bluuebunny/crossref_metadata_2025 huggingface dataset:
Survival versus apoptotic 17β‐estradiol effect: Role of ERα and ERβ activated non‐genomic signaling
Authors: Acconcia Filippo , Totta Pierangela , Ogawa Sumito , Cardillo Irene , Inoue Satoshi , Leone Stefano , Trentalance Anna , Muramatsu Masami , Marino Maria
Published: September 2004

The capability of 17β‐estradiol (E2) to induce the non‐genomic activities of its receptors (ERα and ERβ) and to evoke different signaling pathways committed to the regulation of cell proliferation has been analyzed in different cell cancer lines containing transfected (HeLa) or endogenous (HepG2, DLD1) ERα or ERβ. In these cell lines, E2 induced different effects on cell growth/apoptosis in dependence of ER isoforms present. The E2–ERα complex rapidly activated multiple signal transduction pathways (i.e., ERK/MAPK, PI3K/AKT) committed to both cell cycle progression and apoptotic cascade prevention. On the other hand, the E2–ERβ complex induced the rapid and persistent phosphorylation of p38/MAPK which, in turn, was involved in caspase‐3 activation and cleavage of poly(ADP‐ribose)polymerase, driving cells into the apoptotic cycle. In addition, the E2–ERβ complex did not activate any of the E2–ERα‐activated signal molecules involved in cell growth. Taken together, these results demonstrate the ability of ERβ isoform to activate specific signal transduction pathways starting from plasma membrane that may justify the effect of E2 in inducing cell proliferation or apoptosis in cancer cells. In particular this hormone promotes cell survival through ERα non‐genomic signaling and cell death through ERβ non‐genomic signaling. © 2004 Wiley‐Liss, Inc.
Role of cell surface heparan sulfate proteoglycans in endothelial cell migration and mechanotransduction
Authors: Moon James J. , Matsumoto Melissa , Patel Shyam , Lee Luke , Guan Jun‐Lin , Li Song
Published: September 2004

Endothelial cell (EC) migration is critical in wound healing and angiogenesis. Fluid shear stress due to blood flow plays an important role in EC migration. However, the role of EC surface heparan sulfate proteoglycans (HSPGs) in EC adhesion, migration, and mechanotransduction is not well understood. Here, we investigated the effects of HSPG disruption on the adhesion, migration, and mechanotransduction of ECs cultured on fibronectin. We showed that disruption of HSPGs with heparinase decreased EC adhesion rate by 40% and adhesion strength by 33%. At the molecular level, HSPG disruption decreased stress fibers and the size of focal adhesions (FAs), increased filopodia formation, and enhanced EC migration. Under flow condition, heparinase treatment increased EC migration speed, but inhibited shear stress‐induced directionality of EC migration and the recruitment of phosphorylated focal adhesion kinase in the flow direction, suggesting that HSPGs are important for sensing the direction of shear stress. In addition, decreasing cell adhesion by lowering fibronectin density enhanced EC migration under static and flow condition, but did not affect the directional migration of ECs under flow. Based on our results, we propose that HSPGs play dual roles as mechanotransducer on the EC surface: (1) HSPGs–matrix interaction on the abluminal surface regulates EC migration speed through an adhesion‐dependent manner, and (2) HSPGs without binding to matrix (e.g., on the luminal surface) are involved in sensing the direction of flow through an adhesion‐independent manner. © 2004 Wiley‐Liss, Inc.
CHK1 affects cell sensitivity to microtubule‐targeted drugs
Authors: Ren Qing , Liu Ronghua , Dicker Adam , Wang Ya
Published: September 2004

Microtubules are the target of many anticancer drugs. Understanding the mechanism by which cells respond to different microtubule‐targeted drugs is important to resolve the drug resistance and to gain better tumor control. We report here for the first time that CHK1, an essential protein in mammalian cells, affects cell sensitivity to microtubule‐targeted drugs. By using a pair of transformed rat fibroblast cell lines, we show that compared with their counterpart B4 cells, A1‐5 cells with higher CHK1 expression are more resistant to taxotere, a microtubule stabilizer, but are more sensitive to nocodazole, a microtubule destabilizer. We also show that the altered sensitivities of A1‐5 cells to either taxotere or to nocodazole are related to the lesser microtubule‐formation in the cells. In addition, we show that the altered drug sensitivities and less microtubules‐formation shown in A1‐5 cells could be efficiently reversed by Chk1 siRNA. Taken together, these results indicate that CHK1 is one of the factors affecting cell resistance to taxotere and sensitiveness to nocodazole, suggesting that CHK1 is involved in affecting microtubule dynamics and could be inhibited for taxotere sensitization in CHK1 highly expressed tumor cells. © 2004 Wiley‐Liss, Inc.
Cell transformation byHerpesvirus saimiri
Authors: Tsygankov Alexander Y.
Published: September 2004

Herpesvirus saimiri(Saimiriine herpesvirus‐2), a γ2‐herpesvirus (rhadinovirus) of non‐human primates, causes T‐lymphoproliferative diseases in susceptible organisms and transforms human and non‐human T lymphocytes to continuous growth in vitro in the absence of stimulation. T cells transformed byH. saimiriretain many characteristics of intact T lymphocytes, such as the sensitivity to interleukin‐2 and the ability to recognize the corresponding antigens. As a result,H. saimiriis widely used in immunobiology for immortalization of various difficult‐to‐obtain and/or ‐to‐maintain T cells in order to obtain useful experimental models. In particular,H. saimiri‐transformed human T cells are highly susceptible to infection with HIV‐1 and ‐2. This makes them a convenient tool for propagation of poorly replicating strains of HIV, including primary clinical isolates. Therefore, the mechanisms mediating transformation of T cells byH. saimiriare of considerable interest. A single transformation‐associated protein, StpA or StpB, mediates cell transformation byH. saimiristrains of group A or B, respectively. Strains of group C, which exhibit the highest oncogenic potential, have two proteins involved in transformation—StpC and Tip. Both proteins have been shown to dramatically affect signal transduction pathways leading to the activation of crucial transcription factors. This review is focused on the biological effects and molecular mechanisms of action of proteins involved inH. saimiri‐dependent transformation. © 2004 Wiley‐Liss, Inc.
Adenovirus‐mediated overexpression of tissue inhibitor of metalloproteinases‐1 in the liver: efficient protection against T‐cell lymphoma and colon carcinoma metastasis
Authors: Elezkurtaj Sefer , Kopitz Charlotte , Baker Andrew H. , Perez‐Cantó Alejandra , Arlt Matthias J. E. , Khokha Rama , Gansbacher Bernd , Anton Martina , Brand Karsten , Krüger Achim
Published: September 2004

Background

Matrix metalloproteinases (MMPs) are critical for metastasis of tumor cells. Tissue inhibitor of metalloproteinases‐1 (TIMP‐1), a natural MMP inhibitor, was shown to reduce metastasis in different models. Here, we investigated whether increased TIMP‐1 levels in the liver achieved by adenoviral gene transfer will effectively inhibit liver metastasis of two independent tumor cell lines.

Method

TIMP‐1 was transferred with adenoviral vectors into the livers of DBA/2 and Balb/c mice, which were subsequently challenged by hematogenous experimental metastases of the T‐cell lymphoma cell line L‐CI.5s or the colorectal carcinoma cell line CT‐26, respectively.

Results

MMP‐9 expression in the liver was induced upon metastasis in both tumor types. Adenoviral gene transfer led to high transduction efficacy as indicated by lacZ expression in 60% of hepatocytes. TIMP‐1, a key inhibitor of MMP‐9, was expressed at 105‐fold higher levels by adenoviral gene transfer as compared with levels achieved in TIMP‐1 transgenic mice, previously shown to be inefficient to reduce T‐cell lymphoma metastasis. High local and systemic (serum) levels of TIMP‐1 led to substantial (94%) reduction of T‐cell lymphoma and colorectal carcinoma (73%) experimental liver metastasis.

Conclusions

Adenoviral gene transfer led to systemic and local TIMP‐1 levels sufficient to inhibit metastasis of a highly aggressive T‐cell lymphoma, pointing at the requirement of threshold levels for effective anti‐metastatic efficacy. This approach was also efficient in a colon carcinoma solid tumor model. We propose that viral gene transfer of TIMP‐1 can provide a suitable defense strategy to prevent metastatic spread to the liver. Copyright © 2004 John Wiley & Sons, Ltd.
Usefulness of the calculated apparent diffusion coefficient value in the differential diagnosis of retroperitoneal masses
Authors: Nakayama Tomohiro , Yoshimitsu Kengo , Irie Hiroyuki , Aibe Hitoshi , Tajima Tsuyoshi , Shinozaki Kenji , Nishie Akihiro , Asayama Yoshiki , Kakihara Daisuke , Matsuura Shuji , Honda Hiroshi
Published: September 2004

Purpose

To elucidate whether or not the apparent diffusion coefficient (ADC) values calculated from echo‐planar diffusion‐weighted (EPDW) MR images are useful in the differential diagnosis of retroperitoneal masses.

Materials and Methods

In 50 patients with known retroperitoneal masses, EPDW images were performed with b‐factors of 0–1100 seconds/mm2. The final histologic diagnoses of these lesions were as follows: 12 malignant lymphomas, four other malignant mesenchymal neoplasms, 25 malignant epithelial neoplasms, seven benign mesenchymal neoplasms, and two nonneoplastic lesions. The ADC values obtained for the solid portion of the lesions were used to represent each lesion, and the values of the histologic groups were compared.

Results

The respective value of ADC for 12 malignant lymphomas, four other mesenchymal neoplasms, seven benign mesenchymal neoplasms, and two nonneoplastic lesions were as follows: 0.66 ± 0.26, 1.26 ± 0.50, 0.90 ± 0.20, 1.87 ± 0.48, 1.32 ± 0.20 × 10−3 mm2/second. The ADC value of the malignant lymphoma was significantly lower than that of the other malignant mesenchymal lesions, and was also lower than the ADC of the benign lesions. The ADC value of the malignant epithelial neoplasms was lower than that of the benign mesenchymal tumors. The ADC values of the malignant and benign lesions were 0.94 ± 0.30 and 1.75 ± 0.49 × 10−3 mm2/second, respectively, which also demonstrated a significant difference.

Conclusion

ADC values calculated from EPDW MR images may provide useful information in the differential diagnosis of retroperitoneal masses. J. Magn. Reson. Imaging 2004;20:735–742. © 2004 Wiley‐Liss, Inc.
Assessment of lung perfusion impairment in patients with pulmonary artery‐occlusive and chronic obstructive pulmonary diseases with noncontrast electrocardiogram‐gated fast‐spin‐echo perfusion MR imaging
Authors: Ogasawara Nobuhiko , Suga Kazuyoshi , Zaki Mohammed , Okada Munemasa , Kawakami Yasuhiko , Matsunaga Naofumi
Published: September 2004

Purpose

To evaluate the ability of noncontrast electrocardiogram (ECG)‐gated fast‐spin‐echo (FSE) perfusion MR images for defining regional lung perfusion impairment, as compared with technetium (Tc)‐99m macroaggregated albumin (MAA) single‐photon emission computed tomography (SPECT) images.

Materials and Methods

After acquisition of ECG‐gated multiphase FSE MR images during cardiac cycles at selected lung levels in nine healthy volunteers, 11 patients with pulmonary artery–occlusive diseases, and 15 patients with chronic obstructive pulmonary diseases (COPD), the subtracted perfusion‐weighted (PW) MR images were obtained from the two‐phase images of the minimum lung signal intensity (SI) during systole and the maximum SI during diastole, and were compared with SPECT images.

Results

ECG‐gated PW images showed uniform but posture‐dependent perfusion gradient in normal lungs and visualized the various sizes of perfusion defects in affected lungs. These defect sites were nearly consistent with those on SPECT images, with a significant correlation for the affected‐to‐unaffected perfusion contrast (r = 0.753; P < 0.0001). These MR images revealed that the pulmonary arterial blood flow in the affected areas of COPD was relatively preserved as compared with pulmonary artery–occlusive diseases, and also showed significant decrease in blood flow, even in the areas with homogeneous perfusion on SPECT images in patients with focal pulmonary emphysema.

Conclusion

This noninvasive MR technique allows qualitative and quantitative assessment of lung perfusion, and may better characterize regional perfusion impairment in pulmonary artery–occlusive diseases and COPD. J. Magn. Reson. Imaging 2004;20:601–611. © 2004 Wiley‐Liss, Inc.
Ferritin‐induced relaxation in tissues: An in vitro study
Authors: Gossuin Yves , Burtea Carmen , Monseux Anne , Toubeau Gérard , Roch Alain , Muller Robert N. , Gillis Pierre
Published: September 2004

Purpose

To study in vitro the proton relaxation induced in tissues by ferritin, the iron‐storing protein of mammals.

Materials and Methods

Nuclear magnetic relaxation dispersion (NMRD) profiles of liver and spleen from control and iron‐overloaded mice are compared with NMRD profiles of ferritin and Fercayl®—a ferritin‐like akaganeite particle—in aqueous solutions or in 1% agarose gel.

Results

The relaxation of water protons induced by ferritin and Fercayl® in 1% agarose gel is comparable with the relaxation of aqueous solutions of the same compounds, but slower than the relaxation of liver and spleen. The gel is not a good model of tissues containing ferritin. The longitudinal NMRD profiles of control and iron‐overloaded liver and spleen are almost identical: ferritin accumulation has only a slight effect on longitudinal relaxation. The transverse NMRD profiles of liver and spleen tissues are linear, but the slope of the linear regression is larger for iron‐loaded organs than for control ones, which is a consequence of a higher ferritin concentration in the former. However, the correlation between the slope of the transverse NMRD profiles and the iron concentration is not very good, probably because transverse relaxation is modified by the clustering of ferritin in cells.

Conclusion

It could be difficult to develop a general technique for the accurate quantification of ferritin‐bound iron by nuclear magnetic resonance or magnetic resonance imaging. J. Magn. Reson. Imaging 2004;20:690–696. © 2004 Wiley‐Liss, Inc.
Prospective registration of human head magnetic resonance images for reproducible slice positioning using localizer images
Authors: Gedat Egbert , Braun Juergen , Sack Ingolf , Bernarding Johannes
Published: September 2004

Purpose

To facilitate assessing brain tumor growth and progression of stroke lesions by reproducible slice positioning in human head magnetic resonance (MR) images, a method for prospective registration is proposed that adjusts the image slice position without moving the patient and with no additional scans.

Materials and Methods

The gradient reference frame of follow‐up examinations was adjusted to achieve the same image slice positioning relative to the patient as in the previous examination. The three‐dimensional geometrical transformation parameters for the gradients were determined using two‐dimensional image registration of three orthogonal localizer images. The method was developed and evaluated using a phantom with arbitrarily adjustable position. Feasibility for in vivo applications was demonstrated with brain MR imaging (MRI) of healthy volunteers.

Results

Standard retrospective registration was used for assessing the quality of the method. The accuracy of the realignment was 0.0 mm ± 1.2 mm and –0.2° ± 0.9° (mean ± SD) in phantom experiments. In 10 examinations of volunteers, misalignments up to 49.2 mm and 21° were corrected. The accuracy of the realignment after prospective registration was 0.1 mm ± 1.5 mm and 0.2° ± 1.5°.

Conclusion

Image‐based prospective registration using localizer images of the pre‐ and postexaminations is a robust method for reproducible slice positioning. J. Magn. Reson. Imaging 2004;20:581–587. © 2004 Wiley‐Liss, Inc.
Functional MRI of the lung using hyperpolarized 3‐helium gas
Authors: van Beek Edwin J.R. , Wild Jim M. , Kauczor Hans‐Ulrich , Schreiber Wolfgang , Mugler John P. , de Lange Eduard E.
Published: September 2004

Lung imaging has traditionally relied on x‐ray methods, since proton MRI is limited to some extent by low proton density in the lung parenchyma and static field inhomogeneities in the chest. The relatively recent introduction of MRI of hyperpolarized noble gases has led to a rapidly evolving field of pulmonary MRI, revealing functional information of the lungs, which were hitherto unattainable. This review article briefly describes the physical background of the technology, and subsequently focuses on its clinical applications. Four different techniques that have been used in various human investigations are discussed: ventilation distribution, ventilation dynamics, and small airway evaluation using diffusion imaging and oxygen uptake assessment. J. Magn. Reson. Imaging 2004;20:540–554. © 2004 Wiley‐Liss, Inc.
Resolution improvement in thick‐slab magnetic resonance digital subtraction angiography using SENSE at 3T
Authors: Summers Paul E. , Kollias Spyros S. , Valavanis Anton
Published: September 2004

Purpose

To evaluate the use of parallel imaging (sensitivity encoding [SENSE]) to improve spatial resolution and achieve sub‐second temporal resolution in fluoroscopic contrast‐enhanced, magnetic resonance digital subtraction angiography (MR‐DSA).

Materials and Methods

A MR‐DSA sequence was optimized on a 3‐T scanner with respect to sampling bandwidth and SENSE acceleration factor subject to the constraints of half‐second acquisition time and 0.6 × 1.2 mm in‐plane resolution. MR‐DSA with and without SENSE acceleration was then evaluated in patients with arterio‐venous malformations (AVMs).

Results

Consistent with previously reported results and theory, SENSE factors greater than two and increasing sampling bandwidth both led to increasing image noise. Compared to lower resolution MR‐DSA images with similar temporal resolution, the SENSE accelerated sequence provided better spatial resolution without notable changes in the contrast enhancement of the vascular territories of the AVMs but was hampered somewhat in the late venous phases by a reconstruction artifact.

Conclusion

SENSE acceleration of MR‐DSA by a factor of two allows improved temporal or spatial resolution without significant loss of image quality. Signal‐to‐noise degradation associated with higher SENSE acceleration factors are likely to necessitate other approaches to further improving resolution in MR‐DSA. Clinically, SENSE accelerated MR‐DSA improves the non‐invasive pre‐ and postoperative depiction of AVM flow dynamics. J. Magn. Reson. Imaging 2004;20:662–673. © 2004 Wiley‐Liss, Inc.
Endorectal diffusion‐weighted imaging in prostate cancer to differentiate malignant and benign peripheral zone tissue
Authors: Hosseinzadeh Keyanoosh , Schwarz Samuel David
Published: September 2004

Purpose

To determine if the apparent diffusion coefficient (ADC) can discriminate benign from malignant peripheral zone (PZ) tissue in patients with biopsy‐proven prostate cancer that have undergone endorectal diffusion‐weighted imaging (DWI) of the prostate.

Materials and Methods

Ten patients with prostate cancer underwent endorectal magnetic resonance imaging (MRI) in addition to DWI. A two‐dimensional grid was placed over the axial images, and each voxel was graded by a 4‐point rating scale to discriminate nonmalignant from malignant PZ tissue based on MR images alone. ADC was then determined for each voxel and plotted for nonmalignant and malignant voxels for the entire patient set. Second, with the radiologist aware of biopsy locations, any previously assigned voxel grade that was inconsistent with biopsy data was regrouped and ADCs were replotted.

Results

For the entire patient set, without and with knowledge of the biopsy data, the mean ADCs for nonmalignant and malignant tissue were 1.61 ± 0.27 and 1.34 ± 0.38 × 10−3 mm2/second (P = 0.002) and 1.61 ± 0.26 and 1.27 ± 0.37 × 10−3 mm2/second (P = 0.0005), respectively.

Conclusion

DWI of the prostate is possible with an endorectal coil. The mean ADC for malignant PZ tissue is less than nonmalignant tissue, although there is overlap in individual values. J. Magn. Reson. Imaging 2004;20:654–661. © 2004 Wiley‐Liss, Inc.
A STAP algorithm approach to fMRI: A simulation study
Authors: Thompson Elizabeth A. , Holland Scott K. , Schmithorst Vincent J.
Published: September 2004

Purpose

To adapt the space‐time adaptive processing (STAP) algorithm, previously developed in the field of sensor array processing and applied to radar signal processing, for use in construction of brain activation maps in functional magnetic resonance imaging (fMRI).

Materials and Methods

STAP is a two‐dimensional filter in which both the spatial and temporal responses are controlled adaptively. It processes space‐time data as a complete spatiotemporal set. Unlike presently used fMRI techniques, STAP locates activated regions both spatially and in frequency.

Results

Computer simulations incorporating actual MRI noise indicate that STAP exhibits a high degree of accuracy in detecting the small signal intensity changes inherent in fMRI.

Conclusion

Because STAP processes space‐time data as a single data matrix, it exhibits potential over currently available fMRI methods in providing a measure of the full spatiotemporal extent of a task‐related activity. J. Magn. Reson. Imaging 2004;20:715–722. © 2004 Wiley‐Liss, Inc.
Algorithms for calculation of kinetic parameters from T1‐weighted dynamic contrast‐enhanced magnetic resonance imaging
Authors: Horsfield Mark A. , Morgan Bruno
Published: September 2004

Purpose

To quantify the errors involved in calculating dynamic parameters (Ktrans and ve) from dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) scans, and to develop alternative analyses to improve accuracy or increase processing speed.

Materials and Methods

This paper presents three different ways of handling the discrete samples of the arterial input and tissue response data with increasing fidelity, with which this continuous arterial input function (AIF) is represented. Also, a new noniterative approach to parameter estimation was developed from one used previously for analysis of radioactive tracer concentrations in radioangiography. The analysis methods were tested using simulated data.

Results

The more sophisticated schemes for data processing give more accurate parameter estimates when data are sparsely sampled, at least for the AIF that we modeled. The noniterative algorithm is very rapid in execution, but was more susceptible to measurement errors.

Conclusion

The improved algorithms presented should be useful when the AIF and tissue response are sparsely sampled. The noniterative approach may be suitable for semiquantitative visualization, or where the AIF and tissue response are sampled accurately and with a small time interval between samples. J. Magn. Reson. Imaging 2004;20:723–729. © 2004 Wiley‐Liss, Inc.
Ascorbate decreases Fabry cerebral hyperperfusion suggesting a reactive oxygen species abnormality: An arterial spin tagging study
Authors: Moore David F. , Ye Frank , Brennan Marie‐Luise , Gupta Surya , Barshop Bruce A. , Steiner Robert D. , Rhead William J. , Brady Roscoe O. , Hazen Stanley L. , Schiffmann Raphael
Published: September 2004

Purpose

To test the hypothesis that reactive oxygen species contribute to the cerebral hyperperfusion in Fabry disease.

Material and Methods

We examined the effect of intravenous injection of ascorbate on cerebral blood flow (CBF) using magnetic resonance arterial spin tagging. Nineteen patients with Fabry disease and 15 control subjects were studied as part of a randomized double‐blind placebo‐controlled trial of enzyme replacement therapy (ERT).

Results

Vertebro‐basilar hyperperfusion was observed in patients with Fabry disease. A decrease in systemic ascorbate levels relative to healthy controls was found in the patients. CBF decreased after ascorbate infusion in both control subjects and patients treated with ERT. The placebo group had a significantly delayed decrease in the CBF response after ascorbate infusion. Myeloperoxidase levels were elevated in Fabry patients, consistent with ongoing inflammatory processes in these patients.

Conclusion

Increased CBF in Fabry disease may be related to increased production of reactive oxygen species, while low plasma ascorbate levels suggests a global redox imbalance. These abnormalities were improved by ERT. These observations have implications regarding oxidative processes contributing to accelerated atherosclerosis in Fabry disease. J. Magn. Reson. Imaging 2004;20:674–683. Published 2004 Wiley‐Liss, Inc.
On flow effects in balanced steady‐state free precession imaging: Pictorial description, parameter dependence, and clinical implications
Authors: Markl Michael , Pelc Norbert J.
Published: September 2004

Purpose

To present a pictorial description of the origin of flow effects in balanced steady‐state free precession (SSFP) imaging that can result in considerable frequency offset‐dependent signal changes originating from outflow of spins that can still contribute to the total SSFP signal (out‐of‐slice contributions), to analyze the parameter dependence and slice broadening associated with outflow effects, and to illustrate clinical implications such as frequency offset‐dependent flow artifacts and spatial misencoding.

Materials and Methods

Computer simulations were used to create a pictorial description of flow effects that illustrates the origin and parameter dependence of the observed signal changes and links their frequency dependency to the phase distribution of spins flowing in and out of the imaging slice. Slice broadening associated with out‐of‐slice contributions and flow‐related signal enhancement was characterized by an effective slice thickness, which depends on flow rate, the T2* decay of signal magnitude from spins that have left the imaging slice, and the ratio of the net out‐of‐slice magnetization relative to the thickness of the imaging slice.

Results

Both simulated SSFP signal intensities and effective slice broadening vary with flip angle and demonstrate a nonlinear dependence on inflow. Simulations with bloodlike T1 and T2 show that the effective slice thickness can be as large as 15 times the prescribed slice thickness. These effects can have significant clinical implications such as large frequency offset‐dependent signal enhancement, pulsatile flow artifacts, and spatial misrepresentation of blood signal that has already left the imaging slice.

Conclusion

Flow‐related signal changes in SSFP imaging exhibit highly complex parameter dependence, which predominantly has to be associated with frequency offset‐dependent outflow effects and a resulting broadening of the slice thickness. J. Magn. Reson. Imaging 2004;20:697–705. © 2004 Wiley‐Liss, Inc.
The influence of myocardial blood flow and volume of distribution on late Gd‐DTPA kinetics in ischemic heart failure
Authors: Klein Christoph , Nekolla Stephan G. , Balbach Thomas , Schnackenburg Bernhard , Nagel Eike , Fleck Eckart , Schwaiger Markus
Published: September 2004

Purpose

To determine the mechanism of enhancement of contrast‐enhanced MRI (ceMRI) in chronic ischemic myocardium. While ceMRI can identify scar tissue in chronic ischemic myocardium, the mechanism of enhancement is not completely understood.

Materials and Methods

A total of 11 patients with ischemic heart failure (ejection fraction [EF] 28 ± 9%) were imaged with ceMRI and positron emission tomography (PET) to measure myocardial blood flow (MBF). Longitudinal relaxation rate (T1) of blood, normal tissue, and scar tissue defined by ceMRI was determined before and two to 50 minutes after contrast (Look Locker technique), and the partition coefficient (λ) and volume of distribution (VD) were calculated.

Results

In scar and viable tissue, T1 was significantly different over the whole period after contrast, but not before contrast. However, T1 of scar and blood were similar five to 15 minutes post contrast, making the detection of subendocardial defects difficult. λ reached an initial steady state in viable tissue, but was delayed (20 minutes) in scar tissue. VD in scar was double that of viable tissue (0.54 ± 0.01 vs. 0.29 ± 0.02, respectively) indicating an increased interstitial space. Contrast wash‐in kinetics correlated moderately with MBF (r = –0.36), but well with the combination of MBF and VD (r = 0.59).

Conclusion

Late myocardial contrast kinetics depend on both MBF and VD; however the increased VD seems to be the main mechanism for the late enhancement effect. J. Magn. Reson. Imaging 2004;20:588–594. © 2004 Wiley‐Liss, Inc.
Comparison of dynamic gadolinium‐enhanced and ferumoxides‐enhanced MRI of the liver on high‐ and low‐field scanners
Authors: Limanond Piyaporn , Raman Steven S. , Sayre James , Lu David S.K.
Published: September 2004

Purpose

To compare the performance of dynamic gadolinium‐enhanced and ferumoxides‐enhanced MRI in the detection and characterization of hepatic lesions, on 1.5‐T and 0.2‐T magnets

Materials and Methods

In 41 patients (23 men, 18 women), 52 hepatic MR examinations were performed and retrospectively analyzed; 39 and 13 examinations were performed on 1.5‐T and 0.2‐T magnets, respectively. A total of 33 of 41 patients had known malignancies, and 31 of 33 patients had biopsy of at least one lesion. First, a combination of unenhanced T2‐weighted sequences and gradient‐echo T1‐weighted sequences were performed. Then, dynamic gadolinium‐enhanced (0.1 mmol/kg) T1 GRE sequences were obtained, followed by intravenous drip infusion of ferumoxides (10 μmol/kg). The T2‐weighted sequences were then repeated. The unenhanced and gadolinium‐enhanced images (the Gd set) were reviewed separately from the unenhanced and ferumoxides‐enhanced images (the ferumoxides set) by two abdominal imagers. The reviewers were blinded to clinical history and reviewed the individual studies in each set randomly. Each detected lesion was scored on a five‐point scale for characterization scores: nonsolid (1 or 2), indeterminate (3), or solid (4 or 5). A consensus review was then performed correlating all available pathology, imaging, clinical findings, and follow‐up to act as a gold standard. Receiver‐operating‐characteristic (ROC) curves were generated and both area‐under‐the‐curve (Az values) and sensitivity values were calculated. Significance of Az and sensitivity differences was assessed using standard Z‐test and chi‐square.

Results

Of 270 lesions detected by consensus, 211 were on 1.5‐T and 59 were on 0.2‐T scanners. The accuracy (Az values) of lesion detection overall, of both readers, was greater for the ferumoxides set than for the Gd set (reader 1: 0.95 vs. 0.89 (P < 0.05); reader 2: 0.91 vs. 0.78 (P < 0.05)). Az values for both readers were greater on the ferumoxides set for both the 1.5‐T scans and the 0.2‐T scans. Out of 270 lesions detected, 231 were characterized by consensus review as solid (185) or nonsolid (46). There was a significant improvement in lesion characterization for both readers on the GD set compared with the ferumoxides set on both high and low field scanners (Az reader 1: 0.99 vs. 0.96 (P < 0.05); Az reader 2: 0.99 vs. 0.95 (P < 0.05)), respectively.

Conclusion

At both 1.5‐T and 0.2‐T, ferumoxides‐enhanced sequences were better for lesion detection, while gadolinium‐enhanced sequences were better for lesion characterization, respectively. J. Magn. Reson. Imaging 2004;20:640–647. © 2004 Wiley‐Liss, Inc.
Dose optimization of mannitol solution for small bowel distension in MRI
Authors: Ajaj Waleed , Goehde Susanne C. , Schneemann Hubert , Ruehm Stefan G. , Debatin Jörg F. , Lauenstein Thomas C.
Published: September 2004

Purpose

To optimize the dose of a hydro solution containing 2.5% mannitol and 0.2% locust bean gum (LBG) for small bowel MRI in terms of bowel distension and patient acceptance.

Materials and Methods

A total of 10 healthy volunteers ingested a hydro solution containing 2.5% mannitol and 0.2% LBG. Four different volumes (1500, 1200, 1000, and 800 ml) were assessed on four different examination days. Small bowel distension was quantified on coronal two‐dimensional TrueFISP images by measuring the diameter of eight bowel loops throughout the jejunum and the ileum. In addition, volunteer acceptance was evaluated for every single examination by using a questionnaire.

Results

Optimal distension was obtained with either, 1000, 1200, or 1500 ml, with no statistically significant differences in distension between these groups. Administration of 800 ml led to significantly less distension of the small bowel. Significantly less side effects were noted using either 800 or 1000 ml compared to using larger volumes.

Conclusion

We recommend a dose of 1000 ml mannitol/LBG solution as an oral contrast agent for optimal bowel distension and minimal side effects. J. Magn. Reson. Imaging 2004;20:648–653. © 2004 Wiley‐Liss, Inc.
An accurate and robust method for unsupervised assessment of abdominal fat by MRI
Authors: Positano Vincenzo , Gastaldelli Amalia , Sironi Anna maria , Santarelli Maria Filomena , Lombardi Massimo , Landini Luigi
Published: September 2004

Purpose

To describe and evaluate an automatic and unsupervised method for assessing the quantity and distribution of abdominal adipose tissue by MRI.

Material and Methods

A total of 20 patients underwent whole‐abdomen MRI. A total of 32 transverse T1‐weighted images were acquired from each subject. The data collected were transferred to a dedicated workstation and analyzed by both our unsupervised method and a manual procedure. The proposed methodology allows the automatic processing of MRI axial images, segmenting the adipose tissue by fuzzy clustering approach. The use of an active contour algorithm on image masks provided by the fuzzy clustering algorithm allows the separation of subcutaneous fat from visceral fat. Finally, an automated procedure based on automatic image histogram analysis identifies the visceral fat.

Results

The accuracy, reproducibility, and speed of our automatic method were compared with the state‐of‐the‐art manual approach. The unsupervised analysis correlated well with the manual analysis, and was significantly faster than manual tracing. Moreover, the unsupervised method was not affected by intraobserver and interobserver variability.

Conclusion

The results obtained demonstrate that the proposed method can provide the volume of subcutaneous adipose tissue, visceral adipose tissue, global adipose tissue, and the ratio between subcutaneous and visceral fat in an unsupervised and effective manner. J. Magn. Reson. Imaging 2004;20:684–689. © 2004 Wiley‐Liss, Inc.
Diffusion tensor eigenvector directional color imaging patterns in the evaluation of cerebral white matter tracts altered by tumor
Authors: Field Aaron S. , Alexander Andrew L. , Wu Yu‐Chien , Hasan Khader M. , Witwer Brian , Badie Behnam
Published: September 2004

Purpose

To categorize the varied appearances of tumor‐altered white matter (WM) tracts on diffusion tensor eigenvector directional color maps.

Materials and Methods

Diffusion tensor imaging (DTI) was obtained preoperatively in 13 patients with brain tumors ranging from benign to high‐grade malignant, including primary and metastatic lesions, and maps of apparent diffusion coefficient (ADC), fractional anisotropy (FA), and major eigenvector direction were generated. Regions of interest (ROIs) were drawn within identifiable WM tracts affected by tumor, avoiding grossly cystic and necrotic regions, known fiber crossings, and gray matter. Patterns of WM tract alteration were categorized on the basis of qualitative analysis of directional color maps and correlation analysis of ADC and FA.

Results

Four basic patterns of WM alteration were identified: 1) normal or nearly normal FA and ADC, with abnormal tract location or tensor directions attributable to bulk mass displacement, 2) moderately decreased FA and increased ADC with normal tract locations and tensor directions, 3) moderately decreased FA and increased ADC with abnormal tensor directions, and 4) near isotropy. FA and ADC were inversely correlated for Patterns 1–3 but did not discriminate edema from infiltrating tumor. However, in the absence of mass displacement, infiltrating tumor was found to produce tensor directional changes that were not observed with vasogenic edema, suggesting the possibility of discrimination on the basis of directional statistics.

Conclusion

Tumor alteration of WM tracts tends to produce one of four patterns on FA and directional color maps. Clinical application of these patterns must await further study. J. Magn. Reson. Imaging 2004;20:555–562. © 2004 Wiley‐Liss, Inc.
In vivo 4.0‐T magnetic resonance investigation of spinal cord inflammation, demyelination, and axonal damage in chronic‐progressive experimental allergic encephalomyelitis
Authors: Cook Lisa L. , Foster Paula J. , Mitchell J. Ross , Karlik Stephen J.
Published: September 2004

Purpose

To image and dissect the lumbar spinal cord of guinea pigs with chronic‐progressive experimental allergic encephalomyelitis (CP‐EAE) and directly correlate the pathology to the magnetic resonance (MR) image data obtained at 4 T and determine if these MR contrasts can accurately differentiate a specific type of pathology from control tissue.

Materials and Methods

The amount of inflammation, demyelination, and axonal pathology were quantified in the whole cord cross sections. The signal intensities (SIs) for 228 individual regions of interest (ROIs) (normal‐appearing white matter (NAWM) and tissue containing inflammation with or without demyelination) were measured directly from the corresponding area on the MR images.

Results

Conventional MR contrast SIs and magnetization transfer ratio (MTR) were related to the degree of demyelination and presence of inflammation. MTR and proton density‐weighted (PDw) SIs were both moderately related to axonal density. The SIs for NAWM and in lesions containing both cellular infiltrates and demyelination in all conventional MR contrast images were also increased, whereas the MTR was decreased when compared to control tissue.

Conclusion

The SIs from the conventional MR contrasts and MTR at 4 T were sensitive to the presence of disease within CP‐EAE spinal cord, but were not specific to the underlying pathology. J. Magn. Reson. Imaging 2004;20:563–571. © 2004 Wiley‐Liss, Inc.
Delayed hyper‐enhancement of myocardium in hypertrophic cardiomyopathy with asymmetrical septal hypertrophy: Comparison with global and regional cardiac MR imaging appearances
Authors: Amano Yasuo , Takayama Morimasa , Takahama Katsuya , Kumazaki Tatuso
Published: September 2004

Purpose

To evaluate the relationship between delayed hyper‐enhancement of the myocardium and global and regional cardiac abnormalities in hypertrophic cardiomyopathy (HCM) with asymmetrical septal hypertrophy using magnetic resonance (MR) imaging.

Materials and Methods

Twenty‐three patients with HCM with asymmetrical septal hypertrophy were examined using a 1.5‐T MR unit. Contrast‐enhanced inversion‐recovery gradient‐echo imaging was performed to observe the myocardial damages associated with HCM. Balanced steady‐state free precession imaging was performed to assess regional wall abnormalities and ejection fraction, and black‐blood fast spin‐echo imaging was performed to assess left atrial diameter.

Results

Delayed hyper‐enhancement of the myocardium was primarily observed in the interventricular septal wall. Septal walls with the higher transmural extent of delayed hyper‐enhancement were significantly thicker at end‐diastole and end‐systole (P < 0.05), and tended to show a decreased percentage systolic wall thickening (P = 0.079). There were no differences in theses values between non‐enhancing septal walls and septal walls with the transmural extent < 50%.

Conclusion

The high transmural extent of delayed hyper‐enhancement of the myocardium may reflect the severe myocardial damage associated with the regional hypertrophy and hypokinesia in HCM. J. Magn. Reson. Imaging 2004;20:595–600. © 2004 Wiley‐Liss, Inc.
Long‐term imaging effects in rat liver after a single injection of an iron oxide nanoparticle based MR contrast agent
Authors: Briley‐Sæbø Karen , Hustvedt Svein‐Olaf , Haldorsen Anita , Bjørnerud Atle
Published: September 2004

Purpose

To investigate the duration of liver R2* enhancement and pharmacokinetics following administration of an iron oxide nanoparticle in a rat model.

Materials and Methods

Rats were injected with 0, 1, 2, or 5 mg Fe/kg of NC100150 Injection, and quantitative in vivo 1/T2* liver measurements were obtained between 1 and 133 days after injection. The concentration of NC100150 Injection was determined by relaxometry methods in ex vivo rat liver homogenate.

Results

At all dose levels, 1/T2* remained greater than control values up to 63 days after injection. In the highest dose group, 1/T2* was above control levels during the entire 133 day time‐course investigated. There were no quantifiable amounts of NC100150 Injection present 63 days after injection in any of the dose groups. The half‐life of NC100150 Injection in rat liver was dose dependent. For the lowest dose group, the degradation of the particles could be defined by a mono‐exponential function with a half‐life of eight days. For the 2 and 5 mg Fe/kg dose groups, the degradation was bi‐exponential with a fast initial decay of seven to eight days followed by a slow terminal decay of 43–46 days.

Conclusion

NC100150 Injection exhibits prolonged 1/T2* enhancement in rat liver. The liver enhancement persisted at time points when the concentration of iron oxide particles present in the liver was below method detection limits. The prolonged 1/T2* enhancement is likely a result of the particle breakdown products and the induction of ferritin and hemosiderin with increasing iron cores/loading factors. J. Magn. Reson. Imaging 2004;20:622–631. © 2004 Wiley‐Liss, Inc.
Efficacy of 904 nm gallium arsenide low level laser therapy in the management of chronic myofascial pain in the neck: A double‐blind and randomize‐controlled trial
Authors: Gur Ali , Sarac Aysegul Jale , Cevik Remzi , Altindag Ozlem , Sarac Serdar
Published: September 2004

Background and Objectives

A prospective, double‐blind, randomized, and controlled trial was conducted in patients with chronic myofascial pain syndrome (MPS) in the neck to evaluate the effects of infrared low level 904 nm Gallium‐Arsenide (Ga‐As) laser therapy (LLLT) on clinical and quality of life (QoL).

Study Design/Patients and Methods

The study group consisted of 60 MPS patients. Patients were randomly assigned to two treatment groups: Group I (actual laser; 30 patients) and Group II (placebo laser; 30 patients). LLLT continued daily for 2 weeks except weekends. Follow‐up measures were evaluated at baseline, 2, 3, and 12 weeks. All patients were evaluated with respect to pain at rest, pain at movement, number of trigger points (TP), the Neck Pain and Disability Visual Analog Scale (NPAD), Beck depression Inventory (BDI), and the Nottingham Health Profile (NHP).

Results

In active laser group, statistically significant improvements were detected in all outcome measures compared with baseline (P < 0.01) while in the placebo laser group, significant improvements were detected in only pain score at rest at the 1 week later of the end of treatment. The score for self‐assessed improvement of pain was significantly different between the active and placebo laser groups (63 vs. 19%) (P < 0.01).

Conclusion

This study revealed that short‐period application of LLLT is effective in pain relief and in the improvement of functional ability and QoL in patients with MPS. Lasers Surg. Med. 35:229–235, 2004. © 2004 Wiley‐Liss, Inc.
Laser and novel light source treatments for psoriasis
Authors: Tournas Joshua A. , Lowe Nicholas J. , Yamauchi Paul S.
Published: September 2004

Background and Objectives

There are many treatment modalities for psoriasis including topical therapy, ultraviolet light therapy, systemic agents, and more recently the advent of the biologic agents.

Study Design/Materials and Methods

In addition, selective treatment using lasers and light sources that target the individual psoriatic plaques have also been employed.

Results/Conclusion

This article will highlight and review the employment of laser‐assisted devices in the treatment of plaque psoriasis. Lasers Surg. Med. 35:165–173, 2004. © 2004 Wiley‐Liss, Inc.
Comparison of red and green laser doppler imaging of blood flow
Authors: Murray Andrea K. , Gorodkin Rachel E. , Moore Tonia L. , Gush Rodney J. , Herrick Ariane L. , King Terence A.
Published: September 2004

Background and Objectives

Laser Doppler imaging (LDI) of perfusion has been performed with a novel green wavelength (532 nm) for comparison with a HeNe laser (633 nm), the aim being validation of the green laser wavelength as a research tool.

Study Design/Materials and Methods

The effect of wavelength and power on images was investigated and perfusion response following both finger occlusion and local heating of the dorsum were examined as reproducible stimuli for clinical studies.

Results

The most striking difference between red and green LDI is the absence of veins on green LDI, which are seen with red LDI. Differences have been quantified using vein LDI profiles. Differences were found between blood flow responses imaged by red and green LDI (3 and 5 mW, respectively) for occlusion and heat stimuli. Results are discussed in the context of light penetration.

Conclusions

Red and green wavelengths appear to image different components of the microcirculation. Lasers Surg. Med. 35:191–200, 2004. © 2004 Wiley‐Liss, Inc.
Neurotransmitter release changes induced by low power 830 nm diode laser irradiation on the neuromuscular junctions of the mouse
Authors: Nicolau Renata Amadei , Martinez Manel Santafé , Rigau Josepa , Tomàs Josep
Published: September 2004

Background and Objective

Treating patients with a Gallium‐Aluminum‐Arsenide (GaAlAs) infrared (IR) diode laser reduces muscle spasm and increases mobility in the muscles. The effect of low intensity laser irradiation on nerve function, growth, and repair mechanisms is a contentious area of research. We have addressed one aspect of this controversy by systematically examining the influence of 830 nm laser radiation on neurotransmitter release in neuromuscular junctions (NMJ) of the mouse diaphragm.

Study Design/Materials and Methods

Thirty adult mice were studied. Diode laser GaAlAs 830 nm (4 and 12 J/cm2) was used. Neurotransmitter release was studied by conventional intracellular recording techniques on curarized muscles or high magnesium media. The quantal content, amplitude, and latency of the end‐plate potentials (EPPs) were analyzed. Frequency and amplitude were evaluated for the miniature end‐plate potentials (MEPPs). Facilitation of the neurotransmitter release was also evaluated by paired pulse stimulation.

Results and Conclusions

The irradiated (12 J/cm2) muscles showed a significant reduction in quantal content (P = 0.01) and EPP amplitude (P = 0.04), but the latency, spontaneous transmitter release (MEPPs) and paired pulse facilitation did not change. No alterations were observed in NMJ irradiated with 4 J/cm2. We conclude that 830 nm diode laser irradiation (at a dose of 12 J/cm2) can affect the evoked neurotransmitter release in the mouse motor endplates. Lasers Surg. Med. 35:236–241, 2004. © 2004 Wiley‐Liss, Inc.