bluuebunny/crossref_metadata_2025_split huggingface dataset:
Perfusion imaging of the pancreas using an arterial spin labeling technique
Authors: Schraml Christina , Schwenzer Nina F. , Martirosian Petros , Claussen Claus D. , Schick Fritz 
Published: November 2008

AbstractPurposeTo investigate the feasibility of perfusion imaging of the pancreas using an arterial spin labeling (ASL) technique.Materials and MethodsAn adapted flow‐sensitive alternating inversion recovery (FAIR)‐TrueFISP ASL technique was implemented on a 1.5T scanner. Anatomical and perfusion imaging in three different parts of the pancreas were performed in 10 healthy volunteers. Quantitative perfusion values were calculated using the extended Bloch equations.ResultsPerfusion images of all subjects showed diagnostic image quality in the pancreatic tail and the head. Assessment of pancreatic tissue perfusion was possible in all organ parts. Mean perfusion values were 271 ± 79 mL/100g/min in the head, 351 ± 112 mL/100g/min in the body, and 243 ± 55 mL/100g/min in the tail of the pancreas. Total examination time for perfusion imaging of the entire organ was 15.4 minutes.ConclusionFAIR‐TrueFISP permits analysis of pancreatic tissue perfusion with good image quality in a clinically applicable measuring time. Assessment of perfusion disorders may be useful in the diagnosis of inflammatory pancreatic pathologies, endocrine and exocrine pancreatic disorders, and in monitoring of pancreatic transplants. J. Magn. Reson. Imaging 2008;28:1459–1465. © 2008 Wiley‐Liss, Inc.
Head‐to‐head comparison between delayed enhancement and percent infarct mapping for assessment of myocardial infarct size in a canine model
Authors: Ruzsics Balázs , Surányi Pál , Kiss Pál , Brott Brigitta C. , Elgavish Ada , Simor Tamas , Elgavish Gabriel A. 
Published: November 2008

AbstractPurposeTo compare a novel method, percent‐infarct‐mapping (PIM), with conventional delayed enhancement (DE) of contrast for accurate myocardial viability assessment. Contrary to signal intensity (SI), the longitudinal relaxation‐rate enhancement (ΔR1) is an intrinsic parameter linearly proportional to the concentration of contrast agent (CA). Determining ΔR1 voxel‐by‐voxel, after administering an infarct‐avid CA, allows determination of per‐voxel percentage of infarcted tissue. The feasibility of generating PIM is demonstrated in canine reperfused infarction using an infarct‐avid, persistent‐CA (PCA), (Gd)(ABE‐DTTA). PIM is compared to the DE method using Gd(DTPA), and both to triphenyltetrazolium chloride (TTC) staining histochemistry.Materials and MethodsIn six dogs, 48 hours following closed‐chest, 180‐minute coronary occlusion, DE imaging was carried out. PCA was administered immediately thereafter. Pixel‐by‐pixel R1 maps of the entire left ventricle (LV) were generated 48 hours after PCA using inversion‐recovery with multiple inversion times. R1, ΔR1, and percent‐infarct values were calculated voxel‐by‐voxel.ResultsSignificant correlations (P < 0.01, R ≥ 0.8) were obtained for percent‐infarct‐per‐slice (PIS) determined by DE or PIM vs. those from corresponding TTC‐stained slices. Compared to TTC, DE overestimated PIS by 32 ± 18%. PIM underestimated PIS by 2.5 ± 4.9%. Infarction fraction overestimation was 29 ± 6% of LV by DE, but only 1.0 ± 2.3% by PIM. Errors with PIM were significantly smaller than those with DE. Infarct area determined by signal intensity was similarly overestimated whether using Gd(DTPA) or Gd(ABE‐DTTA).ConclusionThe ΔR1‐based PIM method is highly reproducible and more accurate than DE for quantifying myocardial viability in vivo. J. Magn. Reson. Imaging 2008;28:1386–1392. © 2008 Wiley‐Liss, Inc.
Comparison of 2D and multislab 3D magnetic resonance techniques for measuring carotid wall volumes
Authors: Keenan Niall G. , Grasso Agata , Locca Didier , Roughton Michael , Gatehouse Peter D. , Firmin David N. , Pennell Dudley J. 
Published: November 2008

AbstractPurposeTo compare a multislab three‐dimensional volume‐selective fast spin‐echo (FSE) magnetic resonance (MR) sequence with a routine two‐dimensional FSE sequence for quantification of carotid wall volume.Materials and MethodsOne hundred normal subjects (50 men, mean age 44.6 years) underwent carotid vessel wall MR using 2D and 3D techniques. Carotid artery total vessel volume, lumen volume, wall volume, and wall/outer wall (W/OW) ratio were measured over 20 contiguous slices. Two‐ (2D) and three‐dimensional (3D) results were compared.ResultsThe mean difference between 2D and 3D datasets (as a percentage of the mean absolute value) was 1.7% for vessel volume, 4.9% for lumen volume, 4.7% for wall volume, and 5.8% for W/OW ratio. There was good correlation between 2D and 3D models for total vessel volume (R2 = 0.93, P < 0.001), lumen area (R2 = 0.92, P < 0.001), and wall volume (R2 = 0.77, P < 0.001). The correlation for the W/OW ratio was weaker (R2 = 0.30; P < 0.001). The signal‐to‐noise ratio (SNR) for the 3D technique was 2.1‐fold greater than for the 2D technique (P < 0.001). When using the 3D sequence, scan time was reduced by 63%.ConclusionMultislab volume selective 3D FSE carotid arterial wall imaging performs similarly to a conventional 2D technique, but with over twice the SNR and substantially reduced scan time. J. Magn. Reson. Imaging 2008;28:1476–1482. © 2008 Wiley‐Liss, Inc.
J‐difference lactate editing at 3.0 Tesla in the presence of strong lipids
Authors: Smith Mari A. , Koutcher Jason A. , Zakian Kristen L. 
Published: November 2008

AbstractPurposeTo implement in vivo detection of lactate in the presence of lipids by proton magnetic resonance spectroscopy at a 3 Tesla (T) field strength for potential applications in human tumors outside of the brain.Materials and MethodsThe BASING J‐difference sequence was implemented in the presence of high lipid concentrations in phantoms and in vivo at 3 Tesla.ResultsThe effectiveness of the lactate editing scheme is demonstrated in phantoms containing both lactate and lipids and in vivo in ischemic induced human muscle.ConclusionThe ability of the BASING J‐difference technique to detect lactate in the presence of strong lipid signals outside the brain at 3T is feasible. This robust technique should permit noninvasive lactate measurements in human tumors to investigate its potential as a prognostic indicator. J. Magn. Reson. Imaging 2008;28:1492–1498. © 2008 Wiley‐Liss, Inc.
Left ventricle segmentation using graph searching on intensity and gradient and a priori knowledge (lvGIGA) for short‐axis cardiac magnetic resonance imaging
Authors: Lee Hae‐Yeoun , Codella Noel , Cham Matthew , Prince Martin , Weinsaft Jonathan , Wang Yi 
Published: November 2008

AbstractPurposeTo develop and evaluate an automated left ventricle (LV) segmentation algorithm using Graph searching based on Intensity and Gradient information and A priori knowledge (lvGIGA).Materials and MethodsThe lvGIGA algorithm was implemented with coil sensitivity correction and polar coordinate transformation. Graph searching and expansion were applied for extracting myocardial endocardial and epicardial borders. LV blood and myocardium intensities were estimated for accurate partial volume calculation of blood volume and myocardial mass. Cardiac cine SSFP images were acquired from 38 patients. The lvGIGA algorithm was used to measure blood volume, myocardial mass, and ejection fraction, and compared with clinical manual tracing and the commercial MASS software.ResultsThe success rate for segmenting both endocardial and epicardial borders was 95.6% slices for lvGIGA and 37.8% for MASS (excluding basal slices that required manual enclosure of ventricle blood). The lvGIGA segmentation result agreed well with manual tracing, within −2.9 ± 4.4 mL, 2.1 ± 2.2%, and −9.6 ± 13.0 g, for blood volume, ejection fraction, and myocardial mass, respectively.ConclusionThe lvGIGA algorithm substantially improves the robustness of LV segmentation automation over the commercial MASS software, agrees well with clinical manual tracing, and may be a useful tool for clinical practice. J. Magn. Reson. Imaging 2008;28:1393–1401. © 2008 Wiley‐Liss, Inc.
Erythrocyte‐shape evolution recorded with fast‐measurement NMR diffusion–diffraction
Authors: Pages Guilhem , Szekely David , Kuchel Philip W. 
Published: November 2008

AbstractPurposeTo monitor red blood cell (RBC) shape evolution by 1H2O diffusion–diffraction NMR in time steps comparable to those required for the acquisition of a 31P NMR spectrum; thus, to correlate RBC mean diameter with ATP concentration after poisoning with NaF.Materials and MethodsPulsed‐field gradient‐stimulated echo (PFGSTE) diffusion experiments were recorded on 1H2O in RBC suspensions. Under conditions of restricted diffusion, q‐space experiments report on mean RBC diameter. To decrease experiment time, the phase cycling of radiofrequency (RF) pulses was cut to two transients by using unbalanced pairs of gradient pulses. Data processing used a recent digital filter. Differential interference contrast (DIC) light microscopy also recorded shape changes. 31P NMR spectroscopy gave estimates of mean ATP concentration.ResultsNaF caused RBC‐shape evolution from discocytes, through various forms of echinocytes, to spherocytes, over ∼6 h and ∼10 h at 37°C and 25°C, respectively. ATP declined to ∼0.5 its normal concentration before the first stage of discocyte transformation; the concentration was 0.0 after ∼1.5 h and 3.0 h, respectively, at the two temperatures.ConclusionRBC shape was readily monitored by NMR with a temporal resolution that was useful for correlations with both DIC microscopy and 31P NMR spectra. J. Magn. Reson. Imaging 2008;28:1409–1416. © 2008 Wiley‐Liss, Inc.
Effects of image normalization on the statistical analysis of perfusion MRI in elderly brains
Authors: Dai Weiying , Carmichael Owen T. , Lopez Oscar L. , Becker James T. , Kuller Lewis H. , Gach H. Michael 
Published: November 2008

AbstractPurposeTo fully understand the effects of an image processing methodology on the comparisons of regional patterns of brain perfusion over time and between subject groups.Materials and MethodsTwo brain normalization methods were compared using images of elderly controls and subjects with MCI and AD: the normalization package of statistical parametric mapping (SPM2), and a fully deformable model (FDM). The performance of these two normalization methods was quantitatively evaluated based on two criteria: (a) the alignment accuracy of five brain structures to the colin27 reference volume, and (b) impact of spatial normalization methods on the sensitivity of perfusion magnetic resonance imaging (pMRI).ResultsThe delineations of all five brain structures had significantly higher overlap with expert manual tracings using FDM compared to SPM (two‐tailed, P < 0.025). When applied to the biostatistical analysis of CBF maps, a larger number of statistically significant voxels was identified from FDM compared with SPM2 regardless of the effects of the threshold and smoothing kernel.ConclusionThe greater degree of deformation freedom associated with FDM may yield more accurate region matching and higher statistical sensitivity in identifying regions of CBF differences between elderly groups with prevalent late‐life neurodegenerative conditions. J. Magn. Reson. Imaging 2008;28:1351–1360. © 2008 Wiley‐Liss, Inc.
Revisiting anaplastic astrocytomas I: An expansive growth pattern is associated with a better prognosis
Authors: Moulding Hugh D. , Friedman David P. , Curtis Mark , Kenyon Lawrence , Flanders Adam E. , Paek Sun Ha , Andrews David W. 
Published: November 2008

AbstractPurposeTo study whether anaplastic astrocytomas that are nonenhancing and/or well‐circumscribed (expansive) are associated with a better prognosis.Materials and MethodsWe retrospectively identified 59 patients with pathologically confirmed World Health Organizaiton (WHO) grade III anaplastic astrocytoma who underwent craniotomy at our institution from 1995 through 2006. We assessed prognostic variables including age, enhancement (EAA—34 patients) vs. nonenhancement (NEAA—25 patients), MR growth patterns (expansive [28 patients] vs. mixed/infiltrative [31 patients]), recursive partitioning analysis (RPA) class, resection extent, and addition of chemotherapy. Primary outcome measure was survival.ResultsKaplan‐Meier curves showed improved survival in NEAA, expansive tumors, and RPA 1 class patients. Within RPA class I patients, expansive growth pattern remained a significant advantage in survival time. Examining extent of resection also showed that patients with gross total resections (GTR) had a better prognosis. A multivariate (Cox proportional hazards) analysis showed that patient age and expansive tumor phenotype affected outcome, whereas RPA class, enhancement, and GTR did not.ConclusionCircumscribed growth in histologically proven anaplastic astrocytoma, which has not been emphasized in past studies, has a considerable survival advantage. J. Magn. Reson. Imaging 2008;28:1311–1321. © 2008 Wiley‐Liss, Inc.
Revisiting anaplastic astrocytomas II: Further characterization of an expansive growth pattern with visually enhanced diffusion tensor imaging
Authors: Guan Xin , Lai Song , Lackey John , Shi Jianrong , Techavipoo Udomchai , Moulding Hugh D. , Flanders Adam E. , Andrews David W. 
Published: November 2008

AbstractPurposeTo seek to distinguish and visualize the different magnetic resonance imaging (MRI) growth patterns among malignant gliomas utilizing visually enhanced diffusion tensor imaging (DTI).Materials and MethodsNineteen consecutive patients undergoing image‐guided resection of a newly diagnosed malignant glioma underwent add‐on acquisition of DTI data based on an Institutional Review Board (IRB)‐approved imaging protocol during preoperative MRI scans for routine intraoperative image guidance. Tumor growth patterns were assigned to expansive or mixed/infiltrative classes as described in the companion article (24). Infiltrating tumors were WHO Grade IV astrocytomas and all expansive tumors were either WHO Grade III astrocytomas or WHO Grade II astrocytomas. DTI‐based white matter tractography was conducted and the DTI data were fused with anatomical images using an in‐house software package we developed to enhance the visualization of the tumor/fiber interface. In one case additional analysis was performed with 2D multivoxel1H‐MRSI utilizing a 2D chemical shift imaging (CSI) technique to corroborate the nature of this interface.ResultsOut of the 19 tumor patients studied, 11 had infiltrative tumors and the other 8 had expansive tumors. While less clear with 2D axial diffusion color maps, visually enhanced 3D reconstructions of the tumor/fiber interface successfully corroborated distinctive growth patterns. This was particularly evident when viewed in 3D video loops of each tumor/fiber interface.ConclusionWe have successfully developed software that visually enhances the anatomic details of the tumor/fiber interface in patients with anaplastic astrocytomas. These data support the existence of a subgroup of patients within the WHO Grade III classification with expansive tumors and a significantly better prognosis. J. Magn. Reson. Imaging 2008;28:1322–1336. © 2008 Wiley‐Liss, Inc.
Free‐breathing high‐spatial‐resolution delayed contrast‐enhanced three‐dimensional viability MR imaging of the myocardium at 3.0T: A feasibility study
Authors: Amano Yasuo , Matsumura Yoshio , Kumita Shinichiro 
Published: November 2008

AbstractPurposeTo assess the feasibility of free‐breathing high‐spatial‐resolution delayed contrast‐enhanced three‐dimensional (3D) viability magnetic resonance imaging (MRI) at 3.0T for the detection of myocardial damages.Materials and MethodsTwenty‐five patients with myocardial diseases, including myocardial infarction and cardiomyopathies, were enrolled after informed consent was given. Free‐breathing 3D viability MRI with high spatial resolution (1.5 × 1.25 × 2.5 mm) at 3.0T, for which cardiac and navigator gating techniques were employed, was compared with breath‐hold two‐dimensional (2D) viability imaging (1.77 × 1.18 × 10 mm) for assessment of contrast‐to‐noise ratio (CNR) and myocardial damage.ResultsFree‐breathing 3D viability imaging was achieved successfully in 21 of the 25 patients. This imaging technique depicted 84.6% of hyperenhancing myocardium with a higher CNR between hyperenhancing myocardium and blood and with excellent agreement for the transmural extension of myocardial damage (k = 0.91). In particular, the 3D viability images delineated the myocardial infarction and linear hyperenhancing myocardium, comparable to the 2D viability images.ConclusionFree‐breathing high‐spatial‐resolution delayed contrast‐enhanced 3D viability MRI using 3.0T was feasible for the evaluation of hyperenhancing myocardium, as seen with myocardial infarction and cardiomyopathies. J. Magn. Reson. Imaging 2008;28:1361–1367. © 2008 Wiley‐Liss, Inc.
Longitudinal in vivo susceptibility contrast MRI measurements of LS174T colorectal liver metastasis in nude mice
Authors: Kalber Tammy L. , Waterton John C. , Griffiths John R. , Ryan Anderson J. , Robinson Simon P. 
Published: November 2008

AbstractPurposeTo characterize longitudinal tumor progression in a murine orthotopic model of liver metastasis using susceptibility contrast magnetic resonance imaging (MRI).Materials and MethodsNude mice were inoculated intrasplenically with LS174T colorectal carcinoma cells 24 hours postadministration of 2.5 mgFe/kg of the ultrasmall superparamagnetic iron oxide particle preparation feruglose. Contiguous T2 and T2*‐weighted multislice MR images were acquired 10, 15, 20, 25, 30, and 35 days postinoculation to longitudinally evaluate metastatic progression. Functional tumor vasculature and hypoxia were histologically evaluated at the final timepoint using Hoechst 33342 uptake, pimonidazole and hematoxylin and eosin staining. A parallel cohort of subcutaneous tumors was included for comparison.ResultsAll intrasplenically inoculated mice developed liver metastases, evident in both T2*‐ and T2‐weighted images as high‐signal deposits, compared to feruglose‐nulled normal liver. Small lesions were detected as early as day 10 and all mice exhibited progressing lesions over 35 days. Liver metastases took longer to establish, but exhibited a similar volume doubling time to the subcutaneously propagated tumors of ≈2–3 days. Different functional tumor vascular architectures between the two growth sites were apparent.ConclusionSusceptibility‐contrast MRI using a single dose of feruglose can be used to easily detect and longitudinally monitor orthotopically propagated liver metastases in vivo. J. Magn. Reson. Imaging 2008;9999:1451–1458. © 2008 Wiley‐Liss, Inc.
Quantification of absolute fat mass using an adipose tissue reference signal model
Authors: Hu Houchun H. , Nayak Krishna S. 
Published: November 2008

AbstractPurposeTo develop a method for quantifying absolute fat mass, and to demonstrate its feasibility in phantoms and in ex vivo swine specimens at 3 Tesla.Materials and MethodsChemical‐shift‐based fat‐water decomposition was used to first reconstruct fat‐only images. Our proposed model used a reference signal from fat in pure adipose tissue to calibrate and normalize the fat signal intensities from the fat‐only images. Fat mass was subsequently computed on a voxel‐by‐voxel basis and summed across each sample. Feasibility of the model was tested in six ex vivo swine samples containing varying mixtures of fat (adipose) and lean tissues. The samples were imaged using 1.5‐mm isotropic voxels and a single‐channel birdcage head coil at 3 Tesla. Lipid assay was independently performed to determine fat mass, and served as the comparison standard.ResultsAbsolute fat mass values (in grams) derived by our proposed model were in excellent agreement with lipid assay results, with a 5% to 7% difference (r > 0.99; P < 0.001).ConclusionPreliminary results in ex vivo swine samples demonstrated the feasibility of computing absolute fat mass as a quantitative endpoint using chemical‐shift fat‐water MRI with a signal model based on reference fat from pure adipose tissue. J. Magn. Reson. Imaging 2008;28:1483–1491. © 2008 Wiley‐Liss, Inc.
Age‐related non‐Gaussian diffusion patterns in the prefrontal brain
Authors: Falangola Maria F. , Jensen Jens H. , Babb James S. , Hu Caixia , Castellanos Francisco X. , Di Martino Adriana , Ferris Steven H. , Helpern Joseph A. 
Published: November 2008

AbstractPurposeTo characterize age‐related MR diffusion patterns of the prefrontal brain cortex microstructure using a new method for investigating the non‐Gaussian behavior of water diffusion called diffusional kurtosis imaging (DKI).Materials and MethodsMeasures of mean diffusivity (MD), fractional anisotropy (FA) and mean kurtosis (MK) were compared in the prefrontal brain cortex of 24 healthy volunteers (adolescents, young adults, and elderly) ranging from age 13 to 85 years. A Mann‐Whitney test was used to compare subject groups with respect to the diffusion measures, and linear regression was used to characterize the change in each diffusion measure as a function of age.ResultsWe found significant age‐related changes in the elderly adult group, with increase of MD and decrease of FA.ConclusionThe current study demonstrates distinct mean kurtosis patterns for different age‐ranges, with significant age‐related correlation for mean kurtosis (MK) and MK peak position, showing that diffusional kurtosis is able to characterize and measure age‐related diffusion changes for both grey and white matter, in the developing and aging brain. J. Magn. Reson. Imaging 2008;28:1345–1350. © 2008 Wiley‐Liss, Inc.
Two different types of ring‐like enhancement on dynamic MR imaging in breast cancer: Correlation with the histopathologic findings
Authors: Kobayashi Miki , Kawashima Hiroko , Matsui Osamu , Zen Yoh , Suzuki Masayuki , Inokuchi Masafumi , Noguchi Masakuni , Ohta Tetsuo 
Published: November 2008

AbstractPurposeTo describe two different types of “ring‐like enhancement” seen on dynamic magnetic resonance imaging (MRI) of breast cancer, and compare their histopathological features.Materials and MethodsA total of 326 breast carcinomas in 311 patients were evaluated regarding the existence and appearance of “ring‐like enhancement” in comparison to other MR imaging and histopathological findings.ResultsEarly peripheral enhancement (EPE) was observed in 81 of 326 lesions (24.8%) and delayed rim enhancement (DRE) in 110 (33.7%). Spiculated mass, invasive ductal carcinoma with abundant stroma, central fibrosis/necrosis, and a higher degree of fat invasion correlated with EPE (P < 0.001). DRE correlated with lobulated or round mass with a smooth border, invasive ductal carcinoma with scanty stroma, higher degrees of inflammatory change and surrounding compressed tissue, and less fat invasion (P <0.001). EPE correlated with the ratio of the peripheral to central blood vessel density (P = 0.0036) and DRE with the ratio of the peritumoral to peripheral lymph vessel density (P = 0.0298).ConclusionThe appearance of two different types of ring‐like enhancement on dynamic MRI in breast cancers was affected by the morphologic features, various histological factors reflecting the growth pattern of the mass, and angiogenesis and lymphangiogenesis. J. Magn. Reson. Imaging 2008;28:1435–1443. © 2008 Wiley‐Liss, Inc.