusion, tissue elasticity, surface tension and inherent unsaturation as resolving driving forces. The expected behavior after a step reduction of pressure of a bubble initially existing in the tissue, displaying both growth and resolution has been demonstrated. A strong perfusion-dependence of bubble resolution time at low perfusion rates is apparent. The model can account for various exposure pressures and saturation fractions of any inert gas-tissue combination for which a set of physical and physiological parameters is available.

  11. Evaluation of right ventricular volume and mass using retrospective ECG-gated cardiac multidetector computed tomography: comparison with first-pass radionuclide angiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Hoon [Yonsei University College of Medicine, Department of Radiology, Seoul (Korea); Yongdong Severance Hospital, Department of Radiology, Seoul (Korea); Ryu, Young Hoon; Hur, Jin; Kim, Sang Jin; Kim, Hyun Soo; Choi, Byoung Wook [Yonsei University College of Medicine, Department of Radiology, Seoul (Korea); Kim, Young; Kim, Hyung Jung [Yonsei University College of Medicine, Department of Pulmonology, Seoul (Korea)

    2005-09-01

    The purposes of this study were to evaluate the right ventricular (RV) volume and mass using cardiac multidetector computed tomography (MDCT) and to compare the cardiac MDCT results with those from first-pass radionuclide angiography (FPRA). Twenty patients were evaluated for the RV end-diastolic volume (RVEDV), the RV end-systolic volume (RVESV), the RV ejection fraction (RVEF), and RV mass using cardiac MDCT with a two-phase reconstruction method based on ECG. The end-diastolic phase was reconstructed at the starting point of the QRS complex on ECG, and the end-systolic phase was reconstructed at the halfway point of the ascending T-wave on ECG. The RV mass was measured for the end-systole. The RVEF was also obtained by FPRA. The mean RVEF (47{+-}7%) measured by cardiac MDCT was well correlated with that (44{+-}6%) measured by FPRA (r=0.854). A significant difference in the mean RVEF was found between cardiac MDCT and FPRA (p=0.001), with an overestimation of 2.9{+-}5.3% by cardiac MDCT versus FPRA. The interobserver variability was 4.4% for the RVEDV, 6.8% for the RVESV, and 7.9% for the RV mass, respectively. Cardiac MDCT is relatively simple and allows the RV volume and mass to be assessed, and the RVEF obtained by cardiac MDCT correlates well with that measured by FPRA. (orig.)

  12. Value of T2-weighted, first-pass and delayed enhancement, and cine CMR to differentiate between acute and chronic myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Stork, Alexander; Bansmann, Paul M.; Kaul, Michael; Kemper, Joern; Adam, Gerhard [University Hospital Hamburg-Eppendorf, Department of Diagnostic and Interventional Radiology, Hamburg (Germany); Muellerleile, Kai; Lund, Gunnar K. [Heart Center, University Hospital Hamburg-Eppendorf, Department of Cardiology/Angiology, Hamburg (Germany); Graessner, Joachim [Siemens Medical Solutions, Hamburg (Germany)

    2007-03-15

    The aim of this study was to analyze the diagnostic accuracy of edema on T2-weighted (T2w) cardiac magnetic resonance imaging (CMR), presence of microvascular obstruction (MO) on first-pass enhancement (FPE) or on delayed enhancement (DE) CMR, and wall thinning on cine CMR to differentiate between acute (AMI) and chronic myocardial infarction (CMI) in patients with infarction on DE-CMR. Fifty patients were imaged 5 {+-} 3 days (baseline) and 8 {+-} 3 months (follow-up) after AMI at 1.5 T. Imaging findings were graded as present or absent in a blinded consensus reading. Edema was present at baseline in 48 (96%) patients and absent at follow-up in 49 (98%) patients. At baseline, MO was present in 29 (58%) patients on FPE-CMR and in 24 (48%) patients on DE-CMR (P = ns). At follow-up, persisting hypoenhancement was observed in ten (20%) patients on FPE-CMR, whereas two (4%) patients showed persisting hypoenhancement on DE-CMR (P<0.05). Wall thinning was present in 4 (8%) patients at baseline and in 20 (40%) patients at follow-up. Edema had high sensitivity (96%), specificity (98%), and accuracy (97%) to differentiate between AMI and CMI. Accuracy of all other imaging findings was lower compared to that of edema (P<0.001). In the presence of infarction on DE-CMR, T2w-CMR reliably differentiates between AMI and CMI. (orig.)

  13. Measurement of myocardial perfusion using magnetic resonance

    DEFF Research Database (Denmark)

    Fritz-Hansen, T.; Jensen, L.T.; Larsson, H.B.

    2008-01-01

    Cardiac magnetic resonance imaging (MRI) has evolved rapidly. Recent developments have made non-invasive quantitative myocardial perfusion measurements possible. MRI is particularly attractive due to its high spatial resolution and because it does not involve ionising radiation. This paper reviews...... myocardial perfusion imaging with MR contrast agents: methods, validation and experiences from clinical studies. Unresolved issues still restrict the use of these techniques to research although clinical applications are within reach Udgivelsesdato: 2008/12/8...

  14. Pulmonary ventilation/perfusion scan

    Science.gov (United States)

    V/Q scan; Ventilation/perfusion scan; Lung ventilation/perfusion scan ... A pulmonary ventilation/perfusion scan is actually two tests. They may be done separately or together. During the perfusion scan, a health care provider injects ...

  15. Inhibition of human alcohol and aldehyde dehydrogenases by aspirin and salicylate: assessment of the effects on first-pass metabolism of ethanol.

    Science.gov (United States)

    Lee, Shou-Lun; Lee, Yung-Pin; Wu, Min-Li; Chi, Yu-Chou; Liu, Chiu-Ming; Lai, Ching-Long; Yin, Shih-Jiun

    2015-05-01

    Previous studies have reported that aspirin significantly reduced the first-pass metabolism (FPM) of ethanol in humans thereby increasing adverse effects of alcohol. The underlying causes, however, remain poorly understood. Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), principal enzymes responsible for metabolism of ethanol, are complex enzyme families that exhibit functional polymorphisms among ethnic groups and distinct tissue distributions. We investigated the inhibition profiles by aspirin and its major metabolite salicylate of ethanol oxidation by recombinant human ADH1A, ADH1B1, ADH1B2, ADH1B3, ADH1C1, ADH1C2, ADH2, and ADH4, and acetaldehyde oxidation by ALDH1A1 and ALDH2, at pH 7.5 and 0.5 mM NAD(+). Competitive inhibition pattern was found to be a predominant type among the ADHs and ALDHs studied, although noncompetitive and uncompetitive inhibitions were also detected in a few cases. The inhibition constants of salicylate for the ADHs and ALDHs were considerably lower than that of aspirin with the exception of ADH1A that can be ascribed to a substitution of Ala-93 at the bottom of substrate pocket as revealed by molecular docking experiments. Kinetic inhibition equation-based simulations show at higher therapeutic levels of blood plasma salicylate (1.5 mM) that the decrease of activities at 2-10 mM ethanol for ADH1A/ADH2 and ADH1B2/ADH1B3 are predicted to be 75-86% and 31-52%, respectively, and that the activity decline for ALDH1A1 and ALDH2 at 10-50 μM acetaldehyde to be 62-73%. Our findings suggest that salicylate may substantially inhibit hepatic FPM of alcohol at both the ADH and ALDH steps when concurrent intaking aspirin. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Pharmacokinetics of mangiferin and its metabolite-Norathyriol, Part 1: Systemic evaluation of hepatic first-pass effect in vitro and in vivo.

    Science.gov (United States)

    Tian, Xiaoting; Gao, Yu; Xu, Zhou; Lian, Shan; Ma, Yuanjie; Guo, Xiaozhen; Hu, Pei; Li, Zhixiong; Huang, Chenggang

    2016-09-10

    Mangiferin (MGF), a glucoside of xanthone existing in phytomedicines and food, is increasingly attracting attention on diabetes treatment, while the underlying mechanism leading to its low oral bioavailability is unclear. Norathyriol (NTR), an active metabolite with hypoglycemic activity and its exposure after MGF dosing remains unclear. Hence, a rapid and sensitive LC-MS/MS method was established and validated to determine MGF and NTR and applied in the PK study in rats. Correspondingly, the in vitro experiments on temperature-dependent uptake, and MGF metabolism in hepatocyte and enterobacteria samples were performed. Results revealed that hepatic first-pass effect slightly contributed to the poor bioavailability of MGF, based on the MGF exposure in portal vein plasma was nearly similar to that in systemic plasma, and the MGF accumulation in the liver was limited, so was that of NTR. Correspondingly, the in vitro study revealed the MGF uptake was mainly dependent on poor passive transport, possibly leading to its limited hepatic metabolism and accumulation. Moreover, the NTR exposure remained considerably low (Cmax  < 3 ng/mL, AUCNTR /AUCMGF  < 3%) in plasma after single MGF dosing, corresponding to its tiny proportion (0.1%) of MGF in MGF-incubated enterobacteria samples. However, given the low generation and elimination rates of NTR, NTR might accumulate in plasma and exert effects after repeated MGF dosing, although requires further study. This work is the first systemic study on PK profiles of MGF and NTR in vitro and in vivo, which is important for the interpretation on the poor bioavailability and pharmacodynamics of MGF. © 2016 BioFactors, 42(5):533-544, 2016.

  17. Involvement of cytochrome P450 3A4 and P-glycoprotein in first-pass intestinal extraction of omeprazole in rabbits

    Institute of Scientific and Technical Information of China (English)

    Hai-ming FANG; Jian-ming XU; Qiao MEI; Lei DIAO; Mo-li CHEN; Juan JIN; Xin-hua XU

    2009-01-01

    Aim: To quantitatively evaluate in vivo first-pass intestinal extraction of omeprazole and to investigate the possible involvement of cytochrome P450 3A4 (CYP3A4) and P-glycoprotein (P-gp) in this process in rabbits.Methods: Pharmacokinetic parameters were examined after intraduodenal (id), intraportal venous (ipv), and intravenous (iv) administration of omeprazole at various doses to intestinal and vascular access-ported rabbits. Extraction ratios in the liver and intestinal tract were determined from the area under the plasma concentration-time curve (AUC). In addition, omeprazole was administered by id or iv to rabbits alone or 30 min after the id administration of CYP3A4 or P-gp inhibitors (ketoconazole or verapamil, respectively). Results: Pharmacokinetic parameters of omeprazole were dose-dependent after id, ipv, and iv administration at various doses. After id administration of 3 mg/kg omeprazole, the hepatic and intestinal extraction ratio was 57.18%±2.73% and 54.94%±1.85%, while the value was 59.29%±3.14% and 54.20%±1.53% after given 6 mg/kg, respectively. Compared with the control group, the presence of ketoconazole (60 mg/kg) or verapamil (9 mg/kg) significantly increased the area under the plasma concentration time curve (AUC) and the peak concentration (C_(max)) of id-administered omeprazole, while it had no significant effect on omeprazole administered by iv. Conclusion: Oral omeprazole undergoes marked extraction in the small intestine, and increased bioavailability of the drug after id administration of ketoconazole and verapamil suggests that this increase results from inhibition of CYP3A4 and P-gp function in the intestine rather than the liver.

  18. Human carbonyl reductase 1 participating in intestinal first-pass drug metabolism is inhibited by fatty acids and acyl-CoAs.

    Science.gov (United States)

    Hara, Akira; Endo, Satoshi; Matsunaga, Toshiyuki; El-Kabbani, Ossama; Miura, Takeshi; Nishinaka, Toru; Terada, Tomoyuki

    2017-08-15

    Human carbonyl reductase 1 (CBR1), a member of the short-chain dehydrogenase/reductase (SDR) superfamily, reduces a variety of carbonyl compounds including endogenous isatin, prostaglandin E2 and 4-oxo-2-nonenal. It is also a major non-cytochrome P450 enzyme in the phase I metabolism of carbonyl-containing drugs, and is highly expressed in the intestine. In this study, we found that long-chain fatty acids and their CoA ester derivatives inhibit CBR1. Among saturated fatty acids, myristic, palmitic and stearic acids were inhibitory, and stearic acid was the most potent (IC50 9µM). Unsaturated fatty acids (oleic, elaidic, γ-linolenic and docosahexaenoic acids) and acyl-CoAs (palmitoyl-, stearoyl- and oleoyl-CoAs) were more potent inhibitors (IC50 1.0-2.5µM), and showed high inhibitory selectivity to CBR1 over its isozyme CBR3 and other SDR superfamily enzymes (DCXR and DHRS4) with CBR activity. The inhibition by these fatty acids and acyl-CoAs was competitive with respect to the substrate, showing the Ki values of 0.49-1.2µM. Site-directed mutagenesis of the substrate-binding residues of CBR1 suggested that the interactions between the fatty acyl chain and the enzyme's Met141 and Trp229 are important for the inhibitory selectivity. We also examined CBR1 inhibition by oleic acid in cellular levels: The fatty acid effectively inhibited CBR1-mediated 4-oxo-2-nonenal metabolism in colon cancer DLD1 cells and increased sensitivity to doxorubicin in the drug-resistant gastric cancer MKN45 cells that highly express CBR1. The results suggest a possible new food-drug interaction through inhibition of CBR1-mediated intestinal first-pass drug metabolism by dietary fatty acids. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. 优化缺血性脑卒中CT灌注成像的时间分辨力%Optimizing temporal resolution on dynamic perfusion CT in ischemic stroke

    Institute of Scientific and Technical Information of China (English)

    马春; 明兵; 王周璇; 孟义兴; 陈淑君; 官春兰

    2012-01-01

    目的 探讨通过降低CT灌注成像(CTP)采样时间分辨力对CTP灌注参数值准确性的影响而降低CTP扫描射线剂量的可行性.方法 对25例有缺血性脑卒中症状的患者进行CTP扫描,球管旋转速度为1转/秒,采样时间分辨力为1 s,采集方式为4i×7.2mm,共得到160幅图像.对原始数据(原始数据组)进行降低时间分辨力分组,分别为2、3、4及5 s组.使用Neuro PCT软件对5组数据进行后处理,各组选择相同ROI测量脑血流量(CBF)、脑血容量(CBV)及达峰时间(TTP),并与原始数据组处理结果进行比较.结果 随着时间分辨力降低,灌注参数伪彩图SNR降低.时间分辨力为2 s时,各灌注参数值与原始数据组比较差异无统计学意义;3 s及以下时间分辨力图像SNR降低趋于明显.随着时间分辨力降低,CTP扫描射线剂量明显降低.结论 CTP中,时间分辨力为2s时,仍能测得准确的灌注参数值,且可明显降低射线剂量.%To assess the influence of lowering temporal sampling rates of CT perfusion (CTP) on parameters for reducing the radiation dose. Methods Twenty-five patients with ischemic sufferings underwent CTP. Original sampling rate was 1 rotation per second. Data were acquired with 47.2 mm and totally 160 images were obtained. Additional four data sets were obtained with temporal resolution of2s.3s.4s.5s. respectively. Data sets were postprocessed with Neuro PCT. Cerebral blood flow (CBF), cerebral blood volume (CBV) and time to peak (TTP) were measured with the i-dentical ROI. The results of the four data sets were compared with that of the original data sets. Results Signal-noise ratio (SNR) of color-coded parameter maps for CBF. CBV and TTP were lowering as sampling rate reduced, especially under 3 s temporal resolution. All perfusion parameters of 2 s temporal resolution data sets did not differ with that of the original data sets. The radiation reduced significantly when temporal sampling rate decreased

  20. Research advances in models of hepatic and intestinal first-pass drug metabolism%肝脏和小肠对药物首过代谢模型的研究进展

    Institute of Scientific and Technical Information of China (English)

    朱晶; 郭建军; 林俊辉; 卜海之; 陈西敬

    2012-01-01

    Low oral bioavailability of a drug could be attributed to poor absorption and/or extensive first-pass metabolism. The liver and small intestine are the two most important organs for first-pass metabolism. In this review, the important drug-metabolizing enzymes located in the human liver and small intestine are introduced and the effects of different physiological structures of the two organs on overall first-pass metabolism are presented. Moreover, the re- search advances of the methods used to estimate hepatic and intestinal first-pass metabolism, such as in vitro , in situ, in vivo,in vitro-in vivo combined, knockout and transgenic models, are also summarized.%肝、肠首过代谢有时是药物口服生物利用度低的主要原因之一.本文介绍了肝脏和小肠中药物代谢酶的分布、含量和催化活性,比较了两者在生理结构上的差异对首过代谢的影响,对有关研究方法,包括体外、原位、体内、体外-体内结合以及基因敲除和转基因模型等方面的进展进行了概述.

  1. Measurement of myocardial perfusion using magnetic resonance

    DEFF Research Database (Denmark)

    Fritz-Hansen, T.; Jensen, L.T.; Larsson, H.B.;

    2008-01-01

    Cardiac magnetic resonance imaging (MRI) has evolved rapidly. Recent developments have made non-invasive quantitative myocardial perfusion measurements possible. MRI is particularly attractive due to its high spatial resolution and because it does not involve ionising radiation. This paper review...... myocardial perfusion imaging with MR contrast agents: methods, validation and experiences from clinical studies. Unresolved issues still restrict the use of these techniques to research although clinical applications are within reach Udgivelsesdato: 2008/12/8......Cardiac magnetic resonance imaging (MRI) has evolved rapidly. Recent developments have made non-invasive quantitative myocardial perfusion measurements possible. MRI is particularly attractive due to its high spatial resolution and because it does not involve ionising radiation. This paper reviews...

  2. A 4D CT digital phantom of an individual human brain for perfusion analysis

    NARCIS (Netherlands)

    Manniesing, R.; Brune, C.; Ginneken, B. van; Prokop, M.

    2016-01-01

    Brain perfusion is of key importance to assess brain function. Modern CT scanners can acquire perfusion maps of the cerebral parenchyma in vivo at submillimeter resolution. These perfusion maps give insights into the hemodynamics of the cerebral parenchyma and are critical for example for treatment

  3. Perfusion visualization and analysis for pulmonary embolism

    Science.gov (United States)

    Vaz, Michael S.; Kiraly, Atilla P.; Naidich, David P.; Novak, Carol L.

    2005-04-01

    Given the nature of pulmonary embolism (PE), timely and accurate diagnosis is critical. Contrast enhanced high-resolution CT images allow physicians to accurately identify segmental and sub-segmental emboli. However, it is also important to assess the effect of such emboli on the blood flow in the lungs. Expanding upon previous research, we propose a method for 3D visualization of lung perfusion. The proposed method allows users to examine perfusion throughout the entire lung volume at a single glance, with areas of diminished perfusion highlighted so that they are visible independent of the viewing location. This may be particularly valuable for better accuracy in assessing the extent of hemodynamic alterations resulting from pulmonary emboli. The method also facilitates user interaction and may help identify small peripheral sub-segmental emboli otherwise overlooked. 19 patients referred for possible PE were evaluated by CT following the administration of IV contrast media. An experienced thoracic radiologist assessed the 19 datasets with 17 diagnosed as being positive for PE with multiple emboli. Since anomalies in lung perfusion due to PE can alter the distribution of parenchymal densities, we analyzed features collected from histograms of the computed perfusion maps and demonstrate their potential usefulness as a preliminary test to suggest the presence of PE. These histogram features also offer the possibility of distinguishing distinct patterns associated with chronic PE and may even be useful for further characterization of changes in perfusion or overall density resulting from associated conditions such as pneumonia or diffuse lung disease.

  4. Unenhanced and Contrast-Enhanced MR Angiography and Perfusion Imaging for Suspected Pulmonary Thromboembolism.

    Science.gov (United States)

    Ohno, Yoshiharu; Yoshikawa, Takeshi; Kishida, Yuji; Seki, Shinichiro; Karabulut, Nevzat

    2017-03-01

    This article discusses the basics of unenhanced MR angiography (MRA) and MR venography (MRV), time-resolved contrast-enhanced (CE) MRA and dynamic first-pass CE perfusion MRI, and unenhanced and CE MRV, in addition to assessing the clinical relevance of these techniques for evaluating patients with suspected pulmonary thromboembolism and deep venous thrombosis. Since the 1990s, the efficacy of MRA or MRV and dynamic perfusion MRI for patients with suspected pulmonary thromboembolism and deep venous thrombosis has been evaluated. On the basis of the results of single-center trials, comprehensive MRI protocols, including pulmonary unenhanced and CE MRA, perfusion MRI, and MRV, promise to be safe and time effective for assessing patients with suspected pulmonary thromboembolism, although future multicenter trials are required to assess the real clinical value of MRI.

  5. High-resolution blood-pool-contrast-enhanced MR angiography in glioblastoma: tumor-associated neovascularization as a biomarker for patient survival. A preliminary study.

    Science.gov (United States)

    Puig, Josep; Blasco, Gerard; Daunis-I-Estadella, Josep; Alberich-Bayarri, Angel; Essig, Marco; Jain, Rajan; Remollo, Sebastián; Hernández, David; Puigdemont, Montserrat; Sánchez-González, Javier; Mateu, Gloria; Wintermark, Max; Pedraza, Salvador

    2016-01-01

    The objective of the study was to determine whether tumor-associated neovascularization on high-resolution gadofosveset-enhanced magnetic resonance angiography (MRA) is a useful biomarker for predicting survival in patients with newly diagnosed glioblastomas. Before treatment, 35 patients (25 men; mean age, 64 ± 14 years) with glioblastoma underwent MRI including first-pass dynamic susceptibility contrast (DSC) perfusion and post-contrast T1WI sequences with gadobutrol (0.1 mmol/kg) and, 48 h later, high-resolution MRA with gadofosveset (0.03 mmol/kg). Volumes of interest for contrast-enhancing lesion (CEL), non-CEL, and contralateral normal-appearing white matter were obtained, and DSC perfusion and DWI parameters were evaluated. Prognostic factors were assessed by Kaplan-Meier survival and Cox proportional hazards model. Eighteen (51.42 %) glioblastomas were hypervascular on high-resolution MRA. Hypervascular glioblastomas were associated with higher CEL volume and lower Karnofsky score. Median survival rates for patients with hypovascular and hypervascular glioblastomas treated with surgery, radiotherapy, and chemotherapy were 15 and 9.75 months, respectively (P contrast-enhanced MRA of newly diagnosed glioblastoma seems to be a useful biomarker that correlates with worse survival.

  6. Adiposity Is Associated with Gender-Specific Reductions in Left Ventricular Myocardial Perfusion during Dobutamine Stress.

    Directory of Open Access Journals (Sweden)

    Michael E Hall

    Full Text Available Obesity and visceral adiposity are increasingly recognized risk factors for cardiovascular disease. Visceral fat may reduce myocardial perfusion by impairing vascular endothelial function. Women experience more anginal symptoms compared to men despite less severe coronary artery stenosis, as assessed by angiography. Women and men have different fat storage patterns which may account for the observed differences in cardiovascular disease. Therefore, our objective was to evaluate the relationship between visceral adipose tissue distributions and myocardial perfusion in men and women.Visceral and subcutaneous fat distributions and myocardial perfusion were measured in 69 men and women without coronary artery disease using magnetic resonance imaging techniques. Myocardial perfusion index was quantified after first-pass perfusion with gadolinium contrast at peak dose dobutamine stress.We observed inverse relationships between female gender (r = -0.35, p = 0.003, pericardial fat (r = -0.36, p = 0.03, intraperitoneal fat (r = -0.37, p = 0.001, and retroperitoneal fat (r = -0.36, p = 0.002 and myocardial perfusion index. Visceral fat depots were not associated with reduced myocardial perfusion at peak dose dobutamine in men. However, in women, BMI (r = -0.33, p = 0.04, pericardial fat (r = -0.53, p = 0.02, subcutaneous fat (r = -0.39, p = 0.01 and intraperitoneal fat (r = -0.30, p = 0.05 were associated with reduced myocardial perfusion during dobutamine stress.Higher visceral fat volumes are associated with reduced left ventricular myocardial perfusion at peak dose dobutamine stress in women but not in men. These findings suggest that visceral fat may contribute to abnormal microcirculatory coronary artery perfusion syndromes, explaining why some women exhibit more anginal symptoms despite typically lower grade epicardial coronary artery stenoses than men.

  7. Abdominal perfusion computed tomography.

    Science.gov (United States)

    Ogul, Hayri; Bayraktutan, Ummugulsum; Kizrak, Yesim; Pirimoglu, Berhan; Yuceler, Zeynep; Sagsoz, M Erdem; Yilmaz, Omer; Aydinli, Bulent; Ozturk, Gurkan; Kantarci, Mecit

    2013-02-01

    The purpose of this article is to provide an up to date review on the spectrum of applications of perfusion computed tomography (CT) in the abdomen. New imaging techniques have been developed with the objective of obtaining a structural and functional analysis of different organs. Recently, perfusion CT has aroused the interest of many researchers who are studying the applicability of imaging modalities in the evaluation of abdominal organs and diseases. Per-fusion CT enables fast, non-invasive imaging of the tumor vascular physiology. Moreover, it can act as an in vivo biomarker of tumor-related angiogenesis.

  8. TU-G-204-01: BEST IN PHYSICS (IMAGING): Dynamic CT Myocardial Perfusion Measurement and Its Comparison to Fractional Flow Reserve

    Energy Technology Data Exchange (ETDEWEB)

    Ziemer, B; Hubbard, L; Groves, E; Sadeghi, B; Javan, H; Lipinski, J; Molloi, S [University of California, Irvine, CA (United States)

    2015-06-15

    Purpose: To evaluate a first pass analysis (FPA) technique for CT perfusion measurement in a swine animal and its validation using fractional flow reserve (FFR) as a reference standard. Methods: Swine were placed under anesthesia and relevant physiologic parameters were continuously recorded. Intra-coronary adenosine was administered to induce maximum hyperemia. A pressure wire was advanced distal to the first diagonal branch of the left anterior descending (LAD) artery for FFR measurements and a balloon dilation catheter was inserted over the pressure wire into the proximal LAD to create varying levels of stenosis. Images were acquired with a 320-row wide volume CT scanner. Three main coronary perfusion beds were delineated in the myocardium using arteries extracted from CT angiography images using a minimum energy hypothesis. The integrated density in the perfusion bed was used to calculate perfusion using the FPA technique. The perfusion in the LAD bed over a range of stenosis severity was measured. The measured fractional perfusion was compared to FFR and linear regression was performed. Results: The measured fractional perfusion using the FPA technique (P-FPA) and FFR were related as P-FPA = 1.06FFR – 0.06 (r{sup 2} = 0.86). The perfusion measurements were calculated with only three to five total CT volume scans, which drastically reduces the radiation dose as compared with the existing techniques requiring 15–20 volume scans. Conclusion: The measured perfusion using the first pass analysis technique showed good correlation with FFR measurements as a reference standard. The technique for perfusion measurement can potentially make a substantial reduction in radiation dose as compared with the existing techniques.

  9. Perfusion Angiography of the Foot in Patients with Critical Limb Ischemia: Description of the Technique

    Energy Technology Data Exchange (ETDEWEB)

    Jens, Sjoerd, E-mail: s.jens@amc.uva.nl; Marquering, Henk A., E-mail: h.a.marquering@amc.uva.nl [Academic Medical Center, Department of Radiology (Netherlands); Koelemay, Mark J. W., E-mail: m.j.koelemaij@amc.uva.nl [Academic Medical Center, Department of Surgery (Netherlands); Reekers, Jim A., E-mail: j.a.reekers@amc.uva.nl [Academic Medical Center, Department of Radiology (Netherlands)

    2015-02-15

    ObjectiveTo study the feasibility of 2D perfusion imaging in critical limb ischemia (CLI).Methods/ResultsPerfusion angiography is a new technology which was tested in 18 patients with CLI of the foot. A standardized protocol was used with a catheter placed at the mid-part of the popliteal artery, and a total of 9 cc of non-ionic iodinated contrast material was injected at a rate of 3 cc/sec. The technology is based on early cardiology research where iodinated contrast agents were used for imaging of cardiac perfusion. During the first pass of the contrast, there is a significant diffusion of the contrast agents into the interstitial space, particularly for non-ionic and low-molecular-weight compounds.DiscussionThe original angiography data can be used to make a time–density curve, which represents the actual perfusion of the foot in time. Angiographic perfusion imaging is a post-processing modality for which no extra contrast or radiation is needed. With this technique, it is possible to get more information about the perfusion status and microcirculation of the foot. This is a step toward functional imaging in CLI patients.

  10. A laser speckle imaging technique for measuring tissue perfusion.

    Science.gov (United States)

    Forrester, Kevin R; Tulip, J; Leonard, C; Stewart, C; Bray, Robert C

    2004-11-01

    Laser Doppler imaging (LDI) has become a standard method for optical measurement of tissue perfusion, but is limited by low resolution and long measurement times. We have developed an analysis technique based on a laser speckle imaging method that generates rapid, high-resolution perfusion images. We have called it laser speckle perfusion imaging (LSPI). This paper investigates LSPI output and compares it to LDI using blood flow models designed to simulate human skin at various levels of pigmentation. Results show that LSPI parameters can be chosen such that the instrumentation exhibits a similar response to changes in red blood cell concentration (0.1%-5%, 200 microL/min) and velocity (0-800 microL/min, 1% concentration) and, given its higher resolution and quicker response time, could provide a significant advantage over LDI for some applications. Differences were observed in the LDI and LSPI response to tissue optical properties. LDI perfusion values increased with increasing tissue absorption, while LSPI perfusion values showed a slight decrease. This dependence is predictable, owing to the perfusion algorithms specific to each instrument, and, if properly compensated for, should not influence each instrument's ability to measure relative changes in tissue perfusion.

  11. Perfusion Linearity and Its Applications

    CERN Document Server

    Pianykh, Oleg

    2010-01-01

    Perfusion analysis computes blood flow parameters (blood volume, blood flow, mean transit time) from the observed flow of contrast agent, passing through the patient's vascular system. Perfusion deconvolution has been widely accepted as the principal numerical tool for perfusion analysis, and is used routinely in clinical applications. This extensive use of perfusion in clinical decision-making makes numerical stability and robustness of perfusion computations vital for accurate diagnostics and patient safety. The main goal of this paper is to propose a novel approach for validating numerical properties of perfusion algorithms. The approach is based on Perfusion Linearity Property (PLP), which we find in perfusion deconvolution, as well as in many other perfusion techniques. PLP allows one to study perfusion values as weighted averages of the original imaging data. This, in turn, uncovers hidden problems with the existing deconvolution techniques, and may be used to suggest more reliable computational approac...

  12. Dutch perfusion incident survey.

    Science.gov (United States)

    Groenenberg, Ingrid; Weerwind, Patrick W; Everts, Peter A M; Maessen, Jos G

    2010-09-01

    Cardiopulmonary bypass procedures remain complex, involving many potential risks. Therefore, a nationwide retrospective study was conducted to gain insight into the number of incidents and accidents in Dutch adult perfusion practice. An anonymous postal survey (85 questions about hardware, disposables, fluids and medication, air emboli, anticoagulation, practice, and safety measures) was sent to all Dutch perfusionists involved in adult cardiovascular perfusion during 2006 and 2007. To guarantee complete anonymity, respondents were asked to return the survey to a notary who discarded personal information. The net response rate was 72% and covered 23,500 perfusions. Individual respondents performed 240 ± 103 perfusions during the 2-year study period and had 13.8 ± 8.7 years of practical experience. The incident rate was 1 per 15.6 perfusions and the adverse event rate was 1 per 1,236 perfusions. The three most reported incidents were: (1) persistent inability to raise the activated coagulation time above 400s during perfusion (184 incidents); (2) an allergic or anaphylactic reaction to drugs, fluids, or blood products (114 incidents); and (3) clotting formation in the extracorporeal circuit (74 incidents). Furthermore, pre-bypass safety measures showed no statistically significant association with the reported incidents. In comparison with data from the recent literature, the reported number of incidents is high. Nevertheless, the adverse outcome rate is well matched to other published surveys. The relatively high response rate conveys the impression that the Dutch perfusionist is vigilant and willing to report incidents. Hence, a web-based Dutch perfusion incident registration system is recommended.

  13. Assessment of differential pulmonary blood flow using perfusion magnetic resonance imaging: comparison with radionuclide perfusion scintigraphy.

    Science.gov (United States)

    Molinari, Francesco; Fink, Christian; Risse, Frank; Tuengerthal, Siegfried; Bonomo, Lorenzo; Kauczor, Hans-Ulrich

    2006-08-01

    We sought to assess the agreement between lung perfusion ratios calculated from pulmonary perfusion magnetic resonance imaging (MRI) and those calculated from radionuclide (RN) perfusion scintigraphy. A retrospective analysis of MR and RN perfusion scans was conducted in 23 patients (mean age, 60 +/- 14 years) with different lung diseases (lung cancer = 15, chronic obstructive pulmonary disease = 4, cystic fibrosis = 2, and mesothelioma = 2). Pulmonary perfusion was assessed by a time-resolved contrast-enhanced 3D gradient-echo pulse sequence using parallel imaging and view sharing (TR = 1.9 milliseconds; TE = 0.8 milliseconds; parallel imaging acceleration factor = 2; partition thickness = 4 mm; matrix = 256 x 96; in-plane spatial resolution = 1.87 x 3.75 mm; scan time for each 3D dataset = 1.5 seconds), using gadolinium-based contrast agents (injection flow rate = 5 mL/s, dose = 0.1 mmol/kg of body weight). The peak concentration (PC) of the contrast agent bolus, the pulmonary blood flow (PBF), and blood volume (PBV) were computed from the signal-time curves of the lung. Left-to-right ratios of pulmonary perfusion were calculated from the MR parameters and RN counts. The agreement between these ratios was assessed for side prevalence (sign test) and quantitatively (Deming-regression). MR and RN ratios agreed on side prevalence in 21 patients (91%) with PC, in 20 (87%) with PBF, and in 17 (74%) with PBV. The MR estimations of left-to-right perfusion ratios correlated significantly with those of RN perfusion scans (P lung. Further studies in a larger group of patients are required to fully confirm the clinical suitability of this imaging method.

  14. Low dose CT perfusion using k-means clustering

    Science.gov (United States)

    Pisana, Francesco; Henzler, Thomas; Schönberg, Stefan; Klotz, Ernst; Schmidt, Bernhard; Kachelrieß, Marc

    2016-03-01

    We aim at improving low dose CT perfusion functional parameters maps and CT images quality, preserving quantitative information. In a dynamic CT perfusion dataset, each voxel is measured T times, where T is the number of acquired time points. In this sense, we can think about a voxel as a point in a T-dimensional space, where the coordinates of the voxels would be the values of its time attenuation curve (TAC). Starting from this idea, a k-means algorithm was designed to group voxels in K classes. A modified guided time-intensity profile similarity (gTIPS) filter was implemented and applied only for those voxels belonging to the same class. The approach was tested on a digital brain perfusion phantom as well as on clinical brain and body perfusion datasets, and compared to the original TIPS implementation. The TIPS filter showed the highest CNR improvement, but lowest spatial resolution. gTIPS proved to have the best combination of spatial resolution and CNR improvement for CT images, while k-gTIPS was superior to both gTIPS and TIPS in terms of perfusion maps image quality. We demonstrate k-means clustering analysis can be applied to denoise dynamic CT perfusion data and to improve functional maps. Beside the promising results, this approach has the major benefit of being independent from the perfusion model employed for functional parameters calculation. No similar approaches were found in literature.

  15. Comparison of Myocardial Perfusion Estimates From Dynamic Contrast-Enhanced Magnetic Resonance Imaging With Four Quantitative Analysis Methods

    Science.gov (United States)

    Pack, Nathan A.; DiBella, Edward V. R.

    2012-01-01

    Dynamic contrast-enhanced MRI has been used to quantify myocardial perfusion in recent years. Published results have varied widely, possibly depending on the method used to analyze the dynamic perfusion data. Here, four quantitative analysis methods (two-compartment modeling, Fermi function modeling, model-independent analysis, and Patlak plot analysis) were implemented and compared for quantifying myocardial perfusion. Dynamic contrast-enhanced MRI data were acquired in 20 human subjects at rest with low-dose (0.019 ± 0.005 mmol/kg) bolus injections of gadolinium. Fourteen of these subjects were also imaged at adenosine stress (0.021 ± 0.005 mmol/kg). Aggregate rest perfusion estimates were not significantly different between all four analysis methods. At stress, perfusion estimates were not significantly different between two-compartment modeling, model-independent analysis, and Patlak plot analysis. Stress estimates from the Fermi model were significantly higher (~20%) than the other three methods. Myocardial perfusion reserve values were not significantly different between all four methods. Model-independent analysis resulted in the lowest model curve-fit errors. When more than just the first pass of data was analyzed, perfusion estimates from two-compartment modeling and model-independent analysis did not change significantly, unlike results from Fermi function modeling. PMID:20577976

  16. Computational Fluid Dynamics Simulations of Contrast Agent Bolus Dispersion in a Coronary Bifurcation: Impact on MRI-Based Quantification of Myocardial Perfusion

    OpenAIRE

    Regine Schmidt; Dirk Graafen; Stefan Weber; Schreiber, Laura M.

    2013-01-01

    Contrast-enhanced first-pass magnetic resonance imaging (MRI) in combination with a tracer kinetic model, for example, MMID4, can be used to determine myocardial blood flow (MBF) and myocardial perfusion reserve (MPR). Typically, the arterial input function (AIF) required for this methodology is estimated from the left ventricle (LV). Dispersion of the contrast agent bolus might occur between the LV and the myocardial tissue. Negligence of bolus dispersion could cause an error in MBF determin...

  17. Assessment of the relationship between morphological emphysema phenotype and corresponding pulmonary perfusion pattern on a segmental level

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Mark; Kauczor, Hans-Ulrich [University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Member of German Lung Research Center DZL, Translational Lung Research Center TLRC-H, Heidelberg (Germany); Ley, Sebastian [Chirurgische Klinik Dr. Rinecker, Department of Diagnostic and Interventional Radiology, Munich (Germany); Ludwig Maximilians University, Department of Clinical Radiology, Munich (Germany); Eberhardt, Ralf; Herth, Felix [Thoraxklinik University of Heidelberg, Department of Pneumology and Critical Care Medicine, Heidelberg (Germany); Member of German Lung Research Center DZL, Translational Lung Research Center TLRC-H, Heidelberg (Germany); Menezes, Ravi [University of Toronto, Medical Imaging, Toronto (Canada); Sedlaczek, Oliver [University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); German Cancer Research Center, Department of Radiology, Heidelberg (Germany); Member of German Lung Research Center DZL, Translational Lung Research Center TLRC-H, Heidelberg (Germany); Ley-Zaporozhan, Julia [University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Ludwig Maximilians University, Department of Clinical Radiology, Munich (Germany)

    2015-01-15

    Distinct morphological emphysema phenotypes were assessed by CT to show characteristic perfusion defect patterns. Forty-one patients with severe emphysema (GOLD III/IV) underwent three-dimensional high resolution computed tomography (3D-HRCT) and contrast-enhanced magnetic resonance (MR) perfusion. 3D-HRCT data was visually analyzed for emphysema phenotyping and quantification by consensus of three experts in chest-radiology. The predominant phenotype per segment was categorized as normal, centrilobular, panlobular or paraseptal. Segmental lung perfusion was visually analyzed using six patterns of pulmonary perfusion (1-normal; 2-mild homogeneous reduction in perfusion; 3-heterogeneous perfusion without focal defects; 4-heterogeneous perfusion with focal defects; 5-heterogeneous absence of perfusion; 6-homogeneous absence of perfusion), with the extent of the defect given as a percentage. 730 segments were evaluated. CT categorized 566 (78 %) as centrilobular, 159 (22 %) as panlobular and 5 (<1 %) as paraseptal with no normals. Scores with regards to MR perfusion patterns were: 1-0; 2-0; 3-28 (4 %); 4-425 (58 %); 5-169 (23 %); 6-108 (15 %). The predominant perfusion pattern matched as follows: 70 % centrilobular emphysema - heterogeneous perfusion with focal defects (score 4); 42 % panlobular - homogeneous absence of perfusion (score 5); and 43 % panlobular - heterogeneous absence of perfusion (score 6). MR pulmonary perfusion patterns correlate with the CT phenotype at a segmental level in patients with severe emphysema. (orig.)

  18. 探索提高三钠液一次检测合格率的方法%Exploration the Method of Improving the First-pass Yield of Tri-sodium Liquid

    Institute of Scientific and Technical Information of China (English)

    姚复才

    2013-01-01

    The preparation of tri-sodium liquid is an important process in the production of TCCA. A low of the first-pass yield of tri-sodium liquid will lead to the next procedure in short supply and affect the product output and economic benefit. The paper analyzes the reasons of the low first-pass yield of tri-sodium liquid, and explores the specific methods to improve it.%  配制三钠液是强氯精粉生产中的重要工序,三钠液一次检测合格率低会导致下一道工序供给不足,会影响产品产量及经济效益。文章分析了三钠液一次检测合格率低的原因,探索提高三钠液一次检测合格率的具体方法。

  19. Perfusion based cell culture chips

    DEFF Research Database (Denmark)

    Heiskanen, Arto; Emnéus, Jenny; Dufva, Martin

    2010-01-01

    Performing cell culture in miniaturized perfusion chambers gives possibilities to experiment with cells under near in vivo like conditions. In contrast to traditional batch cultures, miniaturized perfusion systems provide precise control of medium composition, long term unattended cultures and ti...

  20. Dynamic contrast-enhanced quantitative perfusion measurement of the brain using T-1-weighted MRI at 3T

    DEFF Research Database (Denmark)

    Larsson, H.B.W.; Hansen, A.E.; Berg, H.K.;

    2008-01-01

    Purpose: To develop a method for the measurement of brain perfusion based on dynamic contrast-enhanced T-1-weighted MR imaging. Materials and Methods: Dynamic imaging of the first pass of a bolus of a paramagnetic contrast agent was performed using a 3T whole-body magnet and a T-1-weighted fast...... field echo sequence. The input function was obtained from the internal carotid artery. An initial T-1 measurement was performed in order to convert the MR signal to concentration of the contrast agent. Pixelwise and region of interest (ROI)based calculation of cerebral perfusion (CBF) was performed...... inside the infarct core was, 9 mL/100g/min in one of the stroke patients. The other stroke patient had postischemic hyperperfusion and CBF was 140 mL/100g/min. Conclusion: Absolute values of brain perfusion can be obtained using dynamic contrast-enhanced MRI. These values correspond,to expected values...

  1. Extremity perfusion for sarcoma

    NARCIS (Netherlands)

    Hoekstra, Harald Joan

    2008-01-01

    For more than 50 years, the technique of extremity perfusion has been explored in the limb salvage treatment of local, recurrent, and multifocal sarcomas. The "discovery" of tumor necrosis factor-or. in combination with melphalan was a real breakthrough in the treatment of primarily irresectable ext

  2. Extremity perfusion for sarcoma

    NARCIS (Netherlands)

    Hoekstra, Harald Joan

    2008-01-01

    For more than 50 years, the technique of extremity perfusion has been explored in the limb salvage treatment of local, recurrent, and multifocal sarcomas. The "discovery" of tumor necrosis factor-or. in combination with melphalan was a real breakthrough in the treatment of primarily irresectable

  3. SUBMERGED PERFUSION BIOREACTOR

    DEFF Research Database (Denmark)

    2010-01-01

    to flow out of the body. USE - A biological device for cell culturing, enzymatic reactions or filtering of fluid (claimed). ADVANTAGE - The device has simple setup without the need of external pumping mechanisms to obtain a perfusion flow system. DETAILED DESCRIPTION - A biological device comprises a body...

  4. Automatic Characterization of Myocardial Perfusion in Contrast Enhanced MRI

    Science.gov (United States)

    Positano, Vincenzo; Santarelli, Maria Filomena; Landini, Luigi

    2003-12-01

    The use of contrast medium in cardiac MRI allows joining the high-resolution anatomical information provided by standard magnetic resonance with functional information obtained by means of the perfusion of contrast agent in myocardial tissues. The current approach to perfusion MRI characterization is the qualitative one, based on visual inspection of images. Moving to quantitative analysis requires extraction of numerical indices of myocardium perfusion by analysis of time/intensity curves related to the area of interest. The main problem in quantitative image sequence analysis is the heart movement, mainly due to patient respiration. We propose an automatic procedure based on image registration, segmentation of the myocardium, and extraction and analysis of time/intensity curves. The procedure requires a minimal user interaction, is robust with respect to the user input, and allows effective characterization of myocardial perfusion. The algorithm was tested on cardiac MR images acquired from voluntaries and in clinical routine.

  5. Dual energy CT for the assessment of lung perfusion-Correlation to scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Thieme, Sven F.; Becker, Christoph R. [Department of Clinical Radiology, Ludwig-Maximilians-University of Munich (Germany); Hacker, Marcus [Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich (Germany); Nikolaou, Konstantin; Reiser, Maximilian F. [Department of Clinical Radiology, Ludwig-Maximilians-University of Munich (Germany); Johnson, Thorsten R.C. [Department of Clinical Radiology, Ludwig-Maximilians-University of Munich (Germany)], E-mail: thorsten.johnson@med.uni-muenchen.de

    2008-12-15

    Purpose of this study was to determine the diagnostic value of dual energy CT in the assessment of pulmonary perfusion with reference to pulmonary perfusion scintigraphy. Thirteen patients received both dual energy CT (DECT) angiography (Somatom Definition, Siemens) and ventilation/perfusion scintigraphy. Median time between scans was 3 days (range, 0-90). DECT perfusion maps were generated based on the spectral properties of iodine. Two blinded observes assessed DECT angiograms, perfusion maps and scintigrams for presence and location of perfusion defects. The results were compared by patient and by segment, and diagnostic accuracy of DECT perfusion imaging was calculated regarding scintigraphy as standard of reference. Diagnostic accuracy per patient showed 75% sensitivity, 80% specificity and a negative predictive value of 66%. Sensitivity per segment amounted to 83% with 99% specificity, with 93% negative predictive value. Peripheral parts of the lungs were not completely covered by the 80 kVp detector in 85% of patients. CTA identified corresponding emboli in 66% of patients with concordant perfusion defects in DECT and scintigraphy. Dual energy CT perfusion imaging is able to display pulmonary perfusion defects with good agreement to scintigraphic findings. DECT can provide a pulmonary CT angiogram, high-resolution morphology of the lung parenchyma and perfusion information in one single exam.

  6. Non-rigid registration and KLT filter to improve SNR and CNR in GRE-EPI myocardial perfusion imaging.

    Science.gov (United States)

    Mihai, Georgeta; Ding, Yu; Xue, Hui; Chung, Yiu-Cho; Rajagopalan, Sanjay; Guehring, Jens; Simonetti, Orlando P

    2012-12-01

    The purpose of the study was to evaluate the effect of motion compensation by non-rigid registration combined with the Karhunen-Loeve Transform (KLT) filter on the signal to noise (SNR) and contrast-to-noise ratio (CNR) of hybrid gradient-echo echoplanar (GRE-EPI) first-pass myocardial perfusion imaging. Twenty one consecutive first-pass adenosine stress perfusion MR data sets interpreted positive for ischemia or infarction were processed by non-rigid Registration followed by KLT filtering. SNR and CNR were measured in abnormal and normal myocardium in unfiltered and KLT filtered images following non-rigid registration to compensate for respiratory and other motions. Image artifacts introduced by filtering in registered and nonregistered images were evaluated by two observers. There was a statistically significant increase in both SNR and CNR between normal and abnormal myocardium with KLT filtering (mean SNR increased by 62.18% ± 21.05% and mean CNR increased by 58.84% ± 18.06%; p = 0.01). Motion correction prior to KLT filtering reduced significantly the occurrence of filter induced artifacts (KLT only-artifacts in 42 out of 55 image series vs. registered plus KLT-artifacts in 3 out of 55 image series). In conclusion the combination of non- rigid registration and KLT filtering was shown to increase the SNR and CNR of GRE-EPI perfusion images. Subjective evaluation of image artifacts revealed that prior motion compensation significantly reduced the artifacts introduced by the KLT filtering process.

  7. Perfusion abnormalities in hemimegalencephaly.

    Science.gov (United States)

    Wintermark, P; Roulet-Perez, E; Maeder-Ingvar, M; Moessinger, A C; Gudinchet, F; Meuli, R

    2009-04-01

    Cerebrovascular changes are rarely discussed in patients with hemimegalencephaly. These alterations have previously been associated with epileptical activity. We report the case of a 36-week gestation neonate presenting with total right hemimegalencephaly, as demonstrated by a magnetic resonance imaging (MRI) performed in the first days of life. Perfusion-weighted imaging displayed a clear hypervascularization of the right hemisphere. Diffusion-tensor imaging showed an arrangement of white matter fibers concentrically around the ventricle on the right hemisphere. AngioMRI showed an obvious asymmetry in the size of the middle cerebral arteries, with the right middle cerebral artery being prominent. The baby was free of clinical seizures during his first week of life. An electroencephalogram at that time displayed an asymmetric background activity, but no electrical seizures. Perfusion anomalies in hemimegalencephaly may not necessarily be related to epileptical activity, but may be related to vessel alterations. (c) Georg Thieme Verlag KG Stuttgart, New York.

  8. An isolated perfused pig heart model for the development, validation and translation of novel cardiovascular magnetic resonance techniques

    Directory of Open Access Journals (Sweden)

    Perera Divaka

    2010-09-01

    Full Text Available Abstract Background Novel cardiovascular magnetic resonance (CMR techniques and imaging biomarkers are often validated in small animal models or empirically in patients. Direct translation of small animal CMR protocols to humans is rarely possible, while validation in humans is often difficult, slow and occasionally not possible due to ethical considerations. The aim of this study is to overcome these limitations by introducing an MR-compatible, free beating, blood-perfused, isolated pig heart model for the development of novel CMR methodology. Methods 6 hearts were perfused outside of the MR environment to establish preparation stability. Coronary perfusion pressure (CPP, coronary blood flow (CBF, left ventricular pressure (LVP, arterial blood gas and electrolyte composition were monitored over 4 hours. Further hearts were perfused within 3T (n = 3 and 1.5T (n = 3 clinical MR scanners, and characterised using functional (CINE, perfusion and late gadolinium enhancement (LGE imaging. Perfusion imaging was performed globally and selectively for the right (RCA and left coronary artery (LCA. In one heart the RCA perfusion territory was determined and compared to infarct size after coronary occlusion. Results All physiological parameters measured remained stable and within normal ranges. The model proved amenable to CMR at both field strengths using typical clinical acquisitions. There was good agreement between the RCA perfusion territory measured by selective first pass perfusion and LGE after coronary occlusion (37% versus 36% of the LV respectively. Conclusions This flexible model allows imaging of cardiac function in a controllable, beating, human-sized heart using clinical MR systems. It should aid further development, validation and clinical translation of novel CMR methodologies, and imaging sequences.

  9. Perfusion-related stimuli for compensatory lung growth following pneumonectomy.

    Science.gov (United States)

    Dane, D Merrill; Yilmaz, Cuneyt; Gyawali, Dipendra; Iyer, Roshni; Ravikumar, Priya; Estrera, Aaron S; Hsia, Connie C W

    2016-07-01

    Following pneumonectomy (PNX), two separate mechanical forces act on the remaining lung: parenchymal stress caused by lung expansion, and microvascular distension and shear caused by increased perfusion. We previously showed that parenchymal stress and strain explain approximately one-half of overall compensation; the remainder was presumptively attributed to perfusion-related factors. In this study, we directly tested the hypothesis that perturbation of regional pulmonary perfusion modulates post-PNX lung growth. Adult canines underwent banding of the pulmonary artery (PAB) to the left caudal (LCa) lobe, which caused a reduction in basal perfusion to LCa lobe without preventing the subsequent increase in its perfusion following right PNX while simultaneously exaggerating the post-PNX increase in perfusion to the unbanded lobes, thereby creating differential perfusion changes between banded and unbanded lobes. Control animals underwent sham pulmonary artery banding followed by right PNX. Pulmonary function, regional pulmonary perfusion, and high-resolution computed tomography of the chest were analyzed pre-PNX and 3-mo post-PNX. Terminally, the remaining lobes were fixed for detailed morphometric analysis. Results were compared with corresponding lobes in two control (Sham banding and normal unoperated) groups. PAB impaired the indices of post-PNX extravascular alveolar tissue growth by up to 50% in all remaining lobes. PAB enhanced the expected post-PNX increase in alveolar capillary formation, measured by the prevalence of double-capillary profiles, in both unbanded and banded lobes. We conclude that perfusion distribution provides major stimuli for post-PNX compensatory lung growth independent of the stimuli provided by lung expansion and parenchymal stress and strain.

  10. Investigating tumor perfusion and metabolism using multiple hyperpolarized 13C compounds: HP001, pyruvate and urea

    DEFF Research Database (Denmark)

    von Morze, Cornelius; Larson, Peder E.Z.; Hu, Simon

    2012-01-01

    ]pyruvate, with compressed sensing for resolution enhancement. For the dynamic data, peak signal maps and blood flow maps derived from perfusion modeling were generated. The spatial heterogeneity of perfusion was increased 2.9-fold in tumor tissues (P=.05), and slower washout was observed in the dynamic data. The results...

  11. High-resolution blood-pool-contrast-enhanced MR angiography in glioblastoma: tumor-associated neovascularization as a biomarker for patient survival. A preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Puig, Josep; Blasco, Gerard; Remollo, Sebastian; Hernandez, David; Pedraza, Salvador [Hospital Universitari Dr Josep Trueta, Research Unit of Diagnostic Imaging Institute (IDI), Department of Radiology [Girona Biomedical Research Institute] IDIBGI, Girona (Spain); Daunis-i-Estadella, Josep; Mateu, Gloria [University of Girona, Department of Computer Science, Applied Mathematics and Statistics, Girona (Spain); Alberich-Bayarri, Angel [La Fe Polytechnics and University Hospital, Biomedical Imaging Research Group (GIBI230), La Fe Health Research Institute, Valencia (Spain); Essig, Marco [University of Manitoba, Department of Radiology, Winnipeg (Canada); Jain, Rajan [NYU School of Medicine, Division of Neuroradiology, Department of Radiology, New York, NY (United States); Puigdemont, Montserrat [Hospital Universitari Dr Josep Trueta, Catalan Institute of Oncology (ICO), Hospital Cancer Registry, Girona (Spain); Sanchez-Gonzalez, Javier [Philips Healthcare Iberica, Madrid (Spain); Wintermark, Max [Stanford University, Department of Radiology, Neuroradiology Division, Palo Alto, CA (United States)

    2016-01-15

    The objective of the study was to determine whether tumor-associated neovascularization on high-resolution gadofosveset-enhanced magnetic resonance angiography (MRA) is a useful biomarker for predicting survival in patients with newly diagnosed glioblastomas. Before treatment, 35 patients (25 men; mean age, 64 ± 14 years) with glioblastoma underwent MRI including first-pass dynamic susceptibility contrast (DSC) perfusion and post-contrast T1WI sequences with gadobutrol (0.1 mmol/kg) and, 48 h later, high-resolution MRA with gadofosveset (0.03 mmol/kg). Volumes of interest for contrast-enhancing lesion (CEL), non-CEL, and contralateral normal-appearing white matter were obtained, and DSC perfusion and DWI parameters were evaluated. Prognostic factors were assessed by Kaplan-Meier survival and Cox proportional hazards model. Eighteen (51.42 %) glioblastomas were hypervascular on high-resolution MRA. Hypervascular glioblastomas were associated with higher CEL volume and lower Karnofsky score. Median survival rates for patients with hypovascular and hypervascular glioblastomas treated with surgery, radiotherapy, and chemotherapy were 15 and 9.75 months, respectively (P < 0.001). Tumor-associated neovascularization was the best predictor of survival at 5.25 months (AUC = 0.794, 81.2 % sensitivity, 77.8 % specificity, 76.5 % positive predictive value, 82.4 % negative predictive value) and yielded the highest hazard ratio (P < 0.001). Tumor-associated neovascularization detected on high-resolution blood-pool-contrast-enhanced MRA of newly diagnosed glioblastoma seems to be a useful biomarker that correlates with worse survival. (orig.)

  12. Perfusion Based Cell Culture Chips

    Science.gov (United States)

    Heiskanen, A.; Emnéus, J.; Dufva, M.

    Performing cell culture in miniaturized perfusion chambers gives possibilities to experiment with cells under near in vivo like conditions. In contrast to traditional batch cultures, miniaturized perfusion systems provide precise control of medium composition, long term unattended cultures and tissue like structuring of the cultures. However, as this chapter illustrates, many issues remain to be identified regarding perfusion cell culture such as design, material choice and how to use these systems before they will be widespread amongst biomedical researchers.

  13. Perfusion based cell culture chips

    DEFF Research Database (Denmark)

    Heiskanen, Arto; Emnéus, Jenny; Dufva, Martin

    2010-01-01

    and tissue like structuring of the cultures. However, as this chapter illustrates, many issues remain to be identified regarding perfusion cell culture such as design, material choice and how to use these systems before they will be widespread amongst biomedical researchers.......Performing cell culture in miniaturized perfusion chambers gives possibilities to experiment with cells under near in vivo like conditions. In contrast to traditional batch cultures, miniaturized perfusion systems provide precise control of medium composition, long term unattended cultures...

  14. Comparison of the iron oxide-based blood-pool contrast medium VSOP-C184 with gadopentetate dimeglumine for first-pass magnetic resonance angiography of the aorta and renal arteries in pigs.

    Science.gov (United States)

    Schnorr, Jörg; Wagner, Susanne; Abramjuk, Claudia; Wojner, Ines; Schink, Tania; Kroencke, Thomas J; Schellenberger, Eyk; Hamm, Bernd; Pilgrimm, Herbert; Taupitz, Matthias

    2004-09-01

    VSOP-C184 at a dose of 0.045 mmol Fe/kg has been shown to be an efficient blood pool contrast medium for equilibrium magnetic resonance angiography (MRA) that can be administered as a bolus. The present study was performed to determine whether VSOP-C184 is also suitable for first-pass MRA. Fifteen MRA examinations at 1.5 T were performed in minipigs using a fast 3D fast low-angle shot (FLASH) sequence (repetition time = 4.5 ms, echo time = 1.7 ms, excitation angle = 25 degrees, matrix 256, body phased-array coil). The citrate-stabilized iron oxide preparation VSOP-C184 was investigated (total particle diameter: 7.0 +/- 0.15 nm; core size: 4 nm) and compared with gadopentetate dimeglumine (Gd-DTPA). The following doses were tested: VSOP-C184: 0.015, 0.025, and 0.035 mmol Fe/kg; Gd-DTPA: 0.1 and 0.2 mmol Gd/kg; n = 3 examinations/dose. Data were analyzed quantitatively (signal enhancement (ENH) and vessel edge definition (VED)) and qualitatively. First-pass MRA using the 3 doses of VSOP-C184 yielded the following ENH: aorta: 9.4 +/- 2.6; 12.31 +/- 1.2; 16.53 +/- 1.7; renal arteries: 7.6 +/- 2.2; 9.9 +/- 1.0; 13.2 +/- 0.5. The values for the 2 doses of Gd-DTPA were aorta: 12.9 +/- 1.0; 16.8 +/- 2.2; renal arteries: 11.2 +/- 1.23; 11.3 +/- 1.7. VED for the 3 doses of VSOP-C184 was aorta: 106.3 +/- 31.0; 135.3 +/- 58.8; 141.3 +/- 71.0; renal arteries: 102.2 +/- 24.3; 146.8 +/- 63.0; 126.9 +/- 37.6 and for the 2 doses of Gd-DTPA, aorta: 157.2 +/- 47.8; 164.2 +/- 36.8; renal arteries: 165.9 +/- 30.4; 170.3 +/- 38.2 respectively. The differences between VSOP-C184 and Gd-DTPA are clinically not relevant and statistically not significant (p > or = .05). Qualitative evaluation of image quality, contrast, and delineation of vessels showed the results obtained with VSOP-C184 at doses of 0.025 and 0.035 mmol Fe/kg to be similar to those of Gd-DTPA at 0.1 and 0.2 mmol Gd/kg. VSOP-C184 is suitable for first-pass MRA at doses of 0.025 and 0.035 mmol Fe/kg and thus, in addition to

  15. Dynamic chest image analysis: model-based pulmonary perfusion analysis with pyramid images

    Science.gov (United States)

    Liang, Jianming; Haapanen, Arto; Jaervi, Timo; Kiuru, Aaro J.; Kormano, Martti; Svedstrom, Erkki; Virkki, Raimo

    1998-07-01

    The aim of the study 'Dynamic Chest Image Analysis' is to develop computer analysis and visualization methods for showing focal and general abnormalities of lung ventilation and perfusion based on a sequence of digital chest fluoroscopy frames collected at different phases of the respiratory/cardiac cycles in a short period of time. We have proposed a framework for ventilation study with an explicit ventilation model based on pyramid images. In this paper, we extend the framework to pulmonary perfusion study. A perfusion model and the truncated pyramid are introduced. The perfusion model aims at extracting accurate, geographic perfusion parameters, and the truncated pyramid helps in understanding perfusion at multiple resolutions and speeding up the convergence process in optimization. Three cases are included to illustrate the experimental results.

  16. Perfusion Magnetic Resonance Imaging: A Comprehensive Update on Principles and Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Jahng, Geon Ho [Dept. of Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul (Korea, Republic of); Li, Ka Loh [Wolfson Molecular Imaging Center, The University of Manchester, Manchester (United Kingdom); Ostergaard, Leif [Center for Functionally Integrative Neuroscience, Dept. of Neuroradiology, Aarhus University Hospital, Aarhus (Denmark); Calamante, Femando [Florey Institute of Neuroscience and Mental Health, Heidelberg, Victoria (Austria)

    2014-10-15

    Perfusion is a fundamental biological function that refers to the delivery of oxygen and nutrients to tissue by means of blood flow. Perfusion MRI is sensitive to microvasculature and has been applied in a wide variety of clinical applications, including the classification of tumors, identification of stroke regions, and characterization of other diseases. Perfusion MRI techniques are classified with or without using an exogenous contrast agent. Bolus methods, with injections of a contrast agent, provide better sensitivity with higher spatial resolution, and are therefore more widely used in clinical applications. However, arterial spin-labeling methods provide a unique opportunity to measure cerebral blood flow without requiring an exogenous contrast agent and have better accuracy for quantification. Importantly, MRI-based perfusion measurements are minimally invasive overall, and do not use any radiation and radioisotopes. In this review, we describe the principles and techniques of perfusion MRI. This review summarizes comprehensive updated knowledge on the physical principles and techniques of perfusion MRI.

  17. Perfusion Bioreactor Module

    Science.gov (United States)

    Morrison, Dennis R.

    1990-01-01

    Perfusion bioreactor module, self-contained, closed-loop cell-culture system that operates in microgravity or on Earth. Equipment supports growth or long-term maintenance of cultures of human or other fragile cells for experiments in basic cell biology or process technology. Designed to support proliferation (initially at exponential rates of growth) of cells in complex growth medium and to maintain confluent cells in defined medium under conditions optimized to permit or encourage selected functions of cells, including secretion of products of cells into medium.

  18. Measuring myocardial perfusion

    DEFF Research Database (Denmark)

    Qayyum, A A; Kastrup, J

    2015-01-01

    -pass of non-ionic and ionic contrast agents, respectively. Absolute quantification with CMR has yet to be established in routine clinical practice, while CT has yet to prove its diagnostic and prognostic value. The upcoming years may change the way we diagnose and treat patients suspected of having CAD......Recently, focus has changed from anatomical assessment of coronary arteries towards functional testing to evaluate the effect of stenosis on the myocardium before intervention. Besides positron-emission tomography (PET), cardiac MRI (CMR), and cardiac CT are able to measure myocardial perfusion...

  19. Noncontact blood perfusion mapping in clinical applications

    Science.gov (United States)

    Iakovlev, Dmitry; Dwyer, Vincent; Hu, Sijung; Silberschmidt, Vadim

    2016-04-01

    Non-contact imaging photoplethysmography (iPPG) to detect pulsatile blood microcirculation in tissue has been selected as a successor to low spatial resolution and slow scanning blood perfusion techniques currently employed by clinicians. The proposed iPPG system employs a novel illumination source constructed of multiple high power LEDs with narrow spectral emission, which are temporally modulated and synchronised with a high performance sCMOS sensor. To ensure spectrum stability and prevent thermal wavelength drift due to junction temperature variations, each LED features a custom-designed thermal management system to effectively dissipate generated heat and auto-adjust current flow. The use of a multi-wavelength approach has resulted in simultaneous microvascular perfusion monitoring at various tissue depths, which is an added benefit for specific clinical applications. A synchronous detection algorithm to extract weak photoplethysmographic pulse-waveforms demonstrated robustness and high efficiency when applied to even small regions of 5 mm2. The experimental results showed evidences that the proposed system could achieve noticeable accuracy in blood perfusion monitoring by creating complex amplitude and phase maps for the tissue under examination.

  20. Myocardial perfusion modeling using MRI

    DEFF Research Database (Denmark)

    Larsson, H B; Fritz-Hansen, T; Rostrup, Egill

    1996-01-01

    In the present study, it is shown that it is possible to quantify myocardial perfusion using magnetic resonance imaging in combination with gadolinium diethylenetriaminopentaacetic acid (Gd-DTPA). Previously, a simple model and method for measuring myocardial perfusion using an inversion recovery...

  1. Myocardial perfusion modeling using MRI

    DEFF Research Database (Denmark)

    Larsson, H B; Fritz-Hansen, T; Rostrup, Egill

    1996-01-01

    In the present study, it is shown that it is possible to quantify myocardial perfusion using magnetic resonance imaging in combination with gadolinium diethylenetriaminopentaacetic acid (Gd-DTPA). Previously, a simple model and method for measuring myocardial perfusion using an inversion recovery...

  2. Evaluation of stenosis degree of the middle cerebral artery with high-resolution MRI and brian blood supply with MR perfusion weighted imaging%高分辨率MRI评价大脑中动脉狭窄程度与灌注加权成像评估脑供血的研究

    Institute of Scientific and Technical Information of China (English)

    崔恒; 程敬亮; 张勇

    2012-01-01

    Objective To study the value of high-resolution MRI(HRMRI) and MR perfusion weighted imaging(PWI) in evaluating the middle cerebral artery (MCA) stenosis degree and the brian blood supply. Methods PWI was performed in 30 patients with unilateral stenosis of MCA was diagnosed by HRMRI. The cerebral perfusion parameters including regional cerebral blood volume (rCBV) .regional cerebral blood flow(rCBF) .regional mean transit time(rMTT) and regional time to peak(rTTP) of the both cerebral hemispheres were quantitatively analysed. Results Among 30 patients, the MCA stenosis diagnosed by HRMRI as mild in 7, moderate in 9 and severe or acclusion in 14,respectively. Abnormal perfusion presented in all cases. The perfusion parameters (rCBF, rMTT and rTTP) had statistical significance. Between the rate of MCA moderate stenosis, severe stenosis or occlusion and the increase rate of rMTT showed a positive correlation(r=0. 897 and 0. 829 respectively,P<0. 01). Conclusion There is significantly value in evaluation of the MCA stenosis degree by HRMRI, which in combination with PWI to assess brain blood supply is of important value for clinic.%目的 探讨高分辨率MRI(high-resolution MRI,HRMRI)判定大脑中动脉(middle cerebral artery,MCA)狭窄程度与脑MRI灌注加权成像(perfusion weighted imaging,PWI)评价脑供血的价值.方法 对30例短暂性脑缺血(TIA)患者行HRMRI以判定单侧MCA狭窄程度,并行MRI PWI检查,得出患侧和镜像侧灌注参数,包括相对脑血容量(relative cerebral blood volume,rCBV)、相对脑血流量(relative cerebral blood flow,rBCF)、相对平均通过时间(relative mean transit time,rMTT)、相对达峰时间(relative time to peak,rTTP),并对其进行定量分析.结果 30例患者中,HRMRI判定MCA轻度狭窄7例,中度狭窄9例,重度狭窄或闭塞14例;30例灌注均出现异常,rCBF、rMTT、rTTP灌注参数均具有统计学意义,其中MCA中度、重度狭窄或闭塞组狭窄率与r

  3. Congenital heart disease in adults: Quantitative and qualitative evaluation of IR FLASH and IR SSFP MRA techniques using a blood pool contrast agent in the steady state and comparison to first pass MRA.

    Science.gov (United States)

    Febbo, Jennifer A; Galizia, Mauricio S; Murphy, Ian G; Popescu, Andrada; Bi, Xiaoming; Turin, Alexander; Collins, Jeremy; Markl, Michael; Edelman, Robert R; Carr, James C

    2015-10-01

    To evaluate magnetic resonance angiography sequences during the contrast steady-state (SS-MRA) using inversion recovery (IR) with fast low-angle shot (IR-FLASH) or steady-state free precession (IR-SSFP) read-outs, following the injection of a blood-pool contrast agent, and compare them to first-pass MR angiography (FP-MRA) in adults with congenital heart disease (CHD). Twenty-three adult patients with CHD who underwent both SS-MRA and FP-MRA using a 1.5-T scanner were retrospectively identified. Signal-to-noise and contrast-to-noise ratios were obtained at eight locations within the aorta and pulmonary vessels.. Image quality and the presence of artifacts were subjectively assessed by two radiologists. The presence of pathology was noted and given a confidence score. There was no difference in vessel dimensions among the sequences. IR-SSFP showed better image quality and fewer artifacts than IR-FLASH and FP-MRA. Confidence scores were significantly higher for SS-MRA compared to FP-MRA. Seven cases (30.4%) had findings detected at SS-MRA that were not detected at FP-MRA, and 2 cases (8.7%) had findings detected by IR-SSFP only. SS-MRA of the thoracic vasculature using a blood pool contrast agent offers superior image quality and reveals more abnormalities compared to standard FP-MRA in adults with CHD, and it is best achieved with an IR-SSFP sequence. These sequences could lead to increased detection rates of abnormalities and provide a simpler protocol image acquisition. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. Perfusion measurement in acute pancreatitis using dynamic perfusion MDCT.

    Science.gov (United States)

    Bize, Pierre E; Platon, Alexandra; Becker, Christoph D; Poletti, Pierre-Alexandre

    2006-01-01

    Our objective was to determine whether MDCT with perfusion imaging could help in assessing the severity of acute pancreatitis in the initial phase of the disease. One hundred six patients with abdominal pain were prospectively enrolled in this study. Patients were separated into two groups: P1 (severe) and P2 (mild) acute pancreatitis. Mean perfusion value was 24.8 mL/100 mL/min in the P1 group and 50.5 mL/100 mL/min in the P2 group (p = 0.0016, significant). Our preliminary data suggest that pancreatic perfusion measurement using MDCT with perfusion imaging could help in assessing the severity of acute pancreatitis.

  5. Placental perfusion - a human alternative

    DEFF Research Database (Denmark)

    Mose, Tina; Knudsen, Lisbeth E

    2006-01-01

    Foetal exposures to environmental and medicinal products have impact on the growth of the foetus (e.g. cigarette smoke) and development of organs (e.g. methylmercury and Thalidomide). Perfusion studies of the human term placenta enable investigation of placental transport of chemical substances...... between the mother and foetus. Dual perfusion of a single cotyledon in the human placenta can contribute to a better understanding of the placental barrier, transport rate and mechanisms of different substances and placental metabolism. The perfusion system has recently been established in Copenhagen...

  6. CT perfusion imaging in the management of posterior reversible encephalopathy

    Energy Technology Data Exchange (ETDEWEB)

    Casey, S.O.; McKinney, A.; Teksam, M.; Liu, H.; Truwit, C.L. [Department of Radiology, University of Minnesota Medical School, 420 Delaware Street SE, Box 292, MN 55455, Minneapolis (United States)

    2004-04-01

    A 13-year-old girl with a renal transplant presented with hypertension and seizures. CT and MRI demonstrated typical bilateral parietal, occipital and posterior frontal cortical and subcortical edema, thought to represent posterior reversible encephalopathy syndrome. The cause was presumed to be hypertension. Antihypertensive therapy was started, lowering of the blood pressure in the range of 110-120 mmHg systolic. However, stable xenon (Xe) CT perfusion imaging revealed ischemia within the left parietal occipital region. The antihypertensive was adjusted which increased both the systolic and diastolic blood pressure by 31 mm Hg. The patient was re-imaged with Xe CT and was found to have resolution of the ischemic changes within the left parietal occipital region. In this report, we present a case in which stable Xe CT was used to monitor the degree of cerebral perfusion and guide titration of antihypertensive therapy. Such brain perfusion monitoring may have helped to prevent infarction of our patient. (orig.)

  7. Comparison of partial volume effects in arterial and venous contrast curves in CT brain perfusion imaging.

    Directory of Open Access Journals (Sweden)

    Alan J Riordan

    Full Text Available PURPOSE: In brain CT perfusion (CTP, the arterial contrast bolus is scaled to have the same area under the curve (AUC as the venous outflow to correct for partial volume effects (PVE. This scaling is based on the assumption that large veins are unaffected by PVE. Measurement of the internal carotid artery (ICA, usually unaffected by PVE due to its large diameter, may avoid the need for partial volume correction. The aims of this work are to examine i the assumptions behind PVE correction and ii the potential of selecting the ICA obviating correction for PVE. METHODS: The AUC of the ICA and sagittal sinus were measured in CTP datasets from 52 patients. The AUCs were determined by i using commercial CTP software based on a Gaussian curve-fitting to the time attenuation curve, and ii by simple integration of the time attenuation curve over a time interval. In addition, frames acquired up to 3 minutes after first bolus passage were used to examine the ratio of arterial and venous enhancement. The impact of selecting the ICA without PVE correction was illustrated by reporting cerebral blood volume (CBV measurements. RESULTS: In 49 of 52 patients, the AUC of the ICA was significantly larger than that of the sagittal sinus (p = 0.017. Measured after the first pass bolus, contrast enhancement remained 50% higher in the ICA just after the first pass bolus, and 30% higher 3 minutes later. CBV measurements were significantly lowered when the ICA was used without PVE correction. CONCLUSIONS: Contradicting the assumptions underlying PVE correction, contrast in the ICA was significantly higher than in the sagittal sinus, even 3 minutes after the first pass of the contrast bolus. PVE correction might lead to overestimation of CBV if the CBV is calculated using the AUC of the time attenuation curves.

  8. Qualitative and semi-quantitative evaluation of myocardium perfusion with 3 T stress cardiac MRI.

    Science.gov (United States)

    Yun, Chun-Ho; Tsai, Jui-Peng; Tsai, Cheng-Ting; Mok, Greta S P; Sun, Jing-Yi; Hung, Chung-Lieh; Wu, Tung-Hsin; Huang, Wu-Ta; Yang, Fei-Shih; Lee, Jason Jeun-Shenn; Cury, Ricardo C; Fares, Anas; Nshisso, Lemba Dina; Bezerra, Hiram G

    2015-12-07

    3 T MRI has been adopted by some centers as the primary choice for assessment of myocardial perfusion over conventional 1.5 T MRI. However, there is no data published on the potential additional value of incorporating semi-quantitative data from 3 T MRI. This study sought to determine the performance of qualitative 3 T stress magnetic resonance myocardial perfusion imaging (3 T-MRMPI) and the potential incremental benefit of using a semi-quantitative perfusion technique in patients with suspected coronary artery disease (CAD). Fifty eight patients (41 men; mean age: 59 years) referred for elective diagnostic angiography underwent stress 3 T MRMPI with a 32-channel cardiac receiver coil. The MR protocol included gadolinium-enhanced stress first-pass perfusion (0.56 mg/kg, dipyridamole), rest perfusion, and delayed enhancement (DE). Visual analysis was performed in two steps. Ischemia was defined as a territory with perfusion defect at stress study but no DE or a territory with DE but additional peri-infarcted perfusion defect at stress study. Semi-quantitative analysis was calculated by using the upslope of the signal intensity-time curve during the first pass of contrast medium during dipyridamole stress and at rest. ROC analysis was used to determine the MPRI threshold that maximized sensitivity. Quantitative coronary angiography served as the reference standard with significant stenosis defined as >70 % diameter stenosis. Diagnostic performance was determined on a per-patient and per-vessel basis. Qualitative assessment had an overall sensitivity and specificity for detecting significant stenoses of 77 % and 80 %, respectively. By adding MPRI analysis, in cases with negative qualitative assessment, the overall sensitivity increased to 83 %. The impact of MPRI differed depending on the territory; with the sensitivity for detection of left circumflex (LCx) stenosis improving the most after semi-quantification analysis, (66 % versus 83 %). Pure

  9. High-frequency Electrocardiogram Analysis in the Ability to Predict Reversible Perfusion Defects during Adenosine Myocardial Perfusion Imaging

    Science.gov (United States)

    Tragardh, Elin; Schlegel, Todd T.; Carlsson, Marcus; Pettersson, Jonas; Nilsson, Klas; Pahlm, Olle

    2007-01-01

    Background: A previous study has shown that analysis of high-frequency QRS components (HF-QRS) is highly sensitive and reasonably specific for detecting reversible perfusion defects on myocardial perfusion imaging (MPI) scans during adenosine. The purpose of the present study was to try to reproduce those findings. Methods: 12-lead high-resolution electrocardiogram recordings were obtained from 100 patients before (baseline) and during adenosine Tc-99m-tetrofosmin MPI tests. HF-QRS were analyzed regarding morphology and changes in root mean square (RMS) voltages from before the adenosine infusion to peak infusion. Results: The best area under the curve (AUC) was found in supine patients (AUC=0.736) in a combination of morphology and RMS changes. None of the measurements, however, were statistically better than tossing a coin (AUC=0.5). Conclusion: Analysis of HF-QRS was not significantly better than tossing a coin for determining reversible perfusion defects on MPI scans.

  10. Laser Doppler perfusion monitoring and imaging of blood microcirculation

    Science.gov (United States)

    Nilsson, Gert E.; Wardell, Karin

    1994-07-01

    Laser Doppler perfusion monitoring is a method of assessing tissue perfusion based on measurements performed using Doppler broadening of monochromatic light scattered in moving blood cells. Ever since laser Doppler perfusion monitors became available about 15 years ago they have been used in numerous applications in both clinical and laboratory settings. The high spatial resolution has in practice manifested itself as one of the main limitations of the method. The reason for this is the difficulty in attaining reproducible values at successive measurement sites because most skin tissue possesses a substantial variation in blood flow even at adjacent measurement sites. In order to overcome this difficulty the laser Doppler perfusion imager was developed. In this camera-like device, the laser beam successively scans the tissue and the Doppler components of the backscattered light are detected by a remote photodiode. After a scanning procedure is complete, a color-coded perfusion map showing the spatial variation of skin blood flow is displayed on a monitor. The operating principle and early applications of this emerging technology are addressed in further detail.

  11. Multi-detector CT perfusion

    Directory of Open Access Journals (Sweden)

    Ashraf M. Enite

    2016-09-01

    Conclusion: CTP is a promising non-invasive technique assessing the efficacy, predicting early response to local treatment therapies and monitoring tumor recurrence. It assesses the degree of post therapy tumor perfusion especially the degree of arterialization.

  12. Ocular perfusion pressure in glaucoma.

    Science.gov (United States)

    Costa, Vital P; Harris, Alon; Anderson, Douglas; Stodtmeister, Richard; Cremasco, Fernanda; Kergoat, Helene; Lovasik, John; Stalmans, Ingborg; Zeitz, Oliver; Lanzl, Ines; Gugleta, Konstantin; Schmetterer, Leopold

    2014-06-01

    This review article discusses the relationship between ocular perfusion pressure and glaucoma, including its definition, factors that influence its calculation and epidemiological studies investigating the influence of ocular perfusion pressure on the prevalence, incidence and progression of glaucoma. We also list the possible mechanisms behind this association, and discuss whether it is secondary to changes in intraocular pressure, blood pressure or both. Finally, we describe the circadian variation of ocular perfusion pressure and the effects of systemic and topical medications on it. We believe that the balance between IOP and BP, influenced by the autoregulatory capacity of the eye, is part of what determines whether an individual will develop optic nerve damage. However, prospective, longitudinal studies are needed to better define the role of ocular perfusion pressure in the development and progression of glaucoma.

  13. Three-dimensional optical micro-angiography maps directional blood perfusion deep within microcirculation tissue beds in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ruikang K [Department of Biomedical Engineering, Oregon Health and Science University, Portland, OR 97237 (United States)

    2007-12-07

    Optical micro-angiography (OMAG) is a recently developed method of imaging localized blood perfusion at capillary level resolution within microcirculatory beds. This paper reports that the OMAG is capable of directional blood perfusion mapping in vivo. This is achieved simply by translating the mirror located in the reference arm back and forth while 3D imaging is performed. The mirror which moves toward the incident beam gives the blood perfusion that flows away from the beam direction and vice versa. The approach is experimentally demonstrated by imaging of a flow phantom and then cerebro-vascular perfusion of a live mouse with cranium intact.

  14. Perfusion MRI abnormalities in the absence of diffusion changes in a case of moyamoya-like syndrome in neurofibromatosis type 1

    Energy Technology Data Exchange (ETDEWEB)

    El-Koussy, Marwan; Kiefer, Claus; Schroth, Gerhard [Department of Neuroradiology, University of Bern, Inselspital, Freiburgstrasse 4, 3010 Bern (Switzerland); Loevblad, Karl-Olof [Department of Neuroradiology, University of Bern, Inselspital, Freiburgstrasse 4, 3010 Bern (Switzerland); Neuroradiology, Service de Radiodiagnostic, Hopital Cantonal Universitaire HUG, 24 rue Micheli-du-Crest, 1211 Geneva 11 (Switzerland); Steinlin, Maja [Department of Neuropediatrics, University of Bern, Inselspital, Freiburgstrasse 4, 3010 Bern (Switzerland)

    2002-11-01

    We report on a 12-year-old boy with neurofibromatosis type 1 who suffered a transient ischemic attack. Angiography revealed occlusion of intracranial arteries, moyamoya vessels and leptomeningeal collaterals. The conventional T2-weighted and the diffusion-weighted MRI images demonstrated no pathology. Dynamic first-pass postgadolinium T2* perfusion-weighted MRI depicted altered hemodynamics in the vascular territory of the left middle cerebral artery, which defined this region as ischemic tissue at risk. The patient suffered a repeat transient ischemic attack5 days later. (orig.)

  15. New method for 3D parametric visualization of contrast-enhanced pulmonary perfusion MRI data

    Energy Technology Data Exchange (ETDEWEB)

    Kuder, Tristan A.; Eichinger, Monika; Ley, Sebastian; Puderbach, Michael; Kauczor, Hans-Ulrich [Deutsches Krebsforschungszentrum, Department of Radiology, E010, Heidelberg (Germany); Risse, Frank [Deutsches Krebsforschungszentrum, Department of Medical Physics in Radiology, Heidelberg (Germany); Fink, Christian [Deutsches Krebsforschungszentrum, Department of Radiology, E010, Heidelberg (Germany); Medical Faculty Mannheim - University of Heidelberg, Department of Clinical Radiology, University Hospital Mannheim, Mannheim (Germany)

    2008-02-15

    Three-dimensional (3D) dynamic contrast-enhanced magnetic resonance imaging (3D DCE-MRI) has been proposed for the assessment of regional perfusion. The aim of this work was the implementation of an algorithm for a 3D parametric visualization of lung perfusion using different cutting planes and volume rendering. Our implementation was based on 3D DCE-MRI data of the lungs of five patients and five healthy volunteers. Using the indicator dilution theory, the regional perfusion parameters, tissue blood flow, blood volume and mean transit time were calculated. Due to the required temporal resolution, the volume elements of dynamic MR data sets show a reduced spatial resolution in the z-direction. Therefore, perfusion parameter volumes were interpolated. Linear interpolation and a combination of linear and nearest-neighbor interpolation were evaluated. Additionally, ray tracing was applied for 3D visualization. The linear interpolation algorithm caused interpolation errors at the lung borders. Using the combined interpolation, visualization of perfusion information in arbitrary cutting planes and in 3D using volume rendering was possible. This facilitated the localization of perfusion deficits compared with the coronal orientated source data. The 3D visualization of perfusion parameters using a combined interpolation algorithm is feasible. Further studies are required to evaluate the additional benefit from the 3D visualization. (orig.)

  16. 2014年世锦赛中国女排一传与防守效果统计分析%Statistical Analysis of the 2014 World Championships China Women's Volleyball Team First Pass and Defensive Effect

    Institute of Scientific and Technical Information of China (English)

    陈小雨; 张建文

    2015-01-01

    运用录像统计法、比较分析法等研究方法,在对2014世锦赛中国女排13场比赛的一传与防守技术效果进行统计的基础上,重点对中国队与美国队、意大利队、巴西队、日本队及多米尼加队的一传与防守效果统计的数据进行了对比分析研究。结果显示:一传效果方面。一传到位率相比,中国队比日本队和意大利队低;比美国队和多米尼加队高;和巴西队相差不大,排名第3。一传失误率相比,中国队比日本队、巴西队、美国队和意大利队高;比多米尼加队低,排名第5。防守效果方面。防起能攻率,中国队比美国队、巴西队和日本队低;比多米尼加队和意大利高。排名第4防守。垫失率,中国队比日本队、意大利队、巴西队和多米尼加队高;比美国队低。排名第5。建议:中国女排在一传上应改进一传技术动作、接发球站位和阵型。在防守上要加强防守阵型和配合方面的练习。%Using video statistics, comparative analysis and other research methods, in the 2014 World Championship, the Chinese women's volleyball team 13 games - and defence effect of statistics based, focusing on the Chinese team and the American team, Italy, Brazil, the Japanese team and the Dominican Republic Pass and the defensive effect of the statistical data were Analysis: a comparative study. The results show: first pass effect. A pass rate is compared, the Chinese team is lower than the Japanese team and the Italian team; higher than the American team and the Dominican Republic; and Brazil have little difference, ranking the third. A mistake rate compared to, the Chinese team than the Japanese team, Brazilian team and Italian team USA and team high; is lower than that of the Dominican Republic, ranking No.5. Defensive effects. Anti - to attack rate, China team than the USA team, the Brazil team and the Japanese team low than the Dominican Republic and Italy

  17. Role of Perfusion at Rest in the Diagnosis of Myocardial Infarction Using Vasodilator Stress Cardiovascular Magnetic Resonance.

    Science.gov (United States)

    Patel, Mita B; Mor-Avi, Victor; Kawaji, Keigo; Nathan, Sandeep; Kramer, Christopher M; Lang, Roberto M; Patel, Amit R

    2016-04-01

    In clinical practice, perfusion at rest in vasodilator stress single-photon emission computed tomography is commonly used to confirm myocardial infarction (MI) and ischemia and to rule out artifacts. It is unclear whether perfusion at rest carries similar information in cardiovascular magnetic resonance (CMR). We sought to determine whether chronic MI is associated with abnormal perfusion at rest on CMR. We compared areas of infarct and remote myocardium in 31 patients who underwent vasodilator stress CMR (1.5 T), had MI confirmed by late gadolinium enhancement (LGE scar), and coronary angiography within 6 months. Stress perfusion imaging during gadolinium first pass was followed by reversal with aminophylline (75 to 125 mg), rest perfusion, and LGE imaging. Resting and peak-stress time-intensity curves were used to obtain maximal upslopes (normalized by blood pool upslopes), which were compared between infarcted and remote myocardial regions of interest. At rest, there was no significant difference between the slopes in the regions of interest supplied by arteries with and without stenosis >70% (0.31 ± 0.16 vs 0.26 ± 0.15 1/s), irrespective of LGE scar. However, at peak stress, we found significant differences (0.20 ± 0.11 vs 0.30 ± 0.22 1/s; p rest, there was no difference between infarcted and remote myocardium (0.27 ± 0.14 vs 0.30 ± 0.17 1/s), irrespective of stenosis, but significant differences were seen during stress (0.21 ± 0.16 vs 0.28 ± 0.18 1/s; p rest associated with chronic MI are not reliably detectable on CMR images. Accordingly, unlike single-photon emission computed tomography, normal CMR perfusion at rest should not be used to rule out chronic MI.

  18. Magnetic resonance imaging of luxury perfusion of the optic nerve head in anterior ischemic optic neuropathy.

    Science.gov (United States)

    Yovel, Oren S; Katz, Miriam; Leiba, Hana

    2012-09-01

    A 49-year-old woman with painless reduction in visual acuity in her left eye was found to have nonarteritic anterior ischemic optic neuropathy (NAION). Fluorescein angiography revealed optic disc capillary leakage consistent with "luxury perfusion." Contrast-enhanced FLAIR magnetic resonance imaging (MRI) showed marked enhancement of the left optic disc. Resolution of the optic disc edema and the MRI abnormalities followed a similar time course. This report appears unique in documenting the MRI findings of luxury perfusion in NAION.

  19. Unusual ventilation perfusion scintigram in a case of immunologic pulmonary edema clinically simulating pulmonary embolism

    Energy Technology Data Exchange (ETDEWEB)

    Campeau, R.J.; Faust, J.M.; Ahmad, S.

    1987-11-01

    A case of immunologic pulmonary edema secondary to hydrochlorothiazide allergy developed in a 55-year-old woman that clinically simulated pulmonary embolism. The patient had abnormal washin images with normal washout images on an Xe-133 ventilation study. On the perfusion study, large bilateral central and posterior perfusion defects were present that showed an unusual mirror image pattern on the lateral and posterior oblique views. Resolution of radiographic and scintigraphic abnormalities occurred over a 3-day period in conjunction with corticosteroid therapy.

  20. Influence of Thin Slice Reconstruction on CT Brain Perfusion Analysis.

    Directory of Open Access Journals (Sweden)

    Edwin Bennink

    Full Text Available Although CT scanners generally allow dynamic acquisition of thin slices (1 mm, thick slice (≥5 mm reconstruction is commonly used for stroke imaging to reduce data, processing time, and noise level. Thin slice CT perfusion (CTP reconstruction may suffer less from partial volume effects, and thus yield more accurate quantitative results with increased resolution. Before thin slice protocols are to be introduced clinically, it needs to be ensured that this does not affect overall CTP constancy. We studied the influence of thin slice reconstruction on average perfusion values by comparing it with standard thick slice reconstruction.From 50 patient studies, absolute and relative hemisphere averaged estimates of cerebral blood volume (CBV, cerebral blood flow (CBF, mean transit time (MTT, and permeability-surface area product (PS were analyzed using 0.8, 2.4, 4.8, and 9.6 mm slice reconstructions. Specifically, the influence of Gaussian and bilateral filtering, the arterial input function (AIF, and motion correction on the perfusion values was investigated.Bilateral filtering gave noise levels comparable to isotropic Gaussian filtering, with less partial volume effects. Absolute CBF, CBV and PS were 22%, 14% and 46% lower with 0.8 mm than with 4.8 mm slices. If the AIF and motion correction were based on thin slices prior to reconstruction of thicker slices, these differences reduced to 3%, 4% and 3%. The effect of slice thickness on relative values was very small.This study shows that thin slice reconstruction for CTP with unaltered acquisition protocol gives relative perfusion values without clinically relevant bias. It does however affect absolute perfusion values, of which CBF and CBV are most sensitive. Partial volume effects in large arteries and veins lead to overestimation of these values. The effects of reconstruction slice thickness should be taken into account when absolute perfusion values are used for clinical decision making.

  1. Cell therapy in reperfused acute myocardial infarction does not improve the recovery of perfusion in the infarcted myocardium: a cardiac MR imaging study.

    Science.gov (United States)

    Robbers, Lourens F H J; Nijveldt, Robin; Beek, Aernout M; Hirsch, Alexander; van der Laan, Anja M; Delewi, Ronak; van der Vleuten, Pieter A; Tio, René A; Tijssen, Jan G P; Hofman, Mark B M; Piek, Jan J; Zijlstra, Felix; van Rossum, Albert C

    2014-07-01

    To investigate the effects of cell therapy on myocardial perfusion recovery after treatment of acute myocardial infarction (MI) with primary percutaneous coronary intervention (PCI). In this HEBE trial substudy, which was approved by the institutional review board (trial registry number ISRCTN95796863), the authors assessed the effects of intracoronary infusion with bone marrow-derived mononuclear cells (BMMCs) or peripheral blood-derived mononuclear cells (PBMCs) on myocardial perfusion recovery by using cardiac magnetic resonance (MR) imaging after revascularization. In 152 patients with acute MI treated with PCI, cardiac MR imaging was performed after obtaining informed consent-before randomization to BMMC, PBMC, or standard therapy (control group)-and repeated at 4-month follow-up. Cardiac MR imaging consisted of cine, rest first-pass perfusion, and late gadolinium enhancement imaging. Perfusion was evaluated semiquantitatively with signal intensity-time curves by calculating the relative upslope (percentage signal intensity change). The relative upslope was calculated for the MI core, adjacent border zone, and remote myocardium. Perfusion differences among treatment groups or between baseline and follow-up were assessed with the Wilcoxon signed rank or Mann-Whitney U test. At baseline, myocardial perfusion differed between the MI core (median, 6.0%; interquartile range [IQR], 4.1%-8.0%), border zone (median, 8.4%; IQR, 6.4%-10.2%), and remote myocardium (median, 12.2%; IQR, 10.5%-15.9%) (P < .001 for all), with equal distribution among treatment groups. These interregional differences persisted at follow-up (P < .001 for all). No difference in perfusion recovery was found between the three treatment groups for any region. After revascularization of ST-elevation MI, cell therapy does not augment the recovery of resting perfusion in either the MI core or border zone. © RSNA, 2014.

  2. Measuring perfusion with light (Conference Presentation)

    Science.gov (United States)

    Jansen, Sanne M. A.; de Bruin, Daniel M.; Faber, Dirk J.; van Leeuwen, Ton G.

    2016-03-01

    There is no gold standard test for perfusion evaluation in surgery. Optical Imaging techniques are able to image tissue at high resolution and in real-time. Laser Speckle Contrast Imaging, Optical Coherence Tomography, Sidestream Darkfield and Incident Darkfield all use the interaction of light with tissue to create an image. To test their feasibility and explore validity in a controlled setting, we created a phantom with the optical properties of tissue and microvascular channels of 30-400 micrometer. With a Hamilton Syringe Pump we mimicked blood flow velocities of 0-20 mm/sec. Images of all different modalities at different blood flow velocities were compared in terms of imaging depth, resoluation and hemodynamic parameters.

  3. Hyperventilation, cerebral perfusion, and syncope

    DEFF Research Database (Denmark)

    Immink, R V; Pott, F C; Secher, N H

    2014-01-01

    the contribution of a low PaCO2 to the early postural reduction in middle cerebral artery blood velocity is transient. HV together with postural stress does not reduce cerebral perfusion to such an extent that TLOC develops. However when HV is combined with cardiovascular stressors like cold immersion or reduced......This review summarizes evidence in humans for an association between hyperventilation (HV)-induced hypocapnia and a reduction in cerebral perfusion leading to syncope defined as transient loss of consciousness (TLOC). The cerebral vasculature is sensitive to changes in both the arterial carbon...

  4. Dynamic CT myocardial perfusion imaging.

    Science.gov (United States)

    Caruso, Damiano; Eid, Marwen; Schoepf, U Joseph; Jin, Kwang Nam; Varga-Szemes, Akos; Tesche, Christian; Mangold, Stefanie; Spandorfer, Adam; Laghi, Andrea; De Cecco, Carlo N

    2016-10-01

    Non-invasive cardiac imaging has rapidly evolved during the last decade due to advancements in CT based technologies. Coronary CT angiography has been shown to reliably assess coronary anatomy and detect high risk coronary artery disease. However, this technique is limited to anatomical assessment, thus non-invasive techniques for functional assessment of the heart are necessary. CT myocardial perfusion is a new CT based technique that provides functional assessment of the myocardium and allows for a comprehensive assessment of coronary artery disease with a single modality when combined with CTA. This review aims to discuss dynamic CT myocardial perfusion as a new technique in the assessment of CAD.

  5. Noninvasive methods of measuring bone blood perfusion

    OpenAIRE

    Dyke, J. P.; Aaron, R.K.

    2010-01-01

    Measurement of bone blood flow and perfusion characteristics in a noninvasive and serial manner would be advantageous in assessing revascularization after trauma and the possible risk of avascular necrosis. Many disease states, including osteoporosis, osteoarthritis, and bone neoplasms, result in disturbed bone perfusion. A causal link between bone perfusion and remodeling has shown its importance in sustained healing and regrowth following injury. Measurement of perfusion and permeability wi...

  6. Localized spatio-temporal constraints for accelerated CMR perfusion.

    Science.gov (United States)

    Akçakaya, Mehmet; Basha, Tamer A; Pflugi, Silvio; Foppa, Murilo; Kissinger, Kraig V; Hauser, Thomas H; Nezafat, Reza

    2014-09-01

    To develop and evaluate an image reconstruction technique for cardiac MRI (CMR) perfusion that uses localized spatio-temporal constraints. CMR perfusion plays an important role in detecting myocardial ischemia in patients with coronary artery disease. Breath-hold k-t-based image acceleration techniques are typically used in CMR perfusion for superior spatial/temporal resolution and improved coverage. In this study, we propose a novel compressed sensing-based image reconstruction technique for CMR perfusion, with applicability to free-breathing examinations. This technique uses local spatio-temporal constraints by regularizing image patches across a small number of dynamics. The technique was compared with conventional dynamic-by-dynamic reconstruction, and sparsity regularization using a temporal principal-component (pc) basis, as well as zero-filled data in multislice two-dimensional (2D) and three-dimensional (3D) CMR perfusion. Qualitative image scores were used (1 = poor, 4 = excellent) to evaluate the technique in 3D perfusion in 10 patients and five healthy subjects. On four healthy subjects, the proposed technique was also compared with a breath-hold multislice 2D acquisition with parallel imaging in terms of signal intensity curves. The proposed technique produced images that were superior in terms of spatial and temporal blurring compared with the other techniques, even in free-breathing datasets. The image scores indicated a significant improvement compared with other techniques in 3D perfusion (x-pc regularization, 2.8 ± 0.5 versus 2.3 ± 0.5; dynamic-by-dynamic, 1.7 ± 0.5; zero-filled, 1.1 ± 0.2). Signal intensity curves indicate similar dynamics of uptake between the proposed method with 3D acquisition and the breath-hold multislice 2D acquisition with parallel imaging. The proposed reconstruction uses sparsity regularization based on localized information in both spatial and temporal domains for highly accelerated CMR perfusion with potential use

  7. Automatic assessment of cardiac perfusion MRI

    DEFF Research Database (Denmark)

    Ólafsdóttir, Hildur; Stegmann, Mikkel Bille; Larsson, Henrik B.W.

    2004-01-01

    In this paper, a method based on Active Appearance Models (AAM) is applied for automatic registration of myocardial perfusion MRI. A semi-quantitative perfusion assessment of the registered image sequences is presented. This includes the formation of perfusion maps for three parameters; maximum up...

  8. Evaluation of MR perfusion abnormalities in organophosphorus poisoning and its correlation with SPECT

    Directory of Open Access Journals (Sweden)

    K Uday Bhanu

    2017-01-01

    Full Text Available Aim: Acute organophosphate (OP pesticide poisoning causes substantial morbidity and mortality worldwide. Many imaging modalities, such as computerized tomography (CT, magnetic resonance imaging (MRI, and single photon emission computed tomography (SPECT of the brain, have been used for quantitative assessment of the acute brain insult caused by acute OP poisoning. Perfusion defects on SPECT in acutely poisoned patients with OPs have been described, however, MR perfusion abnormalities have not been described in the literature. MR perfusion Imaging has the advantage of having higher spatial resolution, no radiation, and better availability. Materials and Methods: In this prospective study, 20 patients who ingested OP compounds were included. All the patients underwent brain SPECT on a dual head SPECT gamma camera and MRI brain on a 1.5T MR system. Neurocognitive tests were performed for all patients. Results: SPECT showed perfusion defects in 7 patients and total number of perfusion defects were 29. On MR perfusion, based on the cut-off values of normalized cerebral blood volume (nCBV ratios and normalized cerebral blood flow (nCBF ratios, the total number of patients showing perfusion defects were 6 and 8; and the total number of perfusion defects were 29 and 45, respectively. There was significant difference of the nCBV ratios and nCBF ratios between the control group (n = 20 and positive patients group (n = 6 and n = 8, respectively (P > 0.05. All the defects seen on SPECT were well appreciated on nCBF maps (MRI perfusion suggestive of 100% correlation. Conclusion: MR perfusion imaging can be used as an effective modality for evaluation in acute OP poisoning.

  9. Evaluation of MR perfusion abnormalities in organophosphorus poisoning and its correlation with SPECT.

    Science.gov (United States)

    Bhanu, K Uday; Khandelwal, Niranjan; Vyas, Sameer; Singh, Paramjeet; Prabhakar, Anuj; Mittal, B R; Bhalla, Ashish

    2017-01-01

    Acute organophosphate (OP) pesticide poisoning causes substantial morbidity and mortality worldwide. Many imaging modalities, such as computerized tomography (CT), magnetic resonance imaging (MRI), and single photon emission computed tomography (SPECT) of the brain, have been used for quantitative assessment of the acute brain insult caused by acute OP poisoning. Perfusion defects on SPECT in acutely poisoned patients with OPs have been described, however, MR perfusion abnormalities have not been described in the literature. MR perfusion Imaging has the advantage of having higher spatial resolution, no radiation, and better availability. In this prospective study, 20 patients who ingested OP compounds were included. All the patients underwent brain SPECT on a dual head SPECT gamma camera and MRI brain on a 1.5T MR system. Neurocognitive tests were performed for all patients. SPECT showed perfusion defects in 7 patients and total number of perfusion defects were 29. On MR perfusion, based on the cut-off values of normalized cerebral blood volume (nCBV) ratios and normalized cerebral blood flow (nCBF) ratios, the total number of patients showing perfusion defects were 6 and 8; and the total number of perfusion defects were 29 and 45, respectively. There was significant difference of the nCBV ratios and nCBF ratios between the control group (n = 20) and positive patients group (n = 6 and n = 8, respectively) (P > 0.05). All the defects seen on SPECT were well appreciated on nCBF maps (MRI perfusion) suggestive of 100% correlation. MR perfusion imaging can be used as an effective modality for evaluation in acute OP poisoning.

  10. Dynamic CT head phantom for perfusion and angiography studies

    Science.gov (United States)

    Russell, K.; Blazeski, A.; Dannecker, K.; Lee, Q. Y.; Holscher, C.; Donahue, C.; van Kampen, W.

    2010-03-01

    Contrast imaging is a compelling enhancement for the portable, flat panel-based brain CT scanner currently under development at Xoran. Due to the relative low temporal resolution of flat panel detectors, enabling tomographic imaging on such platform requires optimizing the imaging and injection protocols. A dynamic CT head phantom was designed to facilitate this task. The Dynamic Perfusion and Angiography Model (PAM), mimics tissue attenuation in CT images, provides physiological timing for angiography and perfusion studies, and moves fluid with properties similar to those of blood. The design consists of an arterial system, which contains bifurcating vessels that feed into perfusion chambers, mimicking blood flow through capillaries and smaller vessels, and a venous system, which is symmetrical to the arterial side and drains the perfusion chambers. The variation of geometry and flow rate in the phantom provides the physiological total time that fluid spends in the head, and the difference in material densities correlates to CT numbers for biological tissues. This paper discusses the design of Dynamic PAM and shows experimental results demonstrating its ability to realistically simulate blood flow. Results of dynamic imaging studies of the phantom are also presented.

  11. Quantitative myocardial perfusion magnetic resonance imaging: the impact of pulsatile flow on contrast agent bolus dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Graafen, Dirk; Hamer, Julia; Weber, Stefan; Schreiber, Laura M, E-mail: graafen@uni-mainz.de [Section of Medical Physics, Department of Radiology, Johannes Gutenberg University Medical Center, Mainz (Germany)

    2011-08-21

    Myocardial blood flow (MBF) can be quantified using T{sub 1}-weighted first-pass magnetic resonance imaging (MRI) in combination with a tracer-kinetic model, like MMID4. This procedure requires the knowledge of an arterial input function which is usually estimated from the left ventricle (LV). Dispersion of the contrast agent bolus may occur between the LV and the tissue of interest. The aim of this study was to investigate the dispersion under conditions of physiological pulsatile blood flow, and to simulate its effect on MBF quantification. The dispersion was simulated in coronary arteries using a computational fluid dynamics (CFD) approach. Simulations were accomplished on straight vessels with stenosis of different degrees and shapes. The results show that dispersion is more pronounced under resting conditions than during hyperemia. Stenosis leads to a reduction of dispersion. In consequence, dispersion results in a systematic MBF underestimation between -0.4% and -9.3%. The relative MBF error depends not only on the dispersion but also on the actual MBF itself. Since MBF under rest is more underestimated than under stress, myocardial perfusion reserve is overestimated between 0.1% and 4.5%. Considering other sources of errors in myocardial perfusion MRI, systematic errors of MBF by bolus dispersion are relatively small.

  12. Does machine perfusion decrease ischemia reperfusion injury?

    Science.gov (United States)

    Bon, D; Delpech, P-O; Chatauret, N; Hauet, T; Badet, L; Barrou, B

    2014-06-01

    In 1990's, use of machine perfusion for organ preservation has been abandoned because of improvement of preservation solutions, efficient without perfusion, easy to use and cheaper. Since the last 15 years, a renewed interest for machine perfusion emerged based on studies performed on preclinical model and seems to make consensus in case of expanded criteria donors or deceased after cardiac death donations. We present relevant studies highlighted the efficiency of preservation with hypothermic machine perfusion compared to static cold storage. Machines for organ preservation being in constant evolution, we also summarized recent developments included direct oxygenation of the perfusat. Machine perfusion technology also enables organ reconditioning during the last hours of preservation through a short period of perfusion on hypothermia, subnormothermia or normothermia. We present significant or low advantages for machine perfusion against ischemia reperfusion injuries regarding at least one primary parameter: risk of DFG, organ function or graft survival. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  13. Myocardial perfusion modeling using MRI

    DEFF Research Database (Denmark)

    Larsson, H B; Fritz-Hansen, T; Rostrup, Egill

    1996-01-01

    In the present study, it is shown that it is possible to quantify myocardial perfusion using magnetic resonance imaging in combination with gadolinium diethylenetriaminopentaacetic acid (Gd-DTPA). Previously, a simple model and method for measuring myocardial perfusion using an inversion recovery...... turbo-FLASH (fast low-angle shot) sequence and Gd-DTPA has been presented. Here, an extension of the model is presented taking into account fast and slow water exchange between the compartments, enabling the calculation of the unidirectional influx constant (Ki) for Gd-DTPA, the distribution volume...... of Gd-DTPA (lambda), the vascular blood volume (Vb), and the time delay through the coronary arteries (delta T). The model was evaluated by computer simulation and used on experimental results from seven healthy subjects. The results in the healthy volunteers for a region of interest placed...

  14. Inverse correspondence between hippocampal perfusion and verbal memory performance in older adults.

    Science.gov (United States)

    Rane, Swati; Ally, Brandon A; Hussey, Erin; Wilson, Tracy; Thornton-Wells, Tricia; Gore, John C; Donahue, Manus J

    2013-03-01

    Understanding physiological changes that precede irreversible tissue damage in age-related pathology is central to optimizing treatments that may prevent, or delay, cognitive decline. Cerebral perfusion is a tightly regulated physiological property, coupled to tissue metabolism and function, and abnormal (both elevated and reduced) hippocampal perfusion has been reported in a range of cognitive disorders. However, the size and location of the hippocampus complicates perfusion quantification, as many perfusion techniques acquire data with spatial resolution on the order of or beyond the size of the hippocampus, and are thus suboptimal in this region (especially in the presence of hippocampal atrophy and reduced flow scenarios). Here, the relationship between hippocampal perfusion and atrophy as a function of memory performance was examined in cognitively normal healthy older adults (n = 20; age=67 ± 7 yr) with varying genetic risk for dementia using a custom arterial spin labeling acquisition and analysis procedure. When controlling for hippocampal volume, it was found that hippocampal perfusion correlated inversely (P = 0.04) with memory performance despite absent hippocampal tissue atrophy or white matter disease. The hippocampal flow asymmetry (left hippocampus perfusion-right hippocampus perfusion) was significantly (P = 0.04) increased in APOE-ϵ4 carriers relative to noncarriers. These findings demonstrate that perfusion correlates more strongly than tissue volume with memory performance in cognitively normal older adults, and furthermore that an inverse trend between these two parameters suggests that elevation of neuronal activity, possibly mediated by neuroinflammation and/or excitation/inhibition imbalance, may be closely associated with minor changes in memory performance. Copyright © 2012 Wiley Periodicals, Inc.

  15. Simulation-based validation and arrival-time correction for Patlak analyses of Perfusion-CT scans

    Science.gov (United States)

    Bredno, Jörg; Hom, Jason; Schneider, Thomas; Wintermark, Max

    2009-02-01

    Blood-brain-barrier (BBB) breakdown is a hypothesized mechanism for hemorrhagic transformation in acute stroke. The Patlak analysis of a Perfusion Computed Tomography (PCT) scan measures the BBB permeability, but the method yields higher estimates when applied to the first pass of the contrast bolus compared to a delayed phase. We present a numerical phantom that simulates vascular and parenchymal time-attenuation curves to determine the validity of permeability measurements obtained with different acquisition protocols. A network of tubes represents the major cerebral arteries ipsi- and contralateral to an ischemic event. These tubes branch off into smaller segments that represent capillary beds. Blood flow in the phantom is freely defined and simulated as non-Newtonian tubular flow. Diffusion of contrast in the vessels and permeation through vessel walls is part of the simulation. The phantom allows us to compare the results of a permeability measurement to the simulated vessel wall status. A Patlak analysis reliably detects areas with BBB breakdown for acquisitions of 240s duration, whereas results obtained from the first pass are biased in areas of reduced blood flow. Compensating for differences in contrast arrival times reduces this bias and gives good estimates of BBB permeability for PCT acquisitions of 90-150s duration.

  16. Dosimetry in myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Toledo, Janine M.; Trindade, Bruno; Ribeiro, Tarcisio P.C. [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte (Brazil). Dept. de Engenharia Nuclear. Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares

    2011-07-01

    This paper conducts a dosimetric investigation on the myocardial perfusion image protocol, together with a literature reviewing, motivated by the significant statistic increasing on mortality, morbidity and disability associated with cardiovascular disease, surpassing infectious diseases. Nuclear Cardiology plays a role n the diagnostic functional evaluation of the heart and in the prognostic of patients with suspected or known cardiac ischemia. In the context of unstable myocardial ischemic syndrome, myocardial perfusion scintigraphy is a non-invasive procedure performed by administering a radiopharmaceutical targeted to the heart. As tool for this study are that the images obtained by thoracic angiotomography and abdominal aorta as a anatomic and functional information for model reproduction in SISCODES - System of Codes for Absorbed Dose Calculations based on Stochastic Methods. Data were manipulated in order to create a voxel computational model of the heart to be running in MCNP - Monte Carlo Neutron Particle Code. . It was assumed a homogeneous distribution of Tl-201 in cardiac muscle. Simulations of the transport of particles through the voxel and the interaction with the heart tissue were performed. As a result, the isodose curves in the heart model are displayed as well as the dose versus volume histogram of the heart muscle. We conclude that the present computational tools can generate doses distributed in myocardial perfusion. (author)

  17. Intestinal perfusion monitoring using photoplethysmography

    Science.gov (United States)

    Akl, Tony J.; Wilson, Mark A.; Ericson, M. Nance; Coté, Gerard L.

    2013-08-01

    In abdominal trauma patients, monitoring intestinal perfusion and oxygen consumption is essential during the resuscitation period. Photoplethysmography is an optical technique potentially capable of monitoring these changes in real time to provide the medical staff with a timely and quantitative measure of the adequacy of resuscitation. The challenges for using optical techniques in monitoring hemodynamics in intestinal tissue are discussed, and the solutions to these challenges are presented using a combination of Monte Carlo modeling and theoretical analysis of light propagation in tissue. In particular, it is shown that by using visible wavelengths (i.e., 470 and 525 nm), the perfusion signal is enhanced and the background contribution is decreased compared with using traditional near-infrared wavelengths leading to an order of magnitude enhancement in the signal-to-background ratio. It was further shown that, using the visible wavelengths, similar sensitivity to oxygenation changes could be obtained (over 50% compared with that of near-infrared wavelengths). This is mainly due to the increased contrast between tissue and blood in that spectral region and the confinement of the photons to the thickness of the small intestine. Moreover, the modeling results show that the source to detector separation should be limited to roughly 6 mm while using traditional near-infrared light, with a few centimeters source to detector separation leads to poor signal-to-background ratio. Finally, a visible wavelength system is tested in an in vivo porcine study, and the possibility of monitoring intestinal perfusion changes is showed.

  18. Ex-vivo lung perfusion.

    Science.gov (United States)

    Sanchez, Pablo G; D'Ovidio, Frank

    2012-10-01

    Lung transplant continues to be hampered by the number of available donors. Ex-vivo lung perfusion (EVLP) has emerged as an essential tool for the reassessment, under a controlled scenario, of lungs that initially did not meet transplantation criteria. The purpose of the current study is to review the most recent clinical and research reports and summarize their findings. Several centers have presented positive data when using ex-vivo perfusion to identify better grafts from the higher risk donor pool. The posttransplant results, when using these organs, are not significantly different from those obtained when using standard criteria donors. In addition, a great amount of research reports have emphasized the potential of ex-vivo perfusion as a platform in reducing the injurious effects of ischemia-reperfusion. EVLP has already proved its value as a tool to identify 'good' lungs from the previously rejected pool. But as new therapeutics arise , EVLP will also prove its value as a reproducible platform for their evaluation.

  19. Quantification of perfusion and risk stratification by myocardial perfusion SPECT; Quantifizierung der Perfusion und Risikostratifizierung durch die Myokardperfusions-SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Bernd [Ueberoertliche Gemeinschaft (GbR) fuer diagnostische und interventionelle Radiologie und Nuklearmedizin (DIRANUK), Bielefeld (Germany); Klinikum Bielefeld-Mitte (Germany). Klinik fuer Nuklearmedizin; Schaefer, W.M. [Kliniken Maria Hilf GmbH, Krankenhaus St. Franziskus, Moenchengladbach (Germany). Klinik fuer Nuklearmedizin

    2010-06-15

    Myocardial perfusion SPECT detects flow-limiting coronary artery disease with high sensitivity and specificity, enables semiquantification of severity and extensiveness of myocardial ischemia, and furthermore enables reliable assessment of future cardiac events independently of other clinical and diagnostic parameters. A normal myocardial perfusion SPECT is associated with a favorable prognosis and warrants restrictive patient management. Cardiac risk increases in relation to the severity of perfusion abnormalities. Differentiated analysis of quantitative parameters derived from myocardial perfusion SPECT provides effective risk stratification of patients with a large variety of risk factors. (orig.)

  20. Dynamic contrast enhanced MRI for perfusion quantification

    DEFF Research Database (Denmark)

    Andersen, Irene Klærke

    2002-01-01

    to be more robust. Successful brain perfusion quantication based on R1 weighted signals has not previously been reported, due to the poor signal to noise ratio of the images. Initial experiments reported in this thesis show that improved sequence may provide more accurate perfusion estimates in the brain...... with the tissue IRF. To obtain the IRF, the tissue curves and the input curves are deconvolved and perfusion is related to the peak of IRF. In this thesis, a new method for deconvolution of perfusion data is introduced. It is the Gaussian process for deconvolution, GPD. The method is compared to singular value......Magnetic resonance imaging, during bolus passage of a paramagnetic contrast agent, is used world-wide to obtain parameters that reflect the pathological state of tissue. Abnormal perfusion occurs in diseases such as stoke and tumour. Consequently, perfusion quantication could have signi cant...

  1. Ultrasound perfusion signal processing for tumor detection

    Science.gov (United States)

    Kim, MinWoo; Abbey, Craig K.; Insana, Michael F.

    2016-04-01

    Enhanced blood perfusion in a tissue mass is an indication of neo-vascularity and a sign of a potential malignancy. Ultrasonic pulsed-Doppler imaging is a preferred modality for noninvasive monitoring of blood flow. However, the weak blood echoes and disorganized slow flow make it difficult to detect perfusion using standard methods without the expense and risk of contrast enhancement. Our research measures the efficiency of conventional power-Doppler (PD) methods at discriminating flow states by comparing measurement performance to that of an ideal discriminator. ROC analysis applied to the experimental results shows that power Doppler methods are just 30-50 % efficient at perfusion flows less than 1ml/min, suggesting an opportunity to improve perfusion assessment through signal processing. A new perfusion estimator is proposed by extending the statistical discriminator approach. We show that 2-D perfusion color imaging may be enhanced using this approach.

  2. Quality assessment of a placental perfusion protocol

    DEFF Research Database (Denmark)

    Mathiesen, Line; Mose, Tina; Mørck, Thit Juul;

    2010-01-01

    the placental perfusion model in Copenhagen including control substances. The positive control substance antipyrine shows no difference in transport regardless of perfusion media used or of terms of delivery (n=59, pmarked dextran correspond with leakage criteria (...mlh(-1) from the fetal reservoir) when adding 2 (n=7) and 20mg (n=9) FITC-dextran/100ml fetal perfusion media. Success rate of the Copenhagen placental perfusions is provided in this study, including considerations and quality control parameters. Three checkpoints suggested to determine success rate...

  3. Myocardial perfusion reserve compared with peripheral perfusion reserve : A [13N]ammonia PET study

    NARCIS (Netherlands)

    Scholtens, A. M.; Tio, R. A.; Willemsen, A.; Dierckx, R. A. J. O.; Boersma, Hendrikus; Zeebregts, C. J.; Glaudemans, A. W. J. M.; Slart, R. H. J. A.

    2011-01-01

    INTRODUCTION: [13N]ammonia PET allows quantification of myocardial perfusion. The similarity between peripheral flow and myocardial perfusion is unclear. We compared perfusion flow in the myocardium with the upper limb during rest and adenosine stress [13N]ammonia PET to establish whether peripheral

  4. Perfusion Angiography in Acute Ischemic Stroke

    Directory of Open Access Journals (Sweden)

    Fabien Scalzo

    2016-01-01

    Full Text Available Visualization and quantification of blood flow are essential for the diagnosis and treatment evaluation of cerebrovascular diseases. For rapid imaging of the cerebrovasculature, digital subtraction angiography (DSA remains the gold standard as it offers high spatial resolution. This paper lays out a methodological framework, named perfusion angiography, for the quantitative analysis and visualization of blood flow parameters from DSA images. The parameters, including cerebral blood flow (CBF and cerebral blood volume (CBV, mean transit time (MTT, time-to-peak (TTP, and Tmax, are computed using a bolus tracking method based on the deconvolution of the time-density curve on a pixel-by-pixel basis. The method is tested on 66 acute ischemic stroke patients treated with thrombectomy and/or tissue plasminogen activator (tPA and also evaluated on an estimation task with known ground truth. This novel imaging tool provides unique insights into flow mechanisms that cannot be observed directly in DSA sequences and might be used to evaluate the impact of endovascular interventions more precisely.

  5. Local cortical hypoperfusion imaged with CT perfusion during postictal Todd's paresis

    Energy Technology Data Exchange (ETDEWEB)

    Mathews, Marlon S.; Binder, Devin K. [University of California, Department of Neurological Surgery, Irvine, CA (United States); Smith, Wade S. [University of California, Department of Neurology, San Francisco, CA (United States); Wintermark, Max; Dillon, William P. [University of California, Department of Radiology, San Francisco, CA (United States)

    2008-05-15

    Postictal ('Todd's') paralysis, or 'epileptic hemiplegia,' is a well-known complication of focal or generalized epileptic seizures. However, it is unclear whether the pathophysiology of Todd's paralysis is related to alterations in cerebral perfusion. We report CT perfusion findings in a patient presenting with postictal aphasia and right hemiparesis. A 62-year-old woman with a history of alcohol abuse, closed head injury and posttraumatic epilepsy, presented with acute onset aphasia and right hemiparesis. A non-contrast head CT scan demonstrated no acute hemorrhage. Left hemispheric ischemia was suspected, and the patient was considered for acute thrombolytic therapy. MRI revealed a subtle increase in signal intensity involving the left medial temporal, hippocampal and parahippocampal regions on both T2-weighted FLAIR and diffusion-weighted sequences. CT angiography and CT perfusion study were performed. The CT perfusion study and CT angiography demonstrated a dramatic reduction in cerebral blood flow and blood volume involving the entire left hemisphere, but with relative symmetry of mean transit time, ruling out a large vessel occlusion. Clinical resolution of the aphasia and hemiparesis occurred within a few hours, and correlated with normalization of perfusion to the left hemisphere (detected by MR perfusion). This unique case is the first in which clinical evidence of Todd's paralysis has been correlated with reversible postictal hemispheric changes on CT and MR perfusion studies. This is important because CT perfusion study is being used more and more in the diagnosis of acute stroke, and one needs to be careful to not misinterpret the data. (orig.)

  6. Transport of benzo[alpha]pyrene in the dually perfused human placenta perfusion model: effect of albumin in the perfusion medium

    DEFF Research Database (Denmark)

    Mathiesen, Line; Rytting, Erik; Mose, Tina

    2009-01-01

    P is lipophilic and studies using cell culture medium in 6-hr placenta perfusions showed minimal transport through the placenta. To increase the solubility of BaP in perfusion medium and to increase physiological relevance, perfusions were also performed with albumin added to the perfusion medium [2 and 30 mg...

  7. Long term perfusion system supporting adipogenesis.

    Science.gov (United States)

    Abbott, Rosalyn D; Raja, Waseem K; Wang, Rebecca Y; Stinson, Jordan A; Glettig, Dean L; Burke, Kelly A; Kaplan, David L

    2015-08-01

    Adipose tissue engineered models are needed to enhance our understanding of disease mechanisms and for soft tissue regenerative strategies. Perfusion systems generate more physiologically relevant and sustainable adipose tissue models, however adipocytes have unique properties that make culturing them in a perfusion environment challenging. In this paper we describe the methods involved in the development of two perfusion culture systems (2D and 3D) to test their applicability for long term in vitro adipogenic cultures. It was hypothesized that a silk protein biomaterial scaffold would provide a 3D framework, in combination with perfusion flow, to generate a more physiologically relevant sustainable adipose tissue engineered model than 2D cell culture. Consistent with other studies evaluating 2D and 3D culture systems for adipogenesis we found that both systems successfully model adipogenesis, however 3D culture systems were more robust, providing the mechanical structure required to contain the large, fragile adipocytes that were lost in 2D perfused culture systems. 3D perfusion also stimulated greater lipogenesis and lipolysis and resulted in decreased secretion of LDH compared to 2D perfusion. Regardless of culture configuration (2D or 3D) greater glycerol was secreted with the increased nutritional supply provided by perfusion of fresh media. These results are promising for adipose tissue engineering applications including long term cultures for studying disease mechanisms and regenerative approaches, where both acute (days to weeks) and chronic (weeks to months) cultivation are critical for useful insight.

  8. Personality factors correlate with regional cerebral perfusion.

    Science.gov (United States)

    O'Gorman, R L; Kumari, V; Williams, S C R; Zelaya, F O; Connor, S E J; Alsop, D C; Gray, J A

    2006-06-01

    There is an increasing body of evidence pointing to a neurobiological basis of personality. The purpose of this study was to investigate the biological bases of the major dimensions of Eysenck's and Cloninger's models of personality using a noninvasive magnetic resonance perfusion imaging technique in 30 young, healthy subjects. An unbiased voxel-based analysis was used to identify regions where the regional perfusion demonstrated significant correlation with any of the personality dimensions. Highly significant positive correlations emerged between extraversion and perfusion in the basal ganglia, thalamus, inferior frontal gyrus and cerebellum and between novelty seeking and perfusion in the cerebellum, cuneus and thalamus. Strong negative correlations emerged between psychoticism and perfusion in the basal ganglia and thalamus and between harm avoidance and perfusion in the cerebellar vermis, cuneus and inferior frontal gyrus. These observations suggest that personality traits are strongly associated with resting cerebral perfusion in a variety of cortical and subcortical regions and provide further evidence for the hypothesized neurobiological basis of personality. These results may also have important implications for functional neuroimaging studies, which typically rely on the modulation of cerebral hemodynamics for detection of task-induced activation since personality effects may influence the intersubject variability for both task-related activity and resting cerebral perfusion. This technique also offers a novel approach for the exploration of the neurobiological correlates of human personality.

  9. Sumatriptan and cerebral perfusion in healthy volunteers.

    Science.gov (United States)

    Scott, A K; Grimes, S; Ng, K; Critchley, M; Breckenridge, A M; Thomson, C; Pilgrim, A J

    1992-04-01

    1. The effect of sumatriptan on regional cerebral perfusion was studied in healthy volunteers. 2. Intravenous sumatriptan (2 mg) had no detectable effect on regional cerebral perfusion as measured using a SPECT system with 99technetiumm labelled hexemethylpropyleneamineoxime. 3. Sumatriptan had no effect on pulse, blood pressure or ECG indices. 4. All six volunteers experienced minor adverse effects during the intravenous infusion.

  10. Regional Cerebral Perfusion in Progressive Supranuclear Palsy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Yong; Lee, Ki Hyeong; Yoon, Byung Woo; Lee, Sang Bok; Jeon, Beom S. [Samsung Medical Center, Seoul (Korea, Republic of); Lee, Kyung Han; Lee, Myung Chul [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1996-03-15

    Progressive supranuclear palsy (PSP) is a Parkinson-plus syndrome characterized clinically by supranuclear ophthalmoplegia, pseudobulbar palsy, axial rigidity, bradykinesia, postural instability and dementia. Presence of dementia and lack of cortical histopathology suggest the derangement of cortical function by pathological changes in subcortical structures in PSP, which is supported by the pattern of behavioral changes and measurement of brain metabolism using positron emission tomography. This study was done to examine whether there are specific changes of regional cerebral perfusion in PSP and whether there is a correlation between severity of motor abnormaility and degree of changes in cerebral perfusion. We measured regional cerebral perfusion indices in 5 cortical and 2 subcortical areas in 6 patients with a clinical diagnosis of PSP and 6 healthy age and sex matched controls using Tc-99m-HMPAO SPECT. Compared with age and sex matched controls, only superior frontal regional perfusion index was significantly decreased in PSP (p<0.05). There was no correlation between the severity of the motor abnormality and any of the regional cerebral perfusion indices (p>0.05). We affirm the previous reports that perfusion in superior frontal cortex is decreased in PSP. Based on our results that there was no correlation between severity of motor abnormality and cerebral perfusion in the superior frontal cortex, nonmotoric symptoms including dementia needs to be looked at whether there is a correlation with the perfusion abnormality in superior frontal cortex

  11. Methodology for ventilation/perfusion SPECT

    DEFF Research Database (Denmark)

    Bajc, Marika; Neilly, Brian; Miniati, Massimo;

    2010-01-01

    radiolabeled liquid aerosols are not restricted to the presence of obstructive lung disease. Radiolabeled macroaggregated human albumin is the imaging agent of choice for perfusion scintigraphy. An optimal combination of nuclide activities and acquisition times for ventilation and perfusion, collimators......Ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) is the scintigraphic technique of choice for the diagnosis of pulmonary embolism and many other disorders that affect lung function. Data from recent ventilation studies show that the theoretic advantages of Technegas over......, and imaging matrix yields an adequate V/Q SPECT study in approximately 20 minutes of imaging time. The recommended protocol based on the patient remaining in an unchanged position during the initial ventilation study and the perfusion study allows presentation of matching ventilation and perfusion slices...

  12. Quantitative Tc-99m myocardial perfusion SPECT with 180[degree] acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Ye, J.

    1992-01-01

    Myocardial perfusion single photon emission computed tomography (SPECT) images using 180[degrees] acquisition are degraded by the effects of scatter, nonuniform attenuation and system geometric resolution variation with source depth. Using a 180[degrees] scan orbit which is closer to the heart may provide higher image resolution, signal-to-noise ratio and defect-to-normal contrast than using a 360[degrees] orbit, however, significant object shape distortion has been observed in the 180[degrees] reconstructed images. A method has been developed that combines filtered back-projection (FBP) with iterative attenuation and three-dimensional (3-D) resolution compensation for Tc-99m myocardial perfusion imaging, data. The non-uniform attenuation coefficient distribution is obtained by a quick transmission scan using a flood source and segmentation of the reconstructed transmission image to define areas of significantly different attenuation. A priori attenuation coefficients are assigned to the areas to form the attenuation distribution map. The 3-D correction is accomplished by including both the non-uniform attenuation and depth-dependent resolution variation in the reprojection procedure of an iterative correction algorithm. The method was evaluated with both simulated and experimental data using clinical protocols with a cardiac phantom. A significant improvement in image resolution was observed with line source images was reduced from approximately 10 mm to 7.l5 mm after 7 iterations of the 3-D correction. The contrast of two perfusion defects to the surrounding normally perfused regions was significantly improved with the correction. Significant improvement in uniformity at different positions in the 100% perfused areas in the myocardium was also observed. The normalized root squared error (NRSE) of one transaxial image from the original source distribution in the simulation study was reduced from 0.8 to 0.2 after 5 iterations of the 3-D correction.

  13. Cerebral perfusion SPECT in transient ischemic attack

    Energy Technology Data Exchange (ETDEWEB)

    You, D.-L. E-mail: dlyou@mail.kfcc.org.tw; Shieh, F.-Y.; Tzen, K.-Y.; Tsai, M.-F.; Kao, P.-F

    2000-04-01

    Purpose: The purpose of our study is to evaluate the efficacy of cerebral perfusion single photon emission computerized tomography (SPECT) in patients with transient ischemic attack (TIA). Methods: Thirty-seven patients with TIA were collected for study. All patients had transient focal neurological symptoms or signs with complete recovery within 24 h after onset. The patients underwent cerebral perfusion SPECT between 6 h and 11 days after onset, with 10 cases performed within 24 h (group A), nine cases performed between 1 and 3 days (group B), 11 cases performed between 3 and 5 days (group C), and seven cases performed after more than 5 days (group D). A semi-quantitative method was used for analyzing the SPECT data, and the difference ratios between lesion side and contralateral normal side were calculated on each pair of regions of interest. Results: In total, 78.4% (29/37) of patients had reduced perfusion in the cerebral cortical regions or deep nuclei, and the regions with reduced perfusion corresponded with clinical presentations of the patients. The abnormal rate with reduced perfusion was 90.0% in group A, 77.8% in group B, 72.7% in group C and 71.4% in group D. Cross cerebellar diaschisis (CCD) was present in seven patients, and all of the primary cerebral perfusion defects of these patients were located at the territory of left or right middle cerebral artery. Conclusion: Cerebral perfusion SPECT is a potential tool to detect cerebral perfusion defects and CCD in patients with TIA. Although the perfusion defect may persist more than 5 days after onset, we suggest cerebral perfusion SPECT should be performed as soon as possible.

  14. Brain perfusion imaging using a Reconstruction-of-Difference (RoD) approach for cone-beam computed tomography

    Science.gov (United States)

    Mow, M.; Zbijewski, W.; Sisniega, A.; Xu, J.; Dang, H.; Stayman, J. W.; Wang, X.; Foos, D. H.; Koliatsos, V.; Aygun, N.; Siewerdsen, J. H.

    2017-03-01

    Purpose: To improve the timely detection and treatment of intracranial hemorrhage or ischemic stroke, recent efforts include the development of cone-beam CT (CBCT) systems for perfusion imaging and new approaches to estimate perfusion parameters despite slow rotation speeds compared to multi-detector CT (MDCT) systems. This work describes development of a brain perfusion CBCT method using a reconstruction of difference (RoD) approach to enable perfusion imaging on a newly developed CBCT head scanner prototype. Methods: A new reconstruction approach using RoD with a penalized-likelihood framework was developed to image the temporal dynamics of vascular enhancement. A digital perfusion simulation was developed to give a realistic representation of brain anatomy, artifacts, noise, scanner characteristics, and hemo-dynamic properties. This simulation includes a digital brain phantom, time-attenuation curves and noise parameters, a novel forward projection method for improved computational efficiency, and perfusion parameter calculation. Results: Our results show the feasibility of estimating perfusion parameters from a set of images reconstructed from slow scans, sparse data sets, and arc length scans as short as 60 degrees. The RoD framework significantly reduces noise and time-varying artifacts from inconsistent projections. Proper regularization and the use of overlapping reconstructed arcs can potentially further decrease bias and increase temporal resolution, respectively. Conclusions: A digital brain perfusion simulation with RoD imaging approach has been developed and supports the feasibility of using a CBCT head scanner for perfusion imaging. Future work will include testing with data acquired using a 3D-printed perfusion phantom currently and translation to preclinical and clinical studies.

  15. Abolished ventilation and perfusion of lung caused by blood clot in the left main bronchus

    DEFF Research Database (Denmark)

    Afzelius, P; Bergmann, A; Henriksen, J H

    2015-01-01

    /Q) scintigraphy with single-photon emission CT (SPECT)/CT. V/Q SPECT/CT demonstrated abolished ventilation due to obstruction of the left main bronchus and markedly reduced perfusion of the entire left lung, a condition that was completely reversed after removal of a blood clot. We present the first pictorially......It is generally assumed that the lungs possess arterial autoregulation associated with bronchial obstruction. A patient with pneumonia and congestive heart failure unexpectedly developed frequent haemoptysis. High-resolution CT and diagnostic CT were performed as well as ventilation/perfusion (V...

  16. Stability of radiomic features in CT perfusion maps

    Science.gov (United States)

    Bogowicz, M.; Riesterer, O.; Bundschuh, R. A.; Veit-Haibach, P.; Hüllner, M.; Studer, G.; Stieb, S.; Glatz, S.; Pruschy, M.; Guckenberger, M.; Tanadini-Lang, S.

    2016-12-01

    This study aimed to identify a set of stable radiomic parameters in CT perfusion (CTP) maps with respect to CTP calculation factors and image discretization, as an input for future prognostic models for local tumor response to chemo-radiotherapy. Pre-treatment CTP images of eleven patients with oropharyngeal carcinoma and eleven patients with non-small cell lung cancer (NSCLC) were analyzed. 315 radiomic parameters were studied per perfusion map (blood volume, blood flow and mean transit time). Radiomics robustness was investigated regarding the potentially standardizable (image discretization method, Hounsfield unit (HU) threshold, voxel size and temporal resolution) and non-standardizable (artery contouring and noise threshold) perfusion calculation factors using the intraclass correlation (ICC). To gain added value for our model radiomic parameters correlated with tumor volume, a well-known predictive factor for local tumor response to chemo-radiotherapy, were excluded from the analysis. The remaining stable radiomic parameters were grouped according to inter-parameter Spearman correlations and for each group the parameter with the highest ICC was included in the final set. The acceptance level was 0.9 and 0.7 for the ICC and correlation, respectively. The image discretization method using fixed number of bins or fixed intervals gave a similar number of stable radiomic parameters (around 40%). The potentially standardizable factors introduced more variability into radiomic parameters than the non-standardizable ones with 56-98% and 43-58% instability rates, respectively. The highest variability was observed for voxel size (instability rate  >97% for both patient cohorts). Without standardization of CTP calculation factors none of the studied radiomic parameters were stable. After standardization with respect to non-standardizable factors ten radiomic parameters were stable for both patient cohorts after correction for inter-parameter correlations. Voxel size

  17. First-pass studies of acute lung injury.

    Science.gov (United States)

    Chu, R Y; Sidhu, N; Basmadjian, G; Burow, R; Allen, E W

    1993-10-01

    Mild hydrochloric acid was introduced to a caudal lung section in each of eight dogs to induce injury. Transits of 99mTc-labeled red blood cells (RBC) and [123I]iodoantipyrine (IAP) injected intravenously were recorded by a scintillation camera. Lungs and blood samples were analyzed post-mortem. Peak-to-equilibrium ratios (P/E) of RBC time-activity curves were computed to be 3.83 +/- 0.54 for the control lung, 2.58 +/- 0.55 for the injured lung and 2.23 +/- 0.58 for the injured caudal section. For IAP, the respective results were 3.78 +/- 0.29, 2.02 +/- 0.18 and 1.77 +/- 0.17. The decrease of P/E in injured areas was attributed to reduced blood flow. Using mean transit times of the tracers, we computed extravascular lung water per unit blood volume to be 0.35 +/- 0.18 for the control lungs and an increased value of 0.68 +/- 0.24 for the injured lungs. These results displayed sensitivity to injury, but were gross underestimates relative to the corresponding values of 2.04 +/- 0.54 and 4.56 +/- 1.85 in post-mortem analyses.

  18. First-pass studies of acute lung injury

    Energy Technology Data Exchange (ETDEWEB)

    Chu, R.Y.L.; Sidhu, N.; Basmadjian, G.; Burow, R.; Allen, E.W. (Oklahoma Univ. and Dept. of Veterans Affairs Medical Centre, Oklahoma City, OK (United States))

    1993-10-01

    Mild hydrochloric acid was introduced to a caudal lung section in each of eight dogs to induce injury. Transits of [sup 99m]Tc-labeled red blood cells (RBC) and [[sup 123]I]iodoantipyrine (IAP) injected intravenously were recorded by a scintillation camera. Lungs and blood samples were analyzed post-mortem. Peak-to-equilibrium ratios (P/E) of RBC time-activity curves were computed to be 3.83 [+-] 0.54 for the control lung, 2.58 [+-] 0.55 for the injured lung and 2.23 [+-] 0.58 for the injured caudal section. For IAP, the respective results were 3.78 [+-] 0.29, 2.02 [+-] 0.18 and 1.77 [+-] 0.17. The decrease of P/E in injured areas was attributed to reduced blood flow. Using mean transit times of the tracers, we computed extravascular lung water per unit blood volume to be 0.35 [+-] 0.18 for the control lungs and an increased value of 0.68 [+-] 0.24 for the injured lungs. These results displayed sensitivity to injury, but were gross underestimates relative to the corresponding values of 2.04 [+-] 0.54 and 4.56 [+-] 1.85 in post-mortem analyses. (Author).

  19. Development of a theory for generating regional cardiac perfusion images during coronary angiography in the coronary angiography lab.

    Science.gov (United States)

    Sakaguchi, Takuya; Ichihara, Takashi; Trost, Jeffrey C; Yousuf, Omair; Lima, Joao A C; Yao, Jingwu; George, Richard T

    2014-01-01

    The purpose of this study was to develop a novel theory and method for generating regional myocardial perfusion images using fluoroscopy in the coronary angiography lab. We modified the Kety model to introduce the Patlak plot method for two-dimensional fluoroperfusion (FP) imaging. For evaluation, seven porcine models of myocardial ischemia with stenosis in the left coronary artery were prepared. Rest and stress FP imaging were performed using cardiovascular X-ray imaging equipment during the injection of iopamidol via the left main coronary artery. Images were acquired and retrospectively ECG gated at 80 % of the R-R interval. FP myocardial blood flow (MBF) was obtained using the Patlak plot method applied to time-intensity curve data of the proximal artery and myocardium. The results were compared to microsphere MBF measurements. Time-intensity curves were also used to generate color-coded FP maps. There was a moderate linear correlation between the calculated FP MBF and the microsphere MBF (y = 0.9758x + 0.5368, R² = 0.61). The color-coded FP maps were moderately correlated with the regional distribution of flow. This novel method of first-pass contrast-enhanced two-dimensional fluoroscopic imaging can quantify MBF and provide color coded FP maps representing regional myocardial perfusion.

  20. Cochlear perfusion with a viscous fluid.

    Science.gov (United States)

    Wang, Yi; Olson, Elizabeth S

    2016-07-01

    The flow of viscous fluid in the cochlea induces shear forces, which could provide benefit in clinical practice, for example to guide cochlear implant insertion or produce static pressure to the cochlear partition or wall. From a research standpoint, studying the effects of a viscous fluid in the cochlea provides data for better understanding cochlear fluid mechanics. However, cochlear perfusion with a viscous fluid may damage the cochlea. In this work we studied the physiological and anatomical effects of perfusing the cochlea with a viscous fluid. Gerbil cochleae were perfused at a rate of 2.4 μL/min with artificial perilymph (AP) and sodium hyaluronate (Healon, HA) in four different concentrations (0.0625%, 0.125%, 0.25%, 0.5%). The different HA concentrations were applied either sequentially in the same cochlea or individually in different cochleae. The perfusion fluid entered from the round window and was withdrawn from basal scala vestibuli, in order to perfuse the entire perilymphatic space. Compound action potentials (CAP) were measured after each perfusion. After perfusion with increasing concentrations of HA in the order of increasing viscosity, the CAP thresholds generally increased. The threshold elevation after AP and 0.0625% HA perfusion was small or almost zero, and the 0.125% HA was a borderline case, while the higher concentrations significantly elevated CAP thresholds. Histology of the cochleae perfused with the 0.0625% HA showed an intact Reissner's membrane (RM), while in cochleae perfused with 0.125% and 0.25% HA RM was torn. Thus, the CAP threshold elevation was likely due to the broken RM, likely caused by the shear stress produced by the flow of the viscous fluid. Our results and analysis indicate that the cochlea can sustain, without a significant CAP threshold shift, up to a 1.5 Pa shear stress. Beside these finding, in the 0.125% and 0.25% HA perfusion cases, a temporary CAP threshold shift was observed, perhaps due to the presence and

  1. Cochlear perfusion with a viscous fluid

    Science.gov (United States)

    Wang, Yi; Olson, Elizabeth S.

    2016-01-01

    The flow of viscous fluid in the cochlea induces shear forces, which could provide benefit in clinical practice, for example to guide cochlear implant insertion or produce static pressure to the cochlear partition or wall. From a research standpoint, studying the effects of a viscous fluid in the cochlea provides data for better understanding cochlear fluid mechanics. However, cochlear perfusion with a viscous fluid may damage the cochlea. In this work we studied the physiological and anatomical effects of perfusing the cochlea with a viscous fluid. Gerbil cochleae were perfused at a rate of 2.4 μL/min with artificial perilymph (AP) and sodium hyaluronate (Healon, HA) in four different concentrations (0.0625%, 0.125%, 0.25%, 0.5%). The different HA concentrations were applied either sequentially in the same cochlea or individually in different cochleae. The perfusion fluid entered from the round window and was withdrawnfrom basal scala vestibuli, in order to perfuse the entire perilymphatic space. Compound action potentials (CAP) were measured after each perfusion. After perfusion with increasing concentrations of HA in the order of increasing viscosity, the CAP thresholds generally increased. The threshold elevation after AP and 0.0625% HA perfusion was small or almost zero, and the 0.125% HA was a borderline case, while the higher concentrations significantly elevated CAP thresholds. Histology of the cochleae perfused with the 0.0625% HA showed an intact Reissner’s membrane, while in cochleae perfused with 0.125% and 0.25% HA Reissner’s membrane (RM) was torn. Thus, the CAP threshold elevation was likely due to the broken of RM, which likely caused by the shear stress produced by the flow of the viscous fluid. Our results and analysis indicate that the cochlea can sustain, without a significant CAP threshold shift, up to a 1.5 Pa shear stress. Beside these finding, in the 0.125% and 0.25% HA perfusion cases, a temporary CAP threshold shift was observed

  2. Computed Tomography (CT) Perfusion in Abdominal Cancer

    DEFF Research Database (Denmark)

    Hansen, Martin Lundsgaard; Norling, Rikke; Lauridsen, Carsten

    2013-01-01

    Computed Tomography (CT) Perfusion is an evolving method to visualize perfusion in organs and tissue. With the introduction of multidetector CT scanners, it is now possible to cover up to 16 cm in one rotation, and thereby making it possible to scan entire organs such as the liver with a fixed...... table position. Advances in reconstruction algorithms make it possible to reduce the radiation dose for each examination to acceptable levels. Regarding abdominal imaging, CT perfusion is still considered a research tool, but several studies have proven it as a reliable non-invasive technique...... for assessment of vascularity. CT perfusion has also been used for tumor characterization, staging of disease, response evaluation of newer drugs targeted towards angiogenesis and as a method for early detection of recurrence after radiation and embolization. There are several software solutions available...

  3. Dynamic contrast enhanced MRI for perfusion quantification

    DEFF Research Database (Denmark)

    Andersen, Irene Klærke

    2002-01-01

    to be more robust. Successful brain perfusion quantication based on R1 weighted signals has not previously been reported, due to the poor signal to noise ratio of the images. Initial experiments reported in this thesis show that improved sequence may provide more accurate perfusion estimates in the brain....... Images obtained during bolus passage are noisy, and the bolus is not an ideal impulse as it reaches the brain. The brain response to an ideal impulse is called the residual impulse response function, IRF. Thus, the measured tissue curves are expressed as the convolution of the input function...... with the tissue IRF. To obtain the IRF, the tissue curves and the input curves are deconvolved and perfusion is related to the peak of IRF. In this thesis, a new method for deconvolution of perfusion data is introduced. It is the Gaussian process for deconvolution, GPD. The method is compared to singular value...

  4. Vicarious Audiovisual Learning in Perfusion Education

    Science.gov (United States)

    Rath, Thomas E.; Holt, David W.

    2010-01-01

    Abstract: Perfusion technology is a mechanical and visual science traditionally taught with didactic instruction combined with clinical experience. It is difficult to provide perfusion students the opportunity to experience difficult clinical situations, set up complex perfusion equipment, or observe corrective measures taken during catastrophic events because of patient safety concerns. Although high fidelity simulators offer exciting opportunities for future perfusion training, we explore the use of a less costly low fidelity form of simulation instruction, vicarious audiovisual learning. Two low fidelity modes of instruction; description with text and a vicarious, first person audiovisual production depicting the same content were compared. Students (n = 37) sampled from five North American perfusion schools were prospectively randomized to one of two online learning modules, text or video. These modules described the setup and operation of the MAQUET ROTAFLOW standalone centrifugal console and pump. Using a 10 question multiple-choice test, students were assessed immediately after viewing the module (test #1) and then again 2 weeks later (test #2) to determine cognition and recall of the module content. In addition, students completed a questionnaire assessing the learning preferences of today’s perfusion student. Mean test scores from test #1 for video learners (n = 18) were significantly higher (88.89%) than for text learners (n = 19) (74.74%), (p perfusion training on subjects such as equipment setup and operation. Video learning appears to improve cognition and retention of learned content and may play an important role in how we teach perfusion in the future, as simulation technology becomes more prevalent. PMID:21313929

  5. Perfusion magnetic resonance imaging of the liver

    Institute of Scientific and Technical Information of China (English)

    Choon; Hua; Thng; Tong; San; Koh; David; J; Collins; Dow; Mu; Koh

    2010-01-01

    Perfusion magnetic resonance imaging (MRI) studies quantify the microcirculatory status of liver parenchyma and liver lesions, and can be used for the detection of liver metastases, assessing the effectiveness of antiangiogenic therapy, evaluating tumor viability after anticancer therapy or ablation, and diagnosis of liver cirrhosis and its severity. In this review, we discuss the basic concepts of perfusion MRI using tracer kinetic modeling, the common kinetic models applied for analyses, the MR scanning t...

  6. Hydroxyethyl starch solution for extracorporeal tissue perfusion.

    Science.gov (United States)

    Taeger, Christian D; Friedrich, Oliver; Drechsler, Caroline; Weigand, Annika; Hobe, Frieder; Geppert, Carol I; Münch, Frank; Birkholz, Torsten; Buchholz, Rainer; Horch, Raymund E; Präbst, Konstantin

    2016-11-04

    In the field of free flap transfer in reconstructive surgery, the trans- or replanted tissue always undergoes cell damage during ischemia to a more or less strong extent. In previous studies we already showed that conserving muscle transplants by means of extracorporeal perfusion over a period of 6 hours by using a crystalloid solution for perfusion. However, we observed significant edema formation. In this study we aimed at reducing the edema formation by using an iso-oncotic colloid as perfusion solution. This way we wanted to evaluate a possible new application of hydroxyl-ethyl starch in an extracorporeal setup to exploit potential benefits of the colloid.Examined parameters include the muscles' functionality with external field stimulation, histological examination and edema formation. Perfused muscles showed a statistically significant higher ability to exert force compared to nonperfused ones. These findings can be confirmed using Annexin V as marker for cell damage, as perfusion of muscle tissue limits damage significantly compared to nonperfused tissue. Substituting the electrolyte perfusion solution with a colloidal one shows the tendency to reduce the edema formation however without statistical significance.

  7. Equilibrium-phase high spatial resolution contrast-enhanced MR angiography at 1.5T in preoperative imaging for perforator flap breast reconstruction.

    Directory of Open Access Journals (Sweden)

    Bas Versluis

    Full Text Available OBJECTIVES: The aim was (i to evaluate the accuracy of equilibrium-phase high spatial resolution (EP contrast-enhanced magnetic resonance angiography (CE-MRA at 1.5T using a blood pool contrast agent for the preoperative evaluation of deep inferior epigastric artery perforator branches (DIEP, and (ii to compare image quality with conventional first-pass CE-MRA. METHODS: Twenty-three consecutive patients were included. All patients underwent preoperative CE-MRA to determine quality and location of DIEP. First-pass imaging after a single bolus injection of 10 mL gadofosveset trisodium was followed by EP imaging. MRA data were compared to intra-operative findings, which served as the reference standard. RESULTS: There was 100% agreement between EP CE-MRA and surgical findings in identifying the single best perforator branch. All EP acquisitions were of diagnostic quality, whereas in 10 patients the quality of the first-pass acquisition was qualified as non-diagnostic. Both signal- and contrast-to-noise ratios were significantly higher for EP imaging in comparison with first-pass acquisitions (p<0.01. CONCLUSIONS: EP CE-MRA of DIEP in the preoperative evaluation of patients undergoing a breast reconstruction procedure is highly accurate in identifying the single best perforator branch at 1.5Tesla (T. Besides accuracy, image quality of EP imaging proved superior to conventional first-pass CE-MRA.

  8. Metabolic Characteristics of Human Hearts Preserved for 12 Hours by Static Storage, Antegrade Perfusion or Retrograde Coronary Sinus Perfusion

    Science.gov (United States)

    Cobert, Michael L.; Merritt, Matthew E.; West, LaShondra M.; Ayers, Colby; Jessen, Michael E.; Peltz, Matthias

    2014-01-01

    Objective(s) Machine perfusion of donor hearts is a promising strategy to increase the donor pool. Antegrade perfusion is effective but can lead to aortic valve incompetence and non-nutrient flow. Experience with retrograde coronary sinus perfusion of donor hearts has been limited. We tested the hypothesis that retrograde perfusion could support myocardial metabolism over an extended donor ischemic interval. Methods Human hearts from donors rejected or not offered for transplantation were preserved for 12 hours in University of Wisconsin Machine Perfusion Solution by: 1. Static hypothermic storage 2. Hypothermic antegrade machine perfusion or 3. Hypothermic retrograde machine perfusion. Myocardial oxygen consumption (MVO2), and lactate accumulation were measured. Ventricular tissue was collected for proton (1H) and phosphorus-31 (31P) magnetic resonance spectroscopy (MRS) to evaluate the metabolic state of the myocardium. Myocardial water content was determined at end-experiment. Results Stable perfusion parameters were maintained throughout the perfusion period with both perfusion techniques. Lactate/alanine ratios were lower in perfused hearts compared to static hearts (pperfused groups. High energy phosphates were better preserved in both perfused groups (pperfused (80.2±.8%) compared to both antegrade perfused (76.6±.8%, p=.02) and static storage hearts (76.7±1%, p=.02). Conclusions In conclusion, machine perfusion by either the antegrade or the retrograde technique can support myocardial metabolism over long intervals. Machine perfusion appears promising for long term preservation of human donor hearts. PMID:24642559

  9. Detection of extracardiac disease during Tl-201 myocardial perfusion study

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chan H.; Lee, Myoung Hoon; Yoon, Seok Nam; Hwang, Kyung Hoon [College of Medicine, Ajou Univ., Suwon (Korea, Republic of)

    2001-07-01

    It is important to observe extracardiac disease processes (ECD) during cardiac perfusion imaging for valuable information can be obtained at no extracost to patients. The aim of the study is to find out the frequency of ECD during Tl-201 stress myocardial perfusion imaging (TSMPI). Retrospective evaluation of 552 TSMPI was done. There were 229 males and 223 females reffered for evaluation of possible ischemic heart disease. Their ages range from 20 to 80 with mean age of 58.8 years. Three mCi (111 MBq) of 201 TlCl is used for adenosine or treadmil exercise testing and myocardial SPECT is performed utilizing low energy high resolution collimators and a triple-head camera ( MultiSPECT, Siemens medical systems, Inc., Hoffman Estate, III., USA). In addition to routine cardiac Tl-201 SPECT acquisition, included in the protocol is 1 min, anterior planar views in 128 128 matrix after stress and rest SPECT studies for evaluation of lung uptake and chamber size. Utilizing these views ECD is assessed. Five patients had focal increased activity suggesting tumor and 3 of 5 cases were confirmed as malignancy. The malignancies were thyroid cancer (Hurthle cell), lung cancer, and breast cancer. Benign lesions were autonomous thyroid nodule and pheochromocytoma. Other ECDs include pericardial effusion, pleural effusion, and paralyzed hemidiapharm.. Extracardiac disease processes such as benign or malignancy are easily detected during Tl-201 myocardial perfusion imaging using our acquisition protocol at no cost to the patients. This information could be life saving in some patients for early detection of clinically unsuspected malignancy.

  10. The Groningen hypothermic liver perfusion pump : Functional evaluation of a new machine perfusion system

    NARCIS (Netherlands)

    van der Plaats, A.; Maathuis, M. H. J.; Hart, N. A. 't; Bellekom, A. A.; Hofker, H. S.; van der Houwen, E. B.; Verkerke, G. J.; Leuvenink, H. G. D.; Verdonck, P.; Ploeg, R. J.; Rakhorst, G.

    2006-01-01

    To improve preservation of donor livers, we have developed a portable hypothermic machine perfusion (HMP) system as an alternative for static cold storage. A prototype of the system was built and evaluated on functionality. Evaluation criteria included 24 h of adequate pressure controlled perfusion,

  11. Twente Optical Perfusion Camera: system overview and performance for video rate laser Doppler perfusion imaging

    NARCIS (Netherlands)

    M. Draijer; E. Hondebrink; T. van Leeuwen; W. Steenbergen

    2009-01-01

    We present the Twente Optical Perfusion Camera (TOPCam), a novel laser Doppler Perfusion Imager based on CMOS technology. The tissue under investigation is illuminated and the resulting dynamic speckle pattern is recorded with a high speed CMOS camera. Based on an overall analysis of the signal-to-n

  12. Twente Optical Perfusion Camera: system overview and performance for video rate laser Doppler perfusion imaging

    NARCIS (Netherlands)

    Draijer, M.; Hondebrink, E.; van Leeuwen, T.; Steenbergen, W.

    2009-01-01

    We present the Twente Optical Perfusion Camera (TOPCam), a novel laser Doppler Perfusion Imager based on CMOS technology. The tissue under investigation is illuminated and the resulting dynamic speckle pattern is recorded with a high speed CMOS camera. Based on an overall analysis of the

  13. Regional cortical hyper perfusion on perfusion CT during postical motor deficit: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Baik, Hye Jin [Dept. of Radiology, Haeundae Paik Hospital, Inje University College of Medicine, Busan (Korea, Republic of)

    2013-08-15

    Postictal neurologic deficit is a well-known complication mimicking the manifestation of a stroke. We present a case of a patient with clinical evidence of Todd's paralysis correlating with reversible postictal parenchymal changes on perfusion CT and magnetic resonance (MR) imaging. In this case, perfusion CT and MR imaging were helpful in the differential diagnosis of stroke-mimicking conditions.

  14. Effects of Steroid Hormones on Sex Differences in Cerebral Perfusion.

    Science.gov (United States)

    Ghisleni, Carmen; Bollmann, Steffen; Biason-Lauber, Anna; Poil, Simon-Shlomo; Brandeis, Daniel; Martin, Ernst; Michels, Lars; Hersberger, Martin; Suckling, John; Klaver, Peter; O'Gorman, Ruth L

    2015-01-01

    Sex differences in the brain appear to play an important role in the prevalence and progression of various neuropsychiatric disorders, but to date little is known about the cerebral mechanisms underlying these differences. One widely reported finding is that women demonstrate higher cerebral perfusion than men, but the underlying cause of this difference in perfusion is not known. This study investigated the putative role of steroid hormones such as oestradiol, testosterone, and dehydroepiandrosterone sulphate (DHEAS) as underlying factors influencing cerebral perfusion. We acquired arterial spin labelling perfusion images of 36 healthy adult subjects (16 men, 20 women). Analyses on average whole brain perfusion levels included a multiple regression analysis to test for the relative impact of each hormone on the global perfusion. Additionally, voxel-based analyses were performed to investigate the sex difference in regional perfusion as well as the correlations between local perfusion and serum oestradiol, testosterone, and DHEAS concentrations. Our results replicated the known sex difference in perfusion, with women showing significantly higher global and regional perfusion. For the global perfusion, DHEAS was the only significant predictor amongst the steroid hormones, showing a strong negative correlation with cerebral perfusion. The voxel-based analyses revealed modest sex-dependent correlations between local perfusion and testosterone, in addition to a strong modulatory effect of DHEAS in cortical, subcortical, and cerebellar regions. We conclude that DHEAS in particular may play an important role as an underlying factor driving the difference in cerebral perfusion between men and women.

  15. Effects of Steroid Hormones on Sex Differences in Cerebral Perfusion.

    Directory of Open Access Journals (Sweden)

    Carmen Ghisleni

    Full Text Available Sex differences in the brain appear to play an important role in the prevalence and progression of various neuropsychiatric disorders, but to date little is known about the cerebral mechanisms underlying these differences. One widely reported finding is that women demonstrate higher cerebral perfusion than men, but the underlying cause of this difference in perfusion is not known. This study investigated the putative role of steroid hormones such as oestradiol, testosterone, and dehydroepiandrosterone sulphate (DHEAS as underlying factors influencing cerebral perfusion. We acquired arterial spin labelling perfusion images of 36 healthy adult subjects (16 men, 20 women. Analyses on average whole brain perfusion levels included a multiple regression analysis to test for the relative impact of each hormone on the global perfusion. Additionally, voxel-based analyses were performed to investigate the sex difference in regional perfusion as well as the correlations between local perfusion and serum oestradiol, testosterone, and DHEAS concentrations. Our results replicated the known sex difference in perfusion, with women showing significantly higher global and regional perfusion. For the global perfusion, DHEAS was the only significant predictor amongst the steroid hormones, showing a strong negative correlation with cerebral perfusion. The voxel-based analyses revealed modest sex-dependent correlations between local perfusion and testosterone, in addition to a strong modulatory effect of DHEAS in cortical, subcortical, and cerebellar regions. We conclude that DHEAS in particular may play an important role as an underlying factor driving the difference in cerebral perfusion between men and women.

  16. GPU-accelerated voxelwise hepatic perfusion quantification.

    Science.gov (United States)

    Wang, H; Cao, Y

    2012-09-07

    Voxelwise quantification of hepatic perfusion parameters from dynamic contrast enhanced (DCE) imaging greatly contributes to assessment of liver function in response to radiation therapy. However, the efficiency of the estimation of hepatic perfusion parameters voxel-by-voxel in the whole liver using a dual-input single-compartment model requires substantial improvement for routine clinical applications. In this paper, we utilize the parallel computation power of a graphics processing unit (GPU) to accelerate the computation, while maintaining the same accuracy as the conventional method. Using compute unified device architecture-GPU, the hepatic perfusion computations over multiple voxels are run across the GPU blocks concurrently but independently. At each voxel, nonlinear least-squares fitting the time series of the liver DCE data to the compartmental model is distributed to multiple threads in a block, and the computations of different time points are performed simultaneously and synchronically. An efficient fast Fourier transform in a block is also developed for the convolution computation in the model. The GPU computations of the voxel-by-voxel hepatic perfusion images are compared with ones by the CPU using the simulated DCE data and the experimental DCE MR images from patients. The computation speed is improved by 30 times using a NVIDIA Tesla C2050 GPU compared to a 2.67 GHz Intel Xeon CPU processor. To obtain liver perfusion maps with 626 400 voxels in a patient's liver, it takes 0.9 min with the GPU-accelerated voxelwise computation, compared to 110 min with the CPU, while both methods result in perfusion parameters differences less than 10(-6). The method will be useful for generating liver perfusion images in clinical settings.

  17. Pulmonary artery perfusion versus no pulmonary perfusion during cardiopulmonary bypass in patients with COPD

    DEFF Research Database (Denmark)

    Buggeskov, Katrine B; Sundskard, Martin M; Jonassen, Thomas

    2016-01-01

    INTRODUCTION: Absence of pulmonary perfusion during cardiopulmonary bypass (CPB) may be associated with reduced postoperative oxygenation. Effects of active pulmonary artery perfusion were explored in patients with chronic obstructive pulmonary disease (COPD) undergoing cardiac surgery. METHODS: 90...... patients were randomised to receive pulmonary artery perfusion during CPB with either oxygenated blood (n=30) or histidine-tryptophan-ketoglutarate (HTK) solution (n=29) compared with no pulmonary perfusion (n=31). The coprimary outcomes were the inverse oxygenation index compared at 21 hours after...... starting CPB and longitudinally in a mixed-effects model (MEM). Secondary outcomes were tracheal intubation time, serious adverse events, mortality, days alive outside the intensive care unit (ICU) and outside the hospital. RESULTS: 21 hours after starting CPB patients receiving pulmonary artery perfusion...

  18. The Relation Between Perfusion Pattern of Hepatic Artery Perfusion Scintigraphy and Response to Y-90 Microsphere Therapy

    Directory of Open Access Journals (Sweden)

    Bilge Volkan-Salancı

    2013-12-01

    Full Text Available Objective: Hepatic artery perfusion scintigraphy is a routine procedure for patient evaluation before Y-90 radiomicrosphere therapy and mostly used for prediction of extrahepatic leakage. Moreover, it also displays perfusion pattern of tumours, which is an important parameter on success of the therapy. The aim of this study is to assess the relation between the perfusion pattern on hepatic artery perfusion scintigraphy and radiomicrosphere therapy response. Methods: A total of 99 radiomicrosphere therapy applications were carried out in 80 patients (M/F: 55/25. Results: Heterogeneous and diffuse perfusion patterns were observed in 47 patients and 52 patients, respectively. The patients with diffuse perfusion pattern had better therapy response both on FDG PET/CT (p= 0.04 and CT (p=0.008 when compared to those with heterogenous perfusion pattern. Conclusion: Perfusion pattern observed on hepatic artery perfusion scintigraphy may be a successful predictor of early response to radiomicrosphere therapy

  19. [An automatic system controlled by microcontroller for carotid sinus perfusion].

    Science.gov (United States)

    Yi, X L; Wang, M Y; Fan, Z Z; He, R R

    2001-08-01

    To establish a new method for controlling automatically the carotid perfusion pressure. A cheap practical automatic perfusion unit based on AT89C2051 micro controller was designed. The unit, LDB-M perfusion pump and the carotid sinus of an animal constituted an automatic perfusion system. This system was able to provide ramp and stepwise updown perfusion pattern and has been used in the research of baroreflex. It can insure the precision and reproducibility of perfusion pressure curve, and improve the technical level in corresponding medical field.

  20. Perfusion harmonic imaging of the human brain

    Science.gov (United States)

    Metzler, Volker H.; Seidel, Guenter; Wiesmann, Martin; Meyer, Karsten; Aach, Til

    2003-05-01

    The fast visualisation of cerebral microcirculation supports diagnosis of acute cerebrovascular diseases. However, the commonly used CT/MRI-based methods are time consuming and, moreover, costly. Therefore we propose an alternative approach to brain perfusion imaging by means of ultrasonography. In spite of the low signal/noise-ratio of transcranial ultrasound and the high impedance of the skull, flow images of cerebral blood flow can be derived by capturing the kinetics of appropriate contrast agents by harmonic ultrasound image sequences. In this paper we propose three different methods for human brain perfusion imaging, each of which yielding flow images indicating the status of the patient's cerebral microcirculation by visualising local flow parameters. Bolus harmonic imaging (BHI) displays the flow kinetics of bolus injections, while replenishment (RHI) and diminution harmonic imaging (DHI) compute flow characteristics from contrast agent continuous infusions. RHI measures the contrast agents kinetics in the influx phase and DHI displays the diminution kinetics of the contrast agent acquired from the decay phase. In clinical studies, BHI- and RHI-parameter images were found to represent comprehensive and reproducible distributions of physiological cerebral blood flow. For DHI it is shown, that bubble destruction and hence perfusion phenomena principally can be displayed. Generally, perfusion harmonic imaging enables reliable and fast bedside imaging of human brain perfusion. Due to its cost efficiency it complements cerebrovascular diagnostics by established CT/MRI-based methods.

  1. Magnetic resonance imaging of pulmonary perfusion. Technical requirements and diagnostic impact; MRT der Lungenperfusion. Technische Voraussetzungen und diagnostischer Stellenwert

    Energy Technology Data Exchange (ETDEWEB)

    Attenberger, U.I.; Buesing, K.; Schoenberg, S.O.; Fink, C. [Klinikum Mannheim der Universitaet Heidelberg, Institut fuer Klinische Radiologie und Nuklearmedizin, Universitaetsmedizin Mannheim, Mannheim (Germany); Ingrisch, M.; Reiser, M. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Institut fuer Klinische Radiologie, Campus Grosshadern, Muenchen (Germany)

    2009-08-15

    With technical improvements in gradient hardware and the implementation of innovative k-space sampling techniques, such as parallel imaging, the feasibility of pulmonary perfusion MRI could be demonstrated in several studies. Dynamic contrast-enhanced 3D gradient echo sequences as used for time-resolved MR angiography have been established as the preferred pulse sequences for lung perfusion MRI. With these techniques perfusion of the entire lung can be visualized with a sufficiently high temporal and spatial resolution. In several trials in patients with acute pulmonary embolism, pulmonary hypertension and airway diseases, the clinical benefit and good correlation with perfusion scintigraphy have been demonstrated. The following review article describes the technical prerequisites, current post-processing techniques and the clinical indications for MR pulmonary perfusion imaging using MRI. (orig.) [German] Mit der Verfuegbarkeit leistungsfaehiger Gradientensysteme und schneller k-Raum-Akquisitionstechniken wie der parallelen Bildgebung konnten verschiedene Studien die Machbarkeit der Lungenperfusionsbildgebung in der MRT zeigen. In der Praxis haben sich dynamische kontrastverstaerkte 3D-Gradientenechosequenzen, wie sie fuer zeitaufgeloeste MR-Angiographien verwendet werden, fuer die Bildgebung der Lungenperfusion etabliert. Hiermit ist es moeglich, die Perfusion der gesamten Lunge mit ausreichend hoher zeitlicher und raeumlicher Aufloesung zu visualisieren. In mehren klinischen Studien konnte bei Patienten mit Lungenembolie, pulmonaler Hypertonie sowie Erkrankungen der Atemwege und des Lungenparenchyms der klinische Nutzen der Lungenperfusions-MRT und die gute Uebereinstimmung mit der Lungenperfusionsszintigraphie nachgewiesen werden. Der folgende Uebersichtsartikel beschreibt die technische Durchfuehrung, Bildnachverarbeitung und die klinischen Anwendungsgebiete der MRT zur Untersuchung der Lungenperfusion. (orig.)

  2. Standardized perfusion value of the esophageal carcinoma and its correlation with quantitative CT perfusion parameter values

    Energy Technology Data Exchange (ETDEWEB)

    Djuric-Stefanovic, A., E-mail: avstefan@eunet.rs [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Unit of Digestive Radiology (First University Surgical Clinic), Center of Radiology and MR, Clinical Center of Serbia, Belgrade (Serbia); Saranovic, Dj., E-mail: crvzve4@gmail.com [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Unit of Digestive Radiology (First University Surgical Clinic), Center of Radiology and MR, Clinical Center of Serbia, Belgrade (Serbia); Sobic-Saranovic, D., E-mail: dsobic2@gmail.com [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Center of Nuclear Medicine, Clinical Center of Serbia, Belgrade (Serbia); Masulovic, D., E-mail: draganmasulovic@yahoo.com [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Unit of Digestive Radiology (First University Surgical Clinic), Center of Radiology and MR, Clinical Center of Serbia, Belgrade (Serbia); Artiko, V., E-mail: veraart@beotel.rs [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Center of Nuclear Medicine, Clinical Center of Serbia, Belgrade (Serbia)

    2015-03-15

    Purpose: Standardized perfusion value (SPV) is a universal indicator of tissue perfusion, normalized to the whole-body perfusion, which was proposed to simplify, unify and allow the interchangeability among the perfusion measurements and comparison between the tumor perfusion and metabolism. The aims of our study were to assess the standardized perfusion value (SPV) of the esophageal carcinoma, and its correlation with quantitative CT perfusion measurements: blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface area product (PS) of the same tumor volume samples, which were obtained by deconvolution-based CT perfusion analysis. Methods: Forty CT perfusion studies of the esophageal cancer were analyzed, using the commercial deconvolution-based CT perfusion software (Perfusion 3.0, GE Healthcare). The SPV of the esophageal tumor and neighboring skeletal muscle were correlated with the corresponding mean tumor and muscle quantitative CT perfusion parameter values, using Spearman's rank correlation coefficient (r{sub S}). Results: Median SPV of the esophageal carcinoma (7.1; range: 2.8–13.4) significantly differed from the SPV of the skeletal muscle (median: 1.0; range: 0.4–2.4), (Z = −5.511, p < 0.001). The cut-off value of the SPV of 2.5 enabled discrimination of esophageal cancer from the skeletal muscle with sensitivity and specificity of 100%. SPV of the esophageal carcinoma significantly correlated with corresponding tumor BF (r{sub S} = 0.484, p = 0.002), BV (r{sub S} = 0.637, p < 0.001) and PS (r{sub S} = 0.432, p = 0.005), and SPV of the skeletal muscle significantly correlated with corresponding muscle BF (r{sub S} = 0.573, p < 0.001), BV (r{sub S} = 0.849, p < 0.001) and PS (r{sub S} = 0.761, p < 0.001). Conclusions: We presented a database of the SPV for the esophageal cancer and proved that SPV of the esophageal neoplasm significantly differs from the SPV of the skeletal muscle, which represented a sample of healthy

  3. Functional lung MRI in chronic obstructive pulmonary disease: comparison of T1 mapping, oxygen-enhanced T1 mapping and dynamic contrast enhanced perfusion.

    Directory of Open Access Journals (Sweden)

    Bertram J Jobst

    Full Text Available Monitoring of regional lung function in interventional COPD trials requires alternative endpoints beyond global parameters such as FEV1. T1 relaxation times of the lung might allow to draw conclusions on tissue composition, blood volume and oxygen fraction. The aim of this study was to evaluate the potential value of lung Magnetic resonance imaging (MRI with native and oxygen-enhanced T1 mapping for the assessment of COPD patients in comparison with contrast enhanced perfusion MRI.20 COPD patients (GOLD I-IV underwent a coronal 2-dimensional inversion recovery snapshot flash sequence (8 slices/lung at room air and during inhalation of pure oxygen, as well as dynamic contrast-enhanced first-pass perfusion imaging. Regional distribution of T1 at room air (T1, oxygen-induced T1 shortening (ΔT1 and peak enhancement were rated by 2 chest radiologists in consensus using a semi-quantitative 3-point scale in a zone-based approach.Abnormal T1 and ΔT1 were highly prevalent in the patient cohort. T1 and ΔT1 correlated positively with perfusion abnormalities (r = 0.81 and r = 0.80; p&0.001, and with each other (r = 0.80; p<0.001. In GOLD stages I and II ΔT1 was normal in 16/29 lung zones with mildly abnormal perfusion (15/16 with abnormal T1. The extent of T1 (r = 0.45; p<0.05, ΔT1 (r = 0.52; p<0.05 and perfusion abnormalities (r = 0.52; p<0.05 showed a moderate correlation with GOLD stage.Native and oxygen-enhanced T1 mapping correlated with lung perfusion deficits and severity of COPD. Under the assumption that T1 at room air correlates with the regional pulmonary blood pool and that oxygen-enhanced T1 reflects lung ventilation, both techniques in combination are principally suitable to characterize ventilation-perfusion imbalance. This appears valuable for the assessment of regional lung characteristics in COPD trials without administration of i.v. contrast.

  4. Using the fourth dimension to distinguish between structures for anisotropic diffusion filtering in 4D CT perfusion scans

    NARCIS (Netherlands)

    Mendrik, AM; Vonken, EPA; Witkamp, TD; Prokop, Mathias; Van Ginneken, Bram; Viergever, Max A.

    2015-01-01

    High resolution 4D (3D+time) cerebral CT perfusion (CTP) scans can be used to create 3D arteriograms (showing only arteries) and venograms (only veins). However, due to the low X-ray radiation dose used for acquiring the CTP scans, they are inherently noisy. In this paper, we propose a time intensit

  5. Whole-brain perfusion imaging with balanced steady-state free precession arterial spin labeling.

    Science.gov (United States)

    Han, Paul Kyu; Ye, Jong Chul; Kim, Eung Yeop; Choi, Seung Hong; Park, Sung-Hong

    2016-03-01

    Recently, balanced steady-state free precession (bSSFP) readout has been proposed for arterial spin labeling (ASL) perfusion imaging to reduce susceptibility artifacts at a relatively high spatial resolution and signal-to-noise ratio (SNR). However, the main limitation of bSSFP-ASL is the low spatial coverage. In this work, methods to increase the spatial coverage of bSSFP-ASL are proposed for distortion-free, high-resolution, whole-brain perfusion imaging. Three strategies of (i) segmentation, (ii) compressed sensing (CS) and (iii) a hybrid approach combining the two methods were tested to increase the spatial coverage of pseudo-continuous ASL (pCASL) with three-dimensional bSSFP readout. The spatial coverage was increased by factors of two, four and six using each of the three approaches, whilst maintaining the same total scan time (5.3 min). The number of segments and/or CS acceleration rate (R) correspondingly increased to maintain the same bSSFP readout time (1.2 s). The segmentation approach allowed whole-brain perfusion imaging for pCASL-bSSFP with no penalty in SNR and/or total scan time. The CS approach increased the spatial coverage of pCASL-bSSFP whilst maintaining the temporal resolution, with minimal impact on the image quality. The hybrid approach provided compromised effects between the two methods. Balanced SSFP-based ASL allows the acquisition of perfusion images with wide spatial coverage, high spatial resolution and SNR, and reduced susceptibility artifacts, and thus may become a good choice for clinical and neurological studies. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Magnetic resonance perfusion imaging evaluation in perfusion abnormalities of the cerebellum after supratentorial unilateral hyperacute cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    Pan Liang; Yunjun Yang; Weijian Chen; Yuxia Duan; Hongqing Wang; Xiaotong Wang

    2012-01-01

    Magnetic resonance imaging (MRI) data of 10 patients with hyperacute cerebral infarction (≤ 6 hours) were retrospectively analyzed. Six patients exhibited perfusion defects on negative enhancement integral maps, four patients exhibited perfusion differences in pseudo-color on mean time to enhance maps, and three patients exhibited perfusion differences in pseudo-color on time to minimum maps. Dynamic susceptibility contrast-enhanced perfusion weighted imaging revealed a significant increase in region negative enhancement integral in the affected hemisphere of patients with cerebral infarction. The results suggest that dynamic susceptibility contrast-enhanced perfusion weighted imaging can clearly detect perfusion abnormalities in the cerebellum after unilateral hyperacute cerebral infarction.

  7. Dynamic perfusion patterns in temporal lobe epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Dupont, Patrick; Paesschen, Wim van [KU Leuven/UZ Gasthuisberg, Nuclear Medicine, Medical Imaging Center and Neurology, Leuven (Belgium); Zaknun, John J. [International Atomic Energy Agency (IAEA), Nuclear Medicine Section, Division of Human Health, Wagramer Strasse 5, PO BOX 200, Vienna (Austria); University Hospital of Innsbruck, Department of Nuclear Medicine, Innsbruck (Austria); Maes, Alex [KU Leuven/UZ Gasthuisberg, Nuclear Medicine, Medical Imaging Center and Neurology, Leuven (Belgium); AZ Groeninge, Nuclear Medicine, Kortrijk (Belgium); Tepmongkol, Supatporn; Locharernkul, Chaichon [Chulalongkorn University, Nuclear Medicine and Neurology, Bangkok (Thailand); Vasquez, Silvia; Carpintiero, Silvina [Fleni Instituto de Investigaciones Neurologicas, Nuclear Medicine, Buenos Aires (Argentina); Bal, C.S. [All India Institute of Medical Sciences, Nuclear Medicine, New Delhi (India); Dondi, Maurizio [International Atomic Energy Agency (IAEA), Nuclear Medicine Section, Division of Human Health, Wagramer Strasse 5, PO BOX 200, Vienna (Austria); Ospedale Maggiore, Nuclear Medicine, Bologna (Italy)

    2009-05-15

    To investigate dynamic ictal perfusion changes during temporal lobe epilepsy (TLE). We investigated 37 patients with TLE by ictal and interictal SPECT. All ictal injections were performed within 60 s of seizure onset. Statistical parametric mapping was used to analyse brain perfusion changes and temporal relationships with injection time and seizure duration as covariates. The analysis revealed significant ictal hyperperfusion in the ipsilateral temporal lobe extending to subcortical regions. Hypoperfusion was observed in large extratemporal areas. There were also significant dynamic changes in several extratemporal regions: ipsilateral orbitofrontal and bilateral superior frontal gyri and the contralateral cerebellum and ipsilateral striatum. The study demonstrated early dynamic perfusion changes in extratemporal regions probably involved in both propagation of epileptic activity and initiation of inhibitory mechanisms. (orig.)

  8. Stress-only myocardial perfusion scintigraphy

    DEFF Research Database (Denmark)

    Ejlersen, June A; May, Ole; Mortensen, Jesper

    2017-01-01

    OBJECTIVE: Patients with normal stress perfusion have an excellent prognosis. Prospective studies on the diagnostic accuracy of stress-only scans with contemporary, independent examinations as gold standards are lacking. PATIENTS AND METHODS: A total of 109 patients with typical angina and no pre......OBJECTIVE: Patients with normal stress perfusion have an excellent prognosis. Prospective studies on the diagnostic accuracy of stress-only scans with contemporary, independent examinations as gold standards are lacking. PATIENTS AND METHODS: A total of 109 patients with typical angina...... and no previous coronary artery disease underwent a 2-day stress (exercise)/rest, gated, and attenuation-corrected (AC), 99m-technetium-sestamibi perfusion study, followed by invasive coronary angiography. The stress datasets were evaluated twice by four physicians with two different training levels (expert...

  9. Perfusion computed tomography for diffuse liver diseases; Perfusions-CT bei diffusen Lebererkrankungen

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, S.A.; Juchems, M.S. [Universitaetsklinikum Ulm, Klinik fuer Diagnostische und Interventionelle Radiologie, Ulm (Germany)

    2012-08-15

    Perfusion computed tomography (CT) has its main application in the clinical routine diagnosis of neuroradiological problems. Polyphase multi-detector spiral computed tomography is primarily used in liver diagnostics. The use of perfusion CT is also possible for the diagnostics and differentiation of diffuse hepatic diseases. The differentiation between cirrhosis and cirrhosis-like parenchymal changes is possible. It also helps to detect early stages of malignant tumors. However, there are some negative aspects, particularly that of radiation exposure. This paper summarizes the technical basics and possible applications of perfusion CT in cases of diffuse liver disease and weighs up the advantages and disadvantages of the examinations. (orig.) [German] Die Perfusions-CT hat ihren hauptsaechlichen Stellenwert bislang in der klinischen Routinediagnostik bei neuroradiologische Fragestellungen. In der Leberdiagnostik kommt v. a. die mehrphasige Multidetektor-Spiral-CT-Untersuchung zum Einsatz. Die Anwendung der Perfusions-CT ist auch bei der Diagnostik und Differenzierung diffuser Lebererkrankungen moeglich. Die Unterscheidung zwischen einer Leberzirrhose und zirrhoseaehnlichen Parenchymveraenderungen ist mit der Perfusions-CT moeglich. Ebenso liefert sie einen wertvollen Beitrag zur Diagnostik bei der Frueherkennung entstehender maligner Herdbefunde. Diesen Vorteilen stehen jedoch auch einige negative Aspekte gegenueber, insbesondere die relativ hohe Strahlenexposition. Die vorliegende Arbeit soll einen Ueberblick ueber die technischen Grundlagen und die Anwendungsmoeglichkeiten der Perfusions-CT bei diffusen Lebererkrankungen geben sowie die Vor- und Nachteile der Untersuchung gegeneinander abwaegen. (orig.)

  10. Is correction necessary when clinically determining quantitative cerebral perfusion parameters from multi-slice dynamic susceptibility contrast MR studies?

    Science.gov (United States)

    Salluzzi, M.; Frayne, R.; Smith, M. R.

    2006-01-01

    Several groups have modified the standard singular value decomposition (SVD) algorithm to produce delay-insensitive cerebral blood flow (CBF) estimates from dynamic susceptibility contrast (DSC) perfusion studies. However, new dependences of CBF estimates on bolus arrival times and slice position in multi-slice studies have been recently recognized. These conflicting findings can be reconciled by accounting for several experimental and algorithmic factors. Using simulation and clinical studies, the non-simultaneous measurement of arterial and tissue concentration curves (relative slice position) in a multi-slice study is shown to affect time-related perfusion parameters, e.g. arterial-tissue-delay measurements. However, the current clinical impact of relative slice position on amplitude-related perfusion parameters, e.g. CBF, can be expected to be small unless any of the following conditions are present individually or in combination: (a) high concentration curve signal-to-noise ratios, (b) small tissue mean transit times, (c) narrow arterial input functions or (d) low temporal resolution of the DSC image sequence. Recent improvements in magnetic resonance (MR) technology can easily be expected to lead to scenarios where these effects become increasingly important sources of inaccuracy for all perfusion parameter estimates. We show that using Fourier interpolated (high temporal resolution) residue functions reduces the systematic error of the perfusion parameters obtained from multi-slice studies. Preliminary results associated with this paper were presented at ISMRM 12th Scientific Meeting and Exhibition, Kyoto, Japan, 2004.

  11. Is correction necessary when clinically determining quantitative cerebral perfusion parameters from multi-slice dynamic susceptibility contrast MR studies?

    Science.gov (United States)

    Salluzzi, M; Frayne, R; Smith, M R

    2006-01-21

    Several groups have modified the standard singular value decomposition (SVD) algorithm to produce delay-insensitive cerebral blood flow (CBF) estimates from dynamic susceptibility contrast (DSC) perfusion studies. However, new dependences of CBF estimates on bolus arrival times and slice position in multi-slice studies have been recently recognized. These conflicting findings can be reconciled by accounting for several experimental and algorithmic factors. Using simulation and clinical studies, the non-simultaneous measurement of arterial and tissue concentration curves (relative slice position) in a multi-slice study is shown to affect time-related perfusion parameters, e.g. arterial-tissue-delay measurements. However, the current clinical impact of relative slice position on amplitude-related perfusion parameters, e.g. CBF, can be expected to be small unless any of the following conditions are present individually or in combination: (a) high concentration curve signal-to-noise ratios, (b) small tissue mean transit times, (c) narrow arterial input functions or (d) low temporal resolution of the DSC image sequence. Recent improvements in magnetic resonance (MR) technology can easily be expected to lead to scenarios where these effects become increasingly important sources of inaccuracy for all perfusion parameter estimates. We show that using Fourier interpolated (high temporal resolution) residue functions reduces the systematic error of the perfusion parameters obtained from multi-slice studies.

  12. Perfusion CT in acute stroke; Stellenwert der CT-Perfusion fuer die Therapie des Schlaganfalls

    Energy Technology Data Exchange (ETDEWEB)

    Eckert, Bernd [Asklepios Klinik Altona (Germany). Radiologie und Neuroradiologie; Roether, Joachim [Asklepios Klinik Altona (Germany). Neurologische Abt.; Fiehler, Jens [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Klinik und Poliklinik fuer Neuroradiologische Diagnostik und Intervention; Thomalla, Goetz [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Klinik und Poliklinik fuer Neurologie, Kopf- und Neurozentrum

    2015-06-15

    Modern multislice CT scanners enable multimodal protocols including non-enhanced CT, CT angiography, and CT perfusion. A 64-slice CT scanner provides 4-cm coverage. To cover the whole brain, a 128 - 256-slice scanner is needed. The use of perfusion CT requires an optimized scan protocol in order to reduce exposure to radiation. As compared to non-enhanced CT and CT angiography, the use of CT perfusion increases detection rates of cerebral ischemia, especially small cortical ischemic lesions, while the detection of lacunar and infratentorial stroke lesions remains limited. Perfusion CT enables estimation of collateral flow in acute occlusion of large intra- or extracranial arteries. Currently, no established reliable thresholds are available for determining infarct core and penumbral tissue by CT perfusion. Moreover, perfusion parameters depend on the processing algorithms and the software used for calculation. However, a number of studies point towards a reduction of cerebral blood volume (CBV) below 2 ml/100 g as a critical threshold that identifies infarct core. Large CBV lesions are associated with poor outcome even in the context of recanalization. The extent of early ischemic signs on non-enhanced CT remains the main parameter from CT imaging to guide acute reperfusion treatment. Nevertheless, perfusion CT increases diagnostic and therapeutic certainty in the acute setting. Similar to stroke MRI, perfusion CT enables the identification of tissue at risk of infarction by the mismatch between infarct core and the larger area of critical hypoperfusion. Further insights into the validity of perfusion parameters are expected from ongoing trials of mechanical thrombectomy in stroke.

  13. Turbo-FLASH based arterial spin labeled perfusion MRI at 7 T.

    Directory of Open Access Journals (Sweden)

    Zhentao Zuo

    Full Text Available Motivations of arterial spin labeling (ASL at ultrahigh magnetic fields include prolonged blood T1 and greater signal-to-noise ratio (SNR. However, increased B0 and B1 inhomogeneities and increased specific absorption ratio (SAR challenge practical ASL implementations. In this study, Turbo-FLASH (Fast Low Angle Shot based pulsed and pseudo-continuous ASL sequences were performed at 7T, by taking advantage of the relatively low SAR and short TE of Turbo-FLASH that minimizes susceptibility artifacts. Consistent with theoretical predictions, the experimental data showed that Turbo-FLASH based ASL yielded approximately 4 times SNR gain at 7T compared to 3T. High quality perfusion images were obtained with an in-plane spatial resolution of 0.85×1.7 mm(2. A further functional MRI study of motor cortex activation precisely located the primary motor cortex to the precentral gyrus, with the same high spatial resolution. Finally, functional connectivity between left and right motor cortices as well as supplemental motor area were demonstrated using resting state perfusion images. Turbo-FLASH based ASL is a promising approach for perfusion imaging at 7T, which could provide novel approaches to high spatiotemporal resolution fMRI and to investigate the functional connectivity of brain networks at ultrahigh field.

  14. Perfusion Quantification Using Gaussian Process Deconvolution

    DEFF Research Database (Denmark)

    Andersen, Irene Klærke; Have, Anna Szynkowiak; Rasmussen, Carl Edward

    2002-01-01

    The quantification of perfusion using dynamic susceptibility contrast MRI (DSC-MRI) requires deconvolution to obtain the residual impulse response function (IRF). In this work, a method using the Gaussian process for deconvolution (GPD) is proposed. The fact that the IRF is smooth is incorporated...... optimized according to the noise level in each voxel. The comparison is carried out using artificial data as well as data from healthy volunteers. It is shown that GPD is comparable to SVD with a variable optimized threshold when determining the maximum of the IRF, which is directly related to the perfusion...

  15. Perfusion lung imaging in the adult respiratory distress syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Pistolesi, M.; Miniati, M.; Di Ricco, G.; Marini, C.; Giuntini, C.

    1986-07-01

    In 29 perfusion lung scans (PLS) of 19 patients with ARDS, 20 of which were obtained within six days from the onset of respiratory symptoms, perfusion abnormalities were the rule. These included focal, nonsegmental defects, mostly peripheral and dorsal, and perfusion redistribution away from the dependent lung zones. PLS were scored for the presence and intensity of perfusion abnormalities and the scores of perfusion redistribution were validated against numerical indices of blood flow distribution per unit lung volume. PLS scores were correlated with arterial blood gas values, hemodynamic parameters, and chest radiographic scores of ARDS. Arterial oxygen tension correlated with the scores of both perfusion defects and redistribution. Perfusion defects correlated better with the radiographic score of ARDS, and perfusion redistribution with PAP and vascular resistance. ARDS patients exhibit peculiar patterns of PLS abnormalities not observed in other disorders. Thus, PLS may help considerably in the detection and evaluation of pulmonary vascular injury in ARDS.

  16. Improved visualization of delayed perfusion in lung MRI

    Energy Technology Data Exchange (ETDEWEB)

    Risse, Frank [Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg (Germany); Eichinger, Monika [Department of Radiology, German Cancer Research Center, Heidelberg (Germany); Kauczor, Hans-Ulrich [Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg (Germany); Semmler, Wolfhard [Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg (Germany); Puderbach, Michael, E-mail: m.puderbach@dkfz.de [Department of Radiology, German Cancer Research Center, Heidelberg (Germany)

    2011-01-15

    Introduction: The investigation of pulmonary perfusion by three-dimensional (3D) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was proposed recently. Subtraction images are generated for clinical evaluation, but temporal information is lost and perfusion defects might therefore be masked in this process. The aim of this study is to demonstrate a simple analysis strategy and classification for 3D-DCE-MRI perfusion datasets in the lung without omitting the temporal information. Materials and methods: Pulmonary perfusion measurements were performed in patients with different lung diseases using a 1.5 T MR-scanner with a time-resolved 3D-GRE pulse sequence. 25 3D-volumes were acquired after iv-injection of 0.1 mmol/kg KG Gadolinium-DTPA. Three parameters were determined for each pixel: (1) peak enhancement S{sub n,max} normalized to the arterial input function to detect regions of reduced perfusion; (2) time between arterial peak enhancement in the large pulmonary artery and tissue peak enhancement {tau} to visualize regions with delayed bolus onset; and (3) ratio R = S{sub n,max}/{tau} was calculated to visualize impaired perfusion, irrespectively of whether related to reduced or delayed perfusion. Results: A manual selection of peak perfusion images is not required. Five different types of perfusion can be found: (1) normal perfusion; (2) delayed non-reduced perfusion; (3) reduced non-delayed perfusion; (4) reduced and delayed perfusion; and (5) no perfusion. Types II and IV could not be seen in subtraction images since the temporal information is necessary for this purpose. Conclusions: The analysis strategy in this study allows for a simple and observer-independent visualization and classification of impaired perfusion in dynamic contrast-enhanced pulmonary perfusion MRI by using the temporal information of the datasets.

  17. [Design of the Rolling Type Nasal Feeding Perfusion Apparatus].

    Science.gov (United States)

    Yu, Dong; Yang, Yonghuan; Hu, Huiqin; Luo, Hongjun; Feng, Yunhao; Hao, Xiali

    2015-09-01

    At present, the existing problem in nasal feeding perfusion apparatus is laborious and instability. Designing the rolling type perfusion apparatus by using a roller pump, the problem is solved. Compared with the traditional perfusion apparatus, the advantage lies in liquid carrying only need once and simulating human swallowing process. Through testing and verification, the apparatus can be used in nasal feeding perfusion for elderly or patients.

  18. Experimental evaluation and computational modeling of tissue damage from low-flow push-pull perfusion sampling in vivo.

    Science.gov (United States)

    Cepeda, David E; Hains, Leah; Li, David; Bull, Joseph; Lentz, Stephen I; Kennedy, Robert T

    2015-03-15

    Neurochemical monitoring via sampling probes is valuable for deciphering neurotransmission in vivo. Microdialysis is commonly used; however, the spatial resolution is poor. Recently push-pull perfusion at low flow rates (50nL/min) has been proposed as a method for in vivo sampling from the central nervous system. Tissue damage from such probes has not been investigated in detail. In this work, we evaluated acute tissue response to low-flow push-pull perfusion by infusing the nuclear stains Sytox Orange and Hoechst 33342 through probes implanted in the striatum for 200min, to label damaged and total cells, respectively, in situ. Using the damaged/total labeled cell ratio as a measure of tissue damage, we found that 33±8% were damaged within the dye region around a microdialysis probe. We found that low-flow push-pull perfusion probes damaged 24±4% of cells in the sampling area. Flow had no effect on the number of damaged cells for low-flow push-pull perfusion. Modeling revealed that shear stress and pressure gradients generated by the flow were lower than thresholds expected to cause damage. Comparison with existing methods.Push-pull perfusion caused less tissue damage but yielded 1500-fold better spatial resolution. Push-pull perfusion at low flow rates is a viable method for sampling from the brain with potential for high temporal and spatial resolution. Tissue damage is mostly caused by probe insertion. Smaller probes may yield even lower damage. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Perfusion MRI in neuro-psychiatric systemic lupus erthemathosus.

    NARCIS (Netherlands)

    Emmer, B.J.; Osch, M.J. van; Wu, O.; Steup-Beekman, G.M.; Steens, S.; Huizinga, T.W.J.; Buchem, M.A. van; Grond, J. van der

    2010-01-01

    PURPOSE: To use perfusion weighted MR to quantify any perfusion abnormalities and to determine their contribution to neuropsychiatric (NP) involvement in systemic lupus erythematosus (SLE). MATERIALS AND METHODS: We applied dynamic susceptibility contrast (DSC) perfusion MRI in 15 active NPSLE, 26 i

  20. Computed tomography perfusion evaluation after extracranial-intracranial bypass surgery

    NARCIS (Netherlands)

    Vos, P.C.; Riordan, A.J.; Smit, E.J.; Jong, H.W. de; Zwan, A. van der; Velthuis, B.K.; Viergever, M.A.; Dankbaar, J.W.

    2015-01-01

    OBJECTIVE: Perfusion imaging is increasingly used for postoperative evaluation of extracranial to intracranial (EC-IC) bypass surgery. Altered hemodynamics and delayed arrival of the contrast agent in the area fed by the bypass can influence perfusion measurement. We compared perfusion asymmetry obt

  1. An alternative method for neonatal cerebro-myocardial perfusion

    Science.gov (United States)

    Luciani, Giovanni Battista; De Rita, Fabrizio; Faggian, Giuseppe; Mazzucco, Alessandro

    2012-01-01

    Several techniques have already been described for selective cerebral perfusion during repair of aortic arch pathology in children. One method combining cerebral with myocardial perfusion has also been proposed. A novel technique is reported here for selective and independent cerebro-myocardial perfusion for neonatal and infant arch surgery. Technical aspects and potential advantages are discussed. PMID:22307393

  2. CT angiography and CT perfusion in acute ischemic stroke

    NARCIS (Netherlands)

    Seeters, T. van

    2016-01-01

    CT angiography and CT perfusion are used in patients with acute ischemic stroke for diagnostic purposes and to select patients for treatment. In this thesis, the reproducibility of CT angiography and CT perfusion is examined, the additional value of CT angiography and CT perfusion for stroke outcome

  3. Computed tomography perfusion evaluation after extracranial-intracranial bypass surgery

    NARCIS (Netherlands)

    Vos, Pieter C.; Riordan, Alan J.; Smit, Ewoud J.; de Jong, Hugo W. A. M.; van der Zwan, Albert; Velthuis, BK; Viergever, Max A.; Dankbaar, Jan Willem

    2015-01-01

    Objective: Perfusion imaging is increasingly used for postoperative evaluation of extracranial to intracranial (EC-IC) bypass surgery. Altered hemodynamics and delayed arrival of the contrast agent in the area fed by the bypass can influence perfusion measurement. We compared perfusion asymmetry obt

  4. Low-dose 4D myocardial perfusion with x-ray micro-CT

    Science.gov (United States)

    Clark, D. P.; Badea, C. T.

    2017-03-01

    X-ray CT is widely used, both clinically and pre-clinically, for fast, high-resolution, anatomic imaging; however, compelling opportunities exist to expand its use in functional imaging applications. For instance, temporally-resolved CT data can detail cardiac motion and blood flow dynamics for one-stop cardiovascular CT imaging procedures. In previous work, we demonstrated efficient, low-dose projection acquisition and reconstruction strategies for cardiac micro-CT imaging and for multiple-injection micro-CT perfusion imaging. Here, we extend this previous work with regularization based on rank-sparse kernel regression and on filtration with the Karhunen-Loeve transform. Using a dual source, prospectively gated sampling strategy which produces an approximately uniform distribution of projections, we apply this revised algorithm to the assessment of both myocardial perfusion and cardiac functional metrics from the same set of projection data. We test the algorithm in simulations using a modified version of the MOBY mouse phantom which contains realistic perfusion and cardiac dynamics. The proposed algorithm reduces the reconstruction error by 81% relative to unregularized, algebraic reconstruction. The results confirm our ability to simultaneously solve for cardiac temporal motion and perfusion dynamics. In future work, we will apply the algorithm and sampling protocol to small animal cardiac studies.

  5. Evaluation of Rigid-Body Motion Compensation in Cardiac Perfusion SPECT Employing Polar-Map Quantification.

    Science.gov (United States)

    Pretorius, P Hendrik; Johnson, Karen L; King, Michael A

    2016-06-01

    We have recently been successful in the development and testing of rigid-body motion tracking, estimation and compensation for cardiac perfusion SPECT based on a visual tracking system (VTS). The goal of this study was to evaluate in patients the effectiveness of our rigid-body motion compensation strategy. Sixty-four patient volunteers were asked to remain motionless or execute some predefined body motion during an additional second stress perfusion acquisition. Acquisitions were performed using the standard clinical protocol with 64 projections acquired through 180 degrees. All data were reconstructed with an ordered-subsets expectation-maximization (OSEM) algorithm using 4 projections per subset and 5 iterations. All physical degradation factors were addressed (attenuation, scatter, and distance dependent resolution), while a 3-dimensional Gaussian rotator was used during reconstruction to correct for six-degree-of-freedom (6-DOF) rigid-body motion estimated by the VTS. Polar map quantification was employed to evaluate compensation techniques. In 54.7% of the uncorrected second stress studies there was a statistically significant difference in the polar maps, and in 45.3% this made a difference in the interpretation of segmental perfusion. Motion correction reduced the impact of motion such that with it 32.8 % of the polar maps were statistically significantly different, and in 14.1% this difference changed the interpretation of segmental perfusion. The improvement shown in polar map quantitation translated to visually improved uniformity of the SPECT slices.

  6. Pulmonary artery perfusion versus no pulmonary perfusion during cardiopulmonary bypass in patients with COPD

    DEFF Research Database (Denmark)

    Buggeskov, Katrine B; Sundskard, Martin M; Jonassen, Thomas;

    2016-01-01

    INTRODUCTION: Absence of pulmonary perfusion during cardiopulmonary bypass (CPB) may be associated with reduced postoperative oxygenation. Effects of active pulmonary artery perfusion were explored in patients with chronic obstructive pulmonary disease (COPD) undergoing cardiac surgery. METHODS: 90...... starting CPB and longitudinally in a mixed-effects model (MEM). Secondary outcomes were tracheal intubation time, serious adverse events, mortality, days alive outside the intensive care unit (ICU) and outside the hospital. RESULTS: 21 hours after starting CPB patients receiving pulmonary artery perfusion...... with normothermic oxygenated blood had a higher oxygenation index compared with no pulmonary perfusion (mean difference (MD) 0.94; 95% CI 0.05 to 1.83; p=0.04). The blood group had also a higher oxygenation index both longitudinally (MEM, p=0.009) and at 21 hours (MD 0.99; CI 0.29 to 1.69; p=0.007) compared...

  7. Development of a Phantom Tissue for Blood Perfusion Measurements and Noninvasive Blood Perfusion Estimation in Living Tissue

    OpenAIRE

    Mudaliar, Ashvinikumar

    2007-01-01

    A convenient method for testing and calibrating surface perfusion sensors has been developed. A phantom tissue model is used to mimic the non-directional blood flow of tissue perfusion. A computational fluid dynamics (CFD) model was constructed in Fluent to design the phantom tissue and validate the experimental results. The phantom perfusion system was used with a perfusion sensor based on the clearance of thermal energy. A heat flux gage measures the heat flux response of tissue whe...

  8. Fast Registration of Cardiac Perfusion MRI

    DEFF Research Database (Denmark)

    Stegmann, Mikkel Bille; Larsson, Henrik B. W.

    2003-01-01

    This abstract presents a novel method for registration of cardiac perfusion MRI sequences. By performing complex analyses of variance and clustering in an annotated training set off-line, our method provides real-time segmentation in an on-line setting. This renders the method feasible for live...

  9. Nonrigid registration of myocardial perfusion MRI

    DEFF Research Database (Denmark)

    Ólafsdóttir, Hildur

    2005-01-01

    This paper describes a fully automatic registration of 10 multi-slice myocardial perfusion magnetic resonance image sequences. The registration of these sequences is crucial for the clinical interpretation, which currently is subjected to manual labour. The approach used in this study is a nonrig...

  10. Leukocytes and Perfusion Recovery after Arterial Occlusion

    NARCIS (Netherlands)

    Haverslag, R.T.

    2012-01-01

    The main topic of this thesis is arteriogenesis and the role circulating leukocytes play in this process of perfusion recovery. We have used clinically applicable inhibitors to increase leukocyte attraction and extravasation and discovered previously unknown factors which play a role in

  11. Methodology for ventilation/perfusion SPECT

    DEFF Research Database (Denmark)

    Bajc, Marika; Neilly, Brian; Miniati, Massimo

    2010-01-01

    Ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) is the scintigraphic technique of choice for the diagnosis of pulmonary embolism and many other disorders that affect lung function. Data from recent ventilation studies show that the theoretic advantages of Technegas ov...

  12. Study of lung perfusion in colagenosis

    Energy Technology Data Exchange (ETDEWEB)

    Macedo de Carvalho, A.C.; Calegaro, J.U.M. (Fundacao Hospitalar do Distrito Federal, Distrito Federal (Brazil). Unidade de Medicina Nuclear)

    1982-07-01

    The lung involvement in the various types of colagenosis has been widely described in the literature. However, the study of lung perfusion utilizing radionuclides has been only mentioned in a few papers. With the intention of ascertaining the importance of the lung perfusion scanning in colagenosis, ten cases were studied, seven of which were females and three males, with the following pathologies: 4 rheumatoid arthritis, 4 systemic lupus eritematosous, 1 scleroderma and 1 scleroderma plus dermatomyositis. The ages of the patients varied from 20 to 73 years, and the duration of the disease from 1 month to 39 years. The lung scanning showed perfusion defects in 100% of the cases, not related with the type of colagenosis, duration of the disease, sex or age. On the other hand, the X rays study showed alterations in only 2 patients (20% of the cases). The ventilatory and respiratory functions were tested on 7 patients showing alteration (mixed pattern with predominance of the restrictive factor) in only one (14.3%), while the other patients were normal (85.7%). The importance of the lung perfusion scanning study in all patients with collagen vascular diseases is emphasized.

  13. Simultaneous Multiagent Hyperpolarized 13C Perfusion Imaging

    DEFF Research Database (Denmark)

    von Morze, Cornelius; Bok, Robert A.; Reed, Galen D.

    2014-01-01

    Purpose: To demonstrate simultaneous hyperpolarization and imaging of three 13C-labeled perfusion MRI contrast agents with dissimilar molecular structures ([13C]urea, [13C]hydroxymethyl cyclopropane, and [13C]t-butanol) and correspondingly variable chemical shifts and physiological characteristic...

  14. Simplified prototyping of perfusable polystyrene microfluidics

    Science.gov (United States)

    Tran, Reginald; Ahn, Byungwook; R. Myers, David; Qiu, Yongzhi; Sakurai, Yumiko; Moot, Robert; Mihevc, Emma; Trent Spencer, H.; Doering, Christopher; A. Lam, Wilbur

    2014-01-01

    Cell culture in microfluidic systems has primarily been conducted in devices comprised of polydimethylsiloxane (PDMS) or other elastomers. As polystyrene (PS) is the most characterized and commonly used substrate material for cell culture, microfluidic cell culture would ideally be conducted in PS-based microsystems that also enable tight control of perfusion and hydrodynamic conditions, which are especially important for culture of vascular cell types. Here, we report a simple method to prototype perfusable PS microfluidics for endothelial cell culture under flow that can be fabricated using standard lithography and wet laboratory equipment to enable stable perfusion at shear stresses up to 300 dyn/cm2 and pumping pressures up to 26 kPa for at least 100 h. This technique can also be extended to fabricate perfusable hybrid PS-PDMS microfluidics of which one application is for increased efficiency of viral transduction in non-adherent suspension cells by leveraging the high surface area to volume ratio of microfluidics and adhesion molecules that are optimized for PS substrates. These biologically compatible microfluidic devices can be made more accessible to biological-based laboratories through the outsourcing of lithography to various available microfluidic foundries. PMID:25379106

  15. Nuclear cardiology: Myocardial perfusion and function

    Energy Technology Data Exchange (ETDEWEB)

    Seldin, D.W. (Lahey Clinic Medical Center, Burlington, MA (United States))

    1991-08-01

    Myocardial perfusion studies continue to be a major focus of research, with new investigations of the relationship of exercise-redistribution thallium imaging to diagnosis, prognosis, and case management. The redistribution phenomenon, which seemed to be fairly well understood a few years ago, is now recognized to be much more complex than originally thought, and various strategies have been proposed to clarify the meaning of persistent defects. Pharmacologic intervention with dipyridamole and adenosine has become available as an alternative to exercise, and comparisons with exercise imaging and catheterization results have been described. Thallium itself is no longer the sole single-photon perfusion radiopharmaceutical; two new technetium agents are now widely available. In addition to perfusion studies, advances in the study of ventricular function have been made, including reports of studies performed in conjunction with technetium perfusion studies, new insights into cardiac physiology, and the prognostic and case-management information that function studies provide. Finally, work has continued with monoclonal antibodies for the identification of areas of myocyte necrosis. 41 references.

  16. Clinical application of hepatic CT perfusion

    Institute of Scientific and Technical Information of China (English)

    Liang Zhong; Wen-Jing Wang; Jian-Rong Xu

    2009-01-01

    Complicated changes occur in hemodynamics of hepatic artery and vein, and portal vein under various kinds of pathologic status because of distinct double hepatic blood supply. This article reviews the clinical application of hepatic computed tomography perfusion in some liver diseases.

  17. Asynchronicity of facial blood perfusion in migraine.

    Directory of Open Access Journals (Sweden)

    Nina Zaproudina

    Full Text Available Asymmetrical changes in blood perfusion and asynchronous blood supply to head tissues likely contribute to migraine pathophysiology. Imaging was widely used in order to understand hemodynamic variations in migraine. However, mapping of blood pulsations in the face of migraineurs has not been performed so far. We used the Blood Pulsation Imaging (BPI technique, which was recently developed in our group, to establish whether 2D-imaging of blood pulsations parameters can reveal new biomarkers of migraine. BPI characteristics were measured in migraineurs during the attack-free interval and compared to healthy subjects with and without a family history of migraine. We found a novel phenomenon of transverse waves of facial blood perfusion in migraineurs in contrast to healthy subjects who showed synchronous blood delivery to both sides of the face. Moreover, the amplitude of blood pulsations was symmetrically distributed over the face of healthy subjects, but asymmetrically in migraineurs and subjects with a family history of migraine. In the migraine patients we found a remarkable correlation between the side of unilateral headache and the direction of the blood perfusion wave. Our data suggest that migraine is associated with lateralization of blood perfusion and asynchronous blood pulsations in the facial area, which could be due to essential dysfunction of the autonomic vascular control in the face. These findings may further enhance our understanding of migraine pathophysiology and suggest new easily available biomarkers of this pathology.

  18. Asynchronicity of facial blood perfusion in migraine.

    Science.gov (United States)

    Zaproudina, Nina; Teplov, Victor; Nippolainen, Ervin; Lipponen, Jukka A; Kamshilin, Alexei A; Närhi, Matti; Karjalainen, Pasi A; Giniatullin, Rashid

    2013-01-01

    Asymmetrical changes in blood perfusion and asynchronous blood supply to head tissues likely contribute to migraine pathophysiology. Imaging was widely used in order to understand hemodynamic variations in migraine. However, mapping of blood pulsations in the face of migraineurs has not been performed so far. We used the Blood Pulsation Imaging (BPI) technique, which was recently developed in our group, to establish whether 2D-imaging of blood pulsations parameters can reveal new biomarkers of migraine. BPI characteristics were measured in migraineurs during the attack-free interval and compared to healthy subjects with and without a family history of migraine. We found a novel phenomenon of transverse waves of facial blood perfusion in migraineurs in contrast to healthy subjects who showed synchronous blood delivery to both sides of the face. Moreover, the amplitude of blood pulsations was symmetrically distributed over the face of healthy subjects, but asymmetrically in migraineurs and subjects with a family history of migraine. In the migraine patients we found a remarkable correlation between the side of unilateral headache and the direction of the blood perfusion wave. Our data suggest that migraine is associated with lateralization of blood perfusion and asynchronous blood pulsations in the facial area, which could be due to essential dysfunction of the autonomic vascular control in the face. These findings may further enhance our understanding of migraine pathophysiology and suggest new easily available biomarkers of this pathology.

  19. Perfusion CT in Colorectal Cancer: Comparison of Perfusion Parameters with Tumor Grade and Microvessel Density

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Woong; Jeong, Yong Yeon; Chang, Nam Kyu; Heo, Suk Hee; Hur, Young Hoe; Kang, Heoung Keun [Chonnam National University Hwasun Hospital, Hwasun(Korea, Republic of); Shin, Sang Soo; Lee, Jae Hyuk [Chonnam National University Hospital, Gwangju (Korea, Republic of)

    2012-02-15

    The purpose of this study was to prospectively compare pre-operative computed tomography (CT) perfusion parameters with tumor grade from colorectal adenocarcinoma (CRC) and to correlate pre-operative CT perfusion parameters with microvessel density (MVD) to evaluate angiogenesis in CRC. Pre-operative perfusion CTs were performed with a 64-channel multidetector row CT in 27 patients (17 women and 10 men; age range 32-82 years) who were diagnosed with CRC involving the sigmoid and rectum between August 2006 and November 2007. All patients underwent surgery without pre-operative chemotherapy or radiation therapy. Dynamic perfusion CTs were performed for 65 seconds after intravenous injection of contrast medium (100 mL, 300 mg of iodine per mL, 5 mL/sec). Before surgery, blood flow (BF), blood volume, mean transit time (MTT), and permeability-surface area product were measured in the tumor. After surgery, one gastrointestinal pathologist evaluated tumor grade and performed immunohistochemical staining using CD 34 to determine MVD in each tumor. The Kruskal-Wallis test was used to compare CT perfusion parameters with tumor grade, and Pearson's correlation analysis was used to correlate CT perfusion parameters with MVD. In 27 patients with CRC, tumor grading was as follows: well differentiated (n = 8); moderately differentiated (n = 15); and poorly differentiated (n = 4). BF was higher in moderately differentiated CRC than well differentiated and poorly differentiated CRCs (p = 0.14). MTT was shorter in moderately differentiated than well differentiated and poorly differentiated CRCs (p = 0.039). The MVD was greater in poorly differentiated than well differentiated and moderately differentiated CRCs (p = 0.034). There was no significant correlation between other perfusion parameters and tumor grade. There was no significant correlation between CT perfusion parameters and MVD. BF and MTT measurement by perfusion CT is effective in predicting moderately differentiated CRCs

  20. Volume perfusion CT imaging of cerebral vasospasm: diagnostic performance of different perfusion maps

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Ahmed E. [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Eberhard Karls University Tuebingen, University Hospital Tuebingen, Department for Diagnostic and Interventional Radiology, Tuebingen (Germany); Afat, Saif; Nikoubashman, Omid; Mueller, Marguerite; Wiesmann, Martin; Brockmann, Carolin [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Schubert, Gerrit Alexander [RWTH Aachen University, Department of Neurosurgery, Aachen (Germany); Bier, Georg [Eberhard Karls University Tuebingen, University Hospital Tuebingen, Department for Diagnostic and Interventional Neuroradiology, Tuebingen (Germany); Brockmann, Marc A. [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); University Hospital Mainz, Department of Neuroradiology, Mainz (Germany)

    2016-08-15

    In this study, we aimed to evaluate the diagnostic performance of different volume perfusion CT (VPCT) maps regarding the detection of cerebral vasospasm compared to angiographic findings. Forty-one datasets of 26 patients (57.5 ± 10.8 years, 18 F) with subarachnoid hemorrhage and suspected cerebral vasospasm, who underwent VPCT and angiography within 6 h, were included. Two neuroradiologists independently evaluated the presence and severity of vasospasm on perfusion maps on a 3-point Likert scale (0 - no vasospasm, 1 - vasospasm affecting <50 %, 2 - vasospasm affecting >50 % of vascular territory). A third neuroradiologist independently assessed angiography for the presence and severity of vasospasm on a 3-point Likert scale (0 - no vasospasm, 1 - vasospasm affecting < 50 %, 2 - vasospasm affecting > 50 % of vessel diameter). Perfusion maps of cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and time to drain (TTD) were evaluated regarding diagnostic accuracy for cerebral vasospasm with angiography as reference standard. Correlation analysis of vasospasm severity on perfusion maps and angiographic images was performed. Furthermore, inter-reader agreement was assessed regarding findings on perfusion maps. Diagnostic accuracy for TTD and MTT was significantly higher than for all other perfusion maps (TTD, AUC = 0.832; MTT, AUC = 0.791; p < 0.001). TTD revealed higher sensitivity than MTT (p = 0.007). The severity of vasospasm on TTD maps showed significantly higher correlation levels with angiography than all other perfusion maps (p ≤ 0.048). Inter-reader agreement was (almost) perfect for all perfusion maps (kappa ≥ 0.927). The results of this study indicate that TTD maps have the highest sensitivity for the detection of cerebral vasospasm and highest correlation with angiography regarding the severity of vasospasm. (orig.)

  1. Performance evaluation of a pinhole SPECT system for myocardial perfusion imaging of mice.

    Science.gov (United States)

    Wu, Max C; Hasegawa, Bruce H; Dae, Michael W

    2002-12-01

    The increasing use of transgenic mice as models of human physiology and disease has motivated the development of dedicated in vivo imaging systems for anatomic and functional characterization of mice as an adjunct to or a replacement for established ex vivo techniques. We have developed a pinhole single photon emission computed tomography (SPECT) system for high resolution imaging of mice with cardiovascular imaging as the primary application. In this work, we characterize the system performance through phantom studies. The spatial resolution and sensitivity were measured from images of a line source and point source, respectively, and were reported for a range of object-to-pinhole distances and pinhole diameters. Tomographic images of a uniform cylindrical phantom, Defrise phantom, and grid phantom were used to characterize the image uniformity and spatial linearity. The uniform phantom image did not contain any ring or reconstruction artifacts, but blurring in the axial direction was evident in the Defrise phantom images. The grid phantom images demonstrated excellent spatial linearity. A novel phantom modeling perfusion of the left ventricle of a mouse was designed and built with perfusion defects of varying sizes to evaluate the system performance for myocardial perfusion imaging of mice. The defect volumes were measured from the pinhole SPECT images and correlated to the actual defect volumes calculated according to geometric formulas. Linear regression analysis produced a correlation coefficient of r = 0.995 (p defect size in mice using pinhole SPECT. We have performed phantom studies to characterize the spatial resolution, sensitivity, image uniformity, and spatial linearity of the pinhole SPECT system. Measurement of the perfusion defect size is a valuable phenotypic assessment and will be useful for hypothesis testing in murine models of cardiovascular disease.

  2. Ventilation-perfusion distribution in normal subjects.

    Science.gov (United States)

    Beck, Kenneth C; Johnson, Bruce D; Olson, Thomas P; Wilson, Theodore A

    2012-09-01

    Functional values of LogSD of the ventilation distribution (σ(V)) have been reported previously, but functional values of LogSD of the perfusion distribution (σ(q)) and the coefficient of correlation between ventilation and perfusion (ρ) have not been measured in humans. Here, we report values for σ(V), σ(q), and ρ obtained from wash-in data for three gases, helium and two soluble gases, acetylene and dimethyl ether. Normal subjects inspired gas containing the test gases, and the concentrations of the gases at end-expiration during the first 10 breaths were measured with the subjects at rest and at increasing levels of exercise. The regional distribution of ventilation and perfusion was described by a bivariate log-normal distribution with parameters σ(V), σ(q), and ρ, and these parameters were evaluated by matching the values of expired gas concentrations calculated for this distribution to the measured values. Values of cardiac output and LogSD ventilation/perfusion (Va/Q) were obtained. At rest, σ(q) is high (1.08 ± 0.12). With the onset of ventilation, σ(q) decreases to 0.85 ± 0.09 but remains higher than σ(V) (0.43 ± 0.09) at all exercise levels. Rho increases to 0.87 ± 0.07, and the value of LogSD Va/Q for light and moderate exercise is primarily the result of the difference between the magnitudes of σ(q) and σ(V). With known values for the parameters, the bivariate distribution describes the comprehensive distribution of ventilation and perfusion that underlies the distribution of the Va/Q ratio.

  3. A model system for perfusion quantification using FAIR

    DEFF Research Database (Denmark)

    Andersen, Irene Klærke; Sidaros, Karam; Gesmar, Henrik

    2000-01-01

    Flow-sensitive experiments (FAIR) have been performed on a tube-flow phantom in order to validate quantitative perfusion measurements on humans. A straight-forward correspondence between perfusion and bulk-flow is found. It is shown that the flow phantom model only holds when the slice profiles...... to perfusion values lower than the cortical perfusion in the brain. Thus, the experimental accuracy and the computational methods for quantitative perfusion measurements in vivo can be validated by a tube-flow phantom....

  4. A model system for perfusion quantification using FAIR

    DEFF Research Database (Denmark)

    Andersen, I.K.; Sidaros, Karam; Gesmar, H

    2000-01-01

    Flow-sensitive experiments (FAIR) have been performed on a tube-flow phantom in order to validate quantitative perfusion measurements on humans. A straight-forward correspondence between perfusion and bulk-flow is found. It is shown that the flow phantom model only holds when the slice profiles...... to perfusion values lower than the cortical perfusion in the brain. Thus, the experimental accuracy and the computational methods for quantitative perfusion measurements in vivo can be validated by a tube-flow phantom...

  5. Computational Fluid Dynamics Simulations of Contrast Agent Bolus Dispersion in a Coronary Bifurcation: Impact on MRI-Based Quantification of Myocardial Perfusion

    Directory of Open Access Journals (Sweden)

    Regine Schmidt

    2013-01-01

    Full Text Available Contrast-enhanced first-pass magnetic resonance imaging (MRI in combination with a tracer kinetic model, for example, MMID4, can be used to determine myocardial blood flow (MBF and myocardial perfusion reserve (MPR. Typically, the arterial input function (AIF required for this methodology is estimated from the left ventricle (LV. Dispersion of the contrast agent bolus might occur between the LV and the myocardial tissue. Negligence of bolus dispersion could cause an error in MBF determination. The aim of this study was to investigate the influence of bolus dispersion in a simplified coronary bifurcation geometry including one healthy and one stenotic branch on the quantification of MBF and MPR. Computational fluid dynamics (CFD simulations were combined with MMID4. Different inlet boundary conditions describing pulsatile and constant flows for rest and hyperemia and differing outflow conditions have been investigated. In the bifurcation region, the increase of the dispersion was smaller than inside the straight vessels. A systematic underestimation of MBF values up to −16.1% for pulsatile flow and an overestimation of MPR up to 7.5% were found. It was shown that, under the conditions considered in this study, bolus dispersion can significantly influence the results of quantitative myocardial MR-perfusion measurements.

  6. Perfusion magnetic resonance imaging with continuous arterial spin labeling: methods and clinical applications in the central nervous system

    Energy Technology Data Exchange (ETDEWEB)

    Detre, John A. E-mail: detre@mail.med.upenn.edu; Alsop, David C

    1999-05-01

    for CASL perfusion MRI, while increasing the slice coverage, resolution and stability of the images. These techniques have a broad range of potential applications in clinical and basic research of brain physiology, as well as in other organs.

  7. SU-E-QI-06: Design and Initial Validation of a Precise Capillary Phantom to Test Perfusion Systems

    Energy Technology Data Exchange (ETDEWEB)

    Wood, R; Iacobucci, G; Khobragade, P; Ying, L; Snyder, K; Wack, D; Rudin, S; Ionita, C [University at Buffalo, Buffalo, NY (United States)

    2014-06-15

    Purpose: To design a precise perfusion phantom mimicking capillaries of the brain vasculature which could be used to test various perfusion protocols and algorithms which generate perfusion maps. Methods: A perfusion phantom was designed in Solidworks and built using additive manufacturing. The phantom was an overall cylindrical shape of diameter and height 20mm and containing capillaries of 200μm or 300μm which were parallel and in contact making up the inside volume where flow was allowed. We created a flow loop using a peristaltic pump and contrast agent was injected manually. Digital Subtraction Angiographic images and low contrast images with cone beam CT were acquired after the contrast was injected. These images were analyzed by our own code in LabVIEW software and Time-Density Curve, MTT and TTP was calculated. Results: Perfused area was visible in the cone beam CT images; however, individual capillaries were not distinguishable. The Time-Density Curve acquired was accurate, sensitive and repeatable. The parameters MTT, and TTP offered by the phantom were very sensitive to slight changes in the TDC shape. Conclusion: We have created a robust calibrating model for evaluation of existing perfusion data analysis systems. This approach is extremely sensitive to changes in the flow due to the high temporal resolution and could be used as a golden standard to assist developers in calibrating and testing of imaging perfusion systems and software algorithms. Supported by NIH Grant: 2R01EB002873 and an equipment grant from Toshiba Medical Systems Corporation.

  8. Diffusion-weighted MRI, dynamic susceptibility contrast MRI and ultrasound perfusion quantification of denervated muscle in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Goyault, G.; Beregi, J.P. [University Hospital, Department of Cardiovascular imaging, Cardiologic Hospital, Lille (France); Bierry, G.; Holl, N.; Dietemann, J.L.; Kremer, S. [University Hospital, Department of Neuroradiology, Strasbourg (France); Lhermitte, B. [University Hospital, Department of Pathology, Strasbourg (France)

    2012-01-15

    The purpose of this study was to assess denervated muscle perfusion using dynamic susceptibility contrast MRI (DSCMRI) and contrast-enhanced ultrasound (CEUS), and to measure denervated muscle apparent diffusion coefficient (ADC) on b1000 diffusion-weighted MRI (DWMRI) at 3 T in order to clarify whether muscle denervation leads to an increase in the extracellular extravascular space, or an increase in blood flow - or both. Axotomy of the right sciatic nerve of six white rabbits was performed at day 0. At day 9, hind limb muscles MRI and CEUS were performed to assess the consequences of denervation and both semimembranosus muscles of each rabbit were explanted for histological studies. Signal intensity on T2- and T1-weighted MRI, ADC on DWMRI, maximum signal drop (MSD) on DSCMRI and the area under the curve (AUC) on CEUS were measured over circular regions of interest (ROI), in both semimembranosus muscles. Non-parametric Wilcoxon matched-pairs tests were used to assess the mean differences between denervated and normal muscles. T2 fat-saturated (FS) MRI studies showed a strong signal in the right semimembranosus muscles compared with the left side, and gadolinium enhancement was observed on T1 FS MRI. Denervated muscles show a significant increase in ADC on DWMRI (p < 0.01) and a significant signal enhancement on DSCMR imaging (p < 0.05) and on first-pass CEUS (p < 0.05). The results of this study - based on perfusion- and diffusion-weighted images - suggest that, after denervation, both increased blood flow through muscle tissue and expansion of the extracellular water volume are present. (orig.)

  9. Hepatic perfusion changes in an experimental model of acute pancreatitis: Evaluation by perfusion CT

    Energy Technology Data Exchange (ETDEWEB)

    Tutcu, Semra [Department of Surgery, Celal Bayar University, School of Medicine, Manisa (Turkey); Serter, Selim, E-mail: serterselim@gmail.co [Department of Radiology, Celal Bayar University, School of Medicine, Manisa (Turkey); Kaya, Yavuz; Kara, Eray [Department of Surgery, Celal Bayar University, School of Medicine, Manisa (Turkey); Nese, Nalan [Department of Pathology, Celal Bayar University, School of Medicine, Manisa (Turkey); Pekindil, Goekhan [Department of Radiology, Celal Bayar University, School of Medicine, Manisa (Turkey); Coskun, Teoman [Department of Surgery, Celal Bayar University, School of Medicine, Manisa (Turkey)

    2010-08-15

    Purpose: It is known that acute pancreatitis may cause secondary changes in several organs. Liver is one of these involved organs. In different experimental studies hepatic damages were shown histopathologically in acute pancreatitis but there are a few studies about perfusion disorders that accompany these histopathologic changes. Perfusion CT (pCT) provides the ability to detect regional and global alterations in organ blood flow. The purpose of the study was to describe hepatic perfusion changes in experimental acute pancreatitis model with pCT. Materials and methods: Forty Sprague-Dawley rats of both genders with average weights of 250 g were used. Rats were randomized into two groups. Twenty rats were in control group and 20 in acute pancreatitis group. pCT was performed. Perfusion maps were formed by processing the obtained images with perfusion CT software. Blood flow (BF) and blood volume (BV) values were obtained from these maps. All pancreatic and liver tissues were taken off with laparotomy and histopathologic investigation was performed. Student's t test was used for statistical analyses. Results: In pCT we found statistically significant increase in blood volume in both lobes of liver and in blood flow in right lobe of the liver (p < 0.01). Although blood flow in left lobe of the liver increased, it did not reach statistical significance. Conclusion: The quantitative analysis of liver parenchyma with pCT showed that acute pancreatitis causes a significant perfusion changes in the hepatic tissue. Systemic mediators seem to be effective as well as local inflammatory changes in perfusion changes.

  10. Diagnosis of Raynaud's phenomenon by (99m)Tc-pertechnetate hand perfusion scintigraphy: a pilot study.

    Science.gov (United States)

    Pavlov-Dolijanovic, Slavica; Petrovic, Nebojsa; Vujasinovic Stupar, Nada; Damjanov, Nemanja; Radunovic, Goran; Babic, Dragan; Sobic-Saranovic, Dragana; Artiko, Vera

    2016-12-01

    We assess the usefulness of (99m)Tc-pertechnetate hand perfusion scintigraphy in patients with Raynaud's phenomenon (RP). The study population consisted of 18 patients with primary RP, 25 patients with secondary RP within systemic sclerosis (SSc), and ten healthy individuals. Gamma camera dynamic first-pass study during the first 60 s and a static scintigraphy after 5 min were recorded following a bolus injection of (99m)Tc-pertechnetate via a cubital vein. Regions of interest were drawn on the summed images around the fingers and the palmar region. The fingers-to-palm ratios were then calculated. The mean fingers-to-palm ratio for dynamic study (blood flow) was 0.58 ± 0.19 for the healthy group, 0.45 ± 0.18 for the primary RP, and 0.43 ± 0.21 for the SSc patients. The mean fingers-to-palm ratio for static study (blood pool) was 0.44 ± 0.06 for the healthy group, 0.42 ± 0.06 for the primary RP, and 0.36 ± 0.07 for the SSc patients. Analysis of variance showed these differences to be significant (p = 0.039 from blood flow and p = 0.004 from blood pool). The receiver operating characteristic curve showed sensitivity of 80% and a specificity of 60% when using cutoff values of 0.40 for blood flow and sensitivity of 79% and a specificity of 70% when using cutoff values of 0.37 for blood pool. Our method is able to differentiate between patients with normal and those with abnormal microcirculation of the hands. Dynamic study separates the healthy subjects from patients with RP, while static study separates primary from secondary RP.

  11. Patient satisfaction with coronary CT angiography, myocardial CT perfusion, myocardial perfusion MRI, SPECT myocardial perfusion imaging and conventional coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Feger, S.; Rief, M.; Zimmermann, E.; Richter, F.; Roehle, R. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Dewey, M. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Institut fuer Radiologie, Berlin (Germany); Schoenenberger, E. [Medizinische Hochschule Hannover, Department of Medicine, Hannover (Germany)

    2015-07-15

    To evaluate patient acceptance of noninvasive imaging tests for detection of coronary artery disease (CAD), including single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI), stress perfusion magnetic resonance imaging (MRI), coronary CT angiography (CTA) in combination with CT myocardial stress perfusion (CTP), and conventional coronary angiography (CCA). Intraindividual comparison of perception of 48 patients from the CORE320 multicentre multinational study who underwent rest and stress SPECT-MPI with a technetium-based tracer, combined CTA and CTP (both with contrast agent, CTP with adenosine), MRI, and CCA. The analysis was performed by using a validated questionnaire. Patients had significantly more concern prior to CCA than before CTA/CTP (p < 0.001). CTA/CTP was also rated as more comfortable than SPECT-MPI (p = 0.001). Overall satisfaction with CT was superior to that of MRI (p = 0.007). More patients preferred CT (46 %; p < 0.001) as a future diagnostic test. Regarding combined CTA/CTP, CTP was characterised by higher pain levels and an increased frequency of angina pectoris during the examination (p < 0.001). Subgroup analysis showed a higher degree of pain during SPECT-MPI with adenosine stress compared to physical exercise (p = 0.016). All noninvasive cardiac imaging tests are well accepted by patients, with CT being the preferred examination. (orig.)

  12. A temporal interpolation approach for dynamic reconstruction in perfusion CT.

    Science.gov (United States)

    Montes, Pau; Lauritsch, Günter

    2007-07-01

    This article presents a dynamic CT reconstruction algorithm for objects with time dependent attenuation coefficient. Projection data acquired over several rotations are interpreted as samples of a continuous signal. Based on this idea, a temporal interpolation approach is proposed which provides the maximum temporal resolution for a given rotational speed of the CT scanner. Interpolation is performed using polynomial splines. The algorithm can be adapted to slow signals, reducing the amount of data acquired and the computational cost. A theoretical analysis of the approximations made by the algorithm is provided. In simulation studies, the temporal interpolation approach is compared with three other dynamic reconstruction algorithms based on linear regression, linear interpolation, and generalized Parker weighting. The presented algorithm exhibits the highest temporal resolution for a given sampling interval. Hence, our approach needs less input data to achieve a certain quality in the reconstruction than the other algorithms discussed or, equivalently, less x-ray exposure and computational complexity. The proposed algorithm additionally allows the possibility of using slow rotating scanners for perfusion imaging purposes.

  13. Optical coherence tomography microangiography for monitoring the response of vascular perfusion to external pressure on human skin tissue

    Science.gov (United States)

    Choi, Woo June; Wang, Hequn; Wang, Ruikang K.

    2014-05-01

    Characterization of the relationship between external pressure and blood flow is important in the examination of pressure-induced disturbance in tissue microcirculation. Optical coherence tomography (OCT)-based microangiography is a promising imaging technique, capable of providing the noninvasive extraction of functional vessels within the skin tissue with capillary-scale resolution. Here, we present a feasibility study of OCT microangiography (OMAG) to evaluate changes in blood perfusion in response to externally applied pressure on human skin tissue in vivo. External force is loaded normal to the tissue surface at the nailfold region of a healthy human volunteer. An incremental force is applied step by step and then followed by an immediate release. Skin perfusion events including baseline are continuously imaged by OMAG, allowing for visualization and quantification of the capillary perfusion in the nailfold tissue. The tissue strain maps are simultaneously evaluated through the available OCT structural images to assess the relationship of the microcirculation response to the applied pressure. The results indicate that the perfusion progressively decreases with the constant increase of pressure. Reactive hyperemia occurs right after the removal of the pressure. The perfusion returns to the baseline level after a few minutes. These findings suggest that OMAG may have great potential for quantitatively assessing tissue microcirculation in the locally pressed tissue in vivo.

  14. Safety and efficacy of distal perfusion catheterization to prevent limb ischemia after common femoral artery cannulation for extracorporeal membrane oxygenation

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Chang Ho; Seong, Nak Jong; Yoon, Chang Jin [Dept. of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of)

    2016-06-15

    The extracorporeal membrane oxygenation (ECMO) cannula has the potential for obstructing flow to the lower limb, thus causing severe ischemia and possible limb loss. We evaluated the safety and clinical efficacy of percutaneous distal perfusion catheterization in preventing limb ischemia. Between March 2013 and February 2015, 28 patients with distal perfusion catheterization after ECMO were included in this retrospective study. The technical success was evaluated by Doppler ultrasound at the popliteal level after saline injection via distal perfusion catheter. Clinical success was assessed when at least one of the following conditions was met: restoration of continuous peripheral limb oximetry value or presence of distal arterial pulse on Doppler ultrasound evaluation or resolution of early ischemic sign after connecting the catheter with ECMO. Twenty-six patients with early ischemia were successfully cannulated with a distal perfusion catheter (92.8%). Clinical success was achieved in 12/28 (42.8%) patients; 8/10 (80.0%) patients with survival duration exceeding 7 days and 4/18 (22.2%) patients with survival duration less than 7 days, respectively. A percutaneous distal perfusion catheter placement was a feasible tool with safety and efficacy in preventing lower limb ischemia for patients with prolonged common femoral arterial cannulation for ECMO.

  15. Diffusion and Perfusion Characteristics of MELAS (Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis, and Stroke-Like Episode) in Thirteen Patients

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Hye; Jeon, Tae Yeon; Eo, Hong; Yoo, So Young [Samsung Medical Center, Sungkyunkwan University, School of Medicine, Seoul (Korea, Republic of); Lim, Myung Kwan; Rha, Jung Ho; Shu, Chang Hae [Inha University Hospital, Incheon (Korea, Republic of)

    2011-02-15

    We analyzed the diffusion and perfusion characteristics of acute MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode) lesions in a large series to investigate the controversial changes of the apparent diffusion coefficient (ADC) that were reported in prior studies. We analyzed 44 newly appearing lesions during 28 stroke-like episodes in 13 patients with MELAS. We performed a visual assessment of the MR images including the ADC and perfusion maps, comparison of the ADC between the normal and abnormal areas, comparison of % ADC between the 44 MELAS lesions and the 30 acute ischemic infarcts. In addition, the patterns of evolution on follow-up MR images were analyzed. Decreased, increased, and normal ADCs were noted in 16 (36%), 16 (36%), and 12 (27%) lesions, respectively. The mean % ADC was 102 {+-} 40.9% in the MELAS and 64 {+-} 17.8% in the acute vascular infarcts (p < 0.001), while perfusion imaging demonstrated hyper-perfusion in six acute MELAS lesions. On follow-up images, resolution, progression, and tissue loss were noted in 10, 4, and 17 lesions, respectively. The cytotoxic edema gradually evolves following an acute stroke-like episode in patients with MELAS, and this may overlap with hyper-perfusion and vasogenic edema. The edematous swelling may be reversible or it may evolve to encephalomalacia, suggesting irreversible damage

  16. CT perfusion: ready for prime time.

    Science.gov (United States)

    Ambrose, Marietta S; Valdiviezo, Carolina; Mehra, Vishal; Lardo, Albert C; Lima, Joao A C; George, Richard T

    2011-02-01

    Advancements in computed tomography (CT) technology have revolutionized clinical practice, particularly regarding the noninvasive assessment of coronary artery disease (CAD). The versatility of cardiac CT has rendered multiple applications including assessment of cardiac structure and function, myocardial viability, and coronary anatomy. The merits of cardiac computed tomography angiography (CTA) have been proven for the detection, and particularly the exclusion, of CAD. However, CTA becomes limited in the presence of significant CAD. Its inability to consistently identify lesion-associated ischemia may necessitate additional radionuclide myocardial perfusion imaging. Myocardial computed tomography perfusion imaging (CTP) has emerged as a useful and convenient method to immediately assess myocardial ischemia. In this review, we discuss the current state of CTP including available technology, its performance to date from current literature, and future challenges to this field.

  17. Staging of moyamoya disease by perfusion SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Kuwabara, Yasuo [Kyushu Univ., Fukuoka (Japan). Hospital; Matsushima, Toshio; Fukui, Masashi

    2001-04-01

    Staging of moyamoya disease, based on angiography and PET have already been established. The authors have established staging of moyamoya disease based on perfusion SPECT, that can be summarized as follows: Stage I, no abnormality is seen at rest or after acetazolamide loading; Stage II, no abnormality is seen at rest, however, a decreased response (blood flow increase rate: <15%) is seen to acetazolamide loading (a, a decreased response is seen only in the frontal lobe; b, a decreased response is seen in regions other than the frontal lobe; and c, a decreased response is seen throughout the cerebrum); Stage III, localized decrease in blood flow (blood flow decrease compared with peripheral tissue: {>=}15%) and marked decrease in response to acetazolamide (blood flow increase rate: <5%) are seen at rest. In Stage III, CT and MRI show no abnormal findings or only mild lesions of the white matter; and Stage IV, multiple decreases in blood flow are seen at rest, and CT and MRI reveal infarctions and severe atrophy at the same sites. The above staging does not require determination of cerebral blood flow, and thus it can be used in children, in whom cerebral blood flow determination is difficult. The authors performed 99m-Tc ECD perfusion SPECT in 25 patients with moyamoya disease for the staging, and compared staging based on angiography with staging based on perfusion SPECT. The results did not show a correlation between the 2 staging methods. A problem inherent in the staging of moyamoya disease based on perfusion SPECT is that the relationship between cerebral blood flow and cerebral radioactivity concentrations may differ depending on the drug used to determine cerebral blood flow. Thus, although the present staging system does not depend on any specific radioactive drug to determine cerebral blood flow, further investigation is necessary to identify a more appropriate drug than those in current use. (K.H.)

  18. C-arm cone beam CT perfusion imaging in the angiographic suite: a comparison with MDCT perfusion imaging

    Science.gov (United States)

    Niu, Kai; Yang, Pengfei; Wu, Yijing; Struffert, Tobias; Doerfler, Arnd; Schafer, Sebastian; Royalty, Kevin; Strother, Charles; Chen, Guang-Hong

    2015-01-01

    Purpose and background Perfusion imaging in the angiography suite may provide a way to reduce time from stroke onset to endovascular revascularization of patients with a large vessel occlusion. Our purpose was to compare CBCTP with MDCTP. Materials and Methods Data from seven subjects with both MDCTP and CBCTP were retrospectively processed and analyzed. Two algorithms were used to enhance temporal resolution, temporal sampling density and reduce noise of CBCT data before generating perfusion maps. Two readers performed qualitative image quality evaluation on maps using a 5-point scale. ROIs indicating CBF/CBV abnormalities were drawn. Quantitative analyses were performed using the Sørensen–Dice coefficients to quantify the similarity of abnormalities. A non-inferiority hypothesis was tested to compare CBCTP against CBCTP. Results Averaged image quality score for MDCTP and CBCTP images was 2.4 and 2.3 respectively. Averaged confidence scores in diagnosis were both 1.4 for MDCT and CBCT; averaged confidence scores on presence of a CBV/CBF mismatch was 1.7 (κ = 0.50) and 1.5 (κ = 0.64). For MDCTP and CBCTP maps the average score of confidence in making treatment decision was 1.4 (κ = 0.79) and 1.3 (κ = 0.90). Area under visual grading characteristic (AVGC) for the above four qualitative quality score showed an average AVGC of 0.50 with 95% confidence level cover centered at the mean for both readers. Sørensen–Dice coefficient for CBF maps is 0.81 and for CBV maps is 0.55. Conclusions After post-processing methods were applied to enhance image quality for CBCTP maps, the CBCTP maps were not inferior to those generated from MDCTP. PMID:26892987

  19. Non-contrast MRI perfusion angiosome in diabetic feet

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jie [Cardiovascular Imaging Lab, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Hastings, Mary K.; Mueller, Michael J. [Washington University School of Medicine, The Program in Physical Therapy, St. Louis, MO (United States); Muccigross, David; Hildebolt, Charles F. [Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Fan, Zhaoyang [Cedars-Sinai Medical Center, Biomedical Imaging Research Institute, Los Angeles, CA (United States); Gao, Fabao [West China Hospital, Sichuan University, Department of Radiology, Chengdu (China); Curci, John [Washington University School of Medicine, The Department of Surgery, St. Louis, MO (United States)

    2015-01-15

    The purpose of this study is to develop a non-contrast magnetic resonance imaging (MRI) approach to evaluate skeletal muscle perfusion in the diabetic foot based on the concept of angiosomes of the foot. Five healthy volunteers and five participants with diabetes (HbA1c = 7.2 ± 1.8 %) without a history of peripheral artery disease were examined. The non-contrast perfusion measurements were performed during a toe flexion challenge. Absolute perfusion maps were created and two regions (medial and lateral) on the maps were segmented based on angiosomes. Regional difference in the perfusion of foot muscle was readily visualized in the MRI perfusion angiosomes during the challenge. In the participants with diabetes, the perfusion during toe flexion challenge was significantly lower than in healthy volunteers (P < 0.01). The average perfusion for the medial plantar region of the right foot was lower in subjects with diabetes (38 ± 9 ml/min/100 g) than in healthy subjects (93 ± 33 ml/min/100 g). Non-contrast MRI perfusion angiosome maps demonstrate the feasibility of determining regional perfusion in foot muscles during toe challenge and may facilitate evaluation of muscle perfusion in diabetic feet. (orig.)

  20. CT perfusion: principles, applications, and problems

    Science.gov (United States)

    Lee, Ting-Yim

    2004-10-01

    The fast scanning speed of current slip-ring CT scanners has enabled the development of perfusion imaging techniques with intravenous injection of contrast medium. In a typical CT perfusion study, contrast medium is injected and rapid scanning at a frequency of 1-2 Hz is used to monitor the first circulation of the injected contrast medium through a 1-2 cm thick slab of tissue. From the acquired time-series of CT images, arteries can be identified within the tissue slab to derive the arterial contrast concentration curve, Ca(t) while each individual voxel produces a tissue residue curve, Q(t) for the corresponding tissue region. Deconvolution between the measured Ca(t) and Q(t) leads to the determination of cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) in brain studies. In this presentation, an important application of CT perfusion in acute stroke studies - the identification of the ischemic penumbra via the CBF/CBV mismatch and factors affecting the quantitative accuracy of deconvolution, including partial volume averaging, arterial delay and dispersion are discussed.

  1. Myocardial perfusion imaging with dual energy CT.

    Science.gov (United States)

    Jin, Kwang Nam; De Cecco, Carlo N; Caruso, Damiano; Tesche, Christian; Spandorfer, Adam; Varga-Szemes, Akos; Schoepf, U Joseph

    2016-10-01

    Dual-energy CT (DECT) enables simultaneous use of two different tube voltages, thus different x-ray absorption characteristics are acquired in the same anatomic location with two different X-ray spectra. The various DECT techniques allow material decomposition and mapping of the iodine distribution within the myocardium. Static dual-energy myocardial perfusion imaging (sCTMPI) using pharmacological stress agents demonstrate myocardial ischemia by single snapshot images of myocardial iodine distribution. sCTMPI gives incremental values to coronary artery stenosis detected on coronary CT angiography (CCTA) by showing consequent reversible or fixed myocardial perfusion defects. The comprehensive acquisition of CCTA and sCTMPI offers extensive morphological and functional evaluation of coronary artery disease. Recent studies have revealed that dual-energy sCTMPI shows promising diagnostic accuracy for the detection of hemodynamically significant coronary artery disease compared to single-photon emission computed tomography, invasive coronary angiography, and cardiac MRI. The aim of this review is to present currently available DECT techniques for static myocardial perfusion imaging and recent clinical applications and ongoing investigations.

  2. Perfusion computed tomography in renal cell carcinoma

    Institute of Scientific and Technical Information of China (English)

    Chandan; J; Das; Usha; Thingujam; Ananya; Panda; Sanjay; Sharma; Arun; Kumar; Gupta

    2015-01-01

    Various imaging modalities are available for the diagnosis, staging and response evaluation of patients with renal cell carcinoma(RCC). While contrast enhanced computed tomography(CT) is used as the standard of imaging for size, morphological evaluation and response assessment in RCC, a new functional imaging technique like perfusion CT(p CT), goes down to the molecular level and provides new perspectives in imaging of RCC. p CT depicts regional tumor perfusion and vascular permeability which are indirect parameters of tumor angiogenesis and thereby provides vital information regarding tumor microenvironment. Also response evaluation using p CT may predate the size criteria used in Response Evaluation Criteria in Solid Tumors, as changes in the perfusion occurs earlier following tissue kinase inhibitors before any actual change in size. This may potentially help in predicting prognosis, better selection of therapy and more accurate and better response evaluation in patients with RCC. This article describes the techniques and role of p CT in staging and response assessment in patients with RCCs.

  3. Perfusion patterns in migraine with aura.

    Science.gov (United States)

    Förster, Alex; Wenz, Holger; Kerl, Hans U; Brockmann, Marc A; Groden, Christoph

    2014-10-01

    Migraine with aura is a common neurological disorder, and differentiation from transient ischemic attack or stroke based on clinical symptoms may be difficult. From an MRI report database we identified 33 patients with migraine with aura and compared these to 33 age-matched ischemic stroke patients regarding perfusion patterns on perfusion-weighted imaging (PWI)-derived maps: time to peak (TTP), mean transit time (MTT), and cerebral blood flow and volume (CBF, CBV). In 18/33 (54.5%) patients with migraine with aura, TTP showed areas of hypoperfusion, most of these not limited to the territory of a specific artery but affecting two or more vascular territories. In patients with migraine with aura, TTP (1.09 ± 0.05 vs. 1.47 ± 0.40, p aura is usually associated with a perfusion deficit not limited to a specific vascular territory, and only a moderate increase of TTP. Thus, hypoperfusion restricted to a single vascular territory in combination with a marked increase of TTP or MTT may be regarded as atypical for migraine aura and suggestive of acute ischemic stroke. © International Headache Society 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  4. Phosphorus NMR of isolated perfused morris hepatomas

    Energy Technology Data Exchange (ETDEWEB)

    Graham, R.A.; Meyer, R.A.; Brown, T.R.; Sauer, L.A.

    1986-03-05

    The authors are developing techniques for the study of perfused solid tumors by NMR. Tissue-isolated solid hepatomas were grown to 1-2 cm diameter as described previously. The arterial supply was isolated and the tumors perfused (0.5 - 1.0 ml/min) in vitro at 25 C with a 15% suspension of red blood cells in Krebs-Henseliet solution. /sup 31/P-NMR spectra were acquired at 162 MHz in a specially-designed NMR probe using a solenoidal coil. Intracellular pH (monitored from the chemical shift of inorganic phosphate) and ATP levels were stable for up to 6 hrs during perfusion. During 30 min of global ischemia, ATP decreased by 75% and pH fell from 7.0 to 6.7. These changes were reversed by 1 hr reperfusion. In addition to ATP and phosphate, the spectra included a large resonance due to phosphomonoesters, as well as peaks consistent with glycerylphosphocholine, glyceryl-phosphoethanolamine, phosphocreatine, NAD, and UDPG. However, the most novel feature of the spectra was the presence of an unidentified peak in the phosphonate region (+ 16.9 ppm). The peak was not present in spectra of muscle, liver, brain, kidney, or fat tissues excised from the same animals. They are presently attempting to identify the compound that gives rise to this peak and to establish its metabolic origin.

  5. Towards robust deconvolution of low-dose perfusion CT: sparse perfusion deconvolution using online dictionary learning.

    Science.gov (United States)

    Fang, Ruogu; Chen, Tsuhan; Sanelli, Pina C

    2013-05-01

    Computed tomography perfusion (CTP) is an important functional imaging modality in the evaluation of cerebrovascular diseases, particularly in acute stroke and vasospasm. However, the post-processed parametric maps of blood flow tend to be noisy, especially in low-dose CTP, due to the noisy contrast enhancement profile and the oscillatory nature of the results generated by the current computational methods. In this paper, we propose a robust sparse perfusion deconvolution method (SPD) to estimate cerebral blood flow in CTP performed at low radiation dose. We first build a dictionary from high-dose perfusion maps using online dictionary learning and then perform deconvolution-based hemodynamic parameters estimation on the low-dose CTP data. Our method is validated on clinical data of patients with normal and pathological CBF maps. The results show that we achieve superior performance than existing methods, and potentially improve the differentiation between normal and ischemic tissue in the brain.

  6. Brain perfusion: computed tomography and magnetic resonance techniques.

    Science.gov (United States)

    Copen, William A; Lev, Michael H; Rapalino, Otto

    2016-01-01

    Cerebral perfusion imaging provides assessment of regional microvascular hemodynamics in the living brain, enabling in vivo measurement of a variety of different hemodynamic parameters. Perfusion imaging techniques that are used in the clinical setting usually rely upon X-ray computed tomography (CT) or magnetic resonance imaging (MRI). This chapter reviews CT- and MRI-based perfusion imaging techniques, with attention to image acquisition, clinically relevant aspects of image postprocessing, and fundamental differences between CT- and MRI-based techniques. Correlations with cerebrovascular physiology and potential clinical applications of perfusion imaging are reviewed, focusing upon the two major classes of neurologic disease in which perfusion imaging is most often performed: primary perfusion disorders (including ischemic stroke, transient ischemic attack, and reperfusion syndrome), and brain tumors. © 2016 Elsevier B.V. All rights reserved.

  7. Whole-brain dynamic CT angiography and perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Orrison, W.W. [CHW Nevada Imaging Company, Nevada Imaging Centers, Spring Valley, Las Vegas, NV (United States); College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Department of Medical Education, University of Nevada School of Medicine, Reno, NV (United States); Snyder, K.V.; Hopkins, L.N. [Department of Neurosurgery, Millard Fillmore Gates Circle Hospital, Buffalo, NY (United States); Roach, C.J. [School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States); Ringdahl, E.N. [Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV (United States); Nazir, R. [Shifa International Hospital, Islamabad (Pakistan); Hanson, E.H., E-mail: eric.hanson@amigenics.co [College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States)

    2011-06-15

    The availability of whole brain computed tomography (CT) perfusion has expanded the opportunities for analysing the haemodynamic parameters associated with varied neurological conditions. Examples demonstrating the clinical utility of whole-brain CT perfusion imaging in selected acute and chronic ischaemic arterial neurovascular conditions are presented. Whole-brain CT perfusion enables the detection and focused haemodynamic analyses of acute and chronic arterial conditions in the central nervous system without the limitation of partial anatomical coverage of the brain.

  8. Scintigraphic control of blood vessels in regional perfusion with cytostatics

    Energy Technology Data Exchange (ETDEWEB)

    Blazek, J.; Broz, J. (Krajska Nemocnice s Poliklinikou, Ceske Budejovice (Czechoslovakia))

    1982-12-01

    After administration of sup(99m)Tc-MAA or sup(113m)In-MAA into the perfusion system during regional perfusion therapy with cytostatics of malignomas in the maxillo-facial area it is possible to obtain by subsequent scintigraphic visualization of the distribution of radioactivity an accurate topographic picture of the perfusion in the appropriate area. The method is free from complications and there are no contraindications. The paper is supplemented by scintigrams.

  9. Metabolic response of perfused livers to various oxygenation conditions.

    Science.gov (United States)

    Orman, Mehmet A; Ierapetritou, Marianthi G; Androulakis, Ioannis P; Berthiaume, Francois

    2011-12-01

    Isolated liver perfusion systems have been used to characterize intrinsic metabolic changes in liver as a result of various perturbations, including systemic injury, hepatotoxin exposure, and warm ischemia. Most of these studies were done using hyperoxic conditions (95% O(2)) but without the use of oxygen carriers in the perfusate. Prior literature data do not clearly establish the impact of oxygenation, and in particular that of adding oxygen carriers to the perfusate, on the metabolic functions of the liver. Therefore, herein the effects of oxygen delivery in the perfusion system on liver metabolism were investigated by comparing three modes of oxygenation. Rat livers were perfused via the portal and hepatic veins at a constant flow rate of 3 mL/min/g liver in a recirculating perfusion system. In the first group, the perfusate was equilibrated in a membrane oxygenator with room air (21% O(2)) before entering the liver. In the second group, the perfusate was equilibrated with a 95% O(2)/5% CO(2) gas mixture. In the third group, the perfusate was supplemented with washed bovine red blood cells (RBCs) at 10% hematocrit and also equilibrated with the 95% O(2)/5% CO(2) gas mixture. Oxygen and CO(2) gradients across the liver were measured periodically with a blood gas analyzer. The rate of change in the concentration of major metabolites in the perfusate was measured over time. Net extracellular fluxes were calculated from these measurements and applied to a stoichiometric-based optimization problem to determine the intracellular fluxes and active pathways in the perfused livers. Livers perfused with RBCs consumed oxygen at twice the rate observed using hyperoxic (95% O(2)) perfusate without RBCs, and also produced more urea and ketone bodies. At the flow rate used, the oxygen supply in perfusate without RBCs was just sufficient to meet the average oxygen demand of the liver but would be insufficient if it increased above baseline, as is often the case in response to

  10. Lung perfusion CT: The differentiation of cavitary mass

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Han [Department of Radiology, Yonsei University Wonju College of Medicine, 162 Ilsan-dong, Wonju (Korea, Republic of); Kwon, Woocheol [Department of Radiology, Yonsei University Wonju College of Medicine, 162 Ilsan-dong, Wonju (Korea, Republic of)], E-mail: wckwon@yonsei.ac.kr; Kim, Myung Soon; Kim, Young Ju; Lee, Myeong Sub [Department of Radiology, Yonsei University Wonju College of Medicine, 162 Ilsan-dong, Wonju (Korea, Republic of); Yong, Suk Joong [Division of Pulmonology, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju (Korea, Republic of); Jung, Soon-Hee [Department of Pathology, Yonsei University Wonju College of Medicine, Wonju (Korea, Republic of); Chang, Sei-Jin [Department of Preventive Medicine, Yonsei University Wonju College of Medicine, Wonju (Korea, Republic of); Sung, Ki Joon [Department of Radiology, Yonsei University Wonju College of Medicine, 162 Ilsan-dong, Wonju (Korea, Republic of)

    2010-01-15

    Purpose: To assess the findings of perfusion maps and to evaluate the usefulness of perfusion computed tomography (CT) in the differentiation of cavitary mass. Materials and methods: Fifty-three patients with cavitary lung masses were analyzed. Dynamic chest CT was performed after contrast injection. The volume map, washout map, peak map, and time-to-peak (TTP) map were reformatted using Interactive Data Language (IDL). The perfusion patterns were classified into three scoring groups, and these scorings were repeated after 2-week intervals. Diagnostic confidence levels were assigned by consensus. The kappa statistics was used to determine intraobserver agreement, and Fisher's exact test was used to analyze statistical differences in perfusion scores. Receiver operating characteristic (ROC) analysis was performed to evaluate the usefulness of the perfusion maps. Results: Perfusion maps were reformatted pixel-by-pixel from the time-to-density curve analyses. Pyogenic cavities showed weak washout and slow TTP (69.6%). Conversely, malignant cavities showed strong washout (73.3%). Tuberculous cavities showed low perfusions in the volume and peak maps (66.7%). Intraobserver agreement was excellent. The performance of the combination of CT and perfusion maps was better than that of CT alone. Conclusion: Lung perfusion CT could be a promising and feasible method for differentiation of cavitary mass.

  11. CT perfusion of the liver: principles and applications in oncology.

    Science.gov (United States)

    Kim, Se Hyung; Kamaya, Aya; Willmann, Jürgen K

    2014-08-01

    With the introduction of molecularly targeted chemotherapeutics, there is an increasing need for defining new response criteria for therapeutic success because use of morphologic imaging alone may not fully assess tumor response. Computed tomographic (CT) perfusion imaging of the liver provides functional information about the microcirculation of normal parenchyma and focal liver lesions and is a promising technique for assessing the efficacy of various anticancer treatments. CT perfusion also shows promising results for diagnosing primary or metastatic tumors, for predicting early response to anticancer treatments, and for monitoring tumor recurrence after therapy. Many of the limitations of early CT perfusion studies performed in the liver, such as limited coverage, motion artifacts, and high radiation dose of CT, are being addressed by recent technical advances. These include a wide area detector with or without volumetric spiral or shuttle modes, motion correction algorithms, and new CT reconstruction technologies such as iterative algorithms. Although several issues related to perfusion imaging-such as paucity of large multicenter trials, limited accessibility of perfusion software, and lack of standardization in methods-remain unsolved, CT perfusion has now reached technical maturity, allowing for its use in assessing tumor vascularity in larger-scale prospective clinical trials. In this review, basic principles, current acquisition protocols, and pharmacokinetic models used for CT perfusion imaging of the liver are described. Various oncologic applications of CT perfusion of the liver are discussed and current challenges, as well as possible solutions, for CT perfusion are presented.

  12. Effect of Defocused CO2 Laser on Equine Tissue Perfusion

    Directory of Open Access Journals (Sweden)

    Bergh A

    2006-03-01

    Full Text Available Treatment with defocused CO2 laser can have a therapeutic effect on equine injuries, but the mechanisms involved are unclear. A recent study has shown that laser causes an increase in equine superficial tissue temperature, which may result in an increase in blood perfusion and a stimulating effect on tissue regeneration. However, no studies have described the effects on equine tissue perfusion. The aim of the present study was to investigate the effect of defocused CO2 laser on blood perfusion and to correlate it with temperature in skin and underlying muscle in anaesthetized horses. Differences between clipped and unclipped haircoat were also assessed. Eight horses and two controls received CO2 laser treatment (91 J/cm2 in a randomised order, on a clipped and unclipped area of the hamstring muscles, respectively. The significant increase in clipped skin perfusion and temperature was on average 146.3 ± 33.4 perfusion units (334% and 5.5 ± 1.5°C, respectively. The significant increase in perfusion and temperature in unclipped skin were 80.6 ± 20.4 perfusion units (264% and 4.8 ± 1.4°C. No significant changes were seen in muscle perfusion or temperature. In conclusion, treatment with defocused CO2 laser causes a significant increase in skin perfusion, which is correlated to an increase in skin temperature.

  13. Ex Situ Normothermic Machine Perfusion of Donor Livers

    Science.gov (United States)

    Karimian, Negin; Matton, Alix P.M.; Westerkamp, Andrie C.; Burlage, Laura C.; op den Dries, Sanna; Leuvenink, Henri G.D.; Lisman, Ton; Uygun, Korkut; Markmann, James F.; Porte, Robert J.

    2015-01-01

    In contrast to conventional static cold preservation (0-4 °C), ex situ machine perfusion may provide better preservation of donor livers. Continuous perfusion of organs provides the opportunity to improve organ quality and allows ex situ viability assessment of donor livers prior to transplantation. This video article provides a step by step protocol for ex situ normothermic machine perfusion (37 °C) of human donor livers using a device that provides a pressure and temperature controlled pulsatile perfusion of the hepatic artery and continuous perfusion of the portal vein. The perfusion fluid is oxygenated by two hollow fiber membrane oxygenators and the temperature can be regulated between 10 °C and 37 °C. During perfusion, the metabolic activity of the liver as well as the degree of injury can be assessed by biochemical analysis of samples taken from the perfusion fluid. Machine perfusion is a very promising tool to increase the number of livers that are suitable for transplantation. PMID:26067131

  14. Myocardial Perfusion Spect Imaging in Dextrocardia: A Case Report

    Directory of Open Access Journals (Sweden)

    Semra Özdemir

    2013-08-01

    Full Text Available The myocardial perfusion scintigraphy acquisition and analysis present some technical differences in the rare dextrocardia cases. Here we report a case of a 38 year-old woman with dextrocardia who had been applied myocardial perfusion scintigraphy. Presented case showed that the thoracic and abdominal organs had a mirror image with situs inversus totalis type dextrocardia. The incidence of coronary heart disease and life span of people with situs inversus totalis are the same as the normal population. So we may apply myocardial perfusion scintigraphy to this patient group. The current case is presented in order to remind the special applications of myocardial perfusion SPECT imaging in patients with dextrocardia.

  15. Radionuclide Tracers for Myocardial Perfusion Imaging and Blood Flow Quantification.

    Science.gov (United States)

    deKemp, Robert A; Renaud, Jennifer M; Klein, Ran; Beanlands, Rob S B

    2016-02-01

    Myocardial perfusion imaging is performed most commonly using Tc-99m-sestamibi or tetrofosmin SPECT as well as Rb-82-rubidium or N-13-ammonia PET. Diseased-to-normal tissue contrast is determined by the tracer retention fraction, which decreases nonlinearly with flow. Reduced tissue perfusion results in reduced tracer retention, but the severity of perfusion defects is typically underestimated by 20% to 40%. Compared to SPECT, retention of the PET tracers is more linearly related to flow, and therefore, the perfusion defects are measured more accurately using N-13-ammonia or Rb-82.

  16. Can preoperative myocardial perfusion scintigraphy predict changes in left ventricular perfusion and function after coronary artery bypass graft surgery?

    DEFF Research Database (Denmark)

    Eckardt, Rozy; Kjeldsen, Bo Juel; Johansen, Allan;

    2012-01-01

    OBJECTIVESWe wanted to evaluate whether preoperative myocardial perfusion scintigraphy (MPS) could predict changes in cardiac symptoms and postoperative myocardial perfusion and left ventricular function after coronary artery bypass grafting (CABG).METHODSNinety-two patients with stable angina......%. Before CABG, one patient had normal perfusion; in the rest of them the defects were classified as follows: reversible (60%), partly reversible (27%) and irreversible (12%). Following CABG, 33% had normal perfusion; in the rest the defects were reversible in 29%, partly reversible in 12% and irreversible...... in 26%. Left ventricular ejection fraction (LVEF), which was normal before operation in 45%, improved in 40% of all patients. The increase in LVEF was not related to the preoperative pattern of perfusion defects. Of 30 patients with normalized perfusion after CABG, 29 (97%) had reversible defects...

  17. Perfusion vector - a new method to quantify myocardial perfusion scintigraphy images: a simulation study with validation in patients

    DEFF Research Database (Denmark)

    Minarik, David; Senneby, Martin; Wollmer, Per

    2015-01-01

    Background The interpretation of myocardial perfusion scintigraphy (MPS) largely relies on visual assessment by the physician of the localization and extent of a perfusion defect. The aim of this study was to introduce the concept of the perfusion vector as a new objective quantitative method...... for further assisting the visual interpretation and to test the concept using simulated MPS images as well as patients. Methods The perfusion vector is based on calculating the difference between the anatomical centroid and the perfusion center of gravity of the left ventricle. Simulated MPS images were.......001) but not for patients with infarction. The correlation between the defect size and stress vector magnitude was also found to be significant (p concept of the perfusion vector introduced in this study is shown to have potential in assisting the visual interpretation in MPS studies. Further...

  18. Phthalate monoesters in perfusate from a dual placenta perfusion system, the placenta tissue and umbilical cord blood

    DEFF Research Database (Denmark)

    Mose, Tina; Mortensen, Gerda K; Hedegaard, Morten;

    2006-01-01

    Fetal exposure to phthalates may be associated with adverse reproductive effects, including cryptorchidism and decreased semen quality. Information about human placental transfer is needed to qualify the hypotheses. A dual recirculating placenta perfusion system to monitor concentrations of eight...... phthalate monoesters in fetal and maternal perfusates was established. In addition to perfusate background measures of phthalate monoesters, the concentrations in umbilical cord plasma and placenta tissue were measured. Monomethyl phthalate (mMP), monoethyl phthalate (mEP), monobutyl phthalate (m...

  19. Evaluation of cerebral hemodynamics with perfusion CT

    Energy Technology Data Exchange (ETDEWEB)

    Araki, Yuzo; Furuichi, Masahiro; Nokura, Hiroaki [Inuyama Central Hospital, Aichi (Japan); Sakai, Noboru [Gifu Univ. (Japan). School of Medicine

    2002-07-01

    We report on the evaluation of cerebral ischemic lesions with perfusion CT. Cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) of 52 patients mostly with ischemic cerebrovascular disease were analysed using the box-modulation transfer function method with 30 ml of contrast medium intravenously injected at 5 ml/sec. CBF, CBV and MTT of the middle cerebral artery (MCA) territory were 43.5{+-}4.6 ml/100 g/min, 1.9{+-}0.2 ml/100 g and 2.9{+-}0.6 seconds at the unaffected side, and 37.7{+-}7.3 ml/100 g /min, 2.1{+-}0.3 ml/100 g, 3.7{+-}0.9 seconds at the lesion side with stenosis or occlusion in the main MCA trunks or internal carotid artery, respectively. A statistically significant difference was shown in CBF and MTT values. Furthermore, there was a close correlation in CBF values of MCA territories between Xe-CT and perfusion CT (r=0.645, n=76, p<0.0001). MTT showed a positive correlation with CBV in those subjects when MTT was below 4.1 seconds (r=0.526, p<0.0001, n=83). MTT also showed a negative correlation with CBF in those patients when MTT indicated more than 4.1 seconds (r=0.818, p<0.001, n=21). These results suggest that the progression of cerebral ischemia may be classified in 4 stages using perfusion CT. The stages are as follows: stage 0; normal CBF without prolonged MTT and increased CBV, stage 1; relatively increased CBV, stage 2; significantly prolonged MTT, and stage 3; significantly deceased CBF with prolonged MTT. (author)

  20. Pseudoketogenesis in the perfused rat heart

    Energy Technology Data Exchange (ETDEWEB)

    Fink, G.; Desrochers, S.; Des Rosiers, C.; Garneau, M.; David, F.; Daloze, T.; Landau, B.R.; Brunengraber, H.

    1988-12-05

    Ketogenesis is usually measured in vivo by dilution of tracers of (3R)-hydroxybutyrate or acetoacetate. We show that, in perfused working rat hearts, the specific activities of (3R)-hydroxybutyrate and acetoacetate are diluted by isotopic exchanges in the absence of net ketogenesis. We call this process pseudoketogenesis. When hearts are perfused with buffer containing 2.3 mM of (4-3H)- plus (3-14C)acetoacetate, the specific activities of (4-3H) and (3-14C)acetoacetate decrease while C-1 of acetoacetate becomes progressively labeled with 14C. This is explained by the reversibility of reactions catalyzed by mitochondrial 3-oxoacid-CoA transferase and acetoacetyl-CoA thiolase. After activation of labeled acetoacetate, the specific activity of acetoacetyl-CoA is diluted by unlabeled acetoacetyl-CoA derived from endogenous fatty acids or glucose. Acetoacetyl-CoA thiolase partially exchanges 14C between C-1 and C-3 of acetoacetyl-CoA. Finally, 3-oxoacid-CoA transferase liberates weakly labeled acetoacetate which dilutes the specific activity of extracellular acetoacetate. An isotopic exchange in the reverse direction is observed when hearts are perfused with unlabeled acetoacetate plus (1-14C)-, (13-14C)-, or (15-14C)palmitate; here also, acetoacetate becomes labeled on C-1 and C-3. Computations of specific activities of (3R)-hydroxybutyrate, acetoacetate, and acetyl-CoA yield minimal rates of pseudoketogenesis ranging from 19 to 32% of the net uptake of (3R)-hydroxybutyrate plus acetoacetate by the heart.

  1. Metabolomic perfusate analysis during kidney machine perfusion: the pig provides an appropriate model for human studies.

    Directory of Open Access Journals (Sweden)

    Jay Nath

    Full Text Available Hypothermic machine perfusion offers great promise in kidney transplantation and experimental studies are needed to establish the optimal conditions for this to occur. Pig kidneys are considered to be a good model for this purpose and share many properties with human organs. However it is not established whether the metabolism of pig kidneys in such hypothermic hypoxic conditions is comparable to human organs.Standard criteria human (n = 12 and porcine (n = 10 kidneys underwent HMP using the LifePort Kidney Transporter 1.0 (Organ Recovery Systems using KPS-1 solution. Perfusate was sampled at 45 minutes and 4 hours of perfusion and metabolomic analysis performed using 1-D 1H-NMR spectroscopy.There was no inter-species difference in the number of metabolites identified. Of the 30 metabolites analysed, 16 (53.3% were present in comparable concentrations in the pig and human kidney perfusates. The rate of change of concentration for 3-Hydroxybutyrate was greater for human kidneys (p<0.001. For the other 29 metabolites (96.7%, there was no difference in the rate of change of concentration between pig and human samples.Whilst there are some differences between pig and human kidneys during HMP they appear to be metabolically similar and the pig seems to be a valid model for human studies.

  2. Xeno- and auto-perfusion of rabbit kidney. Machine perfusion with blood at 37 degrees C

    DEFF Research Database (Denmark)

    Jørgensen, K A; Kemp, E; Barfort, P;

    1985-01-01

    Five rabbit kidneys were perfused with human blood and another five with their own blood in a re-circulating oxygenated system at 37 degrees C. The flow decreased to 2 ml/min. within 30 min. in all xenoperfusions, while none of the autoperfused had decreased to this level by 60 min. Endothelial...

  3. Demonstration of cerebral perfusion abnormalities in moyamoya disease using susceptibility perfusion- and diffusion-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Adams, W.M.; Laitt, R.D. [Department of Neuroradiology, Central Manchester Healthcare Trust, Oxford Road, Manchester M13 9WL (United Kingdom); Li, K.L.; Jackson, A. [Department of Diagnostic Radiology, University of Manchester, Manchester M13 9PT (United Kingdom); Sherrington, C.R.; Talbot, P. [Department of Neurology, Central Manchester Healthcare Trust, Oxford Road, Manchester M13 9WL (United Kingdom)

    1999-02-01

    We describe the use of diffusion-weighted imaging and perfusion MRI using a contrast-medium bolus in the preoperative investigation for young man presenting with a cerebral ischaemic episode as a manifestation of moyamoya disease. (orig.) With 6 figs., 21 refs.

  4. Multi-delay arterial spin labeling perfusion MRI in moyamoya disease-comparison with CT perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rui [Chinese Academy of Sciences, State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Beijing (China); University of Chinese Academy of Sciences, Graduate School, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Los Angeles, CA (United States); Yu, Songlin [Capital Medical University, Department of Neurosurgery, Beijing Tiantan Hospital, Beijing (China); University of California Los Angeles, Department of Neurology, Los Angeles (United States); Alger, Jeffry R.; Wang, Danny J.J. [University of California Los Angeles, Department of Neurology, Los Angeles (United States); UCLA-Beijing Joint Center for Advanced Brain Imaging, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Los Angeles, CA (United States); Zuo, Zhentao; Wang, Bo [Chinese Academy of Sciences, State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Beijing (China); Chen, Juan [Beijing Hospital, Department of Radiology, Beijing (China); Wang, Rong; Zhao, Jizong [Capital Medical University, Department of Neurosurgery, Beijing Tiantan Hospital, Beijing (China); An, Jing [Siemens Shenzhen Magnetic Resonance Ltd, Shenzhen (China); Xue, Rong [Chinese Academy of Sciences, State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Los Angeles, CA (United States)

    2014-05-15

    To present a multi-delay pseudo-continuous ASL (pCASL) protocol that offers simultaneous measurements of cerebral blood flow (CBF) and arterial transit time (ATT), and to study correlations between multi-delay pCASL and CT perfusion in moyamoya disease. A 4 post-labeling delay (PLD) pCASL protocol was applied on 17 patients with moyamoya disease who also underwent CT perfusion imaging. ATT was estimated using the multi-delay protocol and included in the calculation of CBF. ASL and CT perfusion images were rated for lesion severity/conspicuity. Pearson correlation coefficients were calculated across voxels between the two modalities in grey and white matter of each subject respectively and between normalized mean values of ASL and CT perfusion measures in major vascular territories. Significant associations between ASL and CT perfusion were detected using subjective ratings, voxel-wise analysis in grey and white matter and region of interest (ROI)-based analysis of normalized mean perfusion. The correlation between ASL CBF and CT perfusion was improved using the multi-delay pCASL protocol compared to CBF acquired at a single PLD of 2 s (P < 0.05). There is a correlation between perfusion data from ASL and CT perfusion imaging in patients with moyamoya disease. Multi-delay ASL can improve CBF quantification, which could be a prognostic imaging biomarker in patients with moyamoya disease. (orig.)

  5. Portable laser speckle perfusion imaging system based on digital signal processor.

    Science.gov (United States)

    Tang, Xuejun; Feng, Nengyun; Sun, Xiaoli; Li, Pengcheng; Luo, Qingming

    2010-12-01

    The ability to monitor blood flow in vivo is of major importance in clinical diagnosis and in basic researches of life science. As a noninvasive full-field technique without the need of scanning, laser speckle contrast imaging (LSCI) is widely used to study blood flow with high spatial and temporal resolution. Current LSCI systems are based on personal computers for image processing with large size, which potentially limit the widespread clinical utility. The need for portable laser speckle contrast imaging system that does not compromise processing efficiency is crucial in clinical diagnosis. However, the processing of laser speckle contrast images is time-consuming due to the heavy calculation for enormous high-resolution image data. To address this problem, a portable laser speckle perfusion imaging system based on digital signal processor (DSP) and the algorithm which is suitable for DSP is described. With highly integrated DSP and the algorithm, we have markedly reduced the size and weight of the system as well as its energy consumption while preserving the high processing speed. In vivo experiments demonstrate that our portable laser speckle perfusion imaging system can obtain blood flow images at 25 frames per second with the resolution of 640 × 480 pixels. The portable and lightweight features make it capable of being adapted to a wide variety of application areas such as research laboratory, operating room, ambulance, and even disaster site.

  6. Four dimensional optoacoustic imaging of perfusion in preclinical breast tumor model in vivo (Conference Presentation)

    Science.gov (United States)

    Deán-Ben, Xosé Luís.; Ermolayev, Vladimir; Mandal, Subhamoy; Ntziachristos, Vasilis; Razansky, Daniel

    2016-03-01

    Imaging plays an increasingly important role in clinical management and preclinical studies of cancer. Application of optical molecular imaging technologies, in combination with highly specific contrast agent approaches, eminently contributed to understanding of functional and histological properties of tumors and anticancer therapies. Yet, optical imaging exhibits deterioration in spatial resolution and other performance metrics due to light scattering in deep living tissues. High resolution molecular imaging at the whole-organ or whole-body scale may therefore bring additional understanding of vascular networks, blood perfusion and microenvironment gradients of malignancies. In this work, we constructed a volumetric multispectral optoacoustic tomography (vMSOT) scanner for cancer imaging in preclinical models and explored its capacity for real-time 3D intravital imaging of whole breast cancer allografts in mice. Intrinsic tissue properties, such as blood oxygenation gradients, along with the distribution of externally administered liposomes carrying clinically-approved indocyanine green dye (lipo-ICG) were visualized in order to study vascularization, probe penetration and extravasation kinetics in different regions of interest within solid tumors. The use of v-MSOT along with the application of volumetric image analysis and perfusion tracking tools for studies of pathophysiological processes within microenvironment gradients of solid tumors demonstrated superior volumetric imaging system performance with sustained competitive resolution and imaging depth suitable for investigations in preclinical cancer models.

  7. Dynamic perfusion CT in brain tumors.

    Science.gov (United States)

    Yeung, Timothy Pok Chi; Bauman, Glenn; Yartsev, Slav; Fainardi, Enrico; Macdonald, David; Lee, Ting-Yim

    2015-12-01

    Dynamic perfusion CT (PCT) is an imaging technique for assessing the vascular supply and hemodynamics of brain tumors by measuring blood flow, blood volume, and permeability-surface area product. These PCT parameters provide information complementary to histopathologic assessments and have been used for grading brain tumors, distinguishing high-grade gliomas from other brain lesions, differentiating true progression from post-treatment effects, and predicting prognosis after treatments. In this review, the basic principles of PCT are described, and applications of PCT of brain tumors are discussed. The advantages and current challenges, along with possible solutions, of PCT are presented.

  8. Three-dimensional MRI perfusion maps: a step beyond volumetric analysis in mental disorders.

    Science.gov (United States)

    Fabene, Paolo F; Farace, Paolo; Brambilla, Paolo; Andreone, Nicola; Cerini, Roberto; Pelizza, Luisa; Versace, Amelia; Rambaldelli, Gianluca; Birbaumer, Niels; Tansella, Michele; Sbarbati, Andrea

    2007-01-01

    A new type of magnetic resonance imaging analysis, based on fusion of three-dimensional reconstructions of time-to-peak parametric maps and high-resolution T1-weighted images, is proposed in order to evaluate the perfusion of selected volumes of interest. Because in recent years a wealth of data have suggested the crucial involvement of vascular alterations in mental diseases, we tested our new method on a restricted sample of schizophrenic patients and matched healthy controls. The perfusion of the whole brain was compared with that of the caudate nucleus by means of intrasubject analysis. As expected, owing to the encephalic vascular pattern, a significantly lower time-to-peak was observed in the caudate nucleus than in the whole brain in all healthy controls, indicating that the suggested method has enough sensitivity to detect subtle perfusion changes even in small volumes of interest. Interestingly, a less uniform pattern was observed in the schizophrenic patients. The latter finding needs to be replicated in an adequate number of subjects. In summary, the three-dimensional analysis method we propose has been shown to be a feasible tool for revealing subtle vascular changes both in normal subjects and in pathological conditions.

  9. Effect of vasospasm on perfusion radionuclide imaging in experimental pulmonary embolism

    Energy Technology Data Exchange (ETDEWEB)

    Feigin, D.S.; Bookstein, J.J.; Alazraki, N.P.

    Experiments were conducted to further evaluate previously observed discrepancies between postembolic perfusion scans and angiograms, and the relationship of these discrepancies to pulmonary vasospasm. Nonresorbable emboli were formed from Ivalon, muscle, or heated autologous clot. Scans and angiograms were compared at 24-hour intervals for two to eight days. During the first two days after embolism, angiographic-scan discrepancies occurred in most dogs, characterized by decreased size of scintigraphically demonstrated perfusion defects at the same times that the angiogram showed stable or even progressive obstruction. This discordant behavior of scan and angiogram is thought to reflect subsidence of postembolic vasospasm. In the 17 experimental dogs, 13 showed evidence of vasospasm, and four did not. In those that developed spasm, direct angiographic evidence of such spasm was present in all but one, manifest as diffuse constriction of small arteries and diminished parenchymal stain in vascular beds that were not directly obstructed mechanically. Although spasm diminished rapidly during the first 6 hours, there was continued and appreciable further resolution for over 48 hours in some dogs. This study reconfirms the frequent existence of vasospasm in three different embolic models, and indicates subsidence of spasm over a much longer time frame than was formerly supposed. Regression of spasm over an interval of several days suggests that perfusion scans should be performed clinically as soon as possible after a suspected embolic episode, prior to subsidence of spasm, in order to exploit the added sensitivity provided by spasm.

  10. Dynamic CT myocardial perfusion imaging: detection of ischemia in a porcine model with FFR verification

    Science.gov (United States)

    Fahmi, Rachid; Eck, Brendan L.; Vembar, Mani; Bezerra, Hiram G.; Wilson, David L.

    2014-03-01

    Dynamic cardiac CT perfusion (CTP) is a high resolution, non-invasive technique for assessing myocardial blood ow (MBF), which in concert with coronary CT angiography enable CT to provide a unique, comprehensive, fast analysis of both coronary anatomy and functional ow. We assessed perfusion in a porcine model with and without coronary occlusion. To induce occlusion, each animal underwent left anterior descending (LAD) stent implantation and angioplasty balloon insertion. Normal ow condition was obtained with balloon completely de ated. Partial occlusion was induced by balloon in ation against the stent with FFR used to assess the extent of occlusion. Prospective ECG-triggered partial scan images were acquired at end systole (45% R-R) using a multi-detector CT (MDCT) scanner. Images were reconstructed using FBP and a hybrid iterative reconstruction (iDose4, Philips Healthcare). Processing included: beam hardening (BH) correction, registration of image volumes using 3D cubic B-spline normalized mutual-information, and spatio-temporal bilateral ltering to reduce partial scan artifacts and noise variation. Absolute blood ow was calculated with a deconvolutionbased approach using singular value decomposition (SVD). Arterial input function was estimated from the left ventricle (LV) cavity. Regions of interest (ROIs) were identi ed in healthy and ischemic myocardium and compared in normal and occluded conditions. Under-perfusion was detected in the correct LAD territory and ow reduction agreed well with FFR measurements. Flow was reduced, on average, in LAD territories by 54%.

  11. Perfusion deficits and functional connectivity alterations in patients with post-traumatic stress disorder

    Science.gov (United States)

    Liu, Yang; Li, Baojuan; Zhang, Xi; Zhang, Linchuan; Li, Liang; Lu, Hongbing

    2016-03-01

    To explore the alteration in cerebral blood flow (CBF) and functional connectivity between survivors with recent onset post-traumatic stress disorder (PTSD) and without PTSD, survived from the same coal mine flood disaster. In this study, a processing pipeline using arterial spin labeling (ASL) sequence was proposed. Considering low spatial resolution of ASL sequence, a linear regression method was firstly used to correct the partial volume (PV) effect for better CBF estimation. Then the alterations of CBF between two groups were analyzed using both uncorrected and PV-corrected CBF maps. Based on altered CBF regions detected from the CBF analysis as seed regions, the functional connectivity abnormities in PTSD patients was investigated. The CBF analysis using PV-corrected maps indicates CBF deficits in the bilateral frontal lobe, right superior frontal gyrus and right corpus callosum of PTSD patients, while only right corpus callosum was identified in uncorrected CBF analysis. Furthermore, the regional CBF of the right superior frontal gyrus exhibits significantly negative correlation with the symptom severity in PTSD patients. The resting-state functional connectivity indicates increased connectivity between left frontal lobe and right parietal lobe. These results indicate that PV-corrected CBF exhibits more subtle perfusion changes and may benefit further perfusion and connectivity analysis. The symptom-specific perfusion deficits and aberrant connectivity in above memory-related regions may be putative biomarkers for recent onset PTSD induced by a single prolonged trauma exposure and help predict the severity of PTSD.

  12. Perfusion heterogeneity in human skeletal muscle: fractal analysis of PET data

    Energy Technology Data Exchange (ETDEWEB)

    Kalliokoski, K.K.; Tolvanen, T.; Oikonen, V.; Teraes, M.; Knuuti, J. [Turku PET Centre, University of Turku (Finland); Kuusela, T.A. [Department of Applied Physics, University of Turku, Turku (Finland); Nuutila, P. [Turku PET Centre, University of Turku (Finland); Dept. of Medicine, University of Turku, Turku (Finland); Takala, T.E.S. [Department of Biology of Physical Activity, University of Jyvaeskylae, Jyvaeskylae (Finland)

    2001-04-01

    Muscle blood flow has been shown to be heterogeneous at the voxel by voxel level in positron emission tomography (PET) studies using oxygen-15 labelled water. However, the limited spatial resolution of the imaging device does not allow direct measurement of true vascular flow heterogeneity. Fractal dimension (D) obtained by fractal analysis describes the relationship between the relative dispersion and the size of the region studied, and has been used for the assessment of perfusion heterogeneity in microvascular units. This study was undertaken to evaluate fractal characteristics of PET perfusion data and to estimate perfusion heterogeneity in microvascular units. Skeletal muscle blood flow was measured in healthy subjects using [{sup 15}O]water PET and the fractal characteristics of blood flow in resting and exercising skeletal muscle were analysed. The perfusion heterogeneity in microvascular units was estimated using the measured heterogeneity (relative dispersion, RD=SD/mean) and D values. Heterogeneity due to methodological factors was estimated with phantoms and subtracted from the flow data. The number of aggregated voxels was inversely correlated with RD both in phantoms (Pearson r=-0.96-0.97) and in muscle (Pearson r=-0.94) when both parameters were expressed using a logarithmic scale. Fractal dimension was similar between exercising (1.13) and resting (1.14) muscles and significantly lower than the values in the phantoms with different activity levels (1.27-1.29). Measured flow heterogeneity values were 20%{+-}6% (exercise) and 27%{+-}5% (rest, P<0.001), whereas estimated flow heterogeneity values in microvascular units (1 mm{sup 3}) were 35%{+-}14% (exercise) and 49%{+-}14% (rest, P<0.01). In conclusion, these results show that it is feasible to apply fractal analysis to PET perfusion data. When microvascular flow heterogeneity is estimated using fractals, perfusion appears to be more heterogeneous in microvascular units than when obtained by routine

  13. Enhanced Visualization of Optimal Cerebral Perfusion Pressure Over Time to Support Clinical Decision Making

    NARCIS (Netherlands)

    Aries, Marcel J H; Wesselink, Robin; Elting, Jan Willem J; Donnelly, Joseph; Czosnyka, Marek; Ercole, Ari; Maurits, Natasha M; Smielewski, Peter

    2016-01-01

    OBJECTIVE: Cerebrovascular reactivity can provide a continuously updated individualized target for management of cerebral perfusion pressure, termed optimal cerebral perfusion pressure. The objective of this project was to find a way of improving the optimal cerebral perfusion pressure methodology b

  14. 4D micro-CT for cardiac and perfusion applications with view under sampling

    Energy Technology Data Exchange (ETDEWEB)

    Badea, Cristian T; Johnston, Samuel M; Qi Yi; Johnson, G Allan, E-mail: Cristian.Badea@duke.edu [Center for In Vivo Microscopy, Box 3302, Duke University Medical Center, Durham, NC 27710 (United States)

    2011-06-07

    voxel size of 88 {mu}m and 10 ms temporal resolution. 4D pulmonary perfusion images were obtained in a mouse at 176 {mu}m and 687 ms temporal resolution. Compared with FBP reconstruction, the streak reduction ratio is 70% and the contrast to noise ratio is 2.5 times greater in the deconvolved images. The radiation dose associated with the proposed methods is in the range of a typical micro-CT dose (0.17 Gy for the cardiac study and 0.21 Gy for the perfusion study). The low dose 4D micro-CT imaging presented here can be applied in high-throughput longitudinal studies in a wide range of applications, including drug safety and cardiopulmonary phenotyping.

  15. Hepatic perfusion disorders: Etiopathogenesis and related diseases

    Institute of Scientific and Technical Information of China (English)

    Jin-Lin Tian; Jin-Shan Zhang

    2006-01-01

    In this article, we have reviewed the hepatic perfusion disorder (HPD), etiopathogenesis of HPD and corresponding diseases. Review of the literature was based on computer searches (PubMed, Index Medicus)and personal experiences. We considered HPD reflects perfusion differences due to redistribution of arterial blood flow among segments, subsegments and lobes of the liver. The plain CT scan findings of HPD manifests as triangular or wedge-shaped areas of low attenuation.On contrast-enhanced CT scan, HPD manifests multiple (or single) transient wedge-shaped, rotundloid or irregular appearance, homogeneous hyperattenuation (in less cases, hypoattenuation) during the hepatic arterial phase (HAP) and isoattenuated or slightly hyperattenuated areas during the portal arterial phase.Dynamic enhanced magnetic resonance (MR) features are similar to enhanced CT scan. Angiographic findings include non-opacification of portal vein on portograms or wedge-shaped segmental staining in arterial and parenchymal phases on hepatic angiograms. The causes of HPD are arterioportal shunts (APS), intrahepatic vascular compressions and portal vein occlusion,steal phenomenon by hypervascular tumors, vascular variations and any other unknown reasons. It is very important for radiologists to be familiar with the various appearances of HPD to avoid false-positive diagnosis of pseudolesions and not to overestimate the extent of the disease.

  16. Diffusion and perfusion imaging of bone marrow

    Energy Technology Data Exchange (ETDEWEB)

    Biffar, Andreas; Dietrich, Olaf [Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, LMU University Hospitals, Grosshadern-Munich (Germany); Sourbron, Steven [Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, LMU University Hospitals, Grosshadern-Munich (Germany); Division of Medical Physics, University of Leeds, Leeds (United Kingdom); Duerr, Hans-Roland [Department of Orthopedic Surgery, LMU University Hospitals, Grosshadern-Munich (Germany); Reiser, Maximilian F. [Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, LMU University Hospitals, Grosshadern-Munich (Germany); Department of Clinical Radiology, LMU University Hospitals, Grosshadern-Munich (Germany); Baur-Melnyk, Andrea, E-mail: andrea.baur@med.uni-muenchen.de [Department of Clinical Radiology, LMU University Hospitals, Grosshadern-Munich (Germany)

    2010-12-15

    In diffusion-weighted magnetic resonance imaging (DWI), the observed MRI signal intensity is attenuated by the self-diffusion of water molecules. DWI provides information about the microscopic structure and organization of a biological tissue, since the extent and orientation of molecular motion is influenced by these tissue properties. The most common method to measure perfusion in the body using MRI is T1-weighted dynamic contrast enhancement (DCE-MRI). The analysis of DCE-MRI data allows determining the perfusion and permeability of a biological tissue. DWI as well as DCE-MRI are established techniques in MRI of the brain, while significantly fewer studies have been published in body imaging. In recent years, both techniques have been applied successfully in healthy bone marrow as well as for the characterization of bone marrow alterations or lesions; e.g., DWI has been used in particular for the differentiation of benign and malignant vertebral compression fractures. In this review article, firstly a short introduction to diffusion-weighted and dynamic contrast-enhanced MRI is given. Non-quantitative and quantitative approaches for the analysis of DWI and semiquantitative and quantitative approaches for the analysis of DCE-MRI are introduced. Afterwards a detailed overview of the results of both techniques in healthy bone marrow and their applications for the diagnosis of various bone-marrow pathologies, like osteoporosis, bone tumors, and vertebral compression fractures are described.

  17. Non-invasive monitoring of peripheral perfusion: an exploration of non-invasive peripheral perfusion monitoring for applications in research & healthcare

    OpenAIRE

    Blaxter, Laurence

    2015-01-01

    The need for real-time, prognostic perfusion data has been widely recognised in clinical practice and academia. Perfusion, the volumetric blood low to tissue, is an important tool for haemodynamic monitoring, since perfusion adequacy is vital to tissue health. Perfusion can serve as both a diagnostic indicator and a fundamental research tool. However, lack of a low cost, easily applied, and non-invasive sensor technology capable of measuring peripheral perfusion in absolute volumetric units i...

  18. Lipid peroxidation products in machine perfusion of older donor kidneys

    NARCIS (Netherlands)

    Nagelschmidt, Manfred; Minor, Thomas; Gallinat, Anja; Moers, Cyril; Jochmans, Ina; Pirenne, Jacques; Ploeg, Rutger J.; Paul, Andreas; Treckmann, Juergen

    2013-01-01

    Background: Owing to the shortage of donors, organs with an increased risk potential such as grafts recovered from expanded criteria donors are increasingly being used in transplants. Machine perfusion (MP) technology offers the possibility of determining the biomarkers in the perfusion solution so

  19. High speed perfusion imaging based on laser speckle fluctuations

    NARCIS (Netherlands)

    Draijer, Matthijs Johannes

    2010-01-01

    Noninvasive methods to visualize blood flow in tissue are important in the clinical environment. Most methods use dynamic speckles to measure the level of perfusion. The most well-known techniques based on these speckle patterns are laser Doppler perfusion imaging (LDPI) and laser speckle contrast a

  20. Perfusion computed tomography evaluation of angiogenesis in liver cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Han Feng [Xuanwu Hospital, Capital Medical University, Department of Clinical Pain, Beijing (China); Hospital of North Sichuan Medical College, Department of Radiology, Nanchong City, Sichuan Province (China); Du, Yong; Xu, Xiao Xue; Li, Yang [Hospital of North Sichuan Medical College, Department of Radiology, Nanchong City, Sichuan Province (China); Ni, Jia Xiang [Xuanwu Hospital, Capital Medical University, Department of Clinical Pain, Beijing (China); Zhou, Xiang Ping [West China Hospital, Sichuan University, Department of Radiology, Chengdu City, Sichuan Province (China); Li, Jin Dong [Hospital of North Sichuan Medical College, Department of General Surgery, Nanchong City, Sichuan Province (China); Zhang, Qing [Hospital of North Sichuan Medical College, Department of Ultrasound, Nanchong City, Sichuan Province (China)

    2010-06-15

    To investigate the value of computed tomography (CT) perfusion imaging for assessment of angiogenesis in liver cancer. Twenty-one patients with histologically proven liver cancer underwent CT perfusion examination. We compared the following perfusion parameters in the tumour area versus the non-tumour area: total blood flow (TBF), hepatic arterial perfusion (HAP), hepatic portal perfusion (HPP) and hepatic arterial perfusion index (HAPI). Slices of postoperative specimen were stained with haematoxylin-eosin and anti-CD34 immunohistochemistry. The slices were evaluated with emphasis on the CD34-positive neovasculature in the tumour parenchyma. Tumour microvascular density (MVD) was calculated according to the Weidner method. Pearson correlation was used to detect correlations between tumour MVD and tumour perfusion parameters. TBF and HPP in the tumour area were lower than in the non-tumour area (P < 0.05). HAP and HAPI in the tumour area were higher than those of the non-tumour area (P < 0.05). TBF and HAP in the tumour area correlated with MVD in the tumour (P < 0.05), with correlation coefficients of 0.849 and 0.829, respectively. CT perfusion imaging can quantitatively assess the blood supply and its distribution in liver cancer. TBF or HAP may be a useful parameter in assessing angiogenesis of liver cancer. (orig.)

  1. Magnetic Resonance Perfusion Imaging in the Study of Language

    Science.gov (United States)

    Hillis, Argye E.

    2007-01-01

    This paper provides a brief review of various uses of magnetic resonance perfusion imaging in the investigation of brain/language relationships. The reviewed studies illustrate how perfusion imaging can reveal areas of brain where dysfunction due to low blood flow is associated with specific language deficits, and where restoration of blood flow…

  2. Method, apparatus and software for analyzing perfusion images

    NARCIS (Netherlands)

    Spreeuwers, Lieuwe Jan; Breeuwer, Marcel

    2007-01-01

    The invention relates to a method for analyzing perfusion images, in particular MR pertbsion images, of a human or animal organ including the steps of: (a) defining at least one contour of the organ, and (b) establishing at least one perfusion parameter of a region of interest of said organ within a

  3. Method, apparatus and software for analyzing perfusion images

    NARCIS (Netherlands)

    Spreeuwers, Lieuwe Jan; Breeuwer, Marcel

    2004-01-01

    The invention relates to a method for analyzing perfusion images, in particular MR pertbsion images, of a human or animal organ including the steps of: (a) defining at least one contour of the organ, and (b) establishing at least one perfusion parameter of a region of interest of said organ within a

  4. Perfusion MR imaging for differentiation of benign and malignant meningiomas

    NARCIS (Netherlands)

    Zhang, Hao; Rodiger, Lars A.; Shen, Tianzhen; Miao, Jingtao; Oudkerk, Matthijs

    2008-01-01

    Introduction Our purpose was to determine whether perfusion MR imaging can be used to differentiate benign and malignant meningiomas on the basis of the differences in perfusion of tumor parenchyma and/or peritumoral edema. Methods A total of 33 patients with preoperative meningiomas (25 benign and

  5. A model system for perfusion quantification using FAIR

    DEFF Research Database (Denmark)

    Andersen, I.K.; Sidaros, Karam; Gesmar, H

    2000-01-01

    Flow-sensitive experiments (FAIR) have been performed on a tube-flow phantom in order to validate quantitative perfusion measurements on humans. A straight-forward correspondence between perfusion and bulk-flow is found. It is shown that the flow phantom model only holds when the slice profiles...

  6. Hypothermic Machine Perfusion of Kidney Grafts: Which Pressure is Preferred?

    NARCIS (Netherlands)

    B.M. Doorschodt; M.C.J.M. Schreinemachers; M. Behbahani; S. Florquin; J. Weis; M. Staat; R.H. Tolba

    2011-01-01

    To assess the effect of the perfusion pressure (PP) during machine perfusion (MP) on the preservation quality of kidney grafts, we compared mean PPs of 25 and 30 mmHg using a porcine autotransplantation model. After assessment of the microcirculation, animals underwent left nephrectomy. Thereafter,

  7. Tissue-specific sparse deconvolution for brain CT perfusion.

    Science.gov (United States)

    Fang, Ruogu; Jiang, Haodi; Huang, Junzhou

    2015-12-01

    Enhancing perfusion maps in low-dose computed tomography perfusion (CTP) for cerebrovascular disease diagnosis is a challenging task, especially for low-contrast tissue categories where infarct core and ischemic penumbra usually occur. Sparse perfusion deconvolution has been recently proposed to effectively improve the image quality and diagnostic accuracy of low-dose perfusion CT by extracting the complementary information from the high-dose perfusion maps to restore the low-dose using a joint spatio-temporal model. However the low-contrast tissue classes where infarct core and ischemic penumbra are likely to occur in cerebral perfusion CT tend to be over-smoothed, leading to loss of essential biomarkers. In this paper, we propose a tissue-specific sparse deconvolution approach to preserve the subtle perfusion information in the low-contrast tissue classes. We first build tissue-specific dictionaries from segmentations of high-dose perfusion maps using online dictionary learning, and then perform deconvolution-based hemodynamic parameters estimation for block-wise tissue segments on the low-dose CTP data. Extensive validation on clinical datasets of patients with cerebrovascular disease demonstrates the superior performance of our proposed method compared to state-of-art, and potentially improve diagnostic accuracy by increasing the differentiation between normal and ischemic tissues in the brain.

  8. Scintigraphic assessment of distal extremity perfusion in 17 patients.

    Science.gov (United States)

    Goggin, J M; Hoskinson, J J; Carpenter, J W; Roush, J K; McLaughlin, R M; Anderson, D E

    1997-01-01

    To assess the role of scintigraphic evaluation of distal limb perfusion, the medical records and scintigraphic perfusion images of 17 animals (8 dogs, 2 cats, 2 calves, 4 birds and 1 ferret) with clinical signs of distal limb ischemia were examined retrospectively. Images were obtained at 5 and 10 minutes following injection of 99mTc-MDP, or 99mTc-DTPA. The initial scintigraphic diagnoses of 17 animals included complete ischemia (8/17), partially reduced perfusion (5/17), and normal to increased perfusion (4/17). In 4 of the animals with partially reduced perfusion, follow-up scans indicated progression to complete ischemia (1/4) or normal to increased perfusion (3/4). Nine of 17 animals had a final scintigraphic diagnosis of complete distal limb ischemia, and these animals were either euthanized (5/9) or had limb amputation (4/9). A final diagnosis of complete ischemia was supported with either repeat scanning (3/10), continued clinical observation (6/10) and/or pathological examination (10/10). Clinical signs of ischemia resolved in all (7/17) animals with increased or normal perfusion on their final scan. Scintigraphy provided a safe and noninvasive assessment of distal limb perfusion, which corresponded with clinical outcome.

  9. Lipid peroxidation products in machine perfusion of older donor kidneys

    NARCIS (Netherlands)

    Nagelschmidt, Manfred; Minor, Thomas; Gallinat, Anja; Moers, Cyril; Jochmans, Ina; Pirenne, Jacques; Ploeg, Rutger J.; Paul, Andreas; Treckmann, Juergen

    Background: Owing to the shortage of donors, organs with an increased risk potential such as grafts recovered from expanded criteria donors are increasingly being used in transplants. Machine perfusion (MP) technology offers the possibility of determining the biomarkers in the perfusion solution so

  10. [Ocular perfusion pressure and its relevance for glaucoma].

    Science.gov (United States)

    Schmidl, D; Werkmeister, R; Garhöfer, G; Schmetterer, L

    2015-02-01

    Ocular perfusion pressure is defined as the difference between arterial and venous pressure in ocular vessels. In practice, mean arterial pressure is used to substitute for arterial pressure in ocular vessels while intraocular pressure gives an estimate for ocular venous pressure. This results in a value that is easy to calculate and which is of importance since several studies have shown that it is correlated to the prevalence, incidence and progression of primary open angle glaucoma. Today, ocular perfusion pressure is used to estimate individual risks. Since no target value for ocular perfusion pressure can be defined, direct therapeutic intervention is difficult. Still, it has to be kept in mind that lowering intraocular pressure automatically leads to an increase in ocular perfusion pressure. The present article also points out problems and limitations in the concept of ocular perfusion pressure and suggests possible solutions for these problems in the future.

  11. A model system for perfusion quantification using FAIR

    DEFF Research Database (Denmark)

    Andersen, I.K.; Sidaros, Karam; Gesmar, H

    2000-01-01

    of the involved RF pulses are taken into account. A small flow-independent off-set may be present in the data. The off-set is explained by the model. Based on the correspondence between the phantom and the in vivo models, it is shown that the lowest flow values that could be measured in the phantom correspond...... to perfusion values lower than the cortical perfusion in the brain. Thus, the experimental accuracy and the computational methods for quantitative perfusion measurements in vivo can be validated by a tube-flow phantom......Flow-sensitive experiments (FAIR) have been performed on a tube-flow phantom in order to validate quantitative perfusion measurements on humans. A straight-forward correspondence between perfusion and bulk-flow is found. It is shown that the flow phantom model only holds when the slice profiles...

  12. A model system for perfusion quantification using FAIR

    DEFF Research Database (Denmark)

    Andersen, Irene Klærke; Sidaros, Karam; Gesmar, Henrik

    2000-01-01

    of the involved RF pulses are taken into account. A small flow-independent off-set may be present in the data. The off-set is explained by the model. Based on the correspondence between the phantom and the in vivo models, it is shown that the lowest flow values that could be measured in the phantom correspond...... to perfusion values lower than the cortical perfusion in the brain. Thus, the experimental accuracy and the computational methods for quantitative perfusion measurements in vivo can be validated by a tube-flow phantom.......Flow-sensitive experiments (FAIR) have been performed on a tube-flow phantom in order to validate quantitative perfusion measurements on humans. A straight-forward correspondence between perfusion and bulk-flow is found. It is shown that the flow phantom model only holds when the slice profiles...

  13. Impedance plethysmography: a new method for continuous muscle perfusion monitoring.

    Science.gov (United States)

    Concannon, M J; Stewart, D H; Welsh, C F; Puckett, C L

    1991-08-01

    Vigilant postoperative monitoring of the buried muscle flap is critical after free transfer because early diagnosis of vascular insufficiency is essential to allow prompt correction. We have identified a monitoring method utilizing needle electrodes and impedance plethysmography that gives a beat-to-beat representation of muscular perfusion. In 25 New Zealand White rabbits the gastrocnemius muscle was isolated on its vascular pedicle, and two intramuscular needle electrodes were placed. The instantaneous impedance changes of the muscle (corresponding to the pulsatile volume changes of perfusion) were measured and recorded. Using this representation of perfusion, an independent judge was able to correctly diagnose muscular ischemia 100 percent of the time (n = 25). Further, the judge was able to correctly distinguish the ischemia as arterial (n = 10) or venous (n = 10) in origin 100 percent of the time. Additionally, we monitored muscle perfusion transcutaneously in five free muscle flaps and demonstrated a reliable impedance signal that correlated with perfusion.

  14. Assessment of the spatial pattern of colorectal tumour perfusion estimated at perfusion CT using two-dimensional fractal analysis

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Vicky; Sanghera, Bal [Mount Vernon Hospital, Paul Strickland Scanner Centre, Northwood, Middlesex (United Kingdom); Wellsted, David M.; Sundin, Josefin [University of Hertfordshire, Research and Development Support Unit, Hatfield (United Kingdom); Halligan, Steve [University College Hospital, Department of Academic Radiology, London (United Kingdom)

    2009-06-15

    The aim was to evaluate the feasibility of fractal analysis for assessing the spatial pattern of colorectal tumour perfusion at dynamic contrast-enhanced CT (perfusion CT). Twenty patients with colorectal adenocarcinoma underwent a 65-s perfusion CT study from which a perfusion parametric map was generated using validated commercial software. The tumour was identified by an experienced radiologist, segmented via thresholding and fractal analysis applied using in-house software: fractal dimension, abundance and lacunarity were assessed for the entire outlined tumour and for selected representative areas within the tumour of low and high perfusion. Comparison was made with ten patients with normal colons, processed in a similar manner, using two-way mixed analysis of variance with statistical significance at the 5% level. Fractal values were higher in cancer than normal colon (p {<=} 0.001): mean (SD) 1.71 (0.07) versus 1.61 (0.07) for fractal dimension and 7.82 (0.62) and 6.89 (0.47) for fractal abundance. Fractal values were lower in 'high' than 'low' perfusion areas. Lacunarity curves were shifted to the right for cancer compared with normal colon. In conclusion, colorectal cancer mapped by perfusion CT demonstrates fractal properties. Fractal analysis is feasible, potentially providing a quantitative measure of the spatial pattern of tumour perfusion. (orig.)

  15. Determination of an adequate perfusion pressure for continuous dual vessel hypothermic machine perfusion of the rat liver

    NARCIS (Netherlands)

    't Hart, Nils A.; der van Plaats, Arjan; Leuvenink, Henri G. D.; van Goor, Harry; Wiersema-Buist, Janneke; Verkerke, Gijsbertus J.; Rakhorst, Gerhard; Ploeg, Rutger J.

    Hypothermic machine perfusion (HMP) provides better protection against ischemic damage of the kidney compared to cold-storage. The required perfusion pressures needed for optimal HMP of the liver are, however, unknown. Rat livers were preserved in University of Wisconsin organ preservation solution

  16. Tumor perfusion increases during hypofractionated short-course radiotherapy in rectal cancer : Sequential perfusion-CT findings

    NARCIS (Netherlands)

    Janssen, Marco H. M.; Aerts, Hugo J. W. L.; Kierkels, Roel G. J.; Backes, Walter H.; Ollers, Michel C.; Buijsen, Jeroen; Lambin, Philippe; Lammering, Guido

    2010-01-01

    Purpose: The purpose of this study was to investigate perfusion of rectal tumors and to determine early responses to short-course hypofractionated radiotherapy (RT). Material and methods: Twenty-three rectal cancer patients were included, which underwent perfusion-CT imaging before (pre-scan) and af

  17. Quantitative Myocardial Perfusion with Dynamic Contrast-Enhanced Imaging in MRI and CT: Theoretical Models and Current Implementation

    Directory of Open Access Journals (Sweden)

    G. J. Pelgrim

    2016-01-01

    Full Text Available Technological advances in magnetic resonance imaging (MRI and computed tomography (CT, including higher spatial and temporal resolution, have made the prospect of performing absolute myocardial perfusion quantification possible, previously only achievable with positron emission tomography (PET. This could facilitate integration of myocardial perfusion biomarkers into the current workup for coronary artery disease (CAD, as MRI and CT systems are more widely available than PET scanners. Cardiac PET scanning remains expensive and is restricted by the requirement of a nearby cyclotron. Clinical evidence is needed to demonstrate that MRI and CT have similar accuracy for myocardial perfusion quantification as PET. However, lack of standardization of acquisition protocols and tracer kinetic model selection complicates comparison between different studies and modalities. The aim of this overview is to provide insight into the different tracer kinetic models for quantitative myocardial perfusion analysis and to address typical implementation issues in MRI and CT. We compare different models based on their theoretical derivations and present the respective consequences for MRI and CT acquisition parameters, highlighting the interplay between tracer kinetic modeling and acquisition settings.

  18. Estimation of tissue perfusion by dynamic contrast-enhanced imaging: simulation-based evaluation of the steepest slope method

    Energy Technology Data Exchange (ETDEWEB)

    Brix, Gunnar [Federal Office for Radiation Protection, Department of Medical and Occupational Radiation Protection, Oberschleissheim (Germany); Bundesamt fuer Strahlenschutz, Abteilung fuer Medizinischen und Beruflichen Strahlenschutz, Oberschleissheim (Germany); Zwick, Stefan [German Cancer Research Center (DKFZ), Department of Medical Physics in Radiology, Heidelberg (Germany); University Hospital Freiburg, Department of Radiology, Medical Physics, Freiburg (Germany); Griebel, Juergen [Federal Office for Radiation Protection, Department of Medical and Occupational Radiation Protection, Oberschleissheim (Germany); Fink, Christian [University Medical Center Mannheim, University of Heidelberg, Institute of Clinical Radiology and Nuclear Medicine, Mannheim (Germany); Kiessling, Fabian [RWTH-Aachen University, Department of Experimental Molecular Imaging, Aachen (Germany)

    2010-09-15

    Tissue perfusion is frequently determined from dynamic contrast-enhanced CT or MRI image series by means of the steepest slope method. It was thus the aim of this study to systematically evaluate the reliability of this analysis method on the basis of simulated tissue curves. 9600 tissue curves were simulated for four noise levels, three sampling intervals and a wide range of physiological parameters using an axially distributed reference model and subsequently analysed by the steepest slope method. Perfusion is systematically underestimated with errors becoming larger with increasing perfusion and decreasing intravascular volume. For curves sampled after rapid contrast injection with a temporal resolution of 0.72 s, the bias was less than 23% when the mean residence time of tracer molecules in the intravascular distribution space was greater than 6 s. Increasing the sampling interval and the noise level substantially reduces the accuracy and precision of estimates, respectively. The steepest slope method allows absolute quantification of tissue perfusion in a computationally simple and numerically robust manner. The achievable degree of accuracy and precision is considered to be adequate for most clinical applications. (orig.)

  19. Resolution propositions; Proposition de resolution

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-05-01

    To put a resolution to the meeting in relation with the use of weapons made of depleted uranium is the purpose of this text. The situation of the use of depleted uranium by France during the Gulf war and other recent conflicts will be established. This resolution will give the most strict recommendations face to the eventual sanitary and environmental risks in the use of these kind of weapons. (N.C.)

  20. Intra-Arterial MR Perfusion Imaging of Meningiomas: Comparison to Digital Subtraction Angiography and Intravenous MR Perfusion Imaging

    Science.gov (United States)

    Martin, Alastair J.; Alexander, Matthew D.; McCoy, David B.; Cooke, Daniel L.; Lillaney, Prasheel; Moftakhar, Parham; Amans, Matthew R.; Settecase, Fabio; Nicholson, Andrew; Dowd, Christopher F.; Halbach, Van V.; Higashida, Randall T.; McDermott, Michael W.; Saloner, David; Hetts, Steven W.

    2016-01-01

    Background and Purpose To evaluate the ability of IA MR perfusion to characterize meningioma blood supply. Methods Studies were performed in a suite comprised of an x-ray angiography unit and 1.5T MR scanner that permitted intraprocedural patient movement between the imaging modalities. Patients underwent intra-arterial (IA) and intravenous (IV) T2* dynamic susceptibility MR perfusion immediately prior to meningioma embolization. Regional tumor arterial supply was characterized by digital subtraction angiography and classified as external carotid artery (ECA) dural, internal carotid artery (ICA) dural, or pial. MR perfusion data regions of interest (ROIs) were analyzed in regions with different vascular supply to extract peak height, full-width at half-maximum (FWHM), relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), and mean transit time (MTT). Linear mixed modeling was used to identify perfusion curve parameter differences for each ROI for IA and IV MR imaging techniques. IA vs. IV perfusion parameters were also directly compared for each ROI using linear mixed modeling. Results 18 ROIs were analyzed in 12 patients. Arterial supply was identified as ECA dural (n = 11), ICA dural (n = 4), or pial (n = 3). FWHM, rCBV, and rCBF showed statistically significant differences between ROIs for IA MR perfusion. Peak Height and FWHM showed statistically significant differences between ROIs for IV MR perfusion. RCBV and MTT were significantly lower for IA perfusion in the Dural ECA compared to IV perfusion. Relative CBF in IA MR was found to be significantly higher in the Dural ICA region and MTT significantly lower compared to IV perfusion. PMID:27802268

  1. Feasibility of 3D Partially Parallel Acquisition DCE MRI in Pulmonary Parenchyma Perfusion%三维并行采集动态增强MRI在肺实质局部灌注中的应用研究

    Institute of Scientific and Technical Information of China (English)

    夏艺; 范丽; 刘士远; 管宇; 徐雪原; 于红; 肖湘生

    2012-01-01

    . 74, P < 0. 05 ) between two groups. In other 25 cases, all lesions showed hypo-intensity when pulmonary parenchyma was enhanced to peak during the first-pass of contrast agent through the pulmonary circulation. Conclusion 3D partially parallel acquisition DCE-MRI could obtain the volumetric perfusion imaging of the whole lung. Semi quantitative analysis could improve the detection of perfusion abnormality.

  2. Perfusion Pressure Cerebral Infarct (PPCI) trial

    DEFF Research Database (Denmark)

    Vedel, Anne G.; Holmgaard, Frederik; Rasmussen, Lars Simon

    2016-01-01

    to be caused by emboli, but inadequate blood flow caused by other mechanisms may increase ischaemia in the penumbra or cause watershed infarcts. During cardiopulmonary bypass, blood pressure can be below the lower limit of cerebral autoregulation. Although much debated, the constant blood flow provided...... by the cardiopulmonary bypass system is still considered by many as appropriate to avoid cerebral ischaemia despite the low blood pressure. Methods/design: The Perfusion Pressure Cerebral Infarct trial is a single-centre superiority trial with a blinded outcome assessment. The trial is randomising 210 patients...... with coronary vessel and/or valve disease and who are undergoing cardiac surgery with the use of cardiopulmonary bypass. Patients are stratified by age and surgical procedure and are randomised 1:1 to either an increased mean arterial pressure (70–80 mmHg) or ‘usual practice’ (40–50 mmHg) during cardiopulmonary...

  3. Perfused human organs versus Mary Shelley's Frankenstein

    Directory of Open Access Journals (Sweden)

    Leung Lawrence

    2009-01-01

    Full Text Available Abstract Novel drugs have to go through mandatory pre-clinical testing before they can be approved for use in clinical trials. In essence, it is a form of bench-to-bedside (N2B translational medicine, but the wastage rate of target candidates is immensely high. Effects seen in vitro often do not translate to in vivo human settings. The search is on for better models closer to human physiology to be used in pre-clinical drug screening. The Ex Vivo Metrics© system has been introduced where a human organ is harvested and revitalized in a controlled environment suitable for testing of both drug efficacy and potential toxicity. This commentary expresses the author's views regarding this technology of perfused human organs.

  4. Perfused human organs versus Mary Shelley's Frankenstein.

    Science.gov (United States)

    Leung, Lawrence

    2009-01-23

    Novel drugs have to go through mandatory pre-clinical testing before they can be approved for use in clinical trials. In essence, it is a form of bench-to-bedside (N2B) translational medicine, but the wastage rate of target candidates is immensely high. Effects seen in vitro often do not translate to in vivo human settings. The search is on for better models closer to human physiology to be used in pre-clinical drug screening. The Ex Vivo Metrics system has been introduced where a human organ is harvested and revitalized in a controlled environment suitable for testing of both drug efficacy and potential toxicity. This commentary expresses the author's views regarding this technology of perfused human organs.

  5. Perfusion CT of head and neck cancer

    Energy Technology Data Exchange (ETDEWEB)

    Razek, Ahmed Abdel Khalek Abdel, E-mail: arazek@mans.edu.eg; Tawfik, Ahmed Mohamed, E-mail: ahm_m_tawfik@hotmail.com; Elsorogy, Lamiaa Galal Ali, E-mail: lamia2elsorogy@hotmail.com; Soliman, Nermin Yehia, E-mail: nermin_eid@hotmail.com

    2014-03-15

    We aim to review the technique and clinical applications of perfusion CT (PCT) of head and neck cancer. The clinical value of PCT in the head and neck includes detection of head and neck squamous cell carcinoma (HNSCC) as it allows differentiation of HNSCC from normal muscles, demarcation of tumor boundaries and tumor local extension, evaluation of metastatic cervical lymph nodes as well as determination of the viable tumor portions as target for imaging-guided biopsy. PCT has been used for prediction of treatment outcome, differentiation between post-therapeutic changes and tumor recurrence as well as monitoring patient after radiotherapy and/or chemotherapy. PCT has a role in cervical lymphoma as it may help in detection of response to chemotherapy and early diagnosis of relapsing tumors.

  6. Hydrogels for Engineering of Perfusable Vascular Networks.

    Science.gov (United States)

    Liu, Juan; Zheng, Huaiyuan; Poh, Patrina S P; Machens, Hans-Günther; Schilling, Arndt F

    2015-07-14

    Hydrogels are commonly used biomaterials for tissue engineering. With their high-water content, good biocompatibility and biodegradability they resemble the natural extracellular environment and have been widely used as scaffolds for 3D cell culture and studies of cell biology. The possible size of such hydrogel constructs with embedded cells is limited by the cellular demand for oxygen and nutrients. For the fabrication of large and complex tissue constructs, vascular structures become necessary within the hydrogels to supply the encapsulated cells. In this review, we discuss the types of hydrogels that are currently used for the fabrication of constructs with embedded vascular networks, the key properties of hydrogels needed for this purpose and current techniques to engineer perfusable vascular structures into these hydrogels. We then discuss directions for future research aimed at engineering of vascularized tissue for implantation.

  7. Ex vivo lung perfusion in Brazil

    Directory of Open Access Journals (Sweden)

    Luis Gustavo Abdalla

    2016-04-01

    Full Text Available Objective: To evaluate the use of ex vivo lung perfusion (EVLP clinically to prepare donor lungs for transplantation. Methods: A prospective study involving EVLP for the reconditioning of extended-criteria donor lungs, the criteria for which include aspects such as a PaO2/FiO2 ratio < 300 mmHg. Between February of 2013 and February of 2014, the lungs of five donors were submitted to EVLP for up to 4 h each. During EVLP, respiratory mechanics were continuously evaluated. Once every hour during the procedure, samples of the perfusate were collected and the function of the lungs was evaluated. Results: The mean PaO2 of the recovered lungs was 262.9 ± 119.7 mmHg at baseline, compared with 357.0 ± 108.5 mmHg after 3 h of EVLP. The mean oxygenation capacity of the lungs improved slightly over the first 3 h of EVLP-246.1 ± 35.1, 257.9 ± 48.9, and 288.8 ± 120.5 mmHg after 1, 2, and 3 h, respectively-without significant differences among the time points (p = 0.508. The mean static compliance was 63.0 ± 18.7 mmHg, 75.6 ± 25.4 mmHg, and 70.4 ± 28.0 mmHg after 1, 2, and 3 h, respectively, with a significant improvement from hour 1 to hour 2 (p = 0.029 but not from hour 2 to hour 3 (p = 0.059. Pulmonary vascular resistance remained stable during EVLP, with no differences among time points (p = 0.284. Conclusions: Although the lungs evaluated remained under physiological conditions, the EVLP protocol did not effectively improve lung function, thus precluding transplantation.

  8. Ex Situ Perfusion of Human Limb Allografts for 24 Hours.

    Science.gov (United States)

    Werner, Nicole L; Alghanem, Fares; Rakestraw, Stephanie L; Sarver, Dylan C; Nicely, Bruce; Pietroski, Richard E; Lange, Paul; Rudich, Steven M; Mendias, Christopher L; Rojas-Pena, Alvaro; Magee, John C; Bartlett, Robert H; Ozer, Kagan

    2017-03-01

    Vascularized composite allografts, particularly hand and forearm, have limited ischemic tolerance after procurement. In bilateral hand transplantations, this demands a 2 team approach and expedited transfer of the allograft, limiting the recovery to a small geographic area. Ex situ perfusion may be an alternative allograft preservation method to extend allograft survival time. This is a short report of 5 human limbs maintained for 24 hours with ex situ perfusion. Upper limbs were procured from brain-dead organ donors. Following recovery, the brachial artery was cannulated and flushed with 10 000 U of heparin. The limb was then attached to a custom-made, near-normothermic (30-33°C) ex situ perfusion system composed of a pump, reservoir, and oxygenator. Perfusate was plasma-based with a hemoglobin concentration of 4 to 6 g/dL. Average warm ischemia time was 76 minutes. Perfusion was maintained at an average systolic pressure of 93 ± 2 mm Hg, flow 310 ± 20 mL/min, and vascular resistance 153 ± 16 mm Hg/L per minute. Average oxygen consumption was 1.1 ± 0.2 mL/kg per minute. Neuromuscular electrical stimulation continually displayed contraction until the end of perfusion, and histology showed no myocyte injury. Human limb allografts appeared viable after 24 hours of near-normothermic ex situ perfusion. Although these results are early and need validation with transplantation, this technology has promise for extending allograft storage times.

  9. Influence of ocular perfusion pressure fluctuation on glaucoma

    Directory of Open Access Journals (Sweden)

    Min-Zi Ren

    2015-12-01

    Full Text Available AIM:To investigate the influence of ocular perfusion pressure fluctuation on glaucoma. METHODS:Forty patients with primary open angle glaucoma from January 2013 to June 2015 in our hospital were used as observation group and 40 families were used as control group. Circadian fluctuation of intraocular pressure, blood pressure and ocular perfusion pressure in 24h were determined to obtain systolic ocular perfusion pressure(SOPP, diastolic ocular perfusion pressure(DOPPand mean ocular perfusion pressure(MOPP. Pearson linear correlation was used to analyze the correlation of circadian MOPP fluctuation with cup-disc ratio, mean defect(MDand the picture standard deviation(PSD. RESULTS:The fluctuation of MOPP, SOPP and DOPP of observation group were significantly higher than those of control group(Pr=-0.389, 95%CI:-0.612~-0.082; P=0.011, was positively correlated with PSD(r=0.512, 95%CI:0.139 ~0.782; P=0.008; no correlation was found between it and the vertical cup-disc ratio(r=0.115, 95%CI:0.056~0.369; P=0.355. CONCLUSION:Ocular perfusion pressure fluctuations in patients with primary open angle glaucoma may reflect the severity of the disease and may make the situation aggravating. Therefore through perfusion pressure monitor in 24h may help us understand the ocular blood flow and the development of primary open-angle glaucoma.

  10. Novel Cadmium Zinc Telluride Devices for Myocardial Perfusion Imaging-Technological Aspects and Clinical Applications.

    Science.gov (United States)

    Ben-Haim, Simona; Kennedy, John; Keidar, Zohar

    2016-07-01

    Myocardial perfusion imaging plays an important role in the assessment of patients with known or suspected coronary artery disease and is well established for diagnosis and for prognostic evaluation in these patients. The dedicated cardiac SPECT cameras with solid-state cadmium zinc telluride (CZT) detectors were first introduced a decade ago. A large body of evidence is building up, showing the superiority of the new technology compared with conventional gamma cameras. Not only the CZT detectors, but also new collimator geometries, the ability to perform focused imaging optimized for the heart and advances in data processing algorithms all contribute to the significantly improved sensitivity up to 8-10 times, as well as improved energy resolution and improved reconstructed spatial resolution compared with conventional technology. In this article, we provide an overview of the physical characteristics of the CZT cameras, as well as a review of the literature published so far, including validation studies in comparison with conventional myocardial perfusion imaging and with invasive coronary angiography, significant reduction in radiation dose, and new imaging protocols enabled by the new technology.

  11. Ventilation-perfusion-chest radiography match is less likely to represent pulmonary embolism if perfusion is decreased rather than absent.

    Science.gov (United States)

    Kim, C K; Worsley, D F; Alavi, A

    2000-09-01

    The authors' goal was to determine whether the prevalence of pulmonary embolism in patients with matching ventilation-perfusion (V-Q) defects and chest radiographic opacities differs depending on the degree of perfusion deficit (absent versus decreased). The authors performed a retrospective analysis of the data obtained from the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) study. In 233 patients, angiograms were of diagnostic quality for 275 lung zones that showed matching V-Q defects and chest radiographic opacities (triple matches). Of these, V-Q scans and chest radiographs from 217 patients with triple matches in 255 lung zones were retrieved and reviewed. Areas corresponding to chest radiographic opacities were scored as having either decreased perfusion or absent perfusion by consensus. Information regarding the presence or absence of pulmonary embolism in corresponding lung zones was obtained from the PIOPED database. The overall prevalence of pulmonary embolism in all lung zones with triple matches was 27% (69 of 255). Of the 255 areas of triple matches, the perfusion was decreased in 153 (60%) and absent in 102 (40%). The prevalence of pulmonary embolism in areas of triple matches with decreased perfusion and triple matches with absent perfusion was 13% (20 of 153) and 48% (49 of 102), respectively (P = 0.0001 by the chi-square test). When these were divided further by lung zones, triple matches with decreased perfusion and triple matches with absent perfusion in the upper-middle lung zone were associated with a prevalence of 0% (O of 44), and 25% (9 of 36), respectively. The prevalence of pulmonary embolism in areas of triple matches with decreased perfusion and triple matches with absent perfusion in the lower lung zone was 18% (20 of 109), and 61% (40 of 66), respectively. A V-Q/chest radiographic match is less likely to represent pulmonary embolism if perfusion is decreased rather than absent. The overall prevalence of pulmonary

  12. PET imaging of cerebral perfusion and oxygen metabolism in stroke

    Energy Technology Data Exchange (ETDEWEB)

    Pointon, O.; Yasaka, M.; Berlangieri, S.U.; Newton, M.R.; Thomas, D.L.; Chan, C.G.; Egan, G.F.; Tochon-Danguy, H.J.; O``Keefe, G.; Donnan, G.A.; McKay, W.J. [Austin Hospital, Melbourne, VIC (Australia). Centre for PET and Depts of Nuclear Medicine and Neurology

    1998-03-01

    Full text: Stroke remains a devastating clinical event with few therapeutic options. In patients with acute stroke, we studied the cerebral perfusion and metabolic patterns with {sup 15}O-CO{sub 2} or H{sub 2}O and {sup 15}O-O{sub 2} positron emission tomography and correlated these findings to the clinical background. Forty three patients underwent 45 studies 0-23 days post-stroke (mean 7 days). Fifteen patients showed luxury perfusion (Group A), 10 had matched low perfusion and metabolism (B) and 3 showed mixed pattern including an area of misery perfusion (C). Seventeen showed no relevant abnormality (D) and there were no examples of isolated misery perfusion. Twelve of the 15 in Group A had either haemorrhagic transformation on CT, re-opening on angiography, or a cardioembolic mechanism. In contrast only 5/10 in Group B, 0/3 in Group C and 2/17 in Group D had these features. Although 7/10 in group B had moderate or large size infarcts on CT the incidence of haemorrhagic transformation was low (2/10) and significant carotid stenoses were more common in those studied (5/8) compared with the other groups. Misery perfusion was not seen beyond five days. Thus, luxury perfusion seems to be related to a cardio-embolic mechanism or reperfusion. Matched low perfusion and metabolism was associated with a low rate of haemorrhagic transformation despite a high incidence of moderate to large size infarcts. Misery perfusion is an early phenomenon in the evolution of ischaemic stroke.

  13. CT Perfusion of the Liver: Principles and Applications in Oncology

    Science.gov (United States)

    Kim, Se Hyung; Kamaya, Aya

    2014-01-01

    With the introduction of molecularly targeted chemotherapeutics, there is an increasing need for defining new response criteria for therapeutic success because use of morphologic imaging alone may not fully assess tumor response. Computed tomographic (CT) perfusion imaging of the liver provides functional information about the microcirculation of normal parenchyma and focal liver lesions and is a promising technique for assessing the efficacy of various anticancer treatments. CT perfusion also shows promising results for diagnosing primary or metastatic tumors, for predicting early response to anticancer treatments, and for monitoring tumor recurrence after therapy. Many of the limitations of early CT perfusion studies performed in the liver, such as limited coverage, motion artifacts, and high radiation dose of CT, are being addressed by recent technical advances. These include a wide area detector with or without volumetric spiral or shuttle modes, motion correction algorithms, and new CT reconstruction technologies such as iterative algorithms. Although several issues related to perfusion imaging—such as paucity of large multicenter trials, limited accessibility of perfusion software, and lack of standardization in methods—remain unsolved, CT perfusion has now reached technical maturity, allowing for its use in assessing tumor vascularity in larger-scale prospective clinical trials. In this review, basic principles, current acquisition protocols, and pharmacokinetic models used for CT perfusion imaging of the liver are described. Various oncologic applications of CT perfusion of the liver are discussed and current challenges, as well as possible solutions, for CT perfusion are presented. © RSNA, 2014 Online supplemental material is available for this article. PMID:25058132

  14. Warm vs. cold perfusion techniques to rescue rodent liver grafts.

    Science.gov (United States)

    Schlegel, Andrea; Kron, Philipp; Graf, Rolf; Dutkowski, Philipp; Clavien, Pierre-Alain

    2014-12-01

    A variety of liver perfusion techniques have been proposed to protect liver grafts prior to implantation. We compared hypothermic and normothermic oxygenated perfusion techniques in a rat liver transplant model, using higher risk grafts obtained after cardiac arrest (DCD). Rat livers were subjected to 30 or 60 min in situ warm ischemia, without application of heparin. Livers were excised and stored for 4 h at 4°C, mimicking DCD organ procurement, followed by conventional organ transport. In experimental groups, DCD liver grafts received a 4 h normothermic oxygenated perfusion through the portal vein and the hepatic artery instead of cold storage. The perfusate consisted of either full blood or leukocyte-depleted blood (normothermic groups). Other livers underwent hypothermic oxygenated perfusion (HOPE) for 1 h after warm ischemia and 4 h cold storage (HOPE group). Liver injury was assessed during machine perfusion and after isolated liver reperfusion, and by orthotopic liver transplantation (OLT). DCD livers, subjected to normothermic perfusion, disclosed reduced injury and improved survival compared to cold storage after limited warm ischemia of 30 min (70%; 7/10), but failed to protect from lethal injury in grafts exposed to 60 min warm ischemia (0%; 0/10). This finding was consistent with Kupffer and endothelial cell activation in cold stored and normothermic perfused livers. In contrast, HOPE protected from hepatocyte and non-parenchymal cell injury and led to 90% (9/10) and 63% (5/8) animal survival after 30 and 60 min of donor warm ischemia, respectively. This is the first evidence that HOPE is superior to normothermic oxygenated perfusion in a clinically relevant model through modulation of the innate immunity and endothelial cell activation. Copyright © 2014 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

  15. Improved perfusion quantification in FAIR imaging by offset correction

    DEFF Research Database (Denmark)

    Sidaros, Karam; Andersen, Irene K.; Gesmar, Henrik

    2001-01-01

    Perfusion quantification using pulsed arterial spin labeling has been shown to be sensitive to the RF pulse slice profiles. Therefore, in Flow-sensitive Alternating-Inversion Recovery (FAIR) imaging the slice selective (ss) inversion slab is usually three to four times thicker than the imaging...... slice. However, this reduces perfusion sensitivity due to the increased transit delay of the incoming blood with unperturbed spins. In the present article, the dependence of the magnetization on the RF pulse slice profiles is inspected both theoretically and experimentally. A perfusion quantification...

  16. Dual-energy perfusion-CT of pancreatic adenocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Klauß, M., E-mail: miriam.klauss@med.uni-heidelberg.de [University of Heidelberg, Dpt. of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Stiller, W., E-mail: wolfram.stiller@med.uni-heidelberg.de [University of Heidelberg, Dpt. of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Pahn, G., E-mail: gregor.pahn@med.uni-heidelberg.de [University of Heidelberg, Dpt. of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Fritz, F., E-mail: franzi.fritz@cegug.org [University of Heidelberg, Dpt. of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Kieser, M., E-mail: meinhard.kieser@med.uni-heidelberg.de [University of Heidelberg, Inst. of Medical Biometry and Informatics, Im Neuenheimer Feld 305, 69120 Heidelberg (Germany); Werner, J., E-mail: jens.werner@med.uni-heidelberg.de [University of Heidelberg, Dpt. of Surgery, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Kauczor, H.U., E-mail: hans-ulrich.kauczor@med.uni-heidelberg.de [University of Heidelberg, Dpt. of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Grenacher, L., E-mail: lars.grenacher@med.uni-heidelberg.de [University of Heidelberg, Dpt. of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany)

    2013-02-15

    Purpose: To evaluate the feasibility of dual-energy CT (DECT)-perfusion of pancreatic carcinomas for assessing the differences in perfusion, permeability and blood volume of healthy pancreatic tissue and histopathologically confirmed solid pancreatic carcinoma. Materials and methods: 24 patients with histologically proven pancreatic carcinoma were examined prospectively with a 64-slice dual source CT using a dynamic sequence of 34 dual-energy (DE) acquisitions every 1.5 s (80 ml of iodinated contrast material, 370 mg/ml, flow rate 5 ml/s). 80 kV{sub p}, 140 kV{sub p}, and weighted average (linearly blended M0.3) 120 kV{sub p}-equivalent dual-energy perfusion image data sets were evaluated with a body-perfusion CT tool (Body-PCT, Siemens Medical Solutions, Erlangen, Germany) for estimating perfusion, permeability, and blood volume values. Color-coded parameter maps were generated. Results: In all 24 patients dual-energy CT-perfusion was. All carcinomas could be identified in the color-coded perfusion maps. Calculated perfusion, permeability and blood volume values were significantly lower in pancreatic carcinomas compared to healthy pancreatic tissue. Weighted average 120 kV{sub p}-equivalent perfusion-, permeability- and blood volume-values determined from DE image data were 0.27 ± 0.04 min{sup −1} vs. 0.91 ± 0.04 min{sup −1} (p < 0.0001), 0.5 ± 0.07 *0.5 min{sup −1} vs. 0.67 ± 0.05 *0.5 min{sup −1} (p = 0.06) and 0.49 ± 0.07 min{sup −1} vs. 1.28 ± 0.11 min{sup −1} (p < 0.0001). Compared with 80 and 140 kV{sub p} the standard deviations of the kV{sub p}120 kV{sub p}-equivalent values were manifestly smaller. Conclusion: Dual-energy CT-perfusion of the pancreas is feasible. The use of DECT improves the accuracy of CT-perfusion of the pancreas by fully exploiting the advantages of enhanced iodine contrast at 80 kV{sub p} in combination with the noise reduction at 140 kV{sub p}. Therefore using dual-energy perfusion data could improve the delineation

  17. CT myocardial perfusion imaging: current status and future directions.

    Science.gov (United States)

    Williams, M C; Newby, D E

    2016-08-01

    Computed tomography (CT) imaging of the heart has advanced rapidly, and it is now possible to perform a comprehensive assessment at a low radiation dose. CT myocardial perfusion imaging can provide additive information to CT coronary angiography, and is particularly useful in patients with heavily calcified coronary arteries or coronary artery stents. A number of protocols are now available for CT myocardial perfusion including static, dynamic, and dual-energy techniques. This review will discuss the current status of CT myocardial perfusion imaging, its clinical application, and future directions for this technology.

  18. Role of magnetic resonance perfusion studies in moyamoya disease

    Directory of Open Access Journals (Sweden)

    Khanna Paritosh

    2004-04-01

    Full Text Available Moyamoya disease, Japanese for ′puff of smoke′, is a rare disease that presents most commonly with recurrent TIAs (transient ischemic attacks / stroke in childhood. Ischemic symptoms in patients with moyamoya disease are usually due to hemodynamically-mediated perfusion failure. Identification of abnormal tissue perfusion is an important aspect of the evaluation of these patients. We present the radiological features including the Magnetic Resonance (MR Perfusion findings illustrating the hemodynamic changes of cerebral ischemia in a case of moyamoya disease.

  19. Conflict Resolution

    African Journals Online (AJOL)

    and shift the focus more to the social impact of growth ana away from growth .... Perspectives on, and approaches towards, conflict and conflict resolution .... transformation, and changes in values and ethical approaches (such as nepotism ... education, life expectancy, employment, childbirth survival and similar indica-.

  20. Development of an Ex Vivo, Beating Heart Model for CT Myocardial Perfusion

    NARCIS (Netherlands)

    Pelgrim, Gert Jan; Das, Marco; Haberland, Ulrike; Slump, Cees; Handayani, Astri; van Tuijl, Sjoerd; Stijnen, Marco; Klotz, Ernst; Oudkerk, Matthijs; Wildberger, Joachim E.; Vliegenthart, Rozemarijn

    2015-01-01

    Objective. To test the feasibility of a CT-compatible, ex vivo, perfused porcine heart model for myocardial perfusion CT imaging. Methods. One porcine heart was perfused according to Langendorff. Dynamic perfusion scanning was performed with a second-generation dual source CT scanner. Circulatory pa

  1. Brain Tissue Volumes and Perfusion Change with the Number of Optic Neuritis Attacks in Relapsing Neuromyelitis Optica: A Voxel-Based Correlation Study.

    Directory of Open Access Journals (Sweden)

    Carlos A Sánchez-Catasús

    Full Text Available Recent neuroimaging studies show that brain abnormalities in neuromyelitis optica (NMO are more frequent than earlier described. Yet, more research considering multiple aspects of NMO is necessary to better understand these abnormalities. A clinical feature of relapsing NMO (RNMO is that the incremental disability is attack-related. Therefore, association between the attack-related process and neuroimaging might be expected. On the other hand, the immunopathological analysis of NMO lesions has suggested that CNS microvasculature could be an early disease target, which could alter brain perfusion. Brain tissue volume changes accompanying perfusion alteration could also be expected throughout the attack-related process. The aim of this study was to investigate in RNMO patients, by voxel-based correlation analysis, the assumed associations between regional brain white (WMV and grey matter volumes (GMV and/or perfusion on one side, and the number of optic neuritis (ON attacks, myelitis attacks and/or total attacks on the other side. For this purpose, high resolution T1-weighted MRI and perfusion SPECT imaging were obtained in 15 RNMO patients. The results showed negative regional correlations of WMV, GMV and perfusion with the number of ON attacks, involving important components of the visual system, which could be relevant for the comprehension of incremental visual disability in RNMO. We also found positive regional correlation of perfusion with the number of ON attacks, mostly overlapping the brain area where the WMV showed negative correlation. This provides evidence that brain microvasculature is an early disease target and suggests that perfusion alteration could be important in the development of brain structural abnormalities in RNMO.

  2. Brain Tissue Volumes and Perfusion Change with the Number of Optic Neuritis Attacks in Relapsing Neuromyelitis Optica: A Voxel-Based Correlation Study.

    Science.gov (United States)

    Sánchez-Catasús, Carlos A; Cabrera-Gomez, José; Almaguer Melián, William; Giroud Benítez, José Luis; Rodríguez Rojas, Rafael; Bayard, Jorge Bosch; Galán, Lídice; Sánchez, Reinaldo Galvizu; Fuentes, Nancy Pavón; Valdes-Sosa, Pedro

    2013-01-01

    Recent neuroimaging studies show that brain abnormalities in neuromyelitis optica (NMO) are more frequent than earlier described. Yet, more research considering multiple aspects of NMO is necessary to better understand these abnormalities. A clinical feature of relapsing NMO (RNMO) is that the incremental disability is attack-related. Therefore, association between the attack-related process and neuroimaging might be expected. On the other hand, the immunopathological analysis of NMO lesions has suggested that CNS microvasculature could be an early disease target, which could alter brain perfusion. Brain tissue volume changes accompanying perfusion alteration could also be expected throughout the attack-related process. The aim of this study was to investigate in RNMO patients, by voxel-based correlation analysis, the assumed associations between regional brain white (WMV) and grey matter volumes (GMV) and/or perfusion on one side, and the number of optic neuritis (ON) attacks, myelitis attacks and/or total attacks on the other side. For this purpose, high resolution T1-weighted MRI and perfusion SPECT imaging were obtained in 15 RNMO patients. The results showed negative regional correlations of WMV, GMV and perfusion with the number of ON attacks, involving important components of the visual system, which could be relevant for the comprehension of incremental visual disability in RNMO. We also found positive regional correlation of perfusion with the number of ON attacks, mostly overlapping the brain area where the WMV showed negative correlation. This provides evidence that brain microvasculature is an early disease target and suggests that perfusion alteration could be important in the development of brain structural abnormalities in RNMO.

  3. Quantification of MRI measured myocardial perfusion reserve in healthy humans: a comparison with positron emission tomography

    DEFF Research Database (Denmark)

    Fritz-Hansen, Thomas; Hove, Jens D; Kofoed, Klaus F

    2008-01-01

    PURPOSE: To validate a noninvasive quantitative MRI technique, the K(i) perfusion method, for myocardial perfusion in humans using (13)N-ammonia PET as a reference method. MATERIALS AND METHODS: Ten healthy males (64 +/- 8 years) were examined with combined PET and MRI perfusion imaging at rest...... and during stress induced by dipyridamole in order to determine the myocardial perfusion reserve. Myocardial and blood time concentration curves obtained by Gd-DTPA-enhanced MRI and (13)N-ammonia PET were fitted by a two-compartment perfusion model. RESULTS: Mean perfusion values (+/-SD) derived from the MRI...... as a quantitative marker for myocardial perfusion in healthy humans....

  4. A Unifying model of perfusion and motion applied to reconstruction of sparsely sampled free-breathing myocardial perfusion MRI

    DEFF Research Database (Denmark)

    Pedersen, Henrik; Ólafsdóttir, Hildur; Larsen, Rasmus

    2010-01-01

    The clinical potential of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is currently limited by respiratory induced motion of the heart. This paper presents a unifying model of perfusion and motion in which respiratory motion becomes an integral part of myocardial perfusion...... quantification. Hence, the need for tedious manual motion correction prior to perfusion quantification is avoided. In addition, we demonstrate that the proposed framework facilitates the process of reconstructing DCEMRI from sparsely sampled data in the presence of respiratory motion. The paper focuses primarily...

  5. Computed tomography angiography and perfusion to assess coronary artery stenosis causing perfusion defects by single photon emission computed tomography

    DEFF Research Database (Denmark)

    Rochitte, Carlos E; George, Richard T; Chen, Marcus Y

    2014-01-01

    AIMS: To evaluate the diagnostic power of integrating the results of computed tomography angiography (CTA) and CT myocardial perfusion (CTP) to identify coronary artery disease (CAD) defined as a flow limiting coronary artery stenosis causing a perfusion defect by single photon emission computed...... tomography (SPECT). METHODS AND RESULTS: We conducted a multicentre study to evaluate the accuracy of integrated CTA-CTP for the identification of patients with flow-limiting CAD defined by ≥50% stenosis by invasive coronary angiography (ICA) with a corresponding perfusion deficit on stress single photon...

  6. Tracer kinetic modelling in MRI: estimating perfusion and capillary permeability

    Science.gov (United States)

    Sourbron, S. P.; Buckley, D. L.

    2012-01-01

    The tracer-kinetic models developed in the early 1990s for dynamic contrast-enhanced MRI (DCE-MRI) have since become a standard in numerous applications. At the same time, the development of MRI hardware has led to increases in image quality and temporal resolution that reveal the limitations of the early models. This in turn has stimulated an interest in the development and application of a second generation of modelling approaches. They are designed to overcome these limitations and produce additional and more accurate information on tissue status. In particular, models of the second generation enable separate estimates of perfusion and capillary permeability rather than a single parameter Ktrans that represents a combination of the two. A variety of such models has been proposed in the literature, and development in the field has been constrained by a lack of transparency regarding terminology, notations and physiological assumptions. In this review, we provide an overview of these models in a manner that is both physically intuitive and mathematically rigourous. All are derived from common first principles, using concepts and notations from general tracer-kinetic theory. Explicit links to their historical origins are included to allow for a transfer of experience obtained in other fields (PET, SPECT, CT). A classification is presented that reveals the links between all models, and with the models of the first generation. Detailed formulae for all solutions are provided to facilitate implementation. Our aim is to encourage the application of these tools to DCE-MRI by offering researchers a clearer understanding of their assumptions and requirements.

  7. Modeling and optimization of Look-Locker spin labeling for measuring perfusion and transit time changes in activation studies taking into account arterial blood volume.

    Science.gov (United States)

    Francis, S T; Bowtell, R; Gowland, P A

    2008-02-01

    This work describes a new compartmental model with step-wise temporal analysis for a Look-Locker (LL)-flow-sensitive alternating inversion-recovery (FAIR) sequence, which combines the FAIR arterial spin labeling (ASL) scheme with a LL echo planar imaging (EPI) measurement, using a multireadout EPI sequence for simultaneous perfusion and T*(2) measurements. The new model highlights the importance of accounting for the transit time of blood through the arteriolar compartment, delta, in the quantification of perfusion. The signal expected is calculated in a step-wise manner to avoid discontinuities between different compartments. The optimal LL-FAIR pulse sequence timings for the measurement of perfusion with high signal-to-noise ratio (SNR), and high temporal resolution at 1.5, 3, and 7T are presented. LL-FAIR is shown to provide better SNR per unit time compared to standard FAIR. The sequence has been used experimentally for simultaneous monitoring of perfusion, transit time, and T*(2) changes in response to a visual stimulus in four subjects. It was found that perfusion increased by 83 +/- 4% on brain activation from a resting state value of 94 +/- 13 ml/100 g/min, while T*(2) increased by 3.5 +/- 0.5%. (c) 2008 Wiley-Liss, Inc.

  8. Multislice CT brain image registration for perfusion studies

    Science.gov (United States)

    Lin, Zhong Min; Pohlman, Scott; Chandra, Shalabh

    2002-04-01

    During the last several years perfusion CT techniques have been developed as an effective technique for clinically evaluating cerebral hemodynamics. Perfusion CT techniques are capable of measurings functional parameters such as tissue perfusion, blood flow, blood volume, and mean transit time and are commonly used to evaluate stroke patients. However, the quality of functional images of the brain frequently suffers from patient head motion. Because the time window for an effective treatment of stroke patient is narrow, a fast motion correction is required. The purpose of the paper is to present a fast and accurate registration technique for motion correction of multi-slice CT and to demonstrate the effects of the registration on perfusion calculation.

  9. Displaying perfusion MRI images as color intensity projections

    CERN Document Server

    Hoefnagels, Friso; Sanchez, Ester; Lagerwaard, Frank J

    2007-01-01

    Dynamic susceptibility-weighted contrast-enhanced (DSC) MRI or perfusion-MRI plays an important role in the non-invasive assessment of tumor vascularity. However, the large number of images provided by the method makes display and interpretation of the results challenging. Current practice is to display the perfusion information as relative cerebral blood volume maps (rCBV). Color intensity projections (CIPs) provides a simple, intuitive display of the perfusion-MRI data so that regional perfusion characteristics are intrinsically integrated into the anatomy structure the T2 images. The ease of use and quick calculation time of CIPs should allow it to be easily integrated into current analysis and interpretation pipelines.

  10. Personal computer aided cerebral perfusion imaging with dynamic CT

    Institute of Scientific and Technical Information of China (English)

    林燕; 高培毅

    2004-01-01

    @@Reports on the clinical implementation of dynamic computerised tomography (CT) perfusion imaging and quantitative measurement have increased dramatically of late.1-8 The advantages of dynamic CT perfusion imaging and quantitative measurement for the diagnosis of acute cerebral infarction have been acknowledged. However, most overseas CT vendors set perfusion imaging software package as an option for graphic workstation at a too high price for domestic practitioners. To foster the domestic implementation and development of this new technology, we have extended the earlier work.1,2 Applying the theory of central volume principle to DICOM 3.0 standard forms of prime CT images, we developed dynamic CT perfusion imaging and quantitative measure-ment programmes for PCs using Visual C+ + in Windows 98 system.

  11. Prematurity and brain perfusion: Arterial spin labeling MRI

    Directory of Open Access Journals (Sweden)

    Domenico Tortora

    2017-01-01

    Conclusions: ASL MRI demonstrated differences in brain perfusion of the basal ganglia between PN and TN. In PN, a positive correlation between CBF and neuromotor outcome was demonstrated in this area.

  12. Decreased myocardial perfusion reserve in diabetic autonomic neuropathy

    DEFF Research Database (Denmark)

    Taskiran, Mustafa; Fritz-Hansen, Thomas; Rasmussen, Verner

    2002-01-01

    The pathophysiological mechanisms responsible for increased cardiovascular mortality in diabetic autonomic neuropathy are unknown. To investigate the effect of autonomic neuropathy on myocardial function, we performed dynamic contrast-enhanced magnetic resonance perfusion imaging during baseline...... conditions and after Dipyridamole-induced vasodilatation in nine type 1 diabetic patients with autonomic neuropathy (AN+), defined by cardiovascular tests, as well as in 10 type 1 diabetic patients without autonomic neuropathy (AN-) and 10 healthy control subjects. Baseline myocardial perfusion index (K...... blood pressure response to Dipyridamole and myocardial perfusion reserve index. We conclude that type 1 diabetic patients with autonomic neuropathy have a decreased myocardial perfusion reserve capacity when challenged with a vasodilatator, a finding that may in part be the pathophysiological substrate...

  13. Associations between muscle perfusion and symptoms in knee osteoarthritis

    DEFF Research Database (Denmark)

    Bandak, E; Boesen, M; Bliddal, H

    2015-01-01

    OBJECTIVE: To investigate the association between muscle perfusion in the peri-articular knee muscles assessed by dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) and symptoms in patients with knee osteoarthritis (KOA). DESIGN: In a cross-sectional setting, muscle perfusion......-MRI and clinical data were analyzed in 94 patients. The typical participant was a woman with a mean age of 65 years, and a body mass index (BMI) of 32 kg/m(2). Reduced multiple regression models analyzing the association between KOOS and DCE-MRI perfusion variables of Total Muscle Volume showed a statistically...... significant association between Nvoxel% and KOOS pain (0.41 (SE 0.14); P = 0.0048). Nvoxel% was defined as the proportion of highly perfused voxels; i.e., the voxels that show an early and rapid increase on the signal intensity vs time curves, reach a plateau state (plateau pattern) and then showing...

  14. Perfusion computed tomography to assist decision making for stroke thrombolysis

    Science.gov (United States)

    Levi, Christopher; Krishnamurthy, Venkatesh; McElduff, Patrick; Miteff, Ferdi; Spratt, Neil J.; Bateman, Grant; Donnan, Geoffrey; Davis, Stephen; Parsons, Mark

    2015-01-01

    The use of perfusion imaging to guide selection of patients for stroke thrombolysis remains controversial because of lack of supportive phase three clinical trial evidence. We aimed to measure the outcomes for patients treated with intravenous recombinant tissue plasminogen activator (rtPA) at a comprehensive stroke care facility where perfusion computed tomography was routinely used for thrombolysis eligibility decision assistance. Our overall hypothesis was that patients with ‘target’ mismatch on perfusion computed tomography would have improved outcomes with rtPA. This was a prospective cohort study of consecutive ischaemic stroke patients who fulfilled standard clinical/non-contrast computed tomography eligibility criteria for treatment with intravenous rtPA, but for whom perfusion computed tomography was used to guide the final treatment decision. The ‘real-time’ perfusion computed tomography assessments were qualitative; a large perfusion computed tomography ischaemic core, or lack of significant perfusion lesion-core mismatch were considered relative exclusion criteria for thrombolysis. Specific volumetric perfusion computed tomography criteria were not used for the treatment decision. The primary analysis compared 3-month modified Rankin Scale in treated versus untreated patients after ‘off-line’ (post-treatment) quantitative volumetric perfusion computed tomography eligibility assessment based on presence or absence of ‘target’ perfusion lesion-core mismatch (mismatch ratio >1.8 and volume >15 ml, core perfusion computed tomography-selected rtPA-treated patients to an Australian historical cohort of non-contrast computed tomography-selected rtPA-treated patients. Of 635 patients with acute ischaemic stroke eligible for rtPA by standard criteria, thrombolysis was given to 366 patients, with 269 excluded based on visual real-time perfusion computed tomography assessment. After off-line quantitative perfusion computed tomography classification

  15. Human males and females body thermoregulation: perfusion effect analysis.

    Science.gov (United States)

    Acharya, Saraswati; Gurung, D B; Saxena, V P

    2014-10-01

    Skin temperature is a common physiological parameter that reflects thermal responses. Blood perfusion is an important part of the physiological processes that the human body undergoes in order to maintain homeostasis. This study focuses on the effect of perfusion on the temperature distribution in human males and females body in different thermal environment. The study has been carried out for one dimensional steady cases using finite element method. The input parameter of the model is the blood perfusion or volumetric flow rate within the tissue. The appropriate physical and physiological parameters together with suitable boundary conditions that affect the heat regulations have been incorporated in the model. The study is to have a better understanding that how does thermoregulation change in human males and females skin layered due to perfusion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Current perspectives in transplant medicine: hypothermic oxygenated perfusion

    Directory of Open Access Journals (Sweden)

    Michel SG

    2016-11-01

    Full Text Available Sebastian G Michel,1 Joren C Madsen2,3 1Department of Cardiac Surgery, Ludwig-Maximilians-University, Munich, Germany; 2Department of Surgery, Center for Transplantation Sciences, 3Division of Cardiac Surgery, Department of Surgery, Massachusetts General Hospital, Boston, MA, USA Abstract: The purpose of this review was to provide an update on hypothermic oxygenated perfusion as a preservation technique for whole organ allografts. Clinical and experimental data in heart, lung, liver, kidney, and pancreas/islet transplantation are summarized with a special emphasis on marginal donors and donation after circulatory death. The rationale behind hypothermic machine perfusion as well as its advantages and disadvantages compared to conventional cold storage and the competing technique, normothermic machine perfusion, are reviewed. Keywords: organ transplantation, organ preservation, hypothermic perfusion

  17. Effects of acquisition time and reconstruction algorithm on image quality, quantitative parameters, and clinical interpretation of myocardial perfusion imaging

    DEFF Research Database (Denmark)

    Enevoldsen, Lotte H; Menashi, Changez A K; Andersen, Ulrik B;

    2013-01-01

    BACKGROUND: Recently introduced iterative reconstruction algorithms with resolution recovery (RR) and noise-reduction technology seem promising for reducing scan time or radiation dose without loss of image quality. However, the relative effects of reduced acquisition time and reconstruction...... software have not previously been reported. The aim of the present study was to investigate the influence of reduced acquisition time and reconstruction software on quantitative and qualitative myocardial perfusion single photon emission computed tomography (SPECT) parameters using full time (FT) and half...... time (HT) protocols and Evolution for Cardiac Software. METHODS: We studied 45 consecutive, non-selected patients referred for a clinically indicated routine 2-day stress/rest (99m)Tc-Sestamibi myocardial perfusion SPECT. All patients underwent an FT and an HT scan. Both FT and HT scans were processed...

  18. Australian and New Zealand Perfusion Survey: Management and Procedure

    Science.gov (United States)

    Tuble, Sigrid C.; Willcox, Timothy W.; Baker, Robert A.

    2009-01-01

    Abstract: In this report, we will discuss management and procedural aspects of perfusion practice. This report allows us to compare and contrast recent trends and changes in perfusion with historic practices. A survey comprised of 233 single-answer and 12 open-ended questions was sent by e-mail to senior perfusionists or individuals in charge of perfusion in 40 hospital groups. The survey encompasses a review of the perfusion practices for the calendar year of 2003, and respondents were required to answer the survey based on the predominant practice in their institutions. Standard management of routine adult cardiopulmonary bypass (CPB) in 2003 consisted of perfusion strategies that achieved a target temperature of 32.0°C (range, 28.0–35.0°C), a flow index of 2.4 L/min/m2 (range, 1.6–3.0 L/min/m2) during normothermia and 1.8 L/min/m2 (range, 1.2–3.0 L/min/m2) during hypothermia, and a pressure during CPB between 50 (range, 30–65 mmHg) and 70 mmHg (range, 60–95 mmHg). Myocardial protection with blood cardioplegia was used in 77% of the 20,688 CPB cases, whereas in 53% cases, cardiotomy blood was never processed. Pre-operatively, 76% of perfusion groups assessed their patients (21% directly with the patient), and 85% responded that perfusionists performed or participated in a formal pre-bypass checklist. The majority of the perfusion groups used a handwritten perfusion record (62%), 12% used an electronic perfusion record, and 26% used both, whereas more than one half of the groups were involved in quality assurance (79%), incident reporting (74%), audits (62%), research (53%), participating in interdisciplinary meetings (53%), and morbidity and mortality meetings (65%). Only 26% conducted formal perfusion team meetings. This report outlines the status of clinical management and procedural performance for perfusion practices in Australia and New Zealand in 2003. Awareness of these trends will allow perfusionists to assess both individual practices and

  19. Reproducibility of magnetic resonance perfusion imaging.

    Directory of Open Access Journals (Sweden)

    Xiaomeng Zhang

    Full Text Available Dynamic MR biomarkers (T2*-weighted or susceptibility-based and T1-weighted or relaxivity-enhanced have been applied to assess tumor perfusion and its response to therapies. A significant challenge in the development of reliable biomarkers is a rigorous assessment and optimization of reproducibility. The purpose of this study was to determine the measurement reproducibility of T1-weighted dynamic contrast-enhanced (DCE-MRI and T2*-weighted dynamic susceptibility contrast (DSC-MRI with two contrast agents (CA of different molecular weight (MW: gadopentetate (Gd-DTPA, 0.5 kDa and Gadomelitol (P792, 6.5 kDa. Each contrast agent was tested with eight mice that had subcutaneous MDA-MB-231 breast xenograft tumors. Each mouse was imaged with a combined DSC-DCE protocol three times within one week to achieve measures of reproducibility. DSC-MRI results were evaluated with a contrast to noise ratio (CNR efficiency threshold. There was a clear signal drop (>95% probability threshold in the DSC of normal tissue, while signal changes were minimal or non-existent (<95% probability threshold in tumors. Mean within-subject coefficient of variation (wCV of relative blood volume (rBV in normal tissue was 11.78% for Gd-DTPA and 6.64% for P792. The intra-class correlation coefficient (ICC of rBV in normal tissue was 0.940 for Gd-DTPA and 0.978 for P792. The inter-subject correlation coefficient was 0.092. Calculated K(trans from DCE-MRI showed comparable reproducibility (mean wCV, 5.13% for Gd-DTPA, 8.06% for P792. ICC of K(trans showed high intra-subject reproducibility (ICC = 0.999/0.995 and inter-subject heterogeneity (ICC = 0.774. Histograms of K(trans distributions for three measurements had high degrees of overlap (sum of difference of the normalized histograms <0.01. These results represent homogeneous intra-subject measurement and heterogeneous inter-subject character of biological population, suggesting that perfusion MRI could be an imaging biomarker to

  20. PERFUSION SYSTEM CONTROLLER STRATEGIES DURING AN ECMO SUPPORT

    OpenAIRE

    2014-01-01

    In this work modelling and control of Perfusion system is presented. The Perfusion system simultaneously controls the partial pressures during Extra Corporeal Membrane Oxygenation (ECMO) support. The main Problem in ECMO system is exchange of Blood Gases in the Artificial Lung (Oxygenator).It is a highly Nonlinear Process comprising time-varying parameters, and varying time delays, it is currently being controlled manually by trained Perfusionist. The new control strategy implemen...

  1. Perfusion Electronic Record Documentation Using Epic Systems Software.

    Science.gov (United States)

    Steffens, Thomas G; Gunser, John M; Saviello, George M

    2015-12-01

    This paper describes the design and use of Epic Systems software for documentation of perfusion activities as part of the patient electronic medical record. The University of Wisconsin Hospital and Clinics adapted the Anesthesia software module and developed an integrated perfusion/anesthesia record for the documentation of cardiac and non-cardiac surgical procedures. This project involved multiple committees, approvals, and training to successfully implement. This article will describe our documentation options, concepts, design, challenges, training, and implementation during our initial experience.

  2. Whole brain CT perfusion on a 320-slice CT scanner

    Directory of Open Access Journals (Sweden)

    Jai Jai Shiva Shankar

    2011-01-01

    Full Text Available Computed tomography perfusion (CTP has been criticized for limited brain coverage. This may result in inadequate coverage of the lesion, inadequate arterial input function, or omission of the lesion within the target perfusion volume. The availability of 320-slice CT scanners offers whole brain coverage. This minimizes the chances of misregistration of lesions regardless of location, and makes the selection of the arterial input function easy. We present different clinical scenarios in which whole brain CTP is especially useful.

  3. Three-dimensional tumor perfusion reconstruction using fractal interpolation functions.

    Science.gov (United States)

    Craciunescu, O I; Das, S K; Poulson, J M; Samulski, T V

    2001-04-01

    It has been shown that the perfusion of blood in tumor tissue can be approximated using the relative perfusion index determined from dynamic contrast-enhanced magnetic resonance imaging (DE-MRI) of the tumor blood pool. Also, it was concluded in a previous report that the blood perfusion in a two-dimensional (2-D) tumor vessel network has a fractal structure and that the evolution of the perfusion front can be characterized using invasion percolation. In this paper, the three-dimensional (3-D) tumor perfusion is reconstructed from the 2-D slices using the method of fractal interpolation functions (FIF), i.e., the piecewise self-affine fractal interpolation model (PSAFIM) and the piecewise hidden variable fractal interpolation model (PHVFIM). The fractal models are compared to classical interpolation techniques (linear, spline, polynomial) by means of determining the 2-D fractal dimension of the reconstructed slices. Using FIFs instead of classical interpolation techniques better conserves the fractal-like structure of the perfusion data. Among the two FIF methods, PHVFIM conserves the 3-D fractality better due to the cross correlation that exists between the data in the 2-D slices and the data along the reconstructed direction. The 3-D structures resulting from PHVFIM have a fractal dimension within 3%-5% of the one reported in literature for 3-D percolation. It is, thus, concluded that the reconstructed 3-D perfusion has a percolation-like scaling. As the perfusion term from bio-heat equation is possibly better described by reconstruction via fractal interpolation, a more suitable computation of the temperature field induced during hyperthermia treatments is expected.

  4. Rapid donor liver procurement with only aortic perfusion

    Institute of Scientific and Technical Information of China (English)

    Qi-Yuan Lin; KK Chui; AR-Nitin Rao

    2001-01-01

    ATM: to describe a rapid technique for procurement of donor liver with aortic perfusion only (APO). METHODS: Only the aorta is cannulated and perfused with chilled preservation solution. RESULTS: The quality of donor liver can ensure the grafted liver functions. CONCLUSION: The method of APO can simplify the operative procedure, compared with the dual cannulation. It also can minimize the danger of injuring vascular structures and involve less dissection.

  5. Assessment of lung tumor response by perfusion CT.

    Science.gov (United States)

    Coche, E

    2013-01-01

    Perfusion CT permits evaluation of lung cancer angiogenesis and response to therapy by demonstrating alterations in lung tumor vascularity. It is advocated that perfusion CT performed shortly after initiating therapy may provide a better evaluation of physiological changes rather than the conventional size assessment obtained with RECIST. The radiation dose,the volume of contrast medium delivered to the patient and the reproducibility of blood flow parameters remain an issue for this type of investigation.

  6. A Review of Liver Perfusion Method in Toxicology Studies

    Directory of Open Access Journals (Sweden)

    M karami

    2014-06-01

    Full Text Available Introduction: The isolated perfused rat liver is an accepted method in toxicology studies. The isolated perfused rat liver (IPRL is a useful experimental system for evaluating hepatic function without the influence of other organ systems, undefined plasma constituents, and neural-hormonal effects. Methods: The untreated male rats (180-220gr body weight were anesthetised with ether and then surgery with proper method. The abdomen was opened through a midline and one transversal incision and the bile duct was cannulated. Heparin sodium solution (0.5 ml; 500 U/ml in 0.9% NaCl was injected via the abdominal vena cava to prevent blood clotting. The liver inferior venacava was cannulated with PE-10 tubing and secured. The portal vein was immediately cannulated with an 23gr catheter which was secured and then liver was perfused in situ by Krebs- Henseleit buffer (pH 7.4; saturated with 95% O2 and 5% CO2; 37°C at a flow rate of 20 ml/min for 3hr. Temperature, perfusion pressure, flow rate and perfusion fluid pH were closely monitored during the perfusion. Results: Transferase enzymes (ALT, AST alterations can be widely used as a measure of biochemical alterations in order to assess liver damage due to use of drugs such as isoniazid (INH and animal and plant toxins. Accumulated material in gallbladder are valuable samples to assess the level of Glutathione (GSH. Sections of perfused liver tissue can also be effectively analyzed for pathological aspects such as necrosis, fibrosis, cellularity. Conclusion: The isolated perfused rat liver (IPRL is a useful and Sutible experimental system for evaluating hepatic function. In this system, the effects of adjacent organs, on the liver is minimized

  7. Role of Perfusion CT Differentiating Hemangiomas from Malignant Hepatic Lesions

    Directory of Open Access Journals (Sweden)

    Jagjeet Singh

    2014-01-01

    Full Text Available Objective: The purpose of the study was to determine the role of computed tomography (CT perfusion in differentiating hemangiomas from malignant hepatic lesions. Materials and Methods: This study was approved by the institutional review board. All the patients provided informed consent. CT perfusion was performed with 64 multidetector CT (MDCT scanner on 45 patients including 27 cases of metastasis, 9 cases of hepatocellular carcinoma (HCC, and 9 cases of hemangiomas. A 14 cm span of the liver was covered during the perfusion study. Data was analyzed to calculate blood flow (BF, blood volume (BV, permeability surface area product (PS, mean transit time (MTT, hepatic arterial fraction (HAF, and induced residue fraction time of onset (IRFTO. CT perfusion parameters at the periphery of lesions and background liver parenchyma were compared. Results: Significant changes were observed in the perfusion parameters at the periphery of different lesions. Of all the perfusion parameters BF, HAF, and IRFTO showed most significant changes. In our study we found: BF of more than 400 ml/100 g/min at the periphery of the hemangiomas showed sensitivity of 88.9%, specificity of 83.3%, positive predictive value (PPV of 57.1%, and negative predictive value (NPV of 96.7% in differentiating hemangiomas from hepatic malignancy; HAF of more than 60% at the periphery of hemangiomas showed sensitivity of 77.8%, specificity of 86.1%, PPV of 58.3% and NPV of 93.9% in differentiating hemangiomas from hepatic malignancy; IRFTO of more than 3 s at the periphery of hemangiomas showed sensitivity of 77.8%, specificity of 86.1%, PPV of 58.3%, and NPV of 93.9% in differentiating hemangiomas from hepatic malignancy. Conclusion: Perfusion CT is a helpful tool in differentiating hemangiomas from hepatic malignancy by its ability to determine changes in perfusion parameters of the lesions.

  8. CT perfusion image processing: analysis of liver tumors

    OpenAIRE

    D’Antò, Michela

    2013-01-01

    Perfusion CT imaging of the liver has potential to improve evaluation of tumour angiogenesis. Quantitative parameters can be obtained applying mathematical models to Time Attenuation Curve (TAC). However, there are still some difficulties for an accurate quantification of perfusion parameters due, for example, to algorithms employed, to mathematical model, to patient’s weight and cardiac output and to the acquisition system. In this thesis, new parameters and alternative methodologies ab...

  9. Myocardial Perfusion Scintigraphy: Techniques, Interpretation, Indications and Reporting

    OpenAIRE

    Fathala, Ahmed

    2011-01-01

    Myocardial perfusion single photon emission-computed tomography (MPS) has been one of the most important and common non-invasive diagnostic cardiac test. Gated MPS provides simultaneous assessment of myocardial perfusion and function with only one study. With appropriate attention to the MPS techniques, appropriate clinical utilization and effective reporting, gated MPS will remain a useful diagnostic test for many years to come. The aim of this article is to review the basic techniques of MP...

  10. Diagnostic value of transmural perfusion ratio derived from dynamic CT-based myocardial perfusion imaging for the detection of haemodynamically relevant coronary artery stenosis

    NARCIS (Netherlands)

    A. Coenen (Adriaan); M. Lubbers (Marisa); A. Kurata (Akira); A.K. Kono (Atsushi K.); A. Dedic (Admir); R.G. Chelu (Raluca Gabriela); M.L. Dijkshoorn (Marcel); Rossi, A. (Alexia); R.J.M. van Geuns (Robert Jan); K. Nieman (Koen)

    2016-01-01

    textabstractObjectives: To investigate the additional value of transmural perfusion ratio (TPR) in dynamic CT myocardial perfusion imaging for detection of haemodynamically significant coronary artery disease compared with fractional flow reserve (FFR). Methods: Subjects with suspected or known coro

  11. CT Perfusion Characteristics Identify Metastatic Sites in Liver.

    Science.gov (United States)

    Wang, Yuan; Hobbs, Brian P; Ng, Chaan S

    2015-01-01

    Tissue perfusion plays a critical role in oncology because growth and migration of cancerous cells require proliferation of new blood vessels through the process of tumor angiogenesis. Computed tomography (CT) perfusion is an emerging functional imaging modality that measures tissue perfusion through dynamic CT scanning following intravenous administration of contrast medium. This noninvasive technique provides a quantitative basis for assessing tumor angiogenesis. CT perfusion has been utilized on a variety of organs including lung, prostate, liver, and brain, with promising results in cancer diagnosis, disease prognostication, prediction, and treatment monitoring. In this paper, we focus on assessing the extent to which CT perfusion characteristics can be used to discriminate liver metastases from neuroendocrine tumors from normal liver tissues. The neuroendocrine liver metastases were analyzed by distributed parameter modeling to yield tissue blood flow (BF), blood volume (BV), mean transit time (MTT), permeability (PS), and hepatic arterial fraction (HAF), for tumor and normal liver. The result reveals the potential of CT perfusion as a tool for constructing biomarkers from features of the hepatic vasculature for guiding cancer detection, prognostication, and treatment selection.

  12. CT Perfusion Characteristics Identify Metastatic Sites in Liver

    Directory of Open Access Journals (Sweden)

    Yuan Wang

    2015-01-01

    Full Text Available Tissue perfusion plays a critical role in oncology because growth and migration of cancerous cells require proliferation of new blood vessels through the process of tumor angiogenesis. Computed tomography (CT perfusion is an emerging functional imaging modality that measures tissue perfusion through dynamic CT scanning following intravenous administration of contrast medium. This noninvasive technique provides a quantitative basis for assessing tumor angiogenesis. CT perfusion has been utilized on a variety of organs including lung, prostate, liver, and brain, with promising results in cancer diagnosis, disease prognostication, prediction, and treatment monitoring. In this paper, we focus on assessing the extent to which CT perfusion characteristics can be used to discriminate liver metastases from neuroendocrine tumors from normal liver tissues. The neuroendocrine liver metastases were analyzed by distributed parameter modeling to yield tissue blood flow (BF, blood volume (BV, mean transit time (MTT, permeability (PS, and hepatic arterial fraction (HAF, for tumor and normal liver. The result reveals the potential of CT perfusion as a tool for constructing biomarkers from features of the hepatic vasculature for guiding cancer detection, prognostication, and treatment selection.

  13. Fast nonlinear regression method for CT brain perfusion analysis.

    Science.gov (United States)

    Bennink, Edwin; Oosterbroek, Jaap; Kudo, Kohsuke; Viergever, Max A; Velthuis, Birgitta K; de Jong, Hugo W A M

    2016-04-01

    Although computed tomography (CT) perfusion (CTP) imaging enables rapid diagnosis and prognosis of ischemic stroke, current CTP analysis methods have several shortcomings. We propose a fast nonlinear regression method with a box-shaped model (boxNLR) that has important advantages over the current state-of-the-art method, block-circulant singular value decomposition (bSVD). These advantages include improved robustness to attenuation curve truncation, extensibility, and unified estimation of perfusion parameters. The method is compared with bSVD and with a commercial SVD-based method. The three methods were quantitatively evaluated by means of a digital perfusion phantom, described by Kudo et al. and qualitatively with the aid of 50 clinical CTP scans. All three methods yielded high Pearson correlation coefficients ([Formula: see text]) with the ground truth in the phantom. The boxNLR perfusion maps of the clinical scans showed higher correlation with bSVD than the perfusion maps from the commercial method. Furthermore, it was shown that boxNLR estimates are robust to noise, truncation, and tracer delay. The proposed method provides a fast and reliable way of estimating perfusion parameters from CTP scans. This suggests it could be a viable alternative to current commercial and academic methods.

  14. Mucosal blood flow measurements using laser Doppler perfusion monitoring

    Institute of Scientific and Technical Information of China (English)

    Dag Arne Lihaug Hoff; Hans Gregersen; Jan Gunnar Hatlebakk

    2009-01-01

    Perfusion of individual tissues is a basic physiological process that is necessary to sustain oxygenation and nutrition at a cellular level. Ischemia, or the insufficiency of perfusion, is a common mechanism for tissue death or degeneration, and at a lower threshold, a mechanism for the generation of sensory signalling including pain. It is of considerable interest to study perfusion of peripheral abdominal tissues in a variety of circumstances. Microvascular disease of the abdominal organs has been implicated in the pathogenesis of a variety of disorders, including peptic ulcer disease, inflammatory bowel disease and chest pain. The basic principle of laser Doppler perfusion monitoring (LDPM) is to analyze changes in the spectrum of light reflected from tissues as a response to a beam of monochromatic laser light emitted. It reflects the total local microcirculatory blood perfusion, including perfusion in capillaries, arterioles, venules and shunts. During the last 20-25 years, numerous studies have been performed in different parts of the gastrointestinal (GI) tract using LDPM. In recent years we have developed a multi-modal catheter device which includes a laser Doppler probe, with the intent primarily to investigate patients suffering from functional chest pain of presumed oesophageal origin. Preliminary studies show the feasibility of incorporating LDPM into such catheters for performing physiological studies in the GI tract. LDPM has emerged as a research and clinical tool in preference to other methods; but, it is important to be aware of its limitations and account for them when reporting results.

  15. Perfusion-weighted MR imaging in persistent hemiplegic migraine

    Energy Technology Data Exchange (ETDEWEB)

    Mourand, Isabelle; Menjot de Champfleur, Nicolas; Carra-Dalliere, Clarisse; Le Bars, Emmanuelle; Bonafe, Alain; Thouvenot, Eric [Hopital Gui de Chauliac, Service de Neuroradiologie, Montpellier (France); Roubertie, Agathe [Hopital Gui de Chauliac, Service de Neuropediatrie, Montpellier (France)

    2012-03-15

    Hemiplegic migraine is a rare type of migraine that has an aura characterized by the presence of motor weakness, which may occasionally last up to several days, and then resolve without sequela. Pathogenesis of migraine remains unclear and, recently, perfusion-weighted imaging (PWI) has provided a non-invasive method to study hemodynamic changes during acute attacks. Two female patients were admitted in our hospital suffering from prolonged hemiparesis. In both cases, they underwent MRI examination using a 1.5 T magnet including axial diffusion-weighted and perfusion sequences. From each perfusion MRI acquisition two regions of interest were delineated on each hemisphere and, the index of flow, cerebral blood volume, mean transit time, and time to peak were recorded and asymmetry indices from each perfusion parameter were calculated. Perfusion alterations were detected during the attacks. In one case, we observed, after 3 h of left hemiparesia, hypoperfusion of the right hemisphere. In the other case, who presented a familial hemiplegic migraine attack, on the third day of a persistent aura consisting of right hemiplegia and aphasia, PWI revealed hyperperfusion of the left hemisphere. Asymmetry indices for temporal parameters (mean transit time and time to peak) were the most sensitive. These findings resolved spontaneously after the attacks without any permanent sequel or signs of cerebral ischemia on follow-up MRI. PWI should be indicated for patients with migraine attacks accompanied by auras to assess the sequential changes in cerebral perfusion and to better understand its pathogenesis. (orig.)

  16. k-t SENSE-accelerated Myocardial Perfusion MR Imaging at 3.0 Tesla - comparison with 1.5 Tesla

    Science.gov (United States)

    Plein, Sven; Schwitter, Juerg; Suerder, Daniel; Greenwood, John P.; Boesiger, Peter; Kozerke, Sebastian

    2008-01-01

    Purpose To determine the feasibility and diagnostic accuracy of high spatial resolution myocardial perfusion MR at 3.0 Tesla using k-space and time domain undersampling with sensitivity encoding (k-t SENSE). Materials and Methods The study was reviewed and approved by the local ethic review board. k-t SENSE perfusion MR was performed at 1.5 Tesla and 3.0 Tesla (saturation recovery gradient echo pulse sequence, repetition time/echo time 3.0ms/1.0ms, flip angle 15°, 5x k-t SENSE acceleration, spatial resolution 1.3×1.3×10mm3). Fourteen volunteers were studied at rest and 37 patients during adenosine stress. In volunteers, comparison was also made with standard-resolution (2.5×2.5×10mm3) 2x SENSE perfusion MR at 3.0 Tesla. Image quality, artifact scores, signal-to-noise ratios (SNR) and contrast-enhancement ratios (CER) were derived. In patients, diagnostic accuracy of visual analysis to detect >50% diameter stenosis on quantitative coronary angiography was determined by receiver-operator-characteristics (ROC). Results In volunteers, image quality and artifact scores were similar for 3.0 Tesla and 1.5 Tesla, while SNR was higher (11.6 vs. 5.6) and CER lower (1.1 vs. 1.5, p=0.012) at 3.0 Tesla. Compared with standard-resolution perfusion MR, image quality was higher for k-t SENSE (3.6 vs. 3.1, p=0.04), endocardial dark rim artifacts were reduced (artifact thickness 1.6mm vs. 2.4mm, pTesla and 1.5 Tesla, respectively. Conclusions k-t SENSE accelerated high-resolution perfusion MR at 3.0 Tesla is feasible with similar artifacts and diagnostic accuracy as at 1.5 Tesla. Compared with standard-resolution perfusion MR, image quality is improved and artifacts are reduced. PMID:18936311

  17. Integrating evidence-based perfusion into practices: the International Consortium for Evidence-Based Perfusion.

    Science.gov (United States)

    Likosky, Donald S

    2006-12-01

    There is surmounting pressure for clinicians domestically and abroad not only to practice evidence-based perfusion, but also to supplement practice with documentation thereof. In this editorial, I shall describe an international initiative aimed at embracing this dictum from patients, regulatory bodies, and payers. "Research is the only hope that the future will be different than the past"- Daniel Mintz, MD "Practical men who believe themselves to be quite exempt from any intellectual influences are usually the slaves of some defunct economist.... It is ideas not vested interests which are dangerous for good or evil."-John Maynard Keynes.

  18. Low dose dynamic CT myocardial perfusion imaging using a statistical iterative reconstruction method

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Yinghua [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States); Chen, Guang-Hong [Department of Medical Physics and Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States); Hacker, Timothy A.; Raval, Amish N. [Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53792 (United States); Van Lysel, Michael S.; Speidel, Michael A., E-mail: speidel@wisc.edu [Department of Medical Physics and Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States)

    2014-07-15

    Purpose: Dynamic CT myocardial perfusion imaging has the potential to provide both functional and anatomical information regarding coronary artery stenosis. However, radiation dose can be potentially high due to repeated scanning of the same region. The purpose of this study is to investigate the use of statistical iterative reconstruction to improve parametric maps of myocardial perfusion derived from a low tube current dynamic CT acquisition. Methods: Four pigs underwent high (500 mA) and low (25 mA) dose dynamic CT myocardial perfusion scans with and without coronary occlusion. To delineate the affected myocardial territory, an N-13 ammonia PET perfusion scan was performed for each animal in each occlusion state. Filtered backprojection (FBP) reconstruction was first applied to all CT data sets. Then, a statistical iterative reconstruction (SIR) method was applied to data sets acquired at low dose. Image voxel noise was matched between the low dose SIR and high dose FBP reconstructions. CT perfusion maps were compared among the low dose FBP, low dose SIR and high dose FBP reconstructions. Numerical simulations of a dynamic CT scan at high and low dose (20:1 ratio) were performed to quantitatively evaluate SIR and FBP performance in terms of flow map accuracy, precision, dose efficiency, and spatial resolution. Results: Forin vivo studies, the 500 mA FBP maps gave −88.4%, −96.0%, −76.7%, and −65.8% flow change in the occluded anterior region compared to the open-coronary scans (four animals). The percent changes in the 25 mA SIR maps were in good agreement, measuring −94.7%, −81.6%, −84.0%, and −72.2%. The 25 mA FBP maps gave unreliable flow measurements due to streaks caused by photon starvation (percent changes of +137.4%, +71.0%, −11.8%, and −3.5%). Agreement between 25 mA SIR and 500 mA FBP global flow was −9.7%, 8.8%, −3.1%, and 26.4%. The average variability of flow measurements in a nonoccluded region was 16.3%, 24.1%, and 937

  19. Chemosaturation Percutaneous Hepatic Perfusion: A Systematic Review.

    Science.gov (United States)

    Vogel, Arndt; Gupta, Sanjay; Zeile, Martin; von Haken, Rebecca; Brüning, Roland; Lotz, Gösta; Vahrmeijer, Alexander; Vogl, Thomas; Wacker, Frank

    2017-01-01

    The Hepatic CHEMOSAT(®) Delivery System is an innovative medical device for the treatment of patients with unresectable primary liver tumors or unresectable hepatic metastases from solid organ malignancies. This system is used to perform chemosaturation percutaneous hepatic perfusion (CS-PHP), a procedure in which a high dose of the chemotherapeutic agent melphalan is delivered directly to the liver while limiting systemic exposure. In a clinical trial program, CS-PHP with melphalan significantly improved hepatic progression-free survival in patients with unresectable hepatic metastases from ocular or cutaneous melanoma. Clinically meaningful hepatic responses were also observed in patients with hepatocellular carcinoma or neuroendocrine tumors. Furthermore, the results of published studies and case reports demonstrated that CS-PHP with melphalan resulted in favorable tumor response rates in a range of tumor histologies (ocular or cutaneous melanoma, colorectal cancer, and hepatobiliary tumors). Analyses of the safety profile of CS-PHP revealed that the most common adverse effects were hematologic events (thrombocytopenia, anemia, and neutropenia), which were clinically manageable. Taken together, these findings indicate that CS-PHP is a promising locoregional therapy for patients with primary and secondary liver tumors and has a acceptable safety profile.

  20. Serial investigation of perfusion disturbances and vasogenic oedema in hypertensive encephalopathy by diffusion and perfusion weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sundgren, P.C.; Holtaas, S. [Department of Diagnostic Radiology, University Hospital of Lund (Sweden); Edvardsson, B. [Department of Neurology, University Hospital of Lund (Sweden)

    2002-04-01

    Serial MRI including diffusion and perfusion imaging was performed in a patient with hypertensive encephalopathy. At admission, the patient was disorientated and presented with seizures and cortical blindness. Perfusion imaging showed a marked reduction in blood volume and flow, with corresponding vasogenic oedema in the occipital, posterior temporal, and, to a lesser extent, frontal lobes. The clinical symptoms disappeared rapidly following treatment, whereas the disturbed circulation pattern and vasogenic oedema resolved more slowly. A complete normalisation was seen after 1 year. (orig.)

  1. End-ischemic machine perfusion reduces bile duct injury in donation after circulatory death rat donor livers independent of the machine perfusion temperature

    NARCIS (Netherlands)

    Westerkamp, Andrie C.; Mahboub, Paria; Meyer, Sophie L.; Hottenrott, Maximilia; Ottens, Petra J.; Wiersma-Buist, Janneke; Gouw, Annette S. H.; Lisman, Ton; Leuvenink, Henri G. D.; Porte, Robert J.

    2015-01-01

    A short period of oxygenated machine perfusion (MP) after static cold storage (SCS) may reduce biliary injury in donation after cardiac death (DCD) donor livers. However, the ideal perfusion temperature for protection of the bile ducts is unknown. In this study, the optimal perfusion temperature for

  2. Color-Doppler sonographic tissue perfusion measurements reveal significantly diminished renal cortical perfusion in kidneys with vesicoureteral reflux.

    Science.gov (United States)

    Scholbach, T M; Sachse, C

    2016-01-01

    Vesicoureteral reflux (VUR) and its sequelae may lead to reduced renal perfusion and loss of renal function. Methods to describe and monitor tissue perfusion are needed. We investigated dynamic tissue perfusion measurement (DTPM) with the PixelFlux-software to measure microvascular changes in the renal cortex in 35 children with VUR and 28 healthy children. DTPM of defined horizontal slices of the renal cortex was carried out. A kidney was assigned to the "low grade reflux"-group if the reflux grade of the voiding cystourethrogram was 1 to 3 and to the "high grade reflux"-group if the reflux grade was 4 to 5. Kidneys with VUR showed a significantly reduced cortical perfusion. Compared to healthy kidneys, this decline reached in low and high grade refluxes within the proximal 50% of the cortex: 3% and 12 %, in the distal 50% of the cortex: 21% and 44 % and in the most distal 20 % of the cortex 41% and 44%. DTPM reveals a perfusion loss in kidneys depending on the degree of VUR, which is most pronounced in the peripheral cortex. Thus, DTPM offers the tool to evaluate microvascular perfusion, to help planning treatment decisions in children with VUR.

  3. Intraoperative imaging of cortical perfusion by time-resolved thermography using cold bolus approach

    Science.gov (United States)

    Hollmach, Julia; Schnabel, Christian; Hoffmann, Nico; Radev, Yordan; Sobottka, Stephan; Kirsch, Matthias; Schackert, Gabriele; Koch, Edmund; Steiner, Gerald

    2014-03-01

    During the past decade, thermographic cameras with high thermal and temporal resolution of up to 30 mK and 50 Hz, respectively, have been developed. These camera systems can be used to reveal thermal variations and heterogeneities of tissue and blood. Thus, they provide a fast, sensitive, noninvasive, and label-free application to investigate blood perfusion and to detect perfusion disorders. Therefore, time-resolved thermography is evaluated and tested for intraoperative imaging of the cerebral cortex during neurosurgeries. The motivation of this study is the intraoperative evaluation of the cortical perfusion by observing the temporal temperature curve of the cortex during and after the intravenous application of a cold bolus. The temperature curve caused by a cold bolus is influenced by thermodilution, depending on the temperature difference to the patient's circulation, and the pattern of mixing with the patient's blood. In this initial study, a flow phantom was used in order to determine the temperature variations of cold boli under stable conditions in a vascular system. The typical temperature profile of cold water passing by can be approximated by a bi- Gaussian function involving a set of four parameters. These parameters can be used to assess the cold bolus, since they provide information about its intensity, duration and arrival time. The findings of the flow phantom can be applied to thermographic measurements of the human cortex. The results demonstrate that time-resolved thermographic imaging is a suitable method to detect cold boli not only at a flow phantom but also at the human cortex.

  4. Quantitative myocardial perfusion PET parametric imaging at the voxel-level.

    Science.gov (United States)

    Mohy-Ud-Din, Hassan; Lodge, Martin A; Rahmim, Arman

    2015-08-01

    Quantitative myocardial perfusion (MP) PET has the potential to enhance detection of early stages of atherosclerosis or microvascular dysfunction, characterization of flow-limiting effects of coronary artery disease (CAD), and identification of balanced reduction of flow due to multivessel stenosis. We aim to enable quantitative MP-PET at the individual voxel level, which has the potential to allow enhanced visualization and quantification of myocardial blood flow (MBF) and flow reserve (MFR) as computed from uptake parametric images. This framework is especially challenging for the (82)Rb radiotracer. The short half-life enables fast serial imaging and high patient throughput; yet, the acquired dynamic PET images suffer from high noise-levels introducing large variability in uptake parametric images and, therefore, in the estimates of MBF and MFR. Robust estimation requires substantial post-smoothing of noisy data, degrading valuable functional information of physiological and pathological importance. We present a feasible and robust approach to generate parametric images at the voxel-level that substantially reduces noise without significant loss of spatial resolution. The proposed methodology, denoted physiological clustering, makes use of the functional similarity of voxels to penalize deviation of voxel kinetics from physiological partners. The results were validated using extensive simulations (with transmural and non-transmural perfusion defects) and clinical studies. Compared to post-smoothing, physiological clustering depicted enhanced quantitative noise versus bias performance as well as superior recovery of perfusion defects (as quantified by CNR) with minimal increase in bias. Overall, parametric images obtained from the proposed methodology were robust in the presence of high-noise levels as manifested in the voxel time-activity-curves.

  5. Dose reduction in dynamic perfusion CT of the brain: effects of the scan frequency on measurements of cerebral blood flow, cerebral blood volume, and mean transit time

    Energy Technology Data Exchange (ETDEWEB)

    Wiesmann, Martin [University of Munich, Department of Neuroradiology, Muenchen (Germany); Klinikum der Universitaet Muenchen - Grosshadern, Abteilung fuer Neuroradiologie, Muenchen (Germany); Berg, Scott; Stoeckelhuber, B.M. [University of Luebeck, Department of Radiology, Luebeck (Germany); Bohner, G.; Klingebiel, R. [University Medicine Berlin, Department of Neuroradiology, Charite, Berlin (Germany); Schoepf, V.; Yousry, I.; Linn, J. [University of Munich, Department of Neuroradiology, Muenchen (Germany); Missler, U. [Evangelisches Krankenhaus Duisburg-Nord, Department of Neuroradiology, Duisburg (Germany)

    2008-12-15

    The influence of the frequency of computed tomography (CT) image acquistion on the diagnostic quality of dynamic perfusion CT (PCT) studies of the brain was investigated. Eight patients with clinically suspected acute ischemia of one hemisphere underwent PCT, performed on average 3.4 h after the onset of symptoms. Sixty consecutive images per slice were obtained with individual CT images obtained at a temporal resolution of two images per second. Eight additional data sets were reconstructed with temporal resolutions ranging from one image per second to one image per 5 s. Cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) measurements were performed in identical regions of interest. Two neuroradiologists evaluated the PCT images visually to identify areas of abnormal perfusion. Perfusion images created up to a temporal resolution of one image per 3 s were rated to be diagnostically equal to the original data. Even at one image per 4 s, all areas of infarction were identified. Quantitative differences of CBF, CBV and MTT measurements were {<=}10% up to one image per 3 s. For PCT of the brain, temporal resolution can be reduced to one image per 3 s without significant compromise in image quality. This significantly reduces the radiation dose of the patient. (orig.)

  6. Single-energy computed tomography-based pulmonary perfusion imaging: Proof-of-principle in a canine model.

    Science.gov (United States)

    Yamamoto, Tokihiro; Kent, Michael S; Wisner, Erik R; Johnson, Lynelle R; Stern, Joshua A; Qi, Lihong; Fujita, Yukio; Boone, John M

    2016-07-01

    Radiotherapy (RT) that selectively avoids irradiating highly functional lung regions may reduce pulmonary toxicity, which is substantial in lung cancer RT. Single-energy computed tomography (CT) pulmonary perfusion imaging has several advantages (e.g., higher resolution) over other modalities and has great potential for widespread clinical implementation, particularly in RT. The purpose of this study was to establish proof-of-principle for single-energy CT perfusion imaging. Single-energy CT perfusion imaging is based on the following: (1) acquisition of end-inspiratory breath-hold CT scans before and after intravenous injection of iodinated contrast agents, (2) deformable image registration (DIR) for spatial mapping of those two CT image data sets, and (3) subtraction of the precontrast image data set from the postcontrast image data set, yielding a map of regional Hounsfield unit (HU) enhancement, a surrogate for regional perfusion. In a protocol approved by the institutional animal care and use committee, the authors acquired CT scans in the prone position for a total of 14 anesthetized canines (seven canines with normal lungs and seven canines with diseased lungs). The elastix algorithm was used for DIR. The accuracy of DIR was evaluated based on the target registration error (TRE) of 50 anatomic pulmonary landmarks per subject for 10 randomly selected subjects as well as on singularities (i.e., regions where the displacement vector field is not bijective). Prior to perfusion computation, HUs of the precontrast end-inspiratory image were corrected for variation in the lung inflation level between the precontrast and postcontrast end-inspiratory CT scans, using a model built from two additional precontrast CT scans at end-expiration and midinspiration. The authors also assessed spatial heterogeneity and gravitationally directed gradients of regional perfusion for normal lung subjects and diseased lung subjects using a two-sample two-tailed t-test. The mean TRE

  7. Unary resolution

    DEFF Research Database (Denmark)

    Aubert, Clément; Bagnol, Marc; Seiller, Thomas

    2016-01-01

    of the cut-elimination procedure of linear logic known as the geometry of interaction . This framework is restricted to terms (logic programs, rewriting rules) using only unary symbols, and this restriction is shown to be complete for polynomial time computation by encoding pushdown automata. Soundness w......We give a characterization of deterministic polynomial time computation based on an algebraic structure called the resolution semiring, whose elements can be understood as logic programs or sets of rewriting rules over first-order terms. This construction stems from an interactive interpretation...

  8. Management of Liver Cancer Argon-helium Knife Therapy with Functional Computer Tomography Perfusion Imaging.

    Science.gov (United States)

    Wang, Hongbo; Shu, Shengjie; Li, Jinping; Jiang, Huijie

    2016-02-01

    The objective of this study was to observe the change in blood perfusion of liver cancer following argon-helium knife treatment with functional computer tomography perfusion imaging. Twenty-seven patients with primary liver cancer treated with argon-helium knife and were included in this study. Plain computer tomography (CT) and computer tomography perfusion (CTP) imaging were conducted in all patients before and after treatment. Perfusion parameters including blood flows, blood volume, hepatic artery perfusion fraction, hepatic artery perfusion, and hepatic portal venous perfusion were used for evaluating therapeutic effect. All parameters in liver cancer were significantly decreased after argon-helium knife treatment (p liver tissue, but other parameters kept constant. CT perfusion imaging is able to detect decrease in blood perfusion of liver cancer post-argon-helium knife therapy. Therefore, CTP imaging would play an important role for liver cancer management followed argon-helium knife therapy.

  9. Diminishing the impact of the partial volume effect in cardiac SPECT perfusion imaging.

    Science.gov (United States)

    Pretorius, P Hendrik; King, Michael A

    2009-01-01

    The partial volume effect (PVE) significantly restricts the absolute quantification of regional myocardial uptake and thereby limits the accuracy of absolute measurement of blood flow and coronary flow reserve by SPECT. The template-projection-reconstruction method has been previously developed for PVE compensation. This method assumes the availability of coregistered high-spatial resolution anatomical information as is now becoming available with commercial dual-modality imaging systems such as SPECT/CTs. The objective of this investigation was to determine the extent to which the impact of the PVE on cardiac perfusion SPECT imaging can be diminished if coregistered high-spatial resolution anatomical information is available. For this investigation the authors introduced an additional parameter into the template-projection-reconstruction compensation equation called the voxel filling fraction (F). This parameter specifies the extent to which structure edge voxels in the emission reconstruction are filled by the structure in question as determined by the higher spatial-resolution imaging modality and the fractional presence of the structure at different states of physiological motion as in combining phases of cardiac motion. During correction the removal of spillover to the cardiac region from the surrounding structures is performed first by using reconstructed templates of neighboring structures (liver, blood pool, lungs) to calculate spillover fractions. This is followed by determining recovery coefficients for all voxels within the heart wall from the reconstruction of the template projections of the left and right ventricles (LV and RV). The emission data are subsequently divided by these recovery coefficients taking into account the filling fraction F. The mathematical cardiac torso phantom was used for investigation correction of PVE for a normal LV distribution, a defect in the inferior wall, and a defect in the anterior wall. PVE correction resulted in a

  10. Investigation on the optical scan condition for imaging of multi-slice spiral CT liver perfusion in rats

    Institute of Scientific and Technical Information of China (English)

    BAI Rong-jie; WANG Jin-e; JIANG Hui-jie; HAO Xue-jia; DONG Xu-peng; HUANG Ya-hua; WEI Lai

    2013-01-01

    Background Multi-slice CT liver perfusion has been widely used in experimental studies of hemodynamic changes in liver lesions,and is usually performed as an adjunct to a conventional CT examination because of its high temporal and spatial resolution,simple protocol,good reproducibility,and ability to measure hemodynamic changes of liver tissues at the capillary level.Experimental rat models,especially those of induced liver cancer,are often used in studies of hemodynamic changes in liver cancer.Carcinogenesis in rats has a similar pathological progression and characteristics resembling those in human liver cancer; as a result,rat models are often used as ideal animal models in the study of human liver cancer.However,liver perfusion imaging in rats is difficult to perform,because rats' livers are so small that different concentrations,flow rates,and dose of contrast agents during the CT perfusion scanning can influence the quality of liver perfusion images in rats.The purpose of this study,therefore,was to investigate the optimal scan protocol for the imaging of hepatic perfusion using a deconvolution mathematical method in rats by comparing the results of rats in different injection conditions of the contrast agent,including concentration,rate and time.Methods Plain CT scan conditions in eighty 2-month-old male Wistar rats were 5.0 mm slice thickness,5.0 mm interval,1.0 pitch,120 kV tube voltage,60 mA tube current,512×512 matrix,and FOV 9.6 cm.Perfusion scanning was carried out with different concentrations of diatrizoate (19%,38%,57%,and 76%),different injection rates (0.3 and 0.5 mi/s),and different injection times (1,2-3,4-5,and 6 seconds).The above conditions were randomly matched and adjusted to determine the best perfusion scan protocol.Thrae-phase contrast-enhanced scanning was performed after CT perfusion.Histological examination of the liver tissues with hematoxylin and eosin stains was done after CT scanning.Results When the concentration of the

  11. Perfusion imaging with non-contrast ultrasound

    Science.gov (United States)

    Tierney, Jaime E.; Dumont, Douglas M.; Byram, Brett C.

    2016-04-01

    A Doppler ultrasound clutter filter that enables estimation of low velocity blood flow could considerably improve ultrasound as a tool for clinical diagnosis and monitoring, including for the evaluation of vascular diseases and tumor perfusion. Conventional Doppler ultrasound is currently used for visualizing and estimating blood flow. However, conventional Doppler is limited by frame rate and tissue clutter caused by involuntary movement of the patient or sonographer. Spectral broadening of the clutter due to tissue motion limits ultrasound's ability to detect blood flow less than about 5mm/s at an 8MHz center frequency. We propose a clutter filtering technique that may increase the sensitivity of Doppler measurements to at least as low as 0.41mm/s. The proposed filter uses an adaptive demodulation scheme that decreases the bandwidth of the clutter. To test the performance of the adaptive demodulation method at removing sonographer hand motion, six volunteer subjects acquired data from a basic quality assurance phantom. Additionally, to test initial in vivo feasibility, an arterial occlusion reactive hyperemia study was performed to assess the efficiency of the proposed filter at preserving signals from blood velocities 2mm/s or greater. The hand motion study resulted in initial average bandwidths of 577Hz (28.5mm/s), which were decreased to 7.28Hz (0.36mm/s) at -60 dB at 3cm using our approach. The in vivo power Doppler study resulted in 15.2dB and 0.15dB dynamic ranges between the lowest and highest blood flow time points for the proposed filter and conventional 50Hz high pass filter, respectively.

  12. Adenosine stress protocols for myocardial perfusion imaging

    Directory of Open Access Journals (Sweden)

    Baškot Branislav

    2008-01-01

    Full Text Available Background/Aim. Treadmill test combined with myocardial perfusion scintigraphy (MPS is a commonly used technique in the assessment of coronary artery disease. There are many patients, however, who may not be able to undergo treadmill test. Such patients would benefit from pharmacological stress procedures combined with MPS. The most commonly used pharmacological agents for cardiac stress are coronary vasodilatators (adenosine, dipyridamol and catecholamines. Concomitant low-level treadmill exercise with adenosine pharmacologic stress (AdenoEX during MPS has become commonly used in recent years. A number of studies have demonstrated a beneficial impact of AdenoEX protocol. The aim of the study was, besides introducing into practice the two types of protocols of pharmatological stress test with adenosine, as a preparation for MPS, to compare and monitor the frequency of their side effects to quality, acquisition, as well as to standardize the onset time of acquisition (diagnostic imaging for both protocols. Methods. A total of 130 patients underwent pharmacological stress test with adenosine (vasodilatator. In 108 of the patients we performed concomitant exercise (AdenoEX of low level (50W by a bicycle ergometar. In 28 of the patients we performed Adenosine abbreviated protocol (AdenoSCAN. Side effects of adenosine were followed and compared between the two kinds of protocols AdenoEX and AdenoSCAN. Also compared were image quality and suggested time of acquisition after the stress test. Results. Numerous side effects were found, but being short-lived they did not require any active interventions. The benefit of AdenoEX versus AdenoSCAN included decreased side effects (62% vs 87%, improved safety and patients tolerance, improved target-to-background ratios because of less subdiaphragmatic activity, earlier acquisition, and improved sensitivity. Conclusion. The safety and efficacy of adenosine pharmacological stress is even better with concomitant

  13. Investigation of optimal acquisition time of myocardial perfusion scintigraphy using cardiac focusing-collimator

    Science.gov (United States)

    Niwa, Arisa; Abe, Shinji; Fujita, Naotoshi; Kono, Hidetaka; Odagawa, Tetsuro; Fujita, Yusuke; Tsuchiya, Saki; Kato, Katsuhiko

    2015-03-01

    Recently myocardial perfusion SPECT imaging acquired using the cardiac focusing-collimator (CF) has been developed in the field of nuclear cardiology. Previously we have investigated the basic characteristics of CF using physical phantoms. This study was aimed at determining the acquisition time for CF that enables to acquire the SPECT images equivalent to those acquired by the conventional method in 201TlCl myocardial perfusion SPECT. In this study, Siemens Symbia T6 was used by setting the torso phantom equipped with the cardiac, pulmonary, and hepatic components. 201TlCl solution were filled in the left ventricular (LV) myocardium and liver. Each of CF, the low energy high resolution collimator (LEHR), and the low medium energy general purpose collimator (LMEGP) was set on the SPECT equipment. Data acquisitions were made by regarding the center of the phantom as the center of the heart in CF at various acquisition times. Acquired data were reconstructed, and the polar maps were created from the reconstructed images. Coefficient of variation (CV) was calculated as the mean counts determined on the polar maps with their standard deviations. When CF was used, CV was lower at longer acquisition times. CV calculated from the polar maps acquired using CF at 2.83 min of acquisition time was equivalent to CV calculated from those acquired using LEHR in a 180°acquisition range at 20 min of acquisition time.

  14. An arterially perfused nose-olfactory bulb preparation of the rat.

    Science.gov (United States)

    Pérez de los Cobos Pallarés, Fernando; Stanić, Davor; Farmer, David; Dutschmann, Mathias; Egger, Veronica

    2015-09-01

    A main feature of the mammalian olfactory bulb network is the presence of various rhythmic activities, in particular, gamma, beta, and theta oscillations, with the latter coupled to the respiratory rhythm. Interactions between those oscillations as well as the spatial distribution of network activation are likely to determine olfactory coding. Here, we describe a novel semi-intact perfused nose-olfactory bulb-brain stem preparation in rats with both a preserved olfactory epithelium and brain stem, which could be particularly suitable for the study of oscillatory activity and spatial odor mapping within the olfactory bulb, in particular, in hitherto inaccessible locations. In the perfused olfactory bulb, we observed robust spontaneous oscillations, mostly in the theta range. Odor application resulted in an increase in oscillatory power in higher frequency ranges, stimulus-locked local field potentials, and excitation or inhibition of individual bulbar neurons, similar to odor responses reported from in vivo recordings. Thus our method constitutes the first viable in situ preparation of a mammalian system that uses airborne odor stimuli and preserves these characteristic features of odor processing. This preparation will allow the use of highly invasive experimental procedures and the application of techniques such as patch-clamp recording, high-resolution imaging, and optogenetics within the entire olfactory bulb.

  15. Circular tomosynthesis for neuro perfusion imaging on an interventional C-arm

    Science.gov (United States)

    Claus, Bernhard E.; Langan, David A.; Al Assad, Omar; Wang, Xin

    2015-03-01

    There is a clinical need to improve cerebral perfusion assessment during the treatment of ischemic stroke in the interventional suite. The clinician is able to determine whether the arterial blockage was successfully opened but is unable to sufficiently assess blood flow through the parenchyma. C-arm spin acquisitions can image the cerebral blood volume (CBV) but are challenged to capture the temporal dynamics of the iodinated contrast bolus, which is required to derive, e.g., cerebral blood flow (CBF) and mean transit time (MTT). Here we propose to utilize a circular tomosynthesis acquisition on the C-arm to achieve the necessary temporal sampling of the volume at the cost of incomplete data. We address the incomplete data problem by using tools from compressed sensing and incorporate temporal interpolation to improve our temporal resolution. A CT neuro perfusion data set is utilized for generating a dynamic (4D) volumetric model from which simulated tomo projections are generated. The 4D model is also used as a ground truth reference for performance evaluation. The performance that may be achieved with the tomo acquisition and 4D reconstruction (under simulation conditions, i.e., without considering data fidelity limitations due to imaging physics and imaging chain) is evaluated. In the considered scenario, good agreement between the ground truth and the tomo reconstruction in the parenchyma was achieved.

  16. Initial experience in perfusion MR imaging of intracranial major artery occlusion with echo-planar technique

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, Kazuhiro; Mizutani, Yoshiyuki; Inaoka, Sayuki; Hachiya, Junichi [Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine

    1997-09-01

    The purpose of this study was to evaluate the usefulness of perfusion MR imaging using a single-shot echo-planar technique in occlusion of intracranial main arteries. Our patient group consisted of 16 patients with internal carotid artery occlusion (n=9), Moyamoya disease (n=4), and middle cerebral artery occlusion (n=3). We performed the echo-planar perfusion studies with a 1.5-T unit using a free-induction-decay-type echo-planar sequence. With a bolus injection of Gd-DTPA, 30 consecutive scans were obtained at 10 sections every 2 seconds. The data were analyzed in three ways: a time-intensity curves in the territory of the involved artery (n=16); semiquantitative flow map of each section representing signal changes due to passage of Gd-DTPA (n=15); and serial images at a selected section (n=7). The time intensity curves were abnormal in 13 patients. The peak of signal drop was delayed in all of them. Flow maps showed focal flow abnormalities in 11 patients, but they were apparently normal in 4 patients probably due to collateral flow. In serial images, delay in appearance and/or disappearance of Gd-DTPA was noted in 6 patients. In patients with occlusion of intracranial main arteries, MR single-shot echo-planar technique is of clinical use because it can provide information about hemodynamic changes in a short examination time, in multiple sections, and with good temporal resolution. (author)

  17. Gap Resolution

    Energy Technology Data Exchange (ETDEWEB)

    2017-04-25

    Gap Resolution is a software package that was developed to improve Newbler genome assemblies by automating the closure of sequence gaps caused by repetitive regions in the DNA. This is done by performing the follow steps:1) Identify and distribute the data for each gap in sub-projects. 2) Assemble the data associated with each sub-project using a secondary assembler, such as Newbler or PGA. 3) Determine if any gaps are closed after reassembly, and either design fakes (consensus of closed gap) for those that closed or lab experiments for those that require additional data. The software requires as input a genome assembly produce by the Newbler assembler provided by Roche and 454 data containing paired-end reads.

  18. Collimator optimization in myocardial perfusion SPECT using the ideal observer and realistic background variability for lesion detection and joint detection and localization tasks

    Science.gov (United States)

    Ghaly, Michael; Du, Yong; Links, Jonathan M.; Frey, Eric C.

    2016-03-01

    In SPECT imaging, collimators are a major factor limiting image quality and largely determine the noise and resolution of SPECT images. In this paper, we seek the collimator with the optimal tradeoff between image noise and resolution with respect to performance on two tasks related to myocardial perfusion SPECT: perfusion defect detection and joint detection and localization. We used the Ideal Observer (IO) operating on realistic background-known-statistically (BKS) and signal-known-exactly (SKE) data. The areas under the receiver operating characteristic (ROC) and localization ROC (LROC) curves (AUCd, AUCd+l), respectively, were used as the figures of merit for both tasks. We used a previously developed population of 54 phantoms based on the eXtended Cardiac Torso Phantom (XCAT) that included variations in gender, body size, heart size and subcutaneous adipose tissue level. For each phantom, organ uptakes were varied randomly based on distributions observed in patient data. We simulated perfusion defects at six different locations with extents and severities of 10% and 25%, respectively, which represented challenging but clinically relevant defects. The extent and severity are, respectively, the perfusion defect’s fraction of the myocardial volume and reduction of uptake relative to the normal myocardium. Projection data were generated using an analytical projector that modeled attenuation, scatter, and collimator-detector response effects, a 9% energy resolution at 140 keV, and a 4 mm full-width at half maximum (FWHM) intrinsic spatial resolution. We investigated a family of eight parallel-hole collimators that spanned a large range of sensitivity-resolution tradeoffs. For each collimator and defect location, the IO test statistics were computed using a Markov Chain Monte Carlo (MCMC) method for an ensemble of 540 pairs of defect-present and -absent images that included the aforementioned anatomical and uptake variability. Sets of test statistics were

  19. Effect of x-ray tube current on the accuracy of cerebral perfusion parameters obtained by CT perfusion studies

    Science.gov (United States)

    Murase, Kenya; Nanjo, Takafumi; Satoshi, Ii; Miyazaki, Shohei; Hirata, Masaaki; Sugawara, Yoshifumi; Kudo, Masayuki; Sasaki, Kousuke; Mochizuki, Teruhito

    2005-11-01

    The purpose of this study was to investigate the effect of x-ray tube current on the accuracy of cerebral perfusion parameters obtained by CT perfusion studies using multi-detector row CT (MDCT). Following the standard CT perfusion study protocol, continuous (cine) scans (1 s/rotation × 60 s) consisting of four 5 mm thick contiguous slices were performed using an MDCT scanner with a tube voltage of 80 kVp and a tube current of 200 mA. We generated the simulated images with tube currents of 50 mA, 100 mA and 150 mA by adding the corresponding noise to the raw scan data of the original image acquired above using a noise simulation tool. From the original and simulated images, we generated the functional images of cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) in seven patients with cerebrovascular disease, and compared the correlation coefficients (CCs) between the perfusion parameter values obtained from the original and simulated images. The coefficients of variation (CVs) in the white matter were also compared. The CC values deteriorated with decreasing tube current. There was a significant difference between 50 mA and 100 mA for all perfusion parameters. The CV values increased with decreasing tube current. There were significant differences between 50 mA and 100 mA and between 100 mA and 150 mA for CBF. For CBV and MTT, there was also a significant difference between 150 mA and 200 mA. This study will be useful for understanding the effect of x-ray tube current on the accuracy of cerebral perfusion parameters obtained by CT perfusion studies using MDCT, and for selecting the tube current.

  20. 99mTc sestamibi myocardial perfusion scintigraphy with the novel use of metamizol for the detection of perfusion reversibility.

    Science.gov (United States)

    Ergün, Eser Lay; Caglar, Meltem; Bozkurt, Murat Fani; Ergün, Hakan

    2008-08-01

    This study aims to investigate whether induction with metamizol, an analgesic-antipyretic drug having spasmolitic activity, could be used to increase the detectability of ischemic/jeopardized myocardium during MPS (myocardial perfusion scintigraphy). Metamizol-enhanced rest MPS (45 min after administration of 1 g metamizol orally, 740 MBq (99m)Tc sestamibi was injected, MPS was acquired 45 min later) was performed in 21 patients who had perfusion defects on their previous stress-rest (99m)Tc sestamibi MPS. Blood pressure was monitored at 15-min intervals. Stress, rest, metamizol-rest MPS images were interpreted on the model of 20 segments using a visual uptake score (VUS; 0 = normal, 1 = mild, 2 = moderate, 3 = significant decreases, 4 = no uptake). (99m)Tc sestamibi uptake ratios (MIBI-UR; mean counts in the region of the perfusion defect/mean counts in the region of the normal-perfused wall) were obtained on each MPS and compared with each other. Average MIBI-UR in each scintigraphic examination was calculated. MPS were compared with coronary angiography results. VUS and MIBI-UR results showed that metamizol-rest MPS displayed the defect reversibility better than rest MPS. Of the 14 segments with fixed perfusion defects on stress-rest MPS, 8 showed improvement of perfusion after metamizol induction. In 33 segments, lesion reversibility was better delineated on metamizol-rest MPS. Metamizol-induced sestamibi uptake was significantly higher (p metamizol induced MPS. Metamizol-enhanced rest MPS increases detectability of ischemic/viable myocardium during MPS. Metamizol should be discontinued like nitrates before stress MPS since it may mask the visualization of ischemic perfusion defects.

  1. Regional time-density measurement of myocardial perfusion

    Science.gov (United States)

    Eusemann, Christian D.; Breen, Jerome F.; Robb, Richard A.

    2003-05-01

    The measurement of time-density relationships of the myocardium in studies of Magnetic Resonance perfusion data sets is a clinical technique used in assessing myocardial perfusion. Traditionally, to measure the time-density relationship a physician draws a region on the same 2-D image of the myocardium in sequential cardiac cycles. Throughout multiple cardiac cycles the density changes in this region are measured. A major limitation of this technique is change in anatomy relative to the selected region on the myocardium during consecutive cardiac cycles. This causes measurement errors, which are amplified if the traced region does not encompass the entire myocardial thickness, or includes a boundary exterior to the epicardial or endocardial surface. The technique described in this paper uses approximately the same myocardial region throughout the entire perfusion study, which insures inclusion of the entire endocardial to epicardial region and exclusion of exterior regions. Moreover, this region can be subdivided into smaller regions of interest. This can be accomplished by careful segmentation and reformatting of the data into polar coordinates. This allows sectioning both axially and transaxially through the myocardium permitting regional assessment of perfusion specific values such as maximum and/or the time to reach maximum density. These values can then be illustrated using density-mapped colors or time-density curves. This measurement and display technique may provide enhanced detection and evaluation of regional deficits in myocardial contractility and perfusion.

  2. Perfusion calorimetry in the characterization of solvates forming isomorphic desolvates.

    Science.gov (United States)

    Baronsky, Julia; Preu, Martina; Traeubel, Michael; Urbanetz, Nora Anne

    2011-09-18

    In this study, the potential of perfusion calorimetry in the characterization of solvates forming isomorphic desolvates was investigated. Perfusion calorimetry was used to expose different hydrates forming isomorphic desolvates (emodepside hydrates II-IV, erythromycin A dihydrate and spirapril hydrochloride monohydrate) to stepwise increasing relative vapour pressures (RVP) of water and methanol, respectively, while measuring thermal activity. Furthermore, the suitability of perfusion calorimetry to distinguish the transformation of a desolvate into an isomorphic solvate from the adsorption of solvent molecules to crystal surfaces as well as from solvate formation that is accompanied by structural rearrangement was investigated. Changes in the samples were confirmed using FT-Raman and FT-IR spectroscopy. Perfusion calorimetry indicates the transformation of a desolvate into an isomorphic solvate by a substantial exothermic, peak-shaped heat flow curve at low RVP which reflects the rapid incorporation of solvent molecules by the desolvate to fill the structural voids in the lattice. In contrast, adsorption of solvent molecules to crystal surfaces is associated with distinctly smaller heat changes whereas solvate formation accompanied by structural changes is characterized by an elongated heat flow. Hence, perfusion calorimetry is a valuable tool in the characterization of solvates forming isomorphic desolvates which represents a new field of application for the method.

  3. Ventilation perfusion radionuclide imaging in cryptogenic fibrosing alveolitis

    Energy Technology Data Exchange (ETDEWEB)

    Bourke, S.J.; Hawkins, T.; Keavey, P.M.; Gascoigne, A.D.; Corris, P.A. (Freeman Hospital, Newcastle upon Tyne (United Kingdom))

    1993-06-01

    There is increasing interest in ventilation perfusion (V/Q) imaging in cryptogenic fibrosing alveolitis because of the data these scans provide on the dynamic V/Q relationships in such patients undergoing single lung transplantation. We analysed the V/Q scans of 45 consecutive patients with advanced cryptogenic fibrosing alveolitis being considered for single lung transplantation. Scans were classified according to the presence, severity and degree of matching of defects in ventilation and perfusion images and the results were compared with the data obtained from lung function tests. Ventilation images showed defects in 13 (29%) and ''washout delay'' in 15 (33%) patients; 10 (22%) patients had asymmetric distribution of ventilation with one lung receiving >60% of total ventilation. Perfusion images showed normal perfusion in 8 (18%), mild defects in 18 (40%) and major defects in 19 (42%) patients. The distribution of perfusion between lungs was significantly asymmetric in 20 (45%) patients. V/Q images were matched in 15 (33%), mildly mismatched in 15 (33%) and severely mismatched in 15 (33%) patients, but the degree of V/Q mismatch did not show a relationship to KCO, PaO[sub 2] or A-aO[sub 2] gradient. The appearances were atypical of pulmonary embolism in eight patients. (Author).

  4. Effect of vibration on muscle perfusion: a systematic review.

    Science.gov (United States)

    Fuller, Joel T; Thomson, Rebecca L; Howe, Peter R C; Buckley, Jonathan D

    2013-01-01

    Vibration has become of increasing interest to health professionals, primarily owing to reports that vibration can increase tissue blood flow. The aim of this review was to investigate the available scientific evidence on the effects of exogenous vibration on skeletal muscle perfusion. The databases searched from inception to December 2010 included Ovid MEDLINE, EMBASE, CINAHL via EbscoHost and CENTRAL. Experimental and observational studies, where exogenous vibration was an intervention, were included in this review. The main outcomes of interest were muscle blood volume, blood flow, blood flow velocity, arterial diameter and muscle temperature. One reviewer selected studies for inclusion, extracted data and assessed the quality of the eligible studies. Percentage change in muscle perfusion outcome was the measure of treatment effect, and regression analysis was used to investigate associations between vibratory load and muscle perfusion. Twenty-two studies with a total of 302 participants were included in this review. Muscle blood volume increased with vibration in five of nine studies and decreased in two studies; muscle blood flow velocity increased with vibration in five of six studies; muscle blood flow increased with vibration in two of three studies; vibration had a positive effect on arterial diameter in three of three studies; vibration had no effect on muscle temperature in two of two studies. The magnitude of increase in muscle perfusion was positively associated with vibratory load (Pvibration increases muscle perfusion with the magnitude of increase positively related to the vibratory load applied.

  5. Isolated Pelvic Hyperthermochemotherapeutic Perfusion -An Experimental Study on Isolating Efficacy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Hyperthermochemotherapeutic perfusion model through isolated pelvic vessels was developed to evaluate the leakage of hyperthermia and drugs (such as adriamycin) from the isolated pelvic circulation to systemic circulation and its associated side/toxic effects. The isolated pelvic circulation was perfused through a femoral artery catheter with hyperthermic (48 ℃ to 55 ℃) adriamycin solution (50 μg/ml) for 30 min. The efflux was drained through a femoral vein catheter. And the pelvic temperature was kept at the level of 43±0.5 ℃. The temperature of pelvic circulation was kept at 4 ℃ to 5 ℃ greater than the systemic/core temperature. The adriamycin concentration of pelvic efflux was 12 to 46 folds of that of systemic serum. The difference between them was very significant (P<0.001). As the perfusion pressure was increased, which kept lower than the mean systemic artery pressure, the leakage of the adriamycin from the isolated pelvic circulation to systemic circulation was increased, but there was no significant difference between them (P>0.05). During isolated perfusion, the systemic blood dynamics remained stable and there were no organic injuries on the important organs. It was suggested that the isolating efficacy of the modality of isolated pelvic hyperthermochemotherapeutic perfusion through vessels was rather high. The hyperthermia and drugs could be effectively limited in the isolated pelvic region with minor side effects on the systemic circulation and important organs.

  6. Job analysis and student assessment tool: perfusion education clinical preceptor.

    Science.gov (United States)

    Riley, Jeffrey B

    2007-09-01

    The perfusion education system centers on the cardiac surgery operating room and the perfusionist teacher who serves as a preceptor for the perfusion student. One method to improve the quality of perfusion education is to create a valid method for perfusion students to give feedback to clinical teachers. The preceptor job analysis consisted of a literature review and interviews with preceptors to list their critical tasks, critical incidents, and cognitive and behavioral competencies. Behaviorally anchored rating traits associated with the preceptors' tasks were identified. Students voted to validate the instrument items. The perfusion instructor rating instrument with a 0-4, "very weak" to "very strong" Likert rating scale was used. The five preceptor traits for student evaluation of clinical instruction (SECI) are as follows: The clinical instructor (1) encourages self-learning, (2) encourages clinical reasoning, (3) meets student's learning needs, (4) gives continuous feedback, and (5) represents a good role model. Scores from 430 student-preceptor relationships for 28 students rotating at 24 affiliate institutions with 134 clinical instructors were evaluated. The mean overall good preceptor average (GPA) was 3.45 +/- 0.76 and was skewed to the left, ranging from 0.0 to 4.0 (median = 3.8). Only 21 of the SECI relationships earned a GPA education program.

  7. Brain perfusion asymmetry in patients with oral somatic delusions.

    Science.gov (United States)

    Umezaki, Yojiro; Katagiri, Ayano; Watanabe, Motoko; Takenoshita, Miho; Sakuma, Tomomi; Sako, Emi; Sato, Yusuke; Toriihara, Akira; Uezato, Akihito; Shibuya, Hitoshi; Nishikawa, Toru; Motomura, Haruhiko; Toyofuku, Akira

    2013-06-01

    Oral cenesthopathy is a somatic delusion or hallucination involving the oral area and is categorized as a delusional disorder, somatic type. The pathophysiology of this intractable condition remains obscure. In this study, we clarified the pathophysiology of oral cenesthopathy by evaluating regional brain perfusion. We performed single photon emission computed tomography (SPECT) using (99m)Tc-ethylcysteinate dimer in 16 subjects (cenesthopathy:control = 8:8). The SPECT images were visually assessed qualitatively, and quantitative analyses were also performed using a three-dimensional stereotactic region-of-interest template. The visual assessment revealed a right > left perfusion asymmetry in broad areas of the brain among the patients. The quantitative analysis confirmed that the regional cerebral blood flow values on the right side were significantly larger than those on the left side for most areas of the brain in the patients. A comparison of the R/(R + L) ratios in both groups confirmed the significant brain perfusion asymmetry between the two sides in the callosomarginal, precentral, and temporal regions in the patients. Qualitative evaluation of the SPECT images revealed right > left brain perfusion asymmetry in broad regions of the brain. Moreover, the quantitative analyses confirmed the perfusion asymmetry between the two sides in the frontal and temporal areas. Those may provide the key for elucidation of the pathophysiology of oral cenesthopathy.

  8. Perfusion imaging with computed tomography: brain and beyond

    Energy Technology Data Exchange (ETDEWEB)

    Miles, K.A. [Div. of Clinical and Lab. Investigation, Brighton and Sussex Medical School, Univ. of Sussex, Falmer, Brighton (United Kingdom)

    2006-01-10

    The availability of rapid imaging with multidetector CT systems and commercial analysis software has made perfusion imaging with CT an everyday technique, not only for the brain but also for other body organs. Perfusion imaging is usually performed as an adjunct to a conventional CT examination and is therefore particularly appropriate when a conventional CT is part of routine clinical protocols. The derived values are reproducible and have been validated against a range of reference techniques. Within neuroradiology, perfusion CT has attracted interest in the assessment of acute stroke but can also be used to assess secondary injury in head trauma and as an adjunct to CT angiography to evaluate cerebral spasm in subarachnoid haemorrhage. Within oncology, perfusion CT provides an imaging correlate for tumour vascularity that can be used to discriminate benign and malignant lesions, as an indicator of tumour aggressiveness, to reveal occult tumour and improve the delineation of tumours during radiotherapy planning, and as a functional assessment of tumour response to therapy. By exploiting the ability of CT systems to quantify contrast enhancement. CT perfusion imaging uses contrast media to assess vascular physiology and so improve diagnosis, prognosis, treatment selection and therapy monitoring. (orig.)

  9. Usefulness of CT perfusion imaging in adult moyamoya disease

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Bo Bae; Kim, Young Joo; Song, Ha Hun; Kim, Ki Tae [College of Medicine, The Catholic University of Korea, Uijongbu (Korea, Republic of)

    2004-12-01

    The purpose of this study was to evaluate the role of perfusion CT in adult moyamoya disease. The study population consisted of 13 adult moyamoya patients (10 women and 3 men, mean age: 40.4 years) and 11 age-matched normal controls (5 men and 6 women, mean age: 43 years). We retrospectively assessed the perfusion CT scan both visually and by a quantitative regional analysis, and we assessed the relationship between the perfusion CT scan findings and the angiographic findings. The mean relative cerebral blood volume (rCBV) values in moyamoya patients were 8.0% for the MCA area, 6.4% for the PCA area, and 7.7% for the basal ganglia. The rCBV values in the patients were higher than those in the control group with statistical significance (p<0.0001). The time to peak enhancement (TTP) values of the MCA area and the basal ganglia were delayed more than those in the controls; this was statistically significant (p<0.05). Moderate correlation was found between the rCBV in the basal ganglia area and angiographic stage of the basal moyamoya vessels. Perfusion CT demonstrates a statisticaIly significant increase in rCBV in the MCA, PCA and basal ganglia areas and the TTP in the MCA and basal ganglia areas in patients with moyamoya disease. The visual brain perfusion patterns correIate with the extent and severity of the basal moyamoya vessels.

  10. Modelling of temperature and perfusion during scalp cooling

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, F E M; Leeuwen, G M J van; Steenhoven, A A van [Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)

    2005-09-07

    Hair loss is a feared side effect of chemotherapy treatment. It may be prevented by cooling the scalp during administration of cytostatics. The supposed mechanism is that by cooling the scalp, both temperature and perfusion are diminished, affecting drug supply and drug uptake in the hair follicle. However, the effect of scalp cooling varies strongly. To gain more insight into the effect of cooling, a computer model has been developed that describes heat transfer in the human head during scalp cooling. Of main interest in this study are the mutual influences of scalp temperature and perfusion during cooling. Results of the standard head model show that the temperature of the scalp skin is reduced from 34.4 deg. C to 18.3 deg. C, reducing tissue blood flow to 25%. Based upon variations in both thermal properties and head anatomies found in the literature, a parameter study was performed. The results of this parameter study show that the most important parameters affecting both temperature and perfusion are the perfusion coefficient Q{sub 10} and the thermal resistances of both the fat and the hair layer. The variations in the parameter study led to skin temperature ranging from 10.1 deg. C to 21.8 deg. C, which in turn reduced relative perfusion to 13% and 33%, respectively.

  11. Modelling of temperature and perfusion during scalp cooling

    Science.gov (United States)

    Janssen, F. E. M.; Van Leeuwen, G. M. J.; Van Steenhoven, A. A.

    2005-09-01

    Hair loss is a feared side effect of chemotherapy treatment. It may be prevented by cooling the scalp during administration of cytostatics. The supposed mechanism is that by cooling the scalp, both temperature and perfusion are diminished, affecting drug supply and drug uptake in the hair follicle. However, the effect of scalp cooling varies strongly. To gain more insight into the effect of cooling, a computer model has been developed that describes heat transfer in the human head during scalp cooling. Of main interest in this study are the mutual influences of scalp temperature and perfusion during cooling. Results of the standard head model show that the temperature of the scalp skin is reduced from 34.4 °C to 18.3 °C, reducing tissue blood flow to 25%. Based upon variations in both thermal properties and head anatomies found in the literature, a parameter study was performed. The results of this parameter study show that the most important parameters affecting both temperature and perfusion are the perfusion coefficient Q10 and the thermal resistances of both the fat and the hair layer. The variations in the parameter study led to skin temperature ranging from 10.1 °C to 21.8 °C, which in turn reduced relative perfusion to 13% and 33%, respectively.

  12. Numerical simulation of blood flow in femoral perfusion: comparison between side-armed femoral artery perfusion and direct femoral artery perfusion.

    Science.gov (United States)

    Kitamura, Shingo; Shirota, Minori; Fukuda, Wakako; Inamura, Takao; Fukuda, Ikuo

    2016-12-01

    Computational numerical analysis was performed to elucidate the flow dynamics of femoral artery perfusion. Numerical simulation of blood flow was performed from the right femoral artery in an aortic model. An incompressible Navier-Stokes equation and continuity equation were solved using computed flow dynamics software. Three different perfusion models were analyzed: a 4.0-mm cannula (outer diameter 15 French size), a 5.2-mm cannula (18 French size) and an 8-mm prosthetic graft. The cannula was inserted parallel to the femoral artery, while the graft was anastomosed perpendicular to the femoral artery. Shear stress was highest with the 4-mm cannula (172 Pa) followed by the graft (127 Pa) and the 5.2-mm cannula (99 Pa). The cannula exit velocity was high, even when the 5.2-mm cannula was used. Although side-armed perfusion with an 8-mm graft generated a high shear stress area near the point of anastomosis, flow velocity at the external iliac artery was decreased. The jet speed decreased due to the Coanda effect caused by the recirculation behind sudden expansion of diameter, and the flow velocity maintains a constant speed after the reattachment length of the flow. This study showed that iliac artery shear stress was lower with the 5.2-mm cannula than with the 4-mm cannula when used for femoral perfusion. Side-armed graft perfusion generates a high shear stress area around the anastomotic site, but flow velocity in the iliac artery is slower in the graft model than in the 5.2-mm cannula model.

  13. Relationship between diffusion parameters derived from intravoxel incoherent motion MRI and perfusion measured by dynamic contrast-enhanced MRI of soft tissue tumors.

    Science.gov (United States)

    Marzi, Simona; Stefanetti, Linda; Sperati, Francesca; Anelli, Vincenzo

    2016-01-01

    Our aim was to evaluate the link between diffusion parameters measured by intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) and the perfusion metrics obtained with dynamic contrast-enhanced (DCE) MRI in soft tissue tumors (STTs). Twenty-eight patients affected by histopathologically confirmed STT were included in a prospective study. All patients underwent both DCE MRI and IVIM DWI. The perfusion fraction f, diffusion coefficient D and perfusion-related diffusion coefficient D* were estimated using a bi-exponential function to fit the DWI data. DCE MRI was acquired with a temporal resolution of 3-5 s. Maps of the initial area under the gadolinium concentration curve (IAUGC), time to peak (TTP) and maximum slope of increase (MSI) were derived using commercial software. The relationships between the DCE MRI and IVIM DWI measurements were assessed by Spearman's test. To exclude false positive results under multiple testing, the false discovery rate (FDR) procedure was applied. The Mann-Whitney test was used to evaluate the differences between all variables in patients with non-myxoid and myxoid STT. No significant relationship was found between IVIM parameters and any DCE MRI parameters. Higher f and D*f values were found in non-myxoid tumors compared with myxoid tumors (p = 0.004 and p = 0.003, respectively). MSI was significantly higher in non-myxoid tumors than in myxoid tumors (p = 0.029). From the visual assessments of single clinical cases, both f and D*f maps were in satisfactory agreement with DCE maps in the extreme cases of an avascular mass and a highly vascularized mass, whereas, for tumors with slight vascularity or with a highly heterogeneous perfusion pattern, this association was not straightforward. Although IVIM DWI was demonstrated to be feasible in STT, our data did not support evident relationships between perfusion-related IVIM parameters and perfusion measured by DCE MRI.

  14. Mapping the dynamics of brain perfusion using functional ultrasound in a rat model of transient middle cerebral artery occlusion.

    Science.gov (United States)

    Brunner, Clément; Isabel, Clothilde; Martin, Abraham; Dussaux, Clara; Savoye, Anne; Emmrich, Julius; Montaldo, Gabriel; Mas, Jean-Louis; Baron, Jean-Claude; Urban, Alan

    2017-01-01

    Following middle cerebral artery occlusion, tissue outcome ranges from normal to infarcted depending on depth and duration of hypoperfusion as well as occurrence and efficiency of reperfusion. However, the precise time course of these changes in relation to tissue and behavioral outcome remains unsettled. To address these issues, a three-dimensional wide field-of-view and real-time quantitative functional imaging technique able to map perfusion in the rodent brain would be desirable. Here, we applied functional ultrasound imaging, a novel approach to map relative cerebral blood volume without contrast agent, in a rat model of brief proximal transient middle cerebral artery occlusion to assess perfusion in penetrating arterioles and venules acutely and over six days thanks to a thinned-skull preparation. Functional ultrasound imaging efficiently mapped the acute changes in relative cerebral blood volume during occlusion and following reperfusion with high spatial resolution (100 µm), notably documenting marked focal decreases during occlusion, and was able to chart the fine dynamics of tissue reperfusion (rate: one frame/5 s) in the individual rat. No behavioral and only mild post-mortem immunofluorescence changes were observed. Our study suggests functional ultrasound is a particularly well-adapted imaging technique to study cerebral perfusion in acute experimental stroke longitudinally from the hyper-acute up to the chronic stage in the same subject.

  15. Denoising and artefact reduction in dynamic flat detector CT perfusion imaging using high speed acquisition: first experimental and clinical results.

    Science.gov (United States)

    Manhart, Michael T; Aichert, André; Struffert, Tobias; Deuerling-Zheng, Yu; Kowarschik, Markus; Maier, Andreas K; Hornegger, Joachim; Doerfler, Arnd

    2014-08-21

    Flat detector CT perfusion (FD-CTP) is a novel technique using C-arm angiography systems for interventional dynamic tissue perfusion measurement with high potential benefits for catheter-guided treatment of stroke. However, FD-CTP is challenging since C-arms rotate slower than conventional CT systems. Furthermore, noise and artefacts affect the measurement of contrast agent flow in tissue. Recent robotic C-arms are able to use high speed protocols (HSP), which allow sampling of the contrast agent flow with improved temporal resolution. However, low angular sampling of projection images leads to streak artefacts, which are translated to the perfusion maps. We recently introduced the FDK-JBF denoising technique based on Feldkamp (FDK) reconstruction followed by joint bilateral filtering (JBF). As this edge-preserving noise reduction preserves streak artefacts, an empirical streak reduction (SR) technique is presented in this work. The SR method exploits spatial and temporal information in the form of total variation and time-curve analysis to detect and remove streaks. The novel approach is evaluated in a numerical brain phantom and a patient study. An improved noise and artefact reduction compared to existing post-processing methods and faster computation speed compared to an algebraic reconstruction method are achieved.

  16. Denoising and artefact reduction in dynamic flat detector CT perfusion imaging using high speed acquisition: first experimental and clinical results

    Science.gov (United States)

    Manhart, Michael T.; Aichert, André; Struffert, Tobias; Deuerling-Zheng, Yu; Kowarschik, Markus; Maier, Andreas K.; Hornegger, Joachim; Doerfler, Arnd

    2014-08-01

    Flat detector CT perfusion (FD-CTP) is a novel technique using C-arm angiography systems for interventional dynamic tissue perfusion measurement with high potential benefits for catheter-guided treatment of stroke. However, FD-CTP is challenging since C-arms rotate slower than conventional CT systems. Furthermore, noise and artefacts affect the measurement of contrast agent flow in tissue. Recent robotic C-arms are able to use high speed protocols (HSP), which allow sampling of the contrast agent flow with improved temporal resolution. However, low angular sampling of projection images leads to streak artefacts, which are translated to the perfusion maps. We recently introduced the FDK-JBF denoising technique based on Feldkamp (FDK) reconstruction followed by joint bilateral filtering (JBF). As this edge-preserving noise reduction preserves streak artefacts, an empirical streak reduction (SR) technique is presented in this work. The SR method exploits spatial and temporal information in the form of total variation and time-curve analysis to detect and remove streaks. The novel approach is evaluated in a numerical brain phantom and a patient study. An improved noise and artefact reduction compared to existing post-processing methods and faster computation speed compared to an algebraic reconstruction method are achieved.

  17. Dynamic subcortical blood flow during male sexual activity with ecological validity: a perfusion fMRI study.

    Science.gov (United States)

    Georgiadis, Janniko R; Farrell, Michael J; Boessen, Ruud; Denton, Derek A; Gavrilescu, Maria; Kortekaas, Rudie; Renken, Remco J; Hoogduin, Johannes M; Egan, Gary F

    2010-03-01

    This study used arterial spin labeling (ASL) fMRI to measure brain perfusion in a group of healthy men under conditions that closely resembled customary sexual behavior. Serial perfusion measures for 30 min during two self-limited periods of partnered penis stimulation, and during post-stimulatory periods, revealed novel sexual activity-related cerebral blood flow (rCBF) changes, mainly in subcortical parts of the brain. Ventral pallidum rCBF was highest during the onset of penile erection, and lowest after the termination of penis stimulation. The perceived level of sexual arousal showed the strongest positive association with rCBF in the right basal forebrain. In addition, our results demonstrate that distinct subregions of the hypothalamus and cingulate cortex subserve opposite functions during human male sexual behavior. The lateral hypothalamus and anterior part of the middle cingulate cortex showed increased rCBF correlated with penile erection. By contrast, the anteroventral hypothalamus and subgenual anterior cingulate cortex exhibited rCBF changes correlated with penile detumescence after penile stimulation. Continuous rapid and high-resolution brain perfusion imaging during normal sexual activity has provided novel insights into the central mechanisms that control male sexual arousal. Copyright (c) 2009 Elsevier Inc. All rights reserved.

  18. Clearing of psoriasis documented by laser Doppler perfusion imaging contrasts remaining elevation of dermal expression levels of CD31

    NARCIS (Netherlands)

    Hendriks, A.G.M.; Kerkhof, van de P.C.M.; Jonge, de C.S.; Lucas, M.; Steenbergen, W.; Seyger, M.M.B.

    2015-01-01

    Background Vascular modifications represent a key feature in psoriatic plaques. Previous research with Laser Doppler Perfusion Imaging (LDPI) revealed a remarkable heterogeneity in the cutaneous perfusion within homogenous-appearing psoriatic lesions. Insights in the relation between perfusion durin

  19. Clearing of psoriasis documented by laser Doppler perfusion imaging contrasts remaining elevation of dermal expression levels of CD31

    NARCIS (Netherlands)

    Hendriks, A.G.M.; Kerkhof, P.C.M. van de; Jonge, C.S. de; Lucas, M.; Steenbergen, W.; Seyger, M.M.B.

    2015-01-01

    BACKGROUND: Vascular modifications represent a key feature in psoriatic plaques. Previous research with Laser Doppler Perfusion Imaging (LDPI) revealed a remarkable heterogeneity in the cutaneous perfusion within homogenous-appearing psoriatic lesions. Insights in the relation between perfusion duri

  20. Simultaneous Tc-99m/I-123 Dual Radionuclide Myocardial Perfusion/Innervation Imaging Using Siemens IQ-SPECT with SMARTZOOM Collimator

    OpenAIRE

    Du, Yong; Bhattacharya, Manojeet; Frey, Eric C.

    2014-01-01

    Simultaneous dual-radionuclide myocardial perfusion/innervation SPECT imaging can provide important information about mismatch between scar tissue and denervated regions. The Siemens IQ-SPECT system developed for cardiac imaging uses a multifocal SMARTZOOM collimator to achieve a four-fold sensitivity for the cardiac region compared to a typical parallel-hole low-energy high-resolution collimator but without the data truncation that can result with conventional converging-beam collimators. Th...

  1. New CZT cardiac cameras and myocardial perfusion imaging with thallium 201; Nouvelles cameras cardiaques a semi-conducteur cadmium -zinc- telluride (CZT) et scintigraphies myocardiques au thallium 201

    Energy Technology Data Exchange (ETDEWEB)

    Songy, B. [Service de medecine et imagerie nucleaire, centre cardiologique du Nord (CCN), 93 - Saint-Denis (France)

    2010-08-15

    Myocardial perfusion imaging is widely used for management of coronary artery disease. However, it suffers from technical limitations. New cardiac cameras using CZT detectors are now available and increase spatial (x2) and energy (x2) resolutions and photons sensitivity (x5). We describe here the General Electric Discovery NM 530c new camera and summarize the validation studies with technetium agents and with thallium 201, protocols to reduce doses, ultrafast protocols and perspectives offered with this new technology. (author)

  2. Noise spatial nonuniformity and the impact of statistical image reconstruction in CT myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lauzier, Pascal Theriault; Tang Jie; Speidel, Michael A.; Chen Guanghong [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705-2275 (United States); Department of Medical Physics and Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin 53705-2275 (United States)

    2012-07-15

    Purpose: To achieve high temporal resolution in CT myocardial perfusion imaging (MPI), images are often reconstructed using filtered backprojection (FBP) algorithms from data acquired within a short-scan angular range. However, the variation in the central angle from one time frame to the next in gated short scans has been shown to create detrimental partial scan artifacts when performing quantitative MPI measurements. This study has two main purposes. (1) To demonstrate the existence of a distinct detrimental effect in short-scan FBP, i.e., the introduction of a nonuniform spatial image noise distribution; this nonuniformity can lead to unexpectedly high image noise and streaking artifacts, which may affect CT MPI quantification. (2) To demonstrate that statistical image reconstruction (SIR) algorithms can be a potential solution to address the nonuniform spatial noise distribution problem and can also lead to radiation dose reduction in the context of CT MPI. Methods: Projection datasets from a numerically simulated perfusion phantom and an in vivo animal myocardial perfusion CT scan were used in this study. In the numerical phantom, multiple realizations of Poisson noise were added to projection data at each time frame to investigate the spatial distribution of noise. Images from all datasets were reconstructed using both FBP and SIR reconstruction algorithms. To quantify the spatial distribution of noise, the mean and standard deviation were measured in several regions of interest (ROIs) and analyzed across time frames. In the in vivo study, two low-dose scans at tube currents of 25 and 50 mA were reconstructed using FBP and SIR. Quantitative perfusion metrics, namely, the normalized upslope (NUS), myocardial blood volume (MBV), and first moment transit time (FMT), were measured for two ROIs and compared to reference values obtained from a high-dose scan performed at 500 mA. Results: Images reconstructed using FBP showed a highly nonuniform spatial distribution

  3. Resting state functional connectivity in perfusion imaging: correlation maps with BOLD connectivity and resting state perfusion.

    Directory of Open Access Journals (Sweden)

    Roberto Viviani

    Full Text Available Functional connectivity is a property of the resting state that may provide biomarkers of brain function and individual differences. Classically, connectivity is estimated as the temporal correlation of spontaneous fluctuations of BOLD signal. We investigated differences in connectivity estimated from the BOLD and CBF signal present in volumes acquired with arterial spin labeling technique in a large sample (N = 265 of healthy individuals. Positive connectivity was observable in both BOLD and CBF signal, and was present in the CBF signal also at frequencies lower than 0.009 Hz, here investigated for the first time. Negative connectivity was more variable. The validity of positive connectivity was confirmed by the existence of correlation across individuals in its intensity estimated from the BOLD and CBF signal. In contrast, there was little or no correlation across individuals between intensity of connectivity and mean perfusion levels, suggesting that these two biomarkers correspond to distinct sources of individual differences.

  4. Assessing resolution in super-resolution imaging.

    Science.gov (United States)

    Demmerle, Justin; Wegel, Eva; Schermelleh, Lothar; Dobbie, Ian M

    2015-10-15

    Resolution is a central concept in all imaging fields, and particularly in optical microscopy, but it can be easily misinterpreted. The mathematical definition of optical resolution was codified by Abbe, and practically defined by the Rayleigh Criterion in the late 19th century. The limit of conventional resolution was also achieved in this period, and it was thought that fundamental constraints of physics prevented further increases in resolution. With the recent development of a range of super-resolution techniques, it is necessary to revisit the concept of optical resolution. Fundamental differences in super-resolution modalities mean that resolution is not a directly transferrable metric between techniques. This article considers the issues in resolution raised by these new technologies, and presents approaches for comparing resolution between different super-resolution methods.

  5. Retinal research using the perfused mammalian eye.

    Science.gov (United States)

    Niemeyer, G

    2001-05-01

    applied transiently. This process is monitored histochemically using FITC-albumin and with electrophysiological parameters. Changes in vitreo-scleral resistance and in the amplitude of the EOG-light peak appear to reflect the open/closed status of the barrier. This overview of the uses of the isolated perfused mammalian eye in retinal research concludes with a discussion of potential implications for clinically relevant topics.

  6. Diffusion and Perfusion Magnetic Resonance Imaging:Fundamentals and Advances

    CERN Document Server

    Assili, Sanam

    2016-01-01

    Over the past few decades, magnetic resonance imaging has been utilized as a powerful imaging modality to evaluate the structure and function of various organs in the human body,such as the brain. Additionally, diffusion and perfusion MR imaging have been increasingly used in neurovascular clinical applications. In diffusion-weighted magnetic resonance imaging, the mobility of water molecules is explored in order to obtain information about the microscopic behavior of the tissues. In contrast, perfusion weighted imaging uses tracers to exploit hemodynamic status, which enables researchers and clinicians to consider this imaging modality as an early biomarker of certain brain diseases. In this review, the fundamentals of physics for diffusion and perfusion MR imaging both of which are highly sensitive to microenvironmental alterations at the cellular level as well as their application in the treatment of aging, Alzheimer's disease, brain tumors and cerebral ischemic injury were discussed.

  7. Carotid artery disease and low cerebral perfusion pressure

    DEFF Research Database (Denmark)

    Schroeder, T; Utzon, N P; Aabech, J

    1990-01-01

    Direct internal carotid artery blood pressure measurements in patients undergoing carotid endarterectomy identified 49 patients, among 239 consecutive cases (21%), who had a reduction in perfusion pressure of 20% or more. The clinical history, objective findings and angiographic data were compared...... with those of a control group of a further 49 patients selected from the remaining patients operated on over the same period. The two groups were compared for short- and long-term outcome of surgery. We were unable to delineate a symptomatic neurological profile that identified patients with low perfusion...... pressures. Surgery in patients with low perfusion pressures seemed to be associated with an increased complication rate (12% versus 4%), although this was not statistically significant. Definite postoperative improvements in persisting neurological deficits were observed only in one patient. Long...

  8. Quantitative and qualitative analysis and interpretation of CT perfusion imaging.

    Science.gov (United States)

    Valdiviezo, Carolina; Ambrose, Marietta; Mehra, Vishal; Lardo, Albert C; Lima, Joao A C; George, Richard T

    2010-12-01

    Coronary artery disease (CAD) remains the leading cause of death in the United States. Rest and stress myocardial perfusion imaging has an important role in the non-invasive risk stratification of patients with CAD. However, diagnostic accuracies have been limited, which has led to the development of several myocardial perfusion imaging techniques. Among them, myocardial computed tomography perfusion imaging (CTP) is especially interesting as it has the unique capability of providing anatomic- as well as coronary stenosis-related functional data when combined with computed tomography angiography (CTA). The primary aim of this article is to review the qualitative, semi-quantitative, and quantitative analysis approaches to CTP imaging. In doing so, we will describe the image data required for each analysis and discuss the advantages and disadvantages of each approach.

  9. Regional pulmonary perfusion following human heart-lung transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Lisbona, R.; Hakim, T.S.; Dean, G.W.; Langleben, D.; Guerraty, A.; Levy, R.D. (Royal Victoria Hospital, Montreal, Quebec (Canada))

    1989-08-01

    Ventilation and perfusion scans were obtained in six subjects who had undergone heart-lung transplantation with consequent denervation of the cardiopulmonary axis. Two of the subjects had developed obliterative bronchiolitis, which is believed to be a form of chronic rejection. Their pulmonary function tests demonstrated airflow obstruction and their scintigraphic studies were abnormal. In the remaining four subjects without obstructive airways disease, ventilation and planar perfusion scans were normal. Single photon emission computed tomography imaging of pulmonary perfusion in these patients revealed a layered distribution of blood flow indistinguishable from that of normal individuals. It is concluded that neurogenic mechanisms have little influence on the pattern of local pulmonary blood flow at rest.

  10. Perfusion-weighted MRI of spinal dural arteriovenous fistula

    Energy Technology Data Exchange (ETDEWEB)

    Yanaka, K.; Matsumaru, Y.; Uemura, K.; Matsumura, A.; Nose, T. [Department of Neurosurgery, Institute of Clinical Medicine, University of Tsukuba, Ibaraki (Japan); Anno, I. [Department of Radiology, Institute of Clinical Medicine, University of Tsukuba, Ibaraki (Japan)

    2003-10-01

    A 72-year-old woman was admitted with rapidly progressive paraplegia and sphincter disturbance. T2-weighted images of the thoracic spine showed intramedullary high signal with flow voids suggesting dilated medullary veins. Conventional spinal angiography demonstrated a dural arteriovenous fistula draining into perimedullary veins. Perfusion-weighted MRI demonstrated a prolonged mean transit time and increased blood volume in the high-signal area. The loss of normal perfusion gradient and venous hypertension and were thought to produce these differences. The time-to-peak was almost identical in the high-signal and isointense areas, although the bolus of contrast medium arrived earlier in the former. Arteriovenous shunting was thought to cause faster inflow. These changes may have resulted in increased blood volume in the spinal cord. The high signal has been attributed to oedema due to venous congestion, but there has been no histological confirmation. Perfusion MRI in this case supports this hypothesis. (orig.)

  11. Functional electrical stimulation improves brain perfusion in cranial trauma patients

    Directory of Open Access Journals (Sweden)

    Bárbara Juarez Amorim

    2011-08-01

    Full Text Available OBJECTIVE: Demonstrate brain perfusion changes due to neuronal activation after functional electrical stimulation (FES. METHOD: It was studied 14 patients with hemiplegia who were submitted to a program with FES during fourteen weeks. Brain perfusion SPECT was performed before and after FES therapy. These patients were further separated into 2 groups according to the hemiplegia cause: cranial trauma and major vascular insults. All SPECT images were analyzed using SPM. RESULTS: There was a significant statistical difference between the two groups related to patient's ages and extent of hypoperfusion in the SPECT. Patients with cranial trauma had a reduction in the hypoperfused area and patients with major vascular insult had an increase in the hypoperfused area after FES therapy. CONCLUSION: FES therapy can result in brain perfusion improvement in patients with brain lesions due to cranial trauma but probably not in patients with major vascular insults with large infarct area.

  12. Testosterone biotransformation by the isolated perfused canine pancreas

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-del Castillo, C.; Diaz-Sanchez, V.; Varela-Fascinetto, G.; Altamirano, A.; Odor-Morales, A.; Lopez-Medrano, R.M.; Robles-Diaz, G. (Instituto Nacional de la Nutricion Salvador Zubiran, Mexico City (Mexico))

    1991-01-01

    There is strong evidence indicating that the pancreas is under the influence of sex steroid hormones, and that it may even participate in their biosynthesis and metabolism. In the present study, (3H)testosterone was perfused into the isolated canine pancreas, and measured in the effluent with several of its metabolites (5 alpha-dihydrotestosterone, androstenedione, and estradiol). Results show that testosterone is readily transformed by the canine pancreas. The main product found in the effluent is androstenedione. The testis and spleen were also perfused with (3H)testosterone and used as controls. In both cases, this hormone appeared mostly unchanged in the effluent as compared to the pancreatic perfusion (p less than 0.0001). From our data, we conclude that the canine pancreas has the capacity to transform sex steroid hormones, and could be considered an extragonadal site of sex steroid biosynthesis.

  13. Evaluating acellular versus cellular perfusate composition during prolonged ex vivo lung perfusion after initial cold ischaemia for 24 hours.

    Science.gov (United States)

    Becker, Simon; Steinmeyer, Jasmin; Avsar, Murat; Höffler, Klaus; Salman, Jawad; Haverich, Axel; Warnecke, Gregor; Ochs, Matthias; Schnapper, Anke

    2016-01-01

    Normothermic ex vivo lung perfusion (EVLP) has developed as a powerful technique to evaluate particularly marginal donor lungs prior to transplantation. In this study, acellular and cellular perfusate compositions were compared in an identical experimental setting as no consensus has been reached on a preferred technique yet. Porcine lungs underwent EVLP for 12 h on the basis of an acellular or a cellular perfusate composition after 24 h of cold ischaemia as defined organ stress. During perfusion, haemodynamic and respiratory parameters were monitored. Aft