bluuebunny/crossref_metadata_2025 huggingface dataset:
Thymoquinone induces apoptosis through activation of caspase‐8 and mitochondrial events in p53‐null myeloblastic leukemia HL‐60 cells
Authors: El‐Mahdy Mohamed A. , Zhu Qianzheng , Wang Qi‐En , Wani Gulzar , Wani Altaf A.
Published: May 2005

Thymoquinone (TQ), the major biologically active component isolated from a traditional medicinal herb, Nigella sativa Linn, is a potential chemopreventive and chemotherapeutic compound. Despite the promising antineoplastic activities of TQ, the molecular mechanism of its pharmacologic effects is poorly understood. Here, we report that TQ exhibits antiproliferative effect, induces apoptosis, disrupts mitochondrial membrane potential and triggers the activation of caspases 8, 9 and 3 in myeloblastic leukemia HL‐60 cells. The apoptosis induced by TQ was inhibited by a general caspase inhibitor, z‐VAD‐FMK; a caspase‐3‐specific inhibitor, z‐DEVD‐FMK; as well as a caspase‐8‐specific inhibitor, z‐IETD‐FMK. Moreover, the caspase‐8 inhibitor blocked the TQ‐induced activation of caspase‐3, PARP cleavage and the release of cytochrome c from mitochondria into the cytoplasm. In addition, TQ treatment of HL‐60 cells caused a marked increase in Bax/Bcl2 ratios due to upregulation of Bax and downregulation of Bcl2 proteins. These results indicate that TQ‐induced apoptosis is associated with the activation of caspases 8, 9 and 3, with caspase‐8 acting as an upstream activator. Activated caspase‐8 initiates the release of cytochrome c during TQ‐induced apoptosis. Overall, these results offer a potential mechanism for TQ‐induced apoptosis in p53‐null HL‐60 cancer cells. © 2005 Wiley‐Liss, Inc.
Significance of HDMX‐S (or MDM4) mRNA splice variant overexpression and HDMX gene amplification on primary soft tissue sarcoma prognosis
Authors: Bartel Frank , Schulz Jördis , Böhnke Anja , Blümke Karen , Kappler Matthias , Bache Matthias , Schmidt Hannelore , Würl Peter , Taubert Helge , Hauptmann Steffen
Published: May 2005

The product of the HDMX (or MDM4) gene is structurally related to the MDM2 oncoprotein and is also capable of interacting with the tumor suppressor protein p53. The aim of our study was to determine the amplification status of the HDMX gene and the expression of the HDMX mRNA (particularly that of the HDMX‐S splice variant) in soft‐tissue sarcomas (STS). Patients with STS were evaluated for the status of HDMX gene amplification (n = 66) and HDMX‐S mRNA expression (n = 57) within their tumors. DNA, total RNA and protein were isolated from frozen tumor tissue. We determined that the HDMX‐S splice variant transcript was predominant in a subset (14%) of tumor samples and that its expression was correlated with decreased patient survival (15 vs. 53 months, p < 0.0001, log‐rank test) and with a 17‐fold increased risk of a tumor‐related death (p < 0.0001, multivariate Cox's regression model). The tumors from these patients also expressed elevated levels of HDMX‐S protein. The HDMX gene was amplified in 17% of STSs, and the gene amplification was associated with poor prognosis (RR = 6.5, p < 0.0001). There was no correlation between the HDMX gene amplification and overexpression of the HDMX‐S splice variant. In summary, our data indicate that both the overexpression of the HDMX‐S transcript as well as HDMX gene amplification are important prognostic markers for STS. © 2005 Wiley‐Liss, Inc.
Cell separation between mesenchymal progenitor cells through porous polymeric membranes
Authors: Higuchi Akon , Shindo Yosuke , Gomei Yumiko , Mori Taisuke , Uyama Taro , Umezawa Akihiro
Published: May 2005

This study investigates the separation of two types of marrow stromal cells, KUSA‐A1 osteoblasts and H‐1/A preadipocytes, by filtration through various porous polymeric membranes. It was found that KUSA‐A1 permeates better than H‐1/A cells through 12‐μm polyurethane foaming membranes. This appears to be due to the relatively smaller cell size of KUSA‐A1 cells. In addition, when feed solutions containing suspensions of either cell type or a mixture of the two were used, the permeation ratio was relatively low (< 6%) through polyurethane and surface‐modified polyurethane foaming membranes. It was also found that there was some degree of separation between KUSA‐A1 and H‐1/A cells (separation factor = 1.8) with nylon‐net filter membranes, but no separation was obtained when filters made of nonwoven fabrics or silk screens were used. This ability of the nylon‐net filter membranes to separate the two cell types was due to a sieving effect that results from an optimal pore size. Finally, permeation of a solution of human serum albumin through the membrane following filtration of the cells did not result in a separation of cells in the recovery solution. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Quantitative analysis of monomer vapor release from two‐solution bone cement by using a novel FTIR technique
Authors: Merkhan Imad K. , Hasenwinkel Julie M. , Gilbert Jeremy L.
Published: May 2005

Methyl methacrylate monomer can evaporate from bone cement to reach cytotoxic levels of concentrations in the implant bed of total joint prosthesis. Therefore, this study was performed by using a novel Fourier transform infrared spectroscopy method to quantify the release of monomer vapor from experimental two‐solution bone cement in vitro during polymerization, to examine the effect of surface area versus cement mass, and to explore the effect of initiation chemistry. The results revealed that monomer vapor release is a surface phenomenon. In addition, initiation chemistry plays a major role in controlling the reaction time, and therefore heat concentration and dissipation, which resulted in a higher absorbance peak as initiation chemicals concentration increased. It was concluded that using the FTIR to monitor MMA vapors is an effective technique to obtain quantitative information about monomer vapor release from bone cements during polymerization and provides insight on the polymerization kinetics of two‐solution acrylic bone cement. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Strategies for increasing the efficiency of a genetic algorithm for the structural optimization of nanoalloy clusters
Authors: Lloyd Lesley D. , Johnston Roy L. , Salhi Said
Published: May 2005

An improved genetic algorithm (GA) is described that has been developed to increase the efficiency of finding the global minimum energy isomers for nanoalloy clusters. The GA is optimized for the example Pt12Pd12, with specific investigation of: the effect of biasing the initial population by seeding; the effect of removing specified clusters from the population (“predation”); and the effect of varying the type of mutation operator applied. These changes are found to significantly enhance the efficiency of the GA, which is subsequently demonstrated by the application of the best strategy to a new cluster, namely Pt19Pd19. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1069–1078, 2005
Role of the surface heterogeneity in adsorption of hydrogen ions on metal oxides: Theory and simulations
Authors: Zarzycki Piotr , Szabelski Paweł , Charmas Robert
Published: May 2005

In this article we study the effect of energetic heterogeneity of a crystalline surface on the adsorption of hydrogen ions (protons) from the liquid phase. In particular, we examine the influence of the shape of the adsorption energy distribution on the equilibrium isotherms of hydrogen ions. To that purpose, a few popular distribution functions, including rectangular, exponential, and asymmetric Gaussian are considered. Additionally, multimodal distribution functions, which may correspond to the adsorption on different crystal planes of the oxide, are also used. Lateral interactions between adsorbed charges are modeled using the potential function proposed by Borkovec et al., which accounts also for polarization of the liquid medium. The results presented here are obtained using both Monte Carlo (MC) simulations and theoretical calculations involving Mean Field Approximation (MFA). They indicate that increased energetic heterogeneity of the adsorbing surface may, in general, considerably change the behavior of the adsorption isotherms, regardless of the assumed distribution function. It is also shown that the predictions of the proposed theory are consistent with the data obtained from the MC simulations. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1079–1088, 2005
Triangular embeddings of complete graphs (neighborly maps) with 12 and 13 vertices
Authors: Ellingham M. N. , Stephens Chris
Published: May 2005

In this paper, we describe the generation of all nonorientable triangular embeddings of the complete graphs K12 and K13. (The 59 nonisomorphic orientable triangular embeddings of K12 were found in 1996 by Altshuler, Bokowski, and Schuchert, and K13 has no orientable triangular embeddings.) There are 182,200 nonisomorphic nonorientable triangular embeddings for K12, and 243,088,286 for K13. Triangular embeddings of complete graphs are also known as neighborly maps and are a type of twofold triple system. We also use methods of Wilson to provide an upper bound on the number of simple twofold triple systems of order n, and thereby on the number of triangular embeddings of Kn. We mention an application of our results to flexibility of embedded graphs. © 2005 Wiley Periodicals, Inc. J Combin Designs
The spectrum of cyclic BSA(ν, 3, λ; α) with α = 2, 3
Authors: Zhang Jing , Chang Yanxun
Published: May 2005

Balanced sampling plans excluding contiguous units (or BSEC) were first introduced by Hedayat, Rao, and Stufken in 1988. In this paper, we generalize the concept of a cyclic BSEC to a cyclic balanced sampling plan to avoid the selection of adjacent units (or CBSA for short) and use Langford and extended Langford sequences to construct a cyclic BSA(ν, 3, λ; α) with α = 2, 3. We finally establish the necessary and sufficient conditions for the existence of a cyclic BSA(ν, 3, λ; α) where α = 2, 3. © 2005 Wiley Periodicals, Inc. J Combin Designs.
A miniaturized nebulization catheter for improved gene delivery to the mouse lung
Authors: Köping‐Höggård Magnus , Issa Mohamed M. , Köhler Tamara , Tronde Ann , Vårum Kjell M. , Artursson Per
Published: May 2005

Background

The available methods for administration of gene delivery systems to the lungs of small animals via nebulization have several drawbacks. These include lack of control over the delivered dose and a negative impact on the stability of the formulation. This paper describes a new nebulization catheter device for the administration of plasmid‐based gene delivery systems (polyplexes) as aerosols to the mouse lung in vivo.

Methods

The physical stability of naked pDNA and polyplexes formulated with chitosan oligomers and PEI was examined following nebulization with the catheter device. We also examined the in vitro transfection efficiency of the polyplexes recovered after nebulization. Lung distribution and gene expression after administration of the selected gene delivery systems to the mouse lung were also investigated.

Results

In contrast to previously described nebulization methods, the structural integrity of the unprotected naked pDNA was maintained following nebulization by the catheter device, which indicates relatively mild nebulization conditions. In addition, the nebulization procedure did not affect the physical stability of the formulated polyplexes. Small volumes of the pDNA aerosol (10–20 µl) were delivered in a highly controlled and reproducible manner. The aerosol droplet size varied with the molecular weight of the polycations. Aerosol delivery via this method resulted in improved lung distribution of pDNA polyplexes and a six‐fold increase in the efficiency of gene delivery in vivo over that seen with the commonly used intratracheal instillation method.

Conclusion

The use of the nebulization catheter device provides a promising alternative for aerosol gene delivery to the mouse lung. Copyright © 2005 John Wiley & Sons, Ltd.
Diffusion tensor fractional anisotropy of the normal‐appearing seven segments of the corpus callosum in healthy adults and relapsing‐remitting multiple sclerosis patients
Authors: Hasan Khader M. , Gupta Rakesh K. , Santos Rafael M. , Wolinsky Jerry S. , Narayana Ponnada A.
Published: May 2005

Purpose

To investigate the utility of whole‐brain diffusion tensor imaging (DTI) in elucidating the pathogenesis of multiple sclerosis (MS) using the normal‐appearing white matter (NAWM) of the corpus callosum (CC) as a marker of occult disease activity.

Materials and Methods

A high signal‐to‐noise ratio (SNR) and optimized entire brain DTI data were acquired in 26 clinically‐definite relapsing and remitting multiple sclerosis (RRMS) patients and 32 age‐matched healthy adult controls. The fractional anisotropy (FA) values of seven functionally distinct regions in the normal‐appearing CC were compared between patients and controls.

Results

This study indicates that 1) there was a gender‐independent FA heterogeneity of the functionally specialized CC segments in normal volunteers; 2) FA in the MS group was significantly decreased in the anterior (P = 0.0039) and posterior (P = 0.0018) midbody subdivisions of the CC, possibly due to a reduction of small‐caliber axons; and 3) the FA of the genu of the CC was relatively intact in the MS patients compared to the healthy age‐matched controls (P = 0.644), while the splenium showed an insignificant trend of reduced FA values (P = 0.248). The decrease in FA in any of the CC subdivisions did not correlate with disease duration (DD) or the expanded disability status scale (EDSS) score.

Conclusion

The preliminary results are consistent with published histopathology and clinical studies on MS, but not with some published DTI reports. This study provides insights into the pathogenesis of MS, and the role played by compromised axonal integrity in this disease. J. Magn. Reson. Imaging 2005;21:735–743. © 2005 Wiley‐Liss, Inc.
Prognostic value of dynamic MR imaging for non‐small‐cell lung cancer patients after chemoradiotherapy
Authors: Ohno Yoshiharu , Nogami Munenobu , Higashino Takanori , Takenaka Daisuke , Matsumoto Sumiaki , Hatabu Hiroto , Sugimura Kazuro
Published: May 2005

Purpose

To determine the prognostic value of dynamic MRI for non‐small‐cell lung cancer (NSCLC) patients after chemoradiotherapy.

Materials and Methods

A total of 114 consecutive patients with NSCLC underwent dynamic MRI after chemoradiotherapy. The patients were divided into two groups (local control (n = 22) and local failure (n = 92)) according to the presence of local recurrence. From the signal intensity‐time course curve in each subject, the maximum relative enhancement ratio and slope of enhancement were calculated, and compared between two groups by Student's t‐test. To determine the feasible threshold values of both MR indexes for group differentiation, ROC‐based positive tests were performed. Finally, the Kaplan‐Meier survival curves of each group divided by the adapted threshold value were compared by log‐rank test.

Results

The maximum relative enhancement ratio and the slope of enhancement in the local control group were significantly lower than those in the local failure group (P < 0.05). Using 0.08/sec as the threshold value of the slope of enhancement, the sensitivity and specificity for differentiation between the two groups were 90.9% and 91.3%, respectively. When the slope of enhancement was adopted for estimation of prognosis after therapy, the mean survival period of the slope of enhancement ≤ 0.08/sec group was significantly longer than that seen in the group with a slope of enhancement > 0.08/sec (P < 0.0001).

Conclusion

Dynamic MRI has potential prognostic value for NSCLC patients after chemoradiotherapy. J. Magn. Reson. Imaging 2005;21:775–783. © 2005 Wiley‐Liss, Inc.
Diffusion‐weighted MRI of the lung with hyperpolarized helium‐3: A study of reproducibility
Authors: Morbach Andreas E. , Gast Klaus K. , Schmiedeskamp Jörg , Dahmen Anja , Herweling Annette , Heussel Claus P. , Kauczor Hans‐Ulrich , Schreiber Wolfgang G.
Published: May 2005

Purpose

To determine the reproducibility of several parameters of the ADC measurement by calculating the scan‐to‐scan intrasubject variability.

Materials and Methods

Measurements were performed using a gradient‐echo sequence with a bipolar gradient for diffusion weighting (b = 3.89 sec/cm2). Five patients with pulmonary emphysema, and six healthy‐lung volunteers were included in the study. Images were acquired after inspiration of3He during a single inspiratory breath‐hold. To assess the reproducibility, the measurement was performed twice (time between measurements = 20 minutes) without repositioning the subjects. Analysis was performed on the basis of region‐of‐interest (ROI) analysis and global lung ADC histograms.

Results

The mean ADC of a ROI varied by 5.1% between two measurements for volunteers and by 6.1% for patients. In the global evaluation, the 75th percentile demonstrated the best reproducibility (2%), while other parameters showed variations up to 12%. Only the variation of the standard deviation (SD) and the measure of homogeneity of the ADC map showed a significant difference between patients and volunteers.

Conclusion

Diffusion‐weighted imaging (DWI) is a well‐reproducible method for assessing the lung microstructure. J. Magn. Reson. Imaging 2005;21:765–774. © 2005 Wiley‐Liss, Inc.
High‐dose Gd‐DTPA vs. Bis‐Gd‐mesoporphyrin for monitoring laser‐induced tissue necrosis
Authors: Bremer Christoph , Bankert Joerg , Filler Timm , Ebert Wolfgang , Tombach Bernd , Reimer Peter
Published: May 2005

Purpose

To compare Bis‐Gd‐mesoporphyrin (Bis‐Gd‐MP), a contrast agent with a reported high affinity to necrotic tissue, with high‐dose gadopentate dimeglumin (Gd‐DTPA) for defining laser‐induced muscle and liver necrosis by contrast‐enhanced (CE) MRI.

Materials and Methods

Laser‐induced interstitial thermotherapy (LITT) was performed in the muscle and liver tissue of New Zealand White rabbits (1500 J and 2100 J; n = 80 lesions). The animals were randomly assigned to a group that received 0.3 mmol/kg bw Gd‐DTPA or a group that received 0.05 mmol/kg bw Bis‐Gd‐MP. Following contrast injection, dynamic MRI was performed on muscle lesions with a T1‐weighted, two‐dimensional, fast low‐angle shot (FLASH) sequence. The liver and muscle lesions were then repeatedly imaged for six hours after contrast injection using a T1‐weighted spin‐echo (SE) sequence. Central and peripheral lesion enhancement was determined and correlated with gross pathology and microscopy findings.

Results

Both contrast agents allowed precise determination of lesion diameters with an average accuracy of 6.8% ± 1.3%. Rim enhancement during dynamic MRI was superior for Gd‐DTPA (P < 0.001) and revealed slightly higher lesion diameters compared to the results of follow‐up MR studies. A persistent enhancement of necrotic liver and muscle tissue was observed for both contrast agents throughout the observation period, suggesting that simple diffusion‐type processes may underlie the supposed affinity of Bis‐Gd‐MP for tissue necrosis.

Conclusion

Bis‐Gd‐MP and Gd‐DTPA are equally well suited for postinterventional lesion assessment in LITT. J. Magn. Reson. Imaging 2005;21:801–808. © 2005 Wiley‐Liss, Inc.
Region‐growing segmentation of brain vessels: An atlas‐based automatic approach
Authors: Passat Nicolas , Ronse Christian , Baruthio Joseph , Armspach Jean‐Paul , Maillot Claude , Jahn Christine
Published: May 2005

Purpose

To propose an atlas‐based method that uses both phase and magnitude images to integrate anatomical information in order to improve the segmentation of blood vessels in cerebral phase‐contrast magnetic resonance angiography (PC‐MRA).

Material and Methods

An atlas of the whole head was developed to store the anatomical information. The atlas divides a magnitude image into several vascular areas, each of which has specific vessel properties. It can be applied to any magnitude image of an entire or nearly entire head by deformable matching, which helps to segment blood vessels from the associated phase image. The segmentation method used afterwards consists of a topology‐preserving, region‐growing algorithm that uses adaptive threshold values depending on the current region of the atlas. This algorithm builds the arterial and venous trees by iteratively adding voxels that are selected according to their grayscale value and the variation of values in their neighborhood. The topology preservation is guaranteed because only simple points are selected during the growing process.

Results

The method was performed on 40 PC‐MRA images of the brain. The results were validated using maximum‐intensity projection (MIP) and three‐dimensional surface rendering visualization, and compared with results obtained with two non‐atlas‐based methods.

Conclusion

The results show that the proposed method significantly improves the segmentation of cerebral vascular structures from PC‐MRA. These experiments tend to prove that the use of vascular atlases is an effective way to optimize vessel segmentation of cerebral images. J. Magn. Reson. Imaging 2005;21:715–725. © 2005 Wiley‐Liss, Inc.
Feasibility of in vivo, multicontrast‐weighted MR imaging of carotid atherosclerosis for multicenter studies
Authors: Chu Baocheng , Zhao Xue‐Qiao , Saam Tobias , Yarnykh Vasily L. , Kerwin William S. , Flemming Kelly D. , Huston John , Insull William , Morrisett Joel D. , Rand Scott D. , DeMarco Kevin J. , Polissar Nayak L. , Balu Niranjan , Cai Jianming , Kampschulte Annette , Hatsukami Thomas S. , Yuan Chun
Published: May 2005

Purpose

To test the image quality (ImQ) and interscan coverage of MRI for measuring carotid atherosclerosis across multiple centers.

Materials and Methods

Thirty‐nine subjects from five clinical sites (site 1: n = 11; site 2: n = 16; site 3: n = 2; site 4: n = 3; site 5: n = 7) were imaged on GE 1.5T scanners using a standardized carotid imaging protocol with five weightings (T1, proton density (PD), T2, time‐of‐flight (TOF), and contrast‐enhanced (CE) T1). MR technologists from the five sites received comprehensive protocol training. A maximum coverage of 24 mm (12 slices) was designed for each of four scans (baseline and at four, eight, and 13 weeks). The adequacy of coverage was calculated as the percentage of arteries with at least six slices matched across all four scans. ImQ was evaluated using an established five‐point scale for each image. ImQ ≥ 3 was considered acceptable for image analysis.

Results

Across five sites, the mean ImQ was 3.4–4.2 for T1W, 3.6–4.4 for CE‐T1W, 3.4–4.2 for PDW, 3.3–4.2 for T2W, and 3.4–4.0 for TOF. The mean ImQ per site was 3.5–4.2. All sites generated at least six‐slice coverage (mean = 8.0–9.1) for all index carotid arteries.

Conclusion

The ImQ and coverage values were comparable among clinical sites using a standardized carotid imaging protocol. With comprehensive protocol training, carotid MRI is technically feasible for use in multicenter studies. J. Magn. Reson. Imaging 2005;21:809–817. © 2005 Wiley‐Liss, Inc.
Breast MRI findings after modified radical mastectomy and transverse rectus abdominis myocutaneous flap in patients with breast cancer
Authors: Kang Bong Joo , Jung Jung Im , Park Changsook , Park Woo Chan , Jeon Hae Myung , Hahn Seong Tai , Lee Jae Mun
Published: May 2005

Purpose

To evaluate the MRI findings in breast cancer patients who had undergone a modified radical mastectomy (MRM) and a transverse rectus abdominis myocutaneous (TRAM) flap.

Materials and Methods

MRI was performed on 20 patients who had been diagnosed with breast cancer and had undergone an MRM and TRAM flap. The results were examined in terms of MRI's ability to detect the flap and assess possible postoperative changes and recurrence. In addition, MRI images of the opposite breast were analyzed. Follow‐up examinations were carried out on 11 patients, and all changes were assessed.

Results

The flap was clearly visualized by MRI in all of the patients. The signal intensity of the flap was equivalent to that of fat. The contact zone between the TRAM flap and the mastectomy site was enhanced after contrast infusion. Postoperative changes, such as skin thickening (n = 20), edema (n = 2), fluid collection (n = 3), hematoma (n = 1), and fat necrosis (n = 3), were detected. In two patients, artificially inserted fat tissue was identified. On the MRI of the opposite breast, enhancing lesions were detected in seven patients. In one patient with this finding, ductal carcinoma in situ was diagnosed. On the follow‐up MRI, a decrease in skin thickening, fat necrosis, and hematoma was detected.

Conclusion

MRI is an effective method for lesion detection and evaluation of postoperative changes after MRM and TRAM flap, as well as for evaluation of the opposite breast. J. Magn. Reson. Imaging 2005;21:784–791. © 2005 Wiley‐Liss, Inc.
Anthropometric data for magnetic resonance imaging of the carotid bifurcation
Authors: Thomas Jonathan B. , Jong Lisa , Spence J. David , Wasserman Bruce A. , Rutt Brian K. , Steinman David A.
Published: May 2005

Purpose

To provide anthropometric data applicable to the design of protocols for high‐resolution magnetic resonance imaging (MRI) of the carotid bifurcation, particularly those aimed at elucidating the role of local factors in carotid atherogenesis.

Materials and Methods

Axial black‐blood MR images of the carotid bifurcation were acquired from 25 young, healthy volunteers and 25 older, asymptomatic patients, from which were measured a variety of quantities related to the orientation and placement of the bifurcation within the neck.

Results

Descriptive statistics were obtained for the following quantities: separation of the bifurcation apices within (57.8 ± 6.7 mm) and between (4.9 ± 4.1 mm) axial slices; orientation of the bifurcation within the axial plane (31.7 ± 26.9°), and of the common carotid artery (CCA) relative to the sagittal (7.5 ± 7.1°) and coronal (7.9 ± 7.8°) planes; depth of the bifurcation from the skin surface (29.5 ± 7.2 mm); and neck width (125.9 ± 14.4 mm).

Conclusion

In most cases, both carotid arteries may be captured, without aliasing, within a 12‐cm field‐of‐view axial image; however, the two apices will rarely be captured within the same axial slice. The CCA is significantly oblique to the body axis, but at angles sufficiently acute to permit the use of axial slices. Finally, a significant linear relationship between neck width and carotid depth may be used to inform radio frequency (RF) coil selection prior to scanning a subject, and hence facilitate optimal imaging in light of the wide anatomic variations observed. J. Magn. Reson. Imaging 2005;21:845–849. © 2005 Wiley‐Liss, Inc.
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

Purpose

To 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 Methods

Rats 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.

Results

The 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.

Conclusion

Map‐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

Purpose

To determine the effect of respiratory phase on the T1 values of the entire lung.

Materials and Methods

We 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.

Results

The 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.

Conclusion

T1 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

Purpose

To 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 Methods

Orthotopic 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.

Results

All 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.

Conclusion

Orthotopic 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

Purpose

To 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 Methods

A 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.

Results

It 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.

Conclusion

Analysis 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

Purpose

To determine whether tissue edema changes gadolinium‐diethylenetriamine pentaacetic acid (Gd‐DTPA)‐enhanced T1 relaxation times of the viable myocardium.

Materials and Methods

A 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).

Results

Tissue 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.

Conclusion

Tissue 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

Purpose

To 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 Methods

A 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.

Results

Postcontrast 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.

Conclusion

The 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

Purpose

To 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 Methods

Sagittal 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.

Results

On 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.

Conclusion

The 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

Purpose

To 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 Methods

A 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.

Results

ADCs 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).

Conclusion

The 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

Purpose

To 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 Methods

The 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.

Results

The 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.

Conclusion

Brain 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

Purpose

To examine the possibility of performing high‐resolution MRI (microneurography) on peripheral nerves.

Materials and Methods

A 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.

Results

The 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).

Conclusion

The 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

Purpose

To 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 Methods

Using 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.

Results

Refocused 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.

Conclusion

Single‐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

Background and Objectives

Some 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 Methods

We 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.

Results

PWSs previously refractory to the shorter pulse duration lasers responded well to treatment, as did PWSs not previously treated with any laser.

Conclusions

The 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

Proton 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.