bluuebunny/crossref_metadata_2025_split huggingface dataset:
Map‐ISODATA demarcates regional response to combination rt‐PA and 7E3 F(ab′)2 treatment of embolic stroke in the rat
Authors: Li Lian , Jiang Quan , Ding Guangliang , Zhang Li , Zhang Zheng Gang , Ewing James R. , Knight Robert A. , Kapke Alissa , Soltanian‐Zadeh Hamid , Chopp Michael 
Published: May 2005

AbstractPurposeTo investigate the ability of map‐ISODATA (Iterative Self‐Organizing Data Analysis Technique) to classify the different categories of ischemic damage in the lesion and to evaluate a combined (thrombolysis plus antiplatelet) treatment efficacy in an embolic stroke of rat.Materials and MethodsRats subjected to embolic stroke with (N = 12) and without (N = 10) rt‐PA and 7E3 F(ab′)2 treatment (4 hours after embolization) were followed (at 2, 24, and 48 hours post‐MCAO) with magnetic resonance imaging (MRI) using T1, T2, and apparent diffusion coefficient of water (ADCw). ISODATA was computed from T1, T2, and ADCw maps. The signatures characterized by the map‐ISODATA were compared with histological quantitative evaluation and were employed to demarcate the specific regions in the lesion.ResultsThe signature described by map‐ISODATA is highly correlated with the degree of tissue damage in the lesion and can distinguish the severity of ischemic tissue injury. Based upon map‐ISODATA, ischemic lesion area can be divided into three specific regions, each characterized by a distinct evolution of injury and treatment response. The combined treatment significantly reduces the lesion size between 24 and 48 hours and improves the outcome 48 hours post‐MCAO compared with the control group.ConclusionMap‐ISODATA provides an accurate means to identify lesion area, to distinguish ischemic damage, and to detect treatment response. 7E3 F(ab′)2 extends the rt‐PA treatment window to at least four hours after the onset of embolic stroke of rat. J. Magn. Reson. Imaging 2005;21:726–734. © 2005 Wiley‐Liss, Inc.
T1 mapping of the entire lung parenchyma: Influence of the respiratory phase in healthy individuals
Authors: Stadler Alfred , Jakob Peter M. , Griswold Mark , Barth Markus , Bankier Alexander A. 
Published: May 2005

AbstractPurposeTo determine the effect of respiratory phase on the T1 values of the entire lung.Materials and MethodsWe calculated T1 relaxation time on a pixel‐by‐pixel analysis of a series of Snapshot FLASH tomograms acquired after a single inversion pulse. Two sets of coronal T1 maps were acquired, one in full suspended inspiration and one in suspended expiration.ResultsThe average of the mean T1 values over the entire lung in inspiration was 1199 ± 117 msec, the average of the mean T1 values in expiration was 1333 ± 167 msec. This difference was statistically significant, at P = 0.005. In inspiration the average coefficient of variation was 182 ± 56 msec, in expiration it was 153 ± 41 msec. This difference was not statistically significant.ConclusionT1 measurements of the entire lung are feasible. Our findings underline the need for a close monitoring of the inspirational status during MR examinations of the thorax, notably when T1 measurements of the lung are performed. J. Magn. Reson. Imaging 2005;21:759–764. © 2005 Wiley‐Liss, Inc.
Intratumor heterogeneity in blood perfusion in orthotopic human melanoma xenografts assessed by dynamic contrast‐enhanced magnetic resonance imaging
Authors: Gaustad Jon‐Vidar , Benjaminsen Ilana C. , Graff Bjørn A. , Brurberg Kjetil G. , Ruud Else‐Beate M. , Rofstad Einar K. 
Published: May 2005

AbstractPurposeTo determine the intratumor heterogeneity in blood perfusion of orthotopic human melanoma xenografts by use of gadopentetate dimeglumine (Gd‐DTPA)‐based dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI).Materials and MethodsOrthotopic xenografts of an amelanotic human melanoma cell line (A‐07) were scanned sagittally, coronally, and axially in three subsequent DCE‐MRI sessions, using spoiled gradient recalled sequences, a voxel size of 0.31 × 0.62 × 2.0 mm3, and an interleaving acquisition method to avoid slice gaps. Tumor images of E · F (E is initial extraction fraction and F is perfusion) were produced by subjecting the DCE‐MRI data to Kety analysis. E · F was used as a parameter for tumor blood perfusion, since E for Gd‐DTPA is close to unity in A‐07 tumors.ResultsAll A‐07 tumors subjected to investigation showed anisotropic radial heterogeneity in blood perfusion. The blood perfusion was low in the center of the tumors and increased toward the tumor periphery in the cranial, dorsal, caudal, and ventral directions, but not in the lateral and medial directions. In addition, 9 of 10 tumors showed blood perfusion hot spots in central or nonperipheral regions. The hot spots differed significantly between tumors in size, shape, location, and intensity, and appeared to be governed by stochastic processes. This heterogeneity superimposed the radial heterogeneity, but did not overshadow it in any tumor.ConclusionOrthotopic human melanoma xenografts show significant intratumor heterogeneity in blood perfusion. This heterogeneity is made up of two distinctly different components, one stochastic and one nonstochastic radial component. The radial component is anisotropic and dominant and is superimposed by the stochastic component. J. Magn. Reson. Imaging 2005;21:792–800. © 2005 Wiley‐Liss, Inc.
Quantitative perfusion measurements using pulsed arterial spin labeling: Effects of large region‐of‐interest analysis
Authors: Figueiredo Patrícia M. , Clare Stuart , Jezzard Peter 
Published: May 2005

AbstractPurposeTo study arterial spin labeling (ASL) MRI techniques and to investigate various problematic issues that still hinder the accurate and robust quantitative analysis of ASL data.Materials and MethodsA pulsed‐ASL (PASL) sequence was implemented on a 3‐T imaging system and a protocol was developed for the measurement of perfusion based on fitting to a standard kinetic model. Both numerical simulations and multi‐inversion time MRI data were analyzed. The effect of fitting a kinetic curve to a large region of interest (ROI) with a distribution of arterial transit times was compared to a pixel‐by‐pixel (PBP) method.ResultsIt was found that a significant underestimation of perfusion of approximately 17 ± 6% (P < 0.001) occurs in gray matter, when comparing an ROI with a PBP analysis over a group of 12 healthy subjects.ConclusionAnalysis of ASL data based on a large ROI may suffer from inaccuracies arising from a distribution of transit times, implying that averaging of ASL kinetic data over such regions should therefore be avoided. When possible, a PBP fit should be performed. J. Magn. Reson. Imaging 2005;21:676–682. © 2005 Wiley‐Liss, Inc.
Tissue edema does not change gadolinium‐diethylenetriamine pentaacetic acid (Gd‐DTPA)‐enhanced T1 relaxation times of viable myocardium
Authors: Li Gang , Xiang Bo , Dai Guangping , Shaw Anthony , Liu Hongyu , Yang Baofeng , Jackson Mike , Deslauriers Roxanne , Tian Ganghong 
Published: May 2005

AbstractPurposeTo determine whether tissue edema changes gadolinium‐diethylenetriamine pentaacetic acid (Gd‐DTPA)‐enhanced T1 relaxation times of the viable myocardium.Materials and MethodsA total of 16 isolated pig hearts were divided into four groups (N = 4/group) and perfused in a Langendorff apparatus. Gd‐DTPA was injected into the aortic perfusion line. Tissue edema was then induced by two hours of simultaneous arterial/venous perfusion (SAVP). Myocardial water content and T1 relaxation times were monitored throughout SAVP. The volumes of the extracellular and intracellular compartments were assessed using 31P MRS‐detectable markers, phenylphosphonic acid (PPA) and dimethyl methylphosphonate (DMMP).ResultsTissue water content in both viable and infarcted myocardium increased significantly during two‐hour SAVP. However, Gd‐DTPA‐enhanced T1 relaxation times of the viable myocardium remained relatively unchanged. Infarcted myocardium, on the other hand, exhibited significant T1 shortening during SAVP. Furthermore, SAVP resulted in significant expansions of both extracellular and intracellular compartments, but the ratio of the volumes of the two compartments remained relatively constant.ConclusionTissue edema in the viable myocardium does not increase the relative distribution volume of the contrast agent. As a result, edema does not change Gd‐DTPA‐enhanced T1 relaxation times of the viable myocardium. J. Magn. Reson. Imaging 2005;21:744–751. Published 2005 Wiley‐Liss, Inc.
Relationship between contrast enhancement on fluid‐attenuated inversion recovery MR sequences and signal intensity on T2‐weighted MR images: Visual evaluation of brain tumors
Authors: Kubota Takao , Yamada Kei , Kizu Osamu , Hirota Tatsuya , Ito Hirotoshi , Ishihara Kiyoshi , Nishimura Tsunehiko 
Published: May 2005

AbstractPurposeTo investigate the relationship between the degree of contrast enhancement in fluid‐attenuated inversion recovery (FLAIR) sequences and tumor signal intensity on T2‐weighted images.Materials and MethodsA total of 96 patients suspected of having brain tumors were examined by MR imaging, and whenever a brain tumor with an enhancing part larger than the slice thickness was demonstrated on postcontrast T1‐weighted images, postcontrast FLAIR images were additionally acquired. The tumor signal intensity on the T2‐weighted images was visually classified as follows: equal or lower compared with normal cerebral cortex (group 1), higher than normal cortex (group 2), and as high as cerebrospinal fluid (CSF) (group 3). When a lesion contained several parts with different signal intensities on T2‐weighted images, we assessed each part separately. In each group, we visually compared pre‐ and postcontrast FLAIR images and assessed whether tumor contrast enhancement was present. When contrast enhancement was present on FLAIR sequence, the degree of contrast enhancement in T1‐weighted and FLAIR sequences was visually compared.ResultsPostcontrast T1‐weighted images showed 46 enhancing lesions, including 48 parts, in 31 MR examinations. FLAIR images of the lesion‐parts in group 1 (N = 18) did not show significant contrast enhancement. In group 2 (N = 12), all the parts were enhanced in FLAIR sequences, and three parts were enhanced more clearly in the FLAIR sequences than in the T1‐weighted sequences. In group 3 (N = 18), all the parts were enhanced equally or more clearly in the FLAIR sequences than in the T1‐weighted sequences.ConclusionThe signal intensity in FLAIR sequences is largely influenced by both T1 and T2 relaxation time; there is a close relationship between the signal intensity of brain tumors on T2‐weighted images and the degree of contrast enhancement on FLAIR sequences. When tumors have higher signal intensity than normal cortex on T2‐weighted images, additional postcontrast FLAIR imaging may improve their depiction. J. Magn. Reson. Imaging 2005;21:694–700. © 2005 Wiley‐Liss, Inc.
Navigator‐gated three‐dimensional MR angiography of the pulmonary arteries using steady‐state free precession
Authors: Hui Benjamin K. , Noga Michelle L. , Gan Kenman D. , Wilman Alan H. 
Published: May 2005

AbstractPurposeTo assess the quality of a navigator‐gated, free breathing, steady‐state free precession (SSFP) technique in comparison to a single breathhold for pulmonary artery imaging in normal volunteers.Materials and MethodsSagittal sections of the left pulmonary arteries of 10 volunteers were obtained with a three‐dimensional SSFP sequence using both a single breathhold of 30 seconds and a navigator‐gated version of the same sequence. The images were compared and rated by a blinded cardiovascular radiologist for image quality, sharpness, and artifact.ResultsOn a scale ranging from −2 to 2, in which positive numbers denote that the navigator method was favorable compared to the single breathhold method, image quality was rated 0.7 ± 1.4, sharpness 0.6 ± 1.5, and artifact 0.1 ± 1.4. Thus, there was no statistical difference between the two methods.ConclusionThe navigator‐gated SSFP sequence is able to acquire images equal in quality to the breathhold sequence. This may be of clinical importance for pulmonary imaging in patients who are unable to sustain a long breathhold. J. Magn. Reson. Imaging 2005;21:831–835. © 2005 Wiley‐Liss, Inc.
Quantitative apparent diffusion coefficients and T2 relaxation times in characterizing contrast enhancing brain tumors and regions of peritumoral edema
Authors: Oh Joonmi , Cha Soonmee , Aiken Ashley H. , Han Eric T. , Crane Jason C. , Stainsby Jeffrey A. , Wright Graham A. , Dillon William P. , Nelson Sarah J. 
Published: May 2005

AbstractPurposeTo investigate the potential value and relationship of in vivo quantification of apparent diffusion coefficients (ADCs) and T2 relaxation times for characterizing brain tumor cellularity and tumor‐related edema.Materials and MethodsA total of 26 patients with newly diagnosed gliomas, meningiomas, or metastases underwent diffusion‐weighted and six‐echo multisection T2‐preparation imaging. Regions of interest (ROIs) were drawn on conventional MR images to include tumor (as defined by contrast agent enhancement) and immediate and peripheral edema. Areas of necrosis were excluded. Median values of ADCs and T2 in the ROIs were calculated.ResultsADCs for gliomas were similar to those for meningiomas or metastases in all regions. Tumor T2 values for gliomas (159.5 ± 30.6 msec) were significantly higher than those for meningiomas or metastases (125.0 ± 31.1 msec; P = 0.005). Immediate‐edema T2 values for meningiomas or metastases (226.0 ± 44.1 msec) were significantly higher than those for gliomas (203.5 ± 32.8 msec; P = 0.033). Peripheral‐edema T2 values for gliomas (219.5 ± 41.9 msec) were similar to those for meningiomas or metastases (202.5 ± 26.5 msec; P = 0.377). Both immediate‐ and peritumoral‐edema ADCs and T2 values were significantly higher than those in tumor for both tumor types. ADCs and T2 values from all regions correlated significantly for gliomas (r = 0.95; P < 0.0001) and for meningiomas or metastases (r = 0.81; P < 0.0001).ConclusionThe higher immediate‐edema T2 values for nonglial tumors than for gliomas suggest tumor‐related edema (vasogenic vs. infiltrated) can be further characterized by using T2 values. There were significant correlations between ADC and T2 values. J. Magn. Reson. Imaging 2005;21:701–708. © 2005 Wiley‐Liss, Inc.
The magnetic resonance Matas test: Feasibility and comparison with the conventional intraarterial balloon test occlusion with SPECT perfusion imaging
Authors: Hori Masaaki , Okubo Toshiyuki , Aoki Shigeki , Ishigame Keiichi , Araki Tsutomu , Nukui Hideaki 
Published: May 2005

AbstractPurposeTo evaluate a new MR Matas test that uses a form of contrast‐enhanced MR angiography (MRA) with temporary manual occlusion of the common carotid artery whose internal carotid artery (ICA) is to be permanently sacrificed.Materials and MethodsThe MR Matas test was performed on eight patients using an open type MR imager (Signa Profile 0.2 Tesla ver. 7.5, GE‐YMS, Tokyo, Japan). Conventional balloon occlusion Matas test and single‐photon emission computed tomography (SPECT) of the brain were performed in all cases within a week before or after the MR Matas test.ResultsThe MR Matas test was successful in all eight patients without any complications. The image quality of the MR Matas test was generally sufficient to confirm cross‐flow from the patent side to the occluded side in comparison with selective intraarterial digital subtraction angiography (IADSA) except in one case.ConclusionBrain perfusion information using MR Matas test is comparable to brain SPECT. J. Magn. Reson. Imaging 2005;21:709–714. © 2005 Wiley‐Liss, Inc.
Microneurography of human median nerve
Authors: Bilgen Mehmet , Heddings Archie , Al‐Hafez Baraa , Hasan Wohaib , McIff Terence , Toby Bruce , Nudo Randolph , Brooks William M. 
Published: May 2005

AbstractPurposeTo examine the possibility of performing high‐resolution MRI (microneurography) on peripheral nerves.Materials and MethodsA specific radio frequency (RF) coil was developed to probe the human median nerve at a magnetic field strength of 9.4 T and tested on three excised samples by acquiring microneurograms.ResultsThe microneurograms revealed neuronal tissue constituents at subfascicular level. The contrast features on proton‐density and T1‐ and T2‐weighted images were described and compared. The microscopic water movement was quantified using diffusion weighting parallel and orthogonal to the neuronal fiber orientation. The characteristics of anisotropic diffusion in the median nerve were comparable to those reported from other biological tissues (white matter and kidney).ConclusionThe results overall suggest that microneurography might provide new noninvasive insights into microscopic gross anatomy of the peripheral nerve, injury evaluation, and efficacy of repair, although the feasibility at current clinically relevant field strengths is yet to be determined. J. Magn. Reson. Imaging 2005;21:826–830. © 2005 Wiley‐Liss, Inc.
Application of refocused steady‐state free‐precession methods at 1.5 and 3 T to in vivo high‐resolution MRI of trabecular bone: Simulations and experiments
Authors: Banerjee Suchandrima , Han Eric T. , Krug Roland , Newitt David C. , Majumdar Sharmila 
Published: May 2005

AbstractPurposeTo evaluate the potential of fully‐balanced steady‐state free‐precession (SSFP) sequences in in vivo high‐resolution (HR) MRI of trabecular bone at field strengths of 1.5 and 3 T by simulation and experimental methods.Materials and MethodsUsing simulation studies, refocused SSFP acquisition was optimized for our imaging purposes with a focus on signal‐to‐noise ratio (SNR) and SNR efficiency. The signal behavior in trabecular bone was estimated using a magnetostatic model of the trabecular bone and marrow. Eight normal volunteers were imaged at the proximal femur, calcaneus, and the distal tibia on a GE Signa scanner at 1.5 and at 3 T with an optimized single‐acquisition SSFP sequence (three‐dimensional FIESTA) and an optimized multiple‐acquisition SSFP sequence (three‐dimensional FIESTA‐c). Images were also acquired with a fast gradient echo (FGRE) sequence for evaluation of the SNR performance of SSFP methods.ResultsRefocused SSFP images outperformed FGRE acquisitions in both SNR and SNR efficiency at both field strengths. At 3 T, susceptibility effects were visible in FIESTA and FGRE images and much reduced in FIESTA‐c images. The magnitude of SNR boost at 3 T was closely predicted by simulations.ConclusionSingle‐acquisition SSFP (at 1.5 T) and multiple‐acquisition SSFP (at 3 T) hold great potential for HR‐MRI of trabecular bone. J. Magn. Reson. Imaging 2005;21:818–825. © 2005 Wiley‐Liss, Inc.
Efficacy of the 1.5 millisecond pulse‐duration, 585 nm, pulsed‐dye laser for treating port‐wine stains
Authors: Bernstein Eric F. , Brown Douglas B. 
Published: May 2005

AbstractBackground and ObjectivesSome reports have suggested that 1.5‐millisecond pulse‐duration pulsed‐dye lasers (PDLs) may have increased efficacy in treating port‐wine stains (PWSs) as compared to previous generation lasers.We study the efficacy of the 1.5‐millisecond pulse‐duration PDL for treating PWSs.Study Design/Materials and MethodsWe treated 104 areas of involvement by PWSs in 95 subjects with the 1.5‐millisecond pulse‐duration PDL. Subjective and objective measures of improvement were utilized. Twenty‐one of these PWSs had failed treatment with earlier generation PDLs.ResultsPWSs previously refractory to the shorter pulse duration lasers responded well to treatment, as did PWSs not previously treated with any laser.ConclusionsThe 1.5‐millisecond pulse‐duration PDL is effective for treating PWSs and may offer improved efficacy over shorter pulse‐duration lasers. © 2005 Wiley‐Liss, Inc.
Optimal timing for in vivo 1H‐MR spectroscopic imaging of the human prostate at 3T
Authors: Scheenen Tom W.J. , Gambarota Giulio , Weiland Elisabeth , Klomp Dennis W.J. , Fütterer Jurgen J. , Barentsz Jelle O. , Heerschap Arend 
Published: May 2005

AbstractProton MR spectroscopic imaging (1H‐MRSI) of the human prostate, which has an interesting clinical potential, may be improved by increasing the magnetic field strength from 1.5T to 3T. Both theoretical and practical considerations are necessary to optimize the pulse timing for spectroscopic imaging of the human prostate at 3T. For in vivo detection of the strongly coupled spin system of citrate, not only should the spectral shape of the signal be easy to identify, but the timing used should produce MR signals at reasonably short echo times (TEs). In this study the spectral shape of the methylene protons of citrate was simulated with density matrix calculations and checked with phantom measurements. Different calculated optimal spectral shapes were measured in patients with prostate cancer with a 2D spectroscopic imaging sequence. T1 and T2 relaxation times were calculated for citrate and choline, the two major metabolites of interest in the prostate. We conclude that the optimum timing for in vivo point‐resolved spectroscopy (PRESS) imaging at 3T is an interpulse timing sequence of 90° ‐ 25 ms ‐ 180° ‐ 37.5 ms ‐ 180° ‐ 12.5 ms ‐ echo. A short repetition time (TR) of 750 ms partially saturates choline signals, but increases the SNR per unit time for citrate, and accommodates a maximum number of weighted averages of an elliptically sampled k‐space for accurate localization and minimal contamination of the individual spectra. This is illustrated by means of a 3D spectroscopic imaging experiment in a complete prostate in vivo. Magn Reson Med 53:1268–1274, 2005. © 2005 Wiley‐Liss, Inc.
Magnetic resonance angiography of rat spinal cord at 9.4 T: A feasibility study
Authors: Bilgen Mehmet , Al‐Hafez Baraa , He Yong‐Yue , Brooks William M. 
Published: May 2005

AbstractIn this study we investigated the feasibility of performing 3D time‐of‐flight magnetic resonance angiography to remotely image the arteries of rat spinal cord. Using a custom‐designed implantable radiofrequency coil, we acquired angiograms from normal and injured cords. The potential of the approach was evaluated in terms of longitudinally monitoring the vascular reorganization of spinal cord following an injury. Magn Reson Med 53:1459–1461, 2005. © 2005 Wiley‐Liss, Inc.
In vivo detection of cortical GABA turnover from intravenously infused [1‐13C]D‐glucose
Authors: Yang Jehoon , Li Charles Q. , Shen Jun 
Published: May 2005

AbstractIn this study [2‐13C] γ‐aminobutyric acid (GABA) was spectrally resolved in vivo and detected simultaneously with [4‐13C]glutamate (Glu) and [4‐13C]glutamine (Gln) in the proton spectra obtained from a localized 40 μL voxel in rat neocortex with the use of an adiabatic 1H‐observed, 13C‐edited (POCE) spectroscopy method and an 89‐mm‐bore vertical 11.7 Tesla microimager. The time‐resolved kinetics of 13C label incorporation from intravenously infused [1‐13C]glucose into [4‐13C]Glu, [4‐13C]Gln, and [2‐13C]GABA were measured after acute administration of gabaculine, a potent and specific inhibitor of GABA‐transaminase. In contrast to previous observations of a rapid turnover of [2‐13C]GABA from [1‐13C]glucose in intact rat brain, the rate of 13C incorporation from [1‐13C]glucose into [2‐13C]GABA in the gabaculine‐treated rats was found to be significantly reduced as a result of the blockade of the GABA shunt. Magn Reson Med 53:1258–1267, 2005. Published 2005 Wiley‐Liss, Inc.