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Sample records for diffusion imaging spectroscopy

  1. Resolving Fast, Confined Diffusion in Bacteria with Image Correlation Spectroscopy.

    Science.gov (United States)

    Rowland, David J; Tuson, Hannah H; Biteen, Julie S

    2016-05-24

    By following single fluorescent molecules in a microscope, single-particle tracking (SPT) can measure diffusion and binding on the nanometer and millisecond scales. Still, although SPT can at its limits characterize the fastest biomolecules as they interact with subcellular environments, this measurement may require advanced illumination techniques such as stroboscopic illumination. Here, we address the challenge of measuring fast subcellular motion by instead analyzing single-molecule data with spatiotemporal image correlation spectroscopy (STICS) with a focus on measurements of confined motion. Our SPT and STICS analysis of simulations of the fast diffusion of confined molecules shows that image blur affects both STICS and SPT, and we find biased diffusion rate measurements for STICS analysis in the limits of fast diffusion and tight confinement due to fitting STICS correlation functions to a Gaussian approximation. However, we determine that with STICS, it is possible to correctly interpret the motion that blurs single-molecule images without advanced illumination techniques or fast cameras. In particular, we present a method to overcome the bias due to image blur by properly estimating the width of the correlation function by directly calculating the correlation function variance instead of using the typical Gaussian fitting procedure. Our simulation results are validated by applying the STICS method to experimental measurements of fast, confined motion: we measure the diffusion of cytosolic mMaple3 in living Escherichia coli cells at 25 frames/s under continuous illumination to illustrate the utility of STICS in an experimental parameter regime for which in-frame motion prevents SPT and tight confinement of fast diffusion precludes stroboscopic illumination. Overall, our application of STICS to freely diffusing cytosolic protein in small cells extends the utility of single-molecule experiments to the regime of fast confined diffusion without requiring advanced

  2. MR diffusion imaging and 1H spectroscopy in a child with medulloblastoma: A case report

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    Wilke, M. [Max-Planck-Institute of Psychiatry, Muenchen (Germany). NMR Study Group; Eidenschink, A.; Mueller-Weihrich, S. [Technical Univ. of Muenchen, (Germany). Childrens' Hospital; Auer, D.P. [Max-Planck-Institute of Psychiatry, Muenchen (Germany). NMR Study Group

    2000-01-01

    We report on a child with a metastasising medulloblastoma which was assessed by MR diffusion imaging and 1H MR spectroscopy (MRS). Reduced mean apparent diffusion coefficients and a high amount of taurine could be demonstrated. This is the first reported case of high taurine in medulloblastoma in vivo and confirms earlier in vitro findings. It is suggested that the changes on diffusion imaging, possibly reflecting the small-cell histology of the tumour and high taurine in MRS, are indicative of medulloblastoma.

  3. MR diffusion imaging and 1H spectroscopy in a child with medulloblastoma: A case report

    International Nuclear Information System (INIS)

    Wilke, M.; Eidenschink, A.; Mueller-Weihrich, S.; Auer, D.P.

    2000-01-01

    We report on a child with a metastasising medulloblastoma which was assessed by MR diffusion imaging and 1H MR spectroscopy (MRS). Reduced mean apparent diffusion coefficients and a high amount of taurine could be demonstrated. This is the first reported case of high taurine in medulloblastoma in vivo and confirms earlier in vitro findings. It is suggested that the changes on diffusion imaging, possibly reflecting the small-cell histology of the tumour and high taurine in MRS, are indicative of medulloblastoma

  4. Actinomycotic brain infection: registered diffusion, perfusion MR imaging and MR spectroscopy

    International Nuclear Information System (INIS)

    Wang, Sumei; Wolf, Ronald L.; Woo, John H.; Melhem, Elias R.; Poptani, Harish; Wang, Jiongjiong; O'Rourke, Donald M.; Roy, Subhojit

    2006-01-01

    Introduction: Actinomycotic brain infection is caused by an organism of the Actinomyces genus. We report here one such case. Methods: The methods used included coregistered diffusion, perfusion and spectroscopic magnetic resonance (MR) imaging. Decreased apparent diffusion coefficient, markedly elevated fractional anisotropy (FA) and reduced cerebral blood flow were observed. MR spectroscopy demonstrated elevated amino acids, acetate and succinate. Elevated FA values may be due to the microstructure of this special brain infection. (orig.)

  5. MR diffusion imaging and MR spectroscopy of maple syrup urine disease during acute metabolic decompensation

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    Jan, Wajanat; Wang, Zhiyue J. [Department of Radiology, University of Pennsylvania School of Medicine, Children' s Hospital of Philadelphia, Pennsylvania (United States); Zimmerman, Robert A. [Department of Radiology, University of Pennsylvania School of Medicine, Children' s Hospital of Philadelphia, Pennsylvania (United States); Department of Radiology, Children' s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, PA 19104, Philadelphia (United States); Berry, Gerard T.; Kaplan, Paige B.; Kaye, Edward M. [Department of Pediatrics, University of Pennsylvania School of Medicine, The Children' s Hospital of Philadelphia, Philadelphia, Pennsylvania (United States)

    2003-06-01

    Maple syrup urine disease (MSUD) is an inborn error of amino acid metabolism, which affects the brain tissue resulting in impairment or death if untreated. Imaging studies have shown reversible brain edema during acute metabolic decompensation. The purpose of this paper is to describe the diffusion-weighted imaging (DWI) and spectroscopy findings during metabolic decompensation and to assess the value of these findings in the prediction of patient outcome. Six patients with the diagnosis of MSUD underwent conventional MR imaging with DWI during acute presentation with metabolic decompensation. Spectroscopy with long TE was performed in four of the six patients. Follow-up examinations were performed after clinical and metabolic recovery. DWI demonstrated marked restriction of proton diffusion compatible with cytotoxic or intramyelinic sheath edema in the brainstem, basal ganglia, thalami, cerebellar and periventricular white matter and the cerebral cortex. This was accompanied by the presence of an abnormal branched-chain amino acids (BCAA) and branched-chain alpha-keto acids (BCKA) peak at 0.9 ppm as well as elevated lactate on proton spectroscopy in all four patients. The changes in all six patients were reversed with treatment without evidence of volume loss or persistent tissue damage. The presence of cytotoxic or intramyelinic edema as evidenced by restricted water diffusion on DWI, with the presence of lactate on spectroscopy, could imply imminent cell death. However, in the context of metabolic decompensation in MSUD, it appears that changes in cell osmolarity and metabolism can reverse completely after metabolic correction. (orig.)

  6. MR diffusion imaging and MR spectroscopy of maple syrup urine disease during acute metabolic decompensation

    International Nuclear Information System (INIS)

    Jan, Wajanat; Wang, Zhiyue J.; Zimmerman, Robert A.; Berry, Gerard T.; Kaplan, Paige B.; Kaye, Edward M.

    2003-01-01

    Maple syrup urine disease (MSUD) is an inborn error of amino acid metabolism, which affects the brain tissue resulting in impairment or death if untreated. Imaging studies have shown reversible brain edema during acute metabolic decompensation. The purpose of this paper is to describe the diffusion-weighted imaging (DWI) and spectroscopy findings during metabolic decompensation and to assess the value of these findings in the prediction of patient outcome. Six patients with the diagnosis of MSUD underwent conventional MR imaging with DWI during acute presentation with metabolic decompensation. Spectroscopy with long TE was performed in four of the six patients. Follow-up examinations were performed after clinical and metabolic recovery. DWI demonstrated marked restriction of proton diffusion compatible with cytotoxic or intramyelinic sheath edema in the brainstem, basal ganglia, thalami, cerebellar and periventricular white matter and the cerebral cortex. This was accompanied by the presence of an abnormal branched-chain amino acids (BCAA) and branched-chain alpha-keto acids (BCKA) peak at 0.9 ppm as well as elevated lactate on proton spectroscopy in all four patients. The changes in all six patients were reversed with treatment without evidence of volume loss or persistent tissue damage. The presence of cytotoxic or intramyelinic edema as evidenced by restricted water diffusion on DWI, with the presence of lactate on spectroscopy, could imply imminent cell death. However, in the context of metabolic decompensation in MSUD, it appears that changes in cell osmolarity and metabolism can reverse completely after metabolic correction. (orig.)

  7. Sodium Chloride Diffusion during Muscle Salting Evidenced by Energy-Dispersive X-ray Spectroscopy Imaging.

    Science.gov (United States)

    Filgueras, Rénata; Peyrin, Frédéric; Vénien, Annie; Hénot, Jean Marc; Astruc, Thierry

    2016-01-27

    To better understand the relationship between the muscle structure and NaCl transfers in meat, we used energy-dispersive X-ray spectroscopy (EDS) coupled with scanning electron microscopy (SEM) to analyze brined and dry-salted rat muscles. The muscles were freeze-dried to avoid the delocalization of soluble ions that happens in regular dehydration through a graded series of ethanol. Na and Cl maps were superimposed on SEM images to combine the muscle structure and NaCl diffusion. Brining causes rapid diffusion of NaCl through the tissue. Most brine diffuses in a linear front from the muscle surface, but a small proportion enters through the perimysium network. The muscle area penetrated by brine shows heterogeneous patterns of NaCl retention, with some connective tissue islets containing more NaCl than other parts of perimysium. NaCl penetration is considerably slower after dry salting than after brining.

  8. Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

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    Fonte, Mariana Vieira de Melo da; Otaduy, Maria Concepcion Garcia; Lucato, Leandro Tavares; Reed, Umbertina Conti; Leite, Claudia da Costa [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Inst. de Radiologia]. E-mail: mvmfonte@uol.com.br; Costa, Maria Olivia Rodrigues; Amaral, Raquel Portugal Guimaraes [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Radiologia; Reed, Umbertina Conti [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Neurologia; Rosemberg, Sergio [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Dept. de Patologia

    2008-11-15

    To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T 1-weighted images and intermediate/hyperintense on T 2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Na a / Cr ratio (83.3%) and increased Co/Cr (100%) and ml/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. (author)

  9. Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Fonte, Mariana Vieira de Melo da; Otaduy, Maria Concepcion Garcia; Lucato, Leandro Tavares; Reed, Umbertina Conti; Leite, Claudia da Costa; Costa, Maria Olivia Rodrigues; Amaral, Raquel Portugal Guimaraes; Reed, Umbertina Conti; Rosemberg, Sergio

    2008-01-01

    To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T 1-weighted images and intermediate/hyperintense on T 2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Na a / Cr ratio (83.3%) and increased Co/Cr (100%) and ml/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. (author)

  10. Intracranial metastatic mucinous adrenocarcinoma with characteristic features on diffusion-weighted imaging and in vivo magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Guruprasad, Ashwathnarayan S.; Chandrashekar, Hoskote S.; Jayakumar, Peruvumba N.; Srikanth, Subbamma G.; Shankar, Susarla K.

    2004-01-01

    Intracranial abscesses and metastases are common lesions that might not be differentiated on routine MR I alone. In vivo proton spectroscopy and diffusion-weighted imaging have been used as complementary investigations for improved tissue characterization. In the present report we illustrate the role of mucin and its contribution to signal characteristics on diffusion-weighted imaging in a metastatic mucinous adenocarcinoma Copyright (2004) Blackwell Publishing Asia Pty Ltd

  11. Diffusion-weighted imaging and proton MR spectroscopy in the characterization of acute disseminated encephalomyelitis

    International Nuclear Information System (INIS)

    Balasubramanya, K.S.; Kovoor, J.M.E.; Jayakumar, P.N.; Ravishankar, S.; Kamble, R.B.; Panicker, J.; Nagaraja, D.

    2007-01-01

    Acute disseminated encephalomyelitis (ADEM) is usually a monophasic illness characterized by multiple lesions involving gray and white matter. Quantitative MR techniques were used to characterize and stage these lesions. Eight patients (seven males and one female; mean age 19 years, range 5 to 36 years) were studied using conventional MRI (T2- and T1-weighted and FLAIR sequences), diffusion-weighted imaging (DWI) and proton magnetic resonance spectroscopy (MRS). Apparent diffusion coefficient (ADC) values and MRS ratios were calculated for the lesion and for normal-appearing white matter (NAWM). Three patients were imaged in the acute stage (within 7 days of the onset of neurological symptoms) and five in the subacute stage (after 7 days from the onset of symptoms). ADC values in NAWM were in the range 0.7-1.24 x 10 -3 mm/s 2 (mean 0.937 ± 0.17 mm/s 2 ). ADC values of ADEM lesions in the acute stage were in the range 0.37-0.68 x 10 -3 mm/s 2 (mean 0.56 ± 0.16 mm/s 2 ) and 1.01-1.31 x 10 -3 mm/s 2 (mean 1.24 ± 0.13 mm/s 2 ) in the subacute stage. MRS ratios were obtained for all patients. NAA/Cho ratios were in the range 1.1-3.5 (mean 1.93 ± 0.86) in the NAWM. NAA/Cho ratios within ADEM lesions in the acute stage were in the range 0.63-1.48 (mean 1.18 ± 0.48) and 0.29-0.84 (mean 0.49 ± 0.22) in the subacute stage. The ADC values, NAA/Cho and Cho/Cr ratios were significantly different between lesions in the acute and subacute stages (P < 0.001, P < 0.027, P < 0.047, respectively). ADC values were significantly different between lesions in the acute (P < 0.009) and subacute stages (P < 0.005) with NAWM. In addition, NAA/Cho and Cho/Cr ratios were significantly different between lesions in the subacute stage and NAWM (P < 0.006, P < 0.007, respectively). ADEM lesions were characterized in the acute stage by restricted diffusion and in the subacute stage by free diffusion and a decrease in NAA/Cho ratios. Restricted diffusion and progressive decrease in NAA

  12. Diffusion-weighted imaging and proton MR spectroscopy in the characterization of acute disseminated encephalomyelitis

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    Balasubramanya, K.S.; Kovoor, J.M.E.; Jayakumar, P.N.; Ravishankar, S.; Kamble, R.B. [National Institute of Mental Health and Neurosciences, Department of Neuroimaging and Interventional Radiology, Bangalore, Karnataka (India); Panicker, J.; Nagaraja, D. [National Institute of Mental Health and Neurosciences, Department of Neurology, Bangalore (India)

    2007-02-15

    Acute disseminated encephalomyelitis (ADEM) is usually a monophasic illness characterized by multiple lesions involving gray and white matter. Quantitative MR techniques were used to characterize and stage these lesions. Eight patients (seven males and one female; mean age 19 years, range 5 to 36 years) were studied using conventional MRI (T2- and T1-weighted and FLAIR sequences), diffusion-weighted imaging (DWI) and proton magnetic resonance spectroscopy (MRS). Apparent diffusion coefficient (ADC) values and MRS ratios were calculated for the lesion and for normal-appearing white matter (NAWM). Three patients were imaged in the acute stage (within 7 days of the onset of neurological symptoms) and five in the subacute stage (after 7 days from the onset of symptoms). ADC values in NAWM were in the range 0.7-1.24 x 10{sup -3} mm/s{sup 2} (mean 0.937 {+-} 0.17 mm/s{sup 2}). ADC values of ADEM lesions in the acute stage were in the range 0.37-0.68 x 10{sup -3} mm/s{sup 2} (mean 0.56 {+-} 0.16 mm/s{sup 2}) and 1.01-1.31 x 10{sup -3} mm/s{sup 2} (mean 1.24 {+-} 0.13 mm/s{sup 2}) in the subacute stage. MRS ratios were obtained for all patients. NAA/Cho ratios were in the range 1.1-3.5 (mean 1.93 {+-} 0.86) in the NAWM. NAA/Cho ratios within ADEM lesions in the acute stage were in the range 0.63-1.48 (mean 1.18 {+-} 0.48) and 0.29-0.84 (mean 0.49 {+-} 0.22) in the subacute stage. The ADC values, NAA/Cho and Cho/Cr ratios were significantly different between lesions in the acute and subacute stages (P < 0.001, P < 0.027, P < 0.047, respectively). ADC values were significantly different between lesions in the acute (P < 0.009) and subacute stages (P < 0.005) with NAWM. In addition, NAA/Cho and Cho/Cr ratios were significantly different between lesions in the subacute stage and NAWM (P < 0.006, P < 0.007, respectively). ADEM lesions were characterized in the acute stage by restricted diffusion and in the subacute stage by free diffusion and a decrease in NAA/Cho ratios

  13. Heroin-induced leukoencephalopathy: characterization using MRI, diffusion-weighted imaging, and MR spectroscopy

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    Offiah, C. [Department of Neuroradiology, St Bartholomew' s and the London Hospitals NHS Trust, London (United Kingdom); Hall, E. [Department of Neuroradiology, St Bartholomew' s and the London Hospitals NHS Trust, London (United Kingdom)], E-mail: curtis.offiah@bartsandthelondon.nhs.uk

    2008-02-15

    Aim: To describe the magnetic resonance imaging (MRI) characteristics of heroin-induced leukoencephalopathy or 'chasing the dragon syndrome' and, in particular, the diffusion-weighted imaging (DWI) and MR spectroscopy (MRS) features. Material and methods: Six patients with a clinical or histopathological diagnosis of heroin-induced leukoencephalopathy were identified and MRI examinations, including DWI and single-voxel MRS, reviewed. Results: Cerebellar white matter was involved in all six cases demonstrating similar symmetrical distribution with sparing of the dentate nuclei. Brain stem signal change was evident in five of the six patients imaged. Supratentorial brain parenchymal involvement, as well as brain stem involvement, correlated anatomically with corticospinal tract distribution. None of the areas of signal abnormality were restricted on DWI. Of those patients subjected to MRS, the areas of parenchymal damage demonstrated reduced N-acetylaspartate, reduced choline, and elevated lactate. Conclusion: Heroin-induced leukoencephalopathy results in characteristic and highly specific signal abnormalities on MRI, which can greatly aid diagnosis. DWI and MRS findings can be explained by known reported neuropathological descriptions in this condition and can be used to support a proposed mechanism for the benefit of current recommended drug treatment regimes.

  14. Differentiation of intracranial tuberculomas and high grade gliomas using proton MR spectroscopy and diffusion MR imaging

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    Peng, Juan, E-mail: pengjuan1209@126.com [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China); Ouyang, Yu, E-mail: 1957ouyangyu@sina.com [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China); Fang, Wei-Dong, E-mail: fwd9707@yahoo.com.cn [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China); Luo, Tian-You, E-mail: ltychy@sina.com [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China); Li, Yong-Mei, E-mail: lymzhang70@yahoo.com.cn [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China); Lv, Fa-Jin, E-mail: fajinlv@hotmail.com [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China); Zhang, Zhi-Wei, E-mail: jintianzzw@163.com [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China); Li, Xin-You, E-mail: lixinyou666@163.com [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China)

    2012-12-15

    Objective: The purpose of this study was to determine whether proton MR spectroscopy ({sup 1}H MRS) and diffusion-weighted (DW) imaging can be used to differentiate intracranial tuberculomas from high grade gliomas (HGGs). Materials and methods: A total of 41 patients (19 with intracranial tuberculomas and 22 with HGGs) were examined in our study. {sup 1}H MRS and DW imaging were performed at a 1.5T MR scanner before operation or treatment. Concentrations of N-acetylaspartate (NAA), creatine (Cr), choline (Cho), and lipid and lactate (LL) in the contrast-enhancing rim of each lesion were expressed as metabolite ratios and were normalized to the contralateral hemisphere. The apparent diffusion coefficient (ADC) was also calculated. The metabolite ratios and ADC values in the enhancing rim of intracranial tuberculomas and HGGs were compared using the Wilcoxon rank sum test. Diagnostic accuracy was compared using receiver operating characteristic (ROC) analysis. Results: Significant differences were found in the maximum Cho/Cr (P = 0.015), Cho/NAA (P = 0.001) and Cho/Cho-n ratios (P = 0.002), and minimum ADC value (P < 0.001) between the intracranial tuberculomas and HGGs. Diagnostic accuracy was higher by minimum ADC value than maximum Cho/Cr, Cho/NAA and Cho/Cho-n ratios (93.8% versus 75.7%, 80.8% and 78.1%). Conclusion: These results suggest a promising role for {sup 1}H MRS and DW imaging in the differentiation between the intracranial tuberculomas and HGGs.

  15. Easy measurement of diffusion coefficients of EGFP-tagged plasma membrane proteins using k-space Image Correlation Spectroscopy

    DEFF Research Database (Denmark)

    Christensen, Eva Arnspang; Koffman, Jennifer Skaarup; Marlar, Saw

    2014-01-01

    Lateral diffusion and compartmentalization of plasma membrane proteins are tightly regulated in cells and thus, studying these processes will reveal new insights to plasma membrane protein function and regulation. Recently, k-Space Image Correlation Spectroscopy (kICS)1 was developed to enable...... routine measurements of diffusion coefficients directly from images of fluorescently tagged plasma membrane proteins, that avoided systematic biases introduced by probe photophysics. Although the theoretical basis for the analysis is complex, the method can be implemented by nonexperts using a freely...... to the correlation function yields the diffusion coefficient. This paper provides a step-by-step guide to the image analysis and measurement of diffusion coefficients via kICS. First, a high frame rate image sequence of a fluorescently labeled plasma membrane protein is acquired using a fluorescence microscope Then...

  16. Diffuse reflectance spectroscopy and optical polarization imaging of in-vivo biological tissue

    Science.gov (United States)

    Mora-Núñez, A.; Castillejos, Y.; García-Torales, G.; Martínez-Ponce, G.

    2013-11-01

    A number of optical techniques have been reported in the scientific literature as accomplishable methodologies to diagnose diseases in biological tissue, for instance, diffuse reflectance spectroscopy (DRS) and optical polarization imaging (OPI). The skin is the largest organ in the body and consists of three primary layers, namely, the epidermis (the outermost layer exposed to the world), the dermis, and the hypodermis. The epidermis changes from to site to site, mainly because of difference in hydration. A lower water content increase light scattering and reduce the penetration depth of radiation. In this work, two hairless mice have been selected to evaluate their skin features by using DRS and OPI. Four areas of the specimen body were chosen to realize the comparison: back, abdomen, tail, and head. From DRS, it was possible to distinguish the skin nature because of different blood irrigation at dermis. In the other hand, OPI shows pseudo-depolarizing regions in the measured Mueller images related to a spatially varying propagation of the scattered light. This provides information about the cell size in the irradiated skin.

  17. Prediction of post-operative necrosis after mastectomy: A pilot study utilizing optical diffusion imaging spectroscopy

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    Xie Xian-Jin

    2009-11-01

    Full Text Available Abstract Introduction Flap necrosis and epidermolysis occurs in 18-30% of all mastectomies. Complications may be prevented by intra-operative detection of ischemia. Currently, no technique enables quantitative valuation of mastectomy skin perfusion. Optical Diffusion Imaging Spectroscopy (ViOptix T.Ox Tissue Oximeter measures the ratio of oxyhemoglobin to deoxyhemoglobin over a 1 × 1 cm area to obtain a non-invasive measurement of perfusion (StO2. Methods This study evaluates the ability of ViOptix T.Ox Tissue Oximeter to predict mastectomy flap necrosis. StO2 measurements were taken at five points before and at completion of dissection in 10 patients. Data collected included: demographics, tumor size, flap length/thickness, co-morbidities, procedure length, and wound complications. Results One patient experienced mastectomy skin flap necrosis. Five patients underwent immediate reconstruction, including the patient with necrosis. Statistically significant factors contributing to necrosis included reduction in medial flap StO2 (p = 0.0189, reduction in inferior flap StO2 (p = 0.003, and flap length (p = 0.009. Conclusion StO2 reductions may be utilized to identify impaired perfusion in mastectomy skin flaps.

  18. Diffusion-weighted imaging and magnetic resonance proton spectroscopy following preterm birth

    International Nuclear Information System (INIS)

    Hart, A.R.; Smith, M.F.; Whitby, E.H.; Alladi, S.; Wilkinson, S.; Paley, M.N.; Griffiths, P.D.

    2014-01-01

    Aim: To study the associations between magnetic resonance proton spectroscopy (MRS) data and apparent diffusion coefficients (ADC) from the preterm brain with developmental outcome at 18 months corrected age and clinical variables. Materials and methods: A prospective observational cohort study of 67 infants born before 35 weeks gestational age who received both magnetic resonance imaging of the brain between 37 and 44 weeks corrected gestational age and developmental assessment around 18 months corrected age. Results: No relationships were found between ADC values and MRS results or outcome. MRS ratios involving N-acetyl aspartate (NAA) from the posterior white matter were associated with ''severe'' and ''moderate to severe'' difficulties, and fine motor scores were significantly lower in participants with a visible lactate doublet in the posterior white matter. The presence of a patent ductus arteriosus (PDA) was the only clinical factor related to NAA ratios. Conclusion: Altered NAA levels in the posterior white matter may reflect subtle white matter injury associated with neuro-developmental difficulties, which may be related to a PDA. Further work is needed to assess the longer-term neuro-developmental implications of these findings, and to study the effect of PDAs on developmental outcome in later childhood/adolescence. - Highlights: • ADC values around term corrected age from a wide area of the brain are not associated with developmental outcome. • NAA ratios from the posterior white matter are associated with adverse outcome. • No relationship between MRS data and ADC values exist when measured from the same region of the cerebral white matter. • The presence of a patent ductus arterious was associated with NAA ratios from the posterior white matter, but not outcome

  19. Interhemispheric connectivity in amyotrophic lateral sclerosis: A near-infrared spectroscopy and diffusion tensor imaging study.

    Science.gov (United States)

    Kopitzki, Klaus; Oldag, Andreas; Sweeney-Reed, Catherine M; Machts, Judith; Veit, Maria; Kaufmann, Jörn; Hinrichs, Hermann; Heinze, Hans-Jochen; Kollewe, Katja; Petri, Susanne; Mohammadi, Bahram; Dengler, Reinhard; Kupsch, Andreas R; Vielhaber, Stefan

    2016-01-01

    Aim of the present study was to investigate potential impairment of non-motor areas in amyotrophic lateral sclerosis (ALS) using near-infrared spectroscopy (NIRS) and diffusion tensor imaging (DTI). In particular, we evaluated whether homotopic resting-state functional connectivity (rs-FC) of non-motor associated cortical areas correlates with clinical parameters and disease-specific degeneration of the corpus callosum (CC) in ALS. Interhemispheric homotopic rs-FC was assessed in 31 patients and 30 healthy controls (HCs) for 8 cortical sites, from prefrontal to occipital cortex, using NIRS. DTI was performed in a subgroup of 21 patients. All patients were evaluated for cognitive dysfunction in the executive, memory, and visuospatial domains. ALS patients displayed an altered spatial pattern of correlation between homotopic rs-FC values when compared to HCs ( p  = 0.000013). In patients without executive dysfunction a strong correlation existed between the rate of motor decline and homotopic rs-FC of the anterior temporal lobes (ATLs) (ρ = - 0.85, p  = 0.0004). Furthermore, antero-temporal homotopic rs-FC correlated with fractional anisotropy in the central corpus callosum (CC), corticospinal tracts (CSTs), and forceps minor as determined by DTI ( p  < 0.05). The present study further supports involvement of non-motor areas in ALS. Our results render homotopic rs-FC as assessed by NIRS a potential clinical marker for disease progression rate in ALS patients without executive dysfunction and a potential anatomical marker for ALS-specific degeneration of the CC and CSTs.

  20. Diffusion-weighted imaging-guided MR spectroscopy in breast lesions using readout-segmented echo-planar imaging

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    Sun, Kun; Chai, Weimin; Zhan, Ying; Luo, Xianfu; Yan, Fuhua [Shanghai Jiao Tong University School of Medicine, Department of Radiology, Ruijin Hospital, Shanghai (China); Fu, Caixia [Siemens MRI Center, Siemens Shenzhen Magnetic Resonance Ltd, Shenzhen (China); Shen, Kunwei [Shanghai Jiao Tong University School of Medicine, Comprehensive Breast Health Center, Ruijin Hospital, Shanghai (China)

    2016-06-15

    To investigate the feasibility and effectiveness of diffusion-weighted imaging (DWI)-guided magnetic resonance spectroscopy (MRS) using readout-segmented echo-planar imaging (RS-EPI) to characterise breast lesions. A total of 258 patients with 258 suspicious breast lesions larger than 1 cm in diameter were examined using DWI-guided, single-voxel MRS with RS-EPI. The mean total choline-containing compound (tCho) signal-to-noise ratio (SNR) and concentration were used for the interpretation of MRS data. T-tests, χ{sup 2}-tests, receiver operating characteristic (ROC) curve analyses and Pearson correlations were conducted for statistical analysis. Histologically, 183 lesions were malignant, and 75 lesions were benign. Both the mean tCho SNR and concentration of malignant lesions were higher than those of benign lesions (6.23 ± 3.30 AU/mL vs. 1.26 ± 1.75 AU/mL and 3.17 ± 2.03 mmol/kg vs. 0.86 ± 0.83 mmol/kg, respectively; P < 0.0001). For a tCho SNR of 2.0 AU/mL and a concentration of 1.76 mmol/kg, the corresponding areas under the ROC curves were 0.93 and 0.90, respectively. The mean tCho SNR and concentration negatively correlated with apparent diffusion coefficients calculated from RS-EPI, with correlation coefficients of -0.54 and -0.48, respectively. DWI-guided MRS using RS-EPI is feasible and accurate for characterising breast lesions. (orig.)

  1. Diffusion measurements by Raman spectroscopy

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Shapiro, Alexander; Berg, Rolf W.

    Poster "Diffusion measurements by Raman spectroscopy", See poster at http://www.kemi.dtu.dk/~ajo/rolf/petroday2004.ppt......Poster "Diffusion measurements by Raman spectroscopy", See poster at http://www.kemi.dtu.dk/~ajo/rolf/petroday2004.ppt...

  2. Time-Resolved Diffuse Optical Spectroscopy and Imaging Using Solid-State Detectors: Characteristics, Present Status, and Research Challenges.

    Science.gov (United States)

    Alayed, Mrwan; Deen, M Jamal

    2017-09-14

    Diffuse optical spectroscopy (DOS) and diffuse optical imaging (DOI) are emerging non-invasive imaging modalities that have wide spread potential applications in many fields, particularly for structural and functional imaging in medicine. In this article, we review time-resolved diffuse optical imaging (TR-DOI) systems using solid-state detectors with a special focus on Single-Photon Avalanche Diodes (SPADs) and Silicon Photomultipliers (SiPMs). These TR-DOI systems can be categorized into two types based on the operation mode of the detector (free-running or time-gated). For the TR-DOI prototypes, the physical concepts, main components, figures-of-merit of detectors, and evaluation parameters are described. The performance of TR-DOI prototypes is evaluated according to the parameters used in common protocols to test DOI systems particularly basic instrumental performance (BIP). In addition, the potential features of SPADs and SiPMs to improve TR-DOI systems and expand their applications in the foreseeable future are discussed. Lastly, research challenges and future developments for TR-DOI are discussed for each component in the prototype separately and also for the entire system.

  3. Analysis of the human brain in primary progressive multiple sclerosis with mapping of the spatial distributions using H-1 MR spectroscopy and diffusion tensor imaging

    NARCIS (Netherlands)

    Sijens, PE; Irwan, R; Potze, JH; Mostert, JP; De Keyser, J; Oudkerk, M

    Primary progressive multiple sclerosis (ppMS; n=4) patients and controls (n=4) were examined by 1H magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI) in order to map choline (Cho), creatine and N-acetylaspartate (NAA), the fractional anisotropy (FA) and the apparent diffusion

  4. Brain changes in long-term zen meditators using proton magnetic resonance spectroscopy and diffusion tensor imaging: a controlled study.

    Directory of Open Access Journals (Sweden)

    Nicolás Fayed

    Full Text Available INTRODUCTION: This work aimed to determine whether (1H magnetic resonance imaging (MRI, magnetic resonance spectroscopy (MRS, diffusion-weighted imaging (DWI and diffusion tensor imaging (DTI are correlated with years of meditation and psychological variables in long-term Zen meditators compared to healthy non-meditator controls. MATERIALS AND METHODS: Design. Controlled, cross-sectional study. Sample. Meditators were recruited from a Zen Buddhist monastery. The control group was recruited from hospital staff. Meditators were administered questionnaires on anxiety, depression, cognitive impairment and mindfulness. (1H-MRS (1.5 T of the brain was carried out by exploring four areas: both thalami, both hippocampi, the posterior superior parietal lobule (PSPL and posterior cingulate gyrus. Predefined areas of the brain were measured for diffusivity (ADC and fractional anisotropy (FA by MR-DTI. RESULTS: Myo-inositol (mI was increased in the posterior cingulate gyrus and Glutamate (Glu, N-acetyl-aspartate (NAA and N-acetyl-aspartate/Creatine (NAA/Cr was reduced in the left thalamus in meditators. We found a significant positive correlation between mI in the posterior cingulate and years of meditation (r = 0.518; p = .019. We also found significant negative correlations between Glu (r = -0.452; p = .045, NAA (r = -0.617; p = .003 and NAA/Cr (r = -0.448; P = .047 in the left thalamus and years of meditation. Meditators showed a lower Apparent Diffusion Coefficient (ADC in the left posterior parietal white matter than did controls, and the ADC was negatively correlated with years of meditation (r = -0.4850, p = .0066. CONCLUSIONS: The results are consistent with the view that mI, Glu and NAA are the most important altered metabolites. This study provides evidence of subtle abnormalities in neuronal function in regions of the white matter in meditators.

  5. The imaging study on the value of 1H-MR spectroscopy in diffuse axonal injury

    International Nuclear Information System (INIS)

    Xia Haijian; Sun Xiaochuan; Tang Wenyuan; Zheng Lvping

    2007-01-01

    Objective: To investigate the value of 1 H-MRS in the diagnosis and prognosis of diffuse axonal injury (DAI). Methods: A prospective imaging study was performed in 63 patients with craniocerebral injury admitted from October 2002 to April 2004. Sixty-three patients were divided into DAI group (27 cases) and Non-DAI group (36 cases) according to the result of the MRI. Then, the ratio of NAA/Cr, Cho/Cr, mINs/Cr, and Glx/Cr at basal ganglia and genu and splenium of corpus callosum was quantified using 1 H-MRS and compared between DAI group and Non-DAI group. Twenty healthy persons were served as control group. The relation between 1 H-MRS indexes and period of primary unconciousness post-injury was analyzed. Results: The results of NAA/Cr and Cho/Cr at genu and splenium of corpus callosum and basal ganglia of control group were 1.19 ± 0.18, 1.21 ± 0.24; 1.89 ± 0.17, 1.84 ± 0.14; 1.57 ± 0.16, 1.85 ± 0.25, which of DAI group were 0.83 ± 0.24, 2.92 ± 0.78; 1.25 ± 0.35, 2.54 ± 0.42; 1.33 ± 0.17, 2.38 ± 0.44, and those of Non-DAI group were 1.11 ± 0.23, 1.61 ± 0.33; 1.61 ± 0.22, 1.93 ± 0.26; 1.49 ± 0.23, 1.89 ± 0.29. The differences between them were statistically significant (P 1 H-MRS is a noninvasive modality in vivo for assessing the metabolic status of the brain after TBI and can detect the changes of cellular and molecular pathophysiology. 1 H-MRS is beneficial to provide additional information for DAf diagnosis, which can be used to evaluate injury severity, predict prognosis and guide treatment. (authors)

  6. Brain Changes in Long-Term Zen Meditators Using Proton Magnetic Resonance Spectroscopy and Diffusion Tensor Imaging: A Controlled Study

    Science.gov (United States)

    Fayed, Nicolás; Lopez del Hoyo, Yolanda; Andres, Eva; Serrano-Blanco, Antoni; Bellón, Juan; Aguilar, Keyla; Cebolla, Ausias; Garcia-Campayo, Javier

    2013-01-01

    Introduction This work aimed to determine whether 1H magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) are correlated with years of meditation and psychological variables in long-term Zen meditators compared to healthy non-meditator controls. Materials and Methods Design. Controlled, cross-sectional study. Sample. Meditators were recruited from a Zen Buddhist monastery. The control group was recruited from hospital staff. Meditators were administered questionnaires on anxiety, depression, cognitive impairment and mindfulness. 1H-MRS (1.5 T) of the brain was carried out by exploring four areas: both thalami, both hippocampi, the posterior superior parietal lobule (PSPL) and posterior cingulate gyrus. Predefined areas of the brain were measured for diffusivity (ADC) and fractional anisotropy (FA) by MR-DTI. Results Myo-inositol (mI) was increased in the posterior cingulate gyrus and Glutamate (Glu), N-acetyl-aspartate (NAA) and N-acetyl-aspartate/Creatine (NAA/Cr) was reduced in the left thalamus in meditators. We found a significant positive correlation between mI in the posterior cingulate and years of meditation (r = 0.518; p = .019). We also found significant negative correlations between Glu (r = −0.452; p = .045), NAA (r = −0.617; p = .003) and NAA/Cr (r = −0.448; P = .047) in the left thalamus and years of meditation. Meditators showed a lower Apparent Diffusion Coefficient (ADC) in the left posterior parietal white matter than did controls, and the ADC was negatively correlated with years of meditation (r = −0.4850, p = .0066). Conclusions The results are consistent with the view that mI, Glu and NAA are the most important altered metabolites. This study provides evidence of subtle abnormalities in neuronal function in regions of the white matter in meditators. PMID:23536796

  7. Acute necrotizing encephalopathy secondary to diphtheria, tetanus toxoid and whole-cell pertussis vaccination: diffusion-weighted imaging and proton MR spectroscopy findings

    International Nuclear Information System (INIS)

    Aydin, Hale; Ozgul, Esra; Agildere, Ahmet Muhtesem

    2010-01-01

    We present a previously healthy 6-month-old boy who was admitted to our hospital with lethargy, hypotonia and focal clonic seizures 6 days following diptheria, tetanus toxoid and whole-cell pertussis vaccination. A diagnosis of acute necrotising encephalopathy was made with the aid of MRI, including diffusion-weighted imaging and proton MR spectroscopy. (orig.)

  8. Acute necrotizing encephalopathy secondary to diphtheria, tetanus toxoid and whole-cell pertussis vaccination: diffusion-weighted imaging and proton MR spectroscopy findings

    Energy Technology Data Exchange (ETDEWEB)

    Aydin, Hale; Ozgul, Esra; Agildere, Ahmet Muhtesem [Baskent University Hospital, Department of Radiology, Ankara (Turkey)

    2010-07-15

    We present a previously healthy 6-month-old boy who was admitted to our hospital with lethargy, hypotonia and focal clonic seizures 6 days following diptheria, tetanus toxoid and whole-cell pertussis vaccination. A diagnosis of acute necrotising encephalopathy was made with the aid of MRI, including diffusion-weighted imaging and proton MR spectroscopy. (orig.)

  9. Correlations between Diffusion Tensor Imaging (DTI and Magnetic Resonance Spectroscopy (1H MRS in schizophrenic patients and normal controls

    Directory of Open Access Journals (Sweden)

    Ng Johnny

    2007-06-01

    Full Text Available Abstract Background Evidence suggests that white matter integrity may play an underlying pathophysiological role in schizophrenia. N-acetylaspartate (NAA, as measured by Magnetic Resonance Spectroscopy (MRS, is a neuronal marker and is decreased in white matter lesions and regions of axonal loss. It has also been found to be reduced in the prefrontal and temporal regions in patients with schizophrenia. Diffusion Tensor Imaging (DTI allows one to measure the orientations of axonal tracts as well as the coherence of axonal bundles. DTI is thus sensitive to demyelination and other structural abnormalities. DTI has also shown abnormalities in these regions. Methods MRS and DTI were obtained on 42 healthy subjects and 40 subjects with schizophrenia. The data was analyzed using regions of interests in the Dorso-Lateral Prefrontal white matter, Medial Temporal white matter and Occipital white matter using both imaging modalities. Results NAA was significantly reduced in the patient population in the Medial Temporal regions. DTI anisotropy indices were also reduced in the same Medial Temporal regions. NAA and DTI-anisotropy indices were also correlated in the left medial temporal region. Conclusion Our results implicate defects in the medial temporal white matter in patients with schizophrenia. Moreover, MRS and DTI are complementary modalities for the study of white matter disruptions in patients with schizophrenia.

  10. Correlated diffusion imaging

    International Nuclear Information System (INIS)

    Wong, Alexander; Glaister, Jeffrey; Cameron, Andrew; Haider, Masoom

    2013-01-01

    Prostate cancer is one of the leading causes of cancer death in the male population. Fortunately, the prognosis is excellent if detected at an early stage. Hence, the detection and localization of prostate cancer is crucial for diagnosis, as well as treatment via targeted focal therapy. New imaging techniques can potentially be invaluable tools for improving prostate cancer detection and localization. In this study, we introduce a new form of diffusion magnetic resonance imaging called correlated diffusion imaging, where the tissue being imaged is characterized by the joint correlation of diffusion signal attenuation across multiple gradient pulse strengths and timings. By taking into account signal attenuation at different water diffusion motion sensitivities, correlated diffusion imaging can provide improved delineation between cancerous tissue and healthy tissue when compared to existing diffusion imaging modalities. Quantitative evaluation using receiver operating characteristic (ROC) curve analysis, tissue class separability analysis, and visual assessment by an expert radiologist were performed to study correlated diffusion imaging for the task of prostate cancer diagnosis. These results are compared with that obtained using T2-weighted imaging and standard diffusion imaging (via the apparent diffusion coefficient (ADC)). Experimental results suggest that correlated diffusion imaging provide improved delineation between healthy and cancerous tissue and may have potential as a diagnostic tool for cancer detection and localization in the prostate gland. A new form of diffusion magnetic resonance imaging called correlated diffusion imaging (CDI) was developed for the purpose of aiding radiologists in cancer detection and localization in the prostate gland. Preliminary results show CDI shows considerable promise as a diagnostic aid for radiologists in the detection and localization of prostate cancer

  11. Diffusion-weighted imaging and magnetic resonance spectroscopy of sporadic Creutzfeldt-Jakob disease: correlation with clinical course

    International Nuclear Information System (INIS)

    Kim, Jae Hyoung; Choi, Byung Se; Jung, Cheolkyu; Chang, YoungHee; Kim, SangYun

    2011-01-01

    Sporadic Creutzfeldt-Jakob disease (sCJD) is a fatal disease with variable clinical courses. The presence or absence of basal ganglia (BG) involvement has been reported to be associated with clinical course. We investigated the association of clinical course of sCJD with diffusion-weighted imaging (DWI) and MR spectroscopy (MRS) as well as BG involvement at early stage. DWI and single voxel proton MRS were performed in 14 patients with sCJD during the initial diagnostic workup. Apparent diffusion coefficient (ADC) and metabolites were measured in medial occipitoparietal cortices where large hyperintense DWI lesions were found in all patients. The presence or absence of BG involvement, ADC, N-acetylaspartate (NAA)/creatine (Cr) ratios, and choline (Cho)/Cr ratios were correlated with disease duration (i.e., the time from the symptom onset to death). The disease duration ranged from 2 to 31 months (median, 16). Hyperintense DWI lesions were observed bilaterally in both cortices and basal ganglia in eight patients and in cortices alone in six patients. Patients with BG involvement had shorter disease duration (median, 6.8 versus 20.5; p = 0.039) than those without and lower NAA/Cr ratios (median, 1.41 versus 2.03; p = 0.001). ADC and Cho/Cr ratios were not significantly different between the patients with BG involvement and those without. By multiple regression analysis, NAA/Cr ratios had the greatest correlation with the disease duration (p = 0.029). The disease duration of sCJD was variable. NAA/Cr ratios of the affected brain at the early stage of sCJD can be used as a useful parameter in predicting the clinical course. (orig.)

  12. Diffusion-weighted imaging and magnetic resonance spectroscopy of sporadic Creutzfeldt-Jakob disease: correlation with clinical course

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Hyoung; Choi, Byung Se; Jung, Cheolkyu [Seoul National University Bundang Hospital, Department of Radiology, Seoul National University College of Medicine, Seongnam-si (Korea, Republic of); Chang, YoungHee; Kim, SangYun [Seoul National University Bundang Hospital, Department of Neurology, Seoul National University College of Medicine, Seongnam-si (Korea, Republic of)

    2011-12-15

    Sporadic Creutzfeldt-Jakob disease (sCJD) is a fatal disease with variable clinical courses. The presence or absence of basal ganglia (BG) involvement has been reported to be associated with clinical course. We investigated the association of clinical course of sCJD with diffusion-weighted imaging (DWI) and MR spectroscopy (MRS) as well as BG involvement at early stage. DWI and single voxel proton MRS were performed in 14 patients with sCJD during the initial diagnostic workup. Apparent diffusion coefficient (ADC) and metabolites were measured in medial occipitoparietal cortices where large hyperintense DWI lesions were found in all patients. The presence or absence of BG involvement, ADC, N-acetylaspartate (NAA)/creatine (Cr) ratios, and choline (Cho)/Cr ratios were correlated with disease duration (i.e., the time from the symptom onset to death). The disease duration ranged from 2 to 31 months (median, 16). Hyperintense DWI lesions were observed bilaterally in both cortices and basal ganglia in eight patients and in cortices alone in six patients. Patients with BG involvement had shorter disease duration (median, 6.8 versus 20.5; p = 0.039) than those without and lower NAA/Cr ratios (median, 1.41 versus 2.03; p = 0.001). ADC and Cho/Cr ratios were not significantly different between the patients with BG involvement and those without. By multiple regression analysis, NAA/Cr ratios had the greatest correlation with the disease duration (p = 0.029). The disease duration of sCJD was variable. NAA/Cr ratios of the affected brain at the early stage of sCJD can be used as a useful parameter in predicting the clinical course. (orig.)

  13. In the assessment of supratentorial glioma grade: The combined role of multivoxel proton MR spectroscopy and diffusion tensor imaging

    International Nuclear Information System (INIS)

    Zou, Q.-G.; Xu, H.-B.; Liu, F.; Guo, W.; Kong, X.-C.; Wu, Y.

    2011-01-01

    Aim: To detect a difference in the parameters derived from proton magnetic resonance spectroscopy ( 1 H-MRS) and diffusion tensor imaging (DTI) between low-grade and high-grade gliomas, and to evaluate whether the combination of these two techniques can improve the diagnostic accuracy of conventional magnetic resonance imaging (MRI) in supratentorial glioma grading. Materials and methods: Thirty patients with histologically proved supratentorial brain gliomas (12 low grade, 18 high grade) were prospectively evaluated with contrast material-enhanced MRI, DTI, and multivoxel 1 H-MRS (135 ms echo time). The tumour grades determined using the three methods were then compared with those obtained at histopathology. Receiver operating characteristic (ROC) analyses were performed to determine the optimum thresholds for glioma grading. Independent sample t-test, Spearman's rank correlation, and the Fisher's exact test were also carried out for statistical analysis. p -6 mm 2 /s for the calculated ADC value, corresponding to the maximum Youden index from the ROC curve of the above-selected parameters, the resultant sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs), and Kappa values were all higher and the fraction of misclassified tumour was lower when compared with conventional MRI. However, only NAA/Cho and ADC calculation contributed to the significant difference (p < 0.01) in the assessment of glioma grade compared to conventional MRI alone, and the grading results of statistical tests comparing those two parameters were highly consistent (kappa value = 0.798). Conclusion: Thresholds for NAA/Cho and calculated ADC values, corresponding to maximum Youden index from ROC curve analyses, helped to improve the accuracy of supratentorial glioma grading when compared with conventional MRI alone. In addition, a combination of NAA/Cho and ADC calculation were more useful together than each alone in a clinical setting to evaluate

  14. Fiber orientation measurements by diffusion tensor imaging improve hydrogen-1 magnetic resonance spectroscopy of intramyocellular lipids in human leg muscles.

    Science.gov (United States)

    Valaparla, Sunil K; Gao, Feng; Daniele, Giuseppe; Abdul-Ghani, Muhammad; Clarke, Geoffrey D

    2015-04-01

    Twelve healthy subjects underwent hydrogen-1 magnetic resonance spectroscopy ([Formula: see text]) acquisition ([Formula: see text]), diffusion tensor imaging (DTI) with a [Formula: see text]-value of [Formula: see text], and fat-water magnetic resonance imaging (MRI) using the Dixon method. Subject-specific muscle fiber orientation, derived from DTI, was used to estimate the lipid proton spectral chemical shift. Pennation angles were measured as 23.78 deg in vastus lateralis (VL), 17.06 deg in soleus (SO), and 8.49 deg in tibialis anterior (TA) resulting in a chemical shift between extramyocellular lipids (EMCL) and intramyocellular lipids (IMCL) of 0.15, 0.17, and 0.19 ppm, respectively. IMCL concentrations were [Formula: see text], [Formula: see text], and [Formula: see text] in SO, VL, and TA, respectively. Significant differences were observed in IMCL and EMCL pairwise comparisons in SO, VL, and TA ([Formula: see text]). Strong correlations were observed between total fat fractions from [Formula: see text] and Dixon MRI for VL ([Formula: see text]), SO ([Formula: see text]), and TA ([Formula: see text]). Bland-Altman analysis between fat fractions (FFMRS and FFMRI) showed good agreement with small limits of agreement (LoA): [Formula: see text] (LoA: [Formula: see text] to 0.69%) in VL, [Formula: see text] (LoA: [Formula: see text] to 1.33%) in SO, and [Formula: see text] (LoA: [Formula: see text] to 0.47%) in TA. The results of this study demonstrate the variation in muscle fiber orientation and lipid concentrations in these three skeletal muscle types.

  15. In the assessment of supratentorial glioma grade: The combined role of multivoxel proton MR spectroscopy and diffusion tensor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Q.-G. [Department of Neuroradiology, Union hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Xu, H.-B., E-mail: xuhaibo1120@hotmail.com [Department of Neuroradiology, Union hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Liu, F.; Guo, W. [Department of Neuroradiology, Union hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Kong, X.-C. [Department of Imaging technology, Union hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Wu, Y. [Department of Maternal and Child Health Care, Public Health School, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China)

    2011-10-15

    Aim: To detect a difference in the parameters derived from proton magnetic resonance spectroscopy ({sup 1}H-MRS) and diffusion tensor imaging (DTI) between low-grade and high-grade gliomas, and to evaluate whether the combination of these two techniques can improve the diagnostic accuracy of conventional magnetic resonance imaging (MRI) in supratentorial glioma grading. Materials and methods: Thirty patients with histologically proved supratentorial brain gliomas (12 low grade, 18 high grade) were prospectively evaluated with contrast material-enhanced MRI, DTI, and multivoxel {sup 1}H-MRS (135 ms echo time). The tumour grades determined using the three methods were then compared with those obtained at histopathology. Receiver operating characteristic (ROC) analyses were performed to determine the optimum thresholds for glioma grading. Independent sample t-test, Spearman's rank correlation, and the Fisher's exact test were also carried out for statistical analysis. p < 0.05 was considered statistically significant. Results: Statistically significant differences were found between the low-grade and high-grade gliomas for the choline (Cho)/creatine (Cr), N-acetylaspartate (NAA)/Cr, NAA/Cho ratio in the tumours (p < 0.01), apparent diffusion coefficient (ADC) value (p < 0.01), and fractional anisotropy (FA) value (p < 0.05) in the tumours. The NAA/Cr and NAA/Cho ratios and the calculated ADC value significantly correlated with the histological grading of the gliomas (p < 0.01). Using a threshold value of 0.66 for tumour NAA/Cr, 0.265 for NAA/Cho, 1118.1 x 10{sup -6} mm{sup 2}/s for the calculated ADC value, corresponding to the maximum Youden index from the ROC curve of the above-selected parameters, the resultant sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs), and Kappa values were all higher and the fraction of misclassified tumour was lower when compared with conventional MRI. However, only NAA/Cho and

  16. Minimal hepatic encephalopathy in children with liver cirrhosis: diffusion-weighted MR imaging and proton MR spectroscopy of the brain

    Energy Technology Data Exchange (ETDEWEB)

    Abdel Razek, Ahmed Abdel Khalek; Ezzat, Amany [Mansoura University Hospital, Department of Diagnostic Radiology, Mansoura Faculty of Medicine, Mansoura (Egypt); Abdalla, Ahmed; Megahed, Ahmed; Barakat, Tarek [Mansoura Children Hospital, Gastroenterology and Hepatology Unit, Mansoura Faculty of Medicine, Mansoura (Egypt)

    2014-10-15

    The aim of this work was to detect minimal hepatic encephalopathy (minHE) in children with diffusion-weighted MR imaging (DWI) and proton magnetic resonance spectroscopy ({sup 1}H-MRS) of the brain. Prospective study conducted upon 30 consecutive children (age range 6-16 years, 21 boys and 9 girls) with liver cirrhosis and 15 age- and sex-matched healthy control children. Patients with minHE (n = 17) and with no minHE (n = 13) groups and control group underwent DWI, {sup 1}H-MRS, and neuropsychological tests (NPTs). The glutamate or glutamine (Glx), myoinositol (mI), choline (Cho), and creatine (Cr) at the right ganglionic region were determined at {sup 1}H-MRS. The apparent diffusion coefficient (ADC) value and metabolic ratios of Glx/Cr, mI/Cr, and Cho/Cr were calculated. There was elevated ADC value and Glx/Cr and decreased mI/CI and Ch/Cr in patients with minHE compared to no minHE and control group. There was significant difference between minHE, no minHE, and control group in the ADC value (P = 0.001 for all groups), GLx/Cr (P = 0.001 for all groups), mI/Cr (P = 0.004, 0.001, and 0.001, respectively), Ch/Cr (P = 0.001 for all groups), and full-scale IQ of NPT (P = 0.001, 0.001, and 0.143, respectively). The NPT of minHE had negative correlation with ADC value (r = -0.872, P = 0.001) and GLx/Cr (r = -0.812, P = 0.001) and positive correlation with mI/Cr (r = 0.732, P = 0.001). DWI and {sup 1}H-MRS are imaging modalities that can detect minHE in children with liver cirrhosis and correlate well with parameters of NPT. (orig.)

  17. Minimal hepatic encephalopathy in children with liver cirrhosis: diffusion-weighted MR imaging and proton MR spectroscopy of the brain

    International Nuclear Information System (INIS)

    Abdel Razek, Ahmed Abdel Khalek; Ezzat, Amany; Abdalla, Ahmed; Megahed, Ahmed; Barakat, Tarek

    2014-01-01

    The aim of this work was to detect minimal hepatic encephalopathy (minHE) in children with diffusion-weighted MR imaging (DWI) and proton magnetic resonance spectroscopy ( 1 H-MRS) of the brain. Prospective study conducted upon 30 consecutive children (age range 6-16 years, 21 boys and 9 girls) with liver cirrhosis and 15 age- and sex-matched healthy control children. Patients with minHE (n = 17) and with no minHE (n = 13) groups and control group underwent DWI, 1 H-MRS, and neuropsychological tests (NPTs). The glutamate or glutamine (Glx), myoinositol (mI), choline (Cho), and creatine (Cr) at the right ganglionic region were determined at 1 H-MRS. The apparent diffusion coefficient (ADC) value and metabolic ratios of Glx/Cr, mI/Cr, and Cho/Cr were calculated. There was elevated ADC value and Glx/Cr and decreased mI/CI and Ch/Cr in patients with minHE compared to no minHE and control group. There was significant difference between minHE, no minHE, and control group in the ADC value (P = 0.001 for all groups), GLx/Cr (P = 0.001 for all groups), mI/Cr (P = 0.004, 0.001, and 0.001, respectively), Ch/Cr (P = 0.001 for all groups), and full-scale IQ of NPT (P = 0.001, 0.001, and 0.143, respectively). The NPT of minHE had negative correlation with ADC value (r = -0.872, P = 0.001) and GLx/Cr (r = -0.812, P = 0.001) and positive correlation with mI/Cr (r = 0.732, P = 0.001). DWI and 1 H-MRS are imaging modalities that can detect minHE in children with liver cirrhosis and correlate well with parameters of NPT. (orig.)

  18. Multimodal MRI in the characterization of glial neoplasms: the combined role of single-voxel MR spectroscopy, diffusion imaging and echo-planar perfusion imaging

    International Nuclear Information System (INIS)

    Zonari, Paolo; Baraldi, Patrizia; Crisi, Girolamo

    2007-01-01

    Diffusion-weighted imaging (DWI), perfusion-weighted imaging (PWI) and MR spectroscopy (MRS) provide useful data for tumor evaluation. To assess the contribution of these multimodal techniques in grading glial neoplasms, we compared the value of DWI, PWI and MRS in the evaluation of histologically proven high- and low-grade gliomas in a population of 105 patients. Independently for each modality, the following variables were used to compare the tumors: minimum apparent diffusion coefficient (ADC) and maximum relative cerebral blood volume (rCBV) normalized values between tumor and healthy tissue, maximum Cho/Cr ratio and minimum NAA/Cr ratio in tumor, and scored lactate and lipid values in tumor. The Mann-Whitney and Wilcoxon tests were employed to compare DWI, PWI and MRS between tumor types. Logistic regression analysis was used to determine which parameters best increased the diagnostic accuracy in terms of sensitivity, specificity, and positive and negative predictive values. ROC curves were determined for parameters with high sensitivity and specificity to identify threshold values to separate high- from low-grade lesions. Statistically significant differences were found for rCBV tumor/normal tissue ratio, and NAA/Cr ratio in tumor and Cho/Cr ratio in tumor between low- and high-grade tumors. The best performing single parameter for group classification was the normalized rCBV value; including all parameters, statistical significance was reached by rCBV tumor/normal tissue ratio, NAA/Cr tumor ratio and lactate. From the ROC curves, a high probability for a neoplasm to be a high-grade lesion was associated with a rCBV tumor/normal tissue ratio of >1.16 and NAA/Cr tumor ratio of <0.44. Combining PWI and MRS with conventional MR imaging increases the accuracy of the attribution of malignancy to glial neoplasms. The best performing parameter was found to be the perfusion level. (orig.)

  19. 1H-MR spectroscopy and diffusion tensor imaging of normal-appearing temporal white matter in patients with nasopharyngeal carcinoma after irradiation: initial experience.

    Science.gov (United States)

    Xiong, Wei Feng; Qiu, Shi Jun; Wang, Hong Zhuo; Lv, Xiao Fei

    2013-01-01

    To detect radiation-induced changes of temporal lobe normal-appearing white mater (NAWM) following radiation therapy (RT) for nasopharyngeal carcinoma (NPC). Seventy-five H(1)-MR spectroscopy and diffusion-tensor imaging (DTI) examinations were performed in 55 patients before and after receiving fractionated radiation therapy (total dose; 66-75GY). We divided the dataset into six groups, a pre-RT control group and five other groups based on time after completion of RT. N-acetylaspartic acid (NAA)/choline (Cho), NAA/creatine (Cr), Cho/Cr, mean diffusibility (MD), functional anisotropy (FA), radial diffusibility (λ(⊥)), and axial diffusibility (λ(||)) were calculated. NAA/Cho and NAA/Cr decreased and λ(⊥) increased significantly within 1 year after RT compared with pre-RT. After 1 year, NAA/Cho, NAA/Cr, and λ(⊥) were not significantly different from pre-RT. In all post-RT groups, FA decreased significantly. λ(||) decreased within 9 months after RT compared with pre-RT, but was not significantly different from pre-RT more than 9 months after RT. DTI and H(1)-MR spectroscopy can be used to detect early radiation-induced changes of temporal lobe NAWM following radiation therapy for NPC. Metabolic alterations and water diffusion characteristics of temporal lobe NAWM in patients with NPC after RT were dynamic and transient. Copyright © 2012 Wiley Periodicals, Inc.

  20. Differentiating between axonal damage and demyelination in healthy aging by combining diffusion-tensor imaging and diffusion-weighted spectroscopy in the human corpus callosum at 7 T.

    Science.gov (United States)

    Branzoli, Francesca; Ercan, Ece; Valabrègue, Romain; Wood, Emily T; Buijs, Mathijs; Webb, Andrew; Ronen, Itamar

    2016-11-01

    Diffusion-tensor imaging and single voxel diffusion-weighted magnetic resonance spectroscopy were used at 7T to explore in vivo age-related microstructural changes in the corpus callosum. Sixteen healthy elderly (age range 60-71 years) and 13 healthy younger controls (age range 23-32 years) were included in the study. In healthy elderly, we found lower water fractional anisotropy and higher water mean diffusivity and radial diffusivity in the corpus callosum, indicating the onset of demyelination processes with healthy aging. These changes were not associated with a concomitant significant difference in the cytosolic diffusivity of the intra-axonal metabolite N-acetylaspartate (p = 0.12), the latter representing a pure measure of intra-axonal integrity. It was concluded that the possible intra-axonal changes associated with normal aging processes are below the detection level of diffusion-weighted magnetic resonance spectroscopy in our experiment (e.g., smaller than 10%) in the age range investigated. Lower axial diffusivity of total creatine was observed in the elderly group (p = 0.058), possibly linked to a dysfunction in the energy metabolism associated with a deficit in myelin synthesis. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Comparison of diffusion tensor imaging and proton MR spectroscopy in the posterior cingulate of patients with Alzheimer disease

    International Nuclear Information System (INIS)

    Ding Bei; Ling Huawei; Zhang Hua; Chai Weimin; Chen Kemin; Li Xia; Wang Tao

    2009-01-01

    Objective To compare 1 HMRS and DTI findings of Alzheimer disease (AD) patients and normal elderly controls. Methods: Fifteen mild AD patients, 20 moderate to severe AD patients and 20 aging controlled normal subjects (CN) were recruited. MRS imaging and DTI were performed on a 1.5 T MRI scanner. A ROI was positioned in the posterior part of the cingulate. MRS data were processed and the metabolite ratios were estimated, including the ratios of NAA/Cr, Cho/Cr, mI/Cr. Comparing with the axial MRS location, we chose the same level to posit the ROIs on both sides of the posterior cingulated fibers on fractional anisotropy map (FA) and mean diffusivity map (MD). Mean spectroscopy data and DTI values for each groups were analysed with Mann-Whitney U non parametric test. Correlations between MRS and DTI values for AD groups were estimated using partial correlations test controlling for the age related bias. Results Compared to normal aging groups, mild AD group showed a significantly lower FA value in the left side of posterior cingulum bundle (0.549±0.056 vs 0.517±0.058, Z=2.014, P -3 mm 2 /s vs (0.761±0.057) x 10 -3 mm 2 /s, Z=1.970, P<0.05). Obvious increasing mI/Cr ratio was found in mild AD group(0.61±0.07 vs 0.68±0.12,Z=2.911, P<0.01). NAA/Cr ratio showed gradually decrease in AD groups. Partial correlations analysis revealed a positive correlation between mI/Cr ratio and left posterior cingulated FA value in mild AD group (r=0.586, P< 0.05) and negative correlation between NAA/Cr and MD value in the right side of posterior cingulated region (r=-0.505, P<0.05). Conclusions: These findings suggested that there were different regional and temporal pattern in different course of AD disease, resulting from axonal loss or gliosis. Combining MRS with DTI alternations could be a better potential indicator and could better explain the pathological changes in AD progression. (authors)

  2. Potential long-term effects of MDMA on the basal ganglia-thalamocortical circuit: a proton MR spectroscopy and diffusion-tensor imaging study.

    Science.gov (United States)

    Liu, Hua-Shan; Chou, Ming-Chung; Chung, Hsiao-Wen; Cho, Nai-Yu; Chiang, Shih-Wei; Wang, Chao-Ying; Kao, Hung-Wen; Huang, Guo-Shu; Chen, Cheng-Yu

    2011-08-01

    To investigate the effects of 3,4-methylenedioxymethamphetamine (MDMA, commonly known as "ecstasy") on the alterations of brain metabolites and anatomic tissue integrity related to the function of the basal ganglia-thalamocortical circuit by using proton magnetic resonance (MR) spectroscopy and diffusion-tensor MR imaging. This study was approved by a local institutional review board, and written informed consent was obtained from all subjects. Thirty-one long-term (>1 year) MDMA users and 33 healthy subjects were enrolled. Proton MR spectroscopy from the middle frontal cortex and bilateral basal ganglia and whole-brain diffusion-tensor MR imaging were performed with a 3.0-T system. Absolute concentrations of metabolites were computed, and diffusion-tensor data were registered to the International Consortium for Brain Mapping template to facilitate voxel-based group comparison. The mean myo-inositol level in the basal ganglia of MDMA users (left: 4.55 mmol/L ± 2.01 [standard deviation], right: 4.48 mmol/L ± 1.33) was significantly higher than that in control subjects (left: 3.25 mmol/L ± 1.30, right: 3.31 mmol/L ± 1.19) (P 50 voxels). Increased myo-inositol and Cho concentrations in the basal ganglia of MDMA users are suggestive of glial response to degenerating serotonergic functions. The abnormal metabolic changes in the basal ganglia may consequently affect the inhibitory effect of the basal ganglia to the thalamus, as suggested by the increased FA in the thalamus and abnormal changes in water diffusion in the corresponding basal ganglia-thalamocortical circuit. © RSNA, 2011.

  3. Scanning, non-contact, hybrid broadband diffuse optical spectroscopy and diffuse correlation spectroscopy system.

    Science.gov (United States)

    Johansson, Johannes D; Mireles, Miguel; Morales-Dalmau, Jordi; Farzam, Parisa; Martínez-Lozano, Mar; Casanovas, Oriol; Durduran, Turgut

    2016-02-01

    A scanning system for small animal imaging using non-contact, hybrid broadband diffuse optical spectroscopy (ncDOS) and diffuse correlation spectroscopy (ncDCS) is presented. The ncDOS uses a two-dimensional spectrophotometer retrieving broadband (610-900 nm) spectral information from up to fifty-seven source-detector distances between 2 and 5 mm. The ncDCS data is simultaneously acquired from four source-detector pairs. The sample is scanned in two dimensions while tracking variations in height. The system has been validated with liquid phantoms, demonstrated in vivo on a human fingertip during an arm cuff occlusion and on a group of mice with xenoimplanted renal cell carcinoma.

  4. Analysis of the human brain in primary progressive multiple sclerosis with mapping of the spatial distributions using 1H MR spectroscopy and diffusion tensor imaging

    International Nuclear Information System (INIS)

    Sijens, Paul E.; Irwan, Roy; Potze, Jan Hendrik; Oudkerk, Matthijs; Mostert, Jop P.; Keyser, Jacques de

    2005-01-01

    Primary progressive multiple sclerosis (ppMS; n=4) patients and controls (n=4) were examined by 1H magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI) in order to map choline (Cho), creatine and N-acetylaspartate (NAA), the fractional anisotropy (FA) and the apparent diffusion constant (ADC). After chemical shift imaging (point-resolved spectroscopy, repetition time/echo time 1,500 ms/135 ms) of a supraventricular volume of interest of 8 x 8 x 2 cm 3 (64 voxels) MRS peak areas were matched to the results of DTI for the corresponding volume elements. Mean FA and NAA values were reduced in the ppMS patients (P<0.01, both) and the ADC increased (P<0.02). The spatial distribution of NAA showed strong correlation to ADC in both ppMS patients and controls (r =-0.74 and r= -0.70; P<0.00001, both), and weaker correlations to FA (r=0.49 and r=0.41; P<0.00001, all). FA and ADC also correlated significantly with Cho in patients and controls (P<0.00001, all). The relationship of Cho and NAA to the ADC and the FA and thus to the content of neuronal structures suggests that these metabolite signals essentially originate from axons (NAA) and the myelin sheath (Cho). This is of interest in view of previous reports in which Cho increases were associated with demyelination and the subsequent breakdown of neurons. (orig.)

  5. In vivo P-31 MR diffusion spectroscopy

    International Nuclear Information System (INIS)

    Moonen, C.T.W.; Vanzijl, P.C.M.; LeBihan, D.

    1988-01-01

    This paper discusses the Stejskal-Tanner diffusion spin-echo sequence modified for the in vivo diffusion spectroscopy. The apparent diffusion constant D α was measured as a function of the diffusion time. Contrary to the results in phantom samples, a strong dependency of the D α for phosphocreatine (PCr) in the rat muscle tissue on diffusion time was observed, clearly indicating restricted diffusion effects and allowing an approximation of the size of the restricted volume (8-13 μm). This size fits well with the known dimensions of a normal muscle cell

  6. Everyman's prostate phantom: kiwi-fruit substitute for human prostates at magnetic resonance imaging, diffusion-weighted imaging and magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mueller-Lisse, Ullrich G.; Murer, Sophie; Kuhn, Marissa [University of Munich (' ' Ludwig-Maximilians-Universitaet' ' , LMU), Department of Radiology, Faculty of Medicine, Muenchen (Germany); Mueller-Lisse, Ulrike L. [University of Munich (' ' Ludwig-Maximilians-Universitaet' ' , LMU), Department of Urology, Faculty of Medicine, Muenchen (Germany); Interdisciplinary Oncology Centre Munich (IOZ), Department of Urology, Munich (Germany); Scheidler, Juergen [University of Munich (' ' Ludwig-Maximilians-Universitaet' ' , LMU), Department of Radiology, Faculty of Medicine, Muenchen (Germany); Radiology Centre Munich (RZM), Muenchen (Germany); Scherr, Michael [University of Munich (' ' Ludwig-Maximilians-Universitaet' ' , LMU), Department of Radiology, Faculty of Medicine, Muenchen (Germany); BG Unfallklinik Murnau, Department of Radiology, Murnau am Staffelsee (Germany)

    2017-08-15

    To apply an easy-to-assemble phantom substitute for human prostates in T2-weighted magnetic resonance imaging (T2WI), diffusion-weighted imaging (DWI) and 3D magnetic resonance spectroscopy (MRS). Kiwi fruit were fixed with gel hot and cold compress packs on two plastic nursery pots, separated by a plastic plate, and submerged in tap water inside a 1-L open-spout plastic watering can for T2WI (TR/TE 7500/101 ms), DWI (5500/61 ms, ADC b50-800 s/mm{sup 2} map) and MRS (940/145 ms) at 3.0 T, with phased array surface coils. One green kiwi fruit was additionally examined with an endorectal coil. Retrospective comparison with benign peripheral zone (PZ) and transitional zone (TZ) of prostate (n = 5), Gleason 6-7a prostate cancer (n = 8) and Gleason 7b-9 prostate cancer (n = 7) validated the phantom. Mean contrast between central placenta (CP) and outer pericarp (OP, 0.346-0.349) or peripheral placenta (PP, 0.364-0.393) of kiwi fruit was similar to Gleason 7b-9 prostate cancer and PZ (0.308) in T2WI. ADC values of OP and PP (1.27 ± 0.07-1.37 ± 0.08 mm{sup 2}/s x 10{sup -3}) resembled PZ and TZ (1.39 ± 0.17-1.60 ± 0.24 mm{sup 2}/s x 10{sup -3}), while CP (0.91 ± 0.14-0.99 ± 0.10 mm{sup 2}/s x 10{sup -3}) resembled Gleason 7b-9 prostate cancer (1.00 ± 0.25 mm{sup 2}/s x 10{sup -3}). MR spectra showed peaks of citrate and myo-inositol in kiwi fruit, and citrate and ''choline+creatine'' in prostates. The phantom worked with an endorectal coil, too. The kiwi fruit phantom reproducibly showed zones similar to PZ, TZ and cancer in human prostates in T2WI and DWI and two metabolite peaks in MRS and appears suitable to compare different MR protocols, coil systems and scanners. (orig.)

  7. Prognostic value of brain proton MR spectroscopy and diffusion tensor imaging in newborns with hypoxic-ischemic encephalopathy treated by brain cooling

    Energy Technology Data Exchange (ETDEWEB)

    Ancora, G. [Neonatal Intensive Care Unit, Department of Mother and Infant Infermi Hospital of Rimini, Rimini (Italy); Testa, C.; Tonon, C.; Manners, D.N.; Gramegna, L.L.; Lodi, R. [Department of Biomedical and Neuromotor Sciences University of Bologna, MR Functional Unit, Bologna (Italy); Grandi, S.; Sbravati, F.; Savini, S.; Corvaglia, L.T.; Faldella, G. [University of Bologna, Neonatology Unit, Department of Woman, Child and Adolescent Health, Bologna (Italy); Tani, G. [University of Bologna, Radiology Unit, Department of Woman, Child and Adolescent Health, Bologna (Italy); Malucelli, E. [University of Bologna, Department of Pharmacy and Biotechnologies, Bologna (Italy)

    2013-08-15

    MRI, proton magnetic resonance spectroscopy ({sup 1}H-MRS), and diffusion tensor imaging (DTI) have been shown to be of great prognostic value in term newborns with moderate-severe hypoxic-ischemic encephalopathy (HIE). Currently, no data are available on {sup 1}H-MRS and DTI performed in the subacute phase after hypothermic treatment. The aim of the present study was to assess their prognostic value in newborns affected by moderate-severe HIE and treated with selective brain cooling (BC). Twenty infants treated with BC underwent conventional MRI and {sup 1}H-MRS at a mean (SD) age of 8.3 (2.8) days; 15 also underwent DTI. Peak area ratios of metabolites and DTI variables, namely mean diffusivity (MD), axial and radial diffusivity, and fractional anisotropy (FA), were calculated. Clinical outcome was monitored until 2 years of age. Adverse outcome was observed in 6/20 newborns. Both {sup 1}H-MRS and DTI variables showed higher prognostic accuracy than conventional MRI. N-acetylaspartate/creatine at a basal ganglia localisation showed 100 % PPV and 93 % NPV for outcome. MD showed significantly decreased values in many regions of white and gray matter, axial diffusivity showed the best predictive value (PPV and NPV) in the genu of corpus callosum (100 and 91 %, respectively), and radial diffusivity was significantly decreased in fronto white matter (FWM) and fronto parietal (FP) WM. The decrement of FA showed the best AUC (0.94) in the FPWM. Selective BC in HIE neonates does not affect the early and accurate prognostic value of {sup 1}H-MRS and DTI, which outperform conventional MRI. (orig.)

  8. Prognostic value of brain proton MR spectroscopy and diffusion tensor imaging in newborns with hypoxic-ischemic encephalopathy treated by brain cooling

    International Nuclear Information System (INIS)

    Ancora, G.; Testa, C.; Tonon, C.; Manners, D.N.; Gramegna, L.L.; Lodi, R.; Grandi, S.; Sbravati, F.; Savini, S.; Corvaglia, L.T.; Faldella, G.; Tani, G.; Malucelli, E.

    2013-01-01

    MRI, proton magnetic resonance spectroscopy ( 1 H-MRS), and diffusion tensor imaging (DTI) have been shown to be of great prognostic value in term newborns with moderate-severe hypoxic-ischemic encephalopathy (HIE). Currently, no data are available on 1 H-MRS and DTI performed in the subacute phase after hypothermic treatment. The aim of the present study was to assess their prognostic value in newborns affected by moderate-severe HIE and treated with selective brain cooling (BC). Twenty infants treated with BC underwent conventional MRI and 1 H-MRS at a mean (SD) age of 8.3 (2.8) days; 15 also underwent DTI. Peak area ratios of metabolites and DTI variables, namely mean diffusivity (MD), axial and radial diffusivity, and fractional anisotropy (FA), were calculated. Clinical outcome was monitored until 2 years of age. Adverse outcome was observed in 6/20 newborns. Both 1 H-MRS and DTI variables showed higher prognostic accuracy than conventional MRI. N-acetylaspartate/creatine at a basal ganglia localisation showed 100 % PPV and 93 % NPV for outcome. MD showed significantly decreased values in many regions of white and gray matter, axial diffusivity showed the best predictive value (PPV and NPV) in the genu of corpus callosum (100 and 91 %, respectively), and radial diffusivity was significantly decreased in fronto white matter (FWM) and fronto parietal (FP) WM. The decrement of FA showed the best AUC (0.94) in the FPWM. Selective BC in HIE neonates does not affect the early and accurate prognostic value of 1 H-MRS and DTI, which outperform conventional MRI. (orig.)

  9. Primary granulomatous angiitis of the central nervous system: findings of magnetic resonance spectroscopy and fractional anisotropy in diffusion tensor imaging prior to surgery. Case report.

    Science.gov (United States)

    Beppu, Takaaki; Inoue, Takashi; Nishimoto, Hideaki; Nakamura, Shinichi; Nakazato, Yoichi; Ogasawara, Kuniaki; Ogawa, Akira

    2007-10-01

    Primary granulomatous angiitis of the central nervous system (CNS) is extremely rare. Its preoperative diagnosis is difficult as the condition displays nonspecific features on routine neuroimaging investigations. In this paper, the authors report findings of magnetic resonance (MR) spectroscopy and fractional anisotropy (FA) with diffusion tensor MR imaging in a case of granulomatous angiitis of the CNS. A 30-year-old man presented with morning headaches and grand mal seizures. An MR image revealed a mass resembling glioblastoma in the right temporal lobe. Magnetic resonance spectroscopy showed a high choline/creatine (Cho/Cr) ratio indicative of a malignant neoplasm, accompanied by a slight elevation of glutamate and glutamine. The FA value was very low, which is inconsistent with malignant glioma. The mass was totally removed surgically. Histologically, the peripheral lesion of the mass consisted of a rough accumulation of fat granule cells, infiltration of inflammatory cells, and distribution of capillary vessels. Some vessels within the lesion were replaced by granulomas. The histological diagnosis was granulomatous angiitis of the CNS. The MIB-1-positive rate of the granuloma was approximately 5%. Both MR spectroscopy and FA were unable to accurately diagnose granulomatous angiitis of the CNS prior to surgery; however, elevated Cho/Cr and glutamate and glutamine shown by MR spectroscopy may indicate the moderate proliferation potential of the granuloma and the inflammatory process, respectively, in this condition. Although the low FA value in the present case enabled the authors to rule out a diagnosis of glioblastoma, FA values in inflammatory lesions require careful interpretation.

  10. Study of white matter at the centrum semiovale level with magnetic resonance spectroscopy and diffusion tensor imaging in cerebral small vessel disease.

    Science.gov (United States)

    Huang, L A; Ling, X Y; Li, C; Zhang, S J; Chi, G B; Xu, A D

    2014-04-08

    White matter lesion (WML) in magnetic resonance imaging is commonly observed in patients with cerebral small vessel disease (SVD), but the pathological mechanism of WML in SVD is still unclear. We observed the metabolism and microscopic anatomy of white matter in SVD patients. Twelve subjects clinically diagnosed with SVD and 6 normal control subjects were examined with magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI). The white matter at the centrum semiovale level was selected as the region of interest (ROI). The ROI metabolism parameters, including N-acetyl-l-aspartic acid (NAA), creatine (Cr), and choline (Cho) were measured by MRS. Microscopic parameters such as mean diffusion (MD) and fractional anisotropy (FA) in ROI were obtained by DTI. Compared with the normal control group, bilateral MD values in the SVD group were significantly elevated, whereas bilateral FA values in SVD were decreased, but the difference was not statistically significant. Additionally, NAA/Cho, Cho/Cr, and NAA/Cr showed no significant statistical differences. Our study suggests that the mechanisms of the SVD cognitive impairment are related to damage of the white matter structures rather than to brain metabolism.

  11. Noninvasive monitoring of radiation-induced treatment response using proton magnetic resonance spectroscopy and diffusion-weighted magnetic resonance imaging in a colorectal tumor model

    International Nuclear Information System (INIS)

    Seierstad, Therese; Roe, Kathrine; Olsen, Dag Rune

    2007-01-01

    Background and purpose: To examine whether in vivo proton magnetic resonance spectroscopy ( 1 H MRS) and diffusion-weighted magnetic resonance imaging (DW-MRI) can monitor radiation-induced changes in HT29 xenografts in mice. Materials and methods: HT29 xenografts in mice received a dose of 15 Gy. In vivo 1 H MRS and DW-MRI were acquired pretreatment and 1, 3, 6 and 10 days post-irradiation. After imaging, tumors were excised for histological analysis. The amounts of necrosis, fibrosis and viable cells in the cross sections were scored and compared to changes in apparent diffusion coefficient (ADC) and choline/water ratio. Results: Radiation-induced necrosis in the xenografts was observed as increased tumor ADC. In-growth of fibrosis three days post-irradiation restricting water mobility was accompanied by decreased tumor ADC. Choline/water ratio correlated with metabolic activity and tumor growth. Conclusions: ADC and choline/water ratio assessed by in vivo DW-MRI and 1 H MRS depicts radiation-induced changes in HT29 xenografts following irradiation

  12. Optical imaging and spectroscopy

    CERN Document Server

    Brady, David J

    2009-01-01

    An essential reference for optical sensor system design This is the first text to present an integrated view of the optical and mathematical analysis tools necessary to understand computational optical system design. It presents the foundations of computational optical sensor design with a focus entirely on digital imaging and spectroscopy. It systematically covers: Coded aperture and tomographic imaging Sampling and transformations in optical systems, including wavelets and generalized sampling techniques essential to digital system analysis Geometric, wave, and statis

  13. Advanced MRI increases the diagnostic accuracy of recurrent glioblastoma: Single institution thresholds and validation of MR spectroscopy and diffusion weighted MR imaging

    Directory of Open Access Journals (Sweden)

    Tomas Kazda

    2016-01-01

    Full Text Available The accurate identification of glioblastoma progression remains an unmet clinical need. The aim of this prospective single-institutional study is to determine and validate thresholds for the main metabolite concentrations obtained by MR spectroscopy (MRS and the values of the apparent diffusion coefficient (ADC to enable distinguishing tumor recurrence from pseudoprogression. Thirty-nine patients after the standard treatment of a glioblastoma underwent advanced imaging by MRS and ADC at the time of suspected recurrence — median time to progression was 6.7 months. The highest significant sensitivity and specificity to call the glioblastoma recurrence was observed for the total choline (tCho to total N-acetylaspartate (tNAA concentration ratio with the threshold ≥1.3 (sensitivity 100.0% and specificity 94.7%. The ADCmean value higher than 1313 × 10−6 mm2/s was associated with the pseudoprogression (sensitivity 98.3%, specificity 100.0%. The combination of MRS focused on the tCho/tNAA concentration ratio and the ADCmean value represents imaging methods applicable to early non-invasive differentiation between a glioblastoma recurrence and a pseudoprogression. However, the institutional definition and validation of thresholds for differential diagnostics is needed for the elimination of setup errors before implementation of these multimodal imaging techniques into clinical practice, as well as into clinical trials.

  14. Competition between convection and diffusion in a metal halide lamp, investigated by numerical simulations and imaging laser absorption spectroscopy

    NARCIS (Netherlands)

    Beks, M.L.; Flikweert, A.J.; Nimalasuriya, T.; Stoffels, W.W.; Mullen, van der J.J.A.M.

    2008-01-01

    The effect of the competition between convection and diffusion on the distribution of metal halide additives in a high pressure mercury lamp has been examined by placing COST reference lamps with mercury fillings of 5 and 10 mg in a centrifuge. By subjecting them to different accelerational

  15. Early detection of ventilation-induced brain injury using magnetic resonance spectroscopy and diffusion tensor imaging: an in vivo study in preterm lambs.

    Directory of Open Access Journals (Sweden)

    Béatrice Skiöld

    Full Text Available BACKGROUND AND AIM: High tidal volume (VT ventilation during resuscitation of preterm lambs results in brain injury evident histologically within hours after birth. We aimed to investigate whether magnetic resonance spectroscopy (MRS and/or diffusion tensor imaging (DTI can be used for early in vivo detection of ventilation-induced brain injury in preterm lambs. METHODS: Newborn lambs (0.85 gestation were stabilized with a "protective ventilation" strategy (PROT, n = 7: prophylactic Curosurf, sustained inflation, VT 7 mL/kg, positive end expiratory pressure (PEEP 5 cmH2O or an initial 15 minutes of "injurious ventilation" (INJ, n = 10: VT 12 mL/kg, no PEEP, late Curosurf followed by PROT ventilation for the remainder of the experiment. At 1 hour, lambs underwent structural magnetic resonance imaging (Siemens, 3 Tesla. For measures of mean/axial/radial diffusivity (MD, AD, RD and fractional anisotropy (FA, 30 direction DTI was performed. Regions of interests encompassed the thalamus, internal capsule, periventricular white matter and the cerebellar vermis. MRS was performed using a localized single-voxel (15×15×20 mm3, echo time 270 ms encompassing suptratentorial deep nuclear grey matter and central white matter. Peak-area ratios for lactate (Lac relative to N-acetylaspartate (NAA, choline (Cho and creatine (Cr were calculated. Groups were compared using 2-way RM-ANOVA, Mann-Whitney U-test and Spearman's correlations. RESULTS: No cerebral injury was seen on structural MR images. Lambs in the INJ group had higher mean FA and lower mean RD in the thalamus compared to PROT lambs, but not in the other regions of interest. Peak-area lactate ratios >1.0 was only seen in INJ lambs. A trend of higher mean peak-area ratios for Lac/Cr and Lac/Cho was seen, which correlated with lower pH in both groups. CONCLUSION: Acute changes in brain diffusion measures and metabolite peak-area ratios were observed after injurious ventilation. Early MRS/DTI is

  16. New MR sequences (diffusion, perfusion, spectroscopy) in brain tumours

    International Nuclear Information System (INIS)

    Rossi, Andrea; Gandolfo, Carlo; Morana, Giovanni; Severino, Mariasavina; Garre, Maria Luisa; Cama, Armando

    2010-01-01

    While MRI has been instrumental in significantly improving care in children harbouring brain tumours, conventional sequences lack information regarding functional parameters including cellularity, haemodynamics and metabolism. Advanced MR imaging modalities, such as diffusion (including diffusion tensor imaging and fibre tractography), perfusion and spectroscopy have significantly improved our understanding of the physiopathology of brain tumours and have provided invaluable additional information for treatment planning and monitoring of treatment results. The contribution of these methods to the characterization of brain neoplasms in children is the focus of the present manuscript. (orig.)

  17. Diffusion properties of NAA in human corpus callosum as studied with diffusion tensor spectroscopy.

    Science.gov (United States)

    Upadhyay, Jaymin; Hallock, Kevin; Erb, Kelley; Kim, Dae-Shik; Ronen, Itamar

    2007-11-01

    In diffusion tensor imaging (DTI) the anisotropic movement of water is exploited to characterize microstructure. One confounding issue of DTI is the presence of intra- and extracellular components contributing to the measured diffusivity. This causes an ambiguity in determining the underlying cause of diffusion properties, particularly the fractional anisotropy (FA). In this study an intracellular constituent, N-acetyl aspartate (NAA), was used to probe intracellular diffusion, while water molecules were used to probe the combined intra- and extracellular diffusion. NAA and water diffusion measurements were made in anterior and medial corpus callosum (CC) regions, which are referred to as R1 and R2, respectively. FA(NAA) was found to be greater than FA(Water) in both CC regions, thus indicating a higher degree of anisotropy within the intracellular space in comparison to the combined intra- and extracellular spaces. A decreasing trend in the FA of NAA and water was observed between R1 and R2, while the radial diffusivity (RD) for both molecules increased. The increase in RD(NAA) is particularly significant, thus explaining the more significant decrease in FA(NAA) between the two regions. It is suggested that diffusion tensor spectroscopy of NAA can potentially be used to further characterize microscopic anatomic organization in white matter. Copyright 2007 Wiley-Liss, Inc.

  18. Dysembryoplastic neuroepithelial tumors: proton MR spectroscopy, diffusion and perfusion characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Bulakbasi, Nail; Kocaoglu, Murat; Sanal, Tuba H.; Tayfun, Cem [Gulhane Military Medical Academy, Department of Radiology, Military Medical Faculty, Ankara (Turkey)

    2007-10-15

    We describe the magnetic resonance (MR) imaging characteristics of dysembryoplastic neuroepithelial tumors (DNT) and discuss their differential diagnosis. Proton MR spectroscopy (TE 30 and 136 ms), diffusion-weighted and perfusion images were retrospectively evaluated in 22 patients with pathologically proven DNT (17 male and 5 female, mean age 18.7 years) and 14 control subjects (10 male and 4 female, mean age 16.9 years). The results from the DNT patients and from the control subjects were compared using an independent sample t-test and the degree of correlation was tested by Pearson's correlation. All DNTs were solitary and in a supratentorial cortical or subcortical location (ten temporal, eight frontal and four parietal). They had low-signal on T1-weighted images and high-signal on T2-weighted images without a prominent mass effect. Additionally a cystic appearance (six patients, 27.3%), cortical dysplasia (six patients, 27.3%) and contrast enhancement (four patients, 18.2%) were also noted. No significant differences were detected in NAA/Cho, NAA/Cr, NAA/Cho+Cr or Cho/Cr ratios between DNT and normal brain. DNTs had a significantly higher mI/Cr ratio and apparent diffusion coefficient (ADC) values and lower cerebral blood values than normal parenchyma (P < 0.001). ADC had the highest correlation with the diagnosis of DNT (r = 0.996) followed by relative cerebral blood volume (rCBV) (r = -0.883) and mI/Cr ratio (r = 0.663). Proton MR spectroscopy, diffusion-weighted and perfusion imaging characteristics of DNTs provide additional information to their MR imaging findings. The MR spectrum showing a slight increase in mI/Cr ratio, and higher ADC and lower rCBV values than normal parenchyma help to differentiate DNTs from other cortical tumors, which had higher rCBV and lower ADC values than DNTs. (orig.)

  19. A High Grade Gliomatosis Cerebri Case Report; MR, Diffusion MR and MR Spectroscopy Findings

    Directory of Open Access Journals (Sweden)

    Mehmet Beyazal

    2014-03-01

    Full Text Available Gliomatosis cerebri is a rare primary diffuse cerebral malignity. It is characterized by diffuse proliferation of neoplastic glial cells that involve one or more cerebral lobes. For definitive diagnosis histopathological examination is required. Advanced magnetic resonance imaging techniques are very useful in pretreatment diagnosis-staging and post-treatment follow-up. In this report a patient with gliomatozis cerebri was presented associated with the findings of magnetic resonance images, diffusion weighted images and magnetic resonance spectroscopy. Also the importance and role of magnetic resonance spectroscopy in the diagnosis and staging gliomatosis cerebri, was discussed

  20. Terahertz Spectroscopy and Imaging

    CERN Document Server

    Zeitler, Axel; Kuwata-Gonokami, Makoto

    2013-01-01

    "This book presents the current state of knowledge in the field of terahertz spectroscopy, providing a comprehensive source of information for beginners and experienced researchers alike whose interests lie in this area. The book aims to explain the fundamental physics that underpins terahertz  technology and to describe its key applications. Highlights of scientific research in the field of terahertz science are also outlined in some chapters, providing an overview as well as giving an insight into future directions for research.  Over the past decade terahertz spectroscopy has developed into one of the most rapidly growing areas of its kind, gaining an important impact across a wide range of scientific disciplines. Due to substantial advances in femtosecond laser technology, terahertz time-domain spectroscopy (THz-TDS) has established itself as the dominant spectroscopic technique for experimental scientists interested in measurements at this frequency range. In solids and liquids THz radiation is in reso...

  1. The added value of advanced neuro-imaging (MR diffusion ...

    African Journals Online (AJOL)

    Introduction: Primary CNS lymphoma is difficult to diagnose with conventional imaging modalities. Magnetic resonance proton spectroscopy, dynamic susceptibility contrast DSC perfusion and diffusion weighted images have been recently investigated as a problem-solving tool for evaluation of primary CNS lymphoma with ...

  2. Photoacoustic imaging and spectroscopy

    CERN Document Server

    Wang, Lihong

    2009-01-01

    Photoacoustics promises to revolutionize medical imaging and may well make as dramatic a contribution to modern medicine as the discovery of the x-ray itself once did. Combining electromagnetic and ultrasonic waves synergistically, photoacoustics can provide deep speckle-free imaging with high electromagnetic contrast at high ultrasonic resolution and without any health risk. While photoacoustic imaging is probably the fastest growing biomedical imaging technology, this book is the first comprehensive volume in this emerging field covering both the physics and the remarkable noninvasive applic

  3. Multimodal fluorescence imaging spectroscopy

    NARCIS (Netherlands)

    Stopel, Martijn H W; Blum, Christian; Subramaniam, Vinod; Engelborghs, Yves; Visser, Anthonie J.W.G.

    2014-01-01

    Multimodal fluorescence imaging is a versatile method that has a wide application range from biological studies to materials science. Typical observables in multimodal fluorescence imaging are intensity, lifetime, excitation, and emission spectra which are recorded at chosen locations at the sample.

  4. Prostate cancer: diagnostic value of dynamic contrast-enhanced MRI, diffusion weighted imaging and 3D 1H-MR spectroscopy

    International Nuclear Information System (INIS)

    Shi Hao; Wu Lebin; Ding Hongyu; Zhao Bin; Wang Tao; Yang Zhenzhen; Qiu Xiuling; Li Huihua; Qu Lei; Wu Yulong

    2006-01-01

    Objective: To explore the applying value of the diagnosis of dynamic contrast-enhanced MRI (DCE-MRI), diffusion weighted imaging (DWI) and 3D 1 H-MR spectroscopy (MRS) in prostate cancer (PC). Methods: Thirty-two cases with PC and 64 cases with benign prostatic hyperplasia (BPH) which were confirmed with biopsy-proven, operation and follow-up, and 29 healthy volunteers underwent the examinations of DCE-MRI, DWI and MRS. The signal intensity, ADC value, and Cho/Cit ratio and (Cho + Cr)/Cit ratio were measured respectively on the lesions of PC and BPH, normal prostatic peripheral zone (PZ) and normal prostatic central gland (CG) of DCE-MRI, DWI and MRS. The results were statistically treated with ANOVA. Results: The lesions showed obvious enhancement in the early phase of DCE-MRI and washed out in late phase in 18 of 22 cases with PC, who underwent the examination of DCE-MRI. The enhancement was obvious in early and strengthened gradually, and then went to decrease in late phase after peak value on the lesions in 38 of 40 cases with BPH. The signal intensities from different time and different lesions and tissues were treated statistically and the results showed that there were significant differences (P 0.05). The lesions were shown lower signal intensity on ADC map in 26 cases with PC, who were examined with DWI and the average ADC value was (104.23±26.15) x 10 -5 mm 2 /s. The average ADC Value of the lesions of 43 cases with BPH was (175.21±64.86) x 10 -5 mm 2 /s. The statistical analysis showed that there were significant differences between PC, BPH and CG except between PZ and BPH. Average Cho/Cit ratio and average (Cho + Cr)/Cit ratio of the lesions of PC were 2.26±0.91 and 2.85±1.01 respectively in 17 cases with PC, who were performed with MRS. The average Cho/Cit ratio and average (Cho + Cr)/Cit ratio were 0.46±0.23 and 0.57±0.20 respectively in 35 cases with BPH. After the statistical analyzing, the results presented that there were significant

  5. Imaging spectroscopy for characterisation of grass swards

    NARCIS (Netherlands)

    Schut, A.G.T.

    2003-01-01

    Keywords: Imaging spectroscopy, imaging spectrometry, remote sensing, reflection, reflectance, grass sward, white clover, recognition, characterisation, ground cover, growth monitoring, stress detection, heterogeneity quantification

    The potential of imaging spectroscopy as a tool for

  6. Diffuse Optical Tomography for Brain Imaging: Theory

    Science.gov (United States)

    Yuan, Zhen; Jiang, Huabei

    Diffuse optical tomography (DOT) is a noninvasive, nonionizing, and inexpensive imaging technique that uses near-infrared light to probe tissue optical properties. Regional variations in oxy- and deoxy-hemoglobin concentrations as well as blood flow and oxygen consumption can be imaged by monitoring spatiotemporal variations in the absorption spectra. For brain imaging, this provides DOT unique abilities to directly measure the hemodynamic, metabolic, and neuronal responses to cells (neurons), and tissue and organ activations with high temporal resolution and good tissue penetration. DOT can be used as a stand-alone modality or can be integrated with other imaging modalities such as fMRI/MRI, PET/CT, and EEG/MEG in studying neurophysiology and pathology. This book chapter serves as an introduction to the basic theory and principles of DOT for neuroimaging. It covers the major aspects of advances in neural optical imaging including mathematics, physics, chemistry, reconstruction algorithm, instrumentation, image-guided spectroscopy, neurovascular and neurometabolic coupling, and clinical applications.

  7. Bayesian regularization of diffusion tensor images

    DEFF Research Database (Denmark)

    Frandsen, Jesper; Hobolth, Asger; Østergaard, Leif

    2007-01-01

    Diffusion tensor imaging (DTI) is a powerful tool in the study of the course of nerve fibre bundles in the human brain. Using DTI, the local fibre orientation in each image voxel can be described by a diffusion tensor which is constructed from local measurements of diffusion coefficients along...... several directions. The measured diffusion coefficients and thereby the diffusion tensors are subject to noise, leading to possibly flawed representations of the three dimensional fibre bundles. In this paper we develop a Bayesian procedure for regularizing the diffusion tensor field, fully utilizing...

  8. Mid infrared upconversion spectroscopy using diffuse reflectance

    DEFF Research Database (Denmark)

    Sanders, Nicolai Højer; Kehlet, Louis M.; Dam, Jeppe Seidelin

    2014-01-01

    specifically that upconversion methods can be deployed using a diffuse reflectance setup where the test sample is irradiated by a thermal light source, i.e. a globar. The diffuse reflectance geometry is particularly well suited when a transmission setup cannot be used. This situation may happen for highly...

  9. Diffuse axonal injury: detection of changes in anisotropy of water diffusion by diffusion-weighted imaging

    International Nuclear Information System (INIS)

    Chan, J.H.M.; Tsui, E.Y.K.; Yuen, M.K.; Peh, W.C.G.; Fong, D.; Fok, K.F.; Leung, K.M.; Fung, K.K.L.

    2003-01-01

    Myelinated axons of white matter demonstrate prominent directional differences in water diffusion. We performed diffusion-weighted imaging on ten patients with head injury to explore the feasibility of using water diffusion anisotropy for quantitating diffuse axonal injury. We showed significant decrease in diffusion anisotropy indices in areas with or without signal abnormality on T2 and T2*-weighted images. We conclude that the water diffusion anisotropy index a potentially useful, sensitive and quantitative way of diagnosing and assessing patients with diffuse axonal injury. (orig.)

  10. Neutron spin-echo spectroscopy for diffusion in crystalline solids

    International Nuclear Information System (INIS)

    Kaisermayr, M.; Rennhofer, M.; Vogl, G.; Pappas, C.; Longeville, S.

    2002-01-01

    Neutron spin-echo spectroscopy (NSE) offers unprecedented opportunities in the investigation of diffusion in crystalline systems due to its outstanding energy resolution. NSE not only enables measurements at lower diffusivities than the established techniques of neutron spectroscopy, but it also gives a very immediate access to the different time scales involved in the diffusion process. This is demonstrated in detail on the example of the binary alloy NiGa where the Ni atoms hop between regular sites on the Ni sublattice and anti-sites on the Ga sublattice. Experiments on two different NSE instruments are compared to measurements using neutron backscattering spectroscopy. The potential of NSE for the investigation of jump diffusion and experimental requirements are discussed

  11. High angular resolution diffusion imaging : processing & visualization

    NARCIS (Netherlands)

    Prckovska, V.

    2010-01-01

    Diffusion tensor imaging (DTI) is a recent magnetic resonance imaging (MRI) technique that can map the orientation architecture of neural tissues in a completely non-invasive way by measuring the directional specificity (anisotropy) of the local water diffusion. However, in areas of complex fiber

  12. Diffusion measurements in binary liquid mixtures by Raman spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.; Hansen, Susanne Brunsgaard; Shapiro, Alexander

    2007-01-01

    It is shown that Raman spectroscopy allows determination of the molar fractions in mixtures subjected to molecular diffusion. Spectra of three binary systems, benzene/n-hexane, benzene/cyclohexane, and benzene/ acetone, were obtained during vertical (exchange) diffusion at several different heights...... in the literature were found, even in a thermostatically controlled diffusion cell, recording spectra through circulating water. For the system benzene/acetone, the determined diffusion coefficients were in good agreement with the literature data. The limitations of the Raman method are discussed...

  13. Image denoising using non linear diffusion tensors

    International Nuclear Information System (INIS)

    Benzarti, F.; Amiri, H.

    2011-01-01

    Image denoising is an important pre-processing step for many image analysis and computer vision system. It refers to the task of recovering a good estimate of the true image from a degraded observation without altering and changing useful structure in the image such as discontinuities and edges. In this paper, we propose a new approach for image denoising based on the combination of two non linear diffusion tensors. One allows diffusion along the orientation of greatest coherences, while the other allows diffusion along orthogonal directions. The idea is to track perfectly the local geometry of the degraded image and applying anisotropic diffusion mainly along the preferred structure direction. To illustrate the effective performance of our model, we present some experimental results on a test and real photographic color images.

  14. Diffusion weighted imaging by MR method

    International Nuclear Information System (INIS)

    Horikawa, Yoshiharu; Naruse, Shoji; Ebisu, Toshihiko; Tokumitsu, Takuaki; Ueda, Satoshi; Tanaka, Chuzo; Higuchi, Toshihiro; Umeda, Masahiro.

    1993-01-01

    Diffusion weighted magnetic resonance imaging is a recently developed technique used to examine the micromovement of water molecules in vivo. We have applied this technique to examine various kinds of brain diseases, both experimentally and clinically. The calculated apparent diffusion coefficient (ADC) in vivo showed reliable values. In experimentally induced brain edema in rats, the pathophysiological difference of the type of edema (such as cytotoxic, and vasogenic) could be differentiated on the diffusion weighted MR images. Cytotoxic brain edema showed high intensity (slower diffusion) on the diffusion weighted images. On the other hand, vasogenic brain edema showed a low intensity image (faster diffusion). Diffusion anisotropy was demonstrated according to the direction of myelinated fibers and applied motion proving gradient (MPG). This anisotropy was also demonstrated in human brain tissue along the course of the corpus callosum, pyramidal tract and optic radiation. In brain ischemia cases, lesions were detected as high signal intensity areas, even one hour after the onset of ischemia. Diffusion was faster in brain tumor compared with normal brain. Histological differences were not clearly reflected by the ADC value. In epidermoid tumor cases, the intensity was characteristically high, was demonstrated, and the cerebrospinal fluid border was clearly demonstrated. New clinical information obtainable with this molecular diffusion method will prove to be useful in various clinical studies. (author)

  15. Metabolomics of Breast Cancer Using High-Resolution Magic Angle Spinning Magnetic Resonance Spectroscopy: Correlations with 18F-FDG Positron Emission Tomography-Computed Tomography, Dynamic Contrast-Enhanced and Diffusion-Weighted Imaging MRI.

    Science.gov (United States)

    Yoon, Haesung; Yoon, Dahye; Yun, Mijin; Choi, Ji Soo; Park, Vivian Youngjean; Kim, Eun-Kyung; Jeong, Joon; Koo, Ja Seung; Yoon, Jung Hyun; Moon, Hee Jung; Kim, Suhkmann; Kim, Min Jung

    2016-01-01

    Our goal in this study was to find correlations between breast cancer metabolites and conventional quantitative imaging parameters using high-resolution magic angle spinning (HR-MAS) magnetic resonance spectroscopy (MRS) and to find breast cancer subgroups that show high correlations between metabolites and imaging parameters. Between August 2010 and December 2013, we included 53 female patients (mean age 49.6 years; age range 32-75 years) with a total of 53 breast lesions assessed by the Breast Imaging Reporting and Data System. They were enrolled under the following criteria: breast lesions larger than 1 cm in diameter which 1) were suspicious for malignancy on mammography or ultrasound (US), 2) were pathologically confirmed to be breast cancer with US-guided core-needle biopsy (CNB) 3) underwent 3 Tesla MRI with dynamic contrast-enhanced (DCE) and diffusion-weighted imaging (DWI) and positron emission tomography-computed tomography (PET-CT), and 4) had an attainable immunohistochemistry profile from CNB. We acquired spectral data by HR-MAS MRS with CNB specimens and expressed the data as relative metabolite concentrations. We compared the metabolites with the signal enhancement ratio (SER), maximum standardized FDG uptake value (SUV max), apparent diffusion coefficient (ADC), and histopathologic prognostic factors for correlation. We calculated Spearman correlations and performed a partial least squares-discriminant analysis (PLS-DA) to further classify patient groups into subgroups to find correlation differences between HR-MAS spectroscopic values and conventional imaging parameters. In a multivariate analysis, the PLS-DA models built with HR-MAS MRS metabolic profiles showed visible discrimination between high and low SER, SUV, and ADC. In luminal subtype breast cancer, compared to all cases, high SER, ADV, and SUV were more closely clustered by visual assessment. Multiple metabolites were correlated with SER and SUV in all cases. Multiple metabolites showed

  16. Metabolomics of Breast Cancer Using High-Resolution Magic Angle Spinning Magnetic Resonance Spectroscopy: Correlations with 18F-FDG Positron Emission Tomography-Computed Tomography, Dynamic Contrast-Enhanced and Diffusion-Weighted Imaging MRI.

    Directory of Open Access Journals (Sweden)

    Haesung Yoon

    Full Text Available Our goal in this study was to find correlations between breast cancer metabolites and conventional quantitative imaging parameters using high-resolution magic angle spinning (HR-MAS magnetic resonance spectroscopy (MRS and to find breast cancer subgroups that show high correlations between metabolites and imaging parameters.Between August 2010 and December 2013, we included 53 female patients (mean age 49.6 years; age range 32-75 years with a total of 53 breast lesions assessed by the Breast Imaging Reporting and Data System. They were enrolled under the following criteria: breast lesions larger than 1 cm in diameter which 1 were suspicious for malignancy on mammography or ultrasound (US, 2 were pathologically confirmed to be breast cancer with US-guided core-needle biopsy (CNB 3 underwent 3 Tesla MRI with dynamic contrast-enhanced (DCE and diffusion-weighted imaging (DWI and positron emission tomography-computed tomography (PET-CT, and 4 had an attainable immunohistochemistry profile from CNB. We acquired spectral data by HR-MAS MRS with CNB specimens and expressed the data as relative metabolite concentrations. We compared the metabolites with the signal enhancement ratio (SER, maximum standardized FDG uptake value (SUV max, apparent diffusion coefficient (ADC, and histopathologic prognostic factors for correlation. We calculated Spearman correlations and performed a partial least squares-discriminant analysis (PLS-DA to further classify patient groups into subgroups to find correlation differences between HR-MAS spectroscopic values and conventional imaging parameters.In a multivariate analysis, the PLS-DA models built with HR-MAS MRS metabolic profiles showed visible discrimination between high and low SER, SUV, and ADC. In luminal subtype breast cancer, compared to all cases, high SER, ADV, and SUV were more closely clustered by visual assessment. Multiple metabolites were correlated with SER and SUV in all cases. Multiple metabolites

  17. Basic principles of diffusion-weighted imaging

    International Nuclear Information System (INIS)

    Bammer, Roland.

    2003-01-01

    In diffusion-weighted MRI (DWI), image contrast is determined by the random microscopic motion of water protons. During the last years, DWI has become an important modality in the diagnostic work-up of acute ischemia in the CNS. There are also a few promising reports about the application of DWI to other regions in the human body, such as the vertebral column or the abdomen. This manuscript provides an introduction into the basics of DWI and Diffusion Tensor imaging. The potential of various MR sequences in concert with diffusion preparation are discussed with respect to acquisition speed, spatial resolution, and sensitivity to bulk physiologic motion. More advanced diffusion measurement techniques, such as high angular resolution diffusion imaging, are also addressed

  18. Imaging brain microstructure with diffusion MRI

    DEFF Research Database (Denmark)

    Alexander, Daniel C; Dyrby, Tim B; Nilsson, Markus

    2018-01-01

    This article gives an overview of microstructure imaging of the brain with diffusion MRI and reviews the state of the art. The microstructure-imaging paradigm aims to estimate and map microscopic properties of tissue using a model that links these properties to the voxel scale MR signal. Imaging ...

  19. Diffusion tensor imaging in spinal cord compression

    International Nuclear Information System (INIS)

    Wang, Wei; Qin, Wen; Hao, Nanxin; Wang, Yibin; Zong, Genlin

    2012-01-01

    Background Although diffusion tensor imaging has been successfully applied in brain research for decades, several main difficulties have hindered its extended utilization in spinal cord imaging. Purpose To assess the feasibility and clinical value of diffusion tensor imaging and tractography for evaluating chronic spinal cord compression. Material and Methods Single-shot spin-echo echo-planar DT sequences were scanned in 42 spinal cord compression patients and 49 healthy volunteers. The mean values of the apparent diffusion coefficient and fractional anisotropy were measured in region of interest at the cervical and lower thoracic spinal cord. The patients were divided into two groups according to the high signal on T2WI (the SCC-HI group and the SCC-nHI group for with or without high signal). A one-way ANOVA was used. Diffusion tensor tractography was used to visualize the morphological features of normal and impaired white matter. Results There were no statistically significant differences in the apparent diffusion coefficient and fractional anisotropy values between the different spinal cord segments of the normal subjects. All of the patients in the SCC-HI group had increased apparent diffusion coefficient values and decreased fractional anisotropy values at the lesion level compared to the normal controls. However, there were no statistically significant diffusion index differences between the SCC-nHI group and the normal controls. In the diffusion tensor imaging maps, the normal spinal cord sections were depicted as fiber tracts that were color-encoded to a cephalocaudal orientation. The diffusion tensor images were compressed to different degrees in all of the patients. Conclusion Diffusion tensor imaging and tractography are promising methods for visualizing spinal cord tracts and can provide additional information in clinical studies in spinal cord compression

  20. Diffusion tensor and diffusion weighted imaging. Pictorial mathematics

    Energy Technology Data Exchange (ETDEWEB)

    Nakada, Tsutomu [California Univ., Davis, CA (United States)

    1995-06-01

    A new imaging algorithm for the treatment of a second order apparent diffusion tensor, D{sub app}{sup {xi}} is described. The method calls for only mathematics of images (pictorial mathematics) without necessity of eigenvalues/eigenvectors estimation. Nevertheless, it is capable of extracting properties of D{sub app}{sup {xi}} invariant to observation axes. While trace image is an example of images weighted by invariance of the tensor matrix, three dimensional anisotropy (3DAC) contrast represents the imaging method making use to anisotropic direction of tensor ellipsoid producing color coded contrast of exceptionally high anatomic resolution. Contrary to intuition, the processes require only a simple algorithm directly applicable to clinical magnetic resonance imaging (MRI). As a contrast method which precisely represents physical characteristics of a target tissue, invariant D{sub app}{sup {xi}} images produced by pictorial mathematics possess significant potential for a number of biological and clinical applications. (author).

  1. Higher-order tensors in diffusion imaging

    NARCIS (Netherlands)

    Schultz, T.; Fuster, A.; Ghosh, A.; Deriche, R.; Florack, L.M.J.; Lim, L.H.; Westin, C.-F.; Vilanova, A.; Burgeth, B.

    2014-01-01

    Diffusion imaging is a noninvasive tool for probing the microstructure of fibrous nerve and muscle tissue. Higher-order tensors provide a powerful mathematical language to model and analyze the large and complex data that is generated by its modern variants such as High Angular Resolution Diffusion

  2. Establishing the diffuse correlation spectroscopy signal relationship with blood flow.

    Science.gov (United States)

    Boas, David A; Sakadžić, Sava; Selb, Juliette; Farzam, Parisa; Franceschini, Maria Angela; Carp, Stefan A

    2016-07-01

    Diffuse correlation spectroscopy (DCS) measurements of blood flow rely on the sensitivity of the temporal autocorrelation function of diffusively scattered light to red blood cell (RBC) mean square displacement (MSD). For RBCs flowing with convective velocity [Formula: see text], the autocorrelation is expected to decay exponentially with [Formula: see text], where [Formula: see text] is the delay time. RBCs also experience shear-induced diffusion with a diffusion coefficient [Formula: see text] and an MSD of [Formula: see text]. Surprisingly, experimental data primarily reflect diffusive behavior. To provide quantitative estimates of the relative contributions of convective and diffusive movements, we performed Monte Carlo simulations of light scattering through tissue of varying vessel densities. We assumed laminar vessel flow profiles and accounted for shear-induced diffusion effects. In agreement with experimental data, we found that diffusive motion dominates the correlation decay for typical DCS measurement parameters. Furthermore, our model offers a quantitative relationship between the RBC diffusion coefficient and absolute tissue blood flow. We thus offer, for the first time, theoretical support for the empirically accepted ability of the DCS blood flow index ([Formula: see text]) to quantify tissue perfusion. We find [Formula: see text] to be linearly proportional to blood flow, but with a proportionality modulated by the hemoglobin concentration and the average blood vessel diameter.

  3. Diagnostic value of proton MR spectroscopy and diffusion-weighted MR imaging in childhood inherited neurometabolic brain diseases and review of the literature

    International Nuclear Information System (INIS)

    Cakmakci, Handan; Pekcevik, Yeliz; Yis, Uluc; Unalp, Aycan; Kurul, Semra

    2010-01-01

    The purpose of this study is to evaluate parenchymal diffusion properties and metabolite ratios in affected brain tissues of inherited neurometabolic brain diseases with an overview of the current literature about the diagnostic data of both techniques in childhood inherited metabolic brain diseases. The study group was consisting, 19 patients (15 males, 4 females; mean age, 54 months (4.5 years); age range, 1-171 months (14.25 years)) diagnosed with inherited neurometabolic brain disease. Single- and multivoxel proton MRS was carried out and NAA/Cr, Cho/Cr, mI/Cr, Glx/Cr ratios were calculated. Presence of lactate peak and abnormal different peaks were noted. ADC values were calculated from brain lesions. Results are compared with age and sex matched normal subjects. Elevated NAA/Cr ratio (Canavan disease), galactitol peak (galactosemia) at 3.7 ppm, branched chain amino acids (Maple syrup urine disease-MSUD) at 0.9 ppm were seen on different diseases. In Leigh disease and MSUD restricted diffusion was detected. Different diffusion properties were seen only in one Glutaric aciduria lesions. NAA/Cr ratios and calculated ADC values were significantly different from normal subjects (p < 0.05). DWI combined with MRS are complementary methods to routine cranial MRI for evaluating neurometabolic diseases which can give detailed information about neurochemistry of affected brain areas.

  4. Diagnostic value of proton MR spectroscopy and diffusion-weighted MR imaging in childhood inherited neurometabolic brain diseases and review of the literature

    Energy Technology Data Exchange (ETDEWEB)

    Cakmakci, Handan, E-mail: handan.cakmakci@deu.edu.t [Dokuz Eylul University Faculty of Medicine, Department of Radiology, Izmir (Turkey); Pekcevik, Yeliz [Dokuz Eylul University Faculty of Medicine, Department of Radiology, Izmir (Turkey); Yis, Uluc [Dokuz Eylul University Faculty of Medicine, Department of Pediatric Neurology, Izmir (Turkey); Unalp, Aycan [Behcet Uz Hospital, Department of Pediatric Neurology, Izmir (Turkey); Kurul, Semra [Dokuz Eylul University Faculty of Medicine, Department of Pediatric Neurology, Izmir (Turkey)

    2010-06-15

    The purpose of this study is to evaluate parenchymal diffusion properties and metabolite ratios in affected brain tissues of inherited neurometabolic brain diseases with an overview of the current literature about the diagnostic data of both techniques in childhood inherited metabolic brain diseases. The study group was consisting, 19 patients (15 males, 4 females; mean age, 54 months (4.5 years); age range, 1-171 months (14.25 years)) diagnosed with inherited neurometabolic brain disease. Single- and multivoxel proton MRS was carried out and NAA/Cr, Cho/Cr, mI/Cr, Glx/Cr ratios were calculated. Presence of lactate peak and abnormal different peaks were noted. ADC values were calculated from brain lesions. Results are compared with age and sex matched normal subjects. Elevated NAA/Cr ratio (Canavan disease), galactitol peak (galactosemia) at 3.7 ppm, branched chain amino acids (Maple syrup urine disease-MSUD) at 0.9 ppm were seen on different diseases. In Leigh disease and MSUD restricted diffusion was detected. Different diffusion properties were seen only in one Glutaric aciduria lesions. NAA/Cr ratios and calculated ADC values were significantly different from normal subjects (p < 0.05). DWI combined with MRS are complementary methods to routine cranial MRI for evaluating neurometabolic diseases which can give detailed information about neurochemistry of affected brain areas.

  5. Distribution of diffusion times determined by fluorescence (lifetime) correlation spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Pánek, Jiří; Loukotová, Lenka; Hrubý, Martin; Štěpánek, Petr

    2018-01-01

    Roč. 51, č. 8 (2018), s. 2796-2804 ISSN 0024-9297 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : polymer solution * fluorescence correlation spectroscopy * diffusion time distribution Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 5.835, year: 2016

  6. Basic consideration of diffusion/perfusion imaging

    International Nuclear Information System (INIS)

    Tamagawa, Yoichi; Kimura, Hirohiko; Matsuda, Tsuyoshi; Kawamura, Yasutaka; Nakatsugawa, Shigekazu; Ishii, Yasushi; Sakuma, Hajime; Tsukamoto, Tetsuji.

    1990-01-01

    In magnetic resonance imaging (MRI), microscopic motion of biological system such as molecular diffusion of water and microcirculation of blood in the capillary network (perfusion) has been proposed to cause signal attenuation as an intravoxel incoherent motion (IVIM). Quantitative imaging of the IVIM phenomenon was attempted to generate from a set of spin-echo (SE) sequences with or without sensitization by motion probing gradient (MPG). The IVIM imaging is characterized by a parameter, apparent diffusion coefficient (ADC), which is an integration of both the diffusion and the perfusion factor on voxel-by-voxel basis. Hard ware was adjusted to avoid image artifact mainly produced by eddy current. Feasibility of the method was tested using bottle phantom filled with water at different temperature and acetone, and the calculated ADC values of these media corresponded well with accepted values of diffusion. The method was then applied to biological system to investigate mutual participation of diffusion/perfusion on the ADC value. The result of tumor model born on nude mouse suggested considerable participation of perfusion factor which immediately disappeared after sacrificing the animal. Meanwhile, lower value of sacrificed tissue without microcirculation was suggested to have some restriction of diffusion factor by biological tissue. To substantiate the restriction effect on the diffusion, a series of observation have made on a fiber phantom, stalk of celory with botanical fibers and human brain with nerve fibers, in applying unidirectional MPG along the course of these banch of fiber system. The directional restriction effect of diffusion along the course of fiber (diffusion anisotrophy) was clearly visualized as directional change of ADC value. The present method for tissue characterization by diffusion/perfusion on microscopic level will provide a new insight for evaluation of functional derangement in human brain and other organs. (author)

  7. An introduction to diffusion tensor image analysis.

    Science.gov (United States)

    O'Donnell, Lauren J; Westin, Carl-Fredrik

    2011-04-01

    Diffusion tensor magnetic resonance imaging (DTI) is a relatively new technology that is popular for imaging the white matter of the brain. This article provides a basic and broad overview of DTI to enable the reader to develop an intuitive understanding of these types of data, and an awareness of their strengths and weaknesses. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Inference of protein diffusion probed via fluorescence correlation spectroscopy

    Science.gov (United States)

    Tsekouras, Konstantinos

    2015-03-01

    Fluctuations are an inherent part of single molecule or few particle biophysical data sets. Traditionally, ``noise'' fluctuations have been viewed as a nuisance, to be eliminated or minimized. Here we look on how statistical inference methods - that take explicit advantage of fluctuations - have allowed us to draw an unexpected picture of single molecule diffusional dynamics. Our focus is on the diffusion of proteins probed using fluorescence correlation spectroscopy (FCS). First, we discuss how - in collaboration with the Bustamante and Marqusee labs at UC Berkeley - we determined using FCS data that individual enzymes are perturbed by self-generated catalytic heat (Riedel et al, Nature, 2014). Using the tools of inference, we found how distributions of enzyme diffusion coefficients shift in the presence of substrate revealing that enzymes performing highly exothermic reactions dissipate heat by transiently accelerating their center of mass following a catalytic reaction. Next, when molecules diffuse in the cell nucleus they often appear to diffuse anomalously. We analyze FCS data - in collaboration with Rich Day at the IU Med School - to propose a simple model for transcription factor binding-unbinding in the nucleus to show that it may give rise to apparent anomalous diffusion. Here inference methods extract entire binding affinity distributions for the diffusing transcription factors, allowing us to precisely characterize their interactions with different components of the nuclear environment. From this analysis, we draw key mechanistic insight that goes beyond what is possible by simply fitting data to ``anomalous diffusion'' models.

  9. Diffusion-Weighted Imaging and Diffusion Tensor Imaging of Asymptomatic Lumbar Disc Herniation

    OpenAIRE

    Sakai, Toshinori; Miyagi, Ryo; Yamabe, Eiko; Fujinaga, Yasunari; Bhatia, Nitin N.; Yoshioka, Hiroshi

    2014-01-01

    Diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) were performedon a healthy 31-year-old man with asymptomatic lumbar disc herniation. Althoughthe left S1 nerve root was obviously entrapped by a herniated mass, neither DWI nor DTI showed any significant findings for the nerve root. Decreased apparent diffusion coefficient (ADC) values and increased fractional anisotropy (FA) values were found. These results are contrary to those in previously published studies of symptomatic...

  10. Diffusion weighted imaging (DWI) in the abdomen

    International Nuclear Information System (INIS)

    Collaku, A.

    2013-01-01

    Full text: Introduction: The use of diffusion weighted images when performing abdomen MRI has been increased during the last years; achieving high quality images for a short period of time remains still a challenge. Learning points: We present a literature review together with our experience in optimizing the DW imaging in the abdomen, focused on creating high density ADC maps and handling the uncooperative patients. Discussion: The factors that influence the image quality are discussed as well. Conclusion: The factors that influence the image quality are discussed as well

  11. Interpolation of diffusion weighted imaging datasets

    DEFF Research Database (Denmark)

    Dyrby, Tim B; Lundell, Henrik; Burke, Mark W

    2014-01-01

    anatomical details and signal-to-noise-ratio for reliable fibre reconstruction. We assessed the potential benefits of interpolating DWI datasets to a higher image resolution before fibre reconstruction using a diffusion tensor model. Simulations of straight and curved crossing tracts smaller than or equal......Diffusion weighted imaging (DWI) is used to study white-matter fibre organisation, orientation and structural connectivity by means of fibre reconstruction algorithms and tractography. For clinical settings, limited scan time compromises the possibilities to achieve high image resolution for finer...... interpolation methods fail to disentangle fine anatomical details if PVE is too pronounced in the original data. As for validation we used ex-vivo DWI datasets acquired at various image resolutions as well as Nissl-stained sections. Increasing the image resolution by a factor of eight yielded finer geometrical...

  12. Correlation analysis of expressions of PTEN and p53 with the value obtained by magnetic resonance spectroscopy and apparent diffusion coefficient in the tumor and the tumor-adjacent area in magnetic resonance imaging for glioblastoma.

    Science.gov (United States)

    Li, Yunyun; Ji, Feng; Jiang, Yuzhi; Zhao, Ting; Xu, Chongfu

    2018-01-01

    To explore the correlation of the expression levels of phosphate and tension homology deleted on chromosome ten (PTEN) and p53 of glioblastoma multiforme (GBM) with the value obtained by magnetic resonance spectroscopy (MRS) and apparent diffusion coefficient (ADC) in the tumor and the tumor-adjacent area in magnetic resonance imaging (MRI). A total of 38 patients were operated for GBM. All the patients had received diffusion-weighted imaging (DWI) and MRS prior to surgery. ADC of water molecules and values of metabolite indexes of MRS, including n-acetyl aspartate (NAA), choline (Cho) and creatine (Cr), were recorded, and the ratios of Cho/NAA, Cho/Cr and NAA/Cr were calculated. Hematoxylin-eosin (H&E) staining was done to examine the morphology of tumor and of tumor-adjacent tissues; immunohistochemistry (IHC) was performed to examine the expressions of PTEN and p53 in the tumor and the tumor-adjacent area. Finally, the correlations of the expressions of PTEN and p53 with ADC, Cho/NAA, Cho/Cr and NAA/Cr of the tumor and the tumor-adjacent area were analyzed. H&E staining showed that GBM tissues had disordered morphology, different sizes of cells, large cell nuclei and significant cell heterogeneity. IHC indicated that the expression level of p53 protein in the tumor was significantly higher than in the tumor-adjacent tissues (pCorrelation analysis indicated that PTEN levels in the tumor and the tumor-adjacent area were positively correlated with ADC in the corresponding area, while p53 in the tumor and the tumor-adjacent area was negatively correlated with ADC in the corresponding area. Cho/NAA and Cho/Cr in the tumor were positively correlated with p53 in the tumor, but negatively correlated with PTEN in the tumor. However, NAA/Cr of the tumor was irrelevant to the levels of PTEN and p53. The test results of DWI and MRS of patients with GBM can accurately reflect the inactivation or mutation of PTEN and p53.

  13. Diffusion-weighted MR imaging in leukodystrophies

    Energy Technology Data Exchange (ETDEWEB)

    Patay, Zoltan [King Faisal Specialist Hospital and Research Centre, Department of Radiology, Riyadh (Saudi Arabia)

    2005-11-01

    Leukodystrophies are genetically determined metabolic diseases, in which the underlying biochemical abnormality interferes with the normal build-up and/or maintenance of myelin, which leads to hypo- (or arrested) myelination, or dysmyelination with resultant demyelination. Although conventional magnetic resonance imaging has significantly contributed to recent progress in the diagnostic work-up of these diseases, diffusion-weighted imaging has the potential to further improve our understanding of underlying pathological processes and their dynamics through the assessment of normal and abnormal diffusion properties of cerebral white matter. Evaluation of conventional diffusion-weighted and ADC map images allows the detection of major diffusion abnormalities and the identification of various edema types, of which the so-called myelin edema is particularly relevant to leukodystrophies. Depending on the nature of histopathological changes, stage and progression gradient of diseases, various diffusion-weighted imaging patterns may be seen in leukodystrophies. Absent or low-grade myelin edema is found in mucopolysaccharidoses, GM gangliosidoses, Zellweger disease, adrenomyeloneuropathy, L-2-hydroxyglutaric aciduria, non-ketotic hyperglycinemia, classical phenylketonuria, Van der Knaap disease and the vanishing white matter, medium grade myelin edema in metachromatic leukodystrophy, X-linked adrenoleukodystrophy and HMG coenzyme lyase deficiency and high grade edema in Krabbe disease, Canavan disease, hyperhomocystinemias, maple syrup urine disease and leukodystrophy with brainstem and spinal cord involvement and high lactate. (orig.)

  14. Diffusion-weighted MR imaging in leukodystrophies

    International Nuclear Information System (INIS)

    Patay, Zoltan

    2005-01-01

    Leukodystrophies are genetically determined metabolic diseases, in which the underlying biochemical abnormality interferes with the normal build-up and/or maintenance of myelin, which leads to hypo- (or arrested) myelination, or dysmyelination with resultant demyelination. Although conventional magnetic resonance imaging has significantly contributed to recent progress in the diagnostic work-up of these diseases, diffusion-weighted imaging has the potential to further improve our understanding of underlying pathological processes and their dynamics through the assessment of normal and abnormal diffusion properties of cerebral white matter. Evaluation of conventional diffusion-weighted and ADC map images allows the detection of major diffusion abnormalities and the identification of various edema types, of which the so-called myelin edema is particularly relevant to leukodystrophies. Depending on the nature of histopathological changes, stage and progression gradient of diseases, various diffusion-weighted imaging patterns may be seen in leukodystrophies. Absent or low-grade myelin edema is found in mucopolysaccharidoses, GM gangliosidoses, Zellweger disease, adrenomyeloneuropathy, L-2-hydroxyglutaric aciduria, non-ketotic hyperglycinemia, classical phenylketonuria, Van der Knaap disease and the vanishing white matter, medium grade myelin edema in metachromatic leukodystrophy, X-linked adrenoleukodystrophy and HMG coenzyme lyase deficiency and high grade edema in Krabbe disease, Canavan disease, hyperhomocystinemias, maple syrup urine disease and leukodystrophy with brainstem and spinal cord involvement and high lactate. (orig.)

  15. Diffusion weighted imaging in prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Cher Heng [The University of Texas, M D Anderson Cancer Center, Department of Diagnostic Radiology, Division of Diagnostic Imaging, Houston, TX (United States); Tan Tock Seng Hospital, Department of Diagnostic Radiology, Singapore (Singapore); Wang, Jihong [The University of Texas, M D Anderson Cancer Center, Department of Imaging Physics, Division of Diagnostic Imaging, Houston, TX (United States); Kundra, Vikas [The University of Texas, M D Anderson Cancer Center, Department of Diagnostic Radiology, Division of Diagnostic Imaging, Houston, TX (United States); The University of Texas, M D Anderson Cancer Center, Department of Experimental Diagnostic Imaging, Division of Diagnostic Imaging, Houston, TX (United States)

    2011-03-15

    Diffusion-weighted imaging has generated substantial interest in the hope that it can be developed into a robust technique to improve the accuracy of MRI for the evaluation of prostate cancer. This technique has the advantages of short acquisition times, no need for intravenous administration of contrast medium, and the ability to study diffusion of water molecules that indirectly reflects tissue cellularity. In this article, we review the existing literature on the utility of DWI in tumour detection, localisation, treatment response, limitations of the technique, how it compares with other imaging techniques, technical considerations and future directions. (orig.)

  16. MR imaging of diffuse thyroid disorders

    International Nuclear Information System (INIS)

    Inoue, Masaaki; Fujii, Koichi; Ohnishi, Takuya; Higashikawa, Motoki; Araki, Yutaka; Hamada, Tatsumi; Ishida, Osamu

    1996-01-01

    Magnetic resonance imaging was performed in 38 diffuse goiters, including 30 chronic thyroiditis and 8 Basedow disease. MR findings were analyzed as to degree of swelling, margin, internal structures including homogeneity and low intensity bands. With regard to signal intensity, thyroid-muscle-signal intensity ratios on T1 and T2-weighted images were measured in 19 normal thyroid glands, 30 chronic thyroiditis and 8 Basedow disease. Additionally thyroid-muscle-signal intensity ratios were compared between 19 hypothyroid glands and 11 euthyroid glands in chronic thyroiditis. Chronic thyroiditis tended to show lobulated margins, inhomogeneous intensity, and low intensity bands connecting with vessels or not. Basedow disease tended to display smooth margins, inhomogeneous intensity and low intensity bands connecting with vessels. Thyroid-muscle-signal intensity ratios of Basedow disease and chronic thyroiditis were significantly higher than those of normal thyroid gland at all sequences. In chronic thyroiditis thyroid-muscle-signal intensity ratios of euthyroid glands were significantly higher than those of hypothyroid glands. MR imaging could reflect pathologic features of diffuse goiters. Moreover, MR imaging is potentially contributory to speculate about thyroid function and degree of serious condition in diffuse thyroid disorders. (author)

  17. Fast imaging of mean, axial and radial diffusion kurtosis

    DEFF Research Database (Denmark)

    Hansen, Brian; Shemesh, Noam; Jespersen, Sune Nørhøj

    2016-01-01

    Abstract Diffusion kurtosis imaging (DKI) is being increasingly reported to provide sensitive biomarkers of subtle changes in tissue microstructure. However, DKI also imposes larger data requirements than diffusion tensor imaging (DTI), hence, the widespread adaptation and exploration of DKI woul...

  18. Color Histogram Diffusion for Image Enhancement

    Science.gov (United States)

    Kim, Taemin

    2011-01-01

    Various color histogram equalization (CHE) methods have been proposed to extend grayscale histogram equalization (GHE) for color images. In this paper a new method called histogram diffusion that extends the GHE method to arbitrary dimensions is proposed. Ranges in a histogram are specified as overlapping bars of uniform heights and variable widths which are proportional to their frequencies. This diagram is called the vistogram. As an alternative approach to GHE, the squared error of the vistogram from the uniform distribution is minimized. Each bar in the vistogram is approximated by a Gaussian function. Gaussian particles in the vistoram diffuse as a nonlinear autonomous system of ordinary differential equations. CHE results of color images showed that the approach is effective.

  19. Assessing human skin with diffuse reflectance spectroscopy and colorimetry

    Science.gov (United States)

    Seo, InSeok; Liu, Yang; Bargo, Paulo R.; Kollias, Nikiforos

    2012-02-01

    Colorimetry has been used as an objective measure of perceived skin color by human eye to document and score physiological responses of the skin from external insults. CIE color space values (L*, a* and b*) are the most commonly used parameters to correlate visually perceived color attributes such as L* for pigment, a* for erythema, and b* for sallowness of the skin. In this study, we investigated the relation of Lab color scale to the amount of major skin chromophores (oxy-, deoxyhemoglobin and melanin) calculated from diffuse reflectance spectroscopy. Thirty two healthy human subjects with ages from 20 to 70 years old, skin types I-VI, were recruited for the study. DRS and colorimetry measurements were taken from the left and right cheeks, and on the right upper inner arm. The melanin content calculated from 630-700 nm range of DRS measurements was shown to correlate with the lightness of skin (L*) for most skin types. For subjects with medium-to-light complexion, melanin measured at the blue part spectrum and hemoglobin interfered on the relation of lightness of the skin color to the melanin content. The sallowness of the skin that is quantified by the melanin contribution at the blue part spectrum of DRS was found to be related to b* scale. This study demonstrates the importance of documenting skin color by assessing individual skin chromophores with diffuse reflectance spectroscopy, in comparison to colorimetry assessment.

  20. Multi-compartment microscopic diffusion imaging

    OpenAIRE

    Kaden, Enrico; Kelm, Nathaniel D.; Carson, Robert P.; Does, Mark D.; Alexander, Daniel C.

    2016-01-01

    This paper introduces a multi-compartment model for microscopic diffusion anisotropy imaging. The aim is to estimate microscopic features specific to the intra- and extra-neurite compartments in nervous tissue unconfounded by the effects of fibre crossings and orientation dispersion, which are ubiquitous in the brain. The proposed MRI method is based on the Spherical Mean Technique (SMT), which factors out the neurite orientation distribution and thus provides direct estimates of the microsco...

  1. Autofluorescence and diffuse reflectance patterns in cervical spectroscopy

    Science.gov (United States)

    Marin, Nena Maribel

    Fluorescence and diffuse reflectance spectroscopy are two new optical technologies, which have shown promise to aid in the real time, non-invasive identification of cancers and precancers. Spectral patterns carry a fingerprint of scattering, absorption and fluorescence properties in tissue. Scattering, absorption and fluorescence in tissue are directly affected by biological features that are diagnostically significant, such as nuclear size, micro-vessel density, volume fraction of collagen fibers, tissue oxygenation and cell metabolism. Thus, analysis of spectral patterns can unlock a wealth of information directly related with the onset and progression of disease. Data from a Phase II clinical trial to assess the technical efficacy of fluorescence and diffuse reflectance spectroscopy acquired from 850 women at three clinical locations with two research grade optical devices is calibrated and analyzed. Tools to process and standardize spectra so that data from multiple spectrometers can be combined and analyzed are presented. Methodologies for calibration and quality assurance of optical systems are established to simplify design issues and ensure validity of data for future clinical trials. Empirically based algorithms, using multivariate statistical approaches are applied to spectra and evaluated as a clinical diagnostic tool. Physically based algorithms, using mathematical models of light propagation in tissue are presented. The presented mathematical model combines a diffusion theory in P3 approximation reflectance model and a 2-layer fluorescence model using exponential attenuation and diffusion theory. The resulting adjoint fluorescence and reflectance model extracts twelve optical properties characterizing fluorescence efficiency of cervical epithelium and stroma fluorophores, stromal hemoglobin and collagen absorption, oxygen saturation, and stromal scattering strength and shape. Validations with Monte Carlo simulations show that adjoint model extracted

  2. Imaging and assessment of diffusion coefficients by magnetic resonance

    International Nuclear Information System (INIS)

    Tintera, J.; Dezortova, M.; Hajek, M.; Fitzek, C.

    1999-01-01

    The problem of assessment of molecular diffusion by magnetic resonance is highlighted and some typical applications of diffusion imaging in the diagnosis, e.g., of cerebral ischemia, changes in patients with phenylketonuria or multiple sclerosis are discussed. The images were obtained by using diffusion weighted spin echo Echo-Planar Imaging sequence with subsequent correction of the geometrical distortion of the images and calculation of the Apparent Diffusion Coefficient map

  3. Review of diffusion tensor imaging and its application in children

    Energy Technology Data Exchange (ETDEWEB)

    Vorona, Gregory A. [Children' s Hospital of Richmond at Virginia Commonwealth University, Department of Radiology, Richmond, VA (United States); Berman, Jeffrey I. [Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States)

    2015-09-15

    Diffusion MRI is an imaging technique that uses the random motion of water to probe tissue microstructure. Diffusion tensor imaging (DTI) can quantitatively depict the organization and connectivity of white matter. Given the non-invasiveness of the technique, DTI has become a widely used tool for researchers and clinicians to examine the white matter of children. This review covers the basics of diffusion-weighted imaging and diffusion tensor imaging and discusses examples of their clinical application in children. (orig.)

  4. Real-time in vivo tissue characterization with diffuse reflectance spectroscopy during transthoracic lung biopsy: a clinical feasibility study

    NARCIS (Netherlands)

    Spliethoff, Jarich; Prevoo, Warner; Meier, Mark A.J.; de Jong, Jeroen; Evers, Daniel; Evers, Daniel J.; Sterenborg, Hendricus J.C.M.; Lucassen, Gerald; Lucassen, Gerald W.; Hendriks, Benno H.W.; Ruers, Theo J.M.

    2016-01-01

    Purpose: This study presents the first in vivo real-time tissue characterization during image-guided percutaneous lung biopsies using diffuse reflectance spectroscopy (DRS) sensing at the tip of a biopsy needle with integrated optical fibers. Experimental Design: Tissues from 21 consented patients

  5. Spatial Mapping of Translational Diffusion Coefficients Using Diffusion Tensor Imaging: A Mathematical Description.

    Science.gov (United States)

    Shetty, Anil N; Chiang, Sharon; Maletic-Savatic, Mirjana; Kasprian, Gregor; Vannucci, Marina; Lee, Wesley

    2014-01-01

    In this article, we discuss the theoretical background for diffusion weighted imaging and diffusion tensor imaging. Molecular diffusion is a random process involving thermal Brownian motion. In biological tissues, the underlying microstructures restrict the diffusion of water molecules, making diffusion directionally dependent. Water diffusion in tissue is mathematically characterized by the diffusion tensor, the elements of which contain information about the magnitude and direction of diffusion and is a function of the coordinate system. Thus, it is possible to generate contrast in tissue based primarily on diffusion effects. Expressing diffusion in terms of the measured diffusion coefficient (eigenvalue) in any one direction can lead to errors. Nowhere is this more evident than in white matter, due to the preferential orientation of myelin fibers. The directional dependency is removed by diagonalization of the diffusion tensor, which then yields a set of three eigenvalues and eigenvectors, representing the magnitude and direction of the three orthogonal axes of the diffusion ellipsoid, respectively. For example, the eigenvalue corresponding to the eigenvector along the long axis of the fiber corresponds qualitatively to diffusion with least restriction. Determination of the principal values of the diffusion tensor and various anisotropic indices provides structural information. We review the use of diffusion measurements using the modified Stejskal-Tanner diffusion equation. The anisotropy is analyzed by decomposing the diffusion tensor based on symmetrical properties describing the geometry of diffusion tensor. We further describe diffusion tensor properties in visualizing fiber tract organization of the human brain.

  6. Diffusion and perfusion imaging of bone marrow

    International Nuclear Information System (INIS)

    Biffar, Andreas; Dietrich, Olaf; Sourbron, Steven; Duerr, Hans-Roland; Reiser, Maximilian F.; Baur-Melnyk, Andrea

    2010-01-01

    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.

  7. On some applications of diffusion processes for image processing

    International Nuclear Information System (INIS)

    Morfu, S.

    2009-01-01

    We propose a new algorithm inspired by the properties of diffusion processes for image filtering. We show that purely nonlinear diffusion processes ruled by Fisher equation allows contrast enhancement and noise filtering, but involves a blurry image. By contrast, anisotropic diffusion, described by Perona and Malik algorithm, allows noise filtering and preserves the edges. We show that combining the properties of anisotropic diffusion with those of nonlinear diffusion provides a better processing tool which enables noise filtering, contrast enhancement and edge preserving.

  8. Diffusion imaging and tractography of congenital brain malformations

    International Nuclear Information System (INIS)

    Wahl, Michael; Barkovich, A.J.; Mukherjee, Pratik

    2010-01-01

    Diffusion imaging is an MRI modality that measures the microscopic molecular motion of water in order to investigate white matter microstructure. The modality has been used extensively in recent years to investigate the neuroanatomical basis of congenital brain malformations. We review the basic principles of diffusion imaging and of specific techniques, including diffusion tensor imaging (DTI) and high angular resolution diffusion imaging (HARDI). We show how DTI and HARDI, and their application to fiber tractography, has elucidated the aberrant connectivity underlying a number of congenital brain malformations. Finally, we discuss potential uses for diffusion imaging of developmental disorders in the clinical and research realms. (orig.)

  9. New imaging algorithm in diffusion tomography

    Science.gov (United States)

    Klibanov, Michael V.; Lucas, Thomas R.; Frank, Robert M.

    1997-08-01

    A novel imaging algorithm for diffusion/optical tomography is presented for the case of the time dependent diffusion equation. Numerical tests are conducted for ranges of parameters realistic for applications to an early breast cancer diagnosis using ultrafast laser pulses. This is a perturbation-like method which works for both homogeneous a heterogeneous background media. Its main innovation lies in a new approach for a novel linearized problem (LP). Such an LP is derived and reduced to a boundary value problem for a coupled system of elliptic partial differential equations. As is well known, the solution of such a system amounts to the factorization of well conditioned, sparse matrices with few non-zero entries clustered along the diagonal, which can be done very rapidly. Thus, the main advantages of this technique are that it is fast and accurate. The authors call this approach the elliptic systems method (ESM). The ESM can be extended for other data collection schemes.

  10. Sensitivity of near-infrared spectroscopy and diffuse correlation spectroscopy to brain hemodynamics: simulations and experimental findings during hypercapnia

    Science.gov (United States)

    Selb, Juliette; Boas, David A.; Chan, Suk-Tak; Evans, Karleyton C.; Buckley, Erin M.; Carp, Stefan A.

    2014-01-01

    Abstract. Near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS) are two diffuse optical technologies for brain imaging that are sensitive to changes in hemoglobin concentrations and blood flow, respectively. Measurements for both modalities are acquired on the scalp, and therefore hemodynamic processes in the extracerebral vasculature confound the interpretation of cortical hemodynamic signals. The sensitivity of NIRS to the brain versus the extracerebral tissue and the contrast-to-noise ratio (CNR) of NIRS to cerebral hemodynamic responses have been well characterized, but the same has not been evaluated for DCS. This is important to assess in order to understand their relative capabilities in measuring cerebral physiological changes. We present Monte Carlo simulations on a head model that demonstrate that the relative brain-to-scalp sensitivity is about three times higher for DCS (0.3 at 3 cm) than for NIRS (0.1 at 3 cm). However, because DCS has higher levels of noise due to photon-counting detection, the CNR is similar for both modalities in response to a physiologically realistic simulation of brain activation. Even so, we also observed higher CNR of the hemodynamic response during graded hypercapnia in adult subjects with DCS than with NIRS. PMID:25453036

  11. Sensitivity of near-infrared spectroscopy and diffuse correlation spectroscopy to brain hemodynamics: simulations and experimental findings during hypercapnia.

    Science.gov (United States)

    Selb, Juliette; Boas, David A; Chan, Suk-Tak; Evans, Karleyton C; Buckley, Erin M; Carp, Stefan A

    2014-07-01

    Near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS) are two diffuse optical technologies for brain imaging that are sensitive to changes in hemoglobin concentrations and blood flow, respectively. Measurements for both modalities are acquired on the scalp, and therefore hemodynamic processes in the extracerebral vasculature confound the interpretation of cortical hemodynamic signals. The sensitivity of NIRS to the brain versus the extracerebral tissue and the contrast-to-noise ratio (CNR) of NIRS to cerebral hemodynamic responses have been well characterized, but the same has not been evaluated for DCS. This is important to assess in order to understand their relative capabilities in measuring cerebral physiological changes. We present Monte Carlo simulations on a head model that demonstrate that the relative brain-to-scalp sensitivity is about three times higher for DCS (0.3 at 3 cm) than for NIRS (0.1 at 3 cm). However, because DCS has higher levels of noise due to photon-counting detection, the CNR is similar for both modalities in response to a physiologically realistic simulation of brain activation. Even so, we also observed higher CNR of the hemodynamic response during graded hypercapnia in adult subjects with DCS than with NIRS.

  12. A New Optical Design for Imaging Spectroscopy

    Science.gov (United States)

    Thompson, K. L.

    2002-05-01

    We present an optical design concept for imaging spectroscopy, with some advantages over current systems. The system projects monochromatic images onto the 2-D array detector(s). Faint object and crowded field spectroscopy can be reduced first using image processing techniques, then building the spectrum, unlike integral field units where one must first extract the spectra, build data cubes from these, then reconstruct the target's integrated spectral flux. Like integral field units, all photons are detected simultaneously, unlike tunable filters which must be scanned through the wavelength range of interest and therefore pay a sensitivity pentalty. Several sample designs are presented, including an instrument optimized for measuring intermediate redshift galaxy cluster velocity dispersions, one designed for near-infrared ground-based adaptive optics, and one intended for space-based rapid follow-up of transient point sources such as supernovae and gamma ray bursts.

  13. Discriminating Yogurt Microstructure Using Diffuse Reflectance Images

    DEFF Research Database (Denmark)

    Skytte, Jacob Lercke; Møller, Flemming; Abildgaard, Otto Højager Attermann

    2015-01-01

    The protein microstructure of many dairy products is of great importance for the consumers’ experience when eating the product. However, studies concerning discrimination between protein microstructures are limited. This paper presents preliminary results for discriminating different yogurt...... microstructures using hyperspectral (500-900nm) diffuse reflectance images (DRIs) – a technique potentially well suited for inline process control. Comparisons are made to quantified measures of the yogurt microstructure observed through confocal scanning laser microscopy (CSLM). The output signal from both...... modalities is evaluated on a 24 factorial design covering four common production parameters, which significantly change the chemistry and the microstructure of the yogurt. It is found that the DRIs can be as discriminative as the CSLM images in certain cases, however the performance is highly governed...

  14. Meduloblastoma: correlação entre ressonância magnética convencional, difusão e espectroscopia de prótons Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

    Directory of Open Access Journals (Sweden)

    Mariana Vieira de Melo da Fonte

    2008-12-01

    Full Text Available OBJETIVO: Correlacionar os achados de ressonância magnética convencional, difusão e espectroscopia de prótons nos meduloblastomas, e compará-los aos dados da literatura. MATERIAIS E MÉTODOS: Análise retrospectiva de exames de ressonância magnética pré-operatórios de nove pacientes na faixa pediátrica com diagnóstico histológico de meduloblastoma (oito desmoplásicos e um de células gigantes. Foram considerados dados demográficos e características do tumor como localização, característica morfológica, intensidade de sinal, realce, disseminação e achados na difusão e espectroscopia. RESULTADOS: Na maioria dos casos os tumores apresentaram epicentro no vermis cerebelar (77,8%, sendo predominantemente sólido (88,9%, com hipossinal nas seqüências ponderadas em T1 e iso/hipersinal nas seqüências ponderadas em T2 e FLAIR, realce heterogêneo (100%, sinais de disseminação/extensão tumoral (77,8% e restrição à movimentação das moléculas de água (100%. A espectroscopia de prótons pela técnica STEAM (n = 6 demonstrou redução da relação Naa/Cr (83,3% e aumento de Co/Cr (100% e mI/Cr (66,7%, e pela técnica PRESS (n = 7 evidenciou pico de lactato (57,1%. CONCLUSÃO: O conjunto dos achados macroscópicos obtidos pela ressonância magnética, somado às características bioquímicas dos meduloblastomas, têm sido úteis na tentativa de diferenciação entre os principais tumores da fossa posterior.OBJECTIVE: To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. MATERIALS AND METHODS: Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma were retrospectively reviewed, considering demographics as well as tumors characteristics

  15. Magnetic resonance imaging in diffuse brain injury

    International Nuclear Information System (INIS)

    Yokota, Hiroyuki; Yasuda, Kazuhiro; Mashiko, Kunihiro; Henmi, Hiroshi; Otsuka, Toshibumi; Kobayashi, Shiro; Nakazawa, Shozo

    1992-01-01

    Forty cases diagnosed as diffuse brain injury (DBI) were studied by magnetic resonance imaging (MRI) performed within 3 days after injury. These cases were divided into two groups, which were the concussion group and diffuse axonal injury (DAI) group established by Gennarelli. There were no findings on computerized tomography (CT) in the concussion group except for two cases which had a brain edema or subarachnoid hemorrhage. But on MRI, high intensity areas on T2 weighted imaging were demonstrated in the cerebral white matter in this group. Many lesions in this group were thought to be edemas of the cerebral white matter, because of the fact that on serial MRI, they were isointense. In mild types of DAI, the lesions on MRI were located only in the cerebral white matter, whereas, in the severe types of DAI, lesions were located in the basal ganglia, the corpus callosum, the dorsal part of the brain stem as well as in the cerebral white matter. As for CT findings, parenchymal lesions were not visualized especially in mild DAI. Our results suggested that the lesions in cerebral concussion were edemas in cerebral white matter. In mild DAI they were non-hemorrhagic contusion; and in severe DAI they were hemorrhagic contusions in the cerebral white matter, the basal ganglia, the corpus callosum or the dorsal part of the brain stem. (author)

  16. Diffusion-weighted imaging and diffusion tensor imaging of asymptomatic lumbar disc herniation.

    Science.gov (United States)

    Sakai, Toshinori; Miyagi, Ryo; Yamabe, Eiko; Fujinaga, Yasunari; N Bhatia, Nitin; Yoshioka, Hiroshi

    2014-01-01

    Diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) were performed on a healthy 31-year-old man with asymptomatic lumbar disc herniation. Although the left S1 nerve root was obviously entrapped by a herniated mass, neither DWI nor DTI showed any significant findings for the nerve root. Decreased apparent diffusion coefficient (ADC) values and increased fractional anisotropy (FA) values were found. These results are contrary to those in previously published studies of symptomatic patients, in which a combination of increased ADC and decreased FA seem to have a relationship with nerve injury and subsequent symptoms, such as leg pain or palsy. Our results seen in an asymptomatic subject suggest that the compressed nerve with no injury, such as edema, demyelination, or persistent axonal injury, may be indicated by a combination of decreased ADC and increased FA. ADC and FA could therefore be potential tools to elucidate the pathomechanism of radiculopathy.

  17. Diffusion-weighted MR imaging of the brain. 2. ed.

    International Nuclear Information System (INIS)

    Moritani, Toshio; Ekholm, Sven; Westesson, Per-Lennart

    2009-01-01

    This practical-minded text helps the radiologist and the clinician understand diffusion-weighted MR imaging. The book's 15 chapters range from basic principles to interpretation of diffusion-weighted MR imaging and specific disease. In this second edition, diffusion tensor imaging (fractional anisotropy, color map and fiber tractography) is covered and a new chapter, on ''Diffusion-Weighted Imaging of Scalp and Skull Lesions,'' is included. The volume is updated by newly added cases accompanied by radiological and pathological images along with the most recent references. It is aimed at all those who are involved in neuroimaging, including: residents, fellows, staff, as well as neurologists and neurosurgeons. Diffusion-weighted MR imaging is widely accepted as a means to identify acute infarction but also to differentiate many other pathologic conditions. Understanding diffusion-weighted imaging is important for radiologists, neurologists, neurosurgeons as well as radiology technologists. (orig.)

  18. Principles and implementation of diffusion-weighted and diffusion tensor imaging

    International Nuclear Information System (INIS)

    Roberts, Timothy P.L.; Schwartz, E.S.

    2007-01-01

    We review the physiological basis of diffusion-weighted imaging and discuss the implementation of diffusion-weighted imaging pulse sequences and the subsequent postprocessing to yield quantitative estimations of diffusion parameters. We also introduce the concept of directionality of ''apparent'' diffusion in vivo and the means of assessing such anisotropy quantitatively. This in turn leads to the methodological application of diffusion tensor imaging and the subsequent postprocessing, known as tractography. The following articles deal with the clinical applications enabled by such methodologies. (orig.)

  19. Diffusion Kurtosis Imaging of Acute Infarction: Comparison with Routine Diffusion and Follow-up MR Imaging.

    Science.gov (United States)

    Yin, Jianzhong; Sun, Haizhen; Wang, Zhiyun; Ni, Hongyan; Shen, Wen; Sun, Phillip Zhe

    2018-05-01

    Purpose To determine the relationship between diffusion-weighted imaging (DWI) and diffusion kurtosis imaging (DKI) in patients with acute stroke at admission and the tissue outcome 1 month after onset of stroke. Materials and Methods Patients with stroke underwent DWI (b values = 0, 1000 sec/mm 2 along three directions) and DKI (b values = 0, 1000, 2000 sec/mm 2 along 20 directions) within 24 hours after symptom onset and 1 month after symptom onset. For large lesions (diameter ≥ 1 cm), acute lesion volumes at DWI and DKI were compared with those at follow-up T2-weighted imaging by using Spearman correlation analysis. For small lesions (diameter the number of acute lesions at DWI and DKI and follow-up T2-weighted imaging was counted and compared by using the McNemar test. Results Thirty-seven patients (mean age, 58 years; range, 35-82 years) were included. There were 32 large lesions and 138 small lesions. For large lesions, the volumes of acute lesions on kurtosis maps showed no difference from those on 1-month follow-up T2-weighted images (P = .532), with a higher correlation coefficient than those on the apparent diffusion coefficient and mean diffusivity maps (R 2 = 0.730 vs 0.479 and 0.429). For small lesions, the number of acute lesions on DKI, but not on DWI, images was consistent with that on the follow-up T2-weighted images (P = .125). Conclusion DKI complements DWI for improved prediction of outcome of acute ischemic stroke. © RSNA, 2018.

  20. Magnetic resonance spectroscopy as an imaging method

    International Nuclear Information System (INIS)

    Bomsdorf, H.; Imme, M.; Jensen, D.; Kunz, D.; Menhardt, W.; Ottenberg, K.; Roeschmann, P.; Schmidt, K.H.; Tschendel, O.; Wieland, J.

    1990-01-01

    An experimental Magnetic Resonance (MR) system with 4 tesla flux density was set up. For that purpose a data acquisition system and RF coils for resonance frequencies up to 170 MHz were developed. Methods for image guided spectroscopy as well as spectroscopic imaging focussing on the nuclei 1 H and 13 C were developed and tested on volunteers and selected patients. The advantages of the high field strength with respect to spectroscopic studies were demonstrated. Developments of a new fast imaging technique for the acquisition of scout images as well as a method for mapping and displaying the magnetic field inhomogeneity in-vivo represent contributions to the optimisation of the experimental procedure in spectroscopic studies. Investigations on the interaction of RF radiation with the exposed tissue allowed conclusions regarding the applicability of MR methods at high field strengths. Methods for display and processing of multi-dimensional spectroscopic imaging data sets were developed and existing methods for real-time image synthesis were extended. Results achieved in the field of computer aided analysis of MR images comprised new techniques for image background detection, contour detection and automatic image interpretation as well as knowledge bases for textural representation of medical knowledge for diagnosis. (orig.) With 82 refs., 3 tabs., 75 figs [de

  1. Performances of diffusion kurtosis imaging and diffusion tensor imaging in detecting white matter abnormality in schizophrenia

    Directory of Open Access Journals (Sweden)

    Jiajia Zhu

    2015-01-01

    Full Text Available Diffusion kurtosis imaging (DKI is an extension of diffusion tensor imaging (DTI, exhibiting improved sensitivity and specificity in detecting developmental and pathological changes in neural tissues. However, little attention was paid to the performances of DKI and DTI in detecting white matter abnormality in schizophrenia. In this study, DKI and DTI were performed in 94 schizophrenia patients and 91 sex- and age-matched healthy controls. White matter integrity was assessed by fractional anisotropy (FA, mean diffusivity (MD, axial diffusivity (AD, radial diffusivity (RD, mean kurtosis (MK, axial kurtosis (AK and radial kurtosis (RK of DKI and FA, MD, AD and RD of DTI. Group differences in these parameters were compared using tract-based spatial statistics (TBSS (P  AK (20% > RK (3% and RD (37% > FA (24% > MD (21% for DKI, and RD (43% > FA (30% > MD (21% for DTI. DKI-derived diffusion parameters (RD, FA and MD were sensitive to detect abnormality in white matter regions (the corpus callosum and anterior limb of internal capsule with coherent fiber arrangement; however, the kurtosis parameters (MK and AK were sensitive to reveal abnormality in white matter regions (the juxtacortical white matter and corona radiata with complex fiber arrangement. In schizophrenia, the decreased AK suggests axonal damage; however, the increased RD indicates myelin impairment. These findings suggest that diffusion and kurtosis parameters could provide complementary information and they should be jointly used to reveal pathological changes in schizophrenia.

  2. Clinical magnetic resonance: imaging and spectroscopy

    International Nuclear Information System (INIS)

    Andrew, E.R.; Bydder, Graeme; Griffiths, John; Iles, Richard; Styles, Peter

    1990-01-01

    This book begins with a readable, comprehensive but non-mathematical introduction to the basic underlying principles of magnetic resonance. Further chapters include information on the theory and principles of MRI and MRS, the interpretation of MR images, the clinical applications and scope of MRI and MRS, practical aspects of spectroscopy and magnetic resonance, and also the practical problems associated with the siting, safety and operation of large MRI and MRS equipment. (author)

  3. Atomic Force Microscope for Imaging and Spectroscopy

    Science.gov (United States)

    Pike, W. T.; Hecht, M. H.; Anderson, M. S.; Akiyama, T.; Gautsch, S.; deRooij, N. F.; Staufer, U.; Niedermann, Ph.; Howald, L.; Mueller, D.

    2000-01-01

    We have developed, built, and tested an atomic force microscope (AFM) for extraterrestrial applications incorporating a micromachined tip array to allow for probe replacement. It is part of a microscopy station originally intended for NASA's 2001 Mars lander to identify the size, distribution, and shape of Martian dust and soil particles. As well as imaging topographically down to nanometer resolution, this instrument can be used to reveal chemical information and perform infrared and Raman spectroscopy at unprecedented resolution.

  4. Diffusing wave spectroscopy applied to material analysis and process control

    International Nuclear Information System (INIS)

    Lloyd, Christopher James

    1997-01-01

    Diffusing Wave Spectroscopy (DWS) was studied as a method of laboratory analysis of sub-micron particles, and developed as a prospective in-line, industrial, process control sensor, capable of near real-time feedback. No sample pre-treatment was required and measurement was via a non-invasive, flexible, dip in probe. DWS relies on the concept of the diffusive migration of light, as opposed to the ballistic scatter model used in conventional dynamic light scattering. The specific requirements of the optoelectronic hardware, data analysis methods and light scattering model were studied experimentally and, where practical, theoretically resulting in a novel technique of analysis of particle suspensions and emulsions of volume fractions between 0.01 and 0.4. Operation at high concentrations made the technique oblivious to dust and contamination. A pure homodyne (autodyne) experimental arrangement described was resilient to environmental disturbances, unlike many other systems which utilise optical fibres or heterodyne operation. Pilot and subsequent prototype development led to a highly accurate method of size ranking, suitable for analysis of a wide range of suspensions and emulsions. The technique was shown to operate on real industrial samples with statistical variance as low as 0.3% with minimal software processing. Whilst the application studied was the analysis of TiO 2 suspensions, a diverse range of materials including polystyrene beads, cell pastes and industrial cutting fluid emulsions were tested. Results suggest that, whilst all sizing should be comparative to suitable standards, concentration effects may be minimised and even completely modelled-out in many applications. Adhesion to the optical probe was initially a significant problem but was minimised after the evaluation and use of suitable non stick coating materials. Unexpected behaviour in the correlation in the region of short decay times led to consideration of the effects of rotational diffusion

  5. Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zonios, George [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Dimou, Aikaterini [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Galaris, Dimitrios [Laboratory of Biological Chemistry, School of Medicine, University of Ioannina, 45110 Ioannina (Greece)

    2008-01-07

    Hydrogen peroxide is an important oxidizing agent in biological systems. In dermatology, it is frequently used as topical antiseptic, it has a haemostatic function, it can cause skin blanching, and it can facilitate skin tanning. In this work, we investigated skin interaction with hydrogen peroxide, non-invasively, using diffuse reflectance spectroscopy. We observed transient changes in the oxyhaemoglobin and deoxyhaemoglobin concentrations as a result of topical application of dilute H{sub 2}O{sub 2} solutions to the skin, with changes in deoxyhaemoglobin concentration being more pronounced. Furthermore, we did not observe any appreciable changes in melanin absorption properties as well as in the skin scattering properties. We also found no evidence for production of oxidized haemoglobin forms. Our observations are consistent with an at least partial decomposition of hydrogen peroxide within the stratum corneum and epidermis, with the resulting oxygen and/or remaining hydrogen peroxide inducing vasoconstriction to dermal blood vessels and increasing haemoglobin oxygen saturation. An assessment of the effects of topical application of hydrogen peroxide to the skin may serve as the basis for the development of non-invasive techniques to measure skin antioxidant capacity and also may shed light onto skin related disorders such as vitiligo.

  6. Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

    International Nuclear Information System (INIS)

    Zonios, George; Dimou, Aikaterini; Galaris, Dimitrios

    2008-01-01

    Hydrogen peroxide is an important oxidizing agent in biological systems. In dermatology, it is frequently used as topical antiseptic, it has a haemostatic function, it can cause skin blanching, and it can facilitate skin tanning. In this work, we investigated skin interaction with hydrogen peroxide, non-invasively, using diffuse reflectance spectroscopy. We observed transient changes in the oxyhaemoglobin and deoxyhaemoglobin concentrations as a result of topical application of dilute H 2 O 2 solutions to the skin, with changes in deoxyhaemoglobin concentration being more pronounced. Furthermore, we did not observe any appreciable changes in melanin absorption properties as well as in the skin scattering properties. We also found no evidence for production of oxidized haemoglobin forms. Our observations are consistent with an at least partial decomposition of hydrogen peroxide within the stratum corneum and epidermis, with the resulting oxygen and/or remaining hydrogen peroxide inducing vasoconstriction to dermal blood vessels and increasing haemoglobin oxygen saturation. An assessment of the effects of topical application of hydrogen peroxide to the skin may serve as the basis for the development of non-invasive techniques to measure skin antioxidant capacity and also may shed light onto skin related disorders such as vitiligo

  7. Intramyocardial oxygen transport by quantitative diffuse reflectance spectroscopy in calves

    Science.gov (United States)

    Lindbergh, Tobias; Larsson, Marcus; Szabó, Zoltán; Casimir-Ahn, Henrik; Strömberg, Tomas

    2010-03-01

    Intramyocardial oxygen transport was assessed during open-chest surgery in calves by diffuse reflectance spectroscopy using a small intramuscular fiber-optic probe. The sum of hemo- and myoglobin tissue fraction and oxygen saturation, the tissue fraction and oxidation of cytochrome aa3, and the tissue fraction of methemoglobin were estimated using a calibrated empirical light transport model. Increasing the oxygen content in the inhaled gas, 21%-50%-100%, in five calves (group A) gave an increasing oxygen saturation of 19+/-4%, 24+/-5%, and 28+/-8% (panimals increased with LVAD pump speed (p<0.001, ANOVA) and with oxygen content in inhaled gas (p<0.001, ANOVA). The cytochrome aa3 oxidation level was above 96% in both group A and group B calves, including the two cases involving cardiac arrest. In conclusion, the estimated tissue fractions and oxygenation/oxidation levels of the myocardial chromophores during respiratory and hemodynamic provocations were in agreement with previously presented results, demonstrating the potential of the method.

  8. MR imaging evidence of anisotropic diffusion in the cat brain

    International Nuclear Information System (INIS)

    Moseley, M.E.; Mintorovich, J.; Cohen, Y.; Chilevitt, L.; Tsuruda, J.; Norman, D.; Weinstein, P.

    1989-01-01

    This paper discusses a study of diffusion behavior of brain water in the cat. Diffusion-weighted images, acquired with large gradient b values of 1,000-2,000 sec/mm 2 , showed no clear evidence of anisotropic water diffusion in either gray matter or basal ganglia. Large directional differences in image intensities and diffusion values were observed in cortical and deep white matter. Faster diffusion was sen when the direction of the applied diffusion gradient was parallel to the orientation of the white matter. Diffusion perpendicular to the gradient direction was significantly lower. This effect was proportional to gradient duration and strength and was seen in both pre- and immediate post-mortem images in all axial, sagittal, and coronal images

  9. Time domain diffuse optical spectroscopy: In vivo quantification of collagen in breast tissue

    Science.gov (United States)

    Taroni, Paola; Pifferi, Antonio; Quarto, Giovanna; Farina, Andrea; Ieva, Francesca; Paganoni, Anna Maria; Abbate, Francesca; Cassano, Enrico; Cubeddu, Rinaldo

    2015-05-01

    Time-resolved diffuse optical spectroscopy provides non-invasively the optical characterization of highly diffusive media, such as biological tissues. Light pulses are injected into the tissue and the effects of light propagation on re-emitted pulses are interpreted with the diffusion theory to assess simultaneously tissue absorption and reduced scattering coefficients. Performing spectral measurements, information on tissue composition and structure is derived applying the Beer law to the measured absorption and an empiric approximation to Mie theory to the reduced scattering. The absorption properties of collagen powder were preliminarily measured in the range of 600-1100 nm using a laboratory set-up for broadband time-resolved diffuse optical spectroscopy. Optical projection images were subsequently acquired in compressed breast geometry on 218 subjects, either healthy or bearing breast lesions, using a portable instrument for optical mammography that operates at 7 wavelengths selected in the range 635-1060 nm. For all subjects, tissue composition was estimated in terms of oxy- and deoxy-hemoglobin, water, lipids, and collagen. Information on tissue microscopic structure was also derived. Good correlation was obtained between mammographic breast density (a strong risk factor for breast cancer) and an optical index based on collagen content and scattering power (that accounts mostly for tissue collagen). Logistic regression applied to all optically derived parameters showed that subjects at high risk for developing breast cancer for their high breast density can effectively be identified based on collagen content and scattering parameters. Tissue composition assessed in breast lesions with a perturbative approach indicated that collagen and hemoglobin content are significantly higher in malignant lesions than in benign ones.

  10. Diffuse Reflectance Spectroscopy for Surface Measurement of Liver Pathology.

    Science.gov (United States)

    Nilsson, Jan H; Reistad, Nina; Brange, Hannes; Öberg, Carl-Fredrik; Sturesson, Christian

    2017-01-01

    Liver parenchymal injuries such as steatosis, steatohepatitis, fibrosis, and sinusoidal obstruction syndrome can lead to increased morbidity and liver failure after liver resection. Diffuse reflectance spectroscopy (DRS) is an optical measuring method that is fast, convenient, and established. DRS has previously been used on the liver with an invasive technique consisting of a needle that is inserted into the parenchyma. We developed a DRS system with a hand-held probe that is applied to the liver surface. In this study, we investigated the impact of the liver capsule on DRS measurements and whether liver surface measurements are representative of the whole liver. We also wanted to confirm that we could discriminate between tumor and liver parenchyma by DRS. The instrumentation setup consisted of a light source, a fiber-optic contact probe, and two spectrometers connected to a computer. Patients scheduled for liver resection due to hepatic malignancy were included, and DRS measurements were performed on the excised liver part with and without the liver capsule and alongside a newly cut surface. To estimate the scattering parameters and tissue chromophore volume fractions, including blood, bile, and fat, the measured diffuse reflectance spectra were applied to an analytical model. In total, 960 DRS spectra from the excised liver tissue of 18 patients were analyzed. All factors analyzed regarding tumor versus liver tissue were significantly different. When measuring through the capsule, the blood volume fraction was found to be 8.4 ± 3.5%, the lipid volume fraction was 9.9 ± 4.7%, and the bile volume fraction was 8.2 ± 4.6%. No differences could be found between surface measurements and cross-sectional measurements. In measurements with/without the liver capsule, the differences in volume fraction were 1.63% (0.75-2.77), -0.54% (-2.97 to 0.32), and -0.15% (-1.06 to 1.24) for blood, lipid, and bile, respectively. This study shows that it is possible to manage DRS

  11. New diffusion imaging method with a single acquisition sequence

    International Nuclear Information System (INIS)

    Melki, Ph.S.; Bittoun, J.; Lefevre, J.E.

    1987-01-01

    The apparent diffusion coefficient (ADC) is related to the molecular diffusion coefficient and to physiologic information: microcirculation in the capillary network, incoherent slow flow, and restricted diffusion. The authors present a new MR imaging sequence that yields computed ADC images in only one acquisition of 9-minutes with a 1.5-T imager (GE Signa). Compared to the previous method, this sequence is at least two times faster and thus can be used as a routine examination to supplement T1-, T2-, and density-weighted images. The method was assessed by measurement of the molecular diffusion in liquids, and the first clinical images obtained in neurologic diseases demonstrate its efficiency for clinical investigation. The possibility of separately imaging diffusion and perfusion is supported by an algorithm

  12. Multi-distance diffuse optical spectroscopy with a single optode via hypotrochoidal scanning.

    Science.gov (United States)

    Applegate, Matthew B; Roblyer, Darren

    2018-02-15

    Frequency-domain diffuse optical spectroscopy (FD-DOS) is an established technique capable of determining optical properties and chromophore concentrations in biological tissue. Most FD-DOS systems use either manually positioned, handheld probes or complex arrays of source and detector fibers to acquire data from many tissue locations, allowing for the generation of 2D or 3D maps of tissue. Here, we present a new method to rapidly acquire a wide range of source-detector (SD) separations by mechanically scanning a single SD pair. The source and detector fibers are mounted on a scan head that traces a hypotrochoidal pattern over the sample that, when coupled with a high-speed FD-DOS system, enables the rapid collection of dozens of SD separations for depth-resolved imaging. We demonstrate that this system has an average error of 4±2.6% in absorption and 2±1.8% in scattering across all SD separations. Additionally, by linearly translating the device, the size and location of an absorbing inhomogeneity can be determined through the generation of B-scan images in a manner conceptually analogous to ultrasound imaging. This work demonstrates the potential of single optode diffuse optical scanning for depth resolved visualization of heterogeneous biological tissues at near real-time rates.

  13. Diffusion MR Imaging of Postoperative Bilateral Acute Ischemic Optic Neuropathy

    International Nuclear Information System (INIS)

    Park, Ju Young; Lee, In Ho; Song, Chang June; Hwang, Hee Youn

    2012-01-01

    A 57-year-old woman experienced bilateral acute ischemic optic neuropathy after spine surgery. Routine MR imaging sequence, T2-weighted image, showed subtle high signal intensity on bilateral optic nerves. A contrast-enhanced T1 weighted image showed enhancement along the bilateral optic nerve sheath. Moreover, diffusion-weighted image (DWI) and an apparent diffusion coefficient map showed markedly restricted diffusion on bilateral optic nerves. Although MR findings of T2-weighted and contrast enhanced T1-weighted images may be nonspecific, the DWI finding of cytotoxic edema of bilateral optic nerves will be helpful for the diagnosis of acute ischemic optic neuropathy after spine surgery.

  14. Diffusion MR Imaging of Postoperative Bilateral Acute Ischemic Optic Neuropathy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ju Young; Lee, In Ho; Song, Chang June [Chungnam National University Hospital, Daejeon (Korea, Republic of); Hwang, Hee Youn [Eulji University Hospital, Daejeon(Korea, Republic of)

    2012-03-15

    A 57-year-old woman experienced bilateral acute ischemic optic neuropathy after spine surgery. Routine MR imaging sequence, T2-weighted image, showed subtle high signal intensity on bilateral optic nerves. A contrast-enhanced T1 weighted image showed enhancement along the bilateral optic nerve sheath. Moreover, diffusion-weighted image (DWI) and an apparent diffusion coefficient map showed markedly restricted diffusion on bilateral optic nerves. Although MR findings of T2-weighted and contrast enhanced T1-weighted images may be nonspecific, the DWI finding of cytotoxic edema of bilateral optic nerves will be helpful for the diagnosis of acute ischemic optic neuropathy after spine surgery.

  15. Diffusion and Perfusion Magnetic Resonance Imaging:Fundamentals and Advances

    OpenAIRE

    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...

  16. Assessment of sacrococcygeal pressure ulcers using diffuse correlation spectroscopy

    Science.gov (United States)

    Diaz, David; Lafontant, Alec; Neidrauer, Michael; Weingarten, Michael S.; DiMaria-Ghalili, Rose Ann; Fried, Guy W.; Rece, Julianne; Lewin, Peter A.; Zubkov, Leonid

    2016-03-01

    Microcirculation is essential for proper supply of oxygen and nutritive substances to the biological tissue and the removal of waste products of metabolism. The determination of microcirculatory blood flow (mBF) is therefore of substantial interest to clinicians for assessing tissue health; particularly in pressure ulceration and suspected deep tissue injury. The goal of this pilot clinical study was to assess deep-tissue pressure ulceration by non-invasively measuring mBF using Diffuse Correlation Spectroscopy (DCS). DCS provides information about the flow of red blood cells in the capillary network by measuring the temporal autocorrelation function of scattering light intensity. A novel optical probe was developed in order to obtain measurements under the load of the subject's body as pressure is applied (ischemia) and then released (reperfusion) on sacrococcygeal tissue in a hospital bed. Prior to loading measurements, baseline readings of the sacral region were obtained by measuring the subjects in a side-lying position. DCS measurements from the sacral region of twenty healthy volunteers have been compared to those of two patients who initially had similar non-blanchable redness. The temporal autocorrelation function of scattering light intensity of the patient whose redness later disappeared was similar to that of the average healthy subject. The second patient, whose redness developed into an advanced pressure ulcer two weeks later, had a substantial decrease in blood flow while under the loading position compared to healthy subjects. Preliminary results suggest the developed system may potentially predict whether non-blanchable redness will manifest itself as advanced ulceration or dissipate over time.

  17. Comparing near-infrared conventional diffuse reflectance spectroscopy and hyperspectral imaging for determination of the bulk properties of solid samples by multivariate regression: determination of Mooney viscosity and plasticity indices of natural rubber.

    Science.gov (United States)

    Juliano da Silva, Carlos; Pasquini, Celio

    2015-01-21

    Conventional reflectance spectroscopy (NIRS) and hyperspectral imaging (HI) in the near-infrared region (1000-2500 nm) are evaluated and compared, using, as the case study, the determination of relevant properties related to the quality of natural rubber. Mooney viscosity (MV) and plasticity indices (PI) (PI0 - original plasticity, PI30 - plasticity after accelerated aging, and PRI - the plasticity retention index after accelerated aging) of rubber were determined using multivariate regression models. Two hundred and eighty six samples of rubber were measured using conventional and hyperspectral near-infrared imaging reflectance instruments in the range of 1000-2500 nm. The sample set was split into regression (n = 191) and external validation (n = 95) sub-sets. Three instruments were employed for data acquisition: a line scanning hyperspectral camera and two conventional FT-NIR spectrometers. Sample heterogeneity was evaluated using hyperspectral images obtained with a resolution of 150 × 150 μm and principal component analysis. The probed sample area (5 cm(2); 24,000 pixels) to achieve representativeness was found to be equivalent to the average of 6 spectra for a 1 cm diameter probing circular window of one FT-NIR instrument. The other spectrophotometer can probe the whole sample in only one measurement. The results show that the rubber properties can be determined with very similar accuracy and precision by Partial Least Square (PLS) regression models regardless of whether HI-NIR or conventional FT-NIR produce the spectral datasets. The best Root Mean Square Errors of Prediction (RMSEPs) of external validation for MV, PI0, PI30, and PRI were 4.3, 1.8, 3.4, and 5.3%, respectively. Though the quantitative results provided by the three instruments can be considered equivalent, the hyperspectral imaging instrument presents a number of advantages, being about 6 times faster than conventional bulk spectrometers, producing robust spectral data by ensuring sample

  18. Field Imaging Spectroscopy. Applications in Earthquake Geology

    Science.gov (United States)

    Ragona, D.; Minster, B.; Rockwell, T. K.; Fialko, Y.; Jussila, J.; Blom, R.

    2005-12-01

    Field Imaging Spectroscopy in the visible and infrared sections of the spectrum can be used as a technique to assist paleoseismological studies. Submeter range hyperspectral images of paleoseismic excavations can assist the analyisis and interpretation of the earthquake history of a site. They also provide an excellent platform for storage of the stratigraphic and structural information collected from such a site. At the present, most field data are collected descriptively. This greatly enhances the range of information that can be recorded in the field. The descriptions are documented on hand drawn field logs and/or photomosaics constructed from individual photographs. Recently developed portable hyperspectral sensors acquire high-quality spectroscopic information at high spatial resolution (pixel size ~ 0.5 mm at 50 cm) over frequencies ranging from the visible band to short wave infrared. The new data collection and interpretation methodology that we are developing (Field Imaging Spectroscopy) makes available, for the first time, a tool to quantitatively analyze paleoseismic and stratigraphic information. The reflectance spectra of each sub-millimeter portion of the material are stored in a 3-D matrix (hyperspectral cube) that can be analyzed by visual inspection, or by using a large variety of algorithms. The reflectance spectrum is related to the chemical composition and physical properties of the surface therefore hyperspectral images are capable of revealing subtle changes in texture, composition and weathering. For paleoseismic studies, we are primarily interested in distinguishing changes between layers at a given site (spectral stratigraphy) rather than the precise composition of the layers, although this is an added benefit. We have experimented with push-broom (panoramic) portable scanners, and acquired data form portions of fault exposures and cores. These images were processed using well-known imaging processing algorithms, and the results have being

  19. Functional imaging for brain tumors (perfusion, DTI and MR spectroscopy)

    International Nuclear Information System (INIS)

    Essig, M.; Giesel, F.; Stieltjes, B.; Weber, M.A.

    2007-01-01

    This contribution considers the possibilities involved with using functional methods in magnetic resonance imaging (MRI) diagnostics for brain tumors. Of the functional methods available, we discuss perfusion MRI (PWI), diffusion MRI (DWI and DTI) and MR spectroscopy (H-MRS). In cases of brain tumor, PWI aids in grading and better differentiation in diagnostics as well as for pre-therapeutic planning. In addition, the course of treatment, both after chemo- as well as radiotherapy in combination with surgical treatment, can be optimized. PWI allows better estimates of biological activity and aggressiveness in low grade brain tumors, and in the case of WHO grade II astrocytoma showing anaplastically transformed tumor areas, allows more rapid visualization and a better prediction of the course of the disease than conventional MRI diagnostics. Diffusion MRI, due to the directional dependence of the diffusion, can illustrate the course and direction of the nerve fibers, as well as reconstructing the nerve tracts in the cerebrum, pons and cerebellum 3-dimensionally. Diffusion imaging can be used for describing brain tumors, for evaluating contralateral involvement and the course of the nerve fibers near the tumor. Due to its operator dependence, DTI based fiber tracking for defining risk structures is controversial. DWI can also not differentiate accurately between cystic and necrotic brain tumors, or between metastases and brain abscesses. H-MRS provides information on cell membrane metabolism, neuronal integrity and the function of neuronal structures, energy metabolism and the formation of tumors and brain tissue necroses. Diagnostic problems such as the differentiation between neoplastic and non-neoplastic lesions, grading cerebral glioma and distinguishing between primary brain tumors and metastases can be resolved. An additional contribution will discuss the control of the course of glial tumors after radiotherapy. (orig.)

  20. Diffusion tensor imaging in spinal cord injury

    International Nuclear Information System (INIS)

    Kamble, Ravindra B; Venkataramana, Neelam K; Naik, Arun L; Rao, Shailesh V

    2011-01-01

    To assess the feasibility of spinal tractography in patients of spinal cord injury vs a control group and to compare fractional anisotropy (FA) values between the groups. Diffusion tensor imaging (DTI) was performed in the spinal cord of 29 patients (18 patients and 11 controls). DTI was done in the cervical region if the cord injury was at the dorsal or lumbar region and in the conus region if cord injury was in the cervical or dorsal region. FA was calculated for the patients and the controls and the values were compared. The mean FA value was 0.550±0.09 in the control group and 0.367±0.14 in the patients; this difference was statistically significant (P=0.001). Spinal tractography is a feasible technique to assess the extent of spinal cord injury by FA, which is reduced in patients of spinal cord injury, suggesting possible Wallerian degeneration. In future, this technique may become a useful tool for assessing cord injury patients after stem cell therapy, with improvement in FA values indicating axonal regeneration

  1. Diffusion tensor imaging of partial intractable epilepsy

    International Nuclear Information System (INIS)

    Dumas de la Roque, Anne; Oppenheim, Catherine; Rodrigo, Sebastian; Meder, Jean-Francois; Chassoux, Francine; Devaux, Bertrand; Beuvon, Frederic; Daumas-Duport, Catherine

    2005-01-01

    Our aim was to assess the value of diffusion tensor imaging (DTI) in patients with partial intractable epilepsy. We used DTI (25 non-collinear directions) in 15 patients with a cortical lesion on conventional MRI. Fractional anisotropy (FA) was measured in the internal capsule, and in the normal-appearing white matter (WM), adjacent tothe lesion, and away from the lesion, at a set distance of 2-3 cm. In each patient, increased or decreased FA measurements were those that varied from mirror values using an arbitrary 10% threshold. Over the whole population, ipsi- and contralateral FA measurements were also compared using a Wilcoxon test (p<0.05). Over the whole population, FA was significantly reduced in the WM adjacent to and away from the lesion, whilst being normal in the internal capsule. FA was reduced by more than 10% in the WM adjacent to and distant from the lesion in 13 and 12 patients respectively. For nine of the ten patients for whom the surgical resection encompassed the limits of the lesion on conventional MRI, histological data showed WM alterations (gliosis, axonal loss, abnormal cells). DTI often reveals WM abnormalities that are undetected on conventional MRI in patients with partial intractable epilepsy. (orig.)

  2. Transitions in Structure in Oil-in-Water Emulsions As Studied by Diffusing Wave Spectroscopy

    NARCIS (Netherlands)

    Ruis, H.G.M.; Gruijthuijsen, van K.; Venema, P.; Linden, van der E.

    2007-01-01

    Transitions in structure of sodium caseinate stabilized emulsions were studied using conventional rheometry as well as diffusing wave spectroscopy (DWS). Structural differences were induced by different amounts of stabilizer, and transitions in structure were induced by acidification. Special

  3. Diffuse reflectance spectroscopy: a new guidance tool for improvement of biopsy procedures in lung malignancies

    NARCIS (Netherlands)

    Evers, Daniel; Evers, D.J.; Nachabe, R.; Klomp, H.M.; van Sandick, J.W.; Wouters, M.W.; Lucassen, G.W.; Lucassen, Gerald; Hendriks, B.H.; Wesseling, J.; Ruers, Theo J.M.

    2012-01-01

    Background: A significant number of percutaneous intrathoracic biopsy procedures result in indeterminate cytologic or histologic diagnosis in clinical practice. Diffuse reflectance spectroscopy (DRS) is an optical technique that can distinguish different tissue types on a microscopic level. DRS may

  4. Diffuse Reflectance Spectroscopy for Total Carbon Analysis of Hawaiian Soils

    Science.gov (United States)

    McDowell, M. L.; Bruland, G. L.; Deenik, J. L.; Grunwald, S.; Uchida, R.

    2010-12-01

    Accurate assessment of total carbon (Ct) content is important for fertility and nutrient management of soils, as well as for carbon sequestration studies. The non-destructive analysis of soils by diffuse reflectance spectroscopy (DRS) is a potential supplement or alternative to the traditional time-consuming and costly combustion method of Ct analysis, especially in spatial or temporal studies where sample numbers are large. We investigate the use of the visible to near-infrared (VNIR) and mid-infrared (MIR) spectra of soils coupled with chemometric analysis to determine their Ct content. Our specific focus is on Hawaiian soils of agricultural importance. Though this technique has been introduced to the soil community, it has yet to be fully tested and used in practical applications for all soil types, and this is especially true for Hawaii. In short, DRS characterizes and differentiates materials based on the variation of the light reflected by a material at certain wavelengths. This spectrum is dependent on the material’s composition, structure, and physical state. Multivariate chemometric analysis unravels the information in a set of spectra that can help predict a property such as Ct. This study benefits from the remarkably diverse soils of Hawaii. Our sample set includes 216 soil samples from 145 pedons from the main Hawaiian Islands archived at the National Soil Survey Center in Lincoln, NE, along with more than 50 newly-collected samples from Kauai, Oahu, Molokai, and Maui. In total, over 90 series from 10 of the 12 soil orders are represented. The Ct values of these samples range from < 1% - 55%. We anticipate that the diverse nature of our sample set will ensure a model with applicability to a wide variety of soils, both in Hawaii and globally. We have measured the VNIR and MIR spectra of these samples and obtained their Ct values by dry combustion. Our initial analyses are conducted using only samples obtained from the Lincoln archive. In this

  5. Comparison of the diagnostic performances of diffusion parameters in diffusion weighted imaging and diffusion tensor imaging of breast lesions

    International Nuclear Information System (INIS)

    Cakir, Ozgur; Arslan, Arzu; Inan, Nagihan; Anık, Yonca; Sarısoy, Tahsin; Gumustas, Sevtap; Akansel, Gur

    2013-01-01

    Purpose: To evaluate the diagnostic efficiency of the diffusion parameters measured by conventional diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) for discrimination of malignant breast lesions from benign lesions and the normal breast. Materials and methods: The study included 52 women with 55 breast lesions (30 malignant, 25 benign). DTI and DWI were performed complementary to dynamic contrast MRI at 3T. Apparent diffusion coefficient (ADC) of DWI, mean diffusivity (MD) and fractional anisotropy (FA) values of DTI were measured for lesions and contralateral breast parenchyma in each patient. We used b factors of 0, 50, 850, 1000 and 1500 s/mm 2 for DWI and b 0 and 1000 s/mm 2 for DTI. ADC, MD and FA values were compared between malignant and benign lesions, and the normal parenchyma by univariate and multivariate analyses. Results: Diffusion parameters showed no difference according to menopausal status in the normal breast. ADC and MD values of the malignant lesions were significantly lower than benign lesions and normal parenchyma (p = 0.001). The FA showed no statistical significance. With the cut-off values of ≤1.23 × 10 −3 mm 2 /s (b 0–1000 s/mm 2 ) and ≤1.12 × 10 −3 mm 2 /s (b 0–1500 s/mm 2 ), ADC showed 92.85% and 96.15% sensitivity; 72.22% and 73.52% PPV, respectively. With a cut-off value of ≤1.27 × 10 −3 mm 2 /s (b 1000 s/mm 2 ), MD was 100% sensitive with a PPV of 65.90%. Comparing the diagnostic performance of the parameters in DTI with DWI, we obtained similar efficiency of ADC with b values of 0,1000 and 0,1500 s/mm 2 and MD with a b value of 0, 1000 s/mm 2 (AUC = 0.82 ± 0.07). Conclusion: ADC of DWI and MD of DTI values provide significant discriminative factors for benign and malignant breast lesions. FA measurement was not discriminative. Supported with clinical and dynamic contrast MRI findings, DWI and DTI findings provide significant contribution to the final radiologic decision

  6. Comparison of the diagnostic performances of diffusion parameters in diffusion weighted imaging and diffusion tensor imaging of breast lesions

    Energy Technology Data Exchange (ETDEWEB)

    Cakir, Ozgur, E-mail: cakirozgur@hotmail.com; Arslan, Arzu, E-mail: arzu.s.arslan@gmail.com; Inan, Nagihan, E-mail: nagihaninan@yahoo.com.tr; Anık, Yonca, E-mail: yoncaanik@yahoo.com; Sarısoy, Tahsin, E-mail: htsarisoy@yahoo.com; Gumustas, Sevtap, E-mail: svtgumustas@yahoo.com; Akansel, Gur, E-mail: gakansel@gmail.com

    2013-12-01

    Purpose: To evaluate the diagnostic efficiency of the diffusion parameters measured by conventional diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) for discrimination of malignant breast lesions from benign lesions and the normal breast. Materials and methods: The study included 52 women with 55 breast lesions (30 malignant, 25 benign). DTI and DWI were performed complementary to dynamic contrast MRI at 3T. Apparent diffusion coefficient (ADC) of DWI, mean diffusivity (MD) and fractional anisotropy (FA) values of DTI were measured for lesions and contralateral breast parenchyma in each patient. We used b factors of 0, 50, 850, 1000 and 1500 s/mm{sup 2} for DWI and b 0 and 1000 s/mm{sup 2} for DTI. ADC, MD and FA values were compared between malignant and benign lesions, and the normal parenchyma by univariate and multivariate analyses. Results: Diffusion parameters showed no difference according to menopausal status in the normal breast. ADC and MD values of the malignant lesions were significantly lower than benign lesions and normal parenchyma (p = 0.001). The FA showed no statistical significance. With the cut-off values of ≤1.23 × 10{sup −3} mm{sup 2}/s (b 0–1000 s/mm{sup 2}) and ≤1.12 × 10{sup −3} mm{sup 2}/s (b 0–1500 s/mm{sup 2}), ADC showed 92.85% and 96.15% sensitivity; 72.22% and 73.52% PPV, respectively. With a cut-off value of ≤1.27 × 10{sup −3} mm{sup 2}/s (b 1000 s/mm{sup 2}), MD was 100% sensitive with a PPV of 65.90%. Comparing the diagnostic performance of the parameters in DTI with DWI, we obtained similar efficiency of ADC with b values of 0,1000 and 0,1500 s/mm{sup 2} and MD with a b value of 0, 1000 s/mm{sup 2} (AUC = 0.82 ± 0.07). Conclusion: ADC of DWI and MD of DTI values provide significant discriminative factors for benign and malignant breast lesions. FA measurement was not discriminative. Supported with clinical and dynamic contrast MRI findings, DWI and DTI findings provide significant

  7. Diffusion weighted MR imaging of acute Wernicke's encephalopathy

    International Nuclear Information System (INIS)

    Chung, Tae-Ick; Kim, Joong-Seok; Park, Soung-Kyeong; Kim, Beum-Saeng; Ahn, Kook-Jin; Yang, Dong-Won

    2003-01-01

    We report a case of Wernicke's encephalopathy in which diffusion-weighted MR images demonstrated symmetrical hyperintense lesions in the paraventricular area of the third ventricles and medial thalami. Apparent diffusion coefficient mapping showed isointensity in the aforementioned areas. Diffusion-weighted MR images may provide evidence of vasogenic edema associated with thiamine deficiency, proven in the histopathology of experimental animals. In addition, diffusion-weighted MRI has many advantages over T2 or FLARE-weighted brain MRI in detecting structural and functional abnormalities in Wernicke's encephalopathy

  8. Magnetic resonance temporal diffusion tensor spectroscopy of disordered anisotropic tissue

    DEFF Research Database (Denmark)

    Nielsen, Jonathan Scharff; Dyrby, Tim B; Lundell, Henrik

    2018-01-01

    Molecular diffusion measured with diffusion weighted MRI (DWI) offers a probe for tissue microstructure. However, inferring microstructural properties from conventional DWI data is a complex inverse problem and has to account for heterogeneity in sizes, shapes and orientations of the tissue...

  9. Magnetic resonance temporal diffusion tensor spectroscopy of disordered anisotropic tissue

    DEFF Research Database (Denmark)

    Nielsen, Jonathan Scharff; Dyrby, Tim Bjørn; Lundell, Henrik

    2018-01-01

    of the oscillating gradient spin echo (OGSE) experiment, giving a basic contrast mechanism closely linked to both the temporal diffusion spectrum and the compartment anisotropy. We demonstrate our new method on post mortem brain tissue and show that we retrieve the correct temporal diffusion tensor spectrum...

  10. Imaging features of diffuse pulmonary hemorrhage

    International Nuclear Information System (INIS)

    Schmit, M.; Vogel, W.; Horger, M.

    2006-01-01

    There are diverse etiologies of diffuse pulmonary hemorrhage, so specific diagnosis may be difficult. Conventional radiography tends to be misleading as hemoptysis may lacking in patients with hemorrhagic anemia. Diffuse pulmonary hemorrhage should be differentiated from focal pulmonary hemorrhage resulting from chronic bronchitis, bronchiectasis, active infection (tuberculosis) neoplasia, trauma, or embolism. (orig.)

  11. Diffusion in Altered Tonalite Sample Using Time Domain Diffusion Simulations in Tomographic Images Combined with Lab-scale Diffusion Experiments

    Science.gov (United States)

    Voutilainen, M.; Sardini, P.; Togneri, L.; Siitari-Kauppi, M.; Timonen, J.

    2010-12-01

    In this work an effect of rock heterogeneity on diffusion was investigated. Time domain diffusion simulations were used to compare behavior of diffusion in homogeneous and heterogeneous 3D media. Tomographic images were used as heterogeneous rock media. One altered tonalite sample from Sievi, Finland, was chosen as test case for introduced analysis procedure. Effective diffusion coefficient of tonalite sample was determined with lab-scale experiments and the same coefficient was used also for homogeneous media. Somewhat technically complicated mathematical solution for analysis of through diffusion experiment is shortly described. Computed tomography (CT) is already quite widely used in many geological, petrological, and paleontological applications when the three-dimensional (3D) structure of the material is of interest, and is an excellent method for gaining information especially about its heterogeneity, grain size, or porosity. In addition to offering means for quantitative characterization, CT provides a lot of qualitative information [1]. A through -diffusion laboratory experiment using radioactive tracer was fitted using the Time Domain Diffusion (TDD) method. This rapid particle tracking method allows simulation of the heterogeneous diffusion based on pore-scale images and local values of diffusivities [2]. As a result we found out that heterogeneity has only a small effect to diffusion coefficient and in-diffusion profile for used geometry. Also direction dependency was tested and was found to be negligible. Whereas significant difference between generally accepted value and value obtained from simulations for constant m in Archie’s law was found. [1] Voutilainen, M., Siitari-Kauppi, M., Sardini, P., and Timonen, J., (2010). On pore-space characterization of an altered tonalite by X-ray µCT and the 14C-PMMA method (in progress). [2] Sardini, P., Robinet, J., Siitari-Kauppi, M., Delay, F., and Hellmuth, K-H, (2007). On direct simulation of heterogeneous

  12. Oxygenation level and hemoglobin concentration in experimental tumor estimated by diffuse optical spectroscopy

    Science.gov (United States)

    Orlova, A. G.; Kirillin, M. Yu.; Volovetsky, A. B.; Shilyagina, N. Yu.; Sergeeva, E. A.; Golubiatnikov, G. Yu.; Turchin, I. V.

    2017-07-01

    Using diffuse optical spectroscopy the level of oxygenation and hemoglobin concentration in experimental tumor in comparison with normal muscle tissue of mice have been studied. Subcutaneously growing SKBR-3 was used as a tumor model. Continuous wave fiber probe diffuse optical spectroscopy system was employed. Optical properties extraction approach was based on diffusion approximation. Decreased blood oxygen saturation level and increased total hemoglobin content were demonstrated in the neoplasm. The main reason of such differences between tumor and norm was significant elevation of deoxyhemoglobin concentration in SKBR-3. The method can be useful for diagnosis of tumors as well as for study of blood flow parameters of tumor models with different angiogenic properties.

  13. The Polarized Radiation Imaging and Spectroscopy Mission

    CERN Document Server

    André, Philippe; Banday, Anthony; Barbosa, Domingos; Barreiro, Belen; Bartlett, James; Bartolo, Nicola; Battistelli, Elia; Battye, Richard; Bendo, George; Benoȋt, Alain; Bernard, Jean-Philippe; Bersanelli, Marco; Béthermin, Matthieu; Bielewicz, Pawel; Bonaldi, Anna; Bouchet, François; Boulanger, François; Brand, Jan; Bucher, Martin; Burigana, Carlo; Cai, Zhen-Yi; Camus, Philippe; Casas, Francisco; Casasola, Viviana; Castex, Guillaume; Challinor, Anthony; Chluba, Jens; Chon, Gayoung; Colafrancesco, Sergio; Comis, Barbara; Cuttaia, Francesco; D'Alessandro, Giuseppe; Da Silva, Antonio; Davis, Richard; de Avillez, Miguel; de Bernardis, Paolo; de Petris, Marco; de Rosa, Adriano; de Zotti, Gianfranco; Delabrouille, Jacques; Désert, François-Xavier; Dickinson, Clive; Diego, Jose Maria; Dunkley, Joanna; Enßlin, Torsten; Errard, Josquin; Falgarone, Edith; Ferreira, Pedro; Ferrière, Katia; Finelli, Fabio; Fletcher, Andrew; Fosalba, Pablo; Fuller, Gary; Galli, Silvia; Ganga, Ken; García-Bellido, Juan; Ghribi, Adnan; Giard, Martin; Giraud-Héraud, Yannick; Gonzalez-Nuevo, Joaquin; Grainge, Keith; Gruppuso, Alessandro; Hall, Alex; Hamilton, Jean-Christophe; Haverkorn, Marijke; Hernandez-Monteagudo, Carlos; Herranz, Diego; Jackson, Mark; Jaffe, Andrew; Khatri, Rishi; Kunz, Martin; Lamagna, Luca; Lattanzi, Massimiliano; Leahy, Paddy; Lesgourgues, Julien; Liguori, Michele; Liuzzo, Elisabetta; Lopez-Caniego, Marcos; Macias-Perez, Juan; Maffei, Bruno; Maino, Davide; Mangilli, Anna; Martinez-Gonzalez, Enrique; Martins, Carlos J.A.P.; Masi, Silvia; Massardi, Marcella; Matarrese, Sabino; Melchiorri, Alessandro; Melin, Jean-Baptiste; Mennella, Aniello; Mignano, Arturo; Miville-Deschênes, Marc-Antoine; Monfardini, Alessandro; Murphy, Anthony; Naselsky, Pavel; Nati, Federico; Natoli, Paolo; Negrello, Mattia; Noviello, Fabio; O'Sullivan, Créidhe; Paci, Francesco; Pagano, Luca; Paladino, Rosita; Palanque-Delabrouille, Nathalie; Paoletti, Daniela; Peiris, Hiranya; Perrotta, Francesca; Piacentini, Francesco; Piat, Michel; Piccirillo, Lucio; Pisano, Giampaolo; Polenta, Gianluca; Pollo, Agnieszka; Ponthieu, Nicolas; Remazeilles, Mathieu; Ricciardi, Sara; Roman, Matthieu; Rosset, Cyrille; Rubino-Martin, Jose-Alberto; Salatino, Maria; Schillaci, Alessandro; Shellard, Paul; Silk, Joseph; Starobinsky, Alexei; Stompor, Radek; Sunyaev, Rashid; Tartari, Andrea; Terenzi, Luca; Toffolatti, Luigi; Tomasi, Maurizio; Trappe, Neil; Tristram, Matthieu; Trombetti, Tiziana; Tucci, Marco; Van de Weijgaert, Rien; Van Tent, Bartjan; Verde, Licia; Vielva, Patricio; Wandelt, Ben; Watson, Robert; Withington, Stafford; Cabrera, Nicolas

    2014-01-01

    PRISM (Polarized Radiation Imaging and Spectroscopy Mission) was proposed to ESA in May 2013 as a large-class mission for investigating within the framework of the ESA Cosmic Vision program a set of important scientific questions that require high resolution, high sensitivity, full-sky observations of the sky emission at wavelengths ranging from millimeter-wave to the far-infrared. PRISM's main objective is to explore the distant universe, probing cosmic history from very early times until now as well as the structures, distribution of matter, and velocity flows throughout our Hubble volume. PRISM will survey the full sky in a large number of frequency bands in both intensity and polarization and will measure the absolute spectrum of sky emission more than three orders of magnitude better than COBE FIRAS. The aim of this Extended White Paper is to provide a more detailed overview of the highlights of the new science that will be made possible by PRISM

  14. Noninvasive particle sizing using camera-based diffuse reflectance spectroscopy

    DEFF Research Database (Denmark)

    Abildgaard, Otto Højager Attermann; Frisvad, Jeppe Revall; Falster, Viggo

    2016-01-01

    Diffuse reflectance measurements are useful for noninvasive inspection of optical properties such as reduced scattering and absorption coefficients. Spectroscopic analysis of these optical properties can be used for particle sizing. Systems based on optical fiber probes are commonly employed...

  15. Neutron spectroscopy of fast hydrogen diffusion in BCC transition metals

    International Nuclear Information System (INIS)

    Richter, D.; Lottner, V.

    1979-01-01

    Quasielastic neutron scattering reveals microscopic details of both the time and space development of the H-diffusion process on an atomic scale. After outlining the method on the example of PdH/sub x/, new results on the jump geometry in bcc metals are surveyed. In particular, the anomalous diffusion behavior of H in Nb, Ta, and V at elevated temperature is emphasized, where correlated jump processes are important. The influence of impurities on the H-diffusion process is demonstrated by experiments performed on NbH/sub x/ doped with nitrogen impurities, which act as trapping centers for the diffusing hydrogen. The results are discussed in terms of a two-state random walk model which includes multiple trapping and detrapping processes. The concentration and temperature dependence of the capture and escape rates of traps are obtained

  16. Imaging of postthalamic visual fiber tracts by anisotropic diffusion weighted MRI and diffusion tensor imaging: principles and applications

    International Nuclear Information System (INIS)

    Reinges, Marcus H.T.; Schoth, Felix; Coenen, Volker A.; Krings, Timo

    2004-01-01

    Diffusion weighted MRI offers the possibility to study the course of the cerebral white matter tracts. In the present manuscript, the basics, the technique and the limitations of diffusion tensor imaging and anisotropic diffusion weighted MRI are presented and their applications in various neurological and neurosurgical diseases are discussed with special emphasis on the visual system. A special focus is laid on the combination of fiber tract imaging, anatomical imaging and functional MRI for presurgical planning and intraoperative neuronavigation of lesions near the visual system

  17. Diffusion weighted imaging and diffusion tensor imaging in the evaluation of transplanted kidneys

    International Nuclear Information System (INIS)

    Palmucci, Stefano; Cappello, Giuseppina; Attinà, Giancarlo; Foti, Pietro Valerio; Siverino, Rita Olivia Anna; Roccasalva, Federica; Piccoli, Marina; Sinagra, Nunziata; Milone, Pietro; Veroux, Massimiliano; Ettorre, Giovanni Carlo

    2015-01-01

    The aim of this study is to investigate the relation between renal indexes and functional MRI in a population of kidney transplant recipients who underwent MR with diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) of the transplanted graft. Study population included 40 patients with single kidney transplant. The patients were divided into 3 groups, on the basis of creatinine clearance (CrCl) values calculated using Cockcroft-Gault formula: group A, including patients with normal renal function (CrCl ≥ 60 mL/min); group B, which refers to patients with moderate renal impairment (CrCl > 30 but <60 mL/min); and, finally, group C, which means severe renal deterioration (CrCl ≤ 30 mL/min). All patients were investigated with a 1.5 Tesla MRI scanner, acquiring DWI and DTI sequences. A Mann–Whitney U test was adopted to compare apparent diffusion coefficients (ADCs) and fractional anisotropy (FA) measurements between groups. Receiver operating characteristic (ROC) curves were created for prediction of normal renal function (group A) and renal failure (group C). Pearson correlation was performed between renal clearance and functional imaging parameter (ADC and FA), obtained for cortical and medullar regions. Mann–Whitney U test revealed a highly significant difference (p < 0.01) between patients with low CrCl (group C) and normal CrCl (group A) considering both medullar ADC and FA and cortical ADC. Regarding contiguous groups, the difference between group B and C was highly significant (p < 0.01) for medullar ADC and significant (p < 0.05) for cortical ADC and medullar FA. No difference between these groups was found considering cortical FA. Analyzing groups A and B, we found a significant difference (p < 0.05) for medullar both ADC and FA, while no difference was found for cortical ADC and FA. Strongest Pearson correlation was found between CrCl and medullar ADC (r = 0.65). For predicting normal renal function or severe renal impairment, highest

  18. Diffusion weighted MR imaging in the diagnosis of multiple sclerosis

    International Nuclear Information System (INIS)

    Hagen, T.; Schweigerer-Schroeter, G.; Wellnitz, J.; Wuerstle, T.

    2000-01-01

    Magnetic resonance (MR) imaging is one of the best methods in diagnosis of multiple sclerosis, particularly in disclosure of active demyelinating lesions. Aim of this study was to compare diffusion weighted imaging and contrast enhancement in the detection of active lesions. A MR study with a contrast enhanced T1-weighted pulse sequence with magnetization transfer presaturation and a diffusion weighted echoplanar pulse sequence (b=1000 s/mm 2 ) was performed in 17 patients (11 women, 6 men) with multiple sclerosis. 29 of 239 lesions showed an increased signal intensity in diffusion weighted imaging, 24 lesions a contrast enhancement, but only 16 lesions were visible in both pulse sequences. In patients with short clinical symptomatology significant more lesions could be detected with diffusion-weighted pulse sequence in comparison to patients with long standing symptomatology showing more lesions with contrast enhancement. Hence it is likely, that both pulse sequences detect different histopathologic changes. The early detection of demyelinating lesions in diffusion weighted imaging is attributed to the extracellular edema, however the contrast enhancement is caused by a blood brain barrier abnormality. It can be expected that diffusion weighted imaging will have a high impact on imaging of multiple sclerosis not only in therapeutic trials, but also in clinical routine. (orig.) [de

  19. Optical Spectroscopy and Imaging of Correlated Spin Orbit Phases

    Science.gov (United States)

    2016-06-14

    Unlimited UU UU UU UU 14-06-2016 15-Mar-2013 14-Mar-2016 Final Report: Optical Spectroscopy and Imaging of Correlated Spin-Orbit Phases The views...Box 12211 Research Triangle Park, NC 27709-2211 Ultrafast optical spectroscopy , nonlinear optical spectroscopy , iridates, cuprates REPORT...California Blvd. Pasadena, CA 91125 -0001 ABSTRACT Number of Papers published in peer-reviewed journals: Final Report: Optical Spectroscopy and

  20. Perspective of diffusion of imaging technologies

    International Nuclear Information System (INIS)

    Gariod, R.

    1984-10-01

    Medical imaging is dependant on the following techniques (ultra sounds, conventional radiology, digital radiology, X-ray computed tomography, NMR imaging, nuclear medicine). An overview of the forecast for world market evolution of medical imaging and the respective part taken by different techniques are presented

  1. Autofluorescence Imaging and Spectroscopy of Human Lung Cancer

    Directory of Open Access Journals (Sweden)

    Mengyan Wang

    2016-12-01

    Full Text Available Lung cancer is one of the most common cancers, with high mortality rate worldwide. Autofluorescence imaging and spectroscopy is a non-invasive, label-free, real-time technique for cancer detection. In this study, lung tissue sections excised from patients were detected by laser scan confocal microscopy and spectroscopy. The autofluorescence images demonstrated the cellular morphology and tissue structure, as well as the pathology of stained images. Based on the spectra study, it was found that the majority of the patients showed discriminating fluorescence in tumor tissues from normal tissues. Therefore, autofluorescence imaging and spectroscopy may be a potential method for aiding the diagnosis of lung cancer.

  2. Spectroscopy and Raman imaging of inhomogeneous materials

    International Nuclear Information System (INIS)

    Maslova, Olga

    2014-01-01

    This thesis is aimed at developing methodologies in Raman spectroscopy and imaging. After reviewing the statistical instruments which allow treating giant amount of data (multivariate analysis and classification), the study is applied to two families of well-known materials which are used as models for testing the limits of the implemented developments. The first family is a series of carbon materials pyrolyzed at various temperatures and exhibiting inhomogeneities at a nm scale which is suitable for Raman-X-ray diffraction combination. Another results concern the polishing effect on carbon structure. Since it is found to induce Raman artifacts leading to the overestimation of the local structural disorder, a method based on the use of the G band width is therefore proposed in order to evaluate the crystallite size in both unpolished and polished nano-graphites. The second class of materials presents inhomogeneities at higher (micrometric) scales by the example of uranium dioxide ceramics. Being well adapted in terms of spatial scale, Raman imaging is thus used for probing their surfaces. Data processing is implemented via an approach combining the multivariate (principal component) analysis and the classical fitting procedure with Lorentzian profiles. The interpretation of results is supported via electron backscattering diffraction (EBSD) analysis which enables us to distinguish the orientation effects of ceramic grains from other underlying contributions. The last ones are mainly localized at the grain boundaries, that is testified by the appearance of a specific Raman mode. Their origin seems to be caused by stoichiometric oxygen variations or impurities, as well as strain inhomogeneities. The perspectives of this work include both the implementation of other mathematical methods and in-depth analysis of UO 2 structure damaged by irradiation (anisotropic effects, role of grain boundaries). (author) [fr

  3. Single- and Multivoxel Proton Spectroscopy in Pediatric Patients With Diffuse Intrinsic Pontine Glioma

    Energy Technology Data Exchange (ETDEWEB)

    Steffen-Smith, Emilie A. [Pediatric Oncology Branch, National Cancer Institute, Center for Cancer Research, National Institutes of Health, Bethesda, Maryland (United States); Venzon, David J. [Biostatistics and Data Management Section, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Bent, Robyn S. [Pediatric Oncology Branch, National Cancer Institute, Center for Cancer Research, National Institutes of Health, Bethesda, Maryland (United States); Hipp, Sean J. [Pediatric Oncology Branch, National Cancer Institute, Center for Cancer Research, National Institutes of Health, Bethesda, Maryland (United States); Department of Pediatrics, Walter Reed National Military Medical Center, Bethesda, Maryland (United States); Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland (United States); Warren, Katherine E., E-mail: warrenk@mail.nih.gov [Pediatric Oncology Branch, National Cancer Institute, Center for Cancer Research, National Institutes of Health, Bethesda, Maryland (United States)

    2012-11-01

    Purpose: To determine the feasibility of two magnetic resonance spectroscopy (MRS) techniques for treating pediatric patients with diffuse intrinsic pontine gliomas (DIPGs) and to evaluate the relationship of metabolic profiles determined by each technique. Utility of each technique for improving patient management is also discussed. Methods and Materials: Children with DIPG (n = 36) were evaluated using single-voxel spectroscopy (SVS) and magnetic resonance spectroscopic imaging (MRSI) during the same imaging session. Patients were followed longitudinally (n = 150 total studies). Technical feasibility was defined by sufficient water and lipid suppression for detection of metabolites. Correlation of metabolic data obtained by SVS and MRSI was determined using the Spearman rank method. Metabolite ratios, including choline:N-acetyl-aspartate (Cho:NAA) and Cho:creatine (Cho:Cr), were obtained from SVS and MRSI. Results: SVS and MRSI acquisitions were feasible in >90% of studies. Maximum Cho:NAA and Cho:Cr from MRSI analysis were strongly associated with Cho:NAA and Cho:Cr obtained by SVS (r = 0.67 and 0.76, respectively). MRSI Cho:NAA values were more heterogeneous than Cho:Cr values within the same lesion, and a strong linear relationship between the range and maximum Cho:NAA values was observed. Conclusions: SVS and MRSI acquisitions were feasible, with a strong correlation in metabolic data. Both techniques may improve diagnostic evaluation and management of DIPG. SVS is recommended for global assessment of tumor metabolism before and after therapy. MRSI showed heterogeneous patterns of metabolic activity within these tumors and is recommended for planning and monitoring targeted therapies and evaluating nearby tissue for tumor invasion.

  4. Diffusion-weighted MR imaging for detection of extrahepatic cholangiocarcinoma

    International Nuclear Information System (INIS)

    Cui, Xing-Yu; Chen, Hong-Wei; Cai, Song; Bao, Jian; Tang, Qun-Feng; Wu, Li-Yuan; Fang, Xiang-Ming

    2012-01-01

    Objectives: To measure the sensitivity of diffusion-weighted imaging (DWI) and determine the most appropriate b value for DWI; to explore the correlation between the apparent diffusion coefficient (ADC) value and the degree of extrahepatic cholangiocarcinoma differentiation. Methods: Preoperative diffusion-weighted imaging and magnetic resonance examinations were performed for 31 patients with extrahepatic cholangiocarcinoma. Tumor ADC values were measured, and the signal-to-noise ratio, contrast-to-noise ratio, and signal-intensity ratio between the diffusion-weighted images with various b values as well as the T2-weighted images were calculated. Pathologically confirmed patients were pathologically graded to compare the ADC value with different b values of tumor at different degrees of differentiation, and the results were statistically analyzed by using the Friedman test. Results: A total of 29 cases of extrahepatic cholangiocarcinoma were detected by DWI. As the b value increased, tumor signal-to-noise ratio and contrast-to-noise ratio between the tumor and normal liver gradually decreased, but the tumor signal-intensity ratio gradually increased. When b = 800 s/mm 2 , contrast-to-noise ratio between tumor and normal liver, tumor signal-intensity ratio, and tumor signal-to-noise ratio of diffusion-weighted images were all higher than those of T2-weighted images; the differences were statistically significant (P 2 was the best in DWI of extrahepatic cholangiocarcinoma; the lesion ADC value declined as the degree of cancerous tissue differentiation decreased.

  5. Non-invasive detection of periodontal disease using diffuse reflectance spectroscopy: a clinical study

    Science.gov (United States)

    Prasanth, Chandra Sekhar; Betsy, Joseph; Subhash, Narayanan; Jayanthi, Jayaraj L.; Prasanthila, Janam

    2012-03-01

    In clinical diagnostic procedures, gingival inflammation is considered as the initial stage of periodontal breakdown. This is often detected clinically by bleeding on probing as it is an objective measure of inflammation. Since conventional diagnostic procedures have several inherent drawbacks, development of novel non-invasive diagnostic techniques assumes significance. This clinical study was carried out in 15 healthy volunteers and 25 patients to demonstrate the applicability of diffuse reflectance (DR) spectroscopy for quantification and discrimination of various stages of inflammatory conditions in periodontal disease. The DR spectra of diseased lesions recorded using a point monitoring system consisting of a tungsten halogen lamp and a fiber-optic spectrometer showed oxygenated hemoglobin absorption dips at 545 and 575 nm. Mean DR spectra on normalization shows marked differences between healthy and different stages of gingival inflammation. Among the various DR intensity ratios investigated, involving oxy Hb absorption peaks, the R620/R575 ratio was found to be a good parameter of gingival inflammation. In order to screen the entire diseased area and its surroundings instantaneously, DR images were recorded with an EMCCD camera at 620 and 575 nm. We have observed that using the DR image intensity ratio R620/R575 mild inflammatory tissues could be discriminated from healthy with a sensitivity of 92% and specificity of 93%, and from moderate with a sensitivity of 83% and specificity of 96%. The sensitivity and specificity obtained between moderate and severe inflammation are 82% and 76% respectively.

  6. A simple polarized-based diffused reflectance colour imaging system

    African Journals Online (AJOL)

    A simple polarized-based diffuse reflectance imaging system has been developed. The system is designed for both in vivo and in vitro imaging of agricultural specimen in the visible region. The system uses a commercial web camera and a halogen lamp that makes it relatively simple and less expensive for diagnostic ...

  7. A Riemannian scalar measure for diffusion tensor images

    NARCIS (Netherlands)

    Astola, L.J.; Fuster, A.; Florack, L.M.J.

    2010-01-01

    We study a well-known scalar quantity in Riemannian geometry, the Ricci scalar, in the context of Diffusion Tensor Imaging (DTI), which is an emerging non-invasive medical imaging modality. We derive a physical interpretation for the Ricci scalar and explore experimentally its significance in DTI.

  8. A novel image inpainting technique based on median diffusion

    Indian Academy of Sciences (India)

    numerical methods such as anisotropic diffusion and multiresolution schemes. Some steps ... Roth & Black (2005) have developed a framework for learning a generic and expressive image priors that ..... This paper presents a new approach for image inpainting by propagating median information .... J. Graphics Tools 9(1):.

  9. Cancer Metabolism and Tumor Heterogeneity: Imaging Perspectives Using MR Imaging and Spectroscopy

    Directory of Open Access Journals (Sweden)

    Gigin Lin

    2017-01-01

    Full Text Available Cancer cells reprogram their metabolism to maintain viability via genetic mutations and epigenetic alterations, expressing overall dynamic heterogeneity. The complex relaxation mechanisms of nuclear spins provide unique and convertible tissue contrasts, making magnetic resonance imaging (MRI and magnetic resonance spectroscopy (MRS pertinent imaging tools in both clinics and research. In this review, we summarized MR methods that visualize tumor characteristics and its metabolic phenotypes on an anatomical, microvascular, microstructural, microenvironmental, and metabolomics scale. The review will progress from the utilities of basic spin-relaxation contrasts in cancer imaging to more advanced imaging methods that measure tumor-distinctive parameters such as perfusion, water diffusion, magnetic susceptibility, oxygenation, acidosis, redox state, and cell death. Analytical methods to assess tumor heterogeneity are also reviewed in brief. Although the clinical utility of tumor heterogeneity from imaging is debatable, the quantification of tumor heterogeneity using functional and metabolic MR images with development of robust analytical methods and improved MR methods may offer more critical roles of tumor heterogeneity data in clinics. MRI/MRS can also provide insightful information on pharmacometabolomics, biomarker discovery, disease diagnosis and prognosis, and treatment response. With these future directions in mind, we anticipate the widespread utilization of these MR-based techniques in studying in vivo cancer biology to better address significant clinical needs.

  10. Diffusion-weighted imaging in acute demyelinating myelopathy

    International Nuclear Information System (INIS)

    Zecca, Chiara; Cereda, Carlo; Tschuor, Silvia; Staedler, Claudio; Nadarajah, Navarajah; Bassetti, Claudio L.; Gobbi, Claudio; Wetzel, Stephan; Santini, Francesco

    2012-01-01

    Diffusion-weighted imaging (DWI) has become a reference MRI technique for the evaluation of neurological disorders. Few publications have investigated the application of DWI for inflammatory demyelinating lesions. The purpose of the study was to describe diffusion-weighted imaging characteristics of acute, spinal demyelinating lesions. Six consecutive patients (two males, four females; aged 28-64 years) with acute spinal cord demyelinating lesions were studied in a prospective case series design from June 2009 to October 2010. We performed magnetic resonance imaging studies from 2 to 14 days from symptom onset on the patients with relapsing remitting multiple sclerosis (n = 3) or clinically isolated syndrome (n = 3). Main outcome measures were diffusion-weighted imaging and apparent diffusion coefficient pattern (ADC) of acute spinal cord demyelinating lesions. All spinal lesions showed a restricted diffusion pattern (DWI+/ADC-) with a 24% median ADC signal decrease. A good correlation between clinical presentation and lesion site was observed. Acute demyelinating spinal cord lesions show a uniform restricted diffusion pattern. Clinicians and neuro-radiologists should be aware that this pattern is not necessarily confirmatory for an ischaemic aetiology. (orig.)

  11. Diffusion-weighted imaging in acute demyelinating myelopathy

    Energy Technology Data Exchange (ETDEWEB)

    Zecca, Chiara; Cereda, Carlo; Tschuor, Silvia; Staedler, Claudio; Nadarajah, Navarajah; Bassetti, Claudio L.; Gobbi, Claudio [Ospedale Regionale di Lugano, Servizio di Neurologia e Neuroradiologia, Neurocenter of Southern Switzerland, Lugano (Switzerland); Wetzel, Stephan [Swiss Neuro Institute (SNI), Abteilung fuer Neuroradiologie, Hirslanden Klinik Zuerich, Zuerich (Switzerland); Santini, Francesco [University of Basel Hospital, Division of Radiological Physics, Basel (Switzerland)

    2012-06-15

    Diffusion-weighted imaging (DWI) has become a reference MRI technique for the evaluation of neurological disorders. Few publications have investigated the application of DWI for inflammatory demyelinating lesions. The purpose of the study was to describe diffusion-weighted imaging characteristics of acute, spinal demyelinating lesions. Six consecutive patients (two males, four females; aged 28-64 years) with acute spinal cord demyelinating lesions were studied in a prospective case series design from June 2009 to October 2010. We performed magnetic resonance imaging studies from 2 to 14 days from symptom onset on the patients with relapsing remitting multiple sclerosis (n = 3) or clinically isolated syndrome (n = 3). Main outcome measures were diffusion-weighted imaging and apparent diffusion coefficient pattern (ADC) of acute spinal cord demyelinating lesions. All spinal lesions showed a restricted diffusion pattern (DWI+/ADC-) with a 24% median ADC signal decrease. A good correlation between clinical presentation and lesion site was observed. Acute demyelinating spinal cord lesions show a uniform restricted diffusion pattern. Clinicians and neuro-radiologists should be aware that this pattern is not necessarily confirmatory for an ischaemic aetiology. (orig.)

  12. Diffusion weighted imaging in cystic fibrosis disease: beyond morphological imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ciet, Pierluigi [Erasmus Medical Center, Department of Radiology, Rotterdam (Netherlands); Erasmus Medical Center - Sophia Children' s Hospital, Department of Paediatrics, Respiratory Medicine and Allergology, P.O. Box 2060, Rotterdam, Zuid-Holland (Netherlands); Ca' Foncello - General Hospital, Department of Radiology, Treviso (Italy); Serra, Goffredo; Catalano, Carlo [University of Rome ' ' Sapienza' ' , Department of Radiology, Rome (Italy); Andrinopoulou, Eleni Rosalina [Erasmus Medical Center, Department of Biostatistics, Rotterdam (Netherlands); Bertolo, Silvia; Morana, Giovanni [Ca' Foncello - General Hospital, Department of Radiology, Treviso (Italy); Ros, Mirco [Ca' Foncello Hospital, Department of Pediatrics, Treviso (Italy); Colagrande, Stefano [University of Florence - Azienda Ospedaliero-Universitaria Careggi, Department of Experimental and Clinical Biomedical Sciences, Radiodiagnostic Unit n. 2, Florence (Italy); Tiddens, Harm A.W.M. [Erasmus Medical Center, Department of Radiology, Rotterdam (Netherlands); Erasmus Medical Center - Sophia Children' s Hospital, Department of Paediatrics, Respiratory Medicine and Allergology, P.O. Box 2060, Rotterdam, Zuid-Holland (Netherlands)

    2016-11-15

    To explore the feasibility of diffusion-weighted imaging (DWI) to assess inflammatory lung changes in patients with Cystic Fibrosis (CF) CF patients referred for their annual check-up had spirometry, chest-CT and MRI on the same day. MRI was performed in a 1.5 T scanner with BLADE and EPI-DWI sequences (b = 0-600 s/mm{sup 2}). End-inspiratory and end-expiratory scans were acquired in multi-row scanners. DWI was scored with an established semi-quantitative scoring system. DWI score was correlated to CT sub-scores for bronchiectasis (CF-CT{sub BE}), mucus (CF-CT{sub mucus}), total score (CF-CT{sub total-score}), FEV{sub 1}, and BMI. T-test was used to assess differences between patients with and without DWI-hotspots. Thirty-three CF patients were enrolled (mean 21 years, range 6-51, 19 female). 4 % (SD 2.6, range 1.5-12.9) of total CF-CT alterations presented DWI-hotspots. DWI-hotspots coincided with mucus plugging (60 %), consolidation (30 %) and bronchiectasis (10 %). DWI{sub total-score} correlated (all p < 0.0001) positively to CF-CT{sub BE} (r = 0.757), CF-CT{sub mucus} (r = 0.759) and CF-CT{sub total-score} (r = 0.79); and negatively to FEV{sub 1} (r = 0.688). FEV{sub 1} was significantly higher (p < 0.0001) in patients without DWI-hotspots. DWI-hotspots strongly correlated with radiological and clinical parameters of lung disease severity. Future validation studies are needed to establish the exact nature of DWI-hotspots in CF patients. (orig.)

  13. Diffusion weighted imaging in cystic fibrosis disease: beyond morphological imaging

    International Nuclear Information System (INIS)

    Ciet, Pierluigi; Serra, Goffredo; Catalano, Carlo; Andrinopoulou, Eleni Rosalina; Bertolo, Silvia; Morana, Giovanni; Ros, Mirco; Colagrande, Stefano; Tiddens, Harm A.W.M.

    2016-01-01

    To explore the feasibility of diffusion-weighted imaging (DWI) to assess inflammatory lung changes in patients with Cystic Fibrosis (CF) CF patients referred for their annual check-up had spirometry, chest-CT and MRI on the same day. MRI was performed in a 1.5 T scanner with BLADE and EPI-DWI sequences (b = 0-600 s/mm 2 ). End-inspiratory and end-expiratory scans were acquired in multi-row scanners. DWI was scored with an established semi-quantitative scoring system. DWI score was correlated to CT sub-scores for bronchiectasis (CF-CT BE ), mucus (CF-CT mucus ), total score (CF-CT total-score ), FEV 1 , and BMI. T-test was used to assess differences between patients with and without DWI-hotspots. Thirty-three CF patients were enrolled (mean 21 years, range 6-51, 19 female). 4 % (SD 2.6, range 1.5-12.9) of total CF-CT alterations presented DWI-hotspots. DWI-hotspots coincided with mucus plugging (60 %), consolidation (30 %) and bronchiectasis (10 %). DWI total-score correlated (all p < 0.0001) positively to CF-CT BE (r = 0.757), CF-CT mucus (r = 0.759) and CF-CT total-score (r = 0.79); and negatively to FEV 1 (r = 0.688). FEV 1 was significantly higher (p < 0.0001) in patients without DWI-hotspots. DWI-hotspots strongly correlated with radiological and clinical parameters of lung disease severity. Future validation studies are needed to establish the exact nature of DWI-hotspots in CF patients. (orig.)

  14. Predicting patterns of glioma recurrence using diffusion tensor imaging

    International Nuclear Information System (INIS)

    Price, Stephen J.; Pickard, John D.; Jena, Rajesh; Burnet, Neil G.; Carpenter, T.A.; Gillard, Jonathan H.

    2007-01-01

    Although multimodality therapy for high-grade gliomas is making some improvement in outcome, most patients will still die from their disease within a short time. We need tools that allow treatments to be tailored to an individual. In this study we used diffusion tensor imaging (DTI), a technique sensitive to subtle disruption of white-matter tracts due to tumour infiltration, to see if it can be used to predict patterns of glioma recurrence. In this study we imaged 26 patients with gliomas using DTI. Patients were imaged after 2 years or on symptomatic tumour recurrence. The diffusion tensor was split into its isotropic (p) and anisotropic (q) components, and these were plotted on T 2 -weighted images to show the pattern of DTI abnormality. This was compared to the pattern of recurrence. Three DTI patterns could be identified: (a) a diffuse pattern of abnormality where p exceeded q in all directions and was associated with diffuse increase in tumour size; (b) a localised pattern of abnormality where the tumour recurred in one particular direction; and (c) a pattern of minimal abnormality seen in some patients with or without evidence of recurrence. Diffusion tensor imaging is able to predict patterns of tumour recurrence and may allow better individualisation of tumour management and stratification for randomised controlled trials. (orig.)

  15. Predicting patterns of glioma recurrence using diffusion tensor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Price, Stephen J.; Pickard, John D. [University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Addenbrooke' s Hospital, Academic Neurosurgery Unit (United Kingdom); University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Addenbrooke' s Hospital, Wolfson Brain Imaging Centre, Department of Clinical Neurosciences (United Kingdom); Jena, Rajesh; Burnet, Neil G. [University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Addenbrooke' s Hospital, University Department of Oncology (United Kingdom); Carpenter, T.A. [University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Addenbrooke' s Hospital, Wolfson Brain Imaging Centre, Department of Clinical Neurosciences (United Kingdom); Gillard, Jonathan H. [University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, Addenbrooke' s Hospital, University Department of Radiology (United Kingdom)

    2007-07-15

    Although multimodality therapy for high-grade gliomas is making some improvement in outcome, most patients will still die from their disease within a short time. We need tools that allow treatments to be tailored to an individual. In this study we used diffusion tensor imaging (DTI), a technique sensitive to subtle disruption of white-matter tracts due to tumour infiltration, to see if it can be used to predict patterns of glioma recurrence. In this study we imaged 26 patients with gliomas using DTI. Patients were imaged after 2 years or on symptomatic tumour recurrence. The diffusion tensor was split into its isotropic (p) and anisotropic (q) components, and these were plotted on T{sub 2}-weighted images to show the pattern of DTI abnormality. This was compared to the pattern of recurrence. Three DTI patterns could be identified: (a) a diffuse pattern of abnormality where p exceeded q in all directions and was associated with diffuse increase in tumour size; (b) a localised pattern of abnormality where the tumour recurred in one particular direction; and (c) a pattern of minimal abnormality seen in some patients with or without evidence of recurrence. Diffusion tensor imaging is able to predict patterns of tumour recurrence and may allow better individualisation of tumour management and stratification for randomised controlled trials. (orig.)

  16. Voxel-based clustered imaging by multiparameter diffusion tensor images for glioma grading.

    Science.gov (United States)

    Inano, Rika; Oishi, Naoya; Kunieda, Takeharu; Arakawa, Yoshiki; Yamao, Yukihiro; Shibata, Sumiya; Kikuchi, Takayuki; Fukuyama, Hidenao; Miyamoto, Susumu

    2014-01-01

    Gliomas are the most common intra-axial primary brain tumour; therefore, predicting glioma grade would influence therapeutic strategies. Although several methods based on single or multiple parameters from diagnostic images exist, a definitive method for pre-operatively determining glioma grade remains unknown. We aimed to develop an unsupervised method using multiple parameters from pre-operative diffusion tensor images for obtaining a clustered image that could enable visual grading of gliomas. Fourteen patients with low-grade gliomas and 19 with high-grade gliomas underwent diffusion tensor imaging and three-dimensional T1-weighted magnetic resonance imaging before tumour resection. Seven features including diffusion-weighted imaging, fractional anisotropy, first eigenvalue, second eigenvalue, third eigenvalue, mean diffusivity and raw T2 signal with no diffusion weighting, were extracted as multiple parameters from diffusion tensor imaging. We developed a two-level clustering approach for a self-organizing map followed by the K-means algorithm to enable unsupervised clustering of a large number of input vectors with the seven features for the whole brain. The vectors were grouped by the self-organizing map as protoclusters, which were classified into the smaller number of clusters by K-means to make a voxel-based diffusion tensor-based clustered image. Furthermore, we also determined if the diffusion tensor-based clustered image was really helpful for predicting pre-operative glioma grade in a supervised manner. The ratio of each class in the diffusion tensor-based clustered images was calculated from the regions of interest manually traced on the diffusion tensor imaging space, and the common logarithmic ratio scales were calculated. We then applied support vector machine as a classifier for distinguishing between low- and high-grade gliomas. Consequently, the sensitivity, specificity, accuracy and area under the curve of receiver operating characteristic

  17. Diffusion-weighted MR imaging findings in carbon monoxide poisoning

    International Nuclear Information System (INIS)

    Teksam, M.; Casey, S.O.; Michel, E.; Liu, H.; Truwit, C.L.

    2002-01-01

    Diffusion-weighted MR imaging (DWI) of two patients with carbon monoxide (CO) poisoning demonstrated white matter and cortical hyperintensities. In one patient, the changes on the FLAIR sequence were more subtle than those on DWI. The DWI abnormality in this patient represented true restriction. In the second patient, repeated exposure to CO caused restricted diffusion. DWI may be helpful for earlier identification of the changes of acute CO poisoning. (orig.)

  18. Diffuse Reflectance Spectroscopy of Human Skin Using a Commercial Fiber Optic Spectrometer

    International Nuclear Information System (INIS)

    Atencio, J. A. Delgado; Rodriguez, M. Cunill; Montiel, S. Vazquez y; Castro, Jorge; Rodriguez, A. Cornejo; Gutierrez, J. L.; Martinez, F.; Gutierrez, B.; Orozco, E.

    2008-01-01

    Diffuse reflectance spectroscopy is a reliable and easy to implement technique in human tissue characterization. In this work we evaluate the performance of the commercial USB4000 miniature fiber optic spectrometer in the in-vivo measurement of the diffuse reflectance spectra of different healthy skin sites and lesions in a population of 54 volunteers. Results show, that this spectrometer reproduces well the typical signatures of skin spectra over the 400-1000 nm region. Remarkable spectral differences exist between lesions and normal surrounding skin. A diffusion-based model was used to simulate reflectance spectra collected by the optical probe of the system

  19. Serial diffusion-weighted imaging in MELAS

    International Nuclear Information System (INIS)

    Ohshita, T.; Oka, M.; Imon, Y.; Watanabe, C.; Katayama, S.; Yamaguchi, S.; Kajima, T.; Mimori, Y.; Nakamura, S.

    2000-01-01

    Clinical features of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) resemble those of cerebral infarcts, but the pathogenesis of infarct-like lesions is not fully understood. To characterise these infarct-like lesions, we studied two patients with MELAS using diffusion-weighted (DWI) MRI before and after stroke-like episodes and measured the apparent diffusion coefficient (ADC) in the new infarct-like lesions. These gave high signal on DWI and had much higher ADC than normal-appearing regions. The ADC remained high even 30 days after a stroke-like episode then decreased in lesions, with or without abnormality as shown by conventional MRI. We speculate that early elevation of ADC in the acute or subacute phase reflects vasogenic rather than cytotoxic edema. The ADC of the lesions, which disappeared almost completely with clinical improvement, returned to normal levels, which may reflect tissue recovery without severe damage. To our knowledge, this is the first study of DWI in MELAS. (orig.)

  20. Electrochemical Impedance Imaging via the Distribution of Diffusion Times

    Science.gov (United States)

    Song, Juhyun; Bazant, Martin Z.

    2018-03-01

    We develop a mathematical framework to analyze electrochemical impedance spectra in terms of a distribution of diffusion times (DDT) for a parallel array of random finite-length Warburg (diffusion) or Gerischer (reaction-diffusion) circuit elements. A robust DDT inversion method is presented based on complex nonlinear least squares regression with Tikhonov regularization and illustrated for three cases of nanostructured electrodes for energy conversion: (i) a carbon nanotube supercapacitor, (ii) a silicon nanowire Li-ion battery, and (iii) a porous-carbon vanadium flow battery. The results demonstrate the feasibility of nondestructive "impedance imaging" to infer microstructural statistics of random, heterogeneous materials.

  1. Comparison of nanoparticle diffusion using fluorescence correlation spectroscopy and differential dynamic microscopy within concentrated polymer solutions

    Science.gov (United States)

    Shokeen, Namita; Issa, Christopher; Mukhopadhyay, Ashis

    2017-12-01

    We studied the diffusion of nanoparticles (NPs) within aqueous entangled solutions of polyethylene oxide (PEO) by using two different optical techniques. Fluorescence correlation spectroscopy, a method widely used to investigate nanoparticle dynamics in polymer solution, was used to measure the long-time diffusion coefficient (D) of 25 nm radius particles within high molecular weight, Mw = 600 kg/mol PEO in water solutions. Differential dynamic microscopy (DDM) was used to determine the wave-vector dependent dynamics of NPs within the same polymer solutions. Our results showed good agreement between the two methods, including demonstration of normal diffusion and almost identical diffusion coefficients obtained by both techniques. The research extends the scope of DDM to study the dynamics and rheological properties of soft matter at a nanoscale. The measured diffusion coefficients followed a scaling theory, which can be explained by the coupling between polymer dynamics and NP motion.

  2. Study of the diffusion of some emulsions in the human skin by pulsed photoacoustic spectroscopy

    International Nuclear Information System (INIS)

    Lahjomri, F; Benamar, N; Chatri, E; Leblanc, R M

    2003-01-01

    We previously used pulsed photoacoustic spectroscopy (PPAS) to quantify sunscreen diffusion into human skin, and suggested a methodology to evaluate the time and the depth diffusion profile. These results were obtained by the analysis of the photoacoustic maximum response signal P max decrease, the time delay t max and the Fourier transform representation of the photoacoustic signal. In this study we present the results obtained for diffusion of four typical emulsions used in sunscreen compositions that show, for the first time, a particular behaviour for one of these emulsions due to a chemical reaction inside the skin during the diffusion process. This result provides a particularly interesting technique through the PPAS, to evaluate in situ the eventual chemical reactions that can occur during drug diffusion into human skin

  3. Diffusion tensor imaging of the human calf: Variation of inter- and intramuscle-specific diffusion parameters.

    Science.gov (United States)

    Schlaffke, Lara; Rehmann, Robert; Froeling, Martijn; Kley, Rudolf; Tegenthoff, Martin; Vorgerd, Matthias; Schmidt-Wilcke, Tobias

    2017-10-01

    To investigate to what extent inter- and intramuscular variations of diffusion parameters of human calf muscles can be explained by age, gender, muscle location, and body mass index (BMI) in a specific age group (20-35 years). Whole calf muscles of 18 healthy volunteers were evaluated. Magnetic resonance imaging (MRI) was performed using a 3T scanner and a 16-channel Torso XL coil. Diffusion-weighted images were acquired to perform fiber tractography and diffusion tensor imaging (DTI) analysis for each muscle of both legs. Fiber tractography was used to separate seven lower leg muscles. Associations between DTI parameters and confounds were evaluated. All muscles were additionally separated in seven identical segments along the z-axis to evaluate intramuscular differences in diffusion parameters. Fractional anisotropy (FA) and mean diffusivity (MD) were obtained for each muscle with low standard deviations (SDs) (SD FA : 0.01-0.02; SD MD : 0.07-0.14(10 -3 )). We found significant differences in FA values of the tibialis anterior muscle (AT) and extensor digitorum longus (EDL) muscles between men and women for whole muscle FA (two-sample t-tests; AT: P = 0.0014; EDL: P = 0.0004). We showed significant intramuscular differences in diffusion parameters between adjacent segments in most calf muscles (P < 0.001). Whereas muscle insertions showed higher (SD 0.03-0.06) than muscle bellies (SD 0.01-0.03), no relationships between FA or MD with age or BMI were found. Inter- and intramuscular variations in diffusion parameters of the calf were shown, which are not related to age or BMI in this age group. Differences between muscle belly and insertion should be considered when interpreting datasets not including whole muscles. 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1137-1148. © 2017 International Society for Magnetic Resonance in Medicine.

  4. Table-top diffuse optical imaging

    NARCIS (Netherlands)

    Sturgeon, K.A.; Bakker, L.P.

    2006-01-01

    This report describes the work done during a six months internshipat Philips Research for a Masters in Electronic and Electrical Engineering. An existing table-top tomography system for measuring lightin phantom breasts was restored. Updated software control and image reconstruction software was

  5. Diffuse reflectance spectroscopy : toward real-time quantification of steatosis in liver

    NARCIS (Netherlands)

    Evers, Daniel J.; Westerkamp, Andrie C.; Spliethoff, Jarich W.; Pully, Vishnu V.; Hompes, Daphne; Hendriks, Benno H. W.; Prevoo, Warner; van Velthuysen, Marie-Louise F.; Porte, Robert J.; Ruers, Theo J. M.

    Assessment of fatty liver grafts during orthotopic liver transplantation is a challenge due to the lack of real-time analysis options during surgery. Diffuse reflectance spectroscopy (DRS) could be a new diagnostic tool to quickly assess steatosis. Eight hundred and seventy-eight optical

  6. Conspicuity of diffuse axonal injury lesions on diffusion-weighted MR imaging

    International Nuclear Information System (INIS)

    Kinoshita, Toshibumi; Moritani, Toshio; Hiwatashi, Akio; Wang, Henry Z.; Shrier, David A.; Numaguchi, Yuji; Westesson, Per-Lennart A.

    2005-01-01

    Objective: (1) To detect diffuse axonal injury (DAI) lesions by diffusion-weighted imaging (DWI), as compared with fluid-attenuated inversion recovery (FLAIR) imaging and (2) to evaluate hemorrhagic DAI lesions by b 0 images obtained from DWI, as compared with gradient-echo (GRE) imaging. Methods: We reviewed MR images of 36 patients with a diagnosis of DAI. MR imaging was performed 20 h to 14 days (mean, 3.7 days) after traumatic brain injury. We evaluated: (1) conspicuity of lesions on DWI and FLAIR and (2) conspicuity of hemorrhage in DAI lesions on b 0 images and GRE imaging. Results: DWI clearly depicted high-signal DAI lesions. The sensitivity of DWI to lesional conspicuity in DAI lesions was almost equal to that of FLAIR. The sensitivity of b 0 images to identification of hemorrhagic DAI lesions was inferior to that of GRE. Conclusion: DWI is as useful as FLAIR in detecting DAI lesions. GRE imaging is still the superior tool for the evaluation of hemorrhagic DAI

  7. Conspicuity of diffuse axonal injury lesions on diffusion-weighted MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, Toshibumi [Department of Radiology, Division of Neuroradiology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 648, Rochester, NY 14642 (United States)]. E-mail: kino@grape.med.tottori-u.ac.jp; Moritani, Toshio [Department of Radiology, Division of Neuroradiology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 648, Rochester, NY 14642 (United States); Hiwatashi, Akio [Department of Radiology, Division of Neuroradiology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 648, Rochester, NY 14642 (United States); Wang, Henry Z. [Department of Radiology, Division of Neuroradiology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 648, Rochester, NY 14642 (United States); Shrier, David A. [Department of Radiology, Division of Neuroradiology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 648, Rochester, NY 14642 (United States); Numaguchi, Yuji [Department of Radiology, Division of Neuroradiology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 648, Rochester, NY 14642 (United States); Westesson, Per-Lennart A. [Department of Radiology, Division of Neuroradiology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 648, Rochester, NY 14642 (United States)

    2005-10-01

    Objective: (1) To detect diffuse axonal injury (DAI) lesions by diffusion-weighted imaging (DWI), as compared with fluid-attenuated inversion recovery (FLAIR) imaging and (2) to evaluate hemorrhagic DAI lesions by b{sub 0} images obtained from DWI, as compared with gradient-echo (GRE) imaging. Methods: We reviewed MR images of 36 patients with a diagnosis of DAI. MR imaging was performed 20 h to 14 days (mean, 3.7 days) after traumatic brain injury. We evaluated: (1) conspicuity of lesions on DWI and FLAIR and (2) conspicuity of hemorrhage in DAI lesions on b{sub 0} images and GRE imaging. Results: DWI clearly depicted high-signal DAI lesions. The sensitivity of DWI to lesional conspicuity in DAI lesions was almost equal to that of FLAIR. The sensitivity of b{sub 0} images to identification of hemorrhagic DAI lesions was inferior to that of GRE. Conclusion: DWI is as useful as FLAIR in detecting DAI lesions. GRE imaging is still the superior tool for the evaluation of hemorrhagic DAI.

  8. Diffusion tensor imaging of the nigrostriatal fibers in Parkinson's disease.

    Science.gov (United States)

    Zhang, Yu; Wu, I-Wei; Buckley, Shannon; Coffey, Christopher S; Foster, Eric; Mendick, Susan; Seibyl, John; Schuff, Norbert

    2015-08-01

    Parkinson's disease (PD) is histopathologically characterized by the loss of dopamine neurons in the substantia nigra pars compacta. The depletion of these neurons is thought to reduce the dopaminergic function of the nigrostriatal pathway, as well as the neural fibers that link the substantia nigra to the striatum (putamen and caudate), causing a dysregulation in striatal activity that ultimately leads to lack of movement control. Based on diffusion tensor imaging, visualizing this pathway and measuring alterations of the fiber integrity remain challenging. The objectives were to 1) develop a diffusion tensor tractography protocol for reliably tracking the nigrostriatal fibers on multicenter data; 2) test whether the integrities measured by diffusion tensor imaging of the nigrostriatal fibers are abnormal in PD; and 3) test whether abnormal integrities of the nigrostriatal fibers in PD patients are associated with the severity of motor disability and putaminal dopamine binding ratios. Diffusion tensor tractography was performed on 50 drug-naïve PD patients and 27 healthy control subjects from the international multicenter Parkinson's Progression Marker Initiative. Tractography consistently detected the nigrostriatal fibers, yielding reliable diffusion measures. Fractional anisotropy, along with radial and axial diffusivity of the nigrostriatal tract, showed systematic abnormalities in patients. In addition, variations in fractional anisotropy and radial diffusivity of the nigrostriatal tract were associated with the degree of motor deficits in PD patients. Taken together, the findings imply that the diffusion tensor imaging characteristic of the nigrostriatal tract is potentially an index for detecting and staging of early PD. © 2015 International Parkinson and Movement Disorder Society.

  9. The direct tensor solution and higher-order acquisition schemes for generalized diffusion tensor imaging

    NARCIS (Netherlands)

    Akkerman, Erik M.

    2010-01-01

    Both in diffusion tensor imaging (DTI) and in generalized diffusion tensor imaging (GDTI) the relation between the diffusion tensor and the measured apparent diffusion coefficients is given by a tensorial equation, which needs to be inverted in order to solve the diffusion tensor. The traditional

  10. Patch-based anisotropic diffusion scheme for fluorescence diffuse optical tomography--part 2: image reconstruction.

    Science.gov (United States)

    Correia, Teresa; Koch, Maximilian; Ale, Angelique; Ntziachristos, Vasilis; Arridge, Simon

    2016-02-21

    Fluorescence diffuse optical tomography (fDOT) provides 3D images of fluorescence distributions in biological tissue, which represent molecular and cellular processes. The image reconstruction problem is highly ill-posed and requires regularisation techniques to stabilise and find meaningful solutions. Quadratic regularisation tends to either oversmooth or generate very noisy reconstructions, depending on the regularisation strength. Edge preserving methods, such as anisotropic diffusion regularisation (AD), can preserve important features in the fluorescence image and smooth out noise. However, AD has limited ability to distinguish an edge from noise. We propose a patch-based anisotropic diffusion regularisation (PAD), where regularisation strength is determined by a weighted average according to the similarity between patches around voxels within a search window, instead of a simple local neighbourhood strategy. However, this method has higher computational complexity and, hence, we wavelet compress the patches (PAD-WT) to speed it up, while simultaneously taking advantage of the denoising properties of wavelet thresholding. Furthermore, structural information can be incorporated into the image reconstruction with PAD-WT to improve image quality and resolution. In this case, the weights used to average voxels in the image are calculated using the structural image, instead of the fluorescence image. The regularisation strength depends on both structural and fluorescence images, which guarantees that the method can preserve fluorescence information even when it is not structurally visible in the anatomical images. In part 1, we tested the method using a denoising problem. Here, we use simulated and in vivo mouse fDOT data to assess the algorithm performance. Our results show that the proposed PAD-WT method provides high quality and noise free images, superior to those obtained using AD.

  11. Acoustic-noise-optimized diffusion-weighted imaging.

    Science.gov (United States)

    Ott, Martin; Blaimer, Martin; Grodzki, David M; Breuer, Felix A; Roesch, Julie; Dörfler, Arnd; Heismann, Björn; Jakob, Peter M

    2015-12-01

    This work was aimed at reducing acoustic noise in diffusion-weighted MR imaging (DWI) that might reach acoustic noise levels of over 100 dB(A) in clinical practice. A diffusion-weighted readout-segmented echo-planar imaging (EPI) sequence was optimized for acoustic noise by utilizing small readout segment widths to obtain low gradient slew rates and amplitudes instead of faster k-space coverage. In addition, all other gradients were optimized for low slew rates. Volunteer and patient imaging experiments were conducted to demonstrate the feasibility of the method. Acoustic noise measurements were performed and analyzed for four different DWI measurement protocols at 1.5T and 3T. An acoustic noise reduction of up to 20 dB(A) was achieved, which corresponds to a fourfold reduction in acoustic perception. The image quality was preserved at the level of a standard single-shot (ss)-EPI sequence, with a 27-54% increase in scan time. The diffusion-weighted imaging technique proposed in this study allowed a substantial reduction in the level of acoustic noise compared to standard single-shot diffusion-weighted EPI. This is expected to afford considerably more patient comfort, but a larger study would be necessary to fully characterize the subjective changes in patient experience.

  12. Diffuse reflectance spectroscopy for the measurement of tissue oxygen saturation

    International Nuclear Information System (INIS)

    Sircan-Kucuksayan, A; Canpolat, M; Uyuklu, M

    2015-01-01

    Tissue oxygen saturation (StO 2 ) is a useful parameter for medical applications. A spectroscopic method has been developed to detect pathologic tissues, due to a lack of normal blood circulation, by measuring StO 2 . In this study, human blood samples with different levels of oxygen saturation have been prepared and spectra were acquired using an optical fiber probe to investigate the correlation between the oxygen saturation levels and the spectra. A linear correlation between the oxygen saturation and ratio of the intensities (760 nm to 790 nm) of the spectra acquired from blood samples has been found. In a validation study, oxygen saturations of the blood samples were estimated from the spectroscopic measurements with an error of 2.9%. It has also been shown that the linear dependence between the ratio and the oxygen saturation of the blood samples was valid for the blood samples with different hematocrits. Spectra were acquired from the forearms of 30 healthy volunteers to estimate StO 2 prior to, at the beginning of, after 2 min, and at the release of total vascular occlusion. The average StO 2 of a forearm before and after the two minutes occlusion was significantly different. The results suggested that optical reflectance spectroscopy is a sensitive method to estimate the StO 2 levels of human tissue. The technique developed to measure StO 2 has potential to detect ischemia in real time. (paper)

  13. Longitudinal, transcranial measurement of functional activation in the rat brain by diffuse correlation spectroscopy.

    Science.gov (United States)

    Blanco, Igor; Zirak, Peyman; Dragojević, Tanja; Castellvi, Clara; Durduran, Turgut; Justicia, Carles

    2017-10-01

    Neural activity is an important biomarker for the presence of neurodegenerative diseases, cerebrovascular alterations, and brain trauma; furthermore, it is a surrogate marker for treatment effects. These pathologies may occur and evolve in a long time-period, thus, noninvasive, transcutaneous techniques are necessary to allow a longitudinal follow-up. In the present work, we have customized noninvasive, transcutaneous, diffuse correlation spectroscopy (DCS) to localize changes in cerebral blood flow (CBF) induced by neural activity. We were able to detect changes in CBF in the somatosensory cortex by using a model of electrical forepaw stimulation in rats. The suitability of DCS measurements for longitudinal monitoring was demonstrated by performing multiple sessions with the same animals at different ages (from 6 to 18 months). In addition, functional DCS has been cross-validated by comparison with functional magnetic resonance imaging (fMRI) in the same animals in a subset of the time-points. The overall results obtained with transcutaneous DCS demonstrates that it can be utilized in longitudinal studies safely and reproducibly to locate changes in CBF induced by neural activity in the small animal brain.

  14. Functional imaging of small tissue volumes with diffuse optical tomography

    Science.gov (United States)

    Klose, Alexander D.; Hielscher, Andreas H.

    2006-03-01

    Imaging of dynamic changes in blood parameters, functional brain imaging, and tumor imaging are the most advanced application areas of diffuse optical tomography (DOT). When dealing with the image reconstruction problem one is faced with the fact that near-infrared photons, unlike X-rays, are highly scattered when they traverse biological tissue. Image reconstruction schemes are required that model the light propagation inside biological tissue and predict measurements on the tissue surface. By iteratively changing the tissue-parameters until the predictions agree with the real measurements, a spatial distribution of optical properties inside the tissue is found. The optical properties can be related to the tissue oxygenation, inflammation, or to the fluorophore concentration of a biochemical marker. If the model of light propagation is inaccurate, the reconstruction process will lead to an inaccurate result as well. Here, we focus on difficulties that are encountered when DOT is employed for functional imaging of small tissue volumes, for example, in cancer studies involving small animals, or human finger joints for early diagnosis of rheumatoid arthritis. Most of the currently employed image reconstruction methods rely on the diffusion theory that is an approximation to the equation of radiative transfer. But, in the cases of small tissue volumes and tissues that contain low scattering regions diffusion theory has been shown to be of limited applicability Therefore, we employ a light propagation model that is based on the equation of radiative transfer, which promises to overcome the limitations.

  15. Application of diffusion tensor imaging in neurosurgery; Anwendung der Diffusions-Tensor-Bildgebung in der Neurochirurgie

    Energy Technology Data Exchange (ETDEWEB)

    Saur, R. [Sektion fuer Experimentelle Kernspinresonanz des ZNS, Abt. Neuroradiologie, Universitaetsklinikum Tuebingen (Germany); Augenklinik des Universitaetsklinikums Tuebingen (Germany); Klinik fuer Psychiatrie und Psychotherapie des Universitaetsklinikums Tuebingen (Germany); Gharabaghi, A. [Klinik fuer Neurochirurgie des Universitaetsklinikums Tuebingen (Germany); Erb, M. [Sektion fuer Experimentelle Kernspinresonanz des ZNS, Abt. Neuroradiologie, Universitaetsklinikum Tuebingen (Germany)

    2007-07-01

    Knowledge about integrity and location of fibre tracts arising from eloquent cortical areas is important to plan neurosurgical interventions and to allow maximization of resection of pathological tissue while preserving vital white matter tracts. Diffusion Tensor Imaging (DTI) is so far the only method to get preoperatively an impression of the individual complexity of nerve bundles. Thereby nerve fibres are not mapped directly. They are derived indirectly by analysis of the directional distribution of diffusion of water molecules which is influenced mainly by large fibre tracts. From acquisition to reconstruction and visualisation of the fibre tracts many representational stages and working steps have to be passed. Exact knowledge about problems of Diffusion Imaging is important for interpretation of the results. Particularly, brain tumor edema, intraoperative brain shift, MR-artefacts and limitations of the mathematical models and algorithms challenge DTI-developers and applicants. (orig.)

  16. Diffusion Tensor Imaging for the Differentiation of Microangiopathy, Infarction and Perfusion-Diffusion Mismatch Lesions

    International Nuclear Information System (INIS)

    Ha, Dong Ho; Choi, Sun Seob; Kang, Myong Jin; Lee, Jin Hwa; Yoon, Seong Kuk; Nam, Kyung Jin

    2009-01-01

    This study was designed to evaluate the usefulness of diffusion tensor imaging (DTI) and the DTI indices for differentiating between microangiopathy lesions, acute infarction lesions and perfusion-diffusion mismatch areas. DTI was performed in 35 patients with the use of a 1.5 Tesla MRI system. The MRI parameters were as follows: a spin echo EPI sequence with a bvalue = 1000 s/mm 2 , 25 diffusion directions, a repetition time of 8400 msec, an echo time of 75 msec, a matrix size of 128 x 128, a FOV of 22 cm and a 4 mm slice thickness. From the diffusion tensor images, the apparent diffusion coefficient (ADC), fractional anisotropy (FA), volume ratio (VR), relative anisotropy (RA), anisotropy index (AI), exponential ADC (eADC) and magnitude diffusion coefficient (MDC) were measured for the contra-lateral normal area (28 cases), the microangiopathy lesions (10 cases), the infarction lesions (17 cases) and the perfusion-diffusion mismatch area (8 cases). As compared to the normal area, the microangiopathy lesions showed increased ADC and MDC values and decreased FA, VR, RA, AI and eADC values. The infarction lesions showed increased VR, RA and eADC values, a normal FA, a decreased AI and decreased ADC and MDC values. The mismatch area showed a similar pattern as that for the microangiopathy lesions; however, the differences were not prominent, with an increase of the ADC and MDC values and a decrease of FA, VR, RA, AI and eADC values. The DTI indices could have a role in making the differential diagnosis of microangiopathy, acute infarction and perfusion-diffusion mismatch lesions

  17. Current contribution of diffusion tensor imaging in the evaluation of diffuse axonal injury

    Directory of Open Access Journals (Sweden)

    Daphine Centola Grassi

    Full Text Available ABSTRACT Traumatic brain injury (TBI is the number one cause of death and morbidity among young adults. Moreover, survivors are frequently left with functional disabilities during the most productive years of their lives. One main aspect of TBI pathology is diffuse axonal injury, which is increasingly recognized due to its presence in 40% to 50% of all cases that require hospital admission. Diffuse axonal injury is defined as widespread axonal damage and is characterized by complete axotomy and secondary reactions due to overall axonopathy. These changes can be seen in neuroimaging studies as hemorrhagic focal areas and diffuse edema. However, the diffuse axonal injury findings are frequently under-recognized in conventional neuroimaging studies. In such scenarios, diffuse tensor imaging (DTI plays an important role because it provides further information on white matter integrity that is not obtained with standard magnetic resonance imaging sequences. Extensive reviews concerning the physics of DTI and its use in the context of TBI patients have been published, but these issues are still hazy for many allied-health professionals. Herein, we aim to review the current contribution of diverse state-of-the-art DTI analytical methods to the understanding of diffuse axonal injury pathophysiology and prognosis, to serve as a quick reference for those interested in planning new studies and who are involved in the care of TBI victims. For this purpose, a comprehensive search in Pubmed was performed using the following keywords: “traumatic brain injury”, “diffuse axonal injury”, and “diffusion tensor imaging”.

  18. Magnetic Resonance Imaging (MRI and Spectroscopy (MRS in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Uma Sharma

    2008-01-01

    Full Text Available Breast cancer is a major health problem in women and early detection is of prime importance. Breast magnetic resonance imaging (MRI provides both physical and physiologic tissue features that are useful in discriminating malignant from benign lesions. Contrast enhanced MRI is valuable for diagnosis of small tumors in dense breast and the structural and kinetic parameters improved the specificity of diagnosing benign from malignant lesions. It is a complimentary modality for preoperative staging, to follow response to therapy, to detect recurrences and for screening high risk women. Diffusion, perfusion and MR elastography have been applied to breast lesion characterization and show promise.In-vivo MR spectroscopy (MRS is a valuable method to obtain the biochemical status of normal and diseased tissues. Malignant tissues contain high concentration of choline containing compounds that can be used as a biochemical marker. MRS helps to increase the specificity of MRI in lesions larger than 1cm and to monitor the tumor response. Various MR techniques show promise primarily as adjunct to the existing standard detection techniques, and its acceptability as a screening method will increase if specificity can be improved. This review presents the progress made in different MRI and MRS techniques in breast cancer management.

  19. Magnetic Resonance Imaging (MRI and Spectroscopy (MRS in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Uma Sharma

    2008-01-01

    Full Text Available Breast cancer is a major health problem in women and early detection is of prime importance. Breast magnetic resonance imaging (MRI provides both physical and physiologic tissue features that are useful in discriminating malignant from benign lesions. Contrast enhanced MRI is valuable for diagnosis of small tumors in dense breast and the structural and kinetic parameters improved the specificity of diagnosing benign from malignant lesions. It is a complimentary modality for preoperative staging, to follow response to therapy, to detect recurrences and for screening high risk women. Diffusion, perfusion and MR elastography have been applied to breast lesion characterization and show promise. In-vivo MR spectroscopy (MRS is a valuable method to obtain the biochemical status of normal and diseased tissues. Malignant tissues contain high concentration of choline containing compounds that can be used as a biochemical marker. MRS helps to increase the specificity of MRI in lesions larger than 1cm and to monitor the tumor response. Various MR techniques show promise primarily as adjunct to the existing standard detection techniques, and its acceptability as a screening method will increase if specificity can be improved. This review presents the progress made in different MRI and MRS techniques in beast cancer management.

  20. Oriented diffusion filtering for enhancing low-quality fingerprint images

    KAUST Repository

    Gottschlich, C.; Schönlieb, C.-B.

    2012-01-01

    To enhance low-quality fingerprint images, we present a novel method that first estimates the local orientation of the fingerprint ridge and valley flow and next performs oriented diffusion filtering, followed by a locally adaptive contrast enhancement step. By applying the authors' new approach to low-quality images of the FVC2004 fingerprint databases, the authors are able to show its competitiveness with other state-of-the-art enhancement methods for fingerprints like curved Gabor filtering. A major advantage of oriented diffusion filtering over those is its computational efficiency. Combining oriented diffusion filtering with curved Gabor filters led to additional improvements and, to the best of the authors' knowledge, the lowest equal error rates achieved so far using MINDTCT and BOZORTH3 on the FVC2004 databases. The recognition performance and the computational efficiency of the method suggest to include oriented diffusion filtering as a standard image enhancement add-on module for real-time fingerprint recognition systems. In order to facilitate the reproduction of these results, an implementation of the oriented diffusion filtering for Matlab and GNU Octave is made available for download. © 2012 The Institution of Engineering and Technology.

  1. Oriented diffusion filtering for enhancing low-quality fingerprint images

    KAUST Repository

    Gottschlich, C.

    2012-01-01

    To enhance low-quality fingerprint images, we present a novel method that first estimates the local orientation of the fingerprint ridge and valley flow and next performs oriented diffusion filtering, followed by a locally adaptive contrast enhancement step. By applying the authors\\' new approach to low-quality images of the FVC2004 fingerprint databases, the authors are able to show its competitiveness with other state-of-the-art enhancement methods for fingerprints like curved Gabor filtering. A major advantage of oriented diffusion filtering over those is its computational efficiency. Combining oriented diffusion filtering with curved Gabor filters led to additional improvements and, to the best of the authors\\' knowledge, the lowest equal error rates achieved so far using MINDTCT and BOZORTH3 on the FVC2004 databases. The recognition performance and the computational efficiency of the method suggest to include oriented diffusion filtering as a standard image enhancement add-on module for real-time fingerprint recognition systems. In order to facilitate the reproduction of these results, an implementation of the oriented diffusion filtering for Matlab and GNU Octave is made available for download. © 2012 The Institution of Engineering and Technology.

  2. Fluorescence correlation spectroscopy diffusion laws in the presence of moving nanodomains

    International Nuclear Information System (INIS)

    Šachl, Radek; Hof, Martin; Bergstrand, Jan; Widengren, Jerker

    2016-01-01

    It has been shown by means of simulations that spot variation fluorescence correlation spectroscopy (sv-FCS) can be used for the identification and, to some extent, also characterization of immobile lipid nanodomains in model as well as cellular plasma membranes. However, in these simulations, the nanodomains were assumed to be stationary, whereas they actually tend to move like the surrounding lipids. In the present study, we investigated how such domain movement influences the diffusion time/spot-size dependence observed in FCS experiments, usually referred to as ‘diffusion law’ analysis. We show that domain movement might mask the effects of the ‘anomalous’ diffusion characteristics of membrane lipids or proteins predicted for stationary domains, making it difficult to identify such moving nanodomains by sv-FCS. More specifically, our simulations indicate that (i) for domains moving up to a factor of 2.25 slower than the surrounding lipids, such impeded diffusion cannot be observed and the diffusion behaviour of the proteins or lipids is indistinguishable from that of freely diffusing molecules, i.e. nanodomains are not detected; (ii) impeded protein/lipid diffusion behaviour can be observed in experiments where the radii of the detection volume are similar in size to the domain radii, the domain diffusion is about 10 times slower than that of the lipids, and the probes show a high affinity to the domains; and (iii) presence of nanodomains can only be reliably detected by diffraction limited sv-FCS when the domains move very slowly (about 200 times slower than the lipid diffusion). As nanodomains are expected to be in the range of tens of nanometres and most probes show low affinities to such domains, sv-FCS is limited to stationary domains and/or STED-FCS. However, even for that latter technique, diffusing domains smaller than 50 nm in radius are hardly detectable by FCS diffusion time/spot-size dependencies. (paper)

  3. The role of diffusion weighted magnetic resonance imaging in ...

    African Journals Online (AJOL)

    Aim of the work: To demonstrate the role of Diffusion Weighted Imaging and ADC maps in assessing normal progression of the infantile brain myelination. Patients and methods: The present work included 30 infants with normal MRI study of the brain, normal psychomotor development and normal neurological examination.

  4. Image quality transfer and applications in diffusion MRI

    DEFF Research Database (Denmark)

    Alexander, Daniel C.; Zikic, Darko; Ghosh, Aurobrata

    2017-01-01

    and the uniquely rich diffusion MRI data set from the human connectome project (HCP). Results highlight potential benefits of IQT in both brain connectivity mapping and microstructure imaging. In brain connectivity mapping, IQT reveals, from standard data sets, thin connection pathways that tractography normally...

  5. [An Improved Spectral Quaternion Interpolation Method of Diffusion Tensor Imaging].

    Science.gov (United States)

    Xu, Yonghong; Gao, Shangce; Hao, Xiaofei

    2016-04-01

    Diffusion tensor imaging(DTI)is a rapid development technology in recent years of magnetic resonance imaging.The diffusion tensor interpolation is a very important procedure in DTI image processing.The traditional spectral quaternion interpolation method revises the direction of the interpolation tensor and can preserve tensors anisotropy,but the method does not revise the size of tensors.The present study puts forward an improved spectral quaternion interpolation method on the basis of traditional spectral quaternion interpolation.Firstly,we decomposed diffusion tensors with the direction of tensors being represented by quaternion.Then we revised the size and direction of the tensor respectively according to different situations.Finally,we acquired the tensor of interpolation point by calculating the weighted average.We compared the improved method with the spectral quaternion method and the Log-Euclidean method by the simulation data and the real data.The results showed that the improved method could not only keep the monotonicity of the fractional anisotropy(FA)and the determinant of tensors,but also preserve the tensor anisotropy at the same time.In conclusion,the improved method provides a kind of important interpolation method for diffusion tensor image processing.

  6. PANDA: a pipeline toolbox for analyzing brain diffusion images.

    Science.gov (United States)

    Cui, Zaixu; Zhong, Suyu; Xu, Pengfei; He, Yong; Gong, Gaolang

    2013-01-01

    Diffusion magnetic resonance imaging (dMRI) is widely used in both scientific research and clinical practice in in-vivo studies of the human brain. While a number of post-processing packages have been developed, fully automated processing of dMRI datasets remains challenging. Here, we developed a MATLAB toolbox named "Pipeline for Analyzing braiN Diffusion imAges" (PANDA) for fully automated processing of brain diffusion images. The processing modules of a few established packages, including FMRIB Software Library (FSL), Pipeline System for Octave and Matlab (PSOM), Diffusion Toolkit and MRIcron, were employed in PANDA. Using any number of raw dMRI datasets from different subjects, in either DICOM or NIfTI format, PANDA can automatically perform a series of steps to process DICOM/NIfTI to diffusion metrics [e.g., fractional anisotropy (FA) and mean diffusivity (MD)] that are ready for statistical analysis at the voxel-level, the atlas-level and the Tract-Based Spatial Statistics (TBSS)-level and can finish the construction of anatomical brain networks for all subjects. In particular, PANDA can process different subjects in parallel, using multiple cores either in a single computer or in a distributed computing environment, thus greatly reducing the time cost when dealing with a large number of datasets. In addition, PANDA has a friendly graphical user interface (GUI), allowing the user to be interactive and to adjust the input/output settings, as well as the processing parameters. As an open-source package, PANDA is freely available at http://www.nitrc.org/projects/panda/. This novel toolbox is expected to substantially simplify the image processing of dMRI datasets and facilitate human structural connectome studies.

  7. Diffusion tensor magnetic resonance imaging of the pancreas.

    Directory of Open Access Journals (Sweden)

    Noam Nissan

    Full Text Available To develop a diffusion-tensor-imaging (DTI protocol that is sensitive to the complex diffusion and perfusion properties of the healthy and malignant pancreas tissues.Twenty-eight healthy volunteers and nine patients with pancreatic-ductal-adenocacinoma (PDAC, were scanned at 3T with T2-weighted and DTI sequences. Healthy volunteers were also scanned with multi-b diffusion-weighted-imaging (DWI, whereas a standard clinical protocol complemented the PDAC patients' scans. Image processing at pixel resolution yielded parametric maps of three directional diffusion coefficients λ1, λ2, λ3, apparent diffusion coefficient (ADC, and fractional anisotropy (FA, as well as a λ1-vector map, and a main diffusion-direction map.DTI measurements of healthy pancreatic tissue at b-values 0,500 s/mm² yielded: λ1 = (2.65±0.35×10⁻³, λ2 = (1.87±0.22×10⁻³, λ3 = (1.20±0.18×10⁻³, ADC = (1.91±0.22×10⁻³ (all in mm²/s units and FA = 0.38±0.06. Using b-values of 100,500 s/mm² led to a significant reduction in λ1, λ2, λ3 and ADC (p<.0001 and a significant increase (p<0.0001 in FA. The reduction in the diffusion coefficients suggested a contribution of a fast intra-voxel-incoherent-motion (IVIM component at b≤100 s/mm², which was confirmed by the multi-b DWI results. In PDACs, λ1, λ2, λ3 and ADC in both 0,500 s/mm² and 100,500 s/mm² b-values sets, as well as the reduction in these diffusion coefficients between the two sets, were significantly lower in comparison to the distal normal pancreatic tissue, suggesting higher cellularity and diminution of the fast-IVIM component in the cancer tissue.DTI using two reference b-values 0 and 100 s/mm² enabled characterization of the water diffusion and anisotropy of the healthy pancreas, taking into account a contribution of IVIM. The reduction in the diffusion coefficients of PDAC, as compared to normal pancreatic tissue, and the smaller change in these coefficients in PDAC

  8. Diffusion-weighted imaging of skeletal muscle lymphoma

    International Nuclear Information System (INIS)

    Surov, Alexey; Behrmann, Curd

    2014-01-01

    Muscle lymphoma (ML) is a relatively uncommon condition. On magnetic resonance imaging (MRI), ML can manifest with a broad spectrum of radiological features. The aim of this study was to demonstrate the features of DW images of muscle lymphoma (ML). In our database, ten patients (six women and four men) with ML were identified who were investigated by magnetic resonance imaging including acquisition of DW images. DW images were obtained using a multi-shot SE-EPI pulse sequence. Apparent diffusion constant (ADC) maps were also calculated. Furthermore, fusion images were generated manually from DW and HASTE or T2W images. On T2W images, all recognized lesions were hyperintense in comparison to unaffected musculature and on T1W images they were homogeneously hypointense. All lesions demonstrated low signal intensity on ADC images. The calculated ADC values ranged from 0.60 to 0.90 mm 2 s -1 (mean value 0.76 ± 0.10; median value 0.78). On fusion images, all lesions showed high signal intensity. ML demonstrated low ADC values and high signal intensity on fusion images suggesting high cellularity of the lesions. (orig.)

  9. Diffusion-weighted imaging of the musculoskeletal system in humans

    International Nuclear Information System (INIS)

    Baur, A.; Reiser, M.F.

    2000-01-01

    This article reviews the principles of diffusion-weighted imaging (DWI) and recent results in DWI of the musculoskeletal system. The potential of DWI in the diagnosis of pathology of the musculoskeletal system is discussed. DWI is a relatively new MR imaging technique that has already been established in neuroradiology, especially in the early detection of brain ischemia. The random motion of water protons on a molecular basis can be measured with DWI. To date DWI of the abdomen and of the musculoskeletal system has only been employed in scientific studies, but first results indicate that it may also be beneficial in these fields. Different diffusion characteristics have been found in normal tissues such as muscle, fat and bone marrow. Also, pathologic entities such as neoplasms, post-therapeutic soft tissue changes and inflammatory processes can be differentiated. Normal muscle shows significantly higher diffusion values than subcutaneous fat and bone marrow, due to a higher mobility of water protons within muscle. Soft tissue tumors exhibit a significantly lower diffusion value compared with post-therapeutic soft tissue changes and inflammatory processes. Necrotic tumor tissue can be distinguished from viable tumor due to significantly higher diffusion of water protons within necrotic tissue. (orig.)

  10. Small-Animal Imaging Using Diffuse Fluorescence Tomography.

    Science.gov (United States)

    Davis, Scott C; Tichauer, Kenneth M

    2016-01-01

    Diffuse fluorescence tomography (DFT) has been developed to image the spatial distribution of fluorescence-tagged tracers in living tissue. This capability facilitates the recovery of any number of functional parameters, including enzymatic activity, receptor density, blood flow, and gene expression. However, deploying DFT effectively is complex and often requires years of know-how, especially for newer mutlimodal systems that combine DFT with conventional imaging systems. In this chapter, we step through the process of using MRI-DFT imaging of a receptor-targeted tracer in small animals.

  11. Photoacoustic spectroscopy, FTIR spectra and thermal diffusivity investigation of emeraldine pellet

    International Nuclear Information System (INIS)

    Phing, T.E.; Fanny, C.Y.J.; Wan Mahmood Mat Yunus

    2001-01-01

    Photoacoustic spectra for both emeraldine base and emeraldine salt in bulk form were measured in the wavelength range of 350 nm to 700 nm. The Fourier transform Infrared spectroscopy (FTIR) have also been studied to determine the structure changes due to the protonation process. For the thermal diffusivity measurement, the open photoacoustic cell (OPC) technique has been used. It was found that the emeraldine salt exhibit higher thermal diffusivity compare to emeraldine base and this is similar to the higher conductivity characteristics of emeraldine salt. (Author)

  12. Quantification of hemoglobin and its derivatives in oral cancer diagnosis by diffuse reflectance spectroscopy

    Science.gov (United States)

    Kaniyappan, Udayakumar; Gnanatheepam, Einstein; Aruna, Prakasarao; Dornadula, Koteeswaran; Ganesan, Singaravelu

    2017-02-01

    Cancer is one of the most common threat to human beings and it increases at an alarming level around the globe. In recent years, due to the advancements in opto-electronic technology, various optical spectroscopy techniques have emerged to assess the photophysicochemical and morphological conditions of normal and malignant tissues in micro as well as in macroscopic scale. In this regard, diffuse reflectance spectroscopy is considered to be the simplest, cost effective and rapid technique in diagnosis of cancerous tissues. In the present study, the hemoglobin concentration in normal and cancerous oral tissues was quantified and subsequent statistical analysis has been carried out to verify the diagnostic potentiality of the technique.

  13. PANDA: a pipeline toolbox for analyzing brain diffusion images

    Directory of Open Access Journals (Sweden)

    Zaixu eCui

    2013-02-01

    Full Text Available Diffusion magnetic resonance imaging (dMRI is widely used in both scientific research and clinical practice in in-vivo studies of the human brain. While a number of post-processing packages have been developed, fully automated processing of dMRI datasets remains challenging. Here, we developed a MATLAB toolbox named Pipeline for Analyzing braiN Diffusion imAges (PANDA for fully automated processing of brain diffusion images. The processing modules of a few established packages, including FMRIB Software Library (FSL, Pipeline System for Octave and Matlab (PSOM, Diffusion Toolkit and MRIcron, were employed in PANDA. Using any number of raw dMRI datasets from different subjects, in either DICOM or NIfTI format, PANDA can automatically perform a series of steps to process DICOM/NIfTI to diffusion metrics (e.g., FA and MD that are ready for statistical analysis at the voxel-level, the atlas-level and the Tract-Based Spatial Statistics (TBSS-level and can finish the construction of anatomical brain networks for all subjects. In particular, PANDA can process different subjects in parallel, using multiple cores either in a single computer or in a distributed computing environment, thus greatly reducing the time cost when dealing with a large number of datasets. In addition, PANDA has a friendly graphical user interface (GUI, allowing the user to be interactive and to adjust the input/output settings, as well as the processing parameters. As an open-source package, PANDA is freely available at http://www.nitrc.org/projects/panda/. This novel toolbox is expected to substantially simplify the image processing of dMRI datasets and facilitate human structural connectome studies.

  14. Assessment of tissue heterogeneity using diffusion tensor and diffusion kurtosis imaging for grading gliomas

    Energy Technology Data Exchange (ETDEWEB)

    Raja, Rajikha; Sinha, Neelam [International Institute of Information Technology-Bangalore, Bangalore (India); Saini, Jitender; Mahadevan, Anita; Rao, K.V.L. Narasinga; Swaminathan, Aarthi [National Institute of Mental Health and Neurosciences, Bangalore (India)

    2016-12-15

    In this work, we aim to assess the significance of diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) parameters in grading gliomas. Retrospective studies were performed on 53 subjects with gliomas belonging to WHO grade II (n = 19), grade III (n = 20) and grade IV (n = 14). Expert marked regions of interest (ROIs) covering the tumour on T2-weighted images. Statistical texture measures such as entropy and busyness calculated over ROIs on diffusion parametric maps were used to assess the tumour heterogeneity. Additionally, we propose a volume heterogeneity index derived from cross correlation (CC) analysis as a tool for grading gliomas. The texture measures were compared between grades by performing the Mann-Whitney test followed by receiver operating characteristic (ROC) analysis for evaluating diagnostic accuracy. Entropy, busyness and volume heterogeneity index for all diffusion parameters except fractional anisotropy and anisotropy of kurtosis showed significant differences between grades. The Mann-Whitney test on mean diffusivity (MD), among DTI parameters, resulted in the highest discriminability with values of P = 0.029 (0.0421) for grade II vs. III and P = 0.0312 (0.0415) for III vs. IV for entropy (busyness). In DKI, mean kurtosis (MK) showed the highest discriminability, P = 0.018 (0.038) for grade II vs. III and P = 0.022 (0.04) for III vs. IV for entropy (busyness). Results of CC analysis illustrate the existence of homogeneity in volume (uniformity across slices) for lower grades, as compared to higher grades. Hypothesis testing performed on volume heterogeneity index showed P values of 0.0002 (0.0001) and 0.0003 (0.0003) between grades II vs. III and III vs. IV, respectively, for MD (MK). In summary, the studies demonstrated great potential towards automating grading gliomas by employing tumour heterogeneity measures on DTI and DKI parameters. (orig.)

  15. Assessment of tissue heterogeneity using diffusion tensor and diffusion kurtosis imaging for grading gliomas

    International Nuclear Information System (INIS)

    Raja, Rajikha; Sinha, Neelam; Saini, Jitender; Mahadevan, Anita; Rao, K.V.L. Narasinga; Swaminathan, Aarthi

    2016-01-01

    In this work, we aim to assess the significance of diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) parameters in grading gliomas. Retrospective studies were performed on 53 subjects with gliomas belonging to WHO grade II (n = 19), grade III (n = 20) and grade IV (n = 14). Expert marked regions of interest (ROIs) covering the tumour on T2-weighted images. Statistical texture measures such as entropy and busyness calculated over ROIs on diffusion parametric maps were used to assess the tumour heterogeneity. Additionally, we propose a volume heterogeneity index derived from cross correlation (CC) analysis as a tool for grading gliomas. The texture measures were compared between grades by performing the Mann-Whitney test followed by receiver operating characteristic (ROC) analysis for evaluating diagnostic accuracy. Entropy, busyness and volume heterogeneity index for all diffusion parameters except fractional anisotropy and anisotropy of kurtosis showed significant differences between grades. The Mann-Whitney test on mean diffusivity (MD), among DTI parameters, resulted in the highest discriminability with values of P = 0.029 (0.0421) for grade II vs. III and P = 0.0312 (0.0415) for III vs. IV for entropy (busyness). In DKI, mean kurtosis (MK) showed the highest discriminability, P = 0.018 (0.038) for grade II vs. III and P = 0.022 (0.04) for III vs. IV for entropy (busyness). Results of CC analysis illustrate the existence of homogeneity in volume (uniformity across slices) for lower grades, as compared to higher grades. Hypothesis testing performed on volume heterogeneity index showed P values of 0.0002 (0.0001) and 0.0003 (0.0003) between grades II vs. III and III vs. IV, respectively, for MD (MK). In summary, the studies demonstrated great potential towards automating grading gliomas by employing tumour heterogeneity measures on DTI and DKI parameters. (orig.)

  16. Imaging spectroscopy using embedded diffractive optical arrays

    Science.gov (United States)

    Hinnrichs, Michele; Hinnrichs, Bradford

    2017-09-01

    Pacific Advanced Technology (PAT) has developed an infrared hyperspectral camera based on diffractive optic arrays. This approach to hyperspectral imaging has been demonstrated in all three infrared bands SWIR, MWIR and LWIR. The hyperspectral optical system has been integrated into the cold-shield of the sensor enabling the small size and weight of this infrared hyperspectral sensor. This new and innovative approach to an infrared hyperspectral imaging spectrometer uses micro-optics that are made up of an area array of diffractive optical elements where each element is tuned to image a different spectral region on a common focal plane array. The lenslet array is embedded in the cold-shield of the sensor and actuated with a miniature piezo-electric motor. This approach enables rapid infrared spectral imaging with multiple spectral images collected and processed simultaneously each frame of the camera. This paper will present our optical mechanical design approach which results in an infrared hyper-spectral imaging system that is small enough for a payload on a small satellite, mini-UAV, commercial quadcopter or man portable. Also, an application of how this spectral imaging technology can easily be used to quantify the mass and volume flow rates of hydrocarbon gases. The diffractive optical elements used in the lenslet array are blazed gratings where each lenslet is tuned for a different spectral bandpass. The lenslets are configured in an area array placed a few millimeters above the focal plane and embedded in the cold-shield to reduce the background signal normally associated with the optics. The detector array is divided into sub-images covered by each lenslet. We have developed various systems using a different number of lenslets in the area array. Depending on the size of the focal plane and the diameter of the lenslet array will determine the number of simultaneous different spectral images collected each frame of the camera. A 2 x 2 lenslet array will image

  17. Fast Dictionary-Based Reconstruction for Diffusion Spectrum Imaging

    Science.gov (United States)

    Bilgic, Berkin; Chatnuntawech, Itthi; Setsompop, Kawin; Cauley, Stephen F.; Yendiki, Anastasia; Wald, Lawrence L.; Adalsteinsson, Elfar

    2015-01-01

    Diffusion Spectrum Imaging (DSI) reveals detailed local diffusion properties at the expense of substantially long imaging times. It is possible to accelerate acquisition by undersampling in q-space, followed by image reconstruction that exploits prior knowledge on the diffusion probability density functions (pdfs). Previously proposed methods impose this prior in the form of sparsity under wavelet and total variation (TV) transforms, or under adaptive dictionaries that are trained on example datasets to maximize the sparsity of the representation. These compressed sensing (CS) methods require full-brain processing times on the order of hours using Matlab running on a workstation. This work presents two dictionary-based reconstruction techniques that use analytical solutions, and are two orders of magnitude faster than the previously proposed dictionary-based CS approach. The first method generates a dictionary from the training data using Principal Component Analysis (PCA), and performs the reconstruction in the PCA space. The second proposed method applies reconstruction using pseudoinverse with Tikhonov regularization with respect to a dictionary. This dictionary can either be obtained using the K-SVD algorithm, or it can simply be the training dataset of pdfs without any training. All of the proposed methods achieve reconstruction times on the order of seconds per imaging slice, and have reconstruction quality comparable to that of dictionary-based CS algorithm. PMID:23846466

  18. Imaging brain microstructure with diffusion MRI: practicality and applications.

    Science.gov (United States)

    Alexander, Daniel C; Dyrby, Tim B; Nilsson, Markus; Zhang, Hui

    2017-11-29

    This article gives an overview of microstructure imaging of the brain with diffusion MRI and reviews the state of the art. The microstructure-imaging paradigm aims to estimate and map microscopic properties of tissue using a model that links these properties to the voxel scale MR signal. Imaging techniques of this type are just starting to make the transition from the technical research domain to wide application in biomedical studies. We focus here on the practicalities of both implementing such techniques and using them in applications. Specifically, the article summarizes the relevant aspects of brain microanatomy and the range of diffusion-weighted MR measurements that provide sensitivity to them. It then reviews the evolution of mathematical and computational models that relate the diffusion MR signal to brain tissue microstructure, as well as the expanding areas of application. Next we focus on practicalities of designing a working microstructure imaging technique: model selection, experiment design, parameter estimation, validation, and the pipeline of development of this class of technique. The article concludes with some future perspectives on opportunities in this topic and expectations on how the field will evolve in the short-to-medium term. Copyright © 2017 John Wiley & Sons, Ltd.

  19. Fast dictionary-based reconstruction for diffusion spectrum imaging.

    Science.gov (United States)

    Bilgic, Berkin; Chatnuntawech, Itthi; Setsompop, Kawin; Cauley, Stephen F; Yendiki, Anastasia; Wald, Lawrence L; Adalsteinsson, Elfar

    2013-11-01

    Diffusion spectrum imaging reveals detailed local diffusion properties at the expense of substantially long imaging times. It is possible to accelerate acquisition by undersampling in q-space, followed by image reconstruction that exploits prior knowledge on the diffusion probability density functions (pdfs). Previously proposed methods impose this prior in the form of sparsity under wavelet and total variation transforms, or under adaptive dictionaries that are trained on example datasets to maximize the sparsity of the representation. These compressed sensing (CS) methods require full-brain processing times on the order of hours using MATLAB running on a workstation. This work presents two dictionary-based reconstruction techniques that use analytical solutions, and are two orders of magnitude faster than the previously proposed dictionary-based CS approach. The first method generates a dictionary from the training data using principal component analysis (PCA), and performs the reconstruction in the PCA space. The second proposed method applies reconstruction using pseudoinverse with Tikhonov regularization with respect to a dictionary. This dictionary can either be obtained using the K-SVD algorithm, or it can simply be the training dataset of pdfs without any training. All of the proposed methods achieve reconstruction times on the order of seconds per imaging slice, and have reconstruction quality comparable to that of dictionary-based CS algorithm.

  20. Semiautomated spleen volumetry with diffusion-weighted MR imaging.

    Science.gov (United States)

    Lee, Jeongjin; Kim, Kyoung Won; Lee, Ho; Lee, So Jung; Choi, Sanghyun; Jeong, Woo Kyoung; Kye, Heewon; Song, Gi-Won; Hwang, Shin; Lee, Sung-Gyu

    2012-07-01

    In this article, we determined the relative accuracy of semiautomated spleen volumetry with diffusion-weighted (DW) MR images compared to standard manual volumetry with DW-MR or CT images. Semiautomated spleen volumetry using simple thresholding followed by 3D and 2D connected component analysis was performed with DW-MR images. Manual spleen volumetry was performed on DW-MR and CT images. In this study, 35 potential live liver donor candidates were included. Semiautomated volumetry results were highly correlated with manual volumetry results using DW-MR (r = 0.99; P volumetry was significantly shorter compared to that of manual volumetry with DW-MR (P volumetry with DW-MR images can be performed rapidly and accurately when compared with standard manual volumetry. Copyright © 2011 Wiley Periodicals, Inc.

  1. Self-diffusion of polycrystalline ice Ih under confining pressure: Hydrogen isotope analysis using 2-D Raman imaging

    Science.gov (United States)

    Noguchi, Naoki; Kubo, Tomoaki; Durham, William B.; Kagi, Hiroyuki; Shimizu, Ichiko

    2016-08-01

    We have developed a high-resolution technique based on micro Raman spectroscopy to measure hydrogen isotope diffusion profiles in ice Ih. The calibration curve for quantitative analysis of deuterium in ice Ih was constructed using micro Raman spectroscopy. Diffusion experiments using diffusion couples composed of dense polycrystalline H2O and D2O ice were carried out under a gas confining pressure of 100 MPa (to suppress micro-fracturing and pore formation) at temperatures from 235 K to 245 K and diffusion times from 0.2 to 94 hours. Two-dimensional deuterium profiles across the diffusion couples were determined by Raman imaging. The location of small spots of frost from room air could be detected from the shapes of the Raman bands of OH and OD stretching modes, which change because of the effect of the molar ratio of deuterium on the molecular coupling interaction. We emphasize the validity for screening the impurities utilizing the coupling interaction. Some recrystallization and grain boundary migration occurred in recovered diffusion couples, but analysis of two-dimensional diffusion profiles of regions not affected by grain boundary migration allowed us to measure a volume diffusivity for ice at 100 MPa of (2.8 ± 0.4) ×10-3exp[ -57.0 ± 15.4kJ /mol RT ] m2 /s (R is the gas constant, T is temperature). Based on ambient pressure diffusivity measurements by others, this value indicates a high (negative) activation volume for volume diffusivity of -29.5 cm3/mol or more. We can also constrain the value of grain boundary diffusivity in ice at 100 MPa to be volume diffusivity.

  2. Recent Developments in Fluorescence Correlation Spectroscopy for Diffusion Measurements in Planar Lipid Membranes

    Czech Academy of Sciences Publication Activity Database

    Macháň, Radek; Hof, Martin

    2010-01-01

    Roč. 11, č. 2 (2010), s. 427-457 E-ISSN 1422-0067 R&D Projects: GA ČR GA203/08/0114; GA AV ČR GEMEM/09/E006 Institutional research plan: CEZ:AV0Z40400503 Keywords : lateral diffusion * fluorescence fluctuation spectroscopy * confocal microscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.279, year: 2010

  3. The use of photon correlation spectroscopy method for determining diffusion coefficient in brine and herring flesh

    Directory of Open Access Journals (Sweden)

    Shumanova M.V.

    2015-03-01

    Full Text Available The process fish salting has been studied by the method of photon correlation spectroscopy; the distribution of salt concentration in the solution and herring flesh with skin has been found, diffusion coefficients and salt concentrations used for creating a mathematical model of the salting technology have been worked out; the possibility of determination by this method the coefficient of dynamic viscosity of solutions and different media (minced meat etc. has been considered

  4. Diffusion-weighted MR imaging of intracranial tumors

    International Nuclear Information System (INIS)

    Bydder, G.M.; Baudouin, C.J.; Steiner, R.E.; Hajnal, J.V.; Young, I.R.

    1991-01-01

    This paper assesses the effect of anisotropic diffusion weighting on the appearances of cerebral tumors as well as vasogenic and interstitial edema. Diffusion weighting produced a reduction in signal intensity in all or part of the tumors in the majority of cases. However, a relative increase in signal intensity was apparent in four cases. The decrease in signal intensity in vasogenic edema depended on the site and direction of gradient sensitization. Marked increase in conspicuity between tumor and edema was apparent in three cases. Changes in interstitial edema depended in detail in fiber direction. Differentiation between tumor and edema can be improved with diffusion-weighted imaging. Anisotropic change is seen in both vasogenic and interstitial edema

  5. Phase correction of MR perfusion/diffusion images

    International Nuclear Information System (INIS)

    Chenevert, T.L.; Pipe, J.G.; Brunberg, J.A.; Yeung, H.N.

    1989-01-01

    Apparent diffusion coefficient (ADC) and perfusion MR sequences are exceptionally sensitive to minute motion and, therefore, are prone to bulk motions that hamper ADC/perfusion quantification. The authors have developed a phase correction algorithm to substantially reduce this error. The algorithm uses a diffusion-insensitive data set to correct data that are diffusion sensitive but phase corrupt. An assumption of the algorithm is that bulk motion phase shifts are uniform in one dimension, although they may be arbitrarily large and variable from acquisition to acquisition. This is facilitated by orthogonal section selection. The correction is applied after one Fourier transform of a two-dimensional Fourier transform reconstruction. Imaging experiments on rat and human brain demonstrate significant artifact reduction in ADC and perfusion measurements

  6. Magnetic resonance spectroscopy and imaging in cerebral ischemia

    International Nuclear Information System (INIS)

    Rijen, P.C. van.

    1991-01-01

    In-vivo proton and phosphorus magnetic resonance spectroscopy was used to detect changes in cerebral metabolism during ischemia and other types of metabolic stress. Magnetic resonance imaging was performed in an animal model to observe morphological alterations during focal cerebral ischemia. Spectroscopy was performed in animal models with global ischemia, in volunteers during hyperventilation and pharmaco-logically altered cerebral perfusion, and in patients with acute and prolonged focal cerebral ischemia. (author). 396 refs.; 44 figs.; 14 tabs

  7. Harmonization of multi-site diffusion tensor imaging data.

    Science.gov (United States)

    Fortin, Jean-Philippe; Parker, Drew; Tunç, Birkan; Watanabe, Takanori; Elliott, Mark A; Ruparel, Kosha; Roalf, David R; Satterthwaite, Theodore D; Gur, Ruben C; Gur, Raquel E; Schultz, Robert T; Verma, Ragini; Shinohara, Russell T

    2017-11-01

    Diffusion tensor imaging (DTI) is a well-established magnetic resonance imaging (MRI) technique used for studying microstructural changes in the white matter. As with many other imaging modalities, DTI images suffer from technical between-scanner variation that hinders comparisons of images across imaging sites, scanners and over time. Using fractional anisotropy (FA) and mean diffusivity (MD) maps of 205 healthy participants acquired on two different scanners, we show that the DTI measurements are highly site-specific, highlighting the need of correcting for site effects before performing downstream statistical analyses. We first show evidence that combining DTI data from multiple sites, without harmonization, may be counter-productive and negatively impacts the inference. Then, we propose and compare several harmonization approaches for DTI data, and show that ComBat, a popular batch-effect correction tool used in genomics, performs best at modeling and removing the unwanted inter-site variability in FA and MD maps. Using age as a biological phenotype of interest, we show that ComBat both preserves biological variability and removes the unwanted variation introduced by site. Finally, we assess the different harmonization methods in the presence of different levels of confounding between site and age, in addition to test robustness to small sample size studies. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Diffuse reflectance imaging: a tool for guided biopsy

    Science.gov (United States)

    Jayanthi, Jayaraj L.; Subhash, Narayanan; Manju, Stephen; Nisha, Unni G.; Beena, Valappil T.

    2012-01-01

    Accurate diagnosis of premalignant or malignant oral lesions depends on the quality of the biopsy, adequate clinical information and correct interpretation of the biopsy results. The major clinical challenge is to precisely locate the biopsy site in a clinically suspicious lesion. Dips due to oxygenated hemoglobin absorption have been noticed at 545 and 575 nm in the diffusely reflected white light spectra of oral mucosa and the intensity ratio R545/R575 has been found suited for early detection of oral pre-cancers. A multi-spectral diffuse reflectance (DR) imaging system has been developed consisting of an electron multiplying charge coupled device (EMCCD) camera and a liquid crystal tunable filter for guiding the clinician to an optimal biopsy site. Towards this DR images were recorded from 27 patients with potentially malignant lesions on their tongue (dorsal, lateral and ventral sides) and from 44 healthy controls at 545 and 575 nm with the DR imaging system. False colored ratio image R545/R575 of the lesion provides a visual discerning capability that helps in locating the most malignant site for biopsy. Histopathological report of guided biopsy showed that out of the 27 patients 16 were cancers, 9 pre-cancers and 2 lichen planus. In this clinical trial DR imaging has correctly guided 25 biopsy sites, yielding a sensitivity of 93% and a specificity of 98%, thereby establishing the potential of DR imaging as a tool for guided biopsy.

  9. Confined diffusion in tubular structures analyzed by fluorescence correlation spectroscopy on a mirror

    International Nuclear Information System (INIS)

    Etienne, Emilien; Lenne, Pierre-Francois; Sturgis, James N.; Rigneault, Herve

    2006-01-01

    In fluorescence correlation spectroscopy (FCS) analysis it is generally assumed that molecular species diffuse freely in volumes much larger than the three-dimensional FCS observation volume. However, this standard assumption is not valid in many measurement conditions, particularly in tubular structures with diameters in the micrometer range, such as those found in living cells (organelles, dendrites) and microfluidic devices (capillaries,reaction chambers). As a result the measured autocorrelation functions (ACFs) deviate from those predicted for free diffusion, and this can shift the measured diffusion coefficient by as much as ∼50% when the tube diameter is comparable with the axial extension of the FCS observation volume. We show that the range of validity of the FCS measurements can be drastically improved if the tubular structures are located in the close vicinity of a mirror on which FCS is performed. In this case a new fluctuation time in the ACF, arising from the diffusion of fluorescent probes in optical fringes,permits measurement of the real diffusion coefficient within the tubular structure without assumptions about either the confined geometry orthe FCS observation volume geometry. We show that such a measurement can be done when the tubular structure contains at least one pair of dark and bright fringes resulting from interference between the incoming and the reflected excitation beams on the mirror surface. Measurement of the diffusion coefficient of the enhanced green fluorescent protein (EGFP) and IscS-EGFP in the cytoplasm of living Escherichiacoli illustrates the capabilities of the technique

  10. Mechanistic insights of Li+ diffusion within doped LiFePO4 from Muon Spectroscopy.

    Science.gov (United States)

    Johnson, Ian D; Ashton, Thomas E; Blagovidova, Ekaterina; Smales, Glen J; Lübke, Mechthild; Baker, Peter J; Corr, Serena A; Darr, Jawwad A

    2018-03-07

    The Li + ion diffusion characteristics of V- and Nb-doped LiFePO 4 were examined with respect to undoped LiFePO 4 using muon spectroscopy (µSR) as a local probe. As little difference in diffusion coefficient between the pure and doped samples was observed, offering D Li values in the range 1.8-2.3 × 10 -10  cm 2 s -1 , this implied the improvement in electrochemical performance observed within doped LiFePO 4 was not a result of increased local Li + diffusion. This unexpected observation was made possible with the µSR technique, which can measure Li + self-diffusion within LiFePO 4 , and therefore negated the effect of the LiFePO 4 two-phase delithiation mechanism, which has previously prevented accurate Li + diffusion comparison between the doped and undoped materials. Therefore, the authors suggest that µSR is an excellent technique for analysing materials on a local scale to elucidate the effects of dopants on solid-state diffusion behaviour.

  11. Spinal diffusion tensor imaging: a comprehensive review with emphasis on spinal cord anatomy and clinical applications.

    Science.gov (United States)

    Hendrix, Philipp; Griessenauer, Christoph J; Cohen-Adad, Julien; Rajasekaran, Shanmuganathan; Cauley, Keith A; Shoja, Mohammadali M; Pezeshk, Parham; Tubbs, R Shane

    2015-01-01

    Magnetic resonance imaging technology allows for in vivo visualization of fiber tracts of the central nervous system using diffusion-weighted imaging sequences and data processing referred to as "diffusion tensor imaging" and "diffusion tensor tractography." While protocols for high-fidelity diffusion tensor imaging of the brain are well established, the spinal cord has proven a more difficult target for diffusion tensor methods. Here, we review the current literature on spinal diffusion tensor imaging and tractography with special emphasis on neuroanatomical correlations and clinical applications. © 2014 Wiley Periodicals, Inc.

  12. Diffusion tensor imaging in children and adolescents with tuberous sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Karadag, Demet [Institute of Diagnostic and Interventional Radiology, Friedrich Schiller University, Department of Paediatric Radiology, Jena (Germany); Kirikkale Yuksek Ihtisas Hospital, Department of Radiology, Kirirkale (Turkey); Mentzel, Hans-J.; Loebel, Ulrike; Reichenbach, Juergen R.; Kaiser, Werner A. [Institute of Diagnostic and Interventional Radiology, Friedrich Schiller University, Department of Paediatric Radiology, Jena (Germany); Guellmar, Daniel [Institute of Diagnostic and Interventional Radiology, Friedrich Schiller University, Department of Paediatric Radiology, Jena (Germany); Friedrich Schiller University, Biomagnetic Centre, Clinic of Neurology, Jena (Germany); Rating, Tina; Brandl, Ulrich [Friedrich Schiller University, Department of Paediatric Neurology, Jena (Germany)

    2005-10-01

    Tuberous sclerosis (TS) is characterised by benign hamartomatous lesions in many organs. Diffusion tensor imaging (DTI) can detect microstructural changes in pathological processes. To determine apparent diffusion coefficient (ADC) and fractional anisotropy (FA) maps in children with TS and to investigate the diffusion properties in cortical tubers, white-matter lesions, perilesional white matter, and contralateral normal-appearing white matter, and to compare the results with ADC and FA maps of normal age- and sex-matched volunteers. Seven children and adolescents (age range 2-20 years) suffering from TS were included. MRI was performed on a 1.5-T scanner using a transmit/receive coil with T1-W and T2-W spin-echo and FLAIR sequences. DT images were acquired by using a single-shot echo-planar pulse sequence. Diffusion gradients were applied in six different directions with a b value of 1,000 s/mm{sup 2}. ADC was higher in cortical tubers than in the corresponding cortical location of controls. ADC values were higher and FA values were lower in white-matter lesions and perilesional white matter than in both the contralateral normal-appearing white matter of patients and in controls. There were no significant differences for both ADC and FA values in the normal-appearing white matter of patients with TS compared to controls. DTI provides important information about cortical tubers, white-matter abnormalities, and perilesional white matter in patients with TS. (orig.)

  13. Diffusion imaging: technology and clinical application; Diffusionsbildgebung. Technik und klinische Anwendung

    Energy Technology Data Exchange (ETDEWEB)

    Kukuk, Guido Matthias; Greschus, Susanne; Pieper, Claus Christian [Universitaetsklinik Bonn (Germany). Radiologische Klinik; Goldstein, Jan [Staedtisches Klinikum Solingen (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie

    2017-03-15

    While diffusion imaging was predominantly used for cerebral ischemia diagnostics it is now a widely applied MR diagnostic tool for oncologic or inflammatory diseases. The contribution is focused on the fundamentals of diffusion imaging and the most important indications.

  14. Diffusion-weighted imaging features in spinal cord infarction

    International Nuclear Information System (INIS)

    Zhang Jingsong; Huan Yi; Sun Lijun; Chang Yingjuan; Zhao Haitao; Yang Chunmin; Zhang Guangyun

    2005-01-01

    Objective: To analyze the diffusion-weighted MR imaging findings in ischemic spinal cord lesions and discuss the value of diffusion-weighted MR imaging in differentiating diagnosis with inflammatory diseases and tumors. Methods: Six patients (2 male, 4 female) with typical sudden onset of neurological deficits caused by spinal cord ischemia were evaluated. There were no definite etiologies in all patients. DW imaging was performed within 1 to 30 days after the initial neurological symptoms using a Philips Gyroscan 1.5 TMR system. Four patients had other scans including contrast-enhanced MR imaging (CE-MRI) and/or FLAIR scans. Two of them followed up with MR images in three months. All six patients were imaged using a multi-shot, navigator-corrected, echo-planar pulse sequence, and ADC values were calculated in sagittal-oriented plane. Results: MR abnormalities were demonstrated on sagittal T 2 -weighted images with 'patch-like' or 'strip-like' hyperintensities (6/6) and cord enlargement (5/6). Axial T 2 -weighted images showed bilateral (6/6) hyperintensities. In one patient only the posterior spinal artery (PSA) territory was involved. Spinal cord was mainly affected at the cervical (2/6) and thoracolumbar (4/6) region, two of them included the conus medullaris (T10-L1). DW images showed high signals in all infarct lesions, degree of intensity depended on scanning time from ill-onset and progress of illness and whether companied with hemorrhage. In this group, except one case with closely normal ADC value due to one month course of illness, the five others ADC values of lesions calculated from ADC maps arranged from 0.23 x 10 -3 mm 2 /s to 0.47 x 10 -3 mm 2 /s [average value (0.37 ± 0.10) x 10 -3 mm 2 /s], markedly lower than normal parts [ average value (0.89 ± 0.08) x 10 -3 mm 2 /s]. There were marked difference between lesions and normal regions (t=4.71, P 2 W images. Meanwhile, lesions could be displayed much better in DW images than in T 2 W images because

  15. Diffusion-Weighted Magnetic Resonance Imaging in Renal Lesion Characterization

    Directory of Open Access Journals (Sweden)

    Elif Karadeli

    2012-03-01

    Conclusion: The technique has the advantage that it is non-invasive without need for gadolinium administration, takes about 2 minute. This method provides qualitative and quantitative infomation on tissue characterization. DA-MRI and ADC values are important for characterization of renal lesions. Especially, utility of diffusion-weighted magnetic resonance imaging in the patients with risk for nephrogenic systemic fibrosis (NSF could be beneficial. [Cukurova Med J 2012; 37(1: 27-36

  16. Diagnosis of Lumbar Foraminal Stenosis using Diffusion Tensor Imaging

    OpenAIRE

    Eguchi, Yawara; Ohtori, Seiji; Suzuki, Munetaka; Oikawa, Yasuhiro; Yamanaka, Hajime; Tamai, Hiroshi; Kobayashi, Tatsuya; Orita, Sumihisa; Yamauchi, Kazuyo; Suzuki, Miyako; Aoki, Yasuchika; Watanabe, Atsuya; Kanamoto, Hirohito; Takahashi, Kazuhisa

    2016-01-01

    Diagnosis of lumbar foraminal stenosis remains difficult. Here, we report on a case in which bilateral lumbar foraminal stenosis was difficult to diagnose, and in which diffusion tensor imaging (DTI) was useful. The patient was a 52-year-old woman with low back pain and pain in both legs that was dominant on the right. Right lumbosacral nerve compression due to a massive uterine myoma was apparent, but the leg pain continued after a myomectomy was performed. No abnormalities were observed dur...

  17. Image-based spectroscopy for environmental monitoring

    Science.gov (United States)

    Bachmakov, Eduard; Molina, Carolyn; Wynne, Rosalind

    2014-03-01

    An image-processing algorithm for use with a nano-featured spectrometer chemical agent detection configuration is presented. The spectrometer chip acquired from Nano-Optic DevicesTM can reduce the size of the spectrometer down to a coin. The nanospectrometer chip was aligned with a 635nm laser source, objective lenses, and a CCD camera. The images from a nanospectrometer chip were collected and compared to reference spectra. Random background noise contributions were isolated and removed from the diffraction pattern image analysis via a threshold filter. Results are provided for the image-based detection of the diffraction pattern produced by the nanospectrometer. The featured PCF spectrometer has the potential to measure optical absorption spectra in order to detect trace amounts of contaminants. MATLAB tools allow for implementation of intelligent, automatic detection of the relevant sub-patterns in the diffraction patterns and subsequent extraction of the parameters using region-detection algorithms such as the generalized Hough transform, which detects specific shapes within the image. This transform is a method for detecting curves by exploiting the duality between points on a curve and parameters of that curve. By employing this imageprocessing technique, future sensor systems will benefit from new applications such as unsupervised environmental monitoring of air or water quality.

  18. Waveguide volume probe for magnetic resonance imaging and spectroscopy

    DEFF Research Database (Denmark)

    2015-01-01

    The present disclosure relates to a probe for use within the field of nuclear magnetic resonance, such as magnetic resonance imaging (MRI), and magnetic resonance spectroscopy (MRS)). One embodiment relates to an RF probe for magnetic resonance imaging and/or spectroscopy comprising a conductive...... non-magnetic hollow waveguide having an internal volume and at least one open end, one or more capacitors and at least a first conductive non-magnetic wire, wherein said first conductive wire connects at least one of said one or more capacitors to opposite walls of one open end of the waveguide...

  19. Diffusion MR imaging in sporadic Creutzfeldt-Jakob disease

    Directory of Open Access Journals (Sweden)

    Burcak Cakir Pekoz

    2014-08-01

    Full Text Available Creutzfeldt-Jakob disease (CJD is a rare dementing disease and is thought to caused by a prion. It is characterized by rapidly progressive dementia, ataxia, myoclonus, akinetic mutism and eventual death. Brain biopsy or autopsy is required for a definitive diagnosis of CJD. Diffusion-weighted imaging became an important tool for early diagnosis of CJD because of the high sensitivity. We present 59-year-old female patient diagnosed as sporadic CJD with typical MR imagings. [Cukurova Med J 2014; 39(4.000: 880-883

  20. Volume illustration of muscle from diffusion tensor images.

    Science.gov (United States)

    Chen, Wei; Yan, Zhicheng; Zhang, Song; Crow, John Allen; Ebert, David S; McLaughlin, Ronald M; Mullins, Katie B; Cooper, Robert; Ding, Zi'ang; Liao, Jun

    2009-01-01

    Medical illustration has demonstrated its effectiveness to depict salient anatomical features while hiding the irrelevant details. Current solutions are ineffective for visualizing fibrous structures such as muscle, because typical datasets (CT or MRI) do not contain directional details. In this paper, we introduce a new muscle illustration approach that leverages diffusion tensor imaging (DTI) data and example-based texture synthesis techniques. Beginning with a volumetric diffusion tensor image, we reformulate it into a scalar field and an auxiliary guidance vector field to represent the structure and orientation of a muscle bundle. A muscle mask derived from the input diffusion tensor image is used to classify the muscle structure. The guidance vector field is further refined to remove noise and clarify structure. To simulate the internal appearance of the muscle, we propose a new two-dimensional example based solid texture synthesis algorithm that builds a solid texture constrained by the guidance vector field. Illustrating the constructed scalar field and solid texture efficiently highlights the global appearance of the muscle as well as the local shape and structure of the muscle fibers in an illustrative fashion. We have applied the proposed approach to five example datasets (four pig hearts and a pig leg), demonstrating plausible illustration and expressiveness.

  1. Thermal diffusivity imaging with the thermal lens microscope.

    Science.gov (United States)

    Dada, Oluwatosin O; Feist, Peter E; Dovichi, Norman J

    2011-12-01

    A coaxial thermal lens microscope was used to generate images based on both the absorbance and thermal diffusivity of histological samples. A pump beam was modulated at frequencies ranging from 50 kHz to 5 MHz using an acousto-optic modulator. The pump and a CW probe beam were combined with a dichroic mirror, directed into an inverted microscope, and focused onto the specimen. The change in the transmitted probe beam's center intensity was detected with a photodiode. The photodiode's signal and a reference signal from the modulator were sent to a high-speed lock-in amplifier. The in-phase and quadrature signals were recorded as a sample was translated through the focused beams and used to generate images based on the amplitude and phase of the lock-in amplifier's signal. The amplitude is related to the absorbance and the phase is related to the thermal diffusivity of the sample. Thin sections of stained liver and bone tissues were imaged; the contrast and signal-to-noise ratio of the phase image was highest at frequencies from 0.1-1 MHz and dropped at higher frequencies. The spatial resolution was 2.5 μm for both amplitude and phase images, limited by the pump beam spot size. © 2011 Optical Society of America

  2. Spatio-temporal diffusion of dynamic PET images

    International Nuclear Information System (INIS)

    Tauber, C; Chalon, S; Guilloteau, D; Stute, S; Buvat, I; Chau, M; Spiteri, P

    2011-01-01

    Positron emission tomography (PET) images are corrupted by noise. This is especially true in dynamic PET imaging where short frames are required to capture the peak of activity concentration after the radiotracer injection. High noise results in a possible bias in quantification, as the compartmental models used to estimate the kinetic parameters are sensitive to noise. This paper describes a new post-reconstruction filter to increase the signal-to-noise ratio in dynamic PET imaging. It consists in a spatio-temporal robust diffusion of the 4D image based on the time activity curve (TAC) in each voxel. It reduces the noise in homogeneous areas while preserving the distinct kinetics in regions of interest corresponding to different underlying physiological processes. Neither anatomical priors nor the kinetic model are required. We propose an automatic selection of the scale parameter involved in the diffusion process based on a robust statistical analysis of the distances between TACs. The method is evaluated using Monte Carlo simulations of brain activity distributions. We demonstrate the usefulness of the method and its superior performance over two other post-reconstruction spatial and temporal filters. Our simulations suggest that the proposed method can be used to significantly increase the signal-to-noise ratio in dynamic PET imaging.

  3. Edge-Based Image Compression with Homogeneous Diffusion

    Science.gov (United States)

    Mainberger, Markus; Weickert, Joachim

    It is well-known that edges contain semantically important image information. In this paper we present a lossy compression method for cartoon-like images that exploits information at image edges. These edges are extracted with the Marr-Hildreth operator followed by hysteresis thresholding. Their locations are stored in a lossless way using JBIG. Moreover, we encode the grey or colour values at both sides of each edge by applying quantisation, subsampling and PAQ coding. In the decoding step, information outside these encoded data is recovered by solving the Laplace equation, i.e. we inpaint with the steady state of a homogeneous diffusion process. Our experiments show that the suggested method outperforms the widely-used JPEG standard and can even beat the advanced JPEG2000 standard for cartoon-like images.

  4. Image recovery using diffusion equation embedded neural network

    International Nuclear Information System (INIS)

    Torkamani-Azar, F.

    2001-01-01

    Artificial neural networks with their inherent parallelism have been shown to perform well in many processing applications. In this paper, a new self-organizing approach for the recovery of gray level images degraded by additive noise based on embedding the diffusion equation in a neural network (without using a priori knowledge about the image point spread function, noise or original image) is described which enhances and restores gray levels of degraded images and is for application in low-level processing. Two learning features have been proposed which would be effective in the practical implementation of such a network. The recovery procedure needs some parameter estimation such as different error goals. While the required computation is not excessive, the procedure dose not require too many iterations and convergence is very fast. In addition, through the simulation the new network showed that it has superior ability to give a better quality result with a minimum of the sum of the squared error

  5. Diffusion tensor imaging of the brainstem in children with achondroplasia.

    Science.gov (United States)

    Bosemani, Thangamadhan; Orman, Gunes; Carson, Kathryn A; Meoded, Avner; Huisman, Thierry A G M; Poretti, Andrea

    2014-11-01

    The aims of this study were to compare, using diffusion tensor imaging (DTI) of the brainstem, microstructural integrity of the white matter in children with achondroplasia and age-matched participants and to correlate the severity of craniocervical junction (CCJ) narrowing and neurological findings with DTI scalars in children with achondroplasia. This study also aimed to assess the potential role of fibroblast growth factor receptor type 3 on white matter microstructure. Diffusion tensor imaging was performed using a 1.5T magnetic resonance scanner and balanced pairs of diffusion gradients along 20 non-collinear directions. Measurements were obtained from regions of interest, sampled in each pontine corticospinal tract (CST), medial lemniscus, and middle cerebellar peduncle, as well as in the lower brainstem and centrum semiovale, for fractional anisotropy and for mean, axial, and radial diffusivity. In addition, a severity score for achondroplasia was assessed by measuring CCJ narrowing. Eight patients with achondroplasia (seven males, one female; mean age 5y 6mo, range 1y 1mo-15y 1mo) and eight age- and sex-matched comparison participants (mean age 5y 2mo, range 1y 1mo-14y 11mo) were included in this study. Fractional anisotropy was lower and mean diffusivity and radial diffusivity were higher in the lower brainstem of patients with achondroplasia than in age-matched comparison participants. The CST and middle cerebellar peduncle of the participants showed increases in mean, axial, and radial diffusivity. Fractional anisotropy in the lower brainstem was negatively correlated with the degree of CCJ narrowing. No differences in the DTI metrics of the centrum semiovale were observed between the two groups. The reduction in fractional anisotropy and increase in diffusivities in the lower brainstem of participants with achondroplasia may reflect secondary encephalomalacic degeneration and cavitation of the affected white matter tracts as shown by histology. In

  6. Diffusion tensor imaging of the anterior cruciate ligament graft.

    Science.gov (United States)

    Van Dyck, Pieter; Froeling, Martijn; De Smet, Eline; Pullens, Pim; Torfs, Michaël; Verdonk, Peter; Sijbers, Jan; Parizel, Paul M; Jeurissen, Ben

    2017-11-01

    A great need exists for objective biomarkers to assess graft healing following ACL reconstruction to guide the time of return to sports. The purpose of this study was to evaluate the feasibility and reliability of diffusion tensor imaging (DTI) to delineate the anterior cruciate ligament (ACL) graft and to investigate its diffusion properties using a clinical 3T scanner. DTI of the knee (b = 0, 400, and 800 s/mm 2 , 10 diffusion directions, repeated 16 times for a total of 336 diffusion-weighted volumes) was performed at 3T in 17 patients between 3 and 7 months (mean, 4 months) following ACL reconstruction. Tractography was performed by two independent observers to delineate the ACL graft. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were calculated within the graft. Interrater reliability was assessed using the intraclass correlation coefficient (ICC) and the scan-rescan reproducibility was evaluated based on the percentage coefficient of variance (%CV) across 20 repetition bootknife samples. In all subjects, tractography of the ACL graft was feasible. Quantitative evaluation of the diffusion properties of the ACL graft yielded the following mean ± SD values: FA = 0.23 ± 0.04; MD = 1.30 ± 0.11 × 10 -3 mm 2 /s; AD = 1.61 ± 0.12 × 10 -3 mm 2 /s, and RD = 1.15 ± 0.11 × 10 -3 mm 2 /s. Interrater reliability for the DTI parameters was excellent (ICC = 0.91-0.98). Mean %CVs for FA, MD, AD, and RD were 4.6%, 3.5%, 3.7%, and 4.4%, respectively. We demonstrated the feasibility and reliability of DTI for the visualization and quantitative evaluation of the ACL graft at 3T. 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1423-1432. © 2017 International Society for Magnetic Resonance in Medicine.

  7. Homogeneity based segmentation and enhancement of Diffusion Tensor Images : a white matter processing framework

    NARCIS (Netherlands)

    Rodrigues, P.R.

    2011-01-01

    In diffusion magnetic resonance imaging (DMRI) the Brownian motion of the water molecules, within biological tissue, is measured through a series of images. In diffusion tensor imaging (DTI) this diffusion is represented using tensors. DTI describes, in a non-invasive way, the local anisotropy

  8. In vivo characterization of colorectal metastases in human liver using diffuse reflectance spectroscopy: toward guidance in oncological procedures

    Science.gov (United States)

    Spliethoff, Jarich W.; de Boer, Lisanne L.; Meier, Mark A. J.; Prevoo, Warner; de Jong, Jeroen; Kuhlmann, Koert; Bydlon, Torre M.; Sterenborg, Henricus J. C. M.; Hendriks, Benno H. W.; Ruers, Theo J. M.

    2016-09-01

    There is a strong need to develop clinical instruments that can perform rapid tissue assessment at the tip of smart clinical instruments for a variety of oncological applications. This study presents the first in vivo real-time tissue characterization during 24 liver biopsy procedures using diffuse reflectance (DR) spectroscopy at the tip of a core biopsy needle with integrated optical fibers. DR measurements were performed along each needle path, followed by biopsy of the target lesion using the same needle. Interventional imaging was coregistered with the DR spectra. Pathology results were compared with the DR spectroscopy data at the final measurement position. Bile was the primary discriminator between normal liver tissue and tumor tissue. Relative differences in bile content matched with the tissue diagnosis based on histopathological analysis in all 24 clinical cases. Continuous DR measurements during needle insertion in three patients showed that the method can also be applied for biopsy guidance or tumor recognition during surgery. This study provides an important validation step for DR spectroscopy-based tissue characterization in the liver. Given the feasibility of the outlined approach, it is also conceivable to make integrated fiber-optic tools for other clinical procedures that rely on accurate instrument positioning.

  9. Probing GFP-actin diffusion in living cells using fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    Engelke, Hanna; Heinrich, Doris; Rädler, Joachim O.

    2010-01-01

    The cytoskeleton of eukaryotic cells is continuously remodeled by polymerization and depolymerization of actin. Consequently, the relative content of polymerized filamentous actin (F-actin) and monomeric globular actin (G-actin) is subject to temporal and spatial fluctuations. Since fluorescence correlation spectroscopy (FCS) can measure the diffusion of fluorescently labeled actin it seems likely that FCS allows us to determine the dynamics and hence indirectly the structural properties of the cytoskeleton components with high spatial resolution. To this end we investigate the FCS signal of GFP-actin in living Dictyostelium discoideum cells and explore the inherent spatial and temporal signatures of the actin cytoskeleton. Using the free green fluorescent protein (GFP) as a reference, we find that actin diffusion inside cells is dominated by G-actin and slower than diffusion in diluted cell extract. The FCS signal in the dense cortical F-actin network near the cell membrane is probed using the cytoskeleton protein LIM and is found to be slower than cytosolic G-actin diffusion. Furthermore, we show that polymerization of the cytoskeleton induced by Jasplakinolide leads to a substantial decrease of G-actin diffusion. Pronounced fluctuations in the distribution of the FCS correlation curves can be induced by latrunculin, which is known to induce actin waves. Our work suggests that the FCS signal of GFP-actin in combination with scanning or spatial correlation techniques yield valuable information about the local dynamics and concomitant cytoskeletal properties

  10. Renal water molecular diffusion characteristics in healthy native kidneys: assessment with diffusion tensor MR imaging.

    Directory of Open Access Journals (Sweden)

    Zhenfeng Zheng

    Full Text Available BACKGROUND: To explore the characteristics of diffusion tensor imaging (DTI and magnetic resonance (MR imaging in healthy native kidneys. METHODS: Seventy-three patients without chronic kidney disease underwent DTI-MRI with spin echo-echo planar (SE-EPI sequences accompanied by an array spatial sensitivity encoding technique (ASSET. Cortical and medullary mean, axial and radial diffusivity (MD, AD and RD, fractional anisotropy (FA and primary, secondary and tertiary eigenvalues (λ1, λ2, λ3 were analysed in both kidneys and in different genders. RESULTS: Cortical MD, λ2, λ3, and RD values were higher than corresponding medullary values. The cortical FA value was lower than the medullary FA value. Medullary λ1 and RD values in the left kidney were lower than in the right kidney. Medullary λ2, and λ3 values in women were higher than those in men. Medullary FA values in women were lower than those in men. Medullary FA (r = 0.351, P = 0.002 and λ1 (r = 0.277, P = 0.018 positively correlated with eGFR. Medullary FA (r = -0.25, P = 0.033 negatively correlated with age. CONCLUSIONS: Renal water molecular diffusion differences exist in human kidneys and genders. Age and eGFR correlate with medullary FA and primary eigenvalue.

  11. Hemodynamic measurements in rat brain and human muscle using diffuse near-infrared absorption and correlation spectroscopies

    Science.gov (United States)

    Yu, Guoqiang; Durduran, Turgut; Furuya, D.; Lech, G.; Zhou, Chao; Chance, Britten; Greenberg, J. H.; Yodh, Arjun G.

    2003-07-01

    Measurement of concentration, oxygenation, and flow characteristics of blood cells can reveal information about tissue metabolism and functional heterogeneity. An improved multifunctional hybrid system has been built on the basis of our previous hybrid instrument that combines two near-infrared diffuse optical techniques to simultaneously monitor the changes of blood flow, total hemoglobin concentration (THC) and blood oxygen saturation (StO2). Diffuse correlation spectroscopy (DCS) monitors blood flow (BF) by measuring the optical phase shifts caused by moving blood cells, while diffuse photon density wave spectroscopy (DPDW) measures tissue absorption and scattering. Higher spatial resolution, higher data acquisition rate and higher dynamic range of the improved system allow us to monitor rapid hemodynamic changes in rat brain and human muscles. We have designed two probes with different source-detector pairs and different separations for the two types of experiments. A unique non-contact probe mounted on the back of a camera, which allows continuous measurements without altering the blood flow, was employed to in vivo monitor the metabolic responses in rat brain during KCl induced cortical spreading depression (CSD). A contact probe was used to measure changes of blood flow and oxygenation in human muscle during and after cuff occlusion or exercise, where the non-contact probe is not appropriate for monitoring the moving target. The experimental results indicate that our multifunctional hybrid system is capable of in vivo and non-invasive monitoring of the hemodynamic changes in different tissues (smaller tissues in rat brain, larger tissues in human muscle) under different conditions (static versus moving). The time series images of flow during CSD obtained by our technique revealed spatial and temporal hemodynamic changes in rat brain. Two to three fold longer recovery times of flow and oxygenation after cuff occlusion or exercise from calf flexors in a

  12. Nuclear magnetic resonance spectroscopy and imaging

    International Nuclear Information System (INIS)

    Jiang Weiping; Wang Qi; Zhou Xin

    2013-01-01

    This paper briefly introduces the basic principle of nuclear magnetic resonance (NMR). Protein's structures and functions and dynamics studied by liquid NMR are elaborated; methods for enhancing the resolution of solid state NMR and its applications are discussed; the principle of magnetic resonance imaging (MRI) is interpreted, and applications in different aspects are reviewed. Finally, the progress of NMR is commented. (authors)

  13. Diffusion weighted MR imaging of brachial plexus diseases

    International Nuclear Information System (INIS)

    Okinaga, Shuji; Korenaga, Tateo; Tekemura, Atsushi; Tajiri, Yasuhito; Kawano, Ken-Ichi

    2010-01-01

    Diffusion weighted image (DWI) can specifically give running of nerve fibers as they have diffusion anisotropic property and DW whole body imaging with background body signal suppression (DWIBS) procedure, which being capable of imaging cervical and lumber nerve roots, is thus suggested to be useful for diagnosis of diseases related to brachial plexus (BP). The purpose of the present study is to confirm the usefulness of DWIBS by comparison of its images of the normal and sick plexuses. Subjects are 5 normal healthy males (27-36 y), 29 patients (19 M/10 F, 7-73 y) with BP diseases (10 cases of external injury, 6 of obstetric palsy, 2 of paralysis by dysfunctional position, 6 by Schwannoma, 2 by metastasis of breast cancer and 3 by radiation) and, to see the diagnostic specificity, 9 patients (M 7/F 2, 15-64 y) with severely reduced hand force by nervous causes other than BP ones. MRI with Philips Gyroscan INTERA 1.5T machine is conducted for DWIBS by DWI with single shot EPI (echo planar imaging) with the coil of either sensitivity encoding (SENSE) Cardiac, Flex-M or -S. Images are reconstructed 3D by a radiological technician possessing no information concerning patient's conditions, with Philips software Soap-bubble tool on the workstation, and are then evaluated by a radiologist and an orthopedist separately. It is found that BP disorders by injury, obstetric palsy and tumors, of which diagnosis has been difficult hitherto, can be imaged either negatively or positively depending on their history. In radiation paralysis, only 1/3 cases give a reduced signal intensity in the whole BP. DWIBS will be a new diagnostic mean for systemic peripheral nerve diseases as well as BP ones. (T.T.)

  14. NMR clinical imaging and spectroscopy: Its impact on nuclear medicine

    International Nuclear Information System (INIS)

    1990-01-01

    This is a collection of four papers describing aspects of past and future use of nuclear magnetic resonance as a clinical diagnostic tool. The four papers are entitled (1) What Does NMR Offer that Nuclear Medicine Does Not? by Jerry W. Froelich, (2) Oncological Imaging: Now, Future and Impact Jerry W. Froelich, (3) Magnetic Resonance Spectroscopy/Spectroscopic Imaging and Nuclear Medicine: Past, Present and Future by H. Cecil Charles, and (4) MR Cardiology: Now, Future and Impact by Robert J. Herfkens

  15. Application of ultrasound processed images in space: assessing diffuse affectations

    Science.gov (United States)

    Pérez-Poch, A.; Bru, C.; Nicolau, C.

    The purpose of this study was to evaluate diffuse affectations in the liver using texture image processing techniques. Ultrasound diagnose equipments are the election of choice to be used in space environments as they are free from hazardous effects on health. However, due to the need for highly trained radiologists to assess the images, this imaging method is mainly applied on focal lesions rather than on non-focal ones. We have conducted a clinical study on 72 patients with different degrees of chronic hepatopaties and a group of control of 18 individuals. All subjects' clinical reports and results of biopsies were compared to the degree of affectation calculated by our computer system , thus validating the method. Full statistical results are given in the present paper showing a good correlation (r=0.61) between pathologist's report and analysis of the heterogenicity of the processed images from the liver. This computer system to analyze diffuse affectations may be used in-situ or via telemedicine to the ground.

  16. Hydrothermal Processes in the Archean - New Insights from Imaging Spectroscopy

    NARCIS (Netherlands)

    Ruitenbeek, F.J.A. van

    2007-01-01

    The aim of this research was to gain new insights in fossil hydrothermal systems using airborne imaging spectroscopy. Fossil submarine hydrothermal systems in Archean greenstone belts and other geologic terranes are important because of their relationship with volcanic massive sulfide (VMS) mineral

  17. Portable, Fiber-Based, Diffuse Reflection Spectroscopy (DRS) Systems for Estimating Tissue Optical Properties.

    Science.gov (United States)

    Vishwanath, Karthik; Chang, Kevin; Klein, Daniel; Deng, Yu Feng; Chang, Vivide; Phelps, Janelle E; Ramanujam, Nimmi

    2011-02-01

    Steady-state diffuse reflection spectroscopy is a well-studied optical technique that can provide a noninvasive and quantitative method for characterizing the absorption and scattering properties of biological tissues. Here, we compare three fiber-based diffuse reflection spectroscopy systems that were assembled to create a light-weight, portable, and robust optical spectrometer that could be easily translated for repeated and reliable use in mobile settings. The three systems were built using a broadband light source and a compact, commercially available spectrograph. We tested two different light sources and two spectrographs (manufactured by two different vendors). The assembled systems were characterized by their signal-to-noise ratios, the source-intensity drifts, and detector linearity. We quantified the performance of these instruments in extracting optical properties from diffuse reflectance spectra in tissue-mimicking liquid phantoms with well-controlled optical absorption and scattering coefficients. We show that all assembled systems were able to extract the optical absorption and scattering properties with errors less than 10%, while providing greater than ten-fold decrease in footprint and cost (relative to a previously well-characterized and widely used commercial system). Finally, we demonstrate the use of these small systems to measure optical biomarkers in vivo in a small-animal model cancer therapy study. We show that optical measurements from the simple portable system provide estimates of tumor oxygen saturation similar to those detected using the commercial system in murine tumor models of head and neck cancer.

  18. Prediction of tablets disintegration times using near-infrared diffuse reflectance spectroscopy as a nondestructive method.

    Science.gov (United States)

    Donoso, M; Ghaly, Evone S

    2005-01-01

    The goals of this study are to user near-infrared reflectance (NIR) spectroscopy to measure the disintegration time of a series of tablets compacted at different compressional forces, calibrate NIR data vs. laboratory equipment data, develop a model equation, validate the model, and test the model's predictive ability. Seven theophylline tablet formulations of the same composition but with different disintegration time values (0.224, 1.141, 2.797, 5.492, 9.397, 16.8, and 30.092 min) were prepared along with five placebo tablet formulations with different disintegration times. Laboratory disintegration time was compared to near-infrared diffuse reflectance data. Linear regression, quadratic, cubic, and partial least square techniques were used to determine the relationship between disintegration time and near-infrared spectra. The results demonstrated that an increase in disintegration time produced an increase in near-infrared absorbance. Series of model equations, which depended on the mathematical technique used for regression, were developed from the calibration of disintegration time using laboratory equipment vs. the near-infrared diffuse reflectance for each formulation. The results of NIR disintegration time were similar to laboratory tests. The near-infrared diffuse reflectance spectroscopy method is an alternative nondestructive method for measurement of disintegration time of tablets.

  19. Galileo infrared imaging spectroscopy measurements at venus

    Science.gov (United States)

    Carlson, R.W.; Baines, K.H.; Encrenaz, Th.; Taylor, F.W.; Drossart, P.; Kamp, L.W.; Pollack, James B.; Lellouch, E.; Collard, A.D.; Calcutt, S.B.; Grinspoon, D.; Weissman, P.R.; Smythe, W.D.; Ocampo, A.C.; Danielson, G.E.; Fanale, F.P.; Johnson, T.V.; Kieffer, H.H.; Matson, D.L.; McCord, T.B.; Soderblom, L.A.

    1991-01-01

    During the 1990 Galileo Venus flyby, the Near Infrared Mapping Spectrometer investigated the night-side atmosphere of Venus in the spectral range 0.7 to 5.2 micrometers. Multispectral images at high spatial resolution indicate substantial cloud opacity variations in the lower cloud levels, centered at 50 kilometers altitude. Zonal and meridional winds were derived for this level and are consistent with motion of the upper branch of a Hadley cell. Northern and southern hemisphere clouds appear to be markedly different. Spectral profiles were used to derive lower atmosphere abundances of water vapor and other species.

  20. Role of diffusion weighted imaging in musculoskeletal infections: Current perspectives

    International Nuclear Information System (INIS)

    Kumar, Yogesh; Khaleel, Mohammad; Boothe, Ethan; Awdeh, Haitham; Wadhwa, Vibhor; Chhabra, Avneesh

    2017-01-01

    Accurate diagnosis and prompt therapy of musculoskeletal infections are important prognostic factors. In most cases, clinical history, examination and laboratory findings help one make the diagnosis, and routine magnetic resonance imaging (MRI) is useful to identify the extent of the disease process. However, in many situations, a routine MRI may not be specific enough especially if the patient cannot receive contrast intravenously, thereby delaying the appropriate treatment. Diffusion-weighted imaging (DWI) can help in many such situations by providing additional information, accurate characterization and defining the extent of the disease, so that prompt treatment can be initiated. In this article, we illustrate the imaging findings of the spectrum of musculoskeletal infections, emphasizing the role of DWI in this domain. (orig.)

  1. Role of diffusion weighted imaging in musculoskeletal infections: Current perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Yogesh [Yale New Haven Health System at Bridgeport Hospital, Department of Radiology, Bridgeport, CT (United States); Khaleel, Mohammad [UT Southwestern Medical Center, Department of Orthopaedic Surgery, Dallas, TX (United States); Boothe, Ethan; Awdeh, Haitham [UT Southwestern Medical Center, Department of Radiology, Dallas, TX (United States); Wadhwa, Vibhor [University of Arkansas for Medical Sciences, Department of Radiology, Little Rock, AR (United States); Chhabra, Avneesh [UT Southwestern Medical Center, Department of Orthopaedic Surgery, Dallas, TX (United States); UT Southwestern Medical Center, Department of Radiology, Dallas, TX (United States)

    2017-01-15

    Accurate diagnosis and prompt therapy of musculoskeletal infections are important prognostic factors. In most cases, clinical history, examination and laboratory findings help one make the diagnosis, and routine magnetic resonance imaging (MRI) is useful to identify the extent of the disease process. However, in many situations, a routine MRI may not be specific enough especially if the patient cannot receive contrast intravenously, thereby delaying the appropriate treatment. Diffusion-weighted imaging (DWI) can help in many such situations by providing additional information, accurate characterization and defining the extent of the disease, so that prompt treatment can be initiated. In this article, we illustrate the imaging findings of the spectrum of musculoskeletal infections, emphasizing the role of DWI in this domain. (orig.)

  2. Diagnosis of Lumbar Foraminal Stenosis using Diffusion Tensor Imaging.

    Science.gov (United States)

    Eguchi, Yawara; Ohtori, Seiji; Suzuki, Munetaka; Oikawa, Yasuhiro; Yamanaka, Hajime; Tamai, Hiroshi; Kobayashi, Tatsuya; Orita, Sumihisa; Yamauchi, Kazuyo; Suzuki, Miyako; Aoki, Yasuchika; Watanabe, Atsuya; Kanamoto, Hirohito; Takahashi, Kazuhisa

    2016-02-01

    Diagnosis of lumbar foraminal stenosis remains difficult. Here, we report on a case in which bilateral lumbar foraminal stenosis was difficult to diagnose, and in which diffusion tensor imaging (DTI) was useful. The patient was a 52-year-old woman with low back pain and pain in both legs that was dominant on the right. Right lumbosacral nerve compression due to a massive uterine myoma was apparent, but the leg pain continued after a myomectomy was performed. No abnormalities were observed during nerve conduction studies. Computed tomography and magnetic resonance imaging indicated bilateral L5 lumbar foraminal stenosis. DTI imaging was done. The extraforaminal values were decreased and tractography was interrupted in the foraminal region. Bilateral L5 vertebral foraminal stenosis was treated by transforaminal lumbar interbody fusion and the pain in both legs disappeared. The case indicates the value of DTI for diagnosing vertebral foraminal stenosis.

  3. Towards real-time diffuse optical tomography for imaging brain functions cooperated with Kalman estimator

    Science.gov (United States)

    Wang, Bingyuan; Zhang, Yao; Liu, Dongyuan; Ding, Xuemei; Dan, Mai; Pan, Tiantian; Wang, Yihan; Li, Jiao; Zhou, Zhongxing; Zhang, Limin; Zhao, Huijuan; Gao, Feng

    2018-02-01

    Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging method to monitor the cerebral hemodynamic through the optical changes measured at the scalp surface. It has played a more and more important role in psychology and medical imaging communities. Real-time imaging of brain function using NIRS makes it possible to explore some sophisticated human brain functions unexplored before. Kalman estimator has been frequently used in combination with modified Beer-Lamber Law (MBLL) based optical topology (OT), for real-time brain function imaging. However, the spatial resolution of the OT is low, hampering the application of OT in exploring some complicated brain functions. In this paper, we develop a real-time imaging method combining diffuse optical tomography (DOT) and Kalman estimator, much improving the spatial resolution. Instead of only presenting one spatially distributed image indicating the changes of the absorption coefficients at each time point during the recording process, one real-time updated image using the Kalman estimator is provided. Its each voxel represents the amplitude of the hemodynamic response function (HRF) associated with this voxel. We evaluate this method using some simulation experiments, demonstrating that this method can obtain more reliable spatial resolution images. Furthermore, a statistical analysis is also conducted to help to decide whether a voxel in the field of view is activated or not.

  4. Ischemic lesion volume determination on diffusion weighted images vs. apparent diffusion coefficient maps.

    Science.gov (United States)

    Bråtane, Bernt Tore; Bastan, Birgul; Fisher, Marc; Bouley, James; Henninger, Nils

    2009-07-07

    Though diffusion weighted imaging (DWI) is frequently used for identifying the ischemic lesion in focal cerebral ischemia, the understanding of spatiotemporal evolution patterns observed with different analysis methods remains imprecise. DWI and calculated apparent diffusion coefficient (ADC) maps were serially obtained in rat stroke models (MCAO): permanent, 90 min, and 180 min temporary MCAO. Lesion volumes were analyzed in a blinded and randomized manner by 2 investigators using (i) a previously validated ADC threshold, (ii) visual determination of hypointense regions on ADC maps, and (iii) visual determination of hyperintense regions on DWI. Lesion volumes were correlated with 24 hour 2,3,5-triphenyltetrazoliumchloride (TTC)-derived infarct volumes. TTC-derived infarct volumes were not significantly different from the ADC and DWI-derived lesion volumes at the last imaging time points except for significantly smaller DWI lesions in the pMCAO model (p=0.02). Volumetric calculation based on TTC-derived infarct also correlated significantly stronger to volumetric calculation based on last imaging time point derived lesions on ADC maps than DWI (pdetermined lesion volumes on ADC maps and DWI by both investigators correlated significantly with threshold-derived lesion volumes on ADC maps with the former method demonstrating a stronger correlation. There was also a better interrater agreement for ADC map analysis than for DWI analysis. Ischemic lesion determination by ADC was more accurate in final infarct prediction, rater independent, and provided exclusive information on ischemic lesion reversibility.

  5. Artificial neural networks based estimation of optical parameters by diffuse reflectance imaging under in vitro conditions

    Directory of Open Access Journals (Sweden)

    Mahmut Ozan Gökkan

    2017-01-01

    Full Text Available Optical parameters (properties of tissue-mimicking phantoms are determined through noninvasive optical imaging. Objective of this study is to decompose obtained diffuse reflectance into these optical properties such as absorption and scattering coefficients. To do so, transmission spectroscopy is firstly used to measure the coefficients via an experimental setup. Next, the optical properties of each characterized phantom are input for Monte Carlo (MC simulations to get diffuse reflectance. Also, a surface image for each single phantom with its known optical properties is obliquely captured due to reflectance-based geometrical setup using CMOS camera that is positioned at 5∘ angle to the phantoms. For the illumination of light, a laser light source at 633nm wavelength is preferred, because optical properties of different components in a biological tissue on that wavelength are nonoverlapped. During in vitro measurements, we prepared 30 different mixture samples adding clinoleic intravenous lipid emulsion (CILE and evans blue (EB dye into a distilled water. Finally, all obtained diffuse reflectance values are used to estimate the optical coefficients by artificial neural networks (ANNs in inverse modeling. For a biological tissue it is found that the simulated and measured values in our results are in good agreement.

  6. Diffusion kurtosis imaging of the liver at 3 Tesla: in vivo comparison to standard diffusion-weighted imaging.

    Science.gov (United States)

    Budjan, Johannes; Sauter, Elke A; Zoellner, Frank G; Lemke, Andreas; Wambsganss, Jens; Schoenberg, Stefan O; Attenberger, Ulrike I

    2018-01-01

    Background Functional techniques like diffusion-weighted imaging (DWI) are gaining more and more importance in liver magnetic resonance imaging (MRI). Diffusion kurtosis imaging (DKI) is an advanced technique that might help to overcome current limitations of DWI. Purpose To evaluate DKI for the differentiation of hepatic lesions in comparison to conventional DWI at 3 Tesla. Material and Methods Fifty-six consecutive patients were examined using a routine abdominal MR protocol at 3 Tesla which included DWI with b-values of 50, 400, 800, and 1000 s/mm 2 . Apparent diffusion coefficient maps were calculated applying a standard mono-exponential fit, while a non-Gaussian kurtosis fit was used to obtain DKI maps. ADC as well as Kurtosis-corrected diffusion ( D) values were quantified by region of interest analysis and compared between lesions. Results Sixty-eight hepatic lesions (hepatocellular carcinoma [HCC] [n = 25]; hepatic adenoma [n = 4], cysts [n = 18]; hepatic hemangioma [HH] [n = 18]; and focal nodular hyperplasia [n = 3]) were identified. Differentiation of malignant and benign lesions was possible based on both DWI ADC as well as DKI D-values ( P values were in the range of 0.04 to < 0.0001). Conclusion In vivo abdominal DKI calculated using standard b-values is feasible and enables quantitative differentiation between malignant and benign liver lesions. Assessment of conventional ADC values leads to similar results when using b-values below 1000 s/mm 2 for DKI calculation.

  7. Magnetic resonance imaging of epidermoid, including diffusion weighted images and an atypical case

    International Nuclear Information System (INIS)

    Takahashi, Shoki; Higano, Shuichi; Kurihara, Noriko

    1994-01-01

    In order to study the role of magnetic resonance imaging (MRI) in diagnosing intracranial epidermoid, we evaluated the MRI findings on five cases with such tumor, all of which were surgically verified. In addition to standard spin-echo (SE) images obtained in all cases, diffusion-weighted images were acquired in two patients. In four patients, the tumor revealed to be almost isointense relative to cerebrospinal fluid (CSF) on both T 1 -and T 2 -weighted images, while it tended to show slightly hyperintense to CSF on proton-density-weighted images; thus, based on the signal intensity on standard SE images the distinction between epidermoid and arachnoid cyst may be difficult. Furthermore, the presence of the tumor which has a tendency to grow in and along the subarachnoid space causing relatively minimal mass effect may be overlooked. Diffusion-weighted images were shown to have advantages in such cases by demonstrating the tumor unequivocally as a mass of high signal, and differentiating it from arachnoid cysts. In the remaining patient, its appearance was atypical, showing bright signal on both T 1 -and T 2 -weighted images. In conclusion free of bone artifacts, multiplanar MRI with additional diffusion-weighted images provides a clear demonstration of epidermoid, and its differentiation from arachnoid cyst, thus obviating the need for CT cisternography. (author)

  8. Planning JWST NIRSpec MSA spectroscopy using NIRCam pre-images

    Science.gov (United States)

    Beck, Tracy L.; Ubeda, Leonardo; Kassin, Susan A.; Gilbert, Karoline; Karakla, Diane M.; Reid, I. N.; Blair, William P.; Keyes, Charles D.; Soderblom, D. R.; Peña-Guerrero, Maria A.

    2016-07-01

    The Near-Infrared Spectrograph (NIRSpec) is the work-horse spectrograph at 1-5microns for the James Webb Space Telescope (JWST). A showcase observing mode of NIRSpec is the multi-object spectroscopy with the Micro-Shutter Arrays (MSAs), which consist of a quarter million tiny configurable shutters that are 0. ''20×0. ''46 in size. The NIRSpec MSA shutters can be opened in adjacent rows to create flexible and positionable spectroscopy slits on prime science targets of interest. Because of the very small shutter width, the NIRSpec MSA spectral data quality will benefit significantly from accurate astrometric knowledge of the positions of planned science sources. Images acquired with the Hubble Space Telescope (HST) have the optimal relative astrometric accuracy for planning NIRSpec observations of 5-10 milli-arcseconds (mas). However, some science fields of interest might have no HST images, galactic fields can have moderate proper motions at the 5mas level or greater, and extragalactic images with HST may have inadequate source information at NIRSpec wavelengths beyond 2 microns. Thus, optimal NIRSpec spectroscopy planning may require pre-imaging observations with the Near-Infrared Camera (NIRCam) on JWST to accurately establish source positions for alignment with the NIRSpec MSAs. We describe operational philosophies and programmatic considerations for acquiring JWST NIRCam pre-image observations for NIRSpec MSA spectroscopic planning within the same JWST observing Cycle.

  9. Differences in Gaussian diffusion tensor imaging and non-Gaussian diffusion kurtosis imaging model-based estimates of diffusion tensor invariants in the human brain.

    Science.gov (United States)

    Lanzafame, S; Giannelli, M; Garaci, F; Floris, R; Duggento, A; Guerrisi, M; Toschi, N

    2016-05-01

    An increasing number of studies have aimed to compare diffusion tensor imaging (DTI)-related parameters [e.g., mean diffusivity (MD), fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD)] to complementary new indexes [e.g., mean kurtosis (MK)/radial kurtosis (RK)/axial kurtosis (AK)] derived through diffusion kurtosis imaging (DKI) in terms of their discriminative potential about tissue disease-related microstructural alterations. Given that the DTI and DKI models provide conceptually and quantitatively different estimates of the diffusion tensor, which can also depend on fitting routine, the aim of this study was to investigate model- and algorithm-dependent differences in MD/FA/RD/AD and anisotropy mode (MO) estimates in diffusion-weighted imaging of human brain white matter. The authors employed (a) data collected from 33 healthy subjects (20-59 yr, F: 15, M: 18) within the Human Connectome Project (HCP) on a customized 3 T scanner, and (b) data from 34 healthy subjects (26-61 yr, F: 5, M: 29) acquired on a clinical 3 T scanner. The DTI model was fitted to b-value =0 and b-value =1000 s/mm(2) data while the DKI model was fitted to data comprising b-value =0, 1000 and 3000/2500 s/mm(2) [for dataset (a)/(b), respectively] through nonlinear and weighted linear least squares algorithms. In addition to MK/RK/AK maps, MD/FA/MO/RD/AD maps were estimated from both models and both algorithms. Using tract-based spatial statistics, the authors tested the null hypothesis of zero difference between the two MD/FA/MO/RD/AD estimates in brain white matter for both datasets and both algorithms. DKI-derived MD/FA/RD/AD and MO estimates were significantly higher and lower, respectively, than corresponding DTI-derived estimates. All voxelwise differences extended over most of the white matter skeleton. Fractional differences between the two estimates [(DKI - DTI)/DTI] of most invariants were seen to vary with the invariant value itself as well as with MK

  10. Dynamics of normal and superfluid fogs using diffusing-wave spectroscopy

    International Nuclear Information System (INIS)

    Kim, Heetae; Lemieux, Pierre-Anthony; Durian, Douglas J.; Williams, Gary A.

    2004-01-01

    The dynamics of normal and superfluid fogs are studied using the technique of diffusing-wave spectroscopy. For a water fog generated with a 1.75 MHz piezoelectric driver below the liquid surface, the 7 μm diameter droplets are found to have diffusive dynamics for correlation times long compared to the viscous time. For a fog of 10 μm diameter superfluid helium droplets in helium vapor at 1.5 K the motion appears to be ballistic for correlation times short compared to the viscous time. The velocity correlations between the helium droplets are found to depend on the initial velocity with which the droplets are injected from the helium surface into the fog

  11. Fluorescence Correlation Spectroscopy to Study Diffusion of Polymer Chains within Layered Hydrogen-Bonded Polymer Films

    Science.gov (United States)

    Pristinski, Denis; Kharlampieva, Evguenia; Sukhishvili, Svetlana

    2002-03-01

    Fluorescence Correlation Spectroscopy (FCS) has been used to probe molecular motions within polymer multilayers formed by hydrogen-bonding sequential self-assembly. Polyethylene glycol (PEG) molecules were end-labeled with the fluorescent tags, and self-assembled with polymethacrylic acid (PMAA) using layer-by-layer deposition. We have found that molecules included in the top adsorbed layer have significant mobility at the millisecond time scale, probably due to translational diffusion. However, their dynamics deviate from classical Brownian motion with a single diffusion time. Possible reasons for the deviation are discussed. We found that motions were significantly slowed with increasing depth within the PEG/PMAA multilayer. This phenomena occured in a narrow pH range around 4.0 in which intermolecular interactions were relatively weak.

  12. Diffusion-weighted imaging in patients with progressive multifocal leukoencephalopathy

    Energy Technology Data Exchange (ETDEWEB)

    Cosottini, M. [University of Pisa, Department of Neuroscience, Pisa (Italy); Service of Neuroradiology AO, Pisa (Italy); Tavarelli, C.; De Cori, S.; Bartolozzi, C. [University of Pisa, Department of Radiology, Pisa (Italy); Del Bono, L.; Doria, G. [Unit of Infectious Diseases AO, Pisa (Italy); Giannelli, M. [Unit of Medical Physics, Pisa (Italy); Michelassi, M.C. [Service of Neuroradiology AO, Pisa (Italy); Murri, L. [University of Pisa, Department of Neuroscience, Pisa (Italy)

    2008-05-15

    Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease of the central nervous system due to JC polyoma virus infection of oligodendrocytes. PML develops in patients with impaired T-cell function as occurs in HIV, malignancy or immunosuppressive drugs users. Until now no imaging methods have been reported to correlate with clinical status. Diffusion-weighted imaging (DWI) is a robust MRI tool in investigating white matter architecture and diseases. The aim of our work was to assess diffusion abnormalities in focal white matter lesions in patients with PML and to correlate the lesion load measured with conventional MRI and DWI to clinical variables. We evaluated eight patients with a biopsy or laboratory-supported diagnosis of PML. All patients underwent MRI including conventional sequences (fluid attenuated inversion recovery-FLAIR) and DWI. Mean diffusivity (MD) maps were used to quantify diffusion on white matter lesions. Global lesion load was calculated by manually tracing lesions on FLAIR images, while total, central core and peripheral lesion loads were calculated by manually tracing lesions on DWI images. Lesion load obtained with the conventional or DWI-based methods were correlated with clinical variables such as disease duration, disease severity and survival. White matter focal lesions are characterized by a central core with low signal on DWI images and high MD (1.853 x 10{sup -3} mm2/s), surrounded by a rim of high signal intensity on DWI and lower MD (1.1 x 10{sup -3} mm2/s). The MD value of normal-appearing white matter is higher although not statistically significant (0.783 x 10{sup -3} mm2/s) with respect to control subjects (0.750 x 10{sup -3} mm2/s). Inter-rater correlations of global lesion load between FLAIR (3.96%) and DWI (3.43%) was excellent (ICC =0.87). Global lesion load on FLAIR and DWI correlates with disease duration and severity (respectively, p = 0.037, p = 0.0272 with Karnofsky scale and p = 0.0338 with

  13. In vivo time-gated diffuse correlation spectroscopy at quasi-null source-detector separation.

    Science.gov (United States)

    Pagliazzi, M; Sekar, S Konugolu Venkata; Di Sieno, L; Colombo, L; Durduran, T; Contini, D; Torricelli, A; Pifferi, A; Mora, A Dalla

    2018-06-01

    We demonstrate time domain diffuse correlation spectroscopy at quasi-null source-detector separation by using a fast time-gated single-photon avalanche diode without the need of time-tagging electronics. This approach allows for increased photon collection, simplified real-time instrumentation, and reduced probe dimensions. Depth discriminating, quasi-null distance measurement of blood flow in a human subject is presented. We envision the miniaturization and integration of matrices of optical sensors of increased spatial resolution and the enhancement of the contrast of local blood flow changes.

  14. Antibiogramj: A tool for analysing images from disk diffusion tests.

    Science.gov (United States)

    Alonso, C A; Domínguez, C; Heras, J; Mata, E; Pascual, V; Torres, C; Zarazaga, M

    2017-05-01

    Disk diffusion testing, known as antibiogram, is widely applied in microbiology to determine the antimicrobial susceptibility of microorganisms. The measurement of the diameter of the zone of growth inhibition of microorganisms around the antimicrobial disks in the antibiogram is frequently performed manually by specialists using a ruler. This is a time-consuming and error-prone task that might be simplified using automated or semi-automated inhibition zone readers. However, most readers are usually expensive instruments with embedded software that require significant changes in laboratory design and workflow. Based on the workflow employed by specialists to determine the antimicrobial susceptibility of microorganisms, we have designed a software tool that, from images of disk diffusion tests, semi-automatises the process. Standard computer vision techniques are employed to achieve such an automatisation. We present AntibiogramJ, a user-friendly and open-source software tool to semi-automatically determine, measure and categorise inhibition zones of images from disk diffusion tests. AntibiogramJ is implemented in Java and deals with images captured with any device that incorporates a camera, including digital cameras and mobile phones. The fully automatic procedure of AntibiogramJ for measuring inhibition zones achieves an overall agreement of 87% with an expert microbiologist; moreover, AntibiogramJ includes features to easily detect when the automatic reading is not correct and fix it manually to obtain the correct result. AntibiogramJ is a user-friendly, platform-independent, open-source, and free tool that, up to the best of our knowledge, is the most complete software tool for antibiogram analysis without requiring any investment in new equipment or changes in the laboratory. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Diffusion-weighted MR imaging of thyroid nodules

    International Nuclear Information System (INIS)

    Bozgeyik, Zulkif; Coskun, Sonay; Ogur, Erkin; Dagli, A.F.; Ozkan, Yusuf; Sahpaz, Fatih

    2009-01-01

    The purpose of our study was to determine the diagnostic role of diffusion-weighted imaging (DWI) in the differentiating of malignant and benign thyroid nodules by using fine needle aspiration biopsy cytology criteria as a reference standard. The apparent diffusion coefficient (ADC) values of the normal-looking thyroid parenchyma were also evaluated both in normal patients and in patients with nodules. Between March 2007 and February 2008, 76 consecutive patients with ultrasound-diagnosed thyroid nodules and 20 healthy subjects underwent diffusion-weighted MR imaging by using single-shot spin echo, echo planar imaging. A total of 93 nodules were included in the study using the following b factors 100, 200, and 300 mm 2 /s. ADC values of thyroid nodules and normal area in all subjects were calculated and compared using suitable statistical analysis. Mean ADC values for malignant and benign nodules were 0.96±0.65 x 10 -3 and 3.06±0.71 x 10 -3 mm 2 /s. for b-300 factor, 0.56±0.43 x 10 -3 and 1.80±0.60 x 10 -3 mm 2 /s for b-200, and 0.30±0.20 x 10 -3 and 1.15±0.43 x 10 -3 mm 2 /s, for b-300, respectively. Mean ADC values of malignant nodules were lower than benign nodules. There were significant differences in ADC values between benign and malignant nodules. ADC values among normal-appearing thyroid parenchyma of patients and normal-appearing thyroid parenchyma of healthy subjects were insignificant at all b factors. Benign nodules have higher ADC values than malignant ones. DWI may be helpful in differentiating malign and benign thyroid nodules. (orig.)

  16. Diffusion tensor imaging for target volume definition in glioblastoma multiforme

    Energy Technology Data Exchange (ETDEWEB)

    Berberat, Jatta; Remonda, Luca [Cantonal Hospital, Department of Neuro-radiology, Aarau (Switzerland); McNamara, Jane; Rogers, Susanne [Cantonal Hospital, Department of Radiation Oncology, Aarau (Switzerland); Bodis, Stephan [Cantonal Hospital, Department of Radiation Oncology, Aarau (Switzerland); University Hospital, Department of Radiation Oncology, Zurich (Switzerland)

    2014-10-15

    Diffusion tensor imaging (DTI) is an MR-based technique that may better detect the peritumoural region than MRI. Our aim was to explore the feasibility of using DTI for target volume delineation in glioblastoma patients. MR tensor tracts and maps of the isotropic (p) and anisotropic (q) components of water diffusion were coregistered with CT in 13 glioblastoma patients. An in-house image processing program was used to analyse water diffusion in each voxel of interest in the region of the tumour. Tumour infiltration was mapped according to validated criteria and contralateral normal brain was used as an internal control. A clinical target volume (CTV) was generated based on the T{sub 1}-weighted image obtained using contrast agent (T{sub 1Gd}), tractography and the infiltration map. This was compared to a conventional T{sub 2}-weighted CTV (T{sub 2}-w CTV). Definition of a diffusion-based CTV that included the adjacent white matter tracts proved highly feasible. A statistically significant difference was detected between the DTI-CTV and T{sub 2}-w CTV volumes (p < 0.005, t = 3.480). As the DTI-CTVs were smaller than the T{sub 2}-w CTVs (tumour plus peritumoural oedema), the pq maps were not simply detecting oedema. Compared to the clinical planning target volume (PTV), the DTI-PTV showed a trend towards volume reduction. These diffusion-based volumes were smaller than conventional volumes, yet still included sites of tumour recurrence. Extending the CTV along the abnormal tensor tracts in order to preserve coverage of the likely routes of dissemination, whilst sparing uninvolved brain, is a rational approach to individualising radiotherapy planning for glioblastoma patients. (orig.) [German] Die Diffusions-Tensor-Bildgebung (DTI) ist eine MR-Technik, die dank der Erfassung des peritumoralen Bereichs eine Verbesserung bezueglich MRI bringt. Unser Ziel war die Pruefung der Machbarkeit der Verwendung der DTI fuer die Zielvolumenabgrenzung fuer Patienten mit

  17. Imaging Appearance of Human Immunodeficiency Virus Encephalitis on the Diffusion Weighted Images: A Case Report

    International Nuclear Information System (INIS)

    Lim, Hun Cheol; Yu, In Kyu; Oh, Keon Se

    2011-01-01

    Imaging finding of human immunodeficiency virus (HIV) encephalitis contain bilateral, symmetric, patchy, or diffuse increased T2WI signal intensities in the basal ganglia, cerebellum, brainstem, and centrum semiovale. In particular, the centrum semiovale is most commonly involved. Most of the HIV encephalitis cases are accompanied by brain atrophy. No previous study has reported symmetric increased signal intensity at the bilateral centrum semiovale without brain atrophy on diffusion weighted images in HIV encephalitis patients. Here, we report a case of this. We suggest that radiologists should consider the possibility of HIV encephalitis if there are symmetric increases in signal intensity at the bilateral centrum semiovale on diffusion weighted images of patients with a history of HIV infection.

  18. Diffusion tensor imaging of the normal prostate at 3 Tesla

    International Nuclear Information System (INIS)

    Guerses, Bengi; Kabakci, Neslihan; Kovanlikaya, Arzu; Firat, Zeynep; Bayram, Ali; Kovanlikaya, Ilhami; Ulud, Aziz M.

    2008-01-01

    The aim of this study was to assess the feasibility of diffusion tensor imaging (DTI) of the prostate and to determine normative fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of healthy prostate with a 3-Tesla magnetic resonance imaging (MRI) system. Thirty volunteers with a mean age of 28 (25-35) years were scanned with a 3-Tesla MRI (Intera Achieva; Philips, The Netherlands) system using a six-channel phased array coil. Initially, T2-weighted turbo spin-echo (TSE) axial images of the prostate were obtained. In two subjects, a millimetric hypointense signal change was detected in the peripheral zones on T2-weighted TSE images. These two subjects were excluded from the study. DTI with single-shot echo-planar imaging (ssEPI) was performed in the remaining 28 subjects. ADC and FA values were measured using the manufacturer supplied software by positioning 9-pixel ROIs on each zone. Differences between parameters of the central and peripheral zones were assessed. Mean ADC value of the central (1.220 ± 0.271 x 10 -3 mm 2 /s) was found to be significantly lower when compared with the peripheral gland (1.610 ± 0.347 x 10 -3 mm 2 /s) (P < 0.01). Mean FA of the central gland was significantly higher (0.26), compared with the peripheral gland (0.16) (P < 0.01). This study shows the feasibility of prostate DTI with a 3-Tesla MR system and the normative FA and ADC values of peripheral and central zones of the normal prostate. The results are compatible with the microstructural organization of the gland. (orig.)

  19. Diffusion tensor imaging using multiple coils for mouse brain connectomics.

    Science.gov (United States)

    Nouls, John C; Badea, Alexandra; Anderson, Robert B J; Cofer, Gary P; Allan Johnson, G

    2018-04-19

    The correlation between brain connectivity and psychiatric or neurological diseases has intensified efforts to develop brain connectivity mapping techniques on mouse models of human disease. The neural architecture of mouse brain specimens can be shown non-destructively and three-dimensionally by diffusion tensor imaging, which enables tractography, the establishment of a connectivity matrix and connectomics. However, experiments on cohorts of animals can be prohibitively long. To improve throughput in a 7-T preclinical scanner, we present a novel two-coil system in which each coil is shielded, placed off-isocenter along the axis of the magnet and connected to a receiver circuit of the scanner. Preservation of the quality factor of each coil is essential to signal-to-noise ratio (SNR) performance and throughput, because mouse brain specimen imaging at 7 T takes place in the coil-dominated noise regime. In that regime, we show a shielding configuration causing no SNR degradation in the two-coil system. To acquire data from several coils simultaneously, the coils are placed in the magnet bore, around the isocenter, in which gradient field distortions can bias diffusion tensor imaging metrics, affect tractography and contaminate measurements of the connectivity matrix. We quantified the experimental alterations in fractional anisotropy and eigenvector direction occurring in each coil. We showed that, when the coils were placed 12 mm away from the isocenter, measurements of the brain connectivity matrix appeared to be minimally altered by gradient field distortions. Simultaneous measurements on two mouse brain specimens demonstrated a full doubling of the diffusion tensor imaging throughput in practice. Each coil produced images devoid of shading or artifact. To further improve the throughput of mouse brain connectomics, we suggested a future expansion of the system to four coils. To better understand acceptable trade-offs between imaging throughput and connectivity

  20. [Dementias: diagnostic contribution of imaging and proton magnetic resonance spectroscopy].

    Science.gov (United States)

    Arana, E; Martínez-Granados, B; Marti-Bonmati, L; Martínez-Bisbal, M C; Gil, A; Blasco, C; Celda, B

    2007-06-01

    The objective is analyze the complementarity between 1H magnetic resonance spectroscopy (MRS) and magnetic resonance (MR) imaging in the global diagnosis of Alzheimer's disease (AD) or vascular dementia (VD). We studied 168 patients with cognitive impairment from AD, VD, mild cognitive impairment (MCI) and major depression. All patients were evaluated by brain MR imaging and MRS using two sample volumes localized at right medial temporal gyrus and posterior parietal gyrus. Metabolites analyzed were N-acetylaspartate (NAA), myo-Inositol (mI), Choline (Cho) and creatine (Cr), as standard references for obtaining the Co/Cr, mI/Cr and NAA/Cr ratios. Imaging and spectroscopy alterations were graded from 0 to 4 and the average of both was used to draw ROC and SROC curves. Area under ROC curve (Az) was used as a measure of discriminative ability. Combination of MR imaging and MRS significantly improved AD diagnosis (Global Az: 0.722 vs. MR imaging Az: 0.624; p: 0.003). However, the combination of MR imaging and MRS did not improve VD diagnosis. SROC curve obtained for the diagnosis of global dementia was Az: 0.6658 with 0.67 sensitivity and 0.65 specificity. Combination of both MR techniques significantly improved AD diagnosis versus MR imaging alone. More studies are needed to enhance VD classification. Metabolic data found by MRS can be useful to differentiate cognitive impairment

  1. Diffuse optical imaging using spatially and temporally modulated light

    Science.gov (United States)

    O'Sullivan, Thomas D.; Cerussi, Albert E.; Cuccia, David J.; Tromberg, Bruce J.

    2012-07-01

    The authors describe the development of diffuse optical imaging (DOI) technologies, specifically the use of spatial and temporal modulation to control near infrared light propagation in thick tissues. We present theory and methods of DOI focusing on model-based techniques for quantitative, in vivo measurements of endogenous tissue absorption and scattering properties. We specifically emphasize the common conceptual framework of the scalar photon density wave for both temporal and spatial frequency-domain approaches. After presenting the history, theoretical foundation, and instrumentation related to these methods, we provide a brief review of clinical and preclinical applications from our research as well as our outlook on the future of DOI technology.

  2. Diffusion-weighted and diffusion tensor imaging for pediatric musculoskeletal disorders

    International Nuclear Information System (INIS)

    MacKenzie, John D.; Gonzalez, Leonardo; Hernandez, Andrea; Ruppert, Kai; Jaramillo, Diego

    2007-01-01

    Diffusion-weighted imaging (DWI) is a powerful tool that has recently been applied to evaluate several pediatric musculoskeletal disorders. DWI probes abnormalities of tissue structure by detecting microscopic changes in water mobility that develop when disease alters the organization of normal tissue. DWI provides tissue characterization at a cellular level beyond what is available with other imaging techniques, and can sometimes identify pathology before gross anatomic alterations manifest. These features of early detection and tissue characterization make DWI particularly appealing for probing diseases that affect the musculoskeletal system. This article focuses on the current and future applications of DWI in the musculoskeletal system, with particular attention paid to pediatric disorders. Although most of the applications are experimental, we have emphasized the current state of knowledge and the main research questions that need to be investigated. (orig.)

  3. Optimal Parameters to Determine the Apparent Diffusion Coefficient in Diffusion Weighted Imaging via Simulation

    Science.gov (United States)

    Perera, Dimuthu

    Diffusion weighted (DW) Imaging is a non-invasive MR technique that provides information about the tissue microstructure using the diffusion of water molecules. The diffusion is generally characterized by the apparent diffusion coefficient (ADC) parametric map. The purpose of this study is to investigate in silico how the calculation of ADC is affected by image SNR, b-values, and the true tissue ADC. Also, to provide optimal parameter combination depending on the percentage accuracy and precision for prostate peripheral region cancer application. Moreover, to suggest parameter choices for any type of tissue, while providing the expected accuracy and precision. In this research DW images were generated assuming a mono-exponential signal model at two different b-values and for known true ADC values. Rician noise of different levels was added to the DWI images to adjust the image SNR. Using the two DWI images, ADC was calculated using a mono-exponential model for each set of b-values, SNR, and true ADC. 40,000 ADC data were collected for each parameter setting to determine the mean and the standard-deviation of the calculated ADC, as well as the percentage accuracy and precision with respect to the true ADC. The accuracy was calculated using the difference between known and calculated ADC. The precision was calculated using the standard-deviation of calculated ADC. The optimal parameters for a specific study was determined when both the percentage accuracy and precision were minimized. In our study, we simulated two true ADCs (ADC 0.00102 for tumor and 0.00180 mm2/s for normal prostate peripheral region tissue). Image SNR was varied from 2 to 100 and b-values were varied from 0 to 2000s/mm2. The results show that the percentage accuracy and percentage precision were minimized with image SNR. To increase SNR, 10 signal-averagings (NEX) were used considering the limitation in total scan time. The optimal NEX combination for tumor and normal tissue for prostate

  4. Value of magnetic resonance imaging in diffuse liver diseases; Stellenwert der MRT bei diffusen Lebererkrankungen

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, N.; D' Anastasi, M.; Reiser, M.F.; Zech, C.J. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Campus Grosshadern, Institut fuer Klinische Radiologie, Muenchen (Germany)

    2012-08-15

    Diffuse liver diseases show an increasing prevalence. The diagnostic gold standard of liver biopsy has several disadvantages. There is a clinical demand for non-invasive imaging-based techniques to qualitatively and quantitatively evaluate the entire liver. Ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI) are routinely used. Steatosis: chemical shift and frequency selective imaging, MR spectroscopy (MRS). Hemochromatosis: MR-based iron quantification. Fibrosis: MR elastography, diffusion, intravoxel incoherent motion (IVIM) and MR perfusion. T1-weighted in and opposed phase imaging is the clinically most frequently used MR technique to noninvasively detect and quantify steatosis. New methods for quantification that are not influenced by confounders like iron overload are under investigation. The most sensitive method to measure the fat content of the liver is MRS. As data acquisition and analysis remain complex and there is no whole organ coverage, MRS of the liver is not a routine method. With an optimized protocol incorporating T2* sequences, MRI is the modality of choice to quantify iron overload in hemochromatosis. Standard MR sequences cannot depict early stages of liver fibrosis. Advanced MR techniques (e.g. elastography, diffusion, IVIM and perfusion) for noninvasive assessment of liver fibrosis appear promising but their role has to be further investigated. (orig.) [German] Die Praevalenz diffuser Lebererkrankungen nimmt zu. Der klinische Goldstandard, die Leberbiopsie, hat zahlreiche Nachteile. Es besteht ein Bedarf an bildgebenden Verfahren zur nichtinvasiven qualitativen und quantitativen Beurteilung der gesamten Leber bei diesen Erkrankungen. Hier sind Ultraschall, CT und MRT zu nennen. Steatosis: Chemical-shift- und frequenzselektive Bildgebung, MR-Spektroskopie (MRS) zur Fettquantifizierung. Haemochromatose: MR-basierte Eisenquantifizierung. Fibrose: MR-Elastographie, Diffusion, ''intravoxel incoherent motion

  5. An introduction to visualization of diffusion tensor imaging and its applications

    NARCIS (Netherlands)

    Vilanova, A.; Zhang, S.; Kindlmann, G.; Laidlaw, D.H.; Weickert, J.; Hagen, H.

    2005-01-01

    Summary. Water diffusion is anisotropic in organized tissues such as white matter and muscle. Diffusion tensor imaging (DTI), a non-invasive MR technique, measures water self-diffusion rates and thus gives an indication of the underlying tissue microstructure. The diffusion rate is often expressed

  6. Intravoxel water diffusion heterogeneity MR imaging of nasopharyngeal carcinoma using stretched exponential diffusion model

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Vincent; Khong, Pek Lan [University of Hong Kong, Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, Queen Mary Hospital, Pok Fu Lam (China); Lee, Victor Ho Fun; Lam, Ka On; Sze, Henry Chun Kin [University of Hong Kong, Department of Clinical Oncology, Li Ka Shing Faculty of Medicine, Queen Mary Hospital, Pok Fu Lam (China); Chan, Queenie [Philips Healthcare, Hong Kong, Shatin, New Territories (China)

    2015-06-01

    To determine the utility of stretched exponential diffusion model in characterisation of the water diffusion heterogeneity in different tumour stages of nasopharyngeal carcinoma (NPC). Fifty patients with newly diagnosed NPC were prospectively recruited. Diffusion-weighted MR imaging was performed using five b values (0-2,500 s/mm{sup 2}). Respective stretched exponential parameters (DDC, distributed diffusion coefficient; and alpha (α), water heterogeneity) were calculated. Patients were stratified into low and high tumour stage groups based on the American Joint Committee on Cancer (AJCC) staging for determination of the predictive powers of DDC and α using t test and ROC curve analyses. The mean ± standard deviation values were DDC = 0.692 ± 0.199 (x 10{sup -3} mm{sup 2}/s) for low stage group vs 0.794 ± 0.253 (x 10{sup -3} mm{sup 2}/s) for high stage group; α = 0.792 ± 0.145 for low stage group vs 0.698 ± 0.155 for high stage group. α was significantly lower in the high stage group while DDC was negatively correlated. DDC and α were both reliable independent predictors (p < 0.001), with α being more powerful. Optimal cut-off values were (sensitivity, specificity, positive likelihood ratio, negative likelihood ratio) DDC = 0.692 x 10{sup -3} mm{sup 2}/s (94.4 %, 64.3 %, 2.64, 0.09), α = 0.720 (72.2 %, 100 %, -, 0.28). The heterogeneity index α is robust and can potentially help in staging and grading prediction in NPC. (orig.)

  7. Intravoxel water diffusion heterogeneity MR imaging of nasopharyngeal carcinoma using stretched exponential diffusion model

    International Nuclear Information System (INIS)

    Lai, Vincent; Khong, Pek Lan; Lee, Victor Ho Fun; Lam, Ka On; Sze, Henry Chun Kin; Chan, Queenie

    2015-01-01

    To determine the utility of stretched exponential diffusion model in characterisation of the water diffusion heterogeneity in different tumour stages of nasopharyngeal carcinoma (NPC). Fifty patients with newly diagnosed NPC were prospectively recruited. Diffusion-weighted MR imaging was performed using five b values (0-2,500 s/mm 2 ). Respective stretched exponential parameters (DDC, distributed diffusion coefficient; and alpha (α), water heterogeneity) were calculated. Patients were stratified into low and high tumour stage groups based on the American Joint Committee on Cancer (AJCC) staging for determination of the predictive powers of DDC and α using t test and ROC curve analyses. The mean ± standard deviation values were DDC = 0.692 ± 0.199 (x 10 -3 mm 2 /s) for low stage group vs 0.794 ± 0.253 (x 10 -3 mm 2 /s) for high stage group; α = 0.792 ± 0.145 for low stage group vs 0.698 ± 0.155 for high stage group. α was significantly lower in the high stage group while DDC was negatively correlated. DDC and α were both reliable independent predictors (p < 0.001), with α being more powerful. Optimal cut-off values were (sensitivity, specificity, positive likelihood ratio, negative likelihood ratio) DDC = 0.692 x 10 -3 mm 2 /s (94.4 %, 64.3 %, 2.64, 0.09), α = 0.720 (72.2 %, 100 %, -, 0.28). The heterogeneity index α is robust and can potentially help in staging and grading prediction in NPC. (orig.)

  8. Diffusion tensor image registration using hybrid connectivity and tensor features.

    Science.gov (United States)

    Wang, Qian; Yap, Pew-Thian; Wu, Guorong; Shen, Dinggang

    2014-07-01

    Most existing diffusion tensor imaging (DTI) registration methods estimate structural correspondences based on voxelwise matching of tensors. The rich connectivity information that is given by DTI, however, is often neglected. In this article, we propose to integrate complementary information given by connectivity features and tensor features for improved registration accuracy. To utilize connectivity information, we place multiple anchors representing different brain anatomies in the image space, and define the connectivity features for each voxel as the geodesic distances from all anchors to the voxel under consideration. The geodesic distance, which is computed in relation to the tensor field, encapsulates information of brain connectivity. We also extract tensor features for every voxel to reflect the local statistics of tensors in its neighborhood. We then combine both connectivity features and tensor features for registration of tensor images. From the images, landmarks are selected automatically and their correspondences are determined based on their connectivity and tensor feature vectors. The deformation field that deforms one tensor image to the other is iteratively estimated and optimized according to the landmarks and their associated correspondences. Experimental results show that, by using connectivity features and tensor features simultaneously, registration accuracy is increased substantially compared with the cases using either type of features alone. Copyright © 2013 Wiley Periodicals, Inc.

  9. Comparison of quality control software tools for diffusion tensor imaging.

    Science.gov (United States)

    Liu, Bilan; Zhu, Tong; Zhong, Jianhui

    2015-04-01

    Image quality of diffusion tensor imaging (DTI) is critical for image interpretation, diagnostic accuracy and efficiency. However, DTI is susceptible to numerous detrimental artifacts that may impair the reliability and validity of the obtained data. Although many quality control (QC) software tools are being developed and are widely used and each has its different tradeoffs, there is still no general agreement on an image quality control routine for DTIs, and the practical impact of these tradeoffs is not well studied. An objective comparison that identifies the pros and cons of each of the QC tools will be helpful for the users to make the best choice among tools for specific DTI applications. This study aims to quantitatively compare the effectiveness of three popular QC tools including DTI studio (Johns Hopkins University), DTIprep (University of North Carolina at Chapel Hill, University of Iowa and University of Utah) and TORTOISE (National Institute of Health). Both synthetic and in vivo human brain data were used to quantify adverse effects of major DTI artifacts to tensor calculation as well as the effectiveness of different QC tools in identifying and correcting these artifacts. The technical basis of each tool was discussed, and the ways in which particular techniques affect the output of each of the tools were analyzed. The different functions and I/O formats that three QC tools provide for building a general DTI processing pipeline and integration with other popular image processing tools were also discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Diffusion weighted MR imaging of pancreatic islet cell tumors

    International Nuclear Information System (INIS)

    Bakir, Baris; Salmaslioglu, Artur; Poyanli, Arzu; Rozanes, Izzet; Acunas, Bulent

    2010-01-01

    Purpose: The aim of our study is to demonstrate the feasibility of body diffusion weighted (DW) MR imaging in the evaluation of pancreatic islet cell tumors (ICTs) and to define apparent diffusion coefficient (ADC) values for these tumors. Materials and methods: 12 normal volunteers and 12 patients with histopathologically proven pancreatic ICT by surgery were included in the study. DW MR images were obtained by a body-phased array coil using a multisection single-shot echo planar sequence on the axial plane without breath holding. In addition, the routine abdominal imaging protocol for pancreas was applied in the patient group. We measured the ADC value within the normal pancreas in control group, pancreatic ICT, and surrounding pancreas parenchyma. Mann-Whitney U-test has been used to compare ADC values between tumoral tissues and normal pancreatic tissues of the volunteers. Wilcoxon Signed Ranks Test was preferred to compare ADC values between tumoral tissues and surrounding pancreatic parenchyma of the patients. Results: In 11 patients out of 12, conventional MR sequences were able to demonstrate ICTs successfully. In 1 patient an indistinct suspicious lesion was noted at the pancreatic tail. DW sequence was able to demonstrate the lesions in all of the 12 patients. On the DW images, all ICTs demonstrated high signal intensity relative to the surrounding pancreatic parenchyma. The mean and standard deviations of the ADC values (x10 -3 mm 2 /s) were as follows: ICT (n = 12), 1.51 ± 0.35 (0.91-2.11), surrounding parenchyma (n = 11) 0.76 ± 0.15 (0.51-1.01) and normal pancreas in normal volunteers (n = 12), 0.80 ± 0.06 (0.72-0.90). ADC values of the ICT were significantly higher compared with those of surrounding parenchyma (p < 0.01) and normal pancreas (p < 0.001). Conclusion: DW MR imaging does not appear to provide significant contribution to routine MR imaging protocol in the evaluation of pancreatic islet cell tumors. But it can be added to MR imaging

  11. Modeling the diffusion magnetic resonance imaging signal inside neurons

    International Nuclear Information System (INIS)

    Nguyen, D V; Li, J R; Grebenkov, D S; Le Bihan, D

    2014-01-01

    The Bloch-Torrey partial differential equation (PDE) describes the complex transverse water proton magnetization due to diffusion-encoding magnetic field gradient pulses. The integral of the solution of this PDE yields the diffusion magnetic resonance imaging (dMRI) signal. In a complex medium such as cerebral tissue, it is difficult to explicitly link the dMRI signal to biological parameters such as the cellular geometry or the cellular volume fraction. Studying the dMRI signal arising from a single neuron can provide insight into how the geometrical structure of neurons influences the measured signal. We formulate the Bloch-Torrey PDE inside a single neuron, under no water exchange condition with the extracellular space, and show how to reduce the 3D simulation in the full neuron to a 3D simulation around the soma and 1D simulations in the neurites. We show that this latter approach is computationally much faster than full 3D simulation and still gives accurate results over a wide range of diffusion times

  12. Diffusion-weighted magnetic resonance imaging of the abdomen

    International Nuclear Information System (INIS)

    Schmid-Tannwald, C.; Reiser, M.F.; Zech, C.J.

    2011-01-01

    Diffusion-weighted magnetic resonance imaging (DW-MRI) provides qualitative and quantitative information of tissue cellularity and the integrity of cellular membranes. Since DW-MRI can be performed without ionizing radiation exposure and contrast media application, DW-MRI is a particularly attractive tool for patients with allergies for gadolinium-based contrast agents or renal failure. Recent technical developments have made DW-MRI a robust and feasible technique for abdominal imaging. DW-MRI provides information on the detection and characterization of focal liver lesions and can also visualize treatment effects and early changes in chronic liver disease. In addition DW-MRI is a promising tool for the detection of inflammatory changes in patients with Crohn's disease. (orig.) [de

  13. Diffusion-weighted MR imaging in transient ischaemic attacks

    Energy Technology Data Exchange (ETDEWEB)

    Lamy, C.; Calvet, D.; Domigo, V.; Mas, J. [de l' Hopital Sainte-Anne, Service de Neurologie, Paris Cedex 14 (France); Oppenheim, C.; Naggara, O.; Meder, J.F. [Hoepital Sainte-Anne, Departement d' Imagere Morphologique et Fonchonnille, Paris (France)

    2006-05-15

    The purpose of this study was to determine frequency and the characteristics of diffusion-weighted imaging (DWI) abnormalities in patients with transient ischaemic attack (TIA). We analysed data of 98 consecutive patients (mean age: 60.6{+-}15.4 years, 56 men) admitted between January 2003 and April 2004 for TIA. Age, gender, symptom type and duration, delay from onset to magnetic resonance imaging (MRI), probable or possible TIA and cause of TIA were compared in patients with (DWI+) and without (DWI-) lesions on DWI. Volume and apparent diffusion coefficient (ADC) values of DWI lesions were computed. DWI revealed ischaemic lesions in 34 patients (34.7%). Lesions were small (mean volume: 1.9 cm{sup 3}{+-}3.3), and ADC was moderately decreased (mean ADC ratio: 79.5%). The diagnosis of TIA was considered as probable in all DWI+ patients. A multiple logistic regression model demonstrated that TIA duration greater than or equal to 60 min (OR, 7.6; 95% CI, 2.3-25.7), aphasia (OR, 9.2; 95% CI, 2.7-31.4) and motor deficit (OR, 5.1; 95% CI, 1.5-17.8) were independent predictors of DWI lesions. Prolonged TIA duration, aphasia and motor deficits are associated with DWI lesions. More than half of TIA patients with symptoms lasting more than 60 min have DWI lesions. (orig.)

  14. Diffusion-weighted MR imaging in transient ischaemic attacks

    International Nuclear Information System (INIS)

    Lamy, C.; Calvet, D.; Domigo, V.; Mas, J.; Oppenheim, C.; Naggara, O.; Meder, J.F.

    2006-01-01

    The purpose of this study was to determine frequency and the characteristics of diffusion-weighted imaging (DWI) abnormalities in patients with transient ischaemic attack (TIA). We analysed data of 98 consecutive patients (mean age: 60.6±15.4 years, 56 men) admitted between January 2003 and April 2004 for TIA. Age, gender, symptom type and duration, delay from onset to magnetic resonance imaging (MRI), probable or possible TIA and cause of TIA were compared in patients with (DWI+) and without (DWI-) lesions on DWI. Volume and apparent diffusion coefficient (ADC) values of DWI lesions were computed. DWI revealed ischaemic lesions in 34 patients (34.7%). Lesions were small (mean volume: 1.9 cm 3 ±3.3), and ADC was moderately decreased (mean ADC ratio: 79.5%). The diagnosis of TIA was considered as probable in all DWI+ patients. A multiple logistic regression model demonstrated that TIA duration greater than or equal to 60 min (OR, 7.6; 95% CI, 2.3-25.7), aphasia (OR, 9.2; 95% CI, 2.7-31.4) and motor deficit (OR, 5.1; 95% CI, 1.5-17.8) were independent predictors of DWI lesions. Prolonged TIA duration, aphasia and motor deficits are associated with DWI lesions. More than half of TIA patients with symptoms lasting more than 60 min have DWI lesions. (orig.)

  15. Diffusion-weighted MR imaging of transplanted kidneys: Preliminary report.

    Science.gov (United States)

    Wypych-Klunder, Katarzyna; Adamowicz, Andrzej; Lemanowicz, Adam; Szczęsny, Wojciech; Włodarczyk, Zbigniew; Serafin, Zbigniew

    2014-01-01

    An aim of this study was to assess the feasibility of DWI in the early period after kidney transplantation. We also aimed to compare ADC and eADC values in the cortex and medulla of the kidney, to estimate image noise and variability of measurements, and to verify possible relation between selected labolatory results and diffusion parameters in the transplanted kidney. Examinations were performed using a 1.5 T MR unit. DWI (SE/EPI) was performed in the axial plane using b-values of 600 and 1000. ADC and eADC measurements were performed in four regions of interest within the renal cortex and in three regions within the medulla. Relative variability of results and signal-to-noise ratio (SNR) were calculated. The analysis included 15 patients (mean age 52 years). The mean variability of ADC was significantly lower than that of eADC (6.8% vs. 10.8%, respectively; p30 ml/min./1.73 m(2) (p<0.05). Diffusion-weighted imaging of transplanted kidneys is technically challenging, especially in patients in the early period after transplantation. From a technical point of view, the best quality parameters offer quality ADC measurement in the renal cortex using b1000. ADC and eADC values in the renal cortex measured at b1000 present a relationship with eGFR.

  16. Diffusion-weighted imaging in normal fetal brain maturation

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, J.F. [University Children' s Hospital UKBB, Department of Pediatric Radiology, Basel (Switzerland); Confort-Gouny, S.; Le Fur, Y.; Viout, P.; Cozzone, P. [UMR-CNRS 6612, Faculte de Medecine, Universite de la Mediterranee, Centre de Resonance Magnetique Biologique et Medicale, Marseille (France); Bennathan, M.; Chapon, F.; Fogliarini, C.; Girard, N. [Universite de la Mediterranee, Department of Neuroradiology AP-HM Timone, Marseille (France)

    2007-09-15

    Diffusion-weighted imaging (DWI) provides information about tissue maturation not seen on conventional magnetic resonance imaging. The aim of this study is to analyze the evolution over time of the apparent diffusion coefficient (ADC) of normal fetal brain in utero. DWI was performed on 78 fetuses, ranging from 23 to 37 gestational weeks (GW). All children showed at follow-up a normal neurological evaluation. ADC values were obtained in the deep white matter (DWM) of the centrum semiovale, the frontal, parietal, occipital and temporal lobe, in the cerebellar hemisphere, the brainstem, the basal ganglia (BG) and the thalamus. Mean ADC values in supratentorial DWM areas (1.68 {+-} 0.05 mm{sup 2}/s) were higher compared with the cerebellar hemisphere (1.25 {+-} 0.06 mm{sup 2}/s) and lowest in the pons (1.11 {+-} 0.05 mm{sup 2}/s). Thalamus and BG showed intermediate values (1.25 {+-} 0.04 mm{sup 2}/s). Brainstem, cerebellar hemisphere and thalamus showed a linear negative correlation with gestational age. Supratentorial areas revealed an increase in ADC values, followed by a decrease after the 30th GW. This study provides a normative data set that allows insights in the normal fetal brain maturation in utero, which has not yet been observed in previous studies on premature babies. (orig.)

  17. Diffusion-weighted imaging in characterization of cystic pancreatic lesions

    Energy Technology Data Exchange (ETDEWEB)

    Sandrasegaran, K., E-mail: ksandras@iupui.edu [Department of Radiology, Indiana University School of Medicine, Indianapolis, IN (United States); Akisik, F.M.; Patel, A.A.; Rydberg, M. [Department of Radiology, Indiana University School of Medicine, Indianapolis, IN (United States); Cramer, H.M.; Agaram, N.P. [Department of Pathology, Indiana University School of Medicine, Indianapolis, IN (United States); Schmidt, C.M. [Department of Surgery, Indiana University School of Medicine, Indianapolis, IN (United States)

    2011-09-15

    Aim: To evaluate whether apparent diffusion coefficient (ADC) measurements from diffusion-weighted imaging (DWI) can characterize or predict the malignant potential of cystic pancreatic lesions. Materials and methods: Retrospective review of the magnetic resonance imaging (MRI) database over a 2-year period revealed 136 patients with cystic pancreatic lesions. Patients with DWI studies and histological confirmation of cystic mass were included. In patients with known pancreatitis, lesions with amylase content of >1000 IU/l that resolved on subsequent scans were included as pseudocysts. ADC of cystic lesions was measured by two independent reviewers. These values were then compared to categorize these lesions as benign or malignant using conventional MRI sequences. Results: Seventy lesions were analysed: adenocarcinoma (n = 4), intraductal papillary mucinous neoplasm (IPMN; n = 28), mucinous cystic neoplasm (MCN; n = 9), serous cystadenoma (n = 16), and pseudocysts (n = 13). There was no difference between ADC values of malignant and non-malignant lesions (p = 0.06), between mucinous and serous tumours (p = 0.12), or between IPMN and MCN (p = 0.42). ADC values for low-grade IPMN were significantly higher than those for high-grade or invasive IPMN (p = 0.03). Conclusion: ADC values may be helpful in deciding the malignant potential of IPMN. However, they are not useful in differentiating malignant from benign lesions or for characterizing cystic pancreatic lesions.

  18. Assessment of vasogenic edema in eclampsia using diffusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Engelter, S.T. [Department of Radiology, Duke University Medical Center, Durham, NC (United States); Division of Neurology, Duke University Medical Center, Durham, North Carolina (United States); Provenzale, J.M.; Petrella, J.R. [Department of Radiology, Duke University Medical Center, Durham, NC (United States)

    2000-11-01

    We qualitatively assessed the regional distribution of vasogenic edema in a case of postpartum eclampsia. Although diffusion-weighted imaging showed no abnormalities, bilateral high signal was seen on T2-weighted images and apparent diffusion coefficient (ADC) maps. ADC of 1.45 {+-} 0.10 mm{sup 2}/s x 10{sup -3} for the posterior cerebral artery (PCA) territory and 1.22 {+-} 0.12 mm{sup 2}/s x 10{sup -3} for the watershed areas were significantly higher than those in the territories of the anterior (0.85 {+-} 0.07 mm{sup 2}/s x 10{sup -3}) and middle cerebral (0.79 {+-} 0.06 mm{sup 2}/s x 10{sup -3})arteries (P < 0.05). The predilection of ADC changes within the PCA territory and in a previously undescribed watershed distribution supports the hypothesis that vasogenic edema in eclampsia is due to hypertension-induced failure of vascular autoregulation. (orig.)

  19. Assessing the future of diffuse optical imaging technologies for breast cancer management

    International Nuclear Information System (INIS)

    Tromberg, Bruce J.; Pogue, Brian W.; Paulsen, Keith D.; Yodh, Arjun G.; Boas, David A.; Cerussi, Albert E.

    2008-01-01

    Diffuse optical imaging (DOI) is a noninvasive optical technique that employs near-infrared (NIR) light to quantitatively characterize the optical properties of thick tissues. Although NIR methods were first applied to breast transillumination (also called diaphanography) nearly 80 years ago, quantitative DOI methods employing time- or frequency-domain photon migration technologies have only recently been used for breast imaging (i.e., since the mid-1990s). In this review, the state of the art in DOI for breast cancer is outlined and a multi-institutional Network for Translational Research in Optical Imaging (NTROI) is described, which has been formed by the National Cancer Institute to advance diffuse optical spectroscopy and imaging (DOSI) for the purpose of improving breast cancer detection and clinical management. DOSI employs broadband technology both in near-infrared spectral and temporal signal domains in order to separate absorption from scattering and quantify uptake of multiple molecular probes based on absorption or fluorescence contrast. Additional dimensionality in the data is provided by integrating and co-registering the functional information of DOSI with x-ray mammography and magnetic resonance imaging (MRI), which provide structural information or vascular flow information, respectively. Factors affecting DOSI performance, such as intrinsic and extrinsic contrast mechanisms, quantitation of biochemical components, image formation/visualization, and multimodality co-registration are under investigation in the ongoing research NTROI sites. One of the goals is to develop standardized DOSI platforms that can be used as stand-alone devices or in conjunction with MRI, mammography, or ultrasound. This broad-based, multidisciplinary effort is expected to provide new insight regarding the origins of breast disease and practical approaches for addressing several key challenges in breast cancer, including: Detecting disease in mammographically dense tissue

  20. Diffusion-weighted magnetic resonance imaging in autoimmune pancreatitis

    International Nuclear Information System (INIS)

    Taniguchi, Takao; Kobayashi, Hisato; Nishikawa, Koji; Iida, Etsushi; Michigami, Yoshihiro; Morimoto, Emiko; Yamashita, Rikiya; Miyagi, Ken; Okamoto, Motozumi

    2009-01-01

    The aim of this study was to investigate the usefulness of diffusion-weighted magnetic resonance imaging (DWI MRI) for the diagnosis and evaluation of autoimmune pancreatitis (AIP). A total of 4 consecutive patients with AIP, 5 patients with chronic alcoholic pancreatitis (CP), and 13 patients without pancreatic disease (controls) were studied. DWI was performed in the axial plane with spin-echo echo-planar imaging single-shot sequence. Apparent diffusion coefficients (ADCs) were measured in circular regions of interest in the pancreas. In AIP patients, abdominal MRI was performed before, and 2-4 weeks after steroid treatment. Follow-up study was performed chronologically for up to 11 months in two patients. The correlation between ADCs of the pancreas and the immunoglobulin G4 (IgG4) index (serum IgG4 value/serum IgG4 value before steroid treatment) was evaluated. In the AIP patients, DWI of the pancreas showed high signal intensity, and the ADCs of the pancreas (mean±standard deviation (SD): 0.97±0.18 x 10 -3 mm 2 /s) were significantly lower than those in patients with CP (1.45±0.10 x 10 -3 mm 2 /s) or the controls (1.45±0.16 x 10 -3 mm 2 /s) (Mann-Whitney U-test, P s =-0.80, P<0.05). Autoimmune pancreatitis showed high signal intensity on DWI, which improved after steroid treatment. ADCs reflected disease activity. Thus, diffusion-weighted MRI might be useful for diagnosing AIP, determining the affected area, and evaluating the effect of treatment. (author)

  1. Portable laser-induced breakdown spectroscopy/diffuse reflectance hybrid spectrometer for analysis of inorganic pigments

    Science.gov (United States)

    Siozos, Panagiotis; Philippidis, Aggelos; Anglos, Demetrios

    2017-11-01

    A novel, portable spectrometer, combining two analytical techniques, laser-induced breakdown spectroscopy (LIBS) and diffuse reflectance spectroscopy, was developed with the aim to provide an enhanced instrumental and methodological approach with regard to the analysis of pigments in objects of cultural heritage. Technical details about the hybrid spectrometer and its operation are presented and examples are given relevant to the analysis of paint materials. Both LIBS and diffuse reflectance spectra in the visible and part of the near infrared, corresponding to several neat mineral pigment samples, were recorded and the complementary information was used to effectively distinguish different types of pigments even if they had similar colour or elemental composition. The spectrometer was also employed in the analysis of different paints on the surface of an ancient pottery sherd demonstrating the capabilities of the proposed hybrid diagnostic approach. Despite its instrumental simplicity and compact size, the spectrometer is capable of supporting analytical campaigns relevant to archaeological, historical or art historical investigations, particularly when quick data acquisition is required in the context of surveys of large numbers of objects and samples.

  2. Diffuse reflectance spectroscopy for monitoring diabetic foot ulcer - A pilot study

    Science.gov (United States)

    Anand, Suresh; Sujatha, N.; Narayanamurthy, V. B.; Seshadri, V.; Poddar, Richa

    2014-02-01

    Foot ulceration due to diabetes mellitus is a major problem affecting 12-25% of diabetic subjects in their lifetime. An untreated ulcer further gets infected which causes necrosis leading to amputation of lower extremities. Early identification of risk factors and treatment for these chronic wounds would reduce health care costs and improve the quality of life for people with diabetes. Recent clinical investigations have shown that a series of factors including reduced oxygen delivery and disturbed metabolism have been observed on patients with foot ulceration due to diabetes. Also, these factors can impair the wound healing process. Optical techniques based on diffuse reflectance spectroscopy provide characteristic spectral finger prints shed light on tissue oxygenation levels and morphological composition of a tissue. This study deals with the application of diffuse reflectance intensity ratios based on oxyhemoglobin bands (R542/R580), ratios of oxy- and deoxy-hemoglobin bands (R580/R555), total hemoglobin concentration and hemoglobin oxygen saturation between normal and diabetic foot ulcer sites. Preliminary results obtained are found to be promising indicating the application of reflectance spectroscopy in the assessment of foot ulcer healing.

  3. Diffusion-weighted imaging of the pancreas; Diffusionsbildgebung des Pankreas

    Energy Technology Data Exchange (ETDEWEB)

    Gruenberg, K. [Deutsches Krebsforschungszentrum (DKFZ) Heidelberg, Abteilung Radiologie, E010, Heidelberg (Germany); Grenacher, L.; Klauss, M. [Universitaetsklinikum Heidelberg, Abt. Diagnostische und Interventionelle Radiologie, Heidelberg (Germany)

    2011-03-15

    Diffusion-weighted imaging (DWI) has increasingly gained in importance over the last 10 years especially in cancer imaging for differentiation of malignant and benign lesions. Through development of fast magnetic resonance imaging (MRI) sequences DWI is not only applicable in neuroradiology but also in abdominal imaging. As a diagnostic tool of the pancreas DWI enables a differentiation between normal tissue, cancer and chronic pancreatitis. The ADC values (apparent diffusion coefficient, the so-called effective diffusion coefficient) reported in the literature for healthy pancreatic tissue are in the range from 1.49 to 1.9 x 10{sup -3} mm{sup 2}/s, for pancreatic cancer in the range from 1.24 to 1.46 x 10{sup -3} mm{sup 2}/s and for autoimmune pancreatitis an average ADC value of 1.012 x 10{sup -3} mm{sup 2}/s. There are controversial data in the literature concerning the differentiation between chronic pancreatitis and pancreatic cancer. Using DWI-derived IVIM (intravoxel incoherent motion) the parameter f (perfusion fraction) seems to be advantageous but it is important to use several b values. In the literature the mean f value in chronic pancreatitis is around 16%, in pancreatic cancer 8% and in healthy pancreatic tissue around 25%. So far, DWI has not been helpful for differentiating cystic lesions of the pancreas. There are many references with other tumor entities and in animal models which indicate that there is a possible benefit of DWI in monitoring therapy of pancreatic cancer but so far no original work has been published. (orig.) [German] Die Diffusionsbildgebung (''diffusion-weighted imaging'', DWI) gewann in den letzten 10 Jahren insbesondere in der Tumorbildgebung zur Unterscheidung zwischen malignen und benignen Laesionen zunehmend an Bedeutung. Durch Entwicklung schnellerer MR-Sequenzen ist sie nicht nur in der Neuroradiologie, sondern auch in der Abdomenbildgebung einsetzbar. In der Pankreasdiagnostik ermoeglicht sie

  4. Photoelectron Imaging Spectroscopy as a Window to Unexpected Molecules

    Science.gov (United States)

    Blackstone, Christopher C.

    2017-06-01

    Targeting an anion with the formula CH_{3}O_{3} for exploration with photoelectron imaging spectroscopy, we determine its identity to be dihydroxymethanolate, an anion largely absent in the literature, and the conjugate base of the hypothetical species orthoformic acid. Comparing the observed photoelectron spectrum to CCSD-EOM-IP and CCSD-EOM-SF calculations completed in QChem and Franck-Condon overlap simulations in PESCAL, we are able to determine with confidence the connectivity of the atoms in this molecule.

  5. Performance assessment of diffuse optical spectroscopic imaging instruments in a 2-year multicenter breast cancer trial

    Science.gov (United States)

    Leproux, Anaïs; O'Sullivan, Thomas D.; Cerussi, Albert; Durkin, Amanda; Hill, Brian; Hylton, Nola; Yodh, Arjun G.; Carp, Stefan A.; Boas, David; Jiang, Shudong; Paulsen, Keith D.; Pogue, Brian; Roblyer, Darren; Yang, Wei; Tromberg, Bruce J.

    2017-12-01

    We present a framework for characterizing the performance of an experimental imaging technology, diffuse optical spectroscopic imaging (DOSI), in a 2-year multicenter American College of Radiology Imaging Network (ACRIN) breast cancer study (ACRIN-6691). DOSI instruments combine broadband frequency-domain photon migration with time-independent near-infrared (650 to 1000 nm) spectroscopy to measure tissue absorption and reduced scattering spectra and tissue hemoglobin, water, and lipid composition. The goal of ACRIN-6691 was to test the effectiveness of optically derived imaging endpoints in predicting the final pathologic response of neoadjuvant chemotherapy (NAC). Sixty patients were enrolled over a 2-year period at participating sites and received multiple DOSI scans prior to and during 3- to 6-month NAC. The impact of three sources of error on accuracy and precision, including different operators, instruments, and calibration standards, was evaluated using a broadband reflectance standard and two different solid tissue-simulating optical phantoms. Instruments showed <0.0010 mm-1 (10.3%) and 0.06 mm-1 (4.7%) deviation in broadband absorption and reduced scattering, respectively, over the 2-year duration of ACRIN-6691. These variations establish a useful performance criterion for assessing instrument stability. The proposed procedures and tests are not limited to DOSI; rather, they are intended to provide methods to characterize performance of any instrument used in translational optical imaging.

  6. Diffusion and spectroscopy of water and lipids in fully hydrated dimyristoylphosphatidylcholine bilayer membranes

    International Nuclear Information System (INIS)

    Yang, J.; Martí, J.; Calero, C.

    2014-01-01

    Microscopic structure and dynamics of water and lipids in a fully hydrated dimyristoylphosphatidylcholine phospholipid lipid bilayer membrane in the liquid-crystalline phase have been analyzed with all-atom molecular dynamics simulations based on the recently parameterized CHARMM36 force field. The diffusive dynamics of the membrane lipids and of its hydration water, their reorientational motions as well as their corresponding spectral densities, related to the absorption of radiation, have been considered for the first time using the present force field. In addition, structural properties such as density and pressure profiles, a deuterium-order parameter, surface tension, and the extent of water penetration in the membrane have been analyzed. Molecular self-diffusion, reorientational motions, and spectral densities of atomic species reveal a variety of time scales playing a role in membrane dynamics. The mechanisms of lipid motion strongly depend on the time scale considered, from fast ballistic translation at the scale of picoseconds (effective diffusion coefficients of the order of 10 −5 cm 2 /s) to diffusive flow of a few lipids forming nanodomains at the scale of hundreds of nanoseconds (diffusion coefficients of the order of 10 −8 cm 2 /s). In the intermediate regime of sub-diffusion, collisions with nearest neighbors prevent the lipids to achieve full diffusion. Lipid reorientations along selected directions agree well with reported nuclear magnetic resonance data and indicate two different time scales, one about 1 ns and a second one in the range of 2–8 ns. We associated the two time scales of reorientational motions with angular distributions of selected vectors. Calculated spectral densities corresponding to lipid and water reveal an overall good qualitative agreement with Fourier transform infrared spectroscopy experiments. Our simulations indicate a blue-shift of the low frequency spectral bands of hydration water as a result of its interaction

  7. Diffusion and spectroscopy of water and lipids in fully hydrated dimyristoylphosphatidylcholine bilayer membranes

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J.; Martí, J., E-mail: jordi.marti@upc.edu [Department of Physics and Nuclear Engineering, Technical University of Catalonia-Barcelona Tech, B4-B5 Northern Campus, Jordi Girona 1-3, 08034 Barcelona, Catalonia (Spain); Calero, C. [Department of Physics and Nuclear Engineering, Technical University of Catalonia-Barcelona Tech, B4-B5 Northern Campus, Jordi Girona 1-3, 08034 Barcelona, Catalonia (Spain); Center for Polymer Studies, Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215 (United States)

    2014-03-14

    Microscopic structure and dynamics of water and lipids in a fully hydrated dimyristoylphosphatidylcholine phospholipid lipid bilayer membrane in the liquid-crystalline phase have been analyzed with all-atom molecular dynamics simulations based on the recently parameterized CHARMM36 force field. The diffusive dynamics of the membrane lipids and of its hydration water, their reorientational motions as well as their corresponding spectral densities, related to the absorption of radiation, have been considered for the first time using the present force field. In addition, structural properties such as density and pressure profiles, a deuterium-order parameter, surface tension, and the extent of water penetration in the membrane have been analyzed. Molecular self-diffusion, reorientational motions, and spectral densities of atomic species reveal a variety of time scales playing a role in membrane dynamics. The mechanisms of lipid motion strongly depend on the time scale considered, from fast ballistic translation at the scale of picoseconds (effective diffusion coefficients of the order of 10{sup −5} cm{sup 2}/s) to diffusive flow of a few lipids forming nanodomains at the scale of hundreds of nanoseconds (diffusion coefficients of the order of 10{sup −8} cm{sup 2}/s). In the intermediate regime of sub-diffusion, collisions with nearest neighbors prevent the lipids to achieve full diffusion. Lipid reorientations along selected directions agree well with reported nuclear magnetic resonance data and indicate two different time scales, one about 1 ns and a second one in the range of 2–8 ns. We associated the two time scales of reorientational motions with angular distributions of selected vectors. Calculated spectral densities corresponding to lipid and water reveal an overall good qualitative agreement with Fourier transform infrared spectroscopy experiments. Our simulations indicate a blue-shift of the low frequency spectral bands of hydration water as a result of

  8. Terahertz time-domain spectroscopy and imaging of artificial RNA

    DEFF Research Database (Denmark)

    Fischer, Bernd M.; Hoffmann, Matthias; Helm, Hanspeter

    2005-01-01

    We use terahertz time-domain spectroscopy (THz-TDS) to measure the far-infrared dielectric function of two artificial RNA single strands, composed of polyadenylic acid (poly-A) and polycytidylic acid (poly-C). We find a significant difference in the absorption between the two types of RNA strands......, and we show that we can use this difference to record images of spot arrays of the RNA strands. Under controlled conditions it is possible to use the THz image to distinguish between the two RNA strands. We discuss the requirements to sample preparation imposed by the lack of sharp spectral features...

  9. Monitoring of caffeine consumption effect on skin blood properties by diffuse reflectance spectroscopy

    Science.gov (United States)

    Milanic, Matija; Marin, Ana; Stergar, Jost; Verdel, Nina; Majaron, Boris

    2017-07-01

    Caffeine is the most widely consumed psychoactive substance in the world. It affects many tissues and organs, in particular central nervous system, heart, and blood vessels. The effect of caffeine on vascular smooth muscle cells is an initial transient contraction followed by significant vasodilatation. In this study we investigate the use of diffuse reflectance spectroscopy (DRS) for monitoring of vascular changes in human skin induced by caffeine consumption. DRS spectra were recorded on volar sides of the forearms of ten healthy volunteers at time delays of 0, 30, 60, 120, and 180 minutes after consumption of caffeine, while one subject served as a negative control. Analytical diffusion approximation solutions for diffuse reflectance from three-layer structures were used to assess skin composition (e.g., dermal blood volume fraction and oxygen saturation) by fitting to experimental data. The results demonstrate that cutaneous vasodynamics induced by caffeine consumption can be monitored by DRS, while changes in the control subject not consuming caffeine were insignificant.

  10. Automated sample preparation station for studying self-diffusion in porous solids with NMR spectroscopy

    Science.gov (United States)

    Hedin, Niklas; DeMartin, Gregory J.; Reyes, Sebastián C.

    2006-03-01

    In studies of gas diffusion in porous solids with nuclear magnetic resonance (NMR) spectroscopy the sample preparation procedure becomes very important. An apparatus is presented here that pretreats the sample ex situ and accurately sets the desired pressure and temperature within the NMR tube prior to its introduction in the spectrometer. The gas manifold that supplies the NMR tube is also connected to a microbalance containing another portion of the same sample, which is kept at the same temperature as the sample in the NMR tube. This arrangement permits the simultaneous measurement of the adsorption loading on the sample, which is required for the interpretation of the NMR diffusion experiments. Furthermore, to ensure a good seal of the NMR tube, a hybrid valve design composed of titanium, a Teflon® seat, and Kalrez® O-rings is utilized. A computer controlled algorithm ensures the accuracy and reproducibility of all the procedures, enabling the NMR diffusion experiments to be performed at well controlled conditions of pressure, temperature, and amount of gas adsorbed on the porous sample.

  11. Cancer Metabolism and Tumor Heterogeneity: Imaging Perspectives Using MR Imaging and Spectroscopy

    OpenAIRE

    Lin, Gigin; Keshari, Kayvan R.; Park, Jae Mo

    2017-01-01

    Cancer cells reprogram their metabolism to maintain viability via genetic mutations and epigenetic alterations, expressing overall dynamic heterogeneity. The complex relaxation mechanisms of nuclear spins provide unique and convertible tissue contrasts, making magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) pertinent imaging tools in both clinics and research. In this review, we summarized MR methods that visualize tumor characteristics and its metabolic phenotypes ...

  12. Diffusion weighted MR imaging of transient ischemic attacks

    International Nuclear Information System (INIS)

    Chung, Jin Il; Kim, Dong Ik; Lee, Seung Ik; Yoon, Pyung Ho; Heo, Ji Hoe; Lee, Byung In

    2000-01-01

    To investigate the findings of diffusion-weighted MR imaging in patients with transient ischemic attacks (TIA). Between August 1996 and June 1999, 41 TIA patients (M:F =3D 28:13, mean age 57 (range, 27-75) years) with neurologic symptoms lasting less than 24 hours underwent diffusion-weighted MR imaging. The time interval between the onset of symptoms and MR examination was less than one week in 29 patients, from one week to one month in eight, and undetermined in four. Conventional MR and DWI were compared in terms of location of infarction and lesion size (less than 1 cm, 1-3 cm, greater than 3 cm), and we also determined the anatomical vascular territory of acute stroke lesions and possible etiologic mechanisms. The findings of DWI were normal in 24/41 patients (58.5%), while 15 (36.6%) showed acute ischemic lesions. The other two showed old lacunar infarcts. All acute and old DWI lesions were revealed by conventional MR imaging. Among the 15 acute stroke patients, seven had small vessel lacunar disease. In three patients, the infarction was less than 1 cm in size. Six patients showed large vessel infarction in the territory of the MCA, PCA, and PICA; the size of this was less than 1 cm in three patients, 1-3 cm in two, and more than 3 cm in one. In two patients, embolic infarction of cardiac origin in the territory of the MCA and AICA was diagnosed. The possible mechanism of TIA is still undetermined, but acute lesions revealed by DWI in TIA patients tend, in any case, to be small and multiple. (author)

  13. Simultaneous analysis and quality assurance for diffusion tensor imaging.

    Directory of Open Access Journals (Sweden)

    Carolyn B Lauzon

    Full Text Available Diffusion tensor imaging (DTI enables non-invasive, cyto-architectural mapping of in vivo tissue microarchitecture through voxel-wise mathematical modeling of multiple magnetic resonance imaging (MRI acquisitions, each differently sensitized to water diffusion. DTI computations are fundamentally estimation processes and are sensitive to noise and artifacts. Despite widespread adoption in the neuroimaging community, maintaining consistent DTI data quality remains challenging given the propensity for patient motion, artifacts associated with fast imaging techniques, and the possibility of hardware changes/failures. Furthermore, the quantity of data acquired per voxel, the non-linear estimation process, and numerous potential use cases complicate traditional visual data inspection approaches. Currently, quality inspection of DTI data has relied on visual inspection and individual processing in DTI analysis software programs (e.g. DTIPrep, DTI-studio. However, recent advances in applied statistical methods have yielded several different metrics to assess noise level, artifact propensity, quality of tensor fit, variance of estimated measures, and bias in estimated measures. To date, these metrics have been largely studied in isolation. Herein, we select complementary metrics for integration into an automatic DTI analysis and quality assurance pipeline. The pipeline completes in 24 hours, stores statistical outputs, and produces a graphical summary quality analysis (QA report. We assess the utility of this streamlined approach for empirical quality assessment on 608 DTI datasets from pediatric neuroimaging studies. The efficiency and accuracy of quality analysis using the proposed pipeline is compared with quality analysis based on visual inspection. The unified pipeline is found to save a statistically significant amount of time (over 70% while improving the consistency of QA between a DTI expert and a pool of research associates. Projection of QA

  14. Characterization of Soft Tissue Tumors by Diffusion-Weighted Imaging

    International Nuclear Information System (INIS)

    Pekcevik, Yeliz; Kahya, Mehmet Onur; Kaya, Ahmet

    2015-01-01

    Diffusion-weighted imaging (DWI) is a noninvasive method for investigation of tumor histological content. It has been applied for some musculoskeletal tumors and reported to be useful. The aim of the present study was to prospectively evaluate the apparent diffusion coefficient (ADC) values of benign and malignant soft tissue tumors and to determine if ADC can help differentiate these tumors. DWI was performed on 25 histologically proven soft tissue masses. It was obtained with a single-shot echo-planar imaging technique using a 1.5T magnetic resonance (MR) machine. The mean ADC values were calculated. We grouped soft tissue tumors as benign cystic, benign solid or mixed, malignant cystic and malignant solid or mixed tumors and compared mean ADC values between these groups. There was only one patient with a malignant cystic tumor and was not included in the statistical analysis. The median ADC values of benign and malignant tumors were 2.31 ± 1.29 and 0.90 ± 0.70 (median ± interquartile range), respectively. The mean ADC values were different between benign and malignant tumors (P = 0.031). Benign cystic tumors had significantly higher ADC values than benign solid or mixed tumors and malignant solid or mixed tumors (p values were < 0.001 and 0.003, respectively). Malignant solid or mixed tumors had lower ADC values than benign solid or mixed tumors (P = 0.02). Our preliminary results have shown that although there is some overlap between benign and malignant tumors, adding DWI, MR imaging to routine soft tissue tumor protocols may improve diagnostic accuracy

  15. Exploiting Optical Contrasts for Cervical Precancer Diagnosis via Diffuse Reflectance Spectroscopy

    Science.gov (United States)

    Chang, Vivide Tuan-Chyan

    collagen without altering the amount of collagen present. Further work would be required to elucidate the exact sources of scattering contrast observed. Common confounding variables that limit the accuracy and clinical acceptability of optical spectroscopic systems are calibration requirements and variable probe-tissue contact pressures. Our results suggest that using a real-time self-calibration channel, as opposed to conventional post-experiment diffuse reflectance standard calibration measurements, significantly improved data integrity for the extraction of scattering contrast. Extracted [total Hb] and scattering were also significantly associated with applied contact probe pressure in colposcopically normal sites. Hence, future contact probe spectroscopy or imaging systems should incorporate a self-calibration channel and ensure spectral acquisition at a consistent contact pressure to collect reliable data with enhanced absorption and scattering contrasts. Another method to enhance optical contrast is to selectively interrogate different depths in the dysplastic cervix. For instance, scattering has been shown to increase in the epithelium (increase in nuclear-to-cytoplasmic ratio) while decrease in the stroma (re-organization of the extra-cellular matrix and changes in of collagen fiber cross-links). A fiber-optic probe with 45° illumination and collection fibers with a separation distance of 330 μm was designed and constructed to selectively interrogate the cervical epithelium. Mean extraction errors from liquid phantoms with optical properties mimicking the cervical epithelium for μa and μs' were 11.3 % and 12.7 %, respectively. Diffuse reflectance spectra from 9 sites in four loop electrosurgical excision procedure (LEEP) patients were analyzed. Preliminary data demonstrate the utility of the oblique fiber geometry in extracting scattering contrast in the cervical epithelium. Further work is needed to study the systematic error in optical property extraction and

  16. Diagnostic performance of conventional diffusion weighted imaging and diffusion tensor imaging for the liver fibrosis and inflammation

    International Nuclear Information System (INIS)

    Tosun, Mesude; Inan, Nagihan; Sarisoy, Hasan Tahsin; Akansel, Gur; Gumustas, Sevtap; Gürbüz, Yeşim; Demirci, Ali

    2013-01-01

    Objective: To evaluate the diagnostic accuracy of liver apparent diffusion coefficient (ADC) measured with conventional diffusion-weighted imaging (CDI) and diffusion tensor imaging (DTI) for the diagnosis of liver fibrosis and inflammation. Materials and methods: Thirty-seven patients with histologic diagnosis of chronic viral hepatitis and 34 healthy volunteers were included in this prospective study. All patients and healthy volunteers were examined by 3 T MRI. CDI and DTI were performed using a breath-hold single-shot echo-planar spin echo sequence with b factors of 0 and 1000 s/mm 2 . ADCs were obtained with CDI and DTI. Histopathologically, fibrosis of the liver parenchyma was classified with the use of a 5-point scale (0–4) and inflammation was classified with use of a 4-point scale (0–3) in accordance with the METAVIR score. Quantitatively, signal intensity and the ADCs of the liver parenchyma were compared between patients stratified by fibrosis stage and inflammation grade. Results: With a b factor of 1000 s/mm 2 , the signal intensity of the cirrhotic livers was significantly higher than those of the normal volunteers. In addition, ADCs reconstructed from CDI and DTI of the patients were significantly lower than those of the normal volunteers. Liver ADC values inversely correlated with fibrosis and inflammation but there was only statistically significant for inflammatory grading. CDI performed better than DTI for the diagnosis of fibrosis and inflammation. Conclusion: ADC values measured with CDI and DTI may help in the detection of liver fibrosis. They may also give contributory to the inflammatory grading, particularly in distinguishing high from low grade

  17. Diagnostic performance of conventional diffusion weighted imaging and diffusion tensor imaging for the liver fibrosis and inflammation

    Energy Technology Data Exchange (ETDEWEB)

    Tosun, Mesude, E-mail: mesude.tosun@kocaeli.edu.tr [Department of Radiology, School of Medicine, University of Kocaeli (Turkey); Inan, Nagihan, E-mail: inannagihan@ekolay.net [Department of Radiology, School of Medicine, University of Kocaeli (Turkey); Sarisoy, Hasan Tahsin, E-mail: htssarisoy@yahoo.com [Department of Radiology, School of Medicine, University of Kocaeli (Turkey); Akansel, Gur, E-mail: gakansel@gmail.com [Department of Radiology, School of Medicine, University of Kocaeli (Turkey); Gumustas, Sevtap, E-mail: svtgumustas@hotmail.com [Department of Radiology, School of Medicine, University of Kocaeli (Turkey); Gürbüz, Yeşim, E-mail: yesimgurbuz2002@yahoo.com [Department of Pathology, School of Medicine, University of Kocaeli (Turkey); Demirci, Ali, E-mail: alidemirci@kocaeli.edu.tr [Department of Radiology, School of Medicine, University of Kocaeli (Turkey)

    2013-02-15

    Objective: To evaluate the diagnostic accuracy of liver apparent diffusion coefficient (ADC) measured with conventional diffusion-weighted imaging (CDI) and diffusion tensor imaging (DTI) for the diagnosis of liver fibrosis and inflammation. Materials and methods: Thirty-seven patients with histologic diagnosis of chronic viral hepatitis and 34 healthy volunteers were included in this prospective study. All patients and healthy volunteers were examined by 3 T MRI. CDI and DTI were performed using a breath-hold single-shot echo-planar spin echo sequence with b factors of 0 and 1000 s/mm{sup 2}. ADCs were obtained with CDI and DTI. Histopathologically, fibrosis of the liver parenchyma was classified with the use of a 5-point scale (0–4) and inflammation was classified with use of a 4-point scale (0–3) in accordance with the METAVIR score. Quantitatively, signal intensity and the ADCs of the liver parenchyma were compared between patients stratified by fibrosis stage and inflammation grade. Results: With a b factor of 1000 s/mm{sup 2}, the signal intensity of the cirrhotic livers was significantly higher than those of the normal volunteers. In addition, ADCs reconstructed from CDI and DTI of the patients were significantly lower than those of the normal volunteers. Liver ADC values inversely correlated with fibrosis and inflammation but there was only statistically significant for inflammatory grading. CDI performed better than DTI for the diagnosis of fibrosis and inflammation. Conclusion: ADC values measured with CDI and DTI may help in the detection of liver fibrosis. They may also give contributory to the inflammatory grading, particularly in distinguishing high from low grade.

  18. Diffusion

    International Nuclear Information System (INIS)

    Kubaschewski, O.

    1983-01-01

    The diffusion rate values of titanium, its compounds and alloys are summarized and tabulated. The individual chemical diffusion coefficients and self-diffusion coefficients of certain isotopes are given. Experimental methods are listed which were used for the determination of diffusion coefficients. Some values have been taken over from other studies. Also given are graphs showing the temperature dependences of diffusion and changes in the diffusion coefficient with concentration changes

  19. Diffusion Weighted Imaging in Acute Attacks of Multiple Sclerosis

    International Nuclear Information System (INIS)

    Davoudi, Yasmin; Foroughipour, Mohsen; Torabi, Reza; Layegh, Parvaneh; Matin, Nassim; Shoeibi, Ali

    2016-01-01

    Multiple sclerosis (MS) is one of the most common autoimmune disorders of the central nervous system. In spite of various imaging modalities, the definitive diagnosis of MS remains challenging. This study was designed to evaluate the usefulness of diffusion weighted imaging (DWI) in the diagnosis of acute MS attack and to compare its results with contrast enhanced MRI (CE-MRI). In this cross sectional study, seventy patients with definite diagnosis of relapsing-remitting MS were included. CE-MRI using 0.1 mmol/kg gadolinium as well as DWI sequences were performed for all patients. The percentage of patients with positive DWI was compared with the results of CE-MRI and the consistency between the two imaging modalities was evaluated. Moreover, the relationship between the time of onset of patient’s symptoms and test results for both methods were investigated. CE-MRI yielded positive results for 61 (87%) patients and DWI yielded positive for 53 (76%) patients. In fifty patients (71.42%), both tests were positive and in six cases (8.57%), both were negative. The test results of three patients turned out to be positive in DWI, while they tested negative in CE-MRI. There was no significant relationship between the results of CE-MRI as well as DWI and the time of imaging from the onset of symptoms. These data indicate that while CE-MRI will depict more positive results, there are cases in which DWI will show a positive result while CE-MRI is negative. We suggest that the combination of these two imaging modalities might yield more positive results in diagnosing acute MS attack giving rise to a more accurate diagnosis

  20. Diffuse Optical Tomography for Brain Imaging: Continuous Wave Instrumentation and Linear Analysis Methods

    Science.gov (United States)

    Giacometti, Paolo; Diamond, Solomon G.

    Diffuse optical tomography (DOT) is a functional brain imaging technique that measures cerebral blood oxygenation and blood volume changes. This technique is particularly useful in human neuroimaging measurements because of the coupling between neural and hemodynamic activity in the brain. DOT is a multichannel imaging extension of near-infrared spectroscopy (NIRS). NIRS uses laser sources and light detectors on the scalp to obtain noninvasive hemodynamic measurements from spectroscopic analysis of the remitted light. This review explains how NIRS data analysis is performed using a combination of the modified Beer-Lambert law (MBLL) and the diffusion approximation to the radiative transport equation (RTE). Laser diodes, photodiode detectors, and optical terminals that contact the scalp are the main components in most NIRS systems. Placing multiple sources and detectors over the surface of the scalp allows for tomographic reconstructions that extend the individual measurements of NIRS into DOT. Mathematically arranging the DOT measurements into a linear system of equations that can be inverted provides a way to obtain tomographic reconstructions of hemodynamics in the brain.

  1. Online quantitative monitoring of live cell engineered cartilage growth using diffuse fiber-optic Raman spectroscopy.

    Science.gov (United States)

    Bergholt, Mads S; Albro, Michael B; Stevens, Molly M

    2017-09-01

    Tissue engineering (TE) has the potential to improve the outcome for patients with osteoarthritis (OA). The successful clinical translation of this technique as part of a therapy requires the ability to measure extracellular matrix (ECM) production of engineered tissues in vitro, in order to ensure quality control and improve the likelihood of tissue survival upon implantation. Conventional techniques for assessing the ECM content of engineered cartilage, such as biochemical assays and histological staining are inherently destructive. Raman spectroscopy, on the other hand, represents a non-invasive technique for in situ biochemical characterization. Here, we outline current roadblocks in translational Raman spectroscopy in TE and introduce a comprehensive workflow designed to non-destructively monitor and quantify ECM biomolecules in large (>3 mm), live cell TE constructs online. Diffuse near-infrared fiber-optic Raman spectra were measured from live cell cartilaginous TE constructs over a 56-day culturing period. We developed a multivariate curve resolution model that enabled quantitative biochemical analysis of the TE constructs. Raman spectroscopy was able to non-invasively quantify the ECM components and showed an excellent correlation with biochemical assays for measurement of collagen (R 2  = 0.84) and glycosaminoglycans (GAGs) (R 2  = 0.86). We further demonstrated the robustness of this technique for online prospective analysis of live cell TE constructs. The fiber-optic Raman spectroscopy strategy developed in this work offers the ability to non-destructively monitor construct growth online and can be adapted to a broad range of TE applications in regenerative medicine toward controlled clinical translation. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  2. Cerebral Fat Embolism: Diffusion-weighted Magnetic Resonance Imaging Findings

    International Nuclear Information System (INIS)

    Ryu, C.W.

    2005-01-01

    PURPOSE: To demonstrate the diffusion-weighted (DWI) magnetic resonance imaging (MRI) findings, and the follow-up MRI findings, of cerebral fat embolism in the acute stage. MATERIAL AND METHODS: The initial DWI and clinical findings of six patients with cerebral fat embolism were retrospectively evaluated. The finding of DWI with a b-value of 1000 s/mm 2 (b=1000) was compared with that of DWI with a b-value of 0 s/mm 2 (b=0). In three patients who underwent follow-up MRI, the interval change of the lesion on T2-weighted images was investigated. RESULTS: The characteristic DWI finding of cerebral fat embolism in the acute stage was multiple, hyperintense, dot-like lesions disseminated in the brain. These lesions were distributed dominantly in the bilateral border-zone areas. Some lesions had an ancillary location including the cortex, deep white matter, basal ganglia, and cerebellum. The lesions were more intense and numerous in DWI (b=1000) than in DWI (b=0). The findings on the follow-up T2-weighted images were multiple confluent hyperintense lesions in the white matter with progression since the initial MRI. CONCLUSION: DWI could be a sensitive tool for detecting cerebral fat embolism in the acute phase. It is recommended that DWI be included in the initial evaluation of cerebral fat embolism with MRI

  3. Homogeneity based segmentation and enhancement of Diffusion Tensor Images : a white matter processing framework

    OpenAIRE

    Rodrigues, P.R.

    2011-01-01

    In diffusion magnetic resonance imaging (DMRI) the Brownian motion of the water molecules, within biological tissue, is measured through a series of images. In diffusion tensor imaging (DTI) this diffusion is represented using tensors. DTI describes, in a non-invasive way, the local anisotropy pattern enabling the reconstruction of the nervous fibers - dubbed tractography. DMRI constitutes a powerful tool to analyse the structure of the white matter within a voxel, but also to investigate the...

  4. Diffusion-weighted MR imaging of the normal fetal lung

    International Nuclear Information System (INIS)

    Balassy, Csilla; Kasprian, Gregor; Weber, Michael; Hoermann, Marcus; Bankier, Alexander; Herold, Christian J.; Prayer, Daniela; Brugger, Peter C.; Csapo, Bence; Bammer, Roland

    2008-01-01

    To quantify apparent diffusion coefficient (ADC) changes in fetuses with normal lungs and to determine whether ADC can be used in the assessment of fetal lung development. In 53 pregnancies (20-37th weeks of gestation), we measured ADC on diffusion-weighted imaging (DWI) in the apical, middle, and basal thirds of the right lung. ADCs were correlated with gestational age. Differences between the ADCs were assessed. Fetal lung volumes were measured on T2-weighted sequences and correlated with ADCs and with age. ADCs were 2.13 ± 0.44 μm 2 /ms (mean ± SD) in the apex, 1.99 ± 0.42 μm 2 /ms (mean ± SD) in the middle third, and 1.91 ± 0.41 μm 2 /ms (mean ± SD) in the lung base. Neither the individual ADC values nor average ADC values showed a significant correlation with gestational age or with lung volumes. Average ADCs decreased significantly from the lung apex toward the base. Individual ADCs showed little absolute change and heterogeneity. Lung volumes increased significantly during gestation. We have not been able to identify a pattern of changes in the ADC values that correlate with lung maturation. Furthermore, the individual, gravity-related ADC changes are subject to substantial variability and show nonuniform behavior. ADC can therefore not be used as an indicator of lung maturity. (orig.)

  5. Longitudinal diffusion tensor imaging in amyotrophic lateral sclerosis

    Directory of Open Access Journals (Sweden)

    Keil Carsten

    2012-11-01

    Full Text Available Abstract Background Amyotrophic lateral sclerosis (ALS is a fatal neurodegenerative disorder, caused by progressive loss of motor neurons. Changes are widespread in the subcortical white matter in ALS. Diffusion tensor imaging (DTI detects pathological changes in white matter fibres in vivo, based on alterations in the degree (diffusivity, ADC and directedness (fractional anisotropy, FA of proton movement. Methods 24 patients with ALS and 24 age-matched controls received 1.5T DTI. FA and ADC were analyzed using statistical parametric mapping. In 15 of the 24 ALS patients, a second DTI was obtained after 6 months. Results Decreased FA in the corticospinal tract (CST and frontal areas confirm existing results. With a direct comparison of baseline and follow-up dataset, the progression of upper motor neuron degeneration, reflected in FA decrease, could be captured along the CST and in frontal areas. The involvement of cerebellum in the pathology of ALS, as suspected from functional MRI studies, could be confirmed by a reduced FA (culmen, declive. These structural changes correlated well with disease duration, ALSFRS-R, and physical and executive functions. Conclusion DTI detects changes that are regarded as prominent features of ALS and thus, shows promise in its function as a biomarker. Using the technique herein, we could demonstrate DTI changes at follow-up which correlated well with clinical progression.

  6. Diffusion-weighted MR imaging of the normal fetal lung

    Energy Technology Data Exchange (ETDEWEB)

    Balassy, Csilla; Kasprian, Gregor; Weber, Michael; Hoermann, Marcus; Bankier, Alexander; Herold, Christian J.; Prayer, Daniela [Medical University of Vienna, Department of Radiology, Vienna (Austria); Brugger, Peter C. [Medical University of Vienna, Center of Anatomy and Cell Biology, Vienna (Austria); Csapo, Bence [Medical University of Vienna, Department of Obstetrics and Gyneocology, Vienna (Austria); Bammer, Roland [University of Stanford, Department of Radiology, Stanford, CA (United States)

    2008-04-15

    To quantify apparent diffusion coefficient (ADC) changes in fetuses with normal lungs and to determine whether ADC can be used in the assessment of fetal lung development. In 53 pregnancies (20-37th weeks of gestation), we measured ADC on diffusion-weighted imaging (DWI) in the apical, middle, and basal thirds of the right lung. ADCs were correlated with gestational age. Differences between the ADCs were assessed. Fetal lung volumes were measured on T2-weighted sequences and correlated with ADCs and with age. ADCs were 2.13 {+-} 0.44 {mu}m{sup 2}/ms (mean {+-} SD) in the apex, 1.99 {+-} 0.42 {mu}m{sup 2}/ms (mean {+-} SD) in the middle third, and 1.91 {+-} 0.41 {mu}m{sup 2}/ms (mean {+-} SD) in the lung base. Neither the individual ADC values nor average ADC values showed a significant correlation with gestational age or with lung volumes. Average ADCs decreased significantly from the lung apex toward the base. Individual ADCs showed little absolute change and heterogeneity. Lung volumes increased significantly during gestation. We have not been able to identify a pattern of changes in the ADC values that correlate with lung maturation. Furthermore, the individual, gravity-related ADC changes are subject to substantial variability and show nonuniform behavior. ADC can therefore not be used as an indicator of lung maturity. (orig.)

  7. Thin-Section Diffusion-Weighted Magnetic Resonance Imaging of the Brain with Parallel Imaging

    International Nuclear Information System (INIS)

    Oner, A.Y.; Celik, H.; Tali, T.; Akpek, S.; Tokgoz, N.

    2007-01-01

    Background: Thin-section diffusion-weighted imaging (DWI) is known to improve lesion detectability, with long imaging time as a drawback. Parallel imaging (PI) is a technique that takes advantage of spatial sensitivity information inherent in an array of multiple-receiver surface coils to partially replace time-consuming spatial encoding and reduce imaging time. Purpose: To prospectively evaluate a 3-mm-thin-section DWI technique combined with PI by means of qualitative and quantitative measurements. Material and Methods: 30 patients underwent conventional echo-planar (EPI) DWI (5-mm section thickness, 1-mm intersection gap) without parallel imaging, and thin-section EPI-DWI with PI (3-mm section thickness, 0-mm intersection gap) for a b value of 1000 s/mm 2 , with an imaging time of 40 and 80 s, respectively. Signal-to-noise ratio (SNR), relative signal intensity (rSI), and apparent diffusion coefficient (ADC) values were measured over a lesion-free cerebral region on both series by two radiologists. A quality score was assigned for each set of images to assess the image quality. When a brain lesion was present, contrast-to-noise ratio (CNR) and corresponding ADC were also measured. Student t-tests were used for statistical analysis. Results: Mean SNR values of the normal brain were 33.61±4.35 and 32.98±7.19 for conventional and thin-slice DWI (P>0.05), respectively. Relative signal intensities were significantly higher on thin-section DWI (P 0.05). Quality scores and overall lesion CNR were found to be higher in thin-section DWI with parallel imaging. Conclusion: A thin-section technique combined with PI improves rSI, CNR, and image quality without compromising SNR and ADC measurements in an acceptable imaging time. Keywords: Brain; DWI; parallel imaging; thin section

  8. Neuropsychological Correlates of Diffusion Tensor Imaging in Schizophrenia

    Science.gov (United States)

    Nestor, Paul G.; Kubicki, Marek; Gurrera, Ronald J.; Niznikiewicz, Margaret; Frumin, Melissa; McCarley, Robert W.; Shenton, Martha E.

    2009-01-01

    Patients with schizophrenia (n = 41) and healthy comparison participants (n = 46) completed neuropsychological measures of intelligence, memory, and executive function. A subset of each group also completed magnetic resonance diffusion tensor imaging (DTI) studies (fractional anisotropy and cross-sectional area) of the uncinate fasciculus (UF) and cingulate bundle (CB). Patients with schizophrenia showed reduced levels of functioning across all neuropsychological measures. In addition, selective neuropsychological–DTI relationships emerged. Among patients but not controls, lower levels of declarative–episodic verbal memory correlated with reduced left UF, whereas executive function errors related to performance monitoring correlated with reduced left CB. The data suggested abnormal DTI patterns linking declarative–episodic verbal memory deficits to the left UF and executive function deficits to the left CB among patients with schizophrenia. PMID:15506830

  9. Diffusion magnetic resonance imaging in transient global amnesia

    Energy Technology Data Exchange (ETDEWEB)

    Godeiro-Junior, Clecio; Miranda-Alves, Maramelia Araujo de [Federal University of Sao Paulo (UNIFESP-EPM), Sao Paulo SP (Brazil). Dept. of Neurology and Neurosurgery], e-mail: cleciojunior@yahoo.com.br; Massaro, Ayrton Roberto [Fleury Diagnostic Center, Sao Paulo SP (Brazil)

    2009-03-15

    Transient global amnesia (TGA) is a well known clinical entity characterized by anterograde memory disturbance of sudden onset that lasts 1 to 24 hours. Orientation in space and time is impaired while consciousness remains undisturbed. TGA may refer to a single expression of several physiopathological phenomena. Conceptually, cerebral ischemia, epileptic discharge, and migraine constitute the main pathogenic hypothesis. Diffusion-weighted imaging (DWI) has become a powerful tool in the evaluation of patients with suspected stroke owing to its high sensitivity and specificity, even for small areas of acute ischemia. Consequently, this method has also been applied to TGA to gain further insights into the ischemic hypothesis of this condition. We report a patient with a typical TGA presentation and MRI findings suggestive of an ischemic insult. We further discuss the ischemic hypothesis of TGA. (author)

  10. Diffusion magnetic resonance imaging in transient global amnesia

    International Nuclear Information System (INIS)

    Godeiro-Junior, Clecio; Miranda-Alves, Maramelia Araujo de

    2009-01-01

    Transient global amnesia (TGA) is a well known clinical entity characterized by anterograde memory disturbance of sudden onset that lasts 1 to 24 hours. Orientation in space and time is impaired while consciousness remains undisturbed. TGA may refer to a single expression of several physiopathological phenomena. Conceptually, cerebral ischemia, epileptic discharge, and migraine constitute the main pathogenic hypothesis. Diffusion-weighted imaging (DWI) has become a powerful tool in the evaluation of patients with suspected stroke owing to its high sensitivity and specificity, even for small areas of acute ischemia. Consequently, this method has also been applied to TGA to gain further insights into the ischemic hypothesis of this condition. We report a patient with a typical TGA presentation and MRI findings suggestive of an ischemic insult. We further discuss the ischemic hypothesis of TGA. (author)

  11. Data of NODDI diffusion metrics in the brain and computer simulation of hybrid diffusion imaging (HYDI acquisition scheme

    Directory of Open Access Journals (Sweden)

    Chandana Kodiweera

    2016-06-01

    Full Text Available This article provides NODDI diffusion metrics in the brains of 52 healthy participants and computer simulation data to support compatibility of hybrid diffusion imaging (HYDI, “Hybrid diffusion imaging” [1] acquisition scheme in fitting neurite orientation dispersion and density imaging (NODDI model, “NODDI: practical in vivo neurite orientation dispersion and density imaging of the human brain” [2]. HYDI is an extremely versatile diffusion magnetic resonance imaging (dMRI technique that enables various analyzes methods using a single diffusion dataset. One of the diffusion data analysis methods is the NODDI computation, which models the brain tissue with three compartments: fast isotropic diffusion (e.g., cerebrospinal fluid, anisotropic hindered diffusion (e.g., extracellular space, and anisotropic restricted diffusion (e.g., intracellular space. The NODDI model produces microstructural metrics in the developing brain, aging brain or human brain with neurologic disorders. The first dataset provided here are the means and standard deviations of NODDI metrics in 48 white matter region-of-interest (ROI averaging across 52 healthy participants. The second dataset provided here is the computer simulation with initial conditions guided by the first dataset as inputs and gold standard for model fitting. The computer simulation data provide a direct comparison of NODDI indices computed from the HYDI acquisition [1] to the NODDI indices computed from the originally proposed acquisition [2]. These data are related to the accompanying research article “Age Effects and Sex Differences in Human Brain White Matter of Young to Middle-Aged Adults: A DTI, NODDI, and q-Space Study” [3].

  12. In-utero three dimension high resolution fetal brain diffusion tensor imaging.

    Science.gov (United States)

    Jiang, Shuzhou; Xue, Hui; Counsell, Serena; Anjari, Mustafa; Allsop, Joanna; Rutherford, Mary; Rueckert, Daniel; Hajnal, Joseph V

    2007-01-01

    We present a methodology to achieve 3D high resolution in-utero fetal brain DTI that shows excellent ADC as well as promising FA maps. After continuous DTI scanning to acquire a repeated series of parallel slices with 15 diffusion directions, image registration is used to realign the images to correct for fetal motion. Once aligned, the diffusion images are treated as irregularly sampled data where each voxel is associated with an appropriately rotated diffusion direction, and used to estimate the diffusion tensor on a regular grid. The method has been tested successful on eight fetuses and has been validated on adults imaged at 1.5T.

  13. Clinical study of diffusion weighted imaging in nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Chen Yunbin; Mao Yu; Pan Jianji; Hu Chunmiao

    2009-01-01

    Objective: To determine the diagnostic value of diffusion weighted imaging (DWI) for primary nasopharyngeal carcinoma(NPC) and metastatic lymph nodes, and to establish the diagnostic threshold of apparent diffusion coefficients(ADCs). Methods: Conventional MR scans and DWI scans were continuously performed in 56 patients with newly diagnosed NPC and 55 healthy volunteers. All patients received primary tumor biopsy and MR image-guided cervical lymph node fine-needle biopsy. ADC and eADC values of both primary lesions and lymph nodes were calculated and compared. Results: According to the pathological diagnosis, all the 56 patients had non-keratinizing carcinoma and 51 had lymph node metastasis. In the control group, 75 cervical lymph nodes were found. ADC values of both primary NPC and metastatic lymph nodes were significantly lower, while eADC values were higher than those of normal controls. Setting the ADC value threshold at 0.809 x 10 -3 mm 2 /s, the sensitivity and specificity for primary NPC detection were 80.4% and 74.5%, respectively. The negative and positive predictive values were 79.2% and 77.6%, respectively. The accuracy was 78.4%. Setting the ADC value threshold at 0.708 x 10 -3 mm 2 /s, the sensitivity and specificity in the detection of metastatic cervical lymph nodes were 43.1% and 93.3%, respectively. The negative and positive predictive values were 70.7% and 81.5%, respectively. The accuracy was 73.0%. Conclusions: DWI might be a new diagnostic approach in the detection of primary NPC as well as metastatic lymph nodes. (authors)

  14. Diffusion tensor imaging in polymicrogyria: a report of three cases

    International Nuclear Information System (INIS)

    Trivedi, R.; Gupta, R.K.; Prasad, K.N.; Hasan, K.M.; Hou, P.; Narayana, P.A.

    2006-01-01

    Polymicrogyria (PMG), a neuronal migration disorder, commonly manifests as a seizure disorder. The aim of this study was to look for the abnormalities in the underlying white matter using diffusion tensor imaging (DTI) that appeared normal on conventional magnetic resonance imaging (MRI) in patients with PMG. DTI was performed in three patients with PMG and eight age- and sex-matched healthy controls. Fractional anisotropy (FA) and mean diffusivity (MD) values were calculated for the cortex and adjoining subcortical white matter in both controls and patients. We observed a significantly decreased mean FA value with no significant change in the MD value in subcortical white matter underlying polymicrogyric cortex (FA=0.23±0.04, MD=1.0±0.05 x 10 -3 mm 2 /s) as compared to both contralateral (FA=0.32±0.04, MD=1.0±0.05 x 10 -3 mm 2 /s) and normal control (FA=0.32±0.04, MD=1.0±0.06 x 10 -3 mm 2 /s) white matter. Significantly increased MD and decreased FA values were also observed in the polymicrogyric cortex (FA=0.08±0.01, MD=1.2±0.10 x 10 -3 mm 2 /s) as compared to normal contralateral (FA=0.12±0.04, MD=1.1±0.09 x 10 -3 mm 2 /s) and normal control (FA=0.12±0.01, MD=1.1±0.09 x 10 -3 mm 2 /s) cortex. Significantly decreased FA values with no change in MD values in the subcortical white matter subjacent to polymicrogyric cortex reflect microstructural changes in the white matter probably due to the presence of ectopic neurons. (orig.)

  15. Role of Infrared Spectroscopy and Imaging in Cancer Diagnosis.

    Science.gov (United States)

    Kumar, Saroj; Srinivasan, Alagiri; Nikolajeff, Fredrik

    2018-01-01

    Cancer is a major global health issue. It causes extensive individual suffering and gives a huge burden on the health care in society. Despite extensive research and different tools have been developed it still remains a challenge for early detection of this disease. FTIR imaging has been used to diagnose and differentiate the molecular differences between normal and diseased tissues. Fourier Transform Infrared Spectroscopy (FTIR) is able to measure biochemical changes in tissue, cell and biofluids based on the vibrational signature of their components. This technique enables to the distribution and structure of lipids, proteins, nucleic acids as well as other metabolites. These differences depended on the type and the grade of cancer. We emphasize here, that the FTIR spectroscopy and imaging can be considered as a promising technique and will find its place on the detection of this dreadful disease because of high sensitivity, accuracy and inexpensive technique. Now the medical community started using and accepting this technique for early stage cancer detection. We discussed this technique and the several challenges in its application for the diagnosis of cancer in regards of sample preparations, data interpretation, and data analysis. The sensitivity of chemotherapy drugs on individual specific has also discussed. So far progressed has done with the FTIR imaging in understanding of cancer disease pathology. However, more research is needed in this field and it is necessary to understand the morphology and biology of the sample before using the spectroscopy and imaging because invaluable information to be figured out. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  16. Evaluation of apparent viscosity of Para rubber latex by diffuse reflection near-infrared spectroscopy.

    Science.gov (United States)

    Sirisomboon, Panmanas; Chowbankrang, Rawiphan; Williams, Phil

    2012-05-01

    Near-infrared spectroscopy in diffuse reflection mode was used to evaluate the apparent viscosity of Para rubber field latex and concentrated latex over the wavelength range of 1100 to 2500 nm, using partial least square regression (PLSR). The model with ten principal components (PCs) developed using the raw spectra accurately predicted the apparent viscosity with correlation coefficient (r), standard error of prediction (SEP), and bias of 0.974, 8.6 cP, and -0.4 cP, respectively. The ratio of the SEP to the standard deviation (RPD) and the ratio of the SEP to the range (RER) for the prediction were 4.4 and 16.7, respectively. Therefore, the model can be used for measurement of the apparent viscosity of field latex and concentrated latex in quality assurance and process control in the factory.

  17. Experimental analysis of bruises in human volunteers using radiometric depth profiling and diffuse reflectance spectroscopy

    Science.gov (United States)

    Vidovič, Luka; Milanič, Matija; Majaron, Boris

    2015-07-01

    We combine pulsed photothermal radiometry (PPTR) depth profiling with diffuse reflectance spectroscopy (DRS) measurements for a comprehensive analysis of bruise evolution in vivo. While PPTR enables extraction of detailed depth distribution and concentration profiles of selected absorbers (e.g. melanin, hemoglobin), DRS provides information in a wide range of visible wavelengths and thus offers an additional insight into dynamics of the hemoglobin degradation products. Combining the two approaches enables us to quantitatively characterize bruise evolution dynamics. Our results indicate temporal variations of the bruise evolution parameters in the course of bruise self-healing process. The obtained parameter values and trends represent a basis for a future development of an objective technique for bruise age determination.

  18. Analysis of hemodynamics in human skin using photothermal radiometry and diffuse reflectance spectroscopy

    Science.gov (United States)

    Verdel, Nina; Marin, Ana; Vidovič, Luka; Milanič, Matija; Majaron, Boris

    2017-07-01

    We present a novel methodology for quantitative analysis of hemodynamics in human skin in vivo. Our approach combines pulsed photothermal radiometry (i.e., time-resolved measurements of midinfrared emission from sample surface after exposure to a short light pulse) and diffuse reflectance spectroscopy in visible part of the spectrum. Experimental data are fitted with predictions of a numerical model of light transport in a four-layer skin model (i.e., inverse Monte Carlo), which allows assessment of the layer thicknesses, chromophore contents (e.g., melanin, oxy- and deoxy-hemoglobin), as well as scattering properties. The performance is tested in comparison analysis of healthy skin before and during application of a blood pressure cuff (at 200 mm Hg) for 5 minutes.

  19. Craniocerebral trauma. Magnetic resonance imaging of diffuse axonal injury

    International Nuclear Information System (INIS)

    Mallouhi, A.

    2014-01-01

    Acceleration-deceleration rotational brain trauma is a common cause of disability or death in young adults and often leads to a focal destruction of axons. The resulting pathology, axonal shear injury is referred to as diffuse axonal injury (DAI). The DAI-associated lesions occur bilaterally, are widely dispersed and have been observed in the surface and deep white matter. They are found near to and far from the impact site. When DAI is clinically suspected, magnetic resonance imaging (MRI) is the method of choice for further clarification, especially in patients where cranial computed tomography (CT) is inconspicuous. To investigate the presence of DAI after traumatic brain injury (TBI), a multimodal MRI approach is applied including the common structural and also functional imaging sequences. For structural MRI, fluid-attenuated inversion recovery (FLAIR) weighted and susceptibility contrast imaging (SWI) are the sequences mainly used. The SWI technique is extremely sensitive to blood breakdown products, which appear as small signal voids at three locations, at the gray-white interface, in the corpus callosum and in the brain stem. Functional MRI comprises a group of constantly developing techniques that have great potential in optimal evaluation of the white matter in patients after craniocerebral trauma. These imaging techniques allow the visualization of changes associated with shear injuries, such as functional impairment of axons and decreased blood flow and abnormal metabolic activity of the brain parts affected. The multimodal MRI approach in patients with DAI results in a more detailed and differentiated representation of the underlying pathophysiological changes of the injured nerve tracts and helps to improve the diagnostic and prognostic accuracy of MRI. When DAI is suspected multimodal MRI should be performed as soon as possible after craniocerebral injury. (orig.) [de

  20. Raman spectroscopy and imaging: applications in human breast cancer diagnosis.

    Science.gov (United States)

    Brozek-Pluska, Beata; Musial, Jacek; Kordek, Radzislaw; Bailo, Elena; Dieing, Thomas; Abramczyk, Halina

    2012-08-21

    The applications of spectroscopic methods in cancer detection open new possibilities in early stage diagnostics. Raman spectroscopy and Raman imaging represent novel and rapidly developing tools in cancer diagnosis. In the study described in this paper Raman spectroscopy has been employed to examine noncancerous and cancerous human breast tissues of the same patient. The most significant differences between noncancerous and cancerous tissues were found in regions characteristic for the vibrations of carotenoids, lipids and proteins. Particular attention was paid to the role played by unsaturated fatty acids in the differentiation between the noncancerous and the cancerous tissues. Comparison of Raman spectra of the noncancerous and the cancerous tissues with the spectra of oleic, linoleic, α-linolenic, γ-linolenic, docosahexaenoic and eicosapentaenoic acids has been presented. The role of sample preparation in the determination of cancer markers is also discussed in this study.

  1. Histogram analysis of noise performance on fractional anisotropy brain MR image with different diffusion gradient numbers

    International Nuclear Information System (INIS)

    Chang, Yong Min; Kim, Yong Sun; Kang, Duk Sik; Lee, Young Joo; Sohn, Chul Ho; Woo, Seung Koo; Suh, Kyung Jin

    2005-01-01

    We wished to analyze, qualitatively and quantitatively, the noise performance of fractional anisotropy brain images along with the different diffusion gradient numbers by using the histogram method. Diffusion tensor images were acquired using a 3.0 T MR scanner from ten normal volunteers who had no neurological symptoms. The single-shot spin-echo EPI with a Stejskal-Tanner type diffusion gradient scheme was employed for the diffusion tensor measurement. With a b-valuee of 1000 s/mm 2 , the diffusion tensor images were obtained for 6, 11, 23, 35 and 47 diffusion gradient directions. FA images were generated for each DTI scheme. The histograms were then obtained at selected ROIs for the anatomical structures on the FA image. At the same ROI location, the mean FA value and the standard deviation of the mean FA value were calculated. The quality of the FA image was improved as the number of diffusion gradient directions increased by showing better contrast between the WM and GM. The histogram showed that the variance of FA values was reduced as the number of diffusion gradient directions increased. This histogram analysis was in good agreement with the result obtained using quantitative analysis. The image quality of the FA map was significantly improved as the number of diffusion gradient directions increased. The histogram analysis well demonstrated that the improvement in the FA images resulted from the reduction in the variance of the FA values included in the ROI

  2. T2-enhanced tensor diffusion trace-weighted image in the detection of hyper-acute cerebral infarction: Comparison with isotropic diffusion-weighted image

    International Nuclear Information System (INIS)

    Chou, M.-C.; Tzeng, W.-S.; Chung, H.-W.; Wang, C.-Y.; Liu, H.-S.; Juan, C.-J.; Lo, C.-P.; Hsueh, C.-J.; Chen, C.-Y.

    2010-01-01

    Background and purpose: Although isotropic diffusion-weighted imaging (isoDWI) is very sensitive to the detection of acute ischemic stroke, it may occasionally show diffusion negative result in hyper-acute stroke. We hypothesize that high diffusion contrast diffusion trace-weighted image with enhanced T2 may improve stroke lesion conspicuity. Methods: Five hyper acute stroke patients (M:F = 0:5, average age = 61.8 ± 20.5 y/o) and 16 acute stroke patients (M:F = 11:5, average age = 67.7 ± 12 y/o) were examined six-direction tensor DWIs at b = 707 s/mm 2 . Three different diffusion-weighted images, including isotropic (isoDWI), diffusion trace-weighted image (trDWI) and T2-enhanced diffusion trace-weighted image (T2E t rDWI), were generated. Normalized lesion-to-normal ratio (nLNR) and contrast-to-noise ratio (CNR) of three diffusion images were calculated from each patient and statistically compared. Results: The trDWI shows better nLNR than isoDWI on both hyper-acute and acute stroke lesions, whereas no significant improvement in CNR. Nevertheless, the T2E t rDWI has statistically superior CNR and nLNR than those of isoDWI and trDWI in both hyper-acute and acute stroke. Conclusions: We concluded that tensor diffusion trace-weighted image with T2 enhancement is more sensitive to stroke lesion detection, and can provide higher lesion conspicuity than the conventional isotropic DWI for early stroke lesion delineation without the need of high-b-value technique.

  3. Near-infrared imaging spectroscopy for counterfeit drug detection

    Science.gov (United States)

    Arnold, Thomas; De Biasio, Martin; Leitner, Raimund

    2011-06-01

    Pharmaceutical counterfeiting is a significant issue in the healthcare community as well as for the pharmaceutical industry worldwide. The use of counterfeit medicines can result in treatment failure or even death. A rapid screening technique such as near infrared (NIR) spectroscopy could aid in the search for and identification of counterfeit drugs. This work presents a comparison of two laboratory NIR imaging systems and the chemometric analysis of the acquired spectroscopic image data. The first imaging system utilizes a NIR liquid crystal tuneable filter and is designed for the investigation of stationary objects. The second imaging system utilizes a NIR imaging spectrograph and is designed for the fast analysis of moving objects on a conveyor belt. Several drugs in form of tablets and capsules were analyzed. Spectral unmixing techniques were applied to the mixed reflectance spectra to identify constituent parts of the investigated drugs. The results show that NIR spectroscopic imaging can be used for contact-less detection and identification of a variety of counterfeit drugs.

  4. Effects of MR parameter changes on the quantification of diffusion anisotropy and apparent diffusion coefficient in diffusion tensor imaging: Evaluation using a diffusional anisotropic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Joon; Choi, Choong Gon; Kim, Jeong Kon [Dept. of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Yun, Sung Cheol [Dept. of Biostatistics, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Jeong, Ha Kyu [Dept. of Radiology, East-West Neomedical Center, Kyung Hee University College of Medicine, Seoul (Korea, Republic of); Kim, Eun Ju [Clinical Scientist, MR, Philips Healthcare, Seoul (Korea, Republic of)

    2015-04-15

    To validate the usefulness of a diffusional anisotropic capillary array phantom and to investigate the effects of diffusion tensor imaging (DTI) parameter changes on diffusion fractional anisotropy (FA) and apparent diffusion coefficient (ADC) using the phantom. Diffusion tensor imaging of a capillary array phantom was performed with imaging parameter changes, including voxel size, number of sensitivity encoding (SENSE) factor, echo time (TE), number of signal acquisitions, b-value, and number of diffusion gradient directions (NDGD), one-at-a-time in a stepwise-incremental fashion. We repeated the entire series of DTI scans thrice. The coefficients of variation (CoV) were evaluated for FA and ADC, and the correlation between each MR imaging parameter and the corresponding FA and ADC was evaluated using Spearman's correlation analysis. The capillary array phantom CoVs of FA and ADC were 7.1% and 2.4%, respectively. There were significant correlations between FA and SENSE factor, TE, b-value, and NDGD, as well as significant correlations between ADC and SENSE factor, TE, and b-value. A capillary array phantom enables repeated measurements of FA and ADC. Both FA and ADC can vary when certain parameters are changed during diffusion experiments. We suggest that the capillary array phantom can be used for quality control in longitudinal or multicenter clinical studies.

  5. Application of diffusion ordered-1H-nuclear magnetic resonance spectroscopy to quantify sucrose in beverages.

    Science.gov (United States)

    Cao, Ruge; Nonaka, Airi; Komura, Fusae; Matsui, Toshiro

    2015-03-15

    This work focuses on a quantitative analysis of sucrose using diffusion ordered-quantitative (1)H-nuclear magnetic resonance spectroscopy (DOSY-qNMR), where an analyte can be isolated from interference based on its characteristic diffusion coefficient (D) in gradient magnetic fields. The D value of sucrose in deuterium oxide at 30°C was 4.9 × 10(-10)m(2)/s at field gradient pulse from 5.0 × 10(-2) to 3.0 × 10(-1)T/m, separated from other carbohydrates (glucose and fructose). Good linearity (r(2)=0.9999) was obtained between sucrose (0.5-20.0 g/L) and the resonance area of target glucopyranosyl-α-C1 proton normalised to that of cellobiose C1 proton (100.0 g/L, as an internal standard) in 1D sliced DOSY spectrum. The DOSY-qNMR method was successfully applied to quantify sucrose in orange juice (36.1 ± 0.5 g/L), pineapple juice (53.5 ± 1.1g/L) and a sports drink (24.7 ± 0.6g/L), in good agreement with the results obtained by an F-kit method. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Vaginal hemodynamic changes during sexual arousal in a rat model by diffuse optical spectroscopy (Conference Presentation)

    Science.gov (United States)

    Jeong, Hyeryun; Seong, Myeongsu; Lee, Hyun-Suk; Park, Kwangsung; Kim, Jae Gwan

    2017-02-01

    Not only men suffer from sexual dysfunction, but the number of women who have sexual dysfunction rises. Therefore, it is necessary to develop an objective diagnostic technique to examine the sexual dysfunction of female patients, who are afflicted with the disorders. For this purpose, we developed a diffuse optical spectroscopy (DOS) probe to measure the change of oxy-, deoxy-, and total hemoglobin concentration along with blood flow from vaginal wall of female rats. A cylindrical stainless steel DOS probe with a diameter of 3 mm was designed for the vaginal wall of rats which consisted of two lasers (785 and 850nm) and two spectrometers with a separation of 2 mm. A thermistor was placed on the top of the probe to measure the temperature change from vaginal wall during experiments. A modified Beer-Lambert's law is utilized to acquire the changes of oxy-, deoxy-, and total hemoglobin, and blood flow information is obtained by diffuse speckle contrast analysis technique. For the experiments, Sprague Dawley ( 400 g) female rats were divided into two groups (control and vaginal dryness model). Vaginal oxygenation, blood flow and temperature were continuously monitored before and after sexual around induced by apomorphine. After the measurement, histologic examination was performed to support the results from DOS probe in the vaginal wall. The hemodynamic information acquired by the DOS probe can be utilized to establish an objective and accurate standard of the female sexual disorders.

  7. Diffusion-weighted imaging in acute bacterial meningitis in infancy

    International Nuclear Information System (INIS)

    Jan, W.; Zimmerman, R.A.; Bilaniuk, L.T.; Hunter, J.V.; Simon, E.M.; Haselgrove, J.

    2003-01-01

    Bacterial meningitis is frequently fatal or leads to severe neurological impairment. Complications such as vasculitis, resulting in infarcts, should be anticipated and dealt with promptly. Our aim was to demonstrate the complications of meningitis by diffusion weighted imaging (DWI) in patients who deteriorated despite therapy. We studied 13 infants between the ages of 1 day and 32 months who presented with symptoms ranging from fever and vomiting to seizures, encephalopathy and coma due to bacterial meningitis, performing MRI, including DWI, 2-5 days after presentation. Multiple infarcts were found on DWI in 12 of the 13, most commonly in the frontal lobes (in 10). Global involvement was seen in four children, three of whom died; the fourth had a very poor outcome. In one case abnormalities on DWI were due to subdural empyemas. We diagnosed vasculitis in three of five patients studied with MRA. We think DWI an important part of an MRI study in infants with meningitis. Small cortical or deep white-matter infarcts due to septic vasculitis can lead to tissue damage not easily recognized on routine imaging and DWI can be used to confirm that extra-axial collections represent empyemas. (orig.)

  8. Diffusion-weighted imaging in acute bacterial meningitis in infancy

    Energy Technology Data Exchange (ETDEWEB)

    Jan, W.; Zimmerman, R.A.; Bilaniuk, L.T.; Hunter, J.V.; Simon, E.M.; Haselgrove, J. [Department of Radiology, Children' s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, PA 19104, Philadelphia (United States)

    2003-09-01

    Bacterial meningitis is frequently fatal or leads to severe neurological impairment. Complications such as vasculitis, resulting in infarcts, should be anticipated and dealt with promptly. Our aim was to demonstrate the complications of meningitis by diffusion weighted imaging (DWI) in patients who deteriorated despite therapy. We studied 13 infants between the ages of 1 day and 32 months who presented with symptoms ranging from fever and vomiting to seizures, encephalopathy and coma due to bacterial meningitis, performing MRI, including DWI, 2-5 days after presentation. Multiple infarcts were found on DWI in 12 of the 13, most commonly in the frontal lobes (in 10). Global involvement was seen in four children, three of whom died; the fourth had a very poor outcome. In one case abnormalities on DWI were due to subdural empyemas. We diagnosed vasculitis in three of five patients studied with MRA. We think DWI an important part of an MRI study in infants with meningitis. Small cortical or deep white-matter infarcts due to septic vasculitis can lead to tissue damage not easily recognized on routine imaging and DWI can be used to confirm that extra-axial collections represent empyemas. (orig.)

  9. Corticospinal tract degeneration and possible pathogenesis in ALS evaluated by MR diffusion tensor imaging

    DEFF Research Database (Denmark)

    Karlsborg, Merete; Rosenbaum, Sverre; Wiegell, Mette R.

    2004-01-01

    BACKGROUND: MR diffusion tensor imaging (DTI) appears to be a powerful method to investigate the neuronal and axonal fibre distribution in the human brain. Changes in diffusion characteristics of water molecules in the white matter can be estimated as the apparent diffusion coefficient (ADC...

  10. Diffusion-weighted MR imaging of non-complicated hepatic cysts: Value of 3T computed diffusion-weighted imaging

    International Nuclear Information System (INIS)

    Nakamura, Yuko; Higaki, Toru; Akiyama, Yuji; Fukumoto, Wataru; Kajiwara, Kenji; Kaichi, Yoko; Honda, Yukiko; Komoto, Daisuke; Tatsugami, Fuminari; Iida, Makoto; Ohmoto, Toshifumi; Date, Shuji; Awai, Kazuo

    2016-01-01

    To investigate the utility of computed 3T diffusion-weighted imaging (c-DWI) for the diagnosis of non-complicated hepatic cysts with a focus on the T2 shine-through effect. In 50 patients with non-complicated hepatic cysts we acquired one set of DWIs (b-value 0 and 1000 s/mm 2 ) at 1.5T, and two sets at 3T (b-value 0 and 1000 s/mm 2 , TE 70 ms; b-value 0 and 600 s/mm 2 , TE 60 ms). We defined the original DWIs acquired with b = 1000 s/mm 2 at 1.5T and 3T as “o-1.5T-1000” and “o-3T-1000”. c-DWIs were calculated with 3T DWI at b-values of 0 and 600 s/mm 2 . c-DWI with b = 1000 and 1500 s/mm 2 were defined as “c-1000” and “c-1500”. Radiologists evaluated the signal intensity (SI) of the cysts using a 3-point score where 1 = not visible, 2 = discernible, and 3 = clearly visible. They calculated the contrast ratio (CR) between the cysts and the surrounding liver parenchyma on each DWIs and recorded the apparent diffusion coefficient (ADC) with a b-value = 0 and 1000 s/mm 2 on 1.5T- and 3T DWIs. Compared with o-1.5T-1000 DWI, the visual scores of all but the c-1500 DWIs were higher (p = 0.07 for c-1500- and p < 0.01 for the other DWIs). The CR at b = 1000 s/mm 2 was higher on o-3T-1000- than on o-1.5T-1000- (p < 0.01) but not higher than on c-1500 DWIs (p = 0.96). The CR at b = 0 s/mm 2 on 3T images with TE 70 ms was higher than on 1.5T images (p < 0.01). The ADC value was higher for 3T- than 1.5T images (p < 0.01). Non-complicated hepatic cysts showed higher SI on o-3T-1000- than o-1.5T-1000 DWIs due to the T2-shine through effect. This high SI was suppressed on c-1500 DWIs

  11. Impact of Gradient Number and Voxel Size on Diffusion Tensor Imaging Tractography for Resective Brain Surgery

    NARCIS (Netherlands)

    Hoefnagels, Friso W. A.; de Witt Hamer, Philip C.; Pouwels, Petra J. W.; Barkhof, Frederik; Vandertop, W. Peter

    2017-01-01

    To explore quantitatively and qualitatively how the number of gradient directions (NGD) and spatial resolution (SR) affect diffusion tensor imaging (DTI) tractography in patients planned for brain tumor surgery, using routine clinical magnetic resonance imaging protocols. Of 67 patients with

  12. Spectroscopie du Furanne et du Thiophene Par Diffusion Inelastique D'electrons

    Science.gov (United States)

    Lotfi, Said

    Nous avons etudie les molecules de furanne ( rm C_4H_4O) et de thiophene (rm C_4H_4O) au moyen de la spectroscopie de diffusion inelastique d'electrons. Pour (rm C_4H_4O), les spectres realises dans differentes conditions d'energie d'impact et d'angle de diffusion contiennent des singularites ou des families de pics correspondant a: (1) des vibrations de l'etat fondamental dans le domaine 0-0.5 eV, (2) des etats triplets ^3 B_1 et ^3 A_1 qui dominent la region 3-5.5 eV, (3) des etats de valences, entre 5 et 10 eV, dont certains son accompagnes de progressions vibrationnelles, soit ~ A _1B_2, ~ B ^1A_1 et ~ C ^1A_1, (4) toujours entre 5 et 10 eV, deux series de Ryhdberg (rm 1a_2to nda_2 et rm 1a_2to npb_2) qui convergent vers la premiere limite d'ionisation de la molecule, avec une progression vibrationnelle associee au mdoe nu_4 pour la seconde, et une troisieme serie (rm 2b_1to nsa_1 ) convergent vers la seconde limite d'ionisation accompagnee de la progression de mode nu _1. Pour rm C_4H_4S, nos spectres presentent les memes etats de vibration et les memes etats triplets que pour rm C_4H _4O. Nous avons releve egalement, dans la region de 5 a 10 eV, des etats de valence ~ A ^1A_1 (ou ~ A ^1B_2), ~ B ^1A_1 (ou ~ B ^1B _2) et ~ C ^1A_1 (ou ~ C ^1B_2). Pour la premiere fois, par la spectroscopie de diffusion inelastique d'electrons, de nombreux pics ont ete identifies et attribues, dans le cadre de ce travail. Il s'agit, notamment, des etats de vibration de l'etat electronique fondamental de ces molecules et egalement de certains etats de Rydberg dans le cas du furanne.

  13. Osteosarcoma subtypes: Magnetic resonance and quantitative diffusion weighted imaging criteria.

    Science.gov (United States)

    Zeitoun, Rania; Shokry, Ahmed M; Ahmed Khaleel, Sahar; Mogahed, Shaimaa M

    2018-03-01

    Osteosarcoma (OS) is a primary bone malignancy, characterized by spindle cells producing osteoid. The objective of this study is to describe the magnetic resonance imaging (MRI) features of different OS subtypes, record their attenuation diffusion coefficient (ADC) values and to point to the relation of their pathologic base and their corresponding ADC value. We performed a retrospective observational lesion-based analysis for 31 pathologically proven osteosarcoma subtypes: osteoblastic (n = 9), fibroblastic (n = 8), chondroblastic (n = 6), para-osteal (n = 3), periosteal (n = 1), telangiectatic (n = 2), small cell (n = 1) and extra-skeletal (n = 1). On conventional images we recorded: bone of origin, epicenter, intra-articular extension, and invasion of articulating bones, skip lesions, distant metastases, pathological fractures, ossified matrix, hemorrhage and necrosis. We measured the mean ADC value for each lesion. Among the included OS lesions, 51.6% originated at the femur, 29% showed intra-articular extension, 16% invaded neighboring bone, 9% were associated with pathological fracture and 25.8% were associated with distant metastases. On MRI, all lesions showed ossified matrix, 35.5% showed hemorrhage and 58% showed necrosis. The mean ADC values for OS lesions ranged from 0.74 × 10 -3  mm 2 /s (recorded for conventional osteoblastic OS) to 1.50 × 10 -3  mm 2 /s (recorded for telangiectatic OS) with an average value of 1.16 ± 0.18 × 10 -3  mm 2 /s. Conventional chondroblastic OS recorded higher values compared to the other two conventional subtypes. Osteosarcoma has different pathologic subtypes which correspondingly vary in their imaging criteria and their ADC values. Copyright © 2018. Production and hosting by Elsevier B.V.

  14. Diffusion weighted imaging and estimation of prognosis using apparent diffusion coefficient measurements in ischemic stroke

    Energy Technology Data Exchange (ETDEWEB)

    Gonen, Korcan Aysun, E-mail: aysunbalc@yahoo.com [Department of Radiology, State Hospital, Eski Cami district, Hastane street, N:1, 59300, Tekirdag (Turkey); Simsek, Mehmet Masum, E-mail: radyoloji@haydapasanumune.gov.tr [Department of Radiology, Haydarpasa Numune Training and Research Hospital, Tibbiye street, Uskudar 34200, Istanbul (Turkey)

    2010-11-15

    Objective: Estimation of the prognosis of infarction by using diffusion weighted imaging (DWI) and quantitative apparent diffusion coefficient (ADC) measurements. Methods: 23 patients having acute stroke symptoms with verified infarction in magnetic resonance imaging (MRI) were included in this study. Their MRI studies were performed between 6 and 12 h after the onset of their symptoms and were repeated on the fifth day. The infarction volumes were calculated by using DWI and the patients were divided into two groups as the ones having an expansion in the infarction area (group 1, n = 16) and the others having no expansion in the infarction area (group 2, n = 7). Quantitative ADC values were estimated. The groups were compared in terms of the ADC values on ADC maps obtained from DWI, performed during the between 6 and 12 h from the onset of the symptoms, referring to the core of the infarction (ADC{sub IC}), ischemic penumbra (ADC{sub P}) and the nonischemic parenchymal tissue (ADC{sub N}). P values < 0.05 were accepted to be statistically significant. Results: During the between 6 and 12 h mean infarction volume calculated by DWI was 23.3 cm{sup 3} for group 1 patients (ranging from 1.1 to 68.6) and this was found to be 40.3 cm{sup 3} (ranging from 1.8 to 91.5) on the fifth day. For the group 2 patients these values were found to be 42.1 cm{sup 3} (ranging from 1 to 94.7) and 41.9 (ranging from 1 to 94.7) for the same intervals respectively. A significant statistical result was failed to be demonstrated between the mean ADC{sub IC} and ADC{sub N} values (p = 0.350 and p = 0.229 respectively). However the comparison of the ADC{sub P} values between the groups was found to be highly significant (p < 0.001). When the differences between the ADC{sub P} and ADC{sub IC} and ADC{sub N} and ADC{sub P} were compared the results proved to be statistically significant (p = 0.038 and p < 0.001 respectively). Conclusions: We believe that ADC results that would be obtained from

  15. Diffusion weighted imaging and estimation of prognosis using apparent diffusion coefficient measurements in ischemic stroke

    International Nuclear Information System (INIS)

    Gonen, Korcan Aysun; Simsek, Mehmet Masum

    2010-01-01

    Objective: Estimation of the prognosis of infarction by using diffusion weighted imaging (DWI) and quantitative apparent diffusion coefficient (ADC) measurements. Methods: 23 patients having acute stroke symptoms with verified infarction in magnetic resonance imaging (MRI) were included in this study. Their MRI studies were performed between 6 and 12 h after the onset of their symptoms and were repeated on the fifth day. The infarction volumes were calculated by using DWI and the patients were divided into two groups as the ones having an expansion in the infarction area (group 1, n = 16) and the others having no expansion in the infarction area (group 2, n = 7). Quantitative ADC values were estimated. The groups were compared in terms of the ADC values on ADC maps obtained from DWI, performed during the between 6 and 12 h from the onset of the symptoms, referring to the core of the infarction (ADC IC ), ischemic penumbra (ADC P ) and the nonischemic parenchymal tissue (ADC N ). P values 3 for group 1 patients (ranging from 1.1 to 68.6) and this was found to be 40.3 cm 3 (ranging from 1.8 to 91.5) on the fifth day. For the group 2 patients these values were found to be 42.1 cm 3 (ranging from 1 to 94.7) and 41.9 (ranging from 1 to 94.7) for the same intervals respectively. A significant statistical result was failed to be demonstrated between the mean ADC IC and ADC N values (p = 0.350 and p = 0.229 respectively). However the comparison of the ADC P values between the groups was found to be highly significant (p P and ADC IC and ADC N and ADC P were compared the results proved to be statistically significant (p = 0.038 and p < 0.001 respectively). Conclusions: We believe that ADC results that would be obtained from the core and the penumbra of the infarction area will be beneficial in the estimation of the infarction prognosis and in the planning of a treatment protocol.

  16. Rocky Mountain spotted fever: 'starry sky' appearance with diffusion-weighted imaging in a child.

    Science.gov (United States)

    Crapp, Seth; Harrar, Dana; Strother, Megan; Wushensky, Curtis; Pruthi, Sumit

    2012-04-01

    We present a case of Rocky Mountain spotted fever encephalitis in a child imaged utilizing diffusion-weighted MRI. Although the imaging and clinical manifestations of this entity have been previously described, a review of the literature did not reveal any such cases reported in children utilizing diffusion-weighted imaging. The imaging findings and clinical history are presented as well as a brief review of this disease.

  17. Love songs, bird brains and diffusion tensor imaging.

    Science.gov (United States)

    De Groof, Geert; Van der Linden, Annemie

    2010-08-01

    The song control system of songbirds displays a remarkable seasonal neuroplasticity in species in which song output also changes seasonally. Thus far, this song control system has been extensively analyzed by histological and electrophysiological methods. However, these approaches do not provide a global view of the brain and/or do not allow repeated measurements, which are necessary to establish causal correlations between alterations in neural substrate and behavior. Research has primarily been focused on the song nuclei themselves, largely neglecting their interconnections and other brain regions involved in seasonally changing behavior. In this review, we introduce and explore the song control system of songbirds as a natural model for brain plasticity. At the same time, we point out the added value of the songbird brain model for in vivo diffusion tensor techniques and its derivatives. A compilation of the diffusion tensor imaging (DTI) data obtained thus far in this system demonstrates the usefulness of this in vivo method for studying brain plasticity. In particular, it is shown to be a perfect tool for long-term studies of morphological and cellular changes of specific brain circuits in different endocrine/photoperiod conditions. The method has been successfully applied to obtain quantitative measurements of seasonal changes of fiber tracts and nuclei from the song control system. In addition, outside the song control system, changes have been discerned in the optic chiasm and in an interhemispheric connection. DTI allows the detection of seasonal changes in a region analogous to the mammalian secondary auditory cortex and in regions of the 'social behavior network', an interconnected group of structures that controls multiple social behaviors, including aggression and courtship. DTI allows the demonstration, for the first time, that the songbird brain in its entirety exhibits an extreme seasonal plasticity which is not merely limited to the song control

  18. Spinal cord diffusion tensor imaging in patients with sensory neuronopathy

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes Casseb, Raphael [University of Campinas - UNICAMP, Department of Neurology, School of Medicine, Campinas, SP (Brazil); University of Campinas - UNICAMP, Neurophysics Group, Department of Cosmic Rays and Chronology, Institute of Physics Gleb Wataghin, Campinas, SP (Brazil); Ribeiro de Paiva, Jean Levi; Teixeira Branco, Lucas Melo; Muro Martinez, Alberto Rolim; Cavalcante Franca, Marcondes Jr. [University of Campinas - UNICAMP, Department of Neurology, School of Medicine, Campinas, SP (Brazil); Reis, Fabiano [University of Campinas - UNICAMP, Department of Radiology, School of Medicine, Campinas, SP (Brazil); Lima-Junior, Jose Carlos de [University of Campinas - UNICAMP, Laboratory of Cell Signaling, Department of Internal Medicine, Campinas, SP (Brazil); Castellano, Gabriela [University of Campinas - UNICAMP, Neurophysics Group, Department of Cosmic Rays and Chronology, Institute of Physics Gleb Wataghin, Campinas, SP (Brazil)

    2016-11-15

    We investigated whether MR diffusion tensor imaging (DTI) analysis of the cervical spinal cord could aid the (differential) diagnosis of sensory neuronopathies, an underdiagnosed group of diseases of the peripheral nervous system. We obtained spinal cord DTI and T2WI at 3 T from 28 patients, 14 diabetic subjects with sensory-motor distal polyneuropathy, and 20 healthy controls. We quantified DTI-based parameters and looked at the hyperintense T2W signal at the spinal cord posterior columns. Fractional anisotropy and mean diffusivity values at C2-C3 and C3-C4 levels were compared between groups. We also compared average fractional anisotropy (mean of values at C2-C3 and C3-C4 levels). A receiver operating characteristic (ROC) curve was used to determine diagnostic accuracy of average fractional anisotropy, and we compared its sensitivity against the hyperintense signal in segregating patients from the other subjects. Mean age and disease duration were 52 ± 10 and 11.4 ± 9.3 years in the patient group. Eighteen subjects had idiopathic disease and 6 dysimmune etiology. Fractional anisotropy at C3-C4 level and average fractional anisotropy were significantly different between patients and healthy controls (p < 0.001 and <0.001) and between patients and diabetic subjects (p = 0.019 and 0.027). Average fractional anisotropy presented an area under the curve of 0.838. Moreover, it had higher sensitivity than visual detection of the hyperintense signal (0.86 vs. 0.54), particularly for patients with short disease duration. DTI-based analysis enables in vivo detection of posterior column damage in sensory neuronopathy patients and is a useful diagnostic test for this condition. It also helps the differential diagnosis between sensory neuronopathy and distal polyneuropathies. (orig.)

  19. Spinal cord diffusion tensor imaging in patients with sensory neuronopathy

    International Nuclear Information System (INIS)

    Fernandes Casseb, Raphael; Ribeiro de Paiva, Jean Levi; Teixeira Branco, Lucas Melo; Muro Martinez, Alberto Rolim; Cavalcante Franca, Marcondes Jr.; Reis, Fabiano; Lima-Junior, Jose Carlos de; Castellano, Gabriela

    2016-01-01

    We investigated whether MR diffusion tensor imaging (DTI) analysis of the cervical spinal cord could aid the (differential) diagnosis of sensory neuronopathies, an underdiagnosed group of diseases of the peripheral nervous system. We obtained spinal cord DTI and T2WI at 3 T from 28 patients, 14 diabetic subjects with sensory-motor distal polyneuropathy, and 20 healthy controls. We quantified DTI-based parameters and looked at the hyperintense T2W signal at the spinal cord posterior columns. Fractional anisotropy and mean diffusivity values at C2-C3 and C3-C4 levels were compared between groups. We also compared average fractional anisotropy (mean of values at C2-C3 and C3-C4 levels). A receiver operating characteristic (ROC) curve was used to determine diagnostic accuracy of average fractional anisotropy, and we compared its sensitivity against the hyperintense signal in segregating patients from the other subjects. Mean age and disease duration were 52 ± 10 and 11.4 ± 9.3 years in the patient group. Eighteen subjects had idiopathic disease and 6 dysimmune etiology. Fractional anisotropy at C3-C4 level and average fractional anisotropy were significantly different between patients and healthy controls (p < 0.001 and <0.001) and between patients and diabetic subjects (p = 0.019 and 0.027). Average fractional anisotropy presented an area under the curve of 0.838. Moreover, it had higher sensitivity than visual detection of the hyperintense signal (0.86 vs. 0.54), particularly for patients with short disease duration. DTI-based analysis enables in vivo detection of posterior column damage in sensory neuronopathy patients and is a useful diagnostic test for this condition. It also helps the differential diagnosis between sensory neuronopathy and distal polyneuropathies. (orig.)

  20. Diffusion tensor imaging detects ventilation-induced brain injury in preterm lambs.

    Directory of Open Access Journals (Sweden)

    Dhafer M Alahmari

    Full Text Available Injurious mechanical ventilation causes white matter (WM injury in preterm infants through inflammatory and haemodynamic pathways. The relative contribution of each of these pathways is not known. We hypothesised that in vivo magnetic resonance imaging (MRI can detect WM brain injury resulting from mechanical ventilation 24 h after preterm delivery. Further we hypothesised that the combination of inflammatory and haemodynamic pathways, induced by umbilical cord occlusion (UCO increases brain injury at 24 h.Fetuses at 124±2 days gestation were exposed, instrumented and either ventilated for 15 min using a high tidal-volume (VT injurious strategy with the umbilical cord intact (INJ; inflammatory pathway only, or occluded (INJ+UCO; inflammatory and haemodynamic pathway. The ventilation groups were compared to lambs that underwent surgery but were not ventilated (Sham, and lambs that did not undergo surgery (unoperated control; Cont. Fetuses were placed back in utero after the 15 min intervention and ewes recovered. Twenty-four hours later, lambs were delivered, placed on a protective ventilation strategy, and underwent MRI of the brain using structural, diffusion tensor imaging (DTI and magnetic resonance spectroscopy (MRS techniques.Absolute MRS concentrations of creatine and choline were significantly decreased in INJ+UCO compared to Cont lambs (P = 0.03, P = 0.009, respectively; no significant differences were detected between the INJ or Sham groups and the Cont group. Axial diffusivities in the internal capsule and frontal WM were lower in INJ and INJ+UCO compared to Cont lambs (P = 0.05, P = 0.04, respectively. Lambs in the INJ and INJ+UCO groups had lower mean diffusivities in the frontal WM compared to Cont group (P = 0.04. DTI colour mapping revealed lower diffusivity in specific WM regions in the Sham, INJ, and INJ+UCO groups compared to the Cont group, but the differences did not reach significance. INJ+UCO lambs more likely to exhibit

  1. Measuring Restriction Sizes Using Diffusion Weighted Magnetic Resonance Imaging: A Review

    Directory of Open Access Journals (Sweden)

    Melanie Martin

    2013-01-01

    Full Text Available This article reviews a new concept in magnetic resonance as applied to cellular and biological systems. Diffusion weighted magnetic resonance imaging can be used to infer information about restriction sizes of samples being measured. The measurements rely on the apparent diffusion coefficient changing with diffusion times as measurements move from restricted to free diffusion regimes. Pulsed gradient spin echo (PGSE measurements are limited in the ability to shorten diffusion times and thus are limited in restriction sizes which can be probed. Oscillating gradient spin echo (OGSE measurements could provide shorter diffusion times so smaller restriction sizes could be probed.

  2. MR chemical shift imaging and spectroscopy of atherosclerotic plaque

    International Nuclear Information System (INIS)

    Vinitski, S.; Consigny, P.M.; Shapiro, M.J.; Janes, N.; Smullens, S.N.; Rifkin, M.D.

    1989-01-01

    The purpose of this study was to develop a technique for in vivo imaging and characterization of atherosclerotic plaque. The authors used a spin-echo technique with a short echo time (TE) of 11 msec. Lipid/water suppression was achieved by means of hybrid chemical shift imaging. Lesions were induced in three rabbits by a combination of balloon denudation of the abdominal aorta and a high-cholesterol diet. Following in vivo imaging of these rabbit aortas and human carotid arteries (1.5 T), the animals were killed or carotid endarterectomy was performed so that the plaques could be excised. The plaques were then analyzed in vitro both histologically and with high-resolution spectroscopy (8.5 T). Use of the short TE improved lesion visualization. The fat/water suppression showed only a small amount of mobile lipids in plaque. Both MR spectroscopic and histologic analysis corroborated these images. The composition of atherosclerotic plaques in both humans and rabbits was demonstrated to be heterogeneous, with predominantly nonmobile lipids. These results suggest that the combination of short TE MR imaging and fat/water suppression can identify plaque and delineate areas containing mobile lipids

  3. Relationship between timed 25-foot walk and diffusion tensor imaging in multiple sclerosis.

    Science.gov (United States)

    Klineova, Sylvia; Farber, Rebecca; Saiote, Catarina; Farrell, Colleen; Delman, Bradley N; Tanenbaum, Lawrence N; Friedman, Joshua; Inglese, Matilde; Lublin, Fred D; Krieger, Stephen

    2016-01-01

    The majority of multiple sclerosis patients experience impaired walking ability, which impacts quality of life. Timed 25-foot walk is commonly used to gauge gait impairment but results can be broadly variable. Objective biological markers that correlate closely with patients' disability are needed. Diffusion tensor imaging, quantifying fiber tract integrity, might provide such information. In this project we analyzed relationships between timed 25-foot walk, conventional and diffusion tensor imaging magnetic resonance imaging markers. A cohort of gait impaired multiple sclerosis patients underwent brain and cervical spinal cord magnetic resonance imaging. Diffusion tensor imaging mean diffusivity and fractional anisotropy were measured on the brain corticospinal tracts and spinal restricted field of vision at C2/3. We analyzed relationships between baseline timed 25-foot walk, conventional and diffusion tensor imaging magnetic resonance imaging markers. Multivariate linear regression analysis showed a statistically significant association between several magnetic resonance imaging and diffusion tensor imaging metrics and timed 25-foot walk: brain mean diffusivity corticospinal tracts (p = 0.004), brain corticospinal tracts axial and radial diffusivity (P = 0.004 and 0.02), grey matter volume (p = 0.05), white matter volume (p = 0.03) and normalized brain volume (P = 0.01). The linear regression model containing mean diffusivity corticospinal tracts and controlled for gait assistance was the best fit model (p = 0.004). Our results suggest an association between diffusion tensor imaging metrics and gait impairment, evidenced by brain mean diffusivity corticospinal tracts and timed 25-foot walk.

  4. Diffusion-weighted MR images and pineoblastoma. Diagnosis and follow-up

    International Nuclear Information System (INIS)

    Gasparetto, Emerson L.; Cruz Junior, L. Celso Hygino; Doring, Thomas M.; Domingues, Romeu C.; Araujo, Bertha; Dantas, Mario Alberto; Chimelli, Leila

    2008-01-01

    Pineoblastomas are uncommon pineal tumors, which demonstrate rapid growing and poor prognosis. We report the case of a 43-year-old man with an enhancing pineal region mass, which showed restriction of the diffusion on diffusion-weighted (DW) MR images. The surgical biopsy defined the diagnosis of pineoblastoma and the therapy was initiated with radiation and chemotherapy. Three months later, the follow-up MR imaging showed areas suggestive of necrosis and the DW images demonstrate no significant areas of restricted diffusion. The differential diagnosis of pineal region masses that could show restriction of diffusion is discussed. (author)

  5. The relationship between functional magnetic resonance imaging activation, diffusion tensor imaging, and training effects.

    Science.gov (United States)

    Farrar, Danielle; Budson, Andrew E

    2017-04-01

    While the relationship between diffusion tensor imaging (DTI) measurements and training effects is explored by Voelker et al. (this issue), a cursory discussion of functional magnetic resonance imaging (fMRI) measurements categorizes increased activation with findings of greater white matter integrity. Evidence of the relationship between fMRI activation and white matter integrity is conflicting, as is the relationship between fMRI activation and training effects. An examination of the changes in fMRI activation in response to training is helpful, but the relationship between DTI and fMRI activation, particularly in the context of white matter changes, must be examined further before general conclusions can be drawn.

  6. Ultrasound elastic tensor imaging: comparison with MR diffusion tensor imaging in the myocardium

    Science.gov (United States)

    Lee, Wei-Ning; Larrat, Benoît; Pernot, Mathieu; Tanter, Mickaël

    2012-08-01

    We have previously proven the feasibility of ultrasound-based shear wave imaging (SWI) to non-invasively characterize myocardial fiber orientation in both in vitro porcine and in vivo ovine hearts. The SWI-estimated results were in good correlation with histology. In this study, we proposed a new and robust fiber angle estimation method through a tensor-based approach for SWI, coined together as elastic tensor imaging (ETI), and compared it with magnetic resonance diffusion tensor imaging (DTI), a current gold standard and extensively reported non-invasive imaging technique for mapping fiber architecture. Fresh porcine (n = 5) and ovine (n = 5) myocardial samples (20 × 20 × 30 mm3) were studied. ETI was firstly performed to generate shear waves and to acquire the wave events at ultrafast frame rate (8000 fps). A 2.8 MHz phased array probe (pitch = 0.28 mm), connected to a prototype ultrasound scanner, was mounted on a customized MRI-compatible rotation device, which allowed both the rotation of the probe from -90° to 90° at 5° increments and co-registration between two imaging modalities. Transmural shear wave speed at all propagation directions realized was firstly estimated. The fiber angles were determined from the shear wave speed map using the least-squares method and eigen decomposition. The test myocardial sample together with the rotation device was then placed inside a 7T MRI scanner. Diffusion was encoded in six directions. A total of 270 diffusion-weighted images (b = 1000 s mm-2, FOV = 30 mm, matrix size = 60 × 64, TR = 6 s, TE = 19 ms, 24 averages) and 45 B0 images were acquired in 14 h 30 min. The fiber structure was analyzed by the fiber-tracking module in software, MedINRIA. The fiber orientation in the overlapped myocardial region which both ETI and DTI accessed was therefore compared, thanks to the co-registered imaging system. Results from all ten samples showed good correlation (r2 = 0.81, p 0.05, unpaired, one-tailed t-test, N = 10). In

  7. Diffuse-reflectance fourier-transform mid-infrared spectroscopy as a method of characterizing changes in soil organic matter

    Science.gov (United States)

    Diffuse-Reflectance Fourier-Transform Mid-Infrared Spectroscopy (MidIR) can identify the presence of important organic functional groups in soil organic matter (SOM). Soils contain myriad organic and inorganic components that absorb in the MidIR so spectral interpretation needs to be validated in or...

  8. Improvement of direct determination of trace nickel in environmental samples by diffuse reflection spectroscopy using chromaticity characteristics.

    Science.gov (United States)

    Ershova, N I; Ivanov, V M

    2000-05-01

    Cellulose and chromaton-N-super as solid supports for direct determination of the immobilized nickel complexes with dimethylglyoxime and benzyldioxime by diffuse reflection spectroscopy were compared. The advantage of chromaton-N-super with use of benzyldioxime is shown. Detection limit is 0.02 microg/mL. The proposed method was applied for the analysis of soil.

  9. Diagnosis of breast cancer using diffuse optical spectroscopy from 500 to 1600 nm: a comparison of classification methods

    NARCIS (Netherlands)

    Nachabe, R.; Evers, D.; Hendriks, B.H.W.; Lucassen, G.W.; Van der Voort, M.; Wesseling, J.; Rutgers, E. J.; Vrancken Peeters, M.J.; Hage, J.A.van der; Oldenbeng, H.S.; Ruers, T.

    2011-01-01

    We report on the use of diffuse optical spectroscopy analysis of breast spectra acquired in the wavelength range from 500 to 1600 nm with a fiber optic probe. A total of 102 ex vivo samples of five different breast tissue types, namely adipose, glandular, fibroadenoma, invasive carcinoma and ductal

  10. Diagnosis of breast cancer using diffuse optical spectroscopy from 500 to 1600 nm: comparison of classification methods

    NARCIS (Netherlands)

    Nachabé, Rami; Evers, Daniel; Evers, Daniel J.; Hendriks, Benno H.W.; Lucassen, Gerald W.; Lucassen, Gerald; van der Voort, Marjolein; Rutgers, Emiel J.; Vrancken Peeters, Marie-Jeanne; van der Hage, Jos A.; Oldenburg, Hester S.; Wesseling, Jelle; Ruers, Theo J.M.

    2011-01-01

    We report on the use of diffuse optical spectroscopy analysis of breast spectra acquired in the wavelength range from 500 to 1600 nm with a fiber optic probe. A total of 102 ex vivo samples of five different breast tissue types, namely adipose, glandular, fibroadenoma, invasive carcinoma, and ductal

  11. Diffusion Tensor Imaging: Application to the Study of the Developing Brain

    Science.gov (United States)

    Cascio, Carissa J.; Gerig, Guido; Piven, Joseph

    2007-01-01

    Objective: To provide an overview of diffusion tensor imaging (DTI) and its application to the study of white matter in the developing brain in both healthy and clinical samples. Method: The development of DTI and its application to brain imaging of white matter tracts is discussed. Forty-eight studies using DTI to examine diffusion properties of…

  12. Functional Near Infrared Spectroscopy: Enabling Routine Functional Brain Imaging.

    Science.gov (United States)

    Yücel, Meryem A; Selb, Juliette J; Huppert, Theodore J; Franceschini, Maria Angela; Boas, David A

    2017-12-01

    Functional Near-Infrared Spectroscopy (fNIRS) maps human brain function by measuring and imaging local changes in hemoglobin concentrations in the brain that arise from the modulation of cerebral blood flow and oxygen metabolism by neural activity. Since its advent over 20 years ago, researchers have exploited and continuously advanced the ability of near infrared light to penetrate through the scalp and skull in order to non-invasively monitor changes in cerebral hemoglobin concentrations that reflect brain activity. We review recent advances in signal processing and hardware that significantly improve the capabilities of fNIRS by reducing the impact of confounding signals to improve statistical robustness of the brain signals and by enhancing the density, spatial coverage, and wearability of measuring devices respectively. We then summarize the application areas that are experiencing rapid growth as fNIRS begins to enable routine functional brain imaging.

  13. Nondestructive millimeter wave imaging and spectroscopy using dielectric focusing probes

    International Nuclear Information System (INIS)

    Hejase, Jose A.; Shane, Steven S.; Park, Kyoung Y.; Chahal, Premjeet

    2014-01-01

    A tool for interrogating objects over a wide band of frequencies with subwavelength resolution at small standoff distances (near field region) in the transmission mode using a single source and detector measurement setup in the millimeter wave band is presented. The design utilizes optics like principles for guiding electromagnetic millimeter waves from large cross-sectional areas to considerably smaller sub-wavelength areas. While plano-convex lenses can be used to focus waves to a fine resolution, they usually require a large stand-off distance thus resulting in alignment and spacing issues. The design procedure and simulation analysis of the focusing probes are presented in this study along with experimental verification of performance and imaging and spectroscopy examples. Nondestructive evaluation will find benefit from such an apparatus including biological tissue imaging, electronic package integrity testing, composite dielectric structure evaluation for defects and microfluidic sensing

  14. Nondestructive millimeter wave imaging and spectroscopy using dielectric focusing probes

    Energy Technology Data Exchange (ETDEWEB)

    Hejase, Jose A.; Shane, Steven S.; Park, Kyoung Y.; Chahal, Premjeet [Terahertz Systems Laboratory (TeSLa) - Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48823 (United States)

    2014-02-18

    A tool for interrogating objects over a wide band of frequencies with subwavelength resolution at small standoff distances (near field region) in the transmission mode using a single source and detector measurement setup in the millimeter wave band is presented. The design utilizes optics like principles for guiding electromagnetic millimeter waves from large cross-sectional areas to considerably smaller sub-wavelength areas. While plano-convex lenses can be used to focus waves to a fine resolution, they usually require a large stand-off distance thus resulting in alignment and spacing issues. The design procedure and simulation analysis of the focusing probes are presented in this study along with experimental verification of performance and imaging and spectroscopy examples. Nondestructive evaluation will find benefit from such an apparatus including biological tissue imaging, electronic package integrity testing, composite dielectric structure evaluation for defects and microfluidic sensing.

  15. Hemorrhagic brain metastases with high signal intensity on diffusion-weighted MR images. A case report

    Energy Technology Data Exchange (ETDEWEB)

    Mori, H.; Abe, O.; Aoki, S.; Masumoto, T.; Yoshikawa, T.; Kunimatsu, A; Hayashi, N.; Ohtomo, K. [Graduate School of Medicine, Univ. of Tokyo (Japan). Dept. of Radiology

    2002-11-01

    Diffusion-weighted MR imaging has been applicable to the differential diagnosis of abscesses and necrotic or cystic brain tumors. However, restricted water diffusion is not necessarily specific for brain abscess. We describe ring-enhancing metastases of lung carcinoma characterized by high signal intensity on diffusion-weighted MR images. The signal pattern probably reflected intralesional hemorrhage. The present report adds to the growing literature regarding the differential diagnosis of ring-enhancing brain lesions.

  16. Diffusion-Weighted Magnetic Resonance Imaging in Rhombencephalitis due to Listeria monocytogenes

    Energy Technology Data Exchange (ETDEWEB)

    Hatipoglu, H.G.; Onbasioglu Gurbuz, M.; Sakman, B.; Yuksel, E. [Dept. of Radiology, Ankara Numune Education and Research Hospital, Ankara (Turkey)

    2007-04-15

    We present diffusion-weighted imaging findings of a case of rhombencephalitis due to Listeria monocytogenes. It is a rare, life-threatening disorder. The diagnosis is difficult by clinical findings only. In this report, we aim to draw attention to the role of conventional and diffusion-weighted magnetic resonance imaging findings. To our knowledge, this is the first case report in the literature with apparent diffusion coefficient values of diseased brain parenchyma.

  17. Diffusion-weighted MR imaging of transplanted kidneys: Preliminary report

    International Nuclear Information System (INIS)

    Wypych-Klunder, Katarzyna; Adamowicz, Andrzej; Lemanowicz, Adam; Szczęsny, Wojciech; Włodarczyk, Zbigniew; Serafin, Zbigniew

    2014-01-01

    An aim of this study was to assess the feasibility of DWI in the early period after kidney transplantation. We also aimed to compare ADC and eADC values in the cortex and medulla of the kidney, to estimate image noise and variability of measurements, and to verify possible relation between selected labolatory results and diffusion parameters in the transplanted kidney. Examinations were performed using a 1.5 T MR unit. DWI (SE/EPI) was performed in the axial plane using b-values of 600 and 1000. ADC and eADC measurements were performed in four regions of interest within the renal cortex and in three regions within the medulla. Relative variability of results and signal-to-noise ratio (SNR) were calculated. The analysis included 15 patients (mean age 52 years). The mean variability of ADC was significantly lower than that of eADC (6.8% vs. 10.8%, respectively; p<0.0001). The mean variability of measurements performed in the cortex was significantly lower than that in the medulla (6.2% vs. 11.5%, respectively; p<0.005). The mean SNR was higher in the measurements using b600 than b1000, it was higher in ADC maps than in the eADC maps, and it was higher in the cortex than in the medulla. ADC and eADC measured at b1000 in the cortex were higher in the group of the patients with eGFR ≤30 ml/min./1.73 m 2 as compared to patients with eGFR >30 ml/min./1.73 m 2 (p<0.05). Diffusion-weighted imaging of transplanted kidneys is technically challenging, especially in patients in the early period after transplantation. From a technical point of view, the best quality parameters offer quality ADC measurement in the renal cortex using b1000. ADC and eADC values in the renal cortex measured at b1000 present a relationship with eGFR

  18. Clinical feasibility of simultaneous multi-slice imaging with blipped-CAIPI for diffusion-weighted imaging and diffusion-tensor imaging of the brain.

    Science.gov (United States)

    Yokota, Hajime; Sakai, Koji; Tazoe, Jun; Goto, Mariko; Imai, Hiroshi; Teramukai, Satoshi; Yamada, Kei

    2017-12-01

    Background Simultaneous multi-slice (SMS) imaging is starting to be used in clinical situation, although evidence of clinical feasibility is scanty. Purpose To prospectively assess the clinical feasibility of SMS diffusion-weighted imaging (DWI) and diffusion-tensor imaging (DTI) with blipped-controlled aliasing in parallel imaging for brain lesions. Material and Methods The institutional review board approved this study. This study included 156 hyperintense lesions on DWI from 32 patients. A slice acceleration factor of 2 was applied for SMS scans, which allowed shortening of the scan time by 41.3%. The signal-to-noise ratio (SNR) was calculated for brain tissue of a selected slice. The contrast-to-noise ratio (CNR), apparent diffusion coefficient (ADC), and fractional anisotropy (FA) were calculated in 36 hyperintense lesions with a diameter of three pixels or more. Visual assessment was performed for all 156 lesions. Tractography of the corticospinal tract of 29 patients was evaluated. The number of tracts and averaged tract length were used for quantitative analysis, and visual assessment was evaluated by grading. Results The SMS scan showed no bias and acceptable 95% limits of agreement compared to conventional scans in SNR, CNR, and ADC on Bland-Altman analyses. Only FA of the lesions was higher in the SMS scan by 9% ( P = 0.016), whereas FA of the surrounding tissues was similar. Quantitative analysis of tractography showed similar values. Visual assessment of DWI hyperintense lesions and tractography also resulted in comparable evaluation. Conclusion SMS imaging was clinically feasible for imaging quality and quantitative values compared with conventional DWI and DTI.

  19. Quantitative measurement of intracellular transport of nanocarriers by spatio-temporal image correlation spectroscopy

    International Nuclear Information System (INIS)

    Coppola, S; Pozzi, D; De Sanctis, S Candeloro; Caracciolo, G; Digman, M A; Gratton, E

    2013-01-01

    Spatio-temporal image correlation spectroscopy (STICS) is a powerful technique for assessing the nature of particle motion in complex systems although it has been rarely used to investigate the intracellular dynamics of nanocarriers so far. Here we introduce a method for characterizing the mode of motion of nanocarriers and for quantifying their transport parameters on different length scales from single-cell to subcellular level. Using this strategy we were able to study the mechanisms responsible for the intracellular transport of DOTAP–DOPC/DNA (DOTAP: 1,2-dioleoyl-3-trimethylammonium-propane; DOPC: dioleoylphosphocholine) and DC-Chol–DOPE/DNA (DC-Chol: 3β-[N-(N,N-dimethylaminoethane)-carbamoyl] cholesterol; DOPE: dioleoylphosphatidylethanolamine) lipoplexes in CHO-K1 (CHO: Chinese hamster ovary) live cells. Measurement of both diffusion coefficients and velocity vectors (magnitude and direction) averaged over regions of the cell revealed the presence of distinct modes of motion. Lipoplexes diffused slowly on the cell surface (diffusion coefficient: D ≈ 0.003 μm 2 s −1 ). In the cytosol, the lipoplexes’ motion was characterized by active transport with average velocity v ≈ 0.03 μm 2 s −1 and random motion. The method permitted us to generate an intracellular transport map showing several regions of concerted motion of lipoplexes. (paper)

  20. Quantitative measurement of intracellular transport of nanocarriers by spatio-temporal image correlation spectroscopy

    Science.gov (United States)

    Coppola, S.; Pozzi, D.; Candeloro De Sanctis, S.; Digman, M. A.; Gratton, E.; Caracciolo, G.

    2013-03-01

    Spatio-temporal image correlation spectroscopy (STICS) is a powerful technique for assessing the nature of particle motion in complex systems although it has been rarely used to investigate the intracellular dynamics of nanocarriers so far. Here we introduce a method for characterizing the mode of motion of nanocarriers and for quantifying their transport parameters on different length scales from single-cell to subcellular level. Using this strategy we were able to study the mechanisms responsible for the intracellular transport of DOTAP-DOPC/DNA (DOTAP: 1,2-dioleoyl-3-trimethylammonium-propane; DOPC: dioleoylphosphocholine) and DC-Chol-DOPE/DNA (DC-Chol: 3β-[N-(N,N-dimethylaminoethane)-carbamoyl] cholesterol; DOPE: dioleoylphosphatidylethanolamine) lipoplexes in CHO-K1 (CHO: Chinese hamster ovary) live cells. Measurement of both diffusion coefficients and velocity vectors (magnitude and direction) averaged over regions of the cell revealed the presence of distinct modes of motion. Lipoplexes diffused slowly on the cell surface (diffusion coefficient: D ≈ 0.003 μm2 s-1). In the cytosol, the lipoplexes’ motion was characterized by active transport with average velocity v ≈ 0.03 μm2 s-1 and random motion. The method permitted us to generate an intracellular transport map showing several regions of concerted motion of lipoplexes.

  1. Improving CT-guided transthoracic biopsy of mediastinal lesions by diffusion-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Marcos Duarte; TyngI, Chiang Cheng; Bitencourt, Almir Galvao Vieira; Gross, Jefferson Luiz; Zurstrassen, Charles Edouard, E-mail: marcosduarte500@gmail.com [AC Camargo Cancer Center, Sao Paulo, SP (Brazil); Hochhegger, Bruno [Universidade Federal de Ciencias da Saude de Porto Alegre (UFCSPA), RS (Brazil). Dept. de Radiologia; Benveniste, Marcelo Felipe Kuperman; Odisio, Bruno Calazans [University of Texas, MD Anderson Cancer Center, Houston, TX (United States); Marchiori, Edson [Universidade Federal do Rio de Janeiro (UFRJ), Petropolis, RJ (Brazil)

    2014-11-15

    Objectives: to evaluate the preliminary results obtained using diffusion-weighted magnetic resonance imaging and the apparent diffusion coefficient for planning computed tomography-guided biopsies of selected mediastinal lesions. Methods: eight patients with mediastinal lesions suspicious for malignancy were referred for computed tomography-guided biopsy. Diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient measurement were performed to assist in biopsy planning with diffusion/computed tomography fused images. We selected mediastinal lesions that could provide discordant diagnoses depending on the biopsy site, including large heterogeneous masses, lesions associated with lung atelectasis or consolidation, lesions involving large mediastinal vessels and lesions for which the results of biopsy using other methods and histopathological examination were divergent from the clinical and radiological suspicion. Results: in all cases, the biopsy needle was successfully directed to areas of higher signal intensity on diffusion weighted sequences and the lowest apparent diffusion coefficient within the lesion (mean, 0.8 [range, 0.6–1.1]610{sup -3} mm{sup 2}/s), suggesting high cellularity. All biopsies provided adequate material for specific histopathological diagnoses of four lymphomas, two sarcomas and two thymoma s. Conclusion: functional imaging tools, such as diffusion-weighted imaging and the apparent diffusion coefficient, are promising for implementation in noninvasive and imaging-guided procedures. However, additional studies are needed to confirm that mediastinal biopsy can be improved with these techniques. (author)

  2. Perfusion and diffusion MR imaging in enhancing malignant cerebral tumors

    International Nuclear Information System (INIS)

    Calli, Cem; Kitis, Omer; Yunten, Nilgun; Yurtseven, Taskin; Islekel, Sertac; Akalin, Taner

    2006-01-01

    Objective: Common contrast-enhancing malignant tumors of the brain are glioblastoma multiforme (GBMs), anaplastic astrocytomas (AAs), metastases, and lymphomas, all of which have sometimes similar conventional MRI findings. Our aim was to evaluate the role of perfusion MR imaging (PWI) and diffusion-weighted imaging (DWI) in the differentiation of these contrast-enhancing malignant cerebral tumors. Materials and methods: Forty-eight patients with contrast-enhancing and histologically proven brain tumors, 14 AAs, 17 GBMs, nine metastases, and eight lymphomas, were included in the study. All patients have undergone routine MR examination where DWI and PWI were performed in the same session. DWI was performed with b values of 0, 500, and 1000 mm 2 /s. Minimum ADC values (ADC min ) of each tumor was later calculated from ADC map images. PWI was applied using dynamic susceptibility contrast technique and maximum relative cerebral blood volume (rCBV max ) was calculated from each tumor, given in ratio with contralateral normal white matter. Comparisons of ADC min and rCBV max values with the histological types of the enhancing tumors were made with a one-way analysis of variance and Bonferroni test. A P value less than 0.05 indicated a statistically significant difference. Results: The ADC min values (mean ± S.D.) in GBMs, AAs, lymphomas, and metastases were 0.79 ± 0.21 (x10 -3 mm 2 /s), 0.75 ± 0.21 (x10 -3 mm 2 /s), 0.51 ± 0.09 (x10 -3 mm 2 /s), and 0.68 ± 0.11 (x10 -3 mm 2 /s), respectively. The difference in ADC min values were statistically significant between lymphomas and GBMs (P max ratio (mean ± S.D.) in GBMs were 6.33 ± 2.03, whereas it was 3.66 ± 1.79 in AAs, 2.33 ± 0.68 in lymphomas, and 4.45 ± 1.87 in metastases. These values were statistically different between GBMs and AAs (P min and rCBV max calculations, may aid routine MR imaging in the differentiation of common cerebral contrast-enhancing malignant tumors

  3. The Advanced X-ray Spectroscopy and Imaging Observatory (AXSIO)

    Science.gov (United States)

    White, Nicholas E.; Bookbinder, Jay; Petre, Robert; Smith, Randall; Ptak, Andrew; Tananbaum, Harvey; Garcia, Michael

    2012-01-01

    Following recommendations from the 2010 "New Worlds, New Horizons" (NWNH) report, the Advanced X-ray Spectroscopy and Imaging Observatory (AXSIO) concept streamlines the International X-ray Observatory (IXO) mission to concentrate on the science objectives that are enabled by high-resolution spectroscopic capabilities. AXSIO will trace orbits close to the event horizon of black holes, measure black hole spin for tens of supermassive black holes (SMBH), use spectroscopy to characterize outflows and the environment of AGN during their peak activity, observe 5MBH out to redshift z=6, map bulk motions and turbulence in galaxy clusters, find the missing baryons in the cosmic web using background quasars, and observe the process of cosmic feedback where black holes and supernovae inject energy on galactic and intergalactic scales. These measurements are enabled by a 0.9 sq m collecting area at 1.25 keV, a micro calorimeter array providing high-resolution spectroscopic imaging and a deployable high efficiency grating spectrometer. AXSIO delivers a 30-fold increase in effective area for high resolution spectroscopy. The key simplifications are guided by recommendations in the NWNH panel report include a reduction in focal length from 20m to 10m, eliminating the extendable optical bench, and a reduction in the instrument complement from six to two, avoiding a movable instrument platform. A focus on spectroscopic science allows the spatial resolution requirement to be relaxed to 10 arc sec (with a 5 arc sec goal). These simplifications decrease the total mission cost to under the $2B cost to NASA recommended by NWNH. AXSIO will be available to the entire astronomical community with observing allocations based on peer-review.

  4. Synergistic efficacy of salicylic acid with a penetration enhancer on human skin monitored by OCT and diffuse reflectance spectroscopy

    Science.gov (United States)

    Zhao, Qingliang; Dai, Cuixia; Fan, Shanhui; Lv, Jing; Nie, Liming

    2016-10-01

    Salicylic acid (SA) has been frequently used as a facial chemical peeling agent (FCPA) in various cosmetics for facial rejuvenation and dermatological treatments in the clinic. However, there is a tradeoff between therapeutic effectiveness and possible adverse effects caused by this agent for cosmetologists. To optimize the cosmetic efficacy with minimal concentration, we proposed a chemical permeation enhancer (CPE) azone to synergistically work with SA on human skin in vivo. The optical properties of human skin after being treated with SA alone and SA combined with azone (SA@azone) were successively investigated by diffuse reflectance spectroscopy (DRS) and optical coherence tomography (OCT). Our results revealed that as the SA concentration increased, the light reflectance decreased and the absorption increased. We also found that SA@azone exhibited a synergistic effect on enhancing light penetration and OCT imaging depth. We demonstrated that the combination of DRS and OCT techniques could be used as a noninvasive, rapid and accurate measurement method to monitor the subtle changes of skin tissue after treatment with FCPA and CPE. The approach will greatly benefit the development of clinical cosmetic surgery, dermatosis diagnosis and therapeutic effect inspection in related biomedical studies.

  5. Deep Into the Fibers! Postmortem Diffusion Tensor Imaging in Forensic Radiology.

    Science.gov (United States)

    Flach, Patricia Mildred; Schroth, Sarah; Schweitzer, Wolf; Ampanozi, Garyfalia; Slotboom, Johannes; Kiefer, Claus; Germerott, Tanja; Thali, Michael J; El-Koussy, Marwan

    2015-09-01

    In traumatic brain injury, diffusion-weighted and diffusion tensor imaging of the brain are essential techniques for determining the pathology sustained and the outcome. Postmortem cross-sectional imaging is an established adjunct to forensic autopsy in death investigation. The purpose of this prospective study was to evaluate postmortem diffusion tensor imaging in forensics for its feasibility, influencing factors and correlation to the cause of death compared with autopsy. Postmortem computed tomography, magnetic resonance imaging, and diffusion tensor imaging with fiber tracking were performed in 10 deceased subjects. The Likert scale grading of colored fractional anisotropy maps was correlated to the body temperature and intracranial pathology to assess the diagnostic feasibility of postmortem diffusion tensor imaging and fiber tracking. Optimal fiber tracking (>15,000 fiber tracts) was achieved with a body temperature at 10°C. Likert scale grading showed no linear correlation (P > 0.7) to fiber tract counts. No statistically significant correlation between total fiber count and postmortem interval could be observed (P = 0.122). Postmortem diffusion tensor imaging and fiber tracking allowed for radiological diagnosis in cases with shearing injuries but was impaired in cases with pneumencephalon and intracerebral mass hemorrhage. Postmortem diffusion tensor imaging with fiber tracking provides an exceptional in situ insight "deep into the fibers" of the brain with diagnostic benefit in traumatic brain injury and axonal injuries in the assessment of the underlying cause of death, considering influencing factors for optimal imaging technique.

  6. Diffusion MR Imaging of Postoperative Bilateral Acute Ischemic Optic Neuropathy

    International Nuclear Information System (INIS)

    Kannan, Anusha; Srinivasan, Sivasubramanian

    2012-01-01

    We read with great interest, the case report on ischemic optic neuropathy (1). We would like to add a few points concerning the blood supply of the optic nerve and the correlation with the development of post-operative ischemic neuropathy. Actually, the perioperative or post-operative vision loss (postoperative ischemic neuropathy) is most likely due to ischemic optic neuropathy. Ischemic optic neuropathy (2) is classified as an anterior ischemic optic neuropathy (AION) and posterior ischemic optic neuropathy (PION). This classification is based on the fact that blood supply (2) to the anterior segment of the optic nerve (part of the optic nerve in the scleral canal and the optic disc) is supplied by short posterior ciliary vessels or anastamotic ring branches around the optic nerve. The posterior part of the optic canal is relatively less perfused, and is supplied by ophthalmic artery and central fibres are perfused by a central retinal artery. So, in the post-operative period, the posterior part of the optic nerve is more vulnerable for ischemia, especially, after major surgeries (3), one of the theories being hypotension or anaemia (2) and resultant decreased perfusion. The onset of PION is slower than the anterior ischemic optic neuropathy. AION on the other hand, is usually spontaneous (idiopathic) or due to arteritis, and is usually sudden in its onset. The reported case is most likely a case of PION. The role of imaging, especially the diffusion weighted magnetic resonance imaging, is very important because the ophthalmoscopic findings in early stages of PION is normal, and it may delay the diagnosis. On the other hand, edema of the disc is usually seen in the early stages of AION.

  7. Diffusion MR Imaging of Postoperative Bilateral Acute Ischemic Optic Neuropathy

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, Anusha; Srinivasan, Sivasubramanian [Khoo Teck Puat Hospital, Singapore (Singapore)

    2012-09-15

    We read with great interest, the case report on ischemic optic neuropathy (1). We would like to add a few points concerning the blood supply of the optic nerve and the correlation with the development of post-operative ischemic neuropathy. Actually, the perioperative or post-operative vision loss (postoperative ischemic neuropathy) is most likely due to ischemic optic neuropathy. Ischemic optic neuropathy (2) is classified as an anterior ischemic optic neuropathy (AION) and posterior ischemic optic neuropathy (PION). This classification is based on the fact that blood supply (2) to the anterior segment of the optic nerve (part of the optic nerve in the scleral canal and the optic disc) is supplied by short posterior ciliary vessels or anastamotic ring branches around the optic nerve. The posterior part of the optic canal is relatively less perfused, and is supplied by ophthalmic artery and central fibres are perfused by a central retinal artery. So, in the post-operative period, the posterior part of the optic nerve is more vulnerable for ischemia, especially, after major surgeries (3), one of the theories being hypotension or anaemia (2) and resultant decreased perfusion. The onset of PION is slower than the anterior ischemic optic neuropathy. AION on the other hand, is usually spontaneous (idiopathic) or due to arteritis, and is usually sudden in its onset. The reported case is most likely a case of PION. The role of imaging, especially the diffusion weighted magnetic resonance imaging, is very important because the ophthalmoscopic findings in early stages of PION is normal, and it may delay the diagnosis. On the other hand, edema of the disc is usually seen in the early stages of AION.

  8. Chronic Effects of Boxing: Diffusion Tensor Imaging and Cognitive Findings.

    Science.gov (United States)

    Wilde, Elisabeth A; Hunter, Jill V; Li, Xiaoqi; Amador, Cristian; Hanten, Gerri; Newsome, Mary R; Wu, Trevor C; McCauley, Stephen R; Vogt, Gregory S; Chu, Zili David; Biekman, Brian; Levin, Harvey S

    2016-04-01

    We used magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) to evaluate the effects of boxing on brain structure and cognition in 10 boxers (8 retired, 2 active; mean age = 45.7 years; standard deviation [SD] = 9.71) and 9 participants (mean age = 43.44; SD = 9.11) in noncombative sports. Evans Index (maximum width of the anterior horns of the lateral ventricles/maximal width of the internal diameter of the skull) was significantly larger in the boxers (F = 4.52; p = 0.050; Cohen's f = 0.531). Word list recall was impaired in the boxers (F(1,14) = 10.70; p = 0.006; f = 0.84), whereas implicit memory measured by faster reaction time (RT) to a repeating sequence of numbers than to a random sequence was preserved (t = 2.52; p boxing had the most consistent, negative correlations with FA, ranging from -0.65 for the right ventral striatum to -0.92 for the right cerebral peduncle. Years of boxing was negatively related to the number of words consistently recalled over trials (r = -0.74; p = 0.02), delayed recall (r = -0.83; p = 0.003), and serial RT (r = 0.66; p = 0.05). We conclude that microstructural integrity of white matter tracts is related to declarative memory and response speed in boxers and to the extent of boxing exposure. Implications for chronic traumatic encephalopathy are discussed.

  9. Some applications of nonlinear diffusion to processing of dynamic evolution images

    International Nuclear Information System (INIS)

    Goltsov, Alexey N.; Nikishov, Sergey A.

    1997-01-01

    Model nonlinear diffusion equation with the most simple Landau-Ginzburg free energy functional was applied to locate boundaries between meaningful regions of low-level images. The method is oriented to processing images of objects that are a result of dynamic evolution: images of different organs and tissues obtained by radiography and NMR methods, electron microscope images of morphogenesis fields, etc. In the methods developed by us, parameters of the nonlinear diffusion model are chosen on the basis of the preliminary treatment of the images. The parameters of the Landau-Ginzburg free energy functional are extracted from the structure factor of the images. Owing to such a choice of the model parameters, the image to be processed is located in the vicinity of the steady-state of the diffusion equation. The suggested method allows one to separate distinct structures having specific space characteristics from the whole image. The method was applied to processing X-ray images of the lung

  10. MR imaging of skeletal muscle injury in rabbit : comparison between diffusion and T2-weighted MR images

    International Nuclear Information System (INIS)

    Kim, Ki Jun; Lee, Sung Yong; Lee, Jae Hee; Kwon Oh Han; Lee, Jae Mun; Lim, Yeon Soo

    2000-01-01

    The purpose of this study was to apply the diffusion-weighted MR imaging technique to the early detection of skeletal muscle injury and to evaluate the usefulness of this imaging sequence. Thirty rabbits, divided into two groups, were included in this study . Skeletal muscle injury was experimentally induced in the right thigh muscles of each rabbit by clamping with a hemostat for one minute. Four-stage clamping was applied to the rabbits in group I, but for group II there was only one stage. Diffusion and T2-weighted MR images were obtained using a 1.5T MR unit. Serial 5-and 30-minute, and 2-, 24-, and 48- hour delayed images were obtained after injury. The initial time of signal intensity change was recorded and the signal intensities of the injured sites and corresponding normal sites were measured and compared. On 5-minute delayed images in group I, diffusion-weighted MR images showed signal intensity changes in injured muscle in all 15 cases, but on T2-weighted images, change was not detected in three cases. In group II, 5-minute delayed T2-weighted images failed to depict the lesion in six cases, but on diffusion-weighted images, all lesions were detected. In addition, one lesion was not detected on 30-minute delayed T2-weighted images. In group II, the sensitivity of lesion detection was significantly higher on diffusion-weighted than on T2-weighted images (p=3D0.0169). Diffusion-weighted MR imaging was shown to be more sensitive than T2-weighted imaging for the detection of signal intensity changes immediately after artificial injury, especially when this was of a lesser degree. These results suggest that diffusion-weighted MR imaging may be useful for the detection of early stage skeletal muscle injury. (author)

  11. Diffusion-weighted MR imaging of the abdomen with pulse triggering

    International Nuclear Information System (INIS)

    Muertz, P.; Pauleit, D.; Traeber, F.; Kreft, B.P.; Schild, H.H.

    2000-01-01

    Purpose: The aim of this work was to reduce the influence of motion on diffusion-weighted MR images of the abdomen by pulse triggering of single-shot sequences. Methods: Five healthy volunteers were examined both without and with finger pulse-triggering of a diffusion-weighted single-shot echo planar MR imaging sequence at 1.5 T. Series of diffusion-weighted images were acquired at different phases of the cardiac cycle by varying the time delay between finger pulse and sequence acquisition. The measurements were repeated three times. The diffusion weighted images were analysed by measuring the signal intensities and by determining the ADC values within the spleen, kidney and liver. Results: The magnitude of motion artifacts on diffusion weighted images shows a strong dependence on the trigger delay. The optimum trigger delay is found to be between 500 and 600 ms. For these values the abdominal organs appear homogeneous on all diffusion weighted images and the strongest signal intensities are detected. At optimum triggering the accuracy of the apparent diffusion coefficients is up to 10 times better than without triggering. Moreover, the standard deviation of the repeated measurements is smaller than 12% for all volunteers and for all organs. Without triggering the standard deviation is larger by a factor of 4 on average. Conclusion: Pulse triggering of single-shot sequences leads to significant reduction of motion related artifacts on diffusion weighted images of the abdomen and provides more accurate and reproducible ADC values. (orig.) [de

  12. Mapping Fire Severity Using Imaging Spectroscopy and Kernel Based Image Analysis

    Science.gov (United States)

    Prasad, S.; Cui, M.; Zhang, Y.; Veraverbeke, S.

    2014-12-01

    Improved spatial representation of within-burn heterogeneity after wildfires is paramount to effective land management decisions and more accurate fire emissions estimates. In this work, we demonstrate feasibility and efficacy of airborne imaging spectroscopy (hyperspectral imagery) for quantifying wildfire burn severity, using kernel based image analysis techniques. Two different airborne hyperspectral datasets, acquired over the 2011 Canyon and 2013 Rim fire in California using the Airborne Visible InfraRed Imaging Spectrometer (AVIRIS) sensor, were used in this study. The Rim Fire, covering parts of the Yosemite National Park started on August 17, 2013, and was the third largest fire in California's history. Canyon Fire occurred in the Tehachapi mountains, and started on September 4, 2011. In addition to post-fire data for both fires, half of the Rim fire was also covered with pre-fire images. Fire severity was measured in the field using Geo Composite Burn Index (GeoCBI). The field data was utilized to train and validate our models, wherein the trained models, in conjunction with imaging spectroscopy data were used for GeoCBI estimation wide geographical regions. This work presents an approach for using remotely sensed imagery combined with GeoCBI field data to map fire scars based on a non-linear (kernel based) epsilon-Support Vector Regression (e-SVR), which was used to learn the relationship between spectra and GeoCBI in a kernel-induced feature space. Classification of healthy vegetation versus fire-affected areas based on morphological multi-attribute profiles was also studied. The availability of pre- and post-fire imaging spectroscopy data over the Rim Fire provided a unique opportunity to evaluate the performance of bi-temporal imaging spectroscopy for assessing post-fire effects. This type of data is currently constrained because of limited airborne acquisitions before a fire, but will become widespread with future spaceborne sensors such as those on

  13. Classification of Error-Diffused Halftone Images Based on Spectral Regression Kernel Discriminant Analysis

    Directory of Open Access Journals (Sweden)

    Zhigao Zeng

    2016-01-01

    Full Text Available This paper proposes a novel algorithm to solve the challenging problem of classifying error-diffused halftone images. We firstly design the class feature matrices, after extracting the image patches according to their statistics characteristics, to classify the error-diffused halftone images. Then, the spectral regression kernel discriminant analysis is used for feature dimension reduction. The error-diffused halftone images are finally classified using an idea similar to the nearest centroids classifier. As demonstrated by the experimental results, our method is fast and can achieve a high classification accuracy rate with an added benefit of robustness in tackling noise.

  14. Multivariate statistical analysis for x-ray photoelectron spectroscopy spectral imaging: Effect of image acquisition time

    International Nuclear Information System (INIS)

    Peebles, D.E.; Ohlhausen, J.A.; Kotula, P.G.; Hutton, S.; Blomfield, C.

    2004-01-01

    The acquisition of spectral images for x-ray photoelectron spectroscopy (XPS) is a relatively new approach, although it has been used with other analytical spectroscopy tools for some time. This technique provides full spectral information at every pixel of an image, in order to provide a complete chemical mapping of the imaged surface area. Multivariate statistical analysis techniques applied to the spectral image data allow the determination of chemical component species, and their distribution and concentrations, with minimal data acquisition and processing times. Some of these statistical techniques have proven to be very robust and efficient methods for deriving physically realistic chemical components without input by the user other than the spectral matrix itself. The benefits of multivariate analysis of the spectral image data include significantly improved signal to noise, improved image contrast and intensity uniformity, and improved spatial resolution - which are achieved due to the effective statistical aggregation of the large number of often noisy data points in the image. This work demonstrates the improvements in chemical component determination and contrast, signal-to-noise level, and spatial resolution that can be obtained by the application of multivariate statistical analysis to XPS spectral images

  15. a Study of the Concentration Dependence of Macromolecular Diffusion Using Photon Correlation Spectroscopy.

    Science.gov (United States)

    Marlowe, Robert Lloyd

    The dynamic light scattering technique of photon correlation spectroscopy has been used to investigate the dependence of the mutual diffusion coefficient of a macromolecular system upon concentration. The first part of the research was devoted to the design and construction of a single-clipping autocorrelator based on newly-developed integrated circuits. The resulting 128 channel instrument can perform real time autocorrelation for sample time intervals >(, )10 (mu)s, and batch processed autocorrelation for intervals down to 3 (mu)s. An improved design for a newer, all-digital autocorrelator is given. Homodyne light scattering experiments were then undertaken on monodisperse solutions of polystyrene spheres. The single-mode TEM(,oo) beam of an argon-ion laser ((lamda) = 5145 (ANGSTROM)) was used as the light source; all solutions were studied at room temperature. The scattering angle was varied from 30(DEGREES) to 110(DEGREES). Excellent agreement with the manufacturer's specification for the particle size was obtained from the photon correlation studies. Finally, aqueous solutions of the globular protein ovalbumin, ranging in concentration from 18.9 to 244.3 mg/ml, were illuminated under the same conditions of temperature and wavelength as before; the homodyne scattered light was detected at a fixed scattering angle of 30(DEGREES). The single-clipped photocount autocorrelation function was analyzed using the homodyne exponential integral method of Meneely et al. The resulting diffusion coefficients showed a general linear dependence upon concentration, as predicted by the generalized Stokes-Einstein equation. However, a clear peak in the data was evident at c (TURNEQ) 100 mg/ml, which could not be explained on the basis of a non -interacting particle theory. A semi-quantitative approach based on the Debye-Huckel theory of electrostatic interactions is suggested as the probable cause for the peak's rise, and an excluded volume effect for its decline.

  16. Diffusing-wave spectroscopy in a standard dynamic light scattering setup

    Science.gov (United States)

    Fahimi, Zahra; Aangenendt, Frank J.; Voudouris, Panayiotis; Mattsson, Johan; Wyss, Hans M.

    2017-12-01

    Diffusing-wave spectroscopy (DWS) extends dynamic light scattering measurements to samples with strong multiple scattering. DWS treats the transport of photons through turbid samples as a diffusion process, thereby making it possible to extract the dynamics of scatterers from measured correlation functions. The analysis of DWS data requires knowledge of the path length distribution of photons traveling through the sample. While for flat sample cells this path length distribution can be readily calculated and expressed in analytical form; no such expression is available for cylindrical sample cells. DWS measurements have therefore typically relied on dedicated setups that use flat sample cells. Here we show how DWS measurements, in particular DWS-based microrheology measurements, can be performed in standard dynamic light scattering setups that use cylindrical sample cells. To do so we perform simple random-walk simulations that yield numerical predictions of the path length distribution as a function of both the transport mean free path and the detection angle. This information is used in experiments to extract the mean-square displacement of tracer particles in the material, as well as the corresponding frequency-dependent viscoelastic response. An important advantage of our approach is that by performing measurements at different detection angles, the average path length through the sample can be varied. For measurements performed on a single sample cell, this gives access to a wider range of length and time scales than obtained in a conventional DWS setup. Such angle-dependent measurements also offer an important consistency check, as for all detection angles the DWS analysis should yield the same tracer dynamics, even though the respective path length distributions are very different. We validate our approach by performing measurements both on aqueous suspensions of tracer particles and on solidlike gelatin samples, for which we find our DWS-based microrheology

  17. Monitoring longitudinal changes in irradiated head and neck cancer xenografts using diffuse reflectance spectroscopy

    Science.gov (United States)

    Vishwanath, Karthik; Jiang, Shudong; Gunn, Jason R.; Marra, Kayla; Andreozzi, Jacqueline M.; Pogue, Brian W.

    2016-02-01

    Radiation therapy is often used as the preferred clinical treatment for control of localized head and neck cancer. However, during the course of treatment (6-8 weeks), feedback about functional and/or physiological changes within impacted tissue are not obtained, given the onerous financial and/or logistical burdens of scheduling MRI, PET or CT scans. Diffuse optical sensing is well suited to address this problem since the instrumentation can be made low-cost and portable while still being able to non-invasively provide information about vascular oxygenation in vivo. Here we report results from studies that employed an optical fiber-based portable diffuse reflectance spectroscopy (DRS) system to longitudinally monitor changes in tumor vasculature within two head and neck cancer cell lines (SCC-15 and FaDu) xenografted in the flanks of nude mice, in two separate experiments. Once the tumor volumes were 100mm3, 67% of animals received localized (electron beam) radiation therapy in five fractions (8Gy/day, for 5 days) while 33% of the animals served as controls. DRS measurements were obtained from each animal on each day of treatment and then for two weeks post-treatment. Reflectance spectra were parametrized to extract total hemoglobin concentration and blood oxygen-saturation and the resulting time-trends of optical parameters appear to be dissimilar for the two cell-lines. These findings are also compared to previous animal experiments (using the FaDu line) that were irradiated using a photon beam radiotherapy protocol. These results and implications for the use of fiber-based DRS measurements made at local (irradiated) tumor site as a basis for identifying early radiotherapy-response are presented and discussed.

  18. Simultaneous estimation of transcutaneous bilirubin, hemoglobin, and melanin based on diffuse reflectance spectroscopy

    Science.gov (United States)

    Nishidate, Izumi; Abdul, Wares MD.; Ohtsu, Mizuki; Nakano, Kazuya; Haneishi, Hideaki

    2018-02-01

    We propose a method to estimate transcutaneous bilirubin, hemoglobin, and melanin based on the diffuse reflectance spectroscopy. In the proposed method, the Monte Carlo simulation-based multiple regression analysis for an absorbance spectrum in the visible wavelength region (460-590 nm) is used to specify the concentrations of bilirubin (Cbil), oxygenated hemoglobin (Coh), deoxygenated hemoglobin (Cdh), and melanin (Cm). Using the absorbance spectrum calculated from the measured diffuse reflectance spectrum as a response variable and the extinction coefficients of bilirubin, oxygenated hemoglobin, deoxygenated hemoglobin, and melanin, as predictor variables, multiple regression analysis provides regression coefficients. Concentrations of bilirubin, oxygenated hemoglobin, deoxygenated hemoglobin, and melanin, are then determined from the regression coefficients using conversion vectors that are numerically deduced in advance by the Monte Carlo simulations for light transport in skin. Total hemoglobin concentration (Cth) and tissue oxygen saturation (StO2) are simply calculated from the oxygenated hemoglobin and deoxygenated hemoglobin. In vivo animal experiments with bile duct ligation in rats demonstrated that the estimated Cbil is increased after ligation of bile duct and reaches to around 20 mg/dl at 72 h after the onset of the ligation, which corresponds to the reference value of Cbil measured by a commercially available transcutaneous bilirubin meter. We also performed in vivo experiments with rats while varying the fraction of inspired oxygen (FiO2). Coh and Cdh decreased and increased, respectively, as FiO2 decreased. Consequently, StO2 was dramatically decreased. The results in this study indicate potential of the method for simultaneous evaluation of multiple chromophores in skin tissue.

  19. The imaging diagnosis of diffuse brain swelling due to severe brain trauma

    International Nuclear Information System (INIS)

    Shen Jianqiang; Hu Jiawang

    2008-01-01

    Objective: To discuss the clinical and pathological characteristics and the imaging types of the diffuse brain swelling due to severe brain trauma. Methods: The clinical data and CT and MR images on 48 cases with diffuse brain swelling due to severe brain trauma were analyzed. Results: Among these 48 cases of the diffuse brain swelling due to severe brain trauma, 33 cases were complicated with brain contusions (including 12 cases brain diffuse axonal injury, 1 case infarct of the right basal ganglion), 31 cases were complicated with hematoma (epidural, subdural or intracerebral), 27 cases were complicated with skull base fracture, and 10 cases were complicated with subarachnoid hematoma. The CT and MR imaging of the diffuse brain swelling included as followed: (1) Symmetrically diffuse brain swelling in both cerebral hemispheres with cerebral ventricles decreased or disappeared, without median line shift. (2)Diffuse brain swelling in one side cerebral hemisphere with cerebral ventricles decreased or disappeared at same side, and median line shift to other side. (3) Subarachnoid hematoma or little subcortex intracerebral hematoma were complicated. (4) The CT value of the cerebral could be equal, lower or higher comparing with normal. Conclusion: The pathological reason of diffuse brain swelling was the brain vessel expanding resulting from hypothalamus and brainstem injured in severe brain trauma. There were four CT and MR imaging findings in diffuse brain swelling. The diffuse brain swelling without hematoma may be caused by ischemical reperfusion injury. (authors)

  20. Prebiopsy magnetic resonance spectroscopy and imaging in the diagnosis of prostate cancer

    International Nuclear Information System (INIS)

    Kumar, V.; Jagannathan, N.R.; Thulkar, S.; Kumar, R.

    2012-01-01

    Existing screening investigations for the diagnosis of early prostate cancer lack specificity, resulting in a high negative biopsy rate. There is increasing interest in the use of various magnetic resonance methods for improving the yield of transrectal ultrasound-guided biopsies of the prostate in men suspected to have prostate cancer. We review the existing status of such investigations. A literature search was carried out using the Pubmed database to identify articles related to magnetic resonance methods for diagnosing prostate cancer. References from these articles were also extracted and reviewed. Recent studies have focused on prebiopsy magnetic resonance investigations using conventional magnetic resonance imaging, dynamic contrast enhanced magnetic resonance imaging, diffusion weighted magnetic resonance imaging, magnetization transfer imaging and magnetic resonance spectroscopy of the prostate. This marks a shift from the earlier strategy of carrying out postbiopsy magnetic resonance investigations. Prebiopsy magnetic resonance investigations has been useful in identifying patients who are more likely to have a biopsy positive for malignancy. Prebiopsy magnetic resonance investigations has a potential role in increasing specificity of screening for early prostate cancer. It has a role in the targeting of biopsy sites, avoiding unnecessary biopsies and predicting the outcome of biopsies. (author)

  1. Mapping Asphaltic Roads’ Skid Resistance Using Imaging Spectroscopy

    Directory of Open Access Journals (Sweden)

    Nimrod Carmon

    2018-03-01

    Full Text Available The purpose of this study is to evaluate a realistic feasibility of using hyperspectral remote sensing (also termed imaging spectroscopy airborne data for mapping asphaltic roads’ transportation safety. This is done by quantifying the road-tire friction, an attribute responsible for vehicle control and emergency stopping. We engaged in a real-life operational scenario, where the roads’ friction was modeled against the reflectance information extracted directly from the image. The asphalt pavement’s dynamic friction coefficient was measured by a standardized technique using a Dynatest 6875H (Dynatest Consulting Inc., Westland, MI, USA Friction Measuring System, which uses the common test-wheel retardation method. The hyperspectral data was acquired by the SPECIM AisaFenix 1K (Specim, Spectral Imaging Ltd., Oulu, Finland airborne system, covering the entire optical range (350–2500 nm, over a selected study site, with roads characterized by different aging conditions. The spectral radiance data was processed to provide apparent surface reflectance using ground calibration targets and the ACORN-6 atmospheric correction package. Our final dataset was comprised of 1370 clean asphalt pixels coupled with geo-rectified in situ friction measurement points. We developed a partial least squares regression model using PARACUDA-II spectral data mining engine, which uses an automated outlier detection procedure and dual validation routines—a full cross-validation and an iterative internal validation based on a Latin Hypercube sampling algorithm. Our results show prediction capabilities of R2 = 0.632 for full cross-validation and R2 = 0.702 for the best available model in internal validation, both with significant results (p < 0.0001. Using spectral assignment analysis, we located the spectral bands with the highest weight in the model and discussed their possible physical and chemical assignments. The derived model was applied back on the

  2. Diffuse reflectance spectroscopy as a tool for real-time tissue assessment during colorectal cancer surgery

    Science.gov (United States)

    Baltussen, Elisabeth J. M.; Snaebjornsson, Petur; de Koning, Susan G. Brouwer; Sterenborg, Henricus J. C. M.; Aalbers, Arend G. J.; Kok, Niels; Beets, Geerard L.; Hendriks, Benno H. W.; Kuhlmann, Koert F. D.; Ruers, Theo J. M.

    2017-10-01

    Colorectal surgery is the standard treatment for patients with colorectal cancer. To overcome two of the main challenges, the circumferential resection margin and postoperative complications, real-time tissue assessment could be of great benefit during surgery. In this ex vivo study, diffuse reflectance spectroscopy (DRS) was used to differentiate tumor tissue from healthy surrounding tissues in patients with colorectal neoplasia. DRS spectra were obtained from tumor tissue, healthy colon, or rectal wall and fat tissue, for every patient. Data were randomly divided into training (80%) and test (20%) sets. After spectral band selection, the spectra were classified using a quadratic classifier and a linear support vector machine. Of the 38 included patients, 36 had colorectal cancer and 2 had an adenoma. When the classifiers were applied to the test set, colorectal cancer could be discriminated from healthy tissue with an overall accuracy of 0.95 (±0.03). This study demonstrates the possibility to separate colorectal cancer from healthy surrounding tissue by applying DRS. High classification accuracies were obtained both in homogeneous and inhomogeneous tissues. This is a fundamental step toward the development of a tool for real-time in vivo tissue assessment during colorectal surgery.

  3. Quantitative skin color measurements in acanthosis nigricans patients: colorimetry and diffuse reflectance spectroscopy.

    Science.gov (United States)

    Pattamadilok, Bensachee; Devpura, Suneetha; Syed, Zain U; Agbai, Oma N; Vemulapalli, Pranita; Henderson, Marsha; Rehse, Steven J; Mahmoud, Bassel H; Lim, Henry W; Naik, Ratna; Hamzavi, Iltefat H

    2012-08-01

    Tristimulus colorimetry and diffuse reflectance spectroscopy (DRS) are white-light skin reflectance techniques used to measure the intensity of skin pigmentation. The tristimulus colorimeter is an instrument that measures a perceived color and the DRS instrument measures biological chromophores of the skin, including oxy- and deoxyhemoglobin, melanin and scattering. Data gathered from these tools can be used to understand morphological changes induced in skin chromophores due to conditions of the skin or their treatments. The purpose of this study was to evaluate the use of these two instruments in color measurements of acanthosis nigricans (AN) lesions. Eight patients with hyperinsulinemia and clinically diagnosable AN were seen monthly. Skin pigmentation was measured at three sites: the inner forearm, the medial aspect of the posterior neck, and anterior neck unaffected by AN. Of the three, measured tristimulus L*a*b* color parameters, the luminosity parameter L* was found to most reliably distinguish lesion from normally pigmented skin. The DRS instrument was able to characterize a lesion on the basis of the calculated melanin concentration, though melanin is a weak indicator of skin change and not a reliable measure to be used independently. Calculated oxyhemoglobin and deoxyhemoglobin concentrations were not found to be reliable indicators of AN. Tristimulus colorimetry may provide reliable methods for respectively quantifying and characterizing the objective color change in AN, while DRS may be useful in characterizing changes in skin melanin content associated with this skin condition. © 2012 John Wiley & Sons A/S.

  4. Non-invasive tissue temperature measurements based on quantitative diffuse optical spectroscopy (DOS) of water

    Energy Technology Data Exchange (ETDEWEB)

    Chung, S H [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Cerussi, A E; Tromberg, B J [Beckman Laser Institute and Medical Clinic, University of California, Irvine, 1002 Health Sciences Road, Irvine 92612, CA (United States); Merritt, S I [Masimo Corporation, 40 Parker, Irvine, CA 92618 (United States); Ruth, J, E-mail: bjtrombe@uci.ed [Department of Bioengineering, University of Pennsylvania, 210 S. 33rd Street, Room 240, Skirkanich Hall, Philadelphia, PA 19104 (United States)

    2010-07-07

    We describe the development of a non-invasive method for quantitative tissue temperature measurements using Broadband diffuse optical spectroscopy (DOS). Our approach is based on well-characterized opposing shifts in near-infrared (NIR) water absorption spectra that appear with temperature and macromolecular binding state. Unlike conventional reflectance methods, DOS is used to generate scattering-corrected tissue water absorption spectra. This allows us to separate the macromolecular bound water contribution from the thermally induced spectral shift using the temperature isosbestic point at 996 nm. The method was validated in intralipid tissue phantoms by correlating DOS with thermistor measurements (R = 0.96) with a difference of 1.1 {+-} 0.91 {sup 0}C over a range of 28-48 {sup 0}C. Once validated, thermal and hemodynamic (i.e. oxy- and deoxy-hemoglobin concentration) changes were measured simultaneously and continuously in human subjects (forearm) during mild cold stress. DOS-measured arm temperatures were consistent with previously reported invasive deep tissue temperature studies. These results suggest that DOS can be used for non-invasive, co-registered measurements of absolute temperature and hemoglobin parameters in thick tissues, a potentially important approach for optimizing thermal diagnostics and therapeutics.

  5. Impact of one-layer assumption on diffuse reflectance spectroscopy of skin

    Science.gov (United States)

    Hennessy, Ricky; Markey, Mia K.; Tunnell, James W.

    2015-02-01

    Diffuse reflectance spectroscopy (DRS) can be used to noninvasively measure skin properties. To extract skin properties from DRS spectra, you need a model that relates the reflectance to the tissue properties. Most models are based on the assumption that skin is homogenous. In reality, skin is composed of multiple layers, and the homogeneity assumption can lead to errors. In this study, we analyze the errors caused by the homogeneity assumption. This is accomplished by creating realistic skin spectra using a computational model, then extracting properties from those spectra using a one-layer model. The extracted parameters are then compared to the parameters used to create the modeled spectra. We used a wavelength range of 400 to 750 nm and a source detector separation of 250 μm. Our results show that use of a one-layer skin model causes underestimation of hemoglobin concentration [Hb] and melanin concentration [mel]. Additionally, the magnitude of the error is dependent on epidermal thickness. The one-layer assumption also causes [Hb] and [mel] to be correlated. Oxygen saturation is overestimated when it is below 50% and underestimated when it is above 50%. We also found that the vessel radius factor used to account for pigment packaging is correlated with epidermal thickness.

  6. Diffuse Reflectance Spectroscopy: Getting the Capillary Refill Test Under One's Thumb.

    Science.gov (United States)

    Henricson, Joakim; Toll John, Rani; Anderson, Chris D; Björk Wilhelms, Daniel

    2017-12-02

    The capillary refill test was introduced in 1947 to help estimate circulatory status in critically ill patients. Guidelines commonly state that refill should occur within 2 s after releasing 5 s of firm pressure (e.g., by the physician's finger) in the normal healthy supine patient. A slower refill time indicates poor skin perfusion, which can be caused by conditions including sepsis, blood loss, hypoperfusion, and hypothermia. Since its introduction, the clinical usefulness of the test has been debated. Advocates point out its feasibility and simplicity and claim that it can indicate changes in vascular status earlier than changes in vital signs such as heart rate. Critics, on the other hand, stress that the lack of standardization in how the test is performed and the highly subjective nature of the naked eye assessment, as well as the test's susceptibility to ambient factors, markedly lowers the clinical value. The aim of the present work is to describe in detail the course of the refill event and to suggest potentially more objective and exact endpoint values for the capillary refill test using diffuse polarization spectroscopy.

  7. Decreased microvascular cerebral blood flow assessed by diffuse correlation spectroscopy after repetitive concussions in mice.

    Science.gov (United States)

    Buckley, Erin M; Miller, Benjamin F; Golinski, Julianne M; Sadeghian, Homa; McAllister, Lauren M; Vangel, Mark; Ayata, Cenk; Meehan, William P; Franceschini, Maria Angela; Whalen, Michael J

    2015-12-01

    Repetitive concussions are associated with long-term cognitive dysfunction that can be attenuated by increasing the time intervals between concussions; however, biomarkers of the safest rest interval between injuries remain undefined. We hypothesize that deranged cerebral blood flow (CBF) is a candidate biomarker for vulnerability to repetitive concussions. Using a mouse model of human concussion, we examined the effect of single and repetitive concussions on cognition and on an index of CBF (CBFi) measured with diffuse correlation spectroscopy. After a single mild concussion, CBFi was reduced by 35±4% at 4 hours (Pconcussions spaced 1 day apart, CBFi was also reduced from preinjury levels 4 hours after each concussion but had returned to preinjury levels by 72 hours after the final concussion. Interestingly, in this repetitive concussion model, lower CBFi values measured both preinjury and 4 hours after the third concussion were associated with worse performance on the Morris water maze assessed 72 hours after the final concussion. We conclude that low CBFi measured either before or early on in the evolution of injury caused by repetitive concussions could be a useful predictor of cognitive outcome.

  8. Diffusion-weighted MR imaging in biopsy-proven Creutzfeldt-Jakob disease

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyo Cheol; Chang, Kee Hyun; Song In Chan; Lee, Sang Hyun; Kwon, Bae Ju; Han, Moon Hee; Kim, Sang Yun [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2001-12-01

    To compare conventional and diffusion-weighted MR imaging in terms of their depiction of the abnormalities occurring in Creutzfeldt-Jakob disease. We retrospectively analyzed the findings of conventional (T2-weighted and fluid-attenuated inversion recovery) and diffusion-weighted MR imaging in four patients with biopsy-proven Creutzfeldt-Jakob disease. The signal intensity of the lesion was classified by visual assessment as markedly high, slightly high, or isointense, relative to normal brain parenchyma. Both conventional and diffusion-weighted MR images demonstrated bilateral high signal intensity in the basal ganglia in all four patients. Cortical lesions were observed on diffusion-weighted MR images in all four, and on fluidattenuated inversion recovery MR images in one, but in no patient on T2-weighted images. Conventional MR images showed slightly high signal intensity in all lesions, while diffusion-weighted images showed markedly high signal intensity in most. Diffusion-weighted MR imaging is more sensitive than its conventional counterpart in the depiction of Creutzfeldt-Jakob disease, and permits better detection of the lesion in both the cerebral cortices and basal ganglia.

  9. Diffusion-weighted MR imaging in biopsy-proven Creutzfeldt-Jakob disease

    International Nuclear Information System (INIS)

    Kim, Hyo Cheol; Chang, Kee Hyun; Song In Chan; Lee, Sang Hyun; Kwon, Bae Ju; Han, Moon Hee; Kim, Sang Yun

    2001-01-01

    To compare conventional and diffusion-weighted MR imaging in terms of their depiction of the abnormalities occurring in Creutzfeldt-Jakob disease. We retrospectively analyzed the findings of conventional (T2-weighted and fluid-attenuated inversion recovery) and diffusion-weighted MR imaging in four patients with biopsy-proven Creutzfeldt-Jakob disease. The signal intensity of the lesion was classified by visual assessment as markedly high, slightly high, or isointense, relative to normal brain parenchyma. Both conventional and diffusion-weighted MR images demonstrated bilateral high signal intensity in the basal ganglia in all four patients. Cortical lesions were observed on diffusion-weighted MR images in all four, and on fluidattenuated inversion recovery MR images in one, but in no patient on T2-weighted images. Conventional MR images showed slightly high signal intensity in all lesions, while diffusion-weighted images showed markedly high signal intensity in most. Diffusion-weighted MR imaging is more sensitive than its conventional counterpart in the depiction of Creutzfeldt-Jakob disease, and permits better detection of the lesion in both the cerebral cortices and basal ganglia

  10. Contemporary imaging of mild TBI: the journey toward diffusion tensor imaging to assess neuronal damage.

    Science.gov (United States)

    Fox, W Christopher; Park, Min S; Belverud, Shawn; Klugh, Arnett; Rivet, Dennis; Tomlin, Jeffrey M

    2013-04-01

    To follow the progression of neuroimaging as a means of non-invasive evaluation of mild traumatic brain injury (mTBI) in order to provide recommendations based on reproducible, defined imaging findings. A comprehensive literature review and analysis of contemporary published articles was performed to study the progression of neuroimaging findings as a non-invasive 'biomarker' for mTBI. Multiple imaging modalities exist to support the evaluation of patients with mTBI, including ultrasound (US), computed tomography (CT), single photon emission computed tomography (SPECT), positron emission tomography (PET), and magnetic resonance imaging (MRI). These techniques continue to evolve with the development of fractional anisotropy (FA), fiber tractography (FT), and diffusion tensor imaging (DTI). Modern imaging techniques, when applied in the appropriate clinical setting, may serve as a valuable tool for diagnosis and management of patients with mTBI. An understanding of modern neuroanatomical imaging will enhance our ability to analyse injury and recognize the manifestations of mTBI.

  11. A nu-space for image correlation spectroscopy: characterization and application to measure protein transport in live cells

    Science.gov (United States)

    Potvin-Trottier, Laurent; Chen, Lingfeng; Horwitz, Alan Rick; Wiseman, Paul W.

    2013-08-01

    We introduce a new generalized theoretical framework for image correlation spectroscopy (ICS). Using this framework, we extend the ICS method in time-frequency (ν, nu) space to map molecular flow of fluorescently tagged proteins in individual living cells. Even in the presence of a dominant immobile population of fluorescent molecules, nu-space ICS (nICS) provides an unbiased velocity measurement, as well as the diffusion coefficient of the flow, without requiring filtering. We also develop and characterize a tunable frequency-filter for spatio-temporal ICS (STICS) that allows quantification of the density, the diffusion coefficient and the velocity of biased diffusion. We show that the techniques are accurate over a wide range of parameter space in computer simulation. We then characterize the retrograde flow of adhesion proteins (α6- and αLβ2-GFP integrins and mCherry-paxillin) in CHO.B2 cells plated on laminin and intercellular adhesion molecule 1 (ICAM-1) ligands respectively. STICS with a tunable frequency filter, in conjunction with nICS, measures two new transport parameters, the density and transport bias coefficient (a measure of the diffusive character of a flow/biased diffusion), showing that molecular flow in this cell system has a significant diffusive component. Our results suggest that the integrin-ligand interaction, along with the internal myosin-motor generated force, varies for different integrin-ligand pairs, consistent with previous results.

  12. Diffusion weighted imaging with circularly polarized oscillating gradients

    DEFF Research Database (Denmark)

    Lundell, Henrik; Sønderby, Casper Kaae; Dyrby, Tim B

    2015-01-01

    presented. One major hurdle in practical implementation is the low effective diffusion weighting provided at high frequency with limited gradient strength. THEORY: As a solution to the low diffusion weighting of OGSE, circularly polarized OGSE (CP-OGSE) is introduced. CP-OGSE gives a twofold increase...

  13. Imaging features of diffuse pulmonary hemorrhage; Roentgenmorphologie von diffusen Lungenhaemorrhagien

    Energy Technology Data Exchange (ETDEWEB)

    Schmit, M.; Vogel, W.; Horger, M.

    2006-09-15

    There are diverse etiologies of diffuse pulmonary hemorrhage, so specific diagnosis may be difficult. Conventional radiography tends to be misleading as hemoptysis may lacking in patients with hemorrhagic anemia. Diffuse pulmonary hemorrhage should be differentiated from focal pulmonary hemorrhage resulting from chronic bronchitis, bronchiectasis, active infection (tuberculosis) neoplasia, trauma, or embolism. (orig.)

  14. Diffusion weighted imaging demystified. The technique and potential clinical applications for soft tissue imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ahlawat, Shivani [The Johns Hopkins Medical Institutions, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Fayad, Laura M. [The Johns Hopkins Medical Institutions, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); The Johns Hopkins Medical Institutions, Department of Oncology, Baltimore, MD (United States); The Johns Hopkins Medical Institutions, Department of Orthopaedic Surgery, Baltimore, MD (United States)

    2018-03-15

    Diffusion-weighted imaging (DWI) is a fast, non-contrast technique that is readily available and easy to integrate into an existing imaging protocol. DWI with apparent diffusion coefficient (ADC) mapping offers a quantitative metric for soft tissue evaluation and provides information regarding the cellularity of a region of interest. There are several available methods of performing DWI, and artifacts and pitfalls must be considered when interpreting DWI studies. This review article will review the various techniques of DWI acquisition and utility of qualitative as well as quantitative methods of image interpretation, with emphasis on optimal methods for ADC measurement. The current clinical applications for DWI are primarily related to oncologic evaluation: For the assessment of de novo soft tissue masses, ADC mapping can serve as a useful adjunct technique to routine anatomic sequences for lesion characterization as cyst or solid and, if solid, benign or malignant. For treated soft tissue masses, the role of DWI/ADC mapping in the assessment of treatment response as well as recurrent or residual neoplasm in the setting of operative management is discussed, especially when intravenous contrast medium cannot be given. Emerging DWI applications for non-neoplastic clinical indications are also reviewed. (orig.)

  15. Diffusion weighted imaging demystified. The technique and potential clinical applications for soft tissue imaging

    International Nuclear Information System (INIS)

    Ahlawat, Shivani; Fayad, Laura M.

    2018-01-01

    Diffusion-weighted imaging (DWI) is a fast, non-contrast technique that is readily available and easy to integrate into an existing imaging protocol. DWI with apparent diffusion coefficient (ADC) mapping offers a quantitative metric for soft tissue evaluation and provides information regarding the cellularity of a region of interest. There are several available methods of performing DWI, and artifacts and pitfalls must be considered when interpreting DWI studies. This review article will review the various techniques of DWI acquisition and utility of qualitative as well as quantitative methods of image interpretation, with emphasis on optimal methods for ADC measurement. The current clinical applications for DWI are primarily related to oncologic evaluation: For the assessment of de novo soft tissue masses, ADC mapping can serve as a useful adjunct technique to routine anatomic sequences for lesion characterization as cyst or solid and, if solid, benign or malignant. For treated soft tissue masses, the role of DWI/ADC mapping in the assessment of treatment response as well as recurrent or residual neoplasm in the setting of operative management is discussed, especially when intravenous contrast medium cannot be given. Emerging DWI applications for non-neoplastic clinical indications are also reviewed. (orig.)

  16. MR imaging of hypoglycemic encephalopathy: lesion distribution and prognosis prediction by diffusion-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jeong-Hyun; Kim, Young-Joo; Yoo, Won-Jong; Ihn, Yon-Kwon; Kim, Jee-Young; Kim, Bum-Soo [The Catholic University of Korea, Department of Radiology, College of Medicine, Uijongbu, Kyunggi-do (Korea); Song, Ha-Hun [Cheju Halla General Hospital, Department of Radiology, Jeju (Korea)

    2009-10-15

    The aim of this study was to evaluate the patterns of hypoglycemic encephalopathy on diffusion-weighted imaging (DWI) and the relationship between the imaging patterns and clinical outcomes. This retrospective study included 17 consecutive patients that had hypoglycemic encephalopathy with DWI abnormalities. The topographic distributions of the DWI abnormalities of the cortex, deep gray matter, and white matter structures were assessed. In addition, possible correlation between the patterns of brain injury on DWI and clinical outcomes was investigated. There were three patterns of DWI abnormalities: involvement of both gray and white matter (n=8), selective involvement of gray matter (n=4), and selective involvement of white matter (n=5). There was no significant difference in the initial blood glucose levels among patients for each of the imaging patterns. Most patients (16/17) had bilateral symmetrical abnormalities. Among patients with bilateral symmetrical gray and/or white matter injuries, one had moderate to severe disability and 14 remained in a persistent vegetative state. The two patients with a focal unilateral white matter abnormality and a localized splenial abnormality recovered without neurological deficits. The results of this study showed that white matter was more sensitive to hypoglycemia than previously thought and there was no specific association between the patterns of injury and clinical outcomes whether the cerebral cortex, deep gray matter, and/or white matter were affected. Diffuse and extensive injury observed on the DWI predicts a poor neurologic outcome in patients with hypoglycemic injuries. (orig.)

  17. A preliminary diffusional kurtosis imaging study of Parkinson disease: comparison with conventional diffusion tensor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kamagata, Koji; Kamiya, Kouhei; Suzuki, Michimasa; Hori, Masaaki; Yoshida, Mariko; Aoki, Shigeki [Juntendo University School of Medicine, Department of Radiology, Bunkyo-ku, Tokyo (Japan); Tomiyama, Hiroyuki; Hatano, Taku; Motoi, Yumiko; Hattori, Nobutaka [Juntendo University School of Medicine, Department of Neurology, Tokyo (Japan); Abe, Osamu [Nihon University School of Medicine, Department of Radiology, Tokyo (Japan); Shimoji, Keigo [National Center of Neurology and Psychiatry Hospital, Department of Radiology, Tokyo (Japan)

    2014-03-15

    Diffusional kurtosis imaging (DKI) is a more sensitive technique than conventional diffusion tensor imaging (DTI) for assessing tissue microstructure. In particular, it quantifies the microstructural integrity of white matter, even in the presence of crossing fibers. The aim of this preliminary study was to compare how DKI and DTI show white matter alterations in Parkinson disease (PD). DKI scans were obtained with a 3-T magnetic resonance imager from 12 patients with PD and 10 healthy controls matched by age and sex. Tract-based spatial statistics were used to compare the mean kurtosis (MK), mean diffusivity (MD), and fractional anisotropy (FA) maps of the PD patient group and the control group. In addition, a region-of-interest analysis was performed for the area of the posterior corona radiata and superior longitudinal fasciculus (SLF) fiber crossing. FA values in the frontal white matter were significantly lower in PD patients than in healthy controls. Reductions in MK occurred more extensively throughout the brain: in addition to frontal white matter, MK was lower in the parietal, occipital, and right temporal white matter. The MK value of the area of the posterior corona radiata and SLF fiber crossing was also lower in the PD group. DKI detects changes in the cerebral white matter of PD patients more sensitively than conventional DTI. In addition, DKI is useful for evaluating crossing fibers. By providing a sensitive index of brain pathology in PD, DKI may enable improved monitoring of disease progression. (orig.)

  18. Imaging FTS: A Different Approach to Integral Field Spectroscopy

    Directory of Open Access Journals (Sweden)

    Laurent Drissen

    2014-01-01

    Full Text Available Imaging Fourier transform spectroscopy (iFTS is a promising, although technically very challenging, option for wide-field hyperspectral imagery. We present in this paper an introduction to the iFTS concept and its advantages and drawbacks, as well as examples of data obtained with a prototype iFTS, SpIOMM, attached to the 1.6 m telescope of the Observatoire du Mont-Mégantic: emission line ratios in the spiral galaxy NGC 628 and absorption line indices in the giant elliptical M87. We conclude by introducing SpIOMM's successor, SITELLE, which will be installed at the Canada-France-Hawaii Telescope in 2014.

  19. Slow photoelectron imaging spectroscopy of CCO- and CCS-.

    Science.gov (United States)

    Garand, Etienne; Yacovitch, Tara I; Neumark, Daniel M

    2008-08-21

    High-resolution photodetachment spectra of CCO(-) and CCS(-) using slow photoelectron velocity-map imaging spectroscopy are reported. Well-resolved transitions to the neutral X (3)Sigma(-), a (1)Delta, b (1)Sigma(+), and A (3)Pi states are seen for both species. The electron affinities of CCO and CCS are determined to be 2.3107+/-0.0006 and 2.7475+/-0.0006 eV, respectively, and precise term energies for the a (1)Delta, b (1)Sigma(+), and A (3)Pi excited states are also determined. The two low-lying singlet states of CCS are observed for the first time, as are several vibronic transitions within the four bands. Analysis of hot bands finds the spin-orbit orbit splitting in the X (2)Pi ground state of CCO(-) and CCS(-) to be 61 and 195 cm(-1), respectively.

  20. MRI-Guided Diffuse Optical Spectroscopy of Malignant and Benign Breast Lesions

    Directory of Open Access Journals (Sweden)

    Vasilis Ntziachristos

    2002-01-01

    Full Text Available We present the clinical implementation of a novel hybrid system that combines magnetic resonance imaging (MRI and near-infrared (NIR optical measurements for the noninvasive study of breast cancer in vivo. Fourteen patients were studied with a MR-NIR prototype imager and spectrometer. A diffuse optical tomographic scheme employed the MR images as a priori information to implement an image-guided NIR localized spectroscopic scheme. All patients who entered the study also underwent gadolinium-enhanced MRI and biopsy so that the optical findings were crossvalidated with MR readings and histopathology. The technique quantified the oxy-and deoxyhemoglobin of five malignant and nine benign breast lesions in vivo. Breast cancers were found with decreased oxygen saturation and higher blood concentration than most benign lesions. The average hemoglobin concentration ([H] of cancers was 0.130±0.100 mM, and the average hemoglobin saturation (Y was 60±9% compared to [H]=0.018±0.005 mM and Y=69±6% of background tissue. Fibroadenomas exhibited high hemoglobin concentration [H]=0.060±0.010 mM and mild decrease in oxygen saturation Y=67±2%. Cysts and other normal lesions were easily differentiated based on intrinsic contrast information. This novel optical technology can be a significant add-on in MR examinations and can be used to characterize functional parameters of cancers with diagnostic and treatment prognosis potential. It is foreseen that the technique can play a major role in functional activation studies of brain and muscle as well.

  1. An Efficient Diffusion Scheme for Chaos-Based Digital Image Encryption

    Directory of Open Access Journals (Sweden)

    Jun-xin Chen

    2014-01-01

    Full Text Available In recent years, amounts of permutation-diffusion architecture-based image cryptosystems have been proposed. However, the key stream elements in the diffusion procedure are merely depending on the secret key that is usually fixed during the whole encryption process. Cryptosystems of this type suffer from unsatisfactory encryption speed and are considered insecure upon known/chosen plaintext attacks. In this paper, an efficient diffusion scheme is proposed. This scheme consists of two diffusion procedures, with a supplementary diffusion procedure padded after the normal diffusion. In the supplementary diffusion module, the control parameter of the selected chaotic map is altered by the resultant image produced after the normal diffusion operation. As a result, a slight difference in the plain image can be transferred to the chaotic iteration and bring about distinct key streams, and hence totally different cipher images will be produced. Therefore, the scheme can remarkably accelerate the diffusion effect of the cryptosystem and will effectively resist known/chosen plaintext attacks. Theoretical analyses and experimental results prove the high security performance and satisfactory operation efficiency of the proposed scheme.

  2. Multi-Shell Hybrid Diffusion Imaging (HYDI) at 7 Tesla in TgF344-AD Transgenic Alzheimer Rats

    OpenAIRE

    Daianu, Madelaine; Jacobs, Russell E.; Weitz, Tara M.; Town, Terrence C.; Thompson, Paul M.

    2015-01-01

    Diffusion weighted imaging (DWI) is widely used to study microstructural characteristics of the brain. Diffusion tensor imaging (DTI) and high-angular resolution imaging (HARDI) are frequently used in radiology and neuroscience research but can be limited in describing the signal behavior in composite nerve fiber structures. Here, we developed and assessed the benefit of a comprehensive diffusion encoding scheme, known as hybrid diffusion imaging (HYDI), composed of 300 DWI volumes acquired a...

  3. Early detection of neuropathophysiology using diffusion-weighted magnetic resonance imaging in asymptomatic cats with feline immunodeficiency viral infection.

    Science.gov (United States)

    Bucy, Daniel S; Brown, Mark S; Bielefeldt-Ohmann, Helle; Thompson, Jesse; Bachand, Annette M; Morges, Michelle; Elder, John H; Vandewoude, Sue; Kraft, Susan L

    2011-08-01

    HIV infection results in a highly prevalent syndrome of cognitive and motor disorders designated as HIV-associated dementia (HAD). Neurologic dysfunction resembling HAD has been documented in cats infected with strain PPR of the feline immunodeficiency virus (FIV), whereas another highly pathogenic strain (C36) has not been known to cause neurologic signs. Animals experimentally infected with equivalent doses of FIV-C36 or FIV-PPR, and uninfected controls were evaluated by magnetic resonance diffusion-weighted imaging (DW-MRI) and spectroscopy (MRS) at 17.5-18 weeks post-infection, as part of a study of viral clade pathogenesis in FIV-infected cats. The goals of the MR imaging portion of the project were to determine whether this methodology was capable of detecting early neuropathophysiology in the absence of outward manifestation of neurological signs and to compare the MR imaging results for the two viral strains expected to have differing degrees of neurologic effects. We hypothesized that there would be increased diffusion, evidenced by the apparent diffusion coefficient as measured by DW-MRI, and altered metabolite ratios measured by MRS, in the brains of FIV-PPR-infected cats relative to C36-infected cats and uninfected controls. Increased apparent diffusion coefficients were seen in the white matter, gray matter, and basal ganglia of both the PPR and C36-infected (asymptomatic) cats. Thalamic MRS metabolite ratios did not differ between groups. The equivalently increased diffusion by DW-MRI suggests similar indirect neurotoxicity mechanisms for the two viral genotypes. DW-MRI is a sensitive tool to detect neuropathophysiological changes in vivo that could be useful during longitudinal studies of FIV.

  4. Regional diffusion changes of cerebral grey matter during normal aging-A fluid-inversion prepared diffusion imaging study

    International Nuclear Information System (INIS)

    Ni Jianming; Chen Shuang; Liu Jianjun; Huang Gang; Shen Tianzhen; Chen Xingrong

    2010-01-01

    Background and purpose: Although diffusion characteristics of white matter (WM) and its aging effects have been well described in the literature, diffusion characteristics of grey matter (GM), especially the cortical GM, have not been fully evaluated. In the present study, we used the fluid-inversion prepared diffusion imaging (FLIPD) technique to determine if there are age-related water diffusivity changes in GM. Materials and methods: 120 healthy volunteers were recruited for our study. They were divided into three age groups: group one (20-39 years old), group two (40-59 years old) and group three (60 years or older). All patients were evaluated with MRI using FLIPD at 3.0 T. Apparent diffusion coefficient (ADC) values of the frontal GM, cingulate cortex and thalami were determined bilaterally by region-of-interest analysis. Results: Group three had significantly higher ADC values in both thalami and the left frontal GM compared to group two or group one. No ADC value difference was found among the three groups in the right frontal GM and bilateral cingulate cortex. There was a significant positive correlation between individual ADC values and age in both thalami and left frontal GM. For the cingulate cortex and the right frontal GM, ADC values did not correlate significantly with advancing age. Conclusion: Statistically significant age-related diffusion changes were observed in both thalami and the left frontal cortex. The data reported here may serve as a reference for future studies.

  5. Investigation of a phantom for diffusion weighted imaging that controlled the apparent diffusion coefficient using gelatin and sucrose

    International Nuclear Information System (INIS)

    Tamura, Takayuki; Usui, Shuji; Akiyama, Mitoshi

    2009-01-01

    When studying diffusion weighted imaging (DWI), it is important to create a phantom that has a reliably controlled diffusion coefficient. In this study, we investigated phantoms to control both the diffusion coefficient and the T2-value by changing the concentration of gelatin or sucrose and MnCl 2 , respectively. The results showed that the diffusion coefficient decreased linearly with increases in the gelatin or sucrose concentration, and decreasing of their relaxation times was observed. By properly adjusting the MnCl 2 concentrations, we were able to equalize the T2-values between phantoms having different gelatin or sucrose concentrations. Temperature dependence of the diffusion coefficient was also revealed. This phantom can be made stable for a few months by adding a small amount of NaN 3 as an antiseptic agent, has a diffusion coefficient similar to that of neural tissue or clinical tumor, and is able to control the T2-value properly. We consider this phantom suitable for studying SE-type DWI and contributes to elucidation of this technique. (author)

  6. SOLARNET & LAIME: Imaging & Spectroscopy in the Far Ultraviolet

    Science.gov (United States)

    Damé, Luc; Koutchmy, Serge

    SOLARNET is a medium size high resolution solar physics mission proposed to CNES and ESA for a new start in 2007 and a possible launch in 2012 (CNES) or later (ESA Cosmic Vision framework: 2015-2016). Partnerships with India and China are under discussion, and several European contributions are considered. At the center of the SOLARNET mission is a 3-telescope interferometer of 1 meter baseline capable to provide 40 times the best ever spatial resolution achieved in Space with previous, current or even planned solar missions: 20 mas - 20 km on the Sun in the FUV. The interferometer is associated to an on-axis Subtractive Double Monochromator coupled to an Imaging Fourier Transform Spectrometer capable of high spectral (0.01 nm) and high temporal resolutions (50 ms) on a field of view of 40 arcsec and covering the FUV and UV spectral domains (from 117.5 to 400 nm). This will allow to access process scales of magnetic reconnection, dissipation, emerging flux and much more, from the chromosphere to the low corona with emphasis on the transition zone where the magnetic confinement is expected to be maximum. A whole new chapter of the physics of solar magnetic field structuring, evolution and mapping from the photosphere to the high atmosphere will be opened. The interferometer is completed by instruments providing larger field of view and higher temperature (EUV-XUV coronal imaging & spectroscopy) to define the context and extension of the solar phenomena. The 3-telescope interferometer design results of an extensive laboratory demonstration program of interferometric imaging of extended objects. We will review the scientific program of SOLARNET, describe the interferometer concept and design, present the results of the breadboard and give a short overview of the mission aspects. In a different category, LAIME, the Lyman Alpha Imaging-Monitor Experiment, is a remarkably simple (no mechanisms) and compact full Sun imager to be flown with TESIS on the CORONAS

  7. Pediatric littoral cell angioma of the spleen: multimodality imaging including diffusion-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ertan, Gulhan; Tekes, Aylin; Huisman, Thierry A.G.M. [Johns Hopkins Hospital, Division of Pediatric Radiology, Department of Radiology and Radiological Science, Baltimore, MD (United States); Mitchell, Sally [Johns Hopkins Hospital, Division of Cardiovascular and Interventional Radiology, Department of Radiology and Radiological Science, Baltimore (United States); Keefer, Jeffrey [Johns Hopkins Hospital, Division of Pediatric Hematology, Department of Pediatrics, Baltimore, MD (United States)

    2009-10-15

    Littoral cell angioma (LCA) is a rare primary splenic vascular tumor originating from littoral cells lining the splenic red pulp sinuses. LCAs are rarely seen in children. We present the US, CT, and MRI findings including diffusion-weighted imaging (DWI) in a 2-year-old boy with histologically proven LCA. Previous studies on liver lesions have shown that DWI allows differentiation of vascular tumors from primary neoplasms and metastatic disease. The current case indicates that increased ADC values within the splenic lesions suggest a vascular etiology, which might help narrow the differential diagnosis. (orig.)

  8. Pediatric littoral cell angioma of the spleen: multimodality imaging including diffusion-weighted imaging

    International Nuclear Information System (INIS)

    Ertan, Gulhan; Tekes, Aylin; Huisman, Thierry A.G.M.; Mitchell, Sally; Keefer, Jeffrey

    2009-01-01

    Littoral cell angioma (LCA) is a rare primary splenic vascular tumor originating from littoral cells lining the splenic red pulp sinuses. LCAs are rarely seen in children. We present the US, CT, and MRI findings including diffusion-weighted imaging (DWI) in a 2-year-old boy with histologically proven LCA. Previous studies on liver lesions have shown that DWI allows differentiation of vascular tumors from primary neoplasms and metastatic disease. The current case indicates that increased ADC values within the splenic lesions suggest a vascular etiology, which might help narrow the differential diagnosis. (orig.)

  9. Clinical application of diffusion-weighted magnetic resonance imaging to intracranial disorders

    Energy Technology Data Exchange (ETDEWEB)

    Yanaka, Kiyoyuki; Shirai, Shizuo; Kimura, Hiroshi [Soujinkai Hospital, Ibaraki (Japan); Kamezaki, Takao; Matsumura, Akira; Nose, Tadao

    1995-09-01

    Diffusion-weighted magnetic resonance imaging was performed to determine the changes in water diffusion and to investigate the detectability of diffusion anisotropy in patients with intracranial disorders. Diffusion maps of the apparent diffusion coefficient (ADC) were created of 19 patients with cerebral infarction, five with intracerebral hematoma, four with glioma, four with meningioma, four with hydrocephalus, and five with subdural hematoma. ADC was increased in chronic cerebral infarction and glioma, and decreased in acute cerebral infarction, meningioma, and the marginal area of glioma compared with the ADC of the normal gray matter. There was a significant difference in ADC between the marginal and internal areas of glioma. Increased ADC may be due to increased vasogenic edema in infarction and a lack of significant restriction of diffusion within glioma. Decreased ADC can be attributed to restricted diffusion caused by cytotoxic edema in infarction and the underlying histological pattern of densely packed tumor cells in glioma. Diffusion anisotropy of the internal capsule was less detectable in pathological than normal hemispheres. Diffusion anisotropy was less detectable in patients with hydrocephalus and subdural hematoma. Intracranial lesions were thought to have influenced the compression of the brain structures and cells, resulting in decreased diffusion. The measurement of ADC by diffusion-weighted magnetic resonance imaging has the potential for greater understanding of the biophysical changes in various intracranial disorders, including correct diagnosis of cerebral infarction, and histological diagnosis of brain tumor. (author).

  10. Incidence of postangiographic silent brain infarction detected by diffusion-weighted MR imaging

    International Nuclear Information System (INIS)

    Mori, Harushi; Hayashi, Naoto; Aoki, Shigeki

    2002-01-01

    We surveyed to assess for the incidence of clinically silent brain infarction after cerebral catheter angiography. Diffusion-weighted images were performed shortly after 33 cerebral catheter angiographies. We found totally 11 abnormally high intensity spots in 5 of 33 patients on diffusion-weighted images and, therefore, the incidence was calculated as 15.2%. This incidence is higher than has been estimated based on the incidence of neurological deficits (about 0.5%) after cerebral angiography. Diffusion-weighted MR imaging is suitable to monitor the safety of angiographic procedures and material. (author)

  11. Diagnosis of pericardial cysts using diffusion weighted magnetic resonance imaging: A case series

    Directory of Open Access Journals (Sweden)

    Mousavi Negareh

    2011-09-01

    Full Text Available Abstract Introduction Congenital pericardial cysts are benign lesions that arise from the pericardium during embryonic development. The diagnosis is based on typical imaging features, but atypical locations and signal magnetic resonance imaging sequences make it difficult to exclude other lesions. Diffusion-weighted magnetic resonance imaging is a novel method that can be used to differentiate tissues based on their restriction to proton diffusion. Its use in differentiating pericardial cysts from other pericardial lesions has not yet been described. Case presentation We present three cases (a 51-year-old Caucasian woman, a 66-year-old Caucasian woman and a 77-year-old Caucasian woman with pericardial cysts evaluated with diffusion-weighted imaging using cardiac magnetic resonance imaging. Each lesion demonstrated a high apparent diffusion coefficient similar to that of free water. Conclusion This case series is the first attempt to investigate the utility of diffusion-weighted magnetic resonance imaging in the assessment of pericardial cysts. Diffusion-weighted imaging may be a useful noninvasive diagnostic tool for pericardial cysts when conventional imaging findings are inconclusive.

  12. Pixel detectors for x-ray imaging spectroscopy in space

    International Nuclear Information System (INIS)

    Treis, J; Andritschke, R; Hartmann, R; Herrmann, S; Holl, P; Lauf, T; Lechner, P; Lutz, G; Meidinger, N; Porro, M; Richter, R H; Schopper, F; Soltau, H; Strueder, L

    2009-01-01

    Pixelated semiconductor detectors for X-ray imaging spectroscopy are foreseen as key components of the payload of various future space missions exploring the x-ray sky. Located on the platform of the new Spectrum-Roentgen-Gamma satellite, the eROSITA (extended Roentgen Survey with an Imaging Telescope Array) instrument will perform an imaging all-sky survey up to an X-ray energy of 10 keV with unprecedented spectral and angular resolution. The instrument will consist of seven parallel oriented mirror modules each having its own pnCCD camera in the focus. The satellite born X-ray observatory SIMBOL-X will be the first mission to use formation-flying techniques to implement an X-ray telescope with an unprecedented focal length of around 20 m. The detector instrumentation consists of separate high- and low energy detectors, a monolithic 128 x 128 DEPFET macropixel array and a pixellated CdZTe detector respectively, making energy band between 0.5 to 80 keV accessible. A similar concept is proposed for the next generation X-ray observatory IXO. Finally, the MIXS (Mercury Imaging X-ray Spectrometer) instrument on the European Mercury exploration mission BepiColombo will use DEPFET macropixel arrays together with a small X-ray telescope to perform a spatially resolved planetary XRF analysis of Mercury's crust. Here, the mission concepts and their scientific targets are briefly discussed, and the resulting requirements on the detector devices together with the implementation strategies are shown.

  13. Pixel detectors for x-ray imaging spectroscopy in space

    Science.gov (United States)

    Treis, J.; Andritschke, R.; Hartmann, R.; Herrmann, S.; Holl, P.; Lauf, T.; Lechner, P.; Lutz, G.; Meidinger, N.; Porro, M.; Richter, R. H.; Schopper, F.; Soltau, H.; Strüder, L.

    2009-03-01

    Pixelated semiconductor detectors for X-ray imaging spectroscopy are foreseen as key components of the payload of various future space missions exploring the x-ray sky. Located on the platform of the new Spectrum-Roentgen-Gamma satellite, the eROSITA (extended Roentgen Survey with an Imaging Telescope Array) instrument will perform an imaging all-sky survey up to an X-ray energy of 10 keV with unprecedented spectral and angular resolution. The instrument will consist of seven parallel oriented mirror modules each having its own pnCCD camera in the focus. The satellite born X-ray observatory SIMBOL-X will be the first mission to use formation-flying techniques to implement an X-ray telescope with an unprecedented focal length of around 20 m. The detector instrumentation consists of separate high- and low energy detectors, a monolithic 128 × 128 DEPFET macropixel array and a pixellated CdZTe detector respectively, making energy band between 0.5 to 80 keV accessible. A similar concept is proposed for the next generation X-ray observatory IXO. Finally, the MIXS (Mercury Imaging X-ray Spectrometer) instrument on the European Mercury exploration mission BepiColombo will use DEPFET macropixel arrays together with a small X-ray telescope to perform a spatially resolved planetary XRF analysis of Mercury's crust. Here, the mission concepts and their scientific targets are briefly discussed, and the resulting requirements on the detector devices together with the implementation strategies are shown.

  14. Pixel detectors for x-ray imaging spectroscopy in space

    Energy Technology Data Exchange (ETDEWEB)

    Treis, J; Andritschke, R; Hartmann, R; Herrmann, S; Holl, P; Lauf, T; Lechner, P; Lutz, G; Meidinger, N; Porro, M; Richter, R H; Schopper, F; Soltau, H; Strueder, L [MPI Semiconductor Laboratory, Otto-Hahn-Ring 6, D-81739 Munich (Germany)], E-mail: jft@hll.mpg.de

    2009-03-15

    Pixelated semiconductor detectors for X-ray imaging spectroscopy are foreseen as key components of the payload of various future space missions exploring the x-ray sky. Located on the platform of the new Spectrum-Roentgen-Gamma satellite, the eROSITA (extended Roentgen Survey with an Imaging Telescope Array) instrument will perform an imaging all-sky survey up to an X-ray energy of 10 keV with unprecedented spectral and angular resolution. The instrument will consist of seven parallel oriented mirror modules each having its own pnCCD camera in the focus. The satellite born X-ray observatory SIMBOL-X will be the first mission to use formation-flying techniques to implement an X-ray telescope with an unprecedented focal length of around 20 m. The detector instrumentation consists of separate high- and low energy detectors, a monolithic 128 x 128 DEPFET macropixel array and a pixellated CdZTe detector respectively, making energy band between 0.5 to 80 keV accessible. A similar concept is proposed for the next generation X-ray observatory IXO. Finally, the MIXS (Mercury Imaging X-ray Spectrometer) instrument on the European Mercury exploration mission BepiColombo will use DEPFET macropixel arrays together with a small X-ray telescope to perform a spatially resolved planetary XRF analysis of Mercury's crust. Here, the mission concepts and their scientific targets are briefly discussed, and the resulting requirements on the detector devices together with the implementation strategies are shown.

  15. Total Internal Reflection Fluorescence Microscopy Imaging-Guided Confocal Single-Molecule Fluorescence Spectroscopy

    OpenAIRE

    Zheng, Desheng; Kaldaras, Leonora; Lu, H. Peter

    2013-01-01

    We have developed an integrated spectroscopy system combining total internal reflection fluorescence microscopy imaging with confocal single-molecule fluorescence spectroscopy for two-dimensional interfaces. This spectroscopy approach is capable of both multiple molecules simultaneously sampling and in situ confocal fluorescence dynamics analyses of individual molecules of interest. We have demonstrated the calibration with fluorescent microspheres, and carried out single-molecule spectroscop...

  16. Functional evaluation of hydronephrosis by diffusion-weighted MR imaging: Relationship between apparent diffusion coefficient and split glomerular filtration rate

    International Nuclear Information System (INIS)

    Toyoshima, S.; Noguchi, K.; Seto, H.; Shimizu, M.; Watanabe, N.

    2000-01-01

    To determine the relationship between apparent diffusion coefficient (ADC) values measured by diffusion-weighted MR imaging and split renal function determined by renal scintigraphy in patients with hydronephrosis. Material and Methods: Diffusion-weighted imaging on a 1.5 T MR unit and renal scintigraphy were performed in 36 patients with hydronephrosis (45 hydronephrotic kidneys, 21 non-hydronephrotic kidneys). ADC values of the individual kidneys were measured by diffusion-weighted MR imaging. Split renal function (glomerular filtration rate (GFR)) was determined by renal scintigraphy using 99m Tc-DTPA. The relationship between ADC values and split GFR was examined in 66 kidneys. The hydronephrotic kidneys were further classified into three groups (severe renal dysfunction, GFR 25 ml/min, n=28), and mean values for ADCs were calculated. Results: In hydronephrotic kidneys, there was a moderate positive correlation between ADC values and split GFR (R2=0.56). On the other hand, in non-hydronephrotic kidneys, poor correlation between ADC values and split GFR was observed (R2=0.08). The mean values for ADCs of the dysfunctioning hydronephrotic kidneys (severe renal dysfunction, 1.32x10 -3 ±0.18x10 -3 mm 2 /s; moderate renal dysfunction, 1.38x10 -3 ±0.10x10 -3 mm2/s) were significantly lower than that of the normal functioning hydronephrotic kidneys (1.63x10 -3 ±0.12±10 -3 mm 2 /s). Conclusion: These results indicated that measurement of ADC values by diffusion-weighted MR imaging has a potential value in the evaluation of the functional status of hydronephrotic kidneys

  17. Role of diffusion-weighted magnetic resonance imaging in the diagnosis of extrahepatic cholangiocarcinoma

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    AIM: To determine the clinical value of diffusion-weight- ed imaging (DWI) for the diagnosis of extrahepatic cholangiocarcinoma (EHCC) by comparing the diagnostic sensitivity of DWI and magnetic resonance cholan-giopancreatography (MRCP). METHODS: Magnetic resonance imaging examination was performed in 56 patients with suspected EHCC. T1- weighted imaging, T2-weighted imaging, MRCP and DWI sequence, DWI using single-shot spin-echo echoplanar imaging sequence with different b values (100, 300, 500, 800 and 1...

  18. Changes in lumbosacral spinal nerve roots on diffusion tensor imaging in spinal stenosis

    OpenAIRE

    Zhong-jun Hou; Yong Huang; Zi-wen Fan; Xin-chun Li; Bing-yi Cao

    2015-01-01

    Lumbosacral degenerative disc disease is a common cause of lower back and leg pain. Conventional T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI) scans are commonly used to image spinal cord degeneration. However, these modalities are unable to image the entire lumbosacral spinal nerve roots. Thus, in the present study, we assessed the potential of diffusion tensor imaging (DTI) for quantitative assessment of compressed lumbosacral spinal nerve roots. Subjects were 20 young healthy v...

  19. A Quantitative Diffuse Reflectance Imaging (QDRI) System for Comprehensive Surveillance of the Morphological Landscape in Breast Tumor Margins.

    Science.gov (United States)

    Nichols, Brandon S; Schindler, Christine E; Brown, Jonathon Q; Wilke, Lee G; Mulvey, Christine S; Krieger, Marlee S; Gallagher, Jennifer; Geradts, Joseph; Greenup, Rachel A; Von Windheim, Jesko A; Ramanujam, Nirmala

    2015-01-01

    In an ongoing effort to address the clear clinical unmet needs surrounding breast conserving surgery (BCS), our group has developed a next-generation multiplexed optical-fiber-based tool to assess breast tumor margin status during initial surgeries. Specifically detailed in this work is the performance and clinical validation of a research-grade intra-operative tool for margin assessment based on diffuse optical spectroscopy. Previous work published by our group has illustrated the proof-of-concept generations of this device; here we incorporate a highly optimized quantitative diffuse reflectance imaging (QDRI) system utilizing a wide-field (imaging area = 17 cm(2)) 49-channel multiplexed fiber optic probe, a custom raster-scanning imaging platform, a custom dual-channel white LED source, and an astronomy grade imaging CCD and spectrograph. The system signal to noise ratio (SNR) was found to be greater than 40 dB for all channels. Optical property estimation error was found to be less than 10%, on average, over a wide range of absorption (μa = 0-8.9 cm(-1)) and scattering (μs' = 7.0-9.7 cm(-1)) coefficients. Very low inter-channel and CCD crosstalk was observed (2% max) when used on turbid media (including breast tissue). A raster-scanning mechanism was developed to achieve sub-pixel resolution and was found to be optimally performed at an upsample factor of 8, affording 0.75 mm spatially resolved diffuse reflectance images (λ = 450-600 nm) of an entire margin (area = 17 cm(2)) in 13.8 minutes (1.23 cm(2)/min). Moreover, controlled pressure application at the probe-tissue interface afforded by the imaging platform reduces repeated scan variability, providing operative time scales with improved sensitivity to regions of focal disease that may otherwise be overlooked.

  20. Finsler geometry on higher order tensor fields and applications to high angular resolution diffusion imaging

    NARCIS (Netherlands)

    Astola, L.J.; Florack, L.M.J.

    2011-01-01

    We study 3D-multidirectional images, using Finsler geometry. The application considered here is in medical image analysis, specifically in High Angular Resolution Diffusion Imaging (HARDI) (Tuch et al. in Magn. Reson. Med. 48(6):1358–1372, 2004) of the brain. The goal is to reveal the architecture

  1. Finsler geometry on higher order tensor fields and applications to high angular resolution diffusion imaging.

    NARCIS (Netherlands)

    Astola, L.; Florack, L.

    2011-01-01

    We study 3D-multidirectional images, using Finsler geometry. The application considered here is in medical image analysis, specifically in High Angular Resolution Diffusion Imaging (HARDI) (Tuch et al. in Magn. Reson. Med. 48(6):1358–1372, 2004) of the brain. The goal is to reveal the architecture

  2. Finsler geometry on higher order tensor fields and applications to high angular resolution diffusion imaging

    NARCIS (Netherlands)

    Astola, L.J.; Florack, L.M.J.

    2010-01-01

    We study 3D-multidirectional images, using Finsler geometry. The application considered here is in medical image analysis, specifically in High Angular Resolution Diffusion Imaging (HARDI) [24] of the brain. The goal is to reveal the architecture of the neural fibers in brain white matter. To the

  3. Diffusion tensor imaging of brain in relapsing neuromyelitis optica

    International Nuclear Information System (INIS)

    Yu Chunshui; Li Kuncheng; Qin Wen; Lin Fuchun; Jiang Tianzi

    2007-01-01

    Objective: To investigate the presence of occult brain tissue damage in patients with relapsing neuromyelitis optica (RNMO) and its possible mechanism by using diffusion tensor imaging (DTI). Methods: DTI scans were performed in 16 patients with RNMO and 16 sex- and age-matched healthy controls. Histogram analysis of mean diffusivity (MD) and fractional anisotropy (FA) was performed in brain tissue (BT), white matter (WM) and gray matter (GM) to detect the presence of occult brain tissue damage in RNMO patients. Region of interest (ROI) analysis of MD and FA was also performed in 6 dedicated regions with or without direct connection with spinal cord or optic nerve to determine the relationship between occult brain tissue damage and the damage of spinal cord and optic nerve. Results Patients with RNMO had a significantly higher average MD of the BT [RNMO (0.95 ± 0.02) x 10 -3 mm 2 /s, controls (0.91 ± 0.03) x 10 -3 mm 2 /s, t=3.940, P -3 mm 2 /s, controls(0.80 ± 0.02) x 10 -3 mm 2 /s, t=3.117, P=0.004] an.d GM [RNMO (1.06 ± 0.04) x 10 -3 mm 2 /s, controls (0.88 ± 0.05) x 10 -3 mm 2 /s, t=4.031, P -3 mm 2 /s, controls (0.81 ± 0.02) x 10 -3 mm 2 /s, t=4.373, P -3 mm 2 /s, controls (1.11 ± 0.10) x 10 -3 mm 2 /s, t=4.260, P -3 mm 2 /s, controls (0.87 ± 0.05) x 10 -3 mm 2 /s, t4.391, P -3 mm 2 /s, controls (0.72 ± O.01) x 10 -3 mm 2 /s, t=4.683, P -3 mm 2 /s, controls (0.82+0.03) x 10-3 mm2/s, t = 4. 619, P -3 mm 2 /s, controls (0.73±0.03) x 10 -3 mm 2 /s, t =2.804, P=0.009 and splenium of corpus callosum: RNMO(0.77 ± 0.05) x 10 -3 mm 2 /s, controls (0.73 ± 0.04) x 10 -3 mm 2 /s, t=2.234, P=0.033] and FA [genu of corpus callosum: RNMO 0.82± 0.03 ,controls 0.82 ± 0.03, t=0.196, P=0.846 and splenium of corpus caltosum: RNMO 0.83±0.03, controls 0.83 ± 0.02, t=0.333, P=0.741] between RNMO patients and controls. Conclusion: RNMO patients have occult brain tissue damage, which might be related to the antegrade and retrograde degeneration secondary to lesions in

  4. The Auroral Planetary Imaging and Spectroscopy (APIS) service

    Science.gov (United States)

    Lamy, L.; Prangé, R.; Henry, F.; Le Sidaner, P.

    2015-06-01

    The Auroral Planetary Imaging and Spectroscopy (APIS) service, accessible online, provides an open and interactive access to processed auroral observations of the outer planets and their satellites. Such observations are of interest for a wide community at the interface between planetology, magnetospheric and heliospheric physics. APIS consists of (i) a high level database, built from planetary auroral observations acquired by the Hubble Space Telescope (HST) since 1997 with its mostly used Far-Ultraviolet spectro-imagers, (ii) a dedicated search interface aimed at browsing efficiently this database through relevant conditional search criteria and (iii) the ability to interactively work with the data online through plotting tools developed by the Virtual Observatory (VO) community, such as Aladin and Specview. This service is VO compliant and can therefore also been queried by external search tools of the VO community. The diversity of available data and the capability to sort them out by relevant physical criteria shall in particular facilitate statistical studies, on long-term scales and/or multi-instrumental multi-spectral combined analysis.

  5. Interstitial diffuse radiance spectroscopy of gold nanocages and nanorods in bulk muscle tissues

    Directory of Open Access Journals (Sweden)

    Grabtchak S

    2015-02-01

    converted to the relative density of photons incident on the inclusion. Finally, the experimentally measured quantities were expressed via the relative perturbation and arranged into the classical Beer–Lambert law that allowed one to extract the extinction coefficients of various types of Au nanoparticles in both the transmission and back reflection geometries. It was shown that the spatial variation of perturbation could be described as 1/r dependence, where r is the distance between the inclusion and the detector. Due to a larger absorption cross section, Au nanocages produced greater perturbations than Au nanorods of equal particle concentration, indicating a better suitability of Au nanocages as contrast agents for optical measurements in turbid media. Individual measurements from different inclusions were combined into detectability maps.Keywords: gold nanocages, gold nanorods, turbid media, porcine muscles, diffuse radiance spectroscopy, Beer–Lambert law, perturbation

  6. Diffusion tensor imaging and tractography in clinical neuro sciences

    International Nuclear Information System (INIS)

    Zarei, M.; Johansen-Berg, H.; Matthews, P.M.

    2003-01-01

    Rapidly evolving MR technology has allowed better understanding of structure and function of the human brain. Diffusion weighted MRI was developed two decades ago and it is now well established in diagnosis of acute ischaemia in patients with stroke. Diffusion tensor MRI uses the same principles but takes a step further allowing US to measure magnitude of the diffusion along different directions. This lead to the development of diffusion tensor tractography, a technique by which major neural pathways in the living brain can be visualized. There is a growing interest in exploring possible use of these techniques in clinical neurology and psychiatry. This article aims to review the principles of this technique and recent discoveries which may help US to better understand neurological and psychiatric disorders

  7. Magnetic resonance imaging and spectroscopy at ultra high fields

    International Nuclear Information System (INIS)

    Neuberger, Thomas

    2009-01-01

    The goal of the work presented in this thesis was to explore the possibilities and limitations of MRI / MRS using an ultra high field of 17.6 tesla. A broad range of specific applications and MR methods, from MRI to MRSI and MRS were investigated. The main foci were on sodium magnetic resonance spectroscopic imaging of rodents, magnetic resonance spectroscopy of the mouse brain, and the detection of small amounts of iron labeled stem cells in the rat brain using MRI Sodium spectroscopic imaging was explored since it benefits tremendously from the high magnetic field. Due to the intrinsically low signal in vivo, originating from the low concentrations and short transverse relaxation times, only limited results have been achieved by other researchers until now. Results in the literature include studies conducted on large animals such as dogs to animals as small as rats. No studies performed on mice have been reported, despite the fact that the mouse is the most important laboratory animal due to the ready availability of transgenic strains. Hence, this study concentrated on sodium MRSI of small rodents, mostly mice (brain, heart, and kidney), and in the case of the brain on young rats. The second part of this work concentrated on proton magnetic resonance spectroscopy of the rodent brain. Due to the high magnetic field strength not only the increasing signal but also the extended spectral resolution was advantageous for such kind of studies. The difficulties/limitations of ultra high field MRS were also investigated. In the last part of the presented work detection limits of iron labeled stem cells in vivo using magnetic resonance imaging were explored. The studies provided very useful benchmarks for future researchers in terms of the number of labeled stem cells that are required for high-field MRI studies. Overall this work has shown many of the benefits and the areas that need special attention of ultra high fields in MR. Three topics in MRI, MRS and MRSI were

  8. Magnetic resonance imaging and spectroscopy at ultra high fields

    Energy Technology Data Exchange (ETDEWEB)

    Neuberger, Thomas

    2009-06-23

    The goal of the work presented in this thesis was to explore the possibilities and limitations of MRI / MRS using an ultra high field of 17.6 tesla. A broad range of specific applications and MR methods, from MRI to MRSI and MRS were investigated. The main foci were on sodium magnetic resonance spectroscopic imaging of rodents, magnetic resonance spectroscopy of the mouse brain, and the detection of small amounts of iron labeled stem cells in the rat brain using MRI Sodium spectroscopic imaging was explored since it benefits tremendously from the high magnetic field. Due to the intrinsically low signal in vivo, originating from the low concentrations and short transverse relaxation times, only limited results have been achieved by other researchers until now. Results in the literature include studies conducted on large animals such as dogs to animals as small as rats. No studies performed on mice have been reported, despite the fact that the mouse is the most important laboratory animal due to the ready availability of transgenic strains. Hence, this study concentrated on sodium MRSI of small rodents, mostly mice (brain, heart, and kidney), and in the case of the brain on young rats. The second part of this work concentrated on proton magnetic resonance spectroscopy of the rodent brain. Due to the high magnetic field strength not only the increasing signal but also the extended spectral resolution was advantageous for such kind of studies. The difficulties/limitations of ultra high field MRS were also investigated. In the last part of the presented work detection limits of iron labeled stem cells in vivo using magnetic resonance imaging were explored. The studies provided very useful benchmarks for future researchers in terms of the number of labeled stem cells that are required for high-field MRI studies. Overall this work has shown many of the benefits and the areas that need special attention of ultra high fields in MR. Three topics in MRI, MRS and MRSI were

  9. Role of apparent diffusion coefficient values and diffusion weighted magnetic resonance imaging in differentiation between benign and malignant thyroid nodules

    International Nuclear Information System (INIS)

    Incedayi, M.; Sivrioglu, A.; Mutlu, H.; Sonmez, G.; Velioglu, M.; Sildiroglu, O.; Basekim, C.; Kizilkaya, E.

    2012-01-01

    Full text: Objective: The purpose of the study was to differentiate between benign and malignant thyroid nodules using nodule-spinal cord signal intensity and nodule apparent diffusion coefficient (ADC) ratios on diffusion weighted magnetic resonance imaging. Materials and methods: Forty-four patients (27 females, 17 males; mean age 49) with nodules who underwent diffusion weighted magnetic resonance imaging (DW-MRI) were included in this study. The images were acquired with 0, 50, 400 and 1000 s/mm 2 b values. ADC maps were calculated afterwards. Fine needle aspiration biopsies (FNAB) were performed at the same day with DW-MRI acquisition. The diagnosis in patients where malignity was detected after FNAB was confirmed by histopathologic analysis of the operation material. The signal intensities of the spinal cord and the nodule were measured additionally, over b-1000 diffusion weighted images. Nodule /cord signal intensity (SI) ratios were obtained and the digital values were calculated by dividing to ADC values estimated for each nodule. Statistical analysis was performed. Results: The (nodule SI-cord SI)/nodule ADC ratio is calculated in the DW images and a statistically significant relationship was found between this ratio and the histopathology of the nodules (p<0.001). The ratio was determined as 0.27 in benign, and 0.86 in malignant lesions. The result of ROC analysis was statistically significant, and the area under Receiver Operating Characteristic (ROC) curve (100%) was considerably high. The threshold value was calculated as 0.56 according to the ROC analysis. According to this threshold value, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy rates for (nodule SI/cord SI)/ADC ratios in differentiating benign from malignant thyroid nodules are calculated as 100%, 97%, 83%, 100%, and 98%, respectively. Conclusion: We have found that (nodule/cord SI)/ nodule ADC ratio has the highest values for

  10. Diffusion tensor imaging with direct cytopathological validation: characterisation of decorin treatment in experimental juvenile communicating hydrocephalus.

    Science.gov (United States)

    Aojula, Anuriti; Botfield, Hannah; McAllister, James Patterson; Gonzalez, Ana Maria; Abdullah, Osama; Logan, Ann; Sinclair, Alexandra

    2016-05-31

    In an effort to develop novel treatments for communicating hydrocephalus, we have shown previously that the transforming growth factor-β antagonist, decorin, inhibits subarachnoid fibrosis mediated ventriculomegaly; however decorin's ability to prevent cerebral cytopathology in communicating hydrocephalus has not been fully examined. Furthermore, the capacity for diffusion tensor imaging to act as a proxy measure of cerebral pathology in multiple sclerosis and spinal cord injury has recently been demonstrated. However, the use of diffusion tensor imaging to investigate cytopathological changes in communicating hydrocephalus is yet to occur. Hence, this study aimed to determine whether decorin treatment influences alterations in diffusion tensor imaging parameters and cytopathology in experimental communicating hydrocephalus. Moreover, the study also explored whether diffusion tensor imaging parameters correlate with cellular pathology in communicating hydrocephalus. Accordingly, communicating hydrocephalus was induced by injecting kaolin into the basal cisterns in 3-week old rats followed immediately by 14 days of continuous intraventricular delivery of either human recombinant decorin (n = 5) or vehicle (n = 6). Four rats remained as intact controls and a further four rats served as kaolin only controls. At 14-days post-kaolin, just prior to sacrifice, routine magnetic resonance imaging and magnetic resonance diffusion tensor imaging was conducted and the mean diffusivity, fractional anisotropy, radial and axial diffusivity of seven cerebral regions were assessed by voxel-based analysis in the corpus callosum, periventricular white matter, caudal internal capsule, CA1 hippocampus, and outer and inner parietal cortex. Myelin integrity, gliosis and aquaporin-4 levels were evaluated by post-mortem immunohistochemistry in the CA3 hippocampus and in the caudal brain of the same cerebral structures analysed by diffusion tensor imaging. Decorin significantly

  11. Diffusion MR imaging with PSIF and SPLICE. Experiences in phantom studies and the central nervous system

    International Nuclear Information System (INIS)

    Uchikoshi, Masato; Ueda, Takashi; Kaji, Yasushi

    2001-01-01

    Studies have shown that diffusion MR imaging is a reliable method for the diagnosis of central nervous system diseases, especially acute cerebral infarction. Although echo planar imaging (EPI) is a promising tool for that purpose, it is vulnerable to susceptibility artifacts that are responsible for image distortion or signal loss. Our purpose in this study was to evaluate the usefulness of diffusion MR imaging with PSIF (reversed fast imaging SSFP) and split acquisition of fast-spin-echo signals for diffusion imaging (SPLICE) in the central nervous system (CNS). First, PSIF and SPLICE were applied to the phantoms. Each phantom, including acetone, acetic acid, and water, was analyzed for apparent diffusion coefficient (ADC) based on SPLICE and for diffusion-related coefficient (DRC) based on PSIF. The ADCs based on SPLICE were 4.36±0.89 x 10 -3 mm 2 /sec, 1.25±0.04 x 10 -3 mm 2 /sec, and 2.35±0.04 x 10 -3 mm 2 /sec, and the DRCs based on PSIF were 0.353±0.25, 0.178±0.07, and 0.273±0.018 for acetone, acetic acid, and water, respectively. These calculated ADCs based on SPLICE were well correlated with known diffusion coefficients, showing a correlation coefficient of 0.995. Second, PSIF and SPLICE were applied to the CNS. The advantage of PSIF and SPLICE was that susceptibility artifacts were reduced in the images of spinal cord and brain stem. PSIF was especially useful for diffusion MR imaging in the spinal cord. The disadvantage of SPLICE was the decreased SN ratio. We conclude that PSIF or SPLICE may be helpful when EPI diffusion MR imaging is insufficient. (author)

  12. Diffuse-light absorption spectroscopy by fiber optics for detecting and quantifying the adulteration of extra virgin olive oil

    Science.gov (United States)

    Mignani, A. G.; Ciaccheri, L.; Ottevaere, H.; Thienpont, H.; Conte, L.; Marega, M.; Cichelli, A.; Attilio, C.; Cimato, A.

    2010-09-01

    A fiber optic setup for diffuse-light absorption spectroscopy in the wide 400-1700 nm spectral range is experimented for detecting and quantifying the adulteration of extra virgin olive oil caused by lower-grade olive oils. Absorption measurements provide spectral fingerprints of authentic and adulterated oils. A multivariate processing of spectroscopic data is applied for discriminating the type of adulterant and for predicting its fraction.

  13. Single-shot spiral imaging enabled by an expanded encoding model: Demonstration in diffusion MRI.

    Science.gov (United States)

    Wilm, Bertram J; Barmet, Christoph; Gross, Simon; Kasper, Lars; Vannesjo, S Johanna; Haeberlin, Max; Dietrich, Benjamin E; Brunner, David O; Schmid, Thomas; Pruessmann, Klaas P

    2017-01-01

    The purpose of this work was to improve the quality of single-shot spiral MRI and demonstrate its application for diffusion-weighted imaging. Image formation is based on an expanded encoding model that accounts for dynamic magnetic fields up to third order in space, nonuniform static B 0 , and coil sensitivity encoding. The encoding model is determined by B 0 mapping, sensitivity mapping, and concurrent field monitoring. Reconstruction is performed by iterative inversion of the expanded signal equations. Diffusion-tensor imaging with single-shot spiral readouts is performed in a phantom and in vivo, using a clinical 3T instrument. Image quality is assessed in terms of artefact levels, image congruence, and the influence of the different encoding factors. Using the full encoding model, diffusion-weighted single-shot spiral imaging of high quality is accomplished both in vitro and in vivo. Accounting for actual field dynamics, including higher orders, is found to be critical to suppress blurring, aliasing, and distortion. Enhanced image congruence permitted data fusion and diffusion tensor analysis without coregistration. Use of an expanded signal model largely overcomes the traditional vulnerability of spiral imaging with long readouts. It renders single-shot spirals competitive with echo-planar readouts and thus deploys shorter echo times and superior readout efficiency for diffusion imaging and further prospective applications. Magn Reson Med 77:83-91, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  14. Diffusion tensor mode in imaging of intracranial epidermoid cysts: one step ahead of fractional anisotropy

    International Nuclear Information System (INIS)

    Jolapara, Milan; Kesavadas, Chandrasekharan; Saini, Jitender; Patro, Satya Narayan; Gupta, Arun Kumar; Kapilamoorthy, Tirur Raman; Bodhey, Narendra; Radhakrishnan, V.V.

    2009-01-01

    The signal characteristics of an epidermoid on T2-weighted imaging have been attributed to the presence of increased water content within the tumor. In this study, we explore the utility of diffusion tensor imaging (DTI) and diffusion tensor metrics (DTM) in knowing the microstructural anatomy of epidermoid cysts. DTI was performed in ten patients with epidermoid cysts. Directionally averaged mean diffusivity (D av ), exponential diffusion, and DTM-like fractional anisotropy (FA), diffusion tensor mode (mode), linear (CL), planar (CP), and spherical (CS) anisotropy were measured from the tumor as well as from the normal-looking white matter. Epidermoid cysts showed high FA. However, D av and exponential diffusion values did not show any restriction of diffusion. Diffusion tensor mode values were near -1, and CP values were high within the tumor. This suggested preferential diffusion of water molecules along a two-dimensional geometry (plane) in epidermoid cysts, which could be attributed to the parallel-layered arrangement of keratin filaments and flakes within these tumors. Thus, advanced imaging modalities like DTI with DTM can provide information regarding the microstructural anatomy of the epidermoid cysts. (orig.)

  15. Tensor Based Representation and Analysis of Diffusion-Weighted Magnetic Resonance Images

    Science.gov (United States)

    Barmpoutis, Angelos

    2009-01-01

    Cartesian tensor bases have been widely used to model spherical functions. In medical imaging, tensors of various orders can approximate the diffusivity function at each voxel of a diffusion-weighted MRI data set. This approximation produces tensor-valued datasets that contain information about the underlying local structure of the scanned tissue.…

  16. The role of diffusion tensor imaging in brain tumor surgery : A review of the literature

    NARCIS (Netherlands)

    Potgieser, Adriaan R. E.; Wagemakers, Michiel; van Hulzen, Arjen L. J.; de Jong, Bauke M.; Hoving, Eelco W.; Groen, Rob J. M.

    Diffusion tensor imaging (DTI) is a recent technique that utilizes diffusion of water molecules to make assumptions about white matter tract architecture of the brain. Early on, neurosurgeons recognized its potential value in neurosurgical planning, as it is the only technique that offers the

  17. Diffusion-tensor MR imaging of gray and white matter development during normal human brain maturation.

    Science.gov (United States)

    Mukherjee, Pratik; Miller, Jeffrey H; Shimony, Joshua S; Philip, Joseph V; Nehra, Deepika; Snyder, Abraham Z; Conturo, Thomas E; Neil, Jeffrey J; McKinstry, Robert C

    2002-10-01

    Conventional MR imaging findings of human brain development are thought to result from decreasing water content, increasing macromolecular concentration, and myelination. We use diffusion-tensor MR imaging to test theoretical models that incorporate hypotheses regarding how these maturational processes influence water diffusion in developing gray and white matter. Experimental data were derived from diffusion-tensor imaging of 167 participants, ages 31 gestational weeks to 11 postnatal years. An isotropic diffusion model was applied to the gray matter of the basal ganglia and thalamus. A model that assumes changes in the magnitude of diffusion while maintaining cylindrically symmetric anisotropy was applied to the white matter of the corpus callosum and internal capsule. Deviations of the diffusion tensor from the ideal model predictions, due to measurement noise, were estimated by using Monte Carlo simulations. Developing gray matter of the basal ganglia and developing white matter of the internal capsule and corpus callosum largely conformed to theory, with only small departures from model predictions in older children. However, data from the thalamus substantially diverged from predicted values, with progressively larger deviations from the model with increasing participant age. Changes in water diffusion during maturation of central gray and white matter structures can largely be explained by theoretical models incorporating simple assumptions regarding the influence of brain water content and myelination, although deviations from theory increase as the brain matures. Diffusion-tensor MR imaging is a powerful method for studying the process of brain development, with both scientific and clinical applications.

  18. Adaptive distance learning scheme for diffusion tensor imaging using kernel target alignment

    NARCIS (Netherlands)

    Rodrigues, P.R.; Vilanova, A.; Twellmann, T.; Haar Romenij, ter B.M.; Alexander, D.; Gee, J.; Whitaker, R.

    2008-01-01

    In segmentation techniques for Diffusion Tensor Imaging (DTI) data, the similarity of diffusion tensors must be assessed for partitioning data into regions which are homogeneous in terms of tensor characteristics. Various distance measures have been proposed in literature for analysing the

  19. Cerebral Effects of Targeted Temperature Management Methods Assessed by Diffusion-Weighted Magnetic Resonance Imaging

    DEFF Research Database (Denmark)

    Grejs, Anders Morten; Gjedsted, Jakob; Pedersen, Michael

    2016-01-01

    The aim of this randomized porcine study was to compare surface targeted temperature management (TTM) to endovascular TTM evaluated by cerebral diffusion-weighted magnetic resonance imaging (MRI): apparent diffusion coefficient (ADC), and by intracerebral/intramuscular microdialysis. It is well k...

  20. Role of magnetic resonance diffusion imaging and apparent diffusion coefficient values in the evaluation of spinal tuberculosis in Indian patients

    International Nuclear Information System (INIS)

    Palle, Lalitha; Reddy, MCH Balaji; Reddy, K Jagannath

    2010-01-01

    To define a range of apparent diffusion coefficient values in spinal tuberculosis and to evaluate the sensitivity of diffusion-weighted magnetic resonance imaging (DW-MRI) and apparent diffusion coefficient values in patients of spinal tuberculosis. This study was conducted over a period of 20 months and included 110 patients with a total of 230 vertebral bodies. The study was performed in two parts. The first part included all patients of known tuberculosis and patients with classical features of tuberculosis. The second part included patients with spinal pathology of indeterminate etiology. All the patients underwent a routine MRI examination along with diffusion sequences. The apparent diffusion coefficient (ADC) values were calculated from all the involved vertebral bodies. The mean ADC value of affected vertebrae in first part of the study was found to be 1.4 ± 0.20 × 10 −3 mm 2 /s. This ADC value was then applied to patients in the second part of study in order to determine its ability in predicting tuberculosis. This range of ADC values was significantly different from the mean ADC values of normal vertebrae and those with metastatic involvement. However, there was an overlap of ADC values in a few tuberculous vertebrae with the ADC values in metastatic vertebrae. We found that DW-MRI and ADC values may help in the differentiation of spinal tuberculosis from other lesions of similar appearance. However, an overlap of ADC values was noted with those of metastatic vertebrae. Therefore diffusion imaging and ADC values must always be interpreted in association with clinical history and routine MRI findings and not in isolation

  1. Understanding the Cryosphere of Europa Using Imaging Spectroscopy

    Science.gov (United States)

    Blaney, D. L.; Green, R. O.; Hibbitts, C.; Clark, R. N.; Dalton, J. B.; Davies, A. G.; Langevin, Y.; Hedman, M.; Lunine, J. I.; McCord, T. B.; Murchie, S. L.; Paranicas, C.; Seelos, F. P.; Soderblom, J. M.; Diniega, S.

    2017-12-01

    Europa's surface expresses a complex interplay of geologic processes driven by the ocean beneath the cryosphere that are subsequently modified by the Jovian environment once exposed on the surface. Several recent Earth-based observations of Europa's tenuous atmosphere suggest that there may in fact be active plumes [1,2,3]. However, the frequency and the duration of activity at any specific location cannot be precisely determined by these observations, but could be with spacecraft observations. For instance, recently active areas on Europa from plumes or other processes may result in distinctive spectral signatures on the surface. Possible spectral signatures that may indicate recent activity include: differences in ice grain size or ice crystallinity; the lack of radiolytic signatures (e.g. a deficit in species due to implantation, radiation darkening of salts, degradation of organic compounds); and thermal anomalies. The Mapping Imaging Spectrometer for Europa (MISE) on NASA's Europa Clipper Mission will be able to map these species thus enabling the identification of these deposits and other young and/or least processed areas. These signatures may also enable a relative geochronology for Europa to be developed. For example, recent work by Proctor et al [4] finds that bands of different stratigraphic ages have different spectral features potentially due to radiatio