bluuebunny/crossref_metadata_2025_split huggingface dataset:
MRI tissue characterization of experimental cerebral ischemia in rat
Authors: Soltanian‐Zadeh Hamid , Pasnoor Mamatha , Hammoud Rabih , Jacobs Michael A. , Patel Suresh C. , Mitsias Panayiotis D. , Knight Robert A. , Zheng Zhang G. , Lu Mei , Chopp Michael 
Published: March 2003

AbstractPurposeTo extend the ISODATA image segmentation method to characterize tissue damage in stroke, by generating an MRI score for each tissue that corresponds to its histological damage.Materials and MethodsAfter preprocessing and segmentation (using ISODATA clustering), the proposed method scores tissue regions between 1 and 100. Score 1 is assigned to normal brain matter (white or gray matter), and score 100 to cerebrospinal fluid (CSF). Lesion zones are assigned a score based on their relative levels of similarities to normal brain matter and CSF. To evaluate the method, 15 rats were imaged by a 7T MRI system at one of three time points (acute, subacute, chronic) after MCA occlusion. Then they were killed and their brains were sliced and prepared for histological studies. MRI of two or three slices of each rat brain (using two DWI (b = 400, b = 800), one PDWI, one T2WI, and one T1WI) was performed, and an MRI score between 1 and 100 was determined for each region. Segmented regions were mapped onto the histology images and scored on a scale of 1–10 by an experienced pathologist. The MRI scores were validated by comparison with histology scores. To this end, correlation coefficients between the two scores (MRI and histology) were determined.ResultsExperimental results showed excellent correlations between MRI and histology scores at different time points. Depending on the reference tissue (gray matter or white matter) used in the standardization, the correlation coefficients ranged from 0.73 (P < 0.0001) to 0.78 (P < 0.0001) using the entire dataset, including acute, subacute, and chronic time points. This suggests that the proposed multiparametric approach accurately identified and characterized ischemic tissue in a rat model of cerebral ischemia at different stages of stroke evolution.ConclusionThe proposed approach scores tissue regions and characterizes them using unsupervised clustering and multiparametric image analysis techniques. The method can be used for a variety of applications in the field of computer‐aided diagnosis and treatment, including evaluation of response to treatment. For example, volume changes for different zones of the lesion over time (e.g., tissue recovery) can be evaluated. J. Magn. Reson. Imaging 2003;17:398–409. © 2003 Wiley‐Liss, Inc.
Dynamic MRI of breast hardness following radiation treatment
Authors: Padhani Anwar R. , Yarnold John , Regan Jane , Husband Janet E. 
Published: March 2003

AbstractPurposeTo evaluate functional microvascular characteristics of breast induration several years after radiation treatment using dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) techniques.Materials and MethodsFifteen women with moderate or marked breast induration after surgery and radiotherapy for breast cancer (2–15 years) were examined. Images of the irradiated breast (boost and nonboost sites) on short tau inversion recovery (STIR) and DCE‐MRI sequences were subjectively evaluated for edema and the presence of enhancement and compared to the contralateral normal breast. Quantitative enhancement parameters—percent enhancing pixels, transfer constant (Ktrans), rate constant (kep), leakage space (ve), and maximum contrast medium accumulation (MCMA)—were also compared.ResultsNo tumor recurrence was seen. Fat necrosis was seen in 2/15 cases. Increased parenchymal edema at the electron boost site was seen in 12/14 patients. Greater enhancement in the irradiated breast was seen in 11/14 evaluable patients. Kinetic parameter estimates including Ktrans were similar except for percent enhancing pixels, which was greater in the irradiated breast at both boost and nonboost sites (P = 0.03 and 0.04, respectively). ve and MCMA estimates were greater in breasts with marked induration compared to moderate grades (P = 0.002 and 0.01, respectively).ConclusionParenchymal edema may be an important contributor to palpable induration several years after breast radiotherapy. Increased fluid content may be related to increased numbers of perfused microvessels and/or impaired lymphatic drainage. J. Magn. Reson. Imaging 2003;17:427–434. © 2003 Wiley‐Liss, Inc.
In vivo accuracy of multisequence MR imaging for identifying unstable fibrous caps in advanced human carotid plaques
Authors: Mitsumori Lee M. , Hatsukami Thomas S. , Ferguson Marina S. , Kerwin William S. , Cai Jianming , Yuan Chun 
Published: March 2003

AbstractPurposeTo evaluate the in vivo accuracy of a multisequence MRI technique for prospectively identifying one feature of the vulnerable plaque—an unstable fibrous cap—in human carotid atherosclerosis.Materials and MethodsThe carotid arteries of 18 endarterectomy patients were preoperatively imaged in a 1.5T scanner using a multisequence protocol that generated four contrast weightings (3D time of flight (ToF), T1, proton density (PD), and T2) at each slice location. With the use of previously published MR criteria, the images of the vessel wall were first examined for evidence of an unstable fibrous cap. The imaging findings were then correlated with the histology from the surgical specimens.ResultsA blinded review of the MR findings with the histologic state of the fibrous cap revealed that 1) assessing the preoperative appearance of the fibrous cap has a high test sensitivity (0.81) and specificity (0.90) for identifying an unstable cap in vivo; and 2) the availability of different contrast weightings facilitated image interpretation when intimal calcifications or flow artifacts obscured the lumen surface.ConclusionMultisequence MRI can accurately characterize the in vivo state of the fibrous cap. This finding supports the use of these noninvasive techniques to prospectively identify vulnerable plaques. J. Magn. Reson. Imaging 2003;17:410–420. Published 2003 Wiley‐Liss, Inc.
Calibrated magnetic resonance hydrometry: An in vitro study
Authors: Heverhagen Johannes T. , Boehm Dominik , Klose Klaus J. 
Published: March 2003

AbstractPurposeTo demonstrate a quantitative approach to measuring fluid volumes with standard single shot RARE sequences.Materials and MethodsIn phantom experiments, magnetic resonance hydrometry (MRH), in combination with various calibration phantoms (5 mL up to 500 mL) as internal standards, was used to quantify fluid volumes. In total, 16 volume phantoms were investigated with six different calibration phantoms. In addition, noise correction was implemented to correct the quantification results and to avoid the influence of random noise in the image.ResultsAll MR measurements show significant correlations of up to r = 0.99 (P < .05) with the real applied volume in the investigated phantoms. However, measurements of large volumes were more precise with large calibration phantoms. Noise reduction did not change the correlation between measured and real applied volumes, but did reduce the error of the measured volumes. Calibrated magnetic resonance hydrometry (cMRH) is able to quantify volumes of fluid fast and noninvasively. The volumes of the used calibration phantoms have to be at least in the order of magnitude of the volumes that are to be measured.ConclusionIn vitro, cMRH using a single‐shot rapid acquisition with refocused echoes (ssRARE) sequence and calibration phantoms is a fast and accurate method of quantifying steady amounts of fluid. J. Magn. Reson. Imaging 2003;17:472–477. © 2003 Wiley‐Liss, Inc.
Time‐resolved three‐dimensional phase‐contrast MRI
Authors: Markl Michael , Chan Frandics P. , Alley Marcus T. , Wedding Kris L. , Draney Mary T. , Elkins Chris J. , Parker David W. , Wicker Ryan , Taylor Charles A. , Herfkens Robert J. , Pelc Norbert J. 
Published: March 2003

AbstractPurposeTo demonstrate the feasibility of a four‐dimensional phase contrast (PC) technique that permits spatial and temporal coverage of an entire three‐dimensional volume, to quantitatively validate its accuracy against an established time resolved two‐dimensional PC technique to explore advantages of the approach with regard to the four‐dimensional nature of the data.Materials and MethodsTime‐resolved, three‐dimensional anatomical images were generated simultaneously with registered three‐directional velocity vector fields. Improvements compared to prior methods include retrospectively gated and respiratory compensated image acquisition, interleaved flow encoding with freely selectable velocity encoding (venc) along each spatial direction, and flexible trade‐off between temporal resolution and total acquisition time.ResultsThe implementation was validated against established two‐dimensional PC techniques using a well‐defined phantom, and successfully applied in volunteer and patient examinations. Human studies were performed after contrast administration in order to compensate for loss of in‐flow enhancement in the four‐dimensional approach.ConclusionAdvantages of the four‐dimensional approach include the complete spatial and temporal coverage of the cardiovascular region of interest and the ability to obtain high spatial resolution in all three dimensions with higher signal‐to‐noise ratio compared to two‐dimensional methods at the same resolution. In addition, the four‐dimensional nature of the data offers a variety of image processing options, such as magnitude and velocity multi‐planar reformation, three‐directional vector field plots, and velocity profiles mapped onto selected planes of interest. J. Magn. Reson. Imaging 2003;17:499–506. © 2003 Wiley‐Liss, Inc.
Flow‐independent magnetic resonance venography of the calf
Authors: Gallix Benoît P. , Achard‐Lichère Cécile , Dauzat Michel , Bruel Jean‐Michel , Lopez Francois‐Michel 
Published: March 2003

AbstractPurposeTo show that flow‐independent venography that exploit the intrinsic MR properties of blood to isolate vessels from surrounding structures can be used for depiction of peripheral veins and for detection of deep venous thrombosis (DVT).Materials and MethodsSequence and parameters were first determined on a theoretical basis. The sequence was then optimized in volunteers (N = 4) for the depiction of the peripheral venous vessels. Qualitative evaluation of the normal venous anatomy was performed in five volunteers. The feasibility of diagnosing DVT of the calf with this method was evaluated with preliminary clinical studies.ResultsExcellent depiction of the venous anatomy was achieved in all volunteers with the optimized technique. Very small venous structures, such as superficial, muscular, and perforator veins, were clearly depicted because of the high spatial and contrast resolution capacities of the sequences. In all six patients, DVT findings diagnosed by duplex sonography were also seen on MR venography.ConclusionVenous anatomy mapping and detection of lower‐limb DVT appear feasible using flow‐independent MR venograms. J. Magn. Reson. Imaging 2003;17:421–426. © 2003 Wiley‐Liss, Inc.
Tumor vascular architecture and function evaluated by non‐invasive susceptibility MRI methods and immunohistochemistry
Authors: Robinson Simon P. , Rijken Paul F.J.W. , Howe Franklyn A. , McSheehy Paul M.J. , van der Sanden Boudewijn P.J. , Heerschap Arend , Stubbs Marion , van der Kogel Albert J. , Griffiths John R. 
Published: March 2003

AbstractPurposeTo investigate the physiological origins responsible for the varying blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) responses to carbogen (95% O2/5% CO2) breathing observed with different tumor types.Materials and MethodsSusceptibility contrast‐enhanced MRI using the exogenous blood pool contrast agent NC100150 to determine blood volume and vessel size, and immunohistochemical‐derived morphometric parameters, were determined in GH3 prolactinomas and RIF‐1 fibrosarcomas, both grown in mice, which exhibited very different BOLD responses to carbogen.ResultsAdministration of NC100150 increased the R2* and R2 rates of both tumor types, and indicated a significant four‐fold larger blood volume in the GH3 tumor. The ratio ΔR2*/ΔR2 showed that the capillaries in the GH3 were two‐fold larger than those in the RIF‐1, in agreement with morphometric analysis. Carbogen breathing induced a significant 25% decrease in R2* in the GH3 prolactinoma, whereas the response in the RIF‐1 fibrosarcoma was negligible.ConclusionLow blood volume and small vessel size (and hence reduced hematocrit) are two reasons for the lack of R2* change in the RIF‐1 with carbogen breathing. BOLD MRI is sensitive to erythrocyte‐perfused vessels, whereas exogenous contrast agents interrogate the total perfused vascular volume. BOLD MRI, coupled with a carbogen challenge, provides information on functional, hemodynamic tumor vasculature. J. Magn. Reson. Imaging 2003;17:445–454. © 2003 Wiley‐Liss, Inc.
Magnetic resonance microscopy quantifies the disease progression in Marfan syndrome mice
Authors: Itskovich Vitalii V. , Lieb Mark , Aguinaldo Juan Gilberto S. , Samber Daniel D. , Ramirez Francesco , Fayad Zahi A. 
Published: March 2003

AbstractPurposeTo use noninvasive magnetic resonance microscopy (MRM) to examine aneurysmal disease in the mouse model of Marfan syndrome (MFS).Materials and MethodsA total of eight wild‐type (WT) and MFS mice were imaged using MRM; four of them at three different time points over an 8‐week period and the remaining animals were imaged at one time point. The maximal cross‐sectional area of the aorta was measured by manual tracing and by automated means from combined cardiac and respiratory‐gated bright‐blood images. Relationships between aortic size and age and the differences between WT and mutant mice aortic size were established.ResultsMaximal cross‐sectional aortic areas differed significantly (P < 0.05) between WT and mutant mice for all time points, with MFS mice having larger aortic size. There was a positive correlation between aortic size and age in MFS mice (r = 0.80) with a significant increase from the 14th to the 22nd week (P < 0.05).ConclusionMRM detected the differences in aortic size between WT and mutant mice over time, demonstrating a potential for noninvasive technique for the assessment of potential therapies in MFS mice. J. Magn. Reson. Imaging 2003;17:435–439. © 2003 Wiley‐Liss, Inc.
Challenges in dynamic contrast‐enhanced MRI imaging of cervical lymph nodes to detect metastatic disease
Authors: Noworolski Susan M. , Fischbein Nancy J. , Kaplan Michael J. , Lu Ying , Nelson Sarah J. , Carvajal Lucas , Henry Roland G. 
Published: March 2003

AbstractPurposeTo identify and overcome challenges in using dynamic contrast‐enhanced magnetic resonance imaging (MRI) to distinguish tumor from nontumor in the cervical lymph nodes of patients with squamous cell carcinoma of the head and neck.Materials and MethodsSignal‐to‐noise ratio (S/N), motion, node heterogeneity, and tissue normalizations were examined. Twenty‐one patients with squamous cell carcinoma of the head and neck were scanned before a neck dissection (two‐dimensional fast spoiled gradient‐echo: 10 locations/13 seconds). Peak time, peak enhancement, maximum upslope, and washout slope were measured in pathologically confirmed tumor and nontumor nodes and in the submandibular gland and the sternocleidomastoid muscle.ResultsSurface coil arrays provided high coverage and high S/N. Motion averaged 1.1 pixels and was corrected. Large tumor nodes were heterogeneous in their contrast enhancement, while the nontumor nodes were homogeneous. The contrast enhancement parameters were significantly different for all regions except for the submandibular gland compared to the nontumor nodes.ConclusionChallenges of dynamic imaging of cervical lymph nodes were overcome and significant differences were found between the tumor and nontumor nodes, indicating that dynamic imaging is feasible and may aid this patient population. J. Magn. Reson. Imaging 2003;17:455–462. © 2003 Wiley‐Liss, Inc.
Juxtapapillary diverticulum: Findings on MRI
Authors: Balci N. Cem , Noone Tara , Akün Elif , Akinci Ahmet , Klör Hans‐Ulrich 
Published: March 2003

AbstractThe purpose of our study was to describe the imaging findings of juxtapapillary diverticulum on magnetic resonance imaging (MRI). The MRI and magnetic resonance cholangiopancreatography (MRCP) examinations of 14 patients with juxtapapillary diverticula that were diagnosed on endoscopic retrograde cholangiopancreatography (ERCP) (N = 8) or endoscopy (N = 6) were retrospectively evaluated. T1‐weighted spoiled gradient‐echo, T2‐weighted half Fourier single shot fast spin‐echo (HASTE), and T2‐weighted True FISP (fast imaging with steady state precession) images and thin‐slice MRCP images were obtained on all patients. In five patients, diluted gadolinium DPTA (1/100) was used as an oral contrast. T2‐weighted True FISP and HASTE images demonstrated air‐fluid levels within all diverticula. Hyperintense oral contrast on T1‐weighted spoiled gradient‐echo images aided detection of the smaller diverticula. MRCP images obtained in the coronal plane best demonstrated the relationship of the diverticula to the papilla. MRI with the use of HASTE, True FISP, and oral contrast‐enhanced T1‐weighted sequences was able to depict juxtapapillary diverticula in our series. J. Magn. Reson. Imaging 2003;17:487–492. © 2003 Wiley‐Liss, Inc.
A manipulator system for 14‐gauge large core breast biopsies inside a high‐field whole‐body MR scanner
Authors: Pfleiderer Stefan O.R. , Reichenbach Jürgen R. , Azhari Tarek , Marx Christiane , Malich Ansgar , Schneider Achim , Vagner Jörg , Fischer Harald , Kaiser Werner A. 
Published: March 2003

AbstractPurposeTo investigate a robotic manipulator system for MR‐guided breast biopsies inside a 1.5 T whole‐body magnet.Materials and MethodsFourteen patients with suspicious breast lesions (diameter 18.6 ± 12 mm) underwent biopsy. Patients with malignant findings underwent surgery afterwards and the histologic findings between biopsy and surgery were correlated.ResultsIn five patients biopsy findings were histopathologically confirmed following open surgery. One tubular carcinoma was missed; one invasive cancer was underestimated. Seven patients with benign findings are still in the follow‐up period.ConclusionThe study demonstrates the feasibility to perform breast biopsies inside the magnet of a whole‐body MR scanner by using a manipulator system. J. Magn. Reson. Imaging 2003;17:493–498. © 2003 Wiley‐Liss, Inc.
Modelling evapotranspiration at three boreal forest stands using the CLASS: tests of parameterizations for canopy conductance and soil evaporation
Authors: Bartlett Paul A. , Harry McCaughey J. , Lafleur Peter M. , Verseghy Diana L. 
Published: March 2003

AbstractThe performance of the Canadian Land Surface Scheme (CLASS) was evaluated in off‐line runs, using data collected at three boreal forest stands located near Thompson, Manitoba: young jack pine, mature jack pine, and mature black spruce. The data were collected in the late spring through autumn of 1994 and 1996, as part of the Boreal Ecosystem–Atmosphere Study (BOREAS).The diurnal range in modelled soil heat flux was exaggerated at all sites. Soil evaporation was modelled poorly at the jack pine stands, with overestimation common and a step change to low evaporation as the soil dried. Replacing the soil evaporation algorithm, which was based on the estimation of a surface relative humidity value, with one based on soil moisture in the top soil layer reduced the overestimation and eliminated the step changes. Modelled water movement between soil layers was too slow at the jack pine stands. Modifying the soil hydraulic parameters to match an observed characteristic curve at the young jack pine stand produced a soil water suction that agreed more closely with measurements and improved drainage between soil layers.The latent heat flux was overestimated and the sensible heat flux underestimated at all three stands. New Jarvis–Stewart‐type canopy conductance algorithms were developed from stomatal conductance measurements. At the jack pine stands, stomatal conductance scaled by leaf area index reproduced canopy conductance, but a reduction in the scaled stomatal conductance by one half was necessary at the black spruce stand, indicating a nonlinearity in the scaling of stomatal conductance for this ecosystem. The root‐mean‐squared error for daily average latent heat flux for the control run of the CLASS and for the best test run are 49 W m−2 and 14 W m−2 respectively at the young jack pine stand, 50 W m−2 and 15 W m−2 respectively at the old jack pine stand, and 48 W m−2 and 13 W m−2 respectively at the old black spruce stand. Copyright © 2003 Royal Meteorological Society
Impact of the extratropical dynamical modes upon troposphere temperature using an approach based on advection of temperature
Authors: Gimeno Luis , Vidal Oscar , Nieto Raquel , de la Torre Laura , García Ricardo , Hernández Emiliano , Bojariu Roxana , Ribera Pedro , Gallego David 
Published: March 2003

AbstractAdvection of temperature (AT) is used to diagnose the influence of changes in extratropical atmospheric circulation on air temperature. AT is calculated at three different pressure levels (850, 500 and 200 hPa) for the period 1958–98 using NCEP–NCAR reanalysis data. Global and hemispheric annual series of AT have a common feature consisting of positive values and trends at 850 and 500 hPa and negative values and trends at 200 hPa, together with quasi‐biennial and quasi‐quadrennial oscillations for most of the series. Significant correlations were found between most of the Northern Hemisphere and global AT series with the Arctic oscillation and between most of the Southern Hemisphere and global AT series with the Antarctic oscillation. Copyright © 2003 Royal Meteorological Society