bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of referenceless thermometry in MRI‐guided focused ultrasound surgery of uterine fibroids
Authors: McDannold Nathan , Tempany Clare , Jolesz Ferenc , Hynynen Kullervo 
Published: September 2008

AbstractPurposeTo clinically assess a previously described method (Rieke et.al., Magn Reson Med 2004) to produce more motion‐robust MRI‐based temperature images using data acquired during MRI‐guided focused ultrasound surgery (MRgFUS) of uterine fibroids.Materials and MethodsThe method (“referenceless thermometry”) uses surface fitting in nonheated regions of individual phase images to extrapolate and then remove background phase variations that are unrelated to temperature changes. We tested this method using images from 100 sonications selected from 33 patient MRgFUS treatments. Temperature measurements and thermal dose contours estimated with the referenceless method were compared with those produced with the standard phase‐difference technique. Fitting accuracy and noise level were also measured.ResultsIn 92/100 sonications, the difference between the two measurements was less than 3°C. The average difference in the measurements was 1.5 ± 1.4°C. Small motion artifacts were observed in the phase‐difference imaging when the difference was greater than 3°C. The method failed in two cases. The mean absolute error in the surface fit in baseline images corresponded to a temperature error of 0.8 ± 1.4°C. The noise level was approximately 40% lower than the phase‐difference method. Thermal dose contours calculated from the two methods agreed well on average.ConclusionBased on the small error when compared with the standard technique, this method appears to be adequate for temperature monitoring of MRgFUS in uterine fibroids and may prove useful for monitoring temperature changes in moving organs. J. Magn. Reson. Imaging 2008;28:1026–1032. © 2008 Wiley‐Liss, Inc.
Identifying lesion growth with MR imaging in acute ischemic stroke
Authors: Bristow Michael S. , Poulin Brett W. , Simon Jessica E. , Hill Michael D. , Kosior Jayme C. , Coutts Shelagh B. , Frayne Richard , Mitchell J. Ross , Demchuk Andrew M. 
Published: September 2008

AbstractPurposeTo determine whether different MR diffusion‐ and perfusion‐weighted imaging (DWI and PWI) parameters are important in distinguishing lesion growth from the acute lesion and from oligemia.Materials and MethodsMR DWI and PWI were acquired from thirteen patients. We defined three regions: (i) LESION ‐ intersection of acute and final lesions, (ii) GROWTH ‐ portion of final lesion not part of acute lesion, and (iii) OLIGEMIA ‐ region of perfusion abnormality not part of either the acute or final lesions. We used logistic regression modeling to distinguish GROWTH from LESION and from OLIGEMIA on a voxel‐wise basis using DWI‐ and PWI‐based parameters. Final models were selected based on the Wald statistic and validated by cross‐validation using the mean (± standard deviation) area under the curve (AUC) from receiver operating characteristic analysis.ResultsThe final model for differentiating GROWTH from LESION included DWI, the apparent diffusion coefficient (ADC), cerebral blood flow (CBF) and tissue type (AUC = 0.939 ± 0.028). The final model for differentiating GROWTH from OLIGEMIA included DWI, ADC, CBF, and time‐to‐peak (AUC = 0.793 ± 0.106).ConclusionDifferent MR parameters are important in differentiating lesion growth from acute lesion and from oligemia in acute ischemic stroke. J. Magn. Reson. Imaging 2008;28:837–846. © 2008 Wiley‐Liss, Inc.
Quantitative analysis of diffusion‐weighted magnetic resonance imaging of the pancreas: Usefulness in characterizing solid pancreatic masses
Authors: Lee Seung Soo , Byun Jae Ho , Park Beom Jin , Park Seong Ho , Kim Namkug , Park Bumwoo , Kim Jeong Kon , Lee Moon‐Gyu 
Published: September 2008

AbstractPurposeTo evaluate whether measurement of apparent diffusion coefficient (ADC) and pure diffusion coefficient (D) can help to characterize solid pancreatic masses.Materials and MethodsDiffusion‐weighted MR imaging was performed in both a patient group (n = 71; pancreatic cancer [n = 47], mass‐forming pancreatitis [n = 13], solid pseudopapillary neoplasm [n = 6], and neuroendocrine tumor [n = 5]) and a normal control group (n = 11) by applying three b‐factors of 0, 500, and 1000 sec/mm2. ADC500, ADC1000, D (ADC using b = 500 and 1000 sec/mm2), and perfusion fraction (f, 1‐ exp [‐500 sec/mm2 × (ADC500 – D)]) of normal pancreas, pancreatic cancer, and mass‐forming pancreatitis were compared using the Kruskal–Wallis test. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance and optimal cutoff value of these parameters in differentiating pancreatic cancer from mass‐forming pancreatitis.ResultsNormal pancreas had significantly higher mean ADC500, ADC1000, and f than either pancreatic cancer (P < 0.001, < 0.001, and 0.004, respectively) or mass‐forming pancreatitis (P < 0.001, < 0.001, and 0.002, respectively). ADC500, ADC1000, and D of mass‐forming pancreatitis were significantly lower than those of pancreatic cancer (P = 0.002, 0.004, and 0.014, respectively). Sensitivities and specificities in the diagnosis of pancreatic cancer were 72.3% and 76.9% for ADC500, 87.2% and 69.2% for ADC1000, 87.2% and 61.5% for D, and 42.6% and 92.3% for f, respectively.ConclusionMeasurement of ADC and D may be helpful in differentiating pancreatic cancers from mass‐forming pancreatitis. J. Magn. Reson. Imaging 2008;28:928–936. © 2008 Wiley‐Liss, Inc.
USPIO (Ferumoxtran‐10)‐enhanced MRI to visualize reticuloendothelial system cells in neonatal rats: Feasibility and biodistribution study
Authors: Azoulay Robin , Olivier Paul , Baud Olivier , Verney Catherine , Santus Robin , Robert Philippe , Gressens Pierre , Sebag Guy 
Published: September 2008

AbstractPurposeTo investigate whether USPIO‐enhanced magnetic resonance imaging (MRI) detected reticuloendothelial system (RES) cells in newborn normal rats.Materials and MethodsNewborn normal rats were imaged in vivo on a 1.5 T MR system, 2–96 hours after intraperitoneal Ferumoxtran‐10 (n = 38) or saline injection (control group, n = 5). Signals from liver, spleen, and vertebral bone marrow were measured (T2‐weighted Turbo Spin Echo) to describe the kinetics of enhancement. The pups were sacrificed and iron concentrations in plasma and peritoneal fluid were measured using atomic absorption spectrometry. Prussian blue‐labeled cells density in liver, spleen, and vertebral bone marrow was assessed.ResultsSignificant (P < 0.05) negative enhancement of the liver, spleen, and vertebral bone marrow was noted after Ferumoxtran‐10 injection (2–96 hours for liver and spleen, 4–96 hours for bone marrow). Ferumoxtran‐10 was absorbed from the peritoneum in the first 8 hours postinjection, entering the circulation with a plasma peak (8 hours); then Ferumoxtran‐10 returned over the baseline in plasma (96 hours). Important intracellular iron deposition in liver and spleen was measured postinjection (3–96 hours, P < 0.05). Limited but significant intracellular iron deposition was noted in vertebral bone marrow postinjection (96 hours, P < 0.05), suggesting that Ferumoxtran‐10 selectively labeled RES cells after 96 hours and produced nonspecific labeling at earlier timepoints.ConclusionFerumoxtran‐10‐enhanced MRI visualizes RES cells in vivo in newborn rats. J. Magn. Reson. Imaging 2008;28:1046–1052. © 2008 Wiley‐Liss, Inc.
Improvement of MRI‐functional measurement with automatic movement correction in native and transplanted kidneys
Authors: de Senneville Baudouin Denis , Mendichovszky Iosif Alexandru , Roujol Sébastien , Gordon Isky , Moonen Chrit , Grenier Nicolas 
Published: September 2008

AbstractPurposeTo improve 2D software for motion correction of renal dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) and to evaluate its effect using the Patlak–Rutland model.Materials and MethodsA subpixel‐accurate method to correct for kidney motion during DCE‐MRI was evaluated on native and transplanted kidneys using data from two different institutions with different magnets and protocols. The Patlak–Rutland model was used to calculate glomerular filtration rate (GFR) on a voxel‐by‐voxel basis providing mean (K̄p) and uncertainty (σ(Kp)) values for GFR.ResultsIn transplanted kidneys, average absolute variation of K̄p was 6.4% ± 4.8% (max = 16.6%). In native kidneys average absolute variation of K̄p was 12.11% ± 6.88% (max = 25.6%) for the right and 11.6% ± 6% (max = 20.8%) for the left. Movement correction showed an average reduction ofσ(Kp) of 6.9% ± 6.6% (max = 21.4%) in transplanted kidneys, 30.9% ± 17.6% (max = 60.8%) for the right native kidney, and 31.8% ± 14% (max = 55.3%) for the left kidney.ConclusionThe movement correction algorithm showed improved uncertainty on GFR computation for both native and transplanted kidneys despite different spatial resolution from the different MRI systems and different levels of signal‐to‐noise ratios on DCE‐MRI. J. Magn. Reson. Imaging 2008;28:970–978. © 2008 Wiley‐Liss, Inc.
Magnetization transfer contrast and T2 mapping in the evaluation of cartilage repair tissue with 3T MRI
Authors: Welsch Goetz H. , Trattnig Siegfried , Scheffler Klaus , Szomonanyi Pavol , Quirbach Sebastian , Marlovits Stefan , Domayer Stephan , Bieri Oliver , Mamisch Tallal C. 
Published: September 2008

AbstractPurposeTo use magnetization transfer (MT) imaging in the visualization of healthy articular cartilage and cartilage repair tissue after different cartilage repair procedures, and to assess global as well as zonal values and compare the results to T2‐relaxation.Materials and MethodsThirty‐four patients (17 after microfracture [MFX] and 17 after matrix‐associated autologous cartilage transplantation [MACT]) were examined with 3T MRI. The MT ratio (MTR) was calculated from measurements with and without MT contrast. T2‐values were evaluated using a multiecho, spin‐echo approach. Global (full thickness of cartilage) and zonal (deep and superficial aspect) region‐of‐interest assessment of cartilage repair tissue and normal‐appearing cartilage was performed.ResultsIn patients after MFX and MACT, the global MTR of cartilage repair tissue was significantly lower compared to healthy cartilage. In contrast, using T2, cartilage repair tissue showed significantly lower T2 values only after MFX, whereas after MACT, global T2 values were comparable to healthy cartilage. For zonal evaluation, MTR and T2 showed a significant stratification within healthy cartilage, and T2 additionally within cartilage repair tissue after MACT.ConclusionMT imaging is capable and sensitive in the detection of differences between healthy cartilage and areas of cartilage repair and might be an additional tool in biochemical cartilage imaging. For both MTR and T2 mapping, zonal assessment is desirable. J. Magn. Reson. Imaging 2008;28:979–986. © 2008 Wiley‐Liss, Inc.
Reactive hyperemia and BOLD MRI demonstrate that VEGF inhibition, age, and atherosclerosis adversely affect functional recovery in a murine model of peripheral artery disease
Authors: Greve Joan M. , Williams Simon P. , Bernstein Lisa J. , Goldman Hope , Peale Franklin V. , Bunting Stuart , van Bruggen Nicholas 
Published: September 2008

AbstractPurposeTo develop magnetic resonace imaging (MRI) methods for functional assessment of arteriogenesis in a murine model of peripheral artery disease to quantify the influences of vascular endothelial growth factor (VEGF), age, and atherosclerosis.Materials and MethodsReactive hyperemia (RH), which was induced using a device designed for remote and transient occlusion of the aorta and vena cava, was measured by blood‐oxygen‐level–dependent MRI. Twenty‐eight days after femoral artery ligation, peak height (PH) and time to peak (TTP) of the RH response was compared with sham‐operated animals in 10‐week‐old C57Bl6, 9‐month‐old C57Bl6, and 9‐month‐old Ldlr−/−Apobec−/− mice. The contribution of VEGF to functional recovery was assessed in young mice. Angiogenesis was quantified using an anti‐PECAM1 radioimmunoassay.ResultsIn young animals, angiogenesis was maximal 7 days after ligation, whereas functional recovery took 28 days. Inhibition of VEGF eliminated the angiogenesis seen at 7 days and reduced RH (PH, P < 0.05). At day 28, RH was altered in old (TTP, P < 0.05) and atherosclerotic (PH, P < 0.05; TTP, P < 0.05) animals. RH was different in young, old, and atherosclerotic sham animals. Old and atherosclerotic mice showed reduced angiogenesis.ConclusionThe method presented herein can provide a sensitive assay for the functional assessment of arteriogenesis and highlights the contribution of VEGF, age, and atherosclerosis to this process. J. Magn. Reson. Imaging 2008;28:996–1004. © 2008 Wiley‐Liss, Inc.
Transvascular and interstitial transport in rat hepatocellular carcinomas: Dynamic contrast‐enhanced MRI assessment with low‐ and high‐molecular weight agents
Authors: Michoux Nicolas , Huwart Laurent , Abarca‐Quinones Jorge , Dorvillius Mylène , Annet Laurence , Peeters Frank , Van Beers Bernard E. 
Published: September 2008

AbstractPurposeTo assess which MRI‐derived kinetic parameters reflect decreased transvascular and interstitial transport when low‐ and high‐molecular‐weight agents are used in rat hepatocellular carcinomas.Materials and MethodsDynamic MRI after injection of a low‐molecular‐weight contrast agent of 0.56 kDa (Gd‐DOTA, gadoterate) and two high‐molecular‐weight contrast agents of 6.47 kDa (P792, gadomelitol) and 52 kDa (P717, carboxymethyldextran Gd‐DOTA) was performed in rats with chemically induced hepatocellular carcinomas. The data were analyzed with the Kety compartmental model, the extended Kety compartmental model in which it is assumed that the tissue voxels contain a vascular component, and the St Lawrence and Lee distributed‐parameter model.ResultsThe extravascular extracellular space accessible to the contrast agent ve and the extraction fraction E decreased with increasing molecular weight of the contrast agent. In contrast, the volume transfer constant Ktrans did not differ significantly when low‐ or high‐molecular‐weight agents were used.ConclusionIn this animal model the results suggest that the accessible extravascular extracellular space and the extraction fraction are more sensitive indicators of decreased transvascular and interstitial transport with high‐molecular‐weight agents than the volume transfer constant, which is a lumped representation of blood flow and permeability. J. Magn. Reson. Imaging 2008;28:906–914. © 2008 Wiley‐Liss, Inc.
Perfusion‐weighted magnetic resonance imaging patterns of hypoxic–ischemic encephalopathy in term neonates
Authors: Wintermark Pia , Moessinger Adrien C. , Gudinchet François , Meuli Reto 
Published: September 2008

AbstractPurposeTo determine whether an early magnetic resonance imaging (MRI) study using perfusion‐weighted imaging (PWI) may define the pattern of brain injury in term neonatal hypoxic–ischemic (HI) encephalopathy.Materials and MethodsFive newborns with HI encephalopathy or a marker of perinatal depression, and 2 controls underwent an early MRI (at 2 to 4 days), including PWI. Relative cerebral blood flow (rCBF) values were measured.ResultsOn early (≤4 days) PWI‐MRI, marked hyperperfusion was seen in areas of HI brain damage, allowing the classification of the children into different patterns according to the predominant site of injury: 1 with a “normal pattern”; 1 with a “watershed pattern” with increased rCBF ratios in white matter; 1 with a “basal ganglia pattern” with increased rCBF ratios in basal ganglia; and 2 with a “total cortical pattern” with increased rCBF ratios in cortical gray matter, white matter, and basal ganglia. These patterns were confirmed in all infants on late (9 to 11 days) conventional MRI (T2‐weighted images) (4 of 5 patients) or on postmortem examination (1 of 5 patients).ConclusionPWI is technically feasible in neonates with HI encephalopathy in a reproducible way, permitting comparisons between children. It provides a practical means to identify early after birth the future definitive ischemic areas that may be shown on conventional MRI only later. J. Magn. Reson. Imaging 2008;28:1019–1025. © 2008 Wiley‐Liss, Inc.
In vivo 1H magnetic resonance spectroscopy of amniotic fluid and fetal lung at 1.5 T: Technical challenges
Authors: Kim Dong‐Hyun , Vahidi Kiarash , Caughey Aaron B. , Coakley Fergus V. , Vigneron Daniel B. , Kurhanewicz John , Mow Ben , Joe Bonnie N. 
Published: September 2008

AbstractPurposeTo identify the major technical challenges associated with in utero single‐voxel proton spectroscopy of amniotic fluid and fetal lung and to evaluate the feasibility of performing in utero fetal spectroscopy for fetal lung maturity testing.Materials and MethodsFetal magnetic resonance (MR) spectroscopy of amniotic fluid and fetal lung were performed at 1.5 T in 8 near‐term pregnant women. Presence/absence of lactate and choline peaks was tabulated. Ex vivo spectra were obtained from amniotic fluid samples to investigate and refine sequence parameters.ResultsSpectroscopy failed in 3 of 8 cases due to maternal discomfort (n = 1) or fetal gastroschisis (n = 2). Both fetal motion and low signal‐to‐noise ratio were limiting factors for the remaining 5 clinical in vivo studies at 1.5 T. Ex vivo and in vivo studies suggested feasibility for detecting lactate from amniotic fluid within a reasonable clinical scan time (4–5 minutes). Lactate was detected in 3 of 5 patients. Choline detection was limited and was detected in 1 patient.ConclusionMinor motion effects can be overcome but continuous fetal motion is problematic. Lactate detection seems clinically feasible, but choline detection requires additional technical development and, potentially, further imaging at a higher field strength because of the low signal‐to‐noise ratio at 1.5 T. J. Magn. Reson. Imaging 2008;28:1033–1038. © 2008 Wiley‐Liss, Inc.
Signal features of the atherosclerotic plaque at 3.0 Tesla versus 1.5 Tesla: Impact on automatic classification
Authors: Kerwin William S. , Liu Fei , Yarnykh Vasily , Underhill Hunter , Oikawa Minako , Yu Wei , Hatsukami Thomas S. , Yuan Chun 
Published: September 2008

AbstractPurposeTo investigate the impact of different field strengths on determining plaque composition with an automatic classifier.Materials and MethodsWe applied a previously developed automatic classifier—the morphology enhanced probabilistic plaque segmentation (MEPPS) algorithm—to images from 20 subjects scanned at both 1.5 Tesla (T) and 3T. Average areas per slice of lipid‐rich core, intraplaque hemorrhage, calcification, and fibrous tissue were recorded for each subject and field strength.ResultsAll measurements showed close agreement at the two field strengths, with correlation coefficients of 0.91, 0.93, 0.95, and 0.93, respectively. None of these measurements showed a statistically significant difference between field strengths in the average area per slice by a paired t‐test, although calcification tended to be measured larger at 3T (P = 0.09).ConclusionAutomated classification results using an identical algorithm at 1.5T and 3T produced highly similar results, suggesting that with this acquisition protocol, 3T signal characteristics of the atherosclerotic plaque are sufficiently similar to 1.5T characteristics for MEPPS to provide equivalent performance. J. Magn. Reson. Imaging 2008;28:987–995. © 2008 Wiley‐Liss, Inc.
Diffusion‐weighted MR imaging for the evaluation of seminal vesicle invasion in prostate cancer: Initial results
Authors: Kim Chan Kyo , Choi Dongil , Park Byung Kwan , Kwon Ghee Young , Lim Hyo Keun 
Published: September 2008

AbstractPurposeTo evaluate the accuracy of T2‐weighted (T2WI) with diffusion‐weighted imaging (DWI) as compared with T2WI alone for predicting seminal vesicle invasion (SVI) of prostate cancer.Materials and MethodsA total of 30 patients with SVI and 136 patients without SVI who underwent prostate MR imaging were included in the study. MR images were analyzed retrospectively and independently by two readers for SVI on T2WI and T2WI with DWI using a 5‐point scale.ResultsFor predicting SVI, the specificity for T2WI with DWI and for T2WI was 97% and 87%, respectively, and accuracy was 96% and 87%, respectively, as determined by the experienced reader (P < 0.01). For the less experienced reader, the specificity for T2WI with DWI and for T2WI was 96% and 81%, respectively, and accuracy was 90% and 77%, respectively (P < 0.01). The diagnostic performance of the less experienced reader with T2WI with DWI led to significant improvement of the area under the receiver operating characteristic curve (Az) as compared with T2WI alone (Az = 0.815 versus 0.696; P < 0.01). Interreader agreement showed a substantial agreement (κ = 0.613) for T2WI, and a substantial agreement (κ = 0.737) for T2WI with DWI.ConclusionFor predicting SVI, T2WI with DWI showed a better diagnostic performance than T2WI alone. Additionally, the accuracy of the less experienced reader using T2WI with DWI showed a significant improvement as compared with T2WI alone. J. Magn. Reson. Imaging 2008;28:963–969. © 2008 Wiley‐Liss, Inc.
In vivo estimation and repeatability of force–length relationship and stiffness of the human achilles tendon using phase contrast MRI
Authors: Shin Dongsuk , Finni Taija , Ahn Sinyeob , Hodgson John A. , Lee Hae‐Dong , Edgerton V. Reggie , Sinha Shantanu 
Published: September 2008

AbstractPurposeTo devise a method using velocity encoded phase contrast MRI and MR‐compatible dynamometry, for in vivo estimation of elastic properties of the human Achilles tendon and to assess within‐session and day‐to‐day repeatability of this technique.Materials and MethodsAchilles tendon force and calcaneus‐movement‐adjusted displacement were measured during a submaximal isometric plantarflexion in 4 healthy subjects, four repeated trials each. The measured force‐length (F‐L) relationship was least‐squares fitted to a cubic polynomial. Typical error was calculated for tendon displacement at multiple force levels, stiffness from the “linear region,” and transition point from the displacement point separating the linear and nonlinear parts of the curve.ResultsDisplacements of the tendon were determined up to a maximum force of 500N, with mean stiffness of 234 ± 53 N/mm, mean transition point of 2.70 ± 0.23 mm and maximum tendon displacement of 3.38 mm. Variability of tendon displacement was not dependent on the force level. Overall typical errors were 0.09 mm and 0.16 mm for within‐session and between days, respectively. Typical error of transition point was 0.05 mm and 0.14 mm. Stiffness had typical errors of 47.24 N/mm and 51.95 N/mm. The tendon cross‐sectional area and calcaneus displacement were found to be very significant factors in minimizing the individual differences in F‐L curves.ConclusionThe method yielded F‐L relationships, stiffness, and transition point values that showed good within and day‐to‐day repeatability. The technique compared well with the more conventional one using ultrasonography. Its reliability indicates potential for measuring tendon structural changes after an injury, disease, and altered loading. J. Magn. Reson. Imaging 2008;28:1039–1045. © 2008 Wiley‐Liss, Inc.