bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectrophotometric determination of isopropamide Iodide and trifluoperazine hydrochloride in presence of trifluoperazine oxidative degradate
Authors: Abbas Samah S. , Zaazaa Hala E. , Abdelkawy M. , Abdelrahman Maha M.
Published: February 2010

Four sensitive, selective and precise stability indicating methods for the determination of isopropamide iodide (ISO) and trifluoperazine hydrochloride (TPZ) in their binary mixture and in presence of trifluoperazine oxidative degradate (OXD). Method A is a derivative spectrophotometric one, where ISO was determined by first derivative (D1) at 226.4 nm while TPZ was determined by second derivative (D2) at 270.2 nm. Method B is the first derivative of the ratio spectra (DD1) spectrophotometric method, ISO can be determined by measuring the peak amplitude at 227.4 nm using 5 µg mL−1of OXD as a divisor, while TPZ can be determined by measuring the peak amplitude at 249.2 and 261.4 nm using 15 µg mL−1of ISO as a divisor. Method C is the isoabsorptive spectrophotometric method. This method allows determination of ISO and TPZ in their binary mixture by measuring total concentration of ISO and TPZ at their isoabsorptive point at λ229.8nm (Aiso1) while TPZ concentration alone can be determined at λmax311.2 nm, then ISO concentration can be determined by subtraction. On the same basis TPZ can be determined in presence of ISO and OXD, where OXD concentration alone was determined by measuring the peak amplitude at λ281.6and λ309.4nm while total concentration of TPZ and OXD was determined at their isoabsorptive points at (Aiso2= 270.2 nm), (Aiso3= 310.6 nm) and (Aiso4= 331.8 nm) then TPZ concentration was determined by subtraction. Method D is the multivariate calibration techniques [the classical least squares (CLS), principal component regression (PCR) and partial least squares (PLS)], using the information contained in the absorption spectra of ISO, TPZ and OXD mixtures. The selectivity of the proposed methods was checked using laboratory prepared mixtures. The proposed methods have been successfully applied to the analysis of ISO and TPZ in pharmaceutical dosage form without interference from other dosage form additives and the results were statistically compared with the reported method. Copyright © 2010 John Wiley & Sons, Ltd.
Identification of the growth‐hormone‐releasing peptide‐2 (GHRP‐2) in a nutritional supplement
Authors: Thomas Andreas , Kohler Maxie , Mester Joachim , Geyer Hans , Schänzer Wilhelm , Petrou Michael , Thevis Mario
Published: February 2010

Black market products of a pharmaceutical nature and nutritional supplements have received substantial and increasing attention because of potential performance enhancement in elite and non‐professional sports. In addition, improved general health is claimed for non‐competing individuals. The risks and foreseeable dangers of the uncontrolled use of highly potent and non‐approved pharmaceutical compounds in healthy individuals are of considerable concern. In the present case report, the emerging drug candidate GHRP‐2 with verified growth‐hormone‐releasing properties was identified and quantified in tablets offered as an over‐the‐counter nutritional supplement. The impact of this orally active peptide on the hGH/IGF‐axis has been established for several years and its illicit use in elite sports has been assumed. As a releasing factor for hGH, GHRP‐2 belongs to the list of substances prohibited by the World Anti‐Doping Agency (WADA). Unfortunately, to date there is no routinely performed assay for the determination of these peptides potentially occurring in biological fluids of competing athletes, but the present data will facilitate the implementation by providing principle analytical information on liquid chromatographic and mass spectrometric behaviour. Qualitative identification of the target analyte after extraction from the tablet matrix was performed by high resolution/high accuracy mass spectrometry after liquid chromatographic separation under consideration of the accurate masses and the ratios of the protonated molecules and their fragment ions derived from their collisionally induced dissociation. Quantitative results were obtained by means of liquid chromatography coupled to a triple quadrupole mass spectrometer and linear regression using an external calibration curve (with GHRP‐2 reference compound) adjusted via internal standard (Hexarelin). Hereby, the content of GHRP‐2 was determined with approximately 50 µg per tablet. Copyright © 2010 John Wiley & Sons, Ltd.
Modeling the electrophoretic behavior of quinolones in aqueous and hydroorganic media
Authors: Benavente Fernando , Giménez Estela , Barrón Dolores , Barbosa José , Sanz‐Nebot Victoria
Published: February 2010

The applicability of the classical semiempirical relationships between the electrophoretic mobility and charge‐to‐mass ratio (me versus q/Mα) has been investigated to describe migration behavior of a series of quinolones in aqueous and hydroorganic media. The Stoke's law (α=1/3), the classical polymer model (α=1/2) and the Offord's surface law (α=2/3) were evaluated in the pH range comprised between 2 and 11 in ACN–water mixtures of 0, 10 and 30% m/m ACN. As accurate acidity constant values were available for charge calculations, correlations were excellent. The results obtained using the Offord's surface law were slightly better and the plots of q/M2/3 against the separation electrolyte pH were used to select the optimum pH values for separation of a quinolone mixture. The electropherograms simulated considering the accurate charge‐to‐mass ratio of each quinolone at the selected pH values were in good agreement with the experimental results. The ability of these relationships to predict the separation of the studied quinolones at a certain pH value in methanol–water and THF–water mixtures was also demonstrated.
Electrophoretic collision of a DNA molecule with a small elliptical obstacle
Authors: Cho Jaeseol , Kumar Satish , Dorfman Kevin D.
Published: February 2010

We present a Brownian dynamics study of the collision and unhooking of a λ‐DNA molecule with an elliptical obstacle. The semi‐major and semi‐minor axes of the obstacle are comparable to the radius of gyration of the DNA, and the field is sufficiently strong to cause frequent hairpin formation upon collision. We focus on how the dynamics of a head‐on collision (impact parameter of zero) are affected by the angle between the major axis of the ellipse and the direction of the electric field far from the elliptical surface. When this orientation angle breaks the symmetry of the system, we find that the collision dynamics are considerably more complicated than the cylindrical obstacle case. In particular, a higher strain rate at the stagnation point on an elliptical surface does not always lead to a higher hooking probability. As a result, elliptical obstacles should be less effective than cylindrical obstacles for DNA separations based on hairpin formation.
Ionic strength effects on electrophoretic focusing and separations
Authors: Bahga Supreet S. , Bercovici Moran , Santiago Juan G.
Published: February 2010

We present a numerical and experimental study of the effects of ionic strength on electrophoretic focusing and separations. We review the development of ionic strength models for electrophoretic mobility and chemical activity and highlight their differences in the context of electrophoretic separation and focusing simulations. We couple a fast numerical solver for electrophoretic transport with the Onsager–Fuoss model for actual ionic mobility and the extended Debye–Huckle theory for correction of ionic activity. Model predictions for fluorescein mobility as a function of ionic strength and pH compare well with data from CZE experiments. Simulation predictions of preconcentration factors in peak mode ITP also compare well with the published experimental data. We performed ITP experiments to study the effect of ionic strength on the simultaneous focusing and separation. Our comparisons of the latter data with simulation results at 10 and 250 mM ionic strength show the model is able to capture the observed qualitative differences in ITP analyte zone shape and order. Finally, we present simulations of CZE experiments where changes in the ionic strength result in significant change in selectivity and order of analyte peaks. Our simulations of ionic strength effects in capillary electrophoresis compare well with the published experimental data.
Electric field‐enhanced transport across phase boundaries and membranes and its potential use in sample pretreatment for bioanalysis
Authors: Kubáň Pavel , Šlampová Andrea , Boček Petr
Published: February 2010

Separation techniques, such as electrodialysis, electroextraction, electro‐membrane extraction and extraction across phase interfaces, are reviewed and discussed as methods for sample cleanup and preconcentration. This survey clearly shows that electromigration of ionic species across phase interfaces, especially across supported liquid membranes, may be very selective and is strongly dependent on the chemical composition of these interfaces. Thus, electric field‐enhanced transport across chemically tailored liquid membranes may open new perspectives in preparative analytical chemistry. This review offers comprehensive survey of related literature and discussion of the topic, which may stimulate interest of experts and practitioners in bioanalysis.
Nonlinear Smoluchowski velocity for electroosmosis of Power‐law fluids over a surface with arbitrary zeta potentials
Authors: Zhao Cunlu , Yang Chun
Published: February 2010

Electroosmotic flow of Power‐law fluids over a surface with arbitrary zeta potentials is analyzed. The governing equations including the nonlinear Poisson–Boltzmann equation, the Cauchy momentum equation and the continuity equation are solved to seek exact solutions for the electroosmotic velocity, shear stress, and dynamic viscosity distributions inside the electric double layer. Specifically, an expression for the general Smoluchowski velocity is obtained for electroosmosis of Power‐law fluids in a fashion similar to the classic Smoluchowski velocity for Newtonian fluids. The existing Smoluchowski slip velocities under two special cases, (i) for Newtonian fluids with arbitrary zeta potentials and (ii) for Power‐law fluids with small zeta potentials, can be recovered from our derived formula. It is interesting to note that the general Smoluchowski velocity for non‐Newtonian Power‐law fluids is a nonlinear function of the electric field strength and surface zeta potentials; this is due to the coupling electrostatics and non‐Newtonian fluid behavior, which is different from its counterpart for Newtonian fluids. This general Smoluchowski velocity is of practical significance in determining the flow rates in microfluidic devices involving non‐Newtonian Power‐law fluids.
Advances in the theory and application of MEEKC
Authors: Ryan Richie , Donegan Sheila , Power Joe , Altria Kevin
Published: February 2010

MEEKC is an electrodriven separation technique, which utilises the unique properties of a microemulsion (ME) as a background electrolyte to achieve separation of a diverse range of solutes. MEs are composed of nanometre‐sized oil droplets suspended in aqueous buffer, which is commonly referred to as an oil‐in‐water ME. The droplets are stabilised by the presence of a surfactant and co‐surfactant. The use of water‐in‐oil MEs in MEEKC has also been investigated. This review details the advances in MEEKC‐based separations from the period 2008 to 2009. Areas covered include online sample concentration, suppressed electroosmosis MEEKC, chiral separation, MEEKC‐MS, and structure–migration relationships. The review also includes a fundamental introduction to MEEKC, along with the presentation of recent applications.
Destabilization of Pickering emulsions using external electric fields
Authors: Hwang Kyuho , Singh Pushpendra , Aubry Nadine
Published: February 2010

It is known that emulsions can be stabilized by the presence of particles that get trapped at fluid–fluid interfaces and prevent adjacent drops from coalescing with one another. We show here that such emulsions, or Pickering emulsions, can be destabilized by applying external electric fields. This is demonstrated experimentally by studying water drops in decane and silicone oil drops in corn oil in the presence of micro‐sized particles. It is shown that the primary phenomenon responsible for the destabilization is the motion of particles on the surface of drops in the presence of a uniform electric field. Although there should be no electrostatic forces acting on neutral particles in a uniform electric field, the presence of the drop itself introduces nonuniformity, which leads to dielectrophoretic forces acting on the particles and is thus responsible for particle motions along the drop surface. Particles translate to either the poles or the equator of the drop, depending on the relative dielectric constants of the particles, the surrounding fluid and the fluid within the drop. Such motions break the particle barrier, thus allowing for drops to merge with one another and therefore destabilizing the emulsion.
The dependence of the electrophoretic mobility of small organic ions on ionic strength and complex formation
Authors: Allison Stuart A. , Pei Hongxia , Baek Saerom , Brown Jocelyn , Lee Min Y. , Nguyen Vu , Twahir Umar T. , Wu Hengfu
Published: February 2010

The ionic strength dependence of the electrophoretic mobility of small organic anions with valencies up to −3 is investigated in this study. Provided the anions are not too aspherical, it is argued that shape and charge distribution have little influence on mobility. To a good approximation, the electrophoretic mobility of a small particle should be equal to that of a model sphere with the same hydrodynamic radius and same net charge. For small ions, the relaxation effect (distortion of the ion atmosphere from equilibrium due to external electric and flow fields) is significant even for monovalent ions. Alternative procedures of accounting for the relaxation effect are examined. In order to account for the ionic strength dependence of a specific set of nonaromatic and aromatic anions in aqueous solution, it is necessary to include complex formation between the anion with species in the BGE. A number of possible complexes are considered. When the BGE is Tris‐acetate, the most important of these involves the complex formed between anion and Tris, the principle cation in the BGE. When the BGE is sodium borate, an anion–anion (borate) complex appears to be important, at least when the organic anion is monovalent. An algorithm is developed to analyze the ionic strength dependence of the electrophoretic mobility. This algorithm is applied to two sets of organic anions from two independent research groups.
Analysis of fullerene-C60 and kinetic measurements for its accumulation and depuration in Daphnia magna
Authors: Tervonen Kukka , Waissi Greta , Petersen Elijah J. , Akkanen Jarkko , Kukkonen Jussi V.K.
Published: February 2010

A simple method for analyzing masses of water suspended fullerenes (nC60) in Daphnia magna by extracting to toluene and measuring by ultraviolet-vis spectrophotometry was developed. This method was used to assess bioaccumulation and depuration rates by daphnia after nC60 exposure in artificial freshwater. Accumulation was rapid during the first few hours, and based on accumulation modeling, 90% of the steady-state concentration was reached in 21 h. After exposure for 24 h to a 2 mg/L fullerene solution, the daphnia accumulated 4.5 ± 0.7 g/kg wet weight, or 0.45% of the organism wet mass. Daphnids exposed to 2 mg/L fullerenes for 24 h eliminated 46 and 74% of the accumulated fullerenes after depuration in clean water for 24 and 48 h, respectively. Transmission electron microscopy revealed that the majority of the fullerenes present in the gut of daphnids were large agglomerates. The significant fullerene uptake and relatively slow depuration suggest that D. magna may play a role as a carrier of fullerene from one trophic level to another. Additionally, D. magna may impact the fate of suspended fullerene particles in aquatic ecosystems by their ability to pack fullerene agglomerates into larger particles than were found in the exposure water, and then excrete agglomerates that are not stable in water, causing them to settle out of solution. This process decreases fullerene exposure to other aquatic organisms in the water column but may increase exposure to benthic organisms in the sediment. Environ. Toxicol. Chem. 2010;29:1072–1078. © 2010 SETAC
Second salvage surgery for re‐recurrent oral cavity and oropharynx carcinoma
Authors: Agra Ivan Marcelo Gonçalves , Filho João Gonçalves , Martins Everton Pontes , Kowalski Luiz Paulo
Published: February 2010

Background.

Salvage surgery is considered the best treatment approach for patients with recurrent oral carcinoma. Unfortunately, 50% to 60% of the patients who undergo salvage surgery will develop further locoregional recurrence, and they are not usually considered for further treatment. Our aim in this study was to report our experience with a second salvage surgery for selected patients with re‐recurrent oral cavity and oropharyngeal squamous cell carcinoma (SCC).

Methods.

Forty‐one patients underwent a second salvage surgical procedure, with curative intention for re‐recurrent oral cancer. The surgical treatment used was wide local resection in 34 cases, neck dissection in 9 cases, and isolated neck dissection in 7 cases.

Results.

Cancer‐specific survival (CSS) rate in 3 years was at 20%. Patients with re‐recurrence in <6 months presented 3‐year CSS null, whereas patients with re‐recurrence after 6 months presented 3‐year CSS of 32.3% (p = .007).

Conclusion.

Second salvage surgery can be considered a potentially curative therapeutic approach for a selected group of patients with re‐recurrent oral SCC. The disease‐free interval was the main clinical factor associated with the prognosis. © 2010 Wiley Periodicals, Inc. Head Neck, 2010
Better understanding tumor–host interaction in head and neck cancer to improve the design and development of immunotherapeutic strategies
Authors: Badoual Cécile , Sandoval Federico , Pere Helene , Hans Stephane , Gey Alain , Merillon Nathalie , Van Ryswick Cordelia , Quintin‐Colonna Françoise , Bruneval Patrick , Brasnu Daniel , Fridman Wolf H. , Tartour Eric
Published: February 2010

Head and neck cancers are heavily infiltrated by immune cells, the significance of which is complex. The natural immune response against head and neck tumors, including anti‐human papillomavirus (HPV) T cells, and humoral responses has been clearly documented. However, during the course of tumor progression, co‐option of the immune system by tumor cells for their own advantage and increased resistance of tumor cells to immune attack also occur. Inflammation and immune subversion to support angiogenesis are key factors promoting tumor growth. Only a better understanding of this tumor–host interaction will permit a rational design of new immunotherapeutic approaches combining immunostimulation with drugs endowed with the ability to counteract immunoevasion mechanisms. © 2010 Wiley Periodicals, Inc. Head Neck, 2010
Future of the TNM classification and staging system in head and neck cancer
Authors: Takes Robert P. , Rinaldo Alessandra , Silver Carl E. , Piccirillo Jay F. , Haigentz Missak , Suárez Carlos , Van der Poorten Vincent , Hermans Robert , Rodrigo Juan Pablo , Devaney Kenneth O. , Ferlito Alfio
Published: February 2010

Staging systems for cancer, including the most universally used TNM classification system, have been based almost exclusively on anatomic information. However, the question arises whether staging systems should be based on this information alone. Other parameters have been identified that should be considered for inclusion in classification systems like the TNM. This is all the more important, as a shift toward nonsurgical treatments for head and neck cancer has been made over the years. For these treatment modalities tumor/biologic characteristics next to anatomic information may be particularly important for treatment choice and outcome. The shortcomings of the current TNM classification system will be discussed, along with suggestions for improvement and expansion of the TNM system based on tumor, patient, and environment‐related factors. Further improvement of the TNM classification is expected to result in better treatment choices, outcome and prognostication of patients with head and neck cancer. © 2010 Wiley Periodicals, Inc. Head Neck, 2010
Sonographic diagnosis of a large and deep endometrioma of the uterine cervix
Authors: Coccia Maria Elisabetta , Rizzello Francesca , Castellacci Eleonora , Cammilli Fiamma
Published: February 2010

We present a rare case of endometriosis of the cervix. Transvaginal sonography showed a 35‐mm cyst in the cervix with diffuse, low‐level internal echoes. Transvaginal sonography‐guided aspiration with a 17‐gauge needle was performed, yielding a very thick chocolate‐colored fluid. Cytological examination of the fluid revealed the presence of endometrial cells. Symptoms resolved after aspiration and no recurrence has developed. © 2010 Wiley Periodicals, Inc. J Clin Ultrasound, 2010
Prenatal diagnosis of an intertwin membrane hematoma
Authors: Kacerovsky Marian , Tosner Jindrich
Published: February 2010

We report a case of a 26‐year‐old woman, gravida 2, para 1, with a dichorionic diamniotic twin pregnancy at 33 weeks of gestation with a 1‐day history of mild vaginal bleeding and irregular uterine activity. Ultrasonography showed 18 × 15 × 3‐cm‐sized complex hypoechoic mass located in the dividing intertwin membrane. Based on this finding, the diagnosis of an intertwin membrane hematoma was made. This unusual sonographic diagnosis was confirmed during the cesarean section. In the case of dichorionic twin pregnancy, partial placental abruption can lead to a subclinical intertwin membrane hematoma. © 2010 Wiley Periodicals, Inc. J Clin Ultrasound 38:397‐399, 2010
Cardiac MRI evaluation of nonischemic cardiomyopathies
Authors: François Christopher J. , Schiebler Mark L. , Reeder Scott B.
Published: February 2010

The purpose of this manuscript is to review the major MRI findings in patients with nonischemic cardiomyopathies. Cardiac MRI has become an integral part in the diagnosis and management of patients with nonischemic cardiomyopathies. Findings on cardiac MRI studies can help distinguish between different types of cardiomyopathies and can provide valuable diagnostic and prognostic information. J. Magn. Reson. Imaging 2010;31:518–530. © 2010 Wiley‐Liss, Inc.
Preinterventional quantitative magnetic resonance imaging predicts uterus and leiomyoma size reduction after uterine artery embolization
Authors: Sipola Petri , Ruuskanen Anu , Yawu Liu , Husso Minna , Vanninen Ritva , Hippeläinen Maritta , Manninen Hannu
Published: February 2010

Purpose:

To investigate the relationship between magnetic resonance imaging (MRI) measures and uterus and leiomyoma size reductions after uterine artery embolization (UAE).

Materials and Methods:

Fifty‐two women with leiomyomas underwent selective UAEs. Uterine and dominant leiomyoma sizes were measured with preinterventional MRI and a 6‐month follow‐up MRI. Four MRI measures of the dominant leiomyoma were recorded: T1 time; T2 time; leiomyoma‐to‐skeletal muscle T2 SI‐ratio; and percentage of contrast enhancement. To evaluate the predictive value of MRI measures we used Spearman rank correlation, area under the receiver operating characteristic (ROC) curve (Az), and values for diagnostic performance.

Results:

Uterus and dominant leiomyoma size reductions were highly variable. Leiomyoma size reductions of ≥75% were accurately predicted with leiomyoma‐to‐skeletal muscle T2 SI‐ratio (ROC curve Az = 0.930; 95% confidence interval [CI]: 0.853, 1.000). Leiomyoma size reductions ≥75% were predicted by leiomyoma‐to‐skeletal muscle T2 SI‐ratio ≥3.5 and T1‐time ≥750 msec with 100% and 86% sensitivities and 67% and 72% specificities, respectively. Uterus size reduction ≥50% were identified by dominant leiomyoma‐to‐skeletal muscle T2 SI‐ratio ≥2.5.

Conclusion:

Uterus and dominant leiomyoma size reductions after UAE were predicted with preoperative MRI measures of the dominant leiomyoma. J. Magn. Reson. Imaging 2010;31:617–624. © 2010 Wiley‐Liss, Inc.
Accelerating non‐contrast‐enhanced MR angiography with inflow inversion recovery imaging by skipped phase encoding and edge deghosting (SPEED)
Authors: Chang Zheng , Xiang Qing‐San , Shen Hao , Yin Fang‐Fang
Published: February 2010

Purpose:

To accelerate non‐contrast‐enhanced MR angiography (MRA) with inflow inversion recovery (IFIR) with a fast imaging method, Skipped Phase Encoding and Edge Deghosting (SPEED).

Materials and Methods:

IFIR imaging uses a preparatory inversion pulse to reduce signals from static tissue, while leaving inflow arterial blood unaffected, resulting in sparse arterial vasculature on modest tissue background. By taking advantage of vascular sparsity, SPEED can be simplified with a single‐layer model to achieve higher efficiency in both scan time reduction and image reconstruction. SPEED can also make use of information available in multiple coils for further acceleration. The techniques are demonstrated with a three‐dimensional renal non‐contrast‐enhanced IFIR MRA study.

Results:

Images are reconstructed by SPEED based on a single‐layer model to achieve an undersampling factor of up to 2.5 using one skipped phase encoding direction. By making use of information available in multiple coils, SPEED can achieve an undersampling factor of up to 8.3 with four receiver coils. The reconstructed images generally have comparable quality as that of the reference images reconstructed from full k‐space data.

Conclusion:

As demonstrated with a three‐dimensional renal IFIR scan, SPEED based on a single‐layer model is able to reduce scan time further and achieve higher computational efficiency than the original SPEED. J. Magn. Reson. Imaging 2010;31:757–765. © 2010 Wiley‐Liss, Inc.
Apparent diffusion coefficient and fractional anisotropy in the vertebral bone marrow
Authors: Ueda Yu , Miyati Tosiaki , Ohno Naoki , Motono Yuko , Hara Masaki , Shibamoto Yuta , Kasai Harumasa , Kawamitsu Hideaki , Matsubara Kosuke
Published: February 2010

Purpose:

To assess the state of cancellous tissue we analyzed the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in vertebral bone marrow.

Materials and Methods:

With 1.5 T magnetic resonance imaging (MRI), single‐shot diffusion echo planar imaging was used with b factors of 0 and 1000 s/mm2, diffusion‐sensitizing gradient in six directions, sensitivity encoding technique, effective TE of 74 msec, and TR of 1800 msec. ADC and FA were determined in the lumbar vertebral body of 11 normal subjects (age 31 632–635 years), and then compared with the bone mineral density (BMD) obtained with dual‐energy x‐ray absorptiometry (DXA). Moreover, fat fraction (FF) of the bone marrow was measured with spectral presaturation with inversion recovery (SPIR) in the same subject.

Results:

A strong negative correlation was found between ADC and BMD for low or moderate FF in vertebral bone marrow. Moreover, a significant positive correlation was noted between ADC and FF in this region. There was a positive correlation between FA and BMD, and no correlation between FA and FF in the vertebral bone marrow.

Conclusion:

Diffusion analyses with ADC and FA make it possible to obtain more detailed information on the structure of cancellous tissue and bone metabolism. J. Magn. Reson. Imaging 2010;31:632–635. © 2010 Wiley‐Liss, Inc.
Detection of hepatic hypovascular metastases: 3D gradient echo MRI using a hepatobiliary contrast agent
Authors: Choi Jin‐Young , Choi Jin‐Sub , Kim Myeong‐Jin , Lim Joon Seok , Park Mi Suk , Kim Joo Hee , Chung Yong Eun
Published: February 2010

Purpose:

To assess the diagnostic performance of gadobenate dimeglumine‐enhanced 3D gradient echo (3D‐GRE) magnetic resonance imaging (MRI) for the detection of hepatic hypovascular metastases.

Materials and Methods:

We retrospectively analyzed the initial radiologic reports of MRI of 41 patients with suspected hepatic metastases. Seventy‐nine metastatic lesions were confirmed by histopathology or intraoperative ultrasound (IOUS). The sensitivity and positive predictive values for the diagnosis of hepatic metastasis were determined among each MRI set (hepatobiliary phase, precontrast images, dynamic imaging). The diagnostic performance of dynamic image set and combined dynamic and hepatobiliary image set was also evaluated by two radiologists using alternative free response receiver operating characteristic (ROC) analysis.

Results:

The overall detection rate and positive predictive value of MR were 96.2% (76/79) and 96.2% (76/79), respectively. Images obtained with hepatobiliary phase 3D‐GRE showed a significantly better detection rate compared to those with precontrast sequences or dynamic imaging (P = 0.008 and 0.016, respectively). Regarding lesions 1 cm or smaller, the detection rate was 90.3% (28/31). Each reader showed a higher Az value of the combined hepatobiliary image set than those of the dynamic image set.

Conclusion:

3D‐GRE MRI using a hepatobiliary contrast agent is an accurate tool in the detection of hepatic hypovascular metastases and improves detection rate compared with precontrast and dynamic imaging. J. Magn. Reson. Imaging 2010;31:571–578. © 2010 Wiley‐Liss, Inc.
Diagnosis of cirrhosis with intravoxel incoherent motion diffusion MRI and dynamic contrast‐enhanced MRI alone and in combination: Preliminary experience
Authors: Patel Jignesh , Sigmund Eric E. , Rusinek Henry , Oei Marcel , Babb James S. , Taouli Bachir
Published: February 2010

Purpose:

To report our preliminary experience with the use of intravoxel incoherent motion (IVIM) diffusion‐weighted magnetic resonance imaging (DW‐MRI) and dynamic contrast‐enhanced (DCE)‐MRI alone and in combination for the diagnosis of liver cirrhosis.

Materials and Methods:

Thirty subjects (16 with noncirrhotic liver, 14 with cirrhosis) were prospectively assessed with IVIM DW‐MRI (n = 27) and DCE‐MRI (n = 20). IVIM parameters included perfusion fraction (PF), pseudodiffusion coefficient (D*), true diffusion coefficient (D), and apparent diffusion coefficient (ADC). Model‐free DCE‐MR parameters included time to peak (TTP), upslope, and initial area under the curve at 60 seconds (IAUC60). A dual input single compartmental perfusion model yielded arterial flow (Fa), portal venous flow (Fp), arterial fraction (ART), mean transit time (MTT), and distribution volume (DV). The diagnostic performances for diagnosis of cirrhosis were evaluated for each modality alone and in combination using logistic regression and receiver operating characteristic analyses. IVIM and DCE‐MR parameters were compared using a generalized estimating equations model.

Results:

PF, D*, D, and ADC values were significantly lower in cirrhosis (P = 0.0056–0.0377), whereas TTP, DV, and MTT were significantly increased in cirrhosis (P = 0.0006–0.0154). There was no correlation between IVIM‐ and DCE‐MRI parameters. The highest Az (areas under the curves) values were observed for ADC (0.808) and TTP‐DV (0.952 for each). The combination of ADC with DV and TTP provided 84.6% sensitivity and 100% specificity for diagnosis of cirrhosis.

Conclusion:

The combination of DW‐MRI and DCE‐MRI provides an accurate diagnosis of cirrhosis. J. Magn. Reson. Imaging 2010;31:589–600. © 2010 Wiley‐Liss, Inc.
Clinical evaluation of aortic coarctation with 4D flow MR imaging
Authors: Hope Michael D. , Meadows Alison K. , Hope Thomas A. , Ordovas Karen G. , Saloner David , Reddy Gautham P. , Alley Marcus T. , Higgins Charles B.
Published: February 2010

Purpose:

To show that 4D Flow is a clinically viable tool for evaluation of collateral blood flow and demonstration of distorted blood flow patterns in patients with treated and untreated aortic coarctation.

Materials and Methods:

Time‐resolved, 3D phase contrast magnetic resonance imaging (MRI) (4D Flow) was used to assess blood flow in the thoracic aorta of 34 individuals: 26 patients with coarctation (22 after surgery or stent placement) and eight healthy volunteers.

Results:

Direct comparison of blood flow calculated with 2D and 4D phase contrast data at standard levels for analysis in coarctation patients showed good correlation and agreement (correlation coefficient r = 0.99, limits of agreement = −20% to 20% for collateral blood flow calculations). Abnormal blood flow patterns were demonstrated at peak systole with 4D Flow visualization techniques in the descending thoracic aorta of patients but not volunteers. Marked helical flow was seen in 9 of 13 patients with angulated aortic arch geometries after coarctation repair. Vortical flow was seen in regions of poststenotic dilation.

Conclusion:

4D Flow is a fast and reliable means of evaluating collateral blood flow in patients with aortic coarctation in order to establish hemodynamic significance. It also can detect distorted blood flow patterns in the descending aorta after coarctation repair. J. Magn. Reson. Imaging 2010;31:711–718. © 2010 Wiley‐Liss, Inc.
MRI and S‐MRCP findings in patients with suspected chronic pancreatitis: Correlation with endoscopic pancreatic function testing (ePFT)
Authors: Balci N. Cem , Smith Adam , Momtahen Amir Javad , Alkaade Samer , Fattahi Rana , Tariq Syed , Burton Frank
Published: February 2010

Purpose:

To review magnetic resonance imaging (MRI) and secretin stimulated magnetic resonance cholangiopancreatography (S‐MRCP) findings of patients with suspected chronic pancreatitis and compare them with endoscopic pancreatic function testing (ePFT).

Materials and Methods:

MRI and S‐MRCP findings of 36 patients with clinically suspected chronic pancreatitis were reviewed. Baseline ductal changes, duodenal filling grades, and pancreatic duct caliber change (PDC) on S‐MRCP, mean values of pancreatic anteroposterior (AP) diameter, signal intensity ratio (SIR) between pancreas and the spleen on T1‐weighted fat saturated images, and arterial to venous (A/V) enhancement ratios were compared between groups of normal and abnormal pancreatic exocrine function determined by ePFT.

Results:

All patients (n = 24) with normal ePFT (HCO3 >80 mEq/L) had grade 3 normal duodenal filling. Patients with abnormal ePFT (HCO3 <80 mEq/L) (n = 12) had grade 1 (n = 1) and grade 2 (n = 11) diminished duodenal filling (P < 0.0001). PDC was 1.51 in the normal ePFT group versus 1.27 in the abnormal ePFT group (P = 0.01). No significant differences were found in terms of mean pancreatic AP diameter (21.8 vs. 19.8 cm), SIR (1.59 vs. 1.44), and A/V (1.08 vs. 1.01) between groups of normal/abnormal pancreatic exocrine function.

Conclusion:

Despite discrepancies between pancreatic exocrine function and the findings on standard MRI/MRCP, the S‐MRCP findings are comparable to ePFT in the evaluation of chronic pancreatitis. J. Magn. Reson. Imaging 2010;31:601–606. © 2010 Wiley‐Liss, Inc.
Evaluation of gadobutrol, a macrocyclic, nonionic gadolinium chelate in a brain glioma model: Comparison with gadoterate meglumine and gadopentetate dimeglumine at 1.5 T, combined with an assessment of field strength dependence, specifically 1.5 versus 3 T
Authors: Attenberger Ulrike I. , Runge Val M. , Morelli John N. , Williams Jonathan , Jackson Carney B. , Michaely Henrik J.
Published: February 2010

Purpose:

To evaluate in a rat brain glioma model intraindividual tumor enhancement at 1.5 T using gadobutrol (Gadovist), a nonionic, macrocyclic chelate currently in clinical trials in the United States, in comparison with both an ionic macrocyclic chelate, gadoterate meglumine (Dotarem), and an ionic linear chelate, gadopentetate dimeglumine (Magnevist), and to compare the degree of tumor enhancement with gadobutrol at 1.5 and 3 T.

Materials and Methods:

A total of 24 rats, divided into three groups with n = 8 animals per group, were evaluated. Animals in group 1 received injections of gadobutrol and gadopentetate dimeglumine, whereas those in group 2 received gadobutrol and gadoterate meglumine. Injections were performed in random order and separated by 24 hours. Magnetic resonance imaging (MRI) examinations were performed immediately following each contrast injection with a 1.5 T MR system. Animals in group 3 received gadobutrol injections using the same protocol but with scans performed at 1.5 and 3 T. In all examinations, T1‐weighted images were acquired precontrast, 1 minute postcontrast, and at 4 consecutive 2‐minute intervals thereafter. A contrast dose of 0.1 mmol/kg was used in all instances.

Results:

In groups 1 and 2, tumor signal‐to‐noise ratio (SNR) and contrast‐to‐noise ratio (CNR) were higher for gadobutrol compared to both other agents at each timepoint postcontrast injection. The improvement in tumor CNR with gadobutrol, depending on time, was between 12% and 40% versus gadopentetate dimeglumine, with the difference achieving statistical significance at 7 minutes. The improvement in tumor CNR with gadobutrol, depending on time, was between 15% and 27% versus gadoterate meglumine, with the difference statistically significant at 5 and 9 minutes. In group 3 the improvement in tumor SNR and CNR seen with the increase in field strength from 1.5 to 3 T for gadobutrol was statistically significant at all acquired timepoints (P < 0.002). CNR mean values ranged from 10.4 ± 2.9 to 24.6 ± 5.0 at 1.5 T and from 20.5 ± 5.9 to 47.8 ± 15.7 at 3 T depending on the timepoint postcontrast.

Conclusion:

Consistently greater tumor enhancement was noted at all measured timepoints following contrast injection with gadobutrol compared to both gadopentetate dimeglumine and gadoterate meglumine at 1.5 T. A substantial further improvement in tumor enhancement was noted using gadobutrol at 3 T. J. Magn. Reson. Imaging 2010;31:549–555. © 2010 Wiley‐Liss, Inc.
Multiparametric magnetic resonance imaging for the differentiation between benign and malignant salivary gland tumors
Authors: Eida Sato , Sumi Misa , Nakamura Takashi
Published: February 2010

Purpose:

To evaluate the stepwise approach in differentiating between benign and malignant salivary gland tumors using time‐intensity curves (TICs) and apparent diffusion coefficients (ADCs).

Materials and Methods:

TICs and ADCs were analyzed on the tumor‐by‐tumor (overall) and pixel‐by‐pixel (TIC and ADC maps) bases in patients with benign (n = 52) or malignant (n = 18) salivary gland tumor. TICs were categorized into Types 1 (<20% increment ratio), 2 (≥20% increment ratio and >120 sec peak time), 3 (≥20% increment ratio, ≤120 sec peak time, and <30% washout ratio), or 4 (≥20% increment ratio, ≤120 sec peak time, and ≥30% washout ratio). ADCs were classified as extremely low (<0.6 × 10−3 mm2/sec), low (<1.2), intermediate (<1.8), or high (≥1.8).

Results:

Malignant tumors had small (<30%) areas with Type 1 TIC with one of the following magnetic resonance imaging (MRI) characteristics: Type 3 overall TIC patterns, Type 4 overall TIC patterns and extremely low (<0.60 × 10−3 mm2/sec) overall ADCs, or Type 2 overall TIC patterns and large (>40%) areas with low or extremely low ADCs.

Conclusion:

We propose a stepwise approach by using multiparametric MRI techniques as an effective tool for differentiating between benign and malignant salivary gland tumors J. Magn. Reson. Imaging 2010;31:673–679. © 2010 Wiley‐Liss, Inc.
Fully automated reconstruction of ungated ghost magnetic resonance angiograms
Authors: Tsaftaris Sotirios A. , Offerman Erik , Edelman Robert R. , Koktzoglou Ioannis
Published: February 2010

Purpose:

To completely automate the reconstruction process during noncardiac‐gated unenhanced ghost magnetic resonance angiography (MRA).

Materials and Methods:

Ungated unenhanced ghost MRA of the calf was performed in 16 volunteers. K‐means and fuzzy c‐means (FCM) clustering algorithms using prominent image features were applied to automatically create angiograms of the calf in volunteers undergoing ungated ghost MRA. Ghost angiograms reconstructed automatically were compared to those created manually on the basis of diagnostic image quality and apparent arterial‐to‐background contrast‐to‐noise ratio (CNR). Images were also ranked by an expert user in their order of preference using an ordinal scale.

Results:

Compared with the ghost angiograms created manually, ghost angiograms reconstructed automatically with the use of clustering analysis provided similar arterial‐to‐background CNR values. No differences in diagnostic quality or preference were identified between images reconstructed manually and automatically.

Conclusion:

We present fully automated image reconstruction algorithms for use with ungated and unenhanced ghost MRA. These automated algorithms, based on the use of k‐means or FCM clustering, can be used to eliminate manual postprocessing that is time‐consuming and subject to variability. J. Magn. Reson. Imaging 2010;31:655–662. © 2010 Wiley‐Liss, Inc.
Delayed gadolinium‐enhanced MRI of cartilage in the ankle at 3 T: Feasibility and preliminary results after matrix‐associated autologous chondrocyte implantation
Authors: Domayer Stephan E. , Trattnig Siegfried , Stelzeneder David , Hirschfeld Clemens , Quirbach Sebastian , Dorotka Ronald , Nehrer Stefan , Pinker Katja , Chan Jenny , Mamisch Tallal Charles , Dominkus Martin , Welsch Götz H.
Published: February 2010

Purpose:

To demonstrate the feasibility of delayed gadolinium‐enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) in the ankle at 3 T and to obtain preliminary data on matrix associated autologous chondrocyte (MACI) repair tissue.

Materials and Methods:

A 3D dual flip angle sequence was used with an eight‐channel multipurpose coil at 3 T to obtain T1 maps both pre‐ and postintravenous contrast agent (Magnevist, 0.2 mM/kg). Postcontrast T1 over time was evaluated in three volunteers; a modified dGEMRIC protocol was then used to assess 10 cases after MACI in the ankle.

Results:

Forty‐five minutes were found sufficient for maximum T1 decrease. MACI cases had a precontrast mean T1 of 1050 ± 148.4 msec in reference cartilage (RC) and 1080 ± 165.6 msec in repair tissue (RT). Postcontrast T1 decreased to 590 ± 134.0 msec in RC and 554 ± 133.0 msec in RT. There was no significant difference between the delta relaxation rates in RT (9.44 × 10−4 s−1) and RC (8.04 × 10−4 s−1, P = 0.487). The mean relative delta relaxation rate was 1.34 ± 0.83.

Conclusion:

It is feasible to assess the thin cartilage layers of the ankle with dGEMRIC at 3 T; MACI can yield RT with properties similar to articular cartilage. J. Magn. Reson. Imaging 2010;31:732–739. © 2010 Wiley‐Liss, Inc.
Time‐resolved lower extremity MRA with temporal interpolation and stochastic spiral trajectories: Preliminary clinical experience
Authors: Lim Ruth P. , Jacob Jason S. , Hecht Elizabeth M. , Kim Danny C. , Huffman Steven D. , Kim Sooah , Babb James S. , Laub Gerhard , Adelman Mark A. , Lee Vivian S.
Published: February 2010

Purpose:

To assess added value of a new time‐resolved technique with temporal interpolation and stochastic spiral trajectory through k‐space and parallel imaging (TR‐MRA) to conventional bolus chase MRA (BC‐MRA) for infragenual peripheral artery evaluation.

Materials and Methods:

An institutional review board‐approved retrospective review of peripheral arterial disease patients was performed. Infragenual TR‐MRA and BC‐MRA were performed in 26 patients over four months. Two readers individually assessed image quality, diagnostic confidence, and stenosis severity and length in 13 defined below knee segments, first with BC‐MRA alone, and then with a combined BC‐MRA and TR‐MRA reading (BC+TR‐MRA). Perceived contribution of TR‐MRA was rated by each reader. The reference standard was a consensus reading of both sequences. Catheter angiographic (CA) correlation was available in 6 patients.

Results:

A total of 646 infragenual segments in 51 extremities were evaluated. Image quality and diagnostic confidence were superior for BC+TR‐MRA compared with BC‐MRA alone (P < 0.001). Adding TR‐MRA improved sensitivity (85.7% versus 80.7%; P < 0.05) and diagnostic accuracy (88.1% versus 85.4%; P < 0.05) for hemodynamically significant stenosis. Venous contamination (0% versus 13.1% segments) and motion (0.9% versus 8.0%) were decreased for BC+TR‐MRA versus BC‐MRA alone, P < 0.01. For BC+TR‐MRA, TR‐MRA was rated more useful than BC‐MRA in 30/51 legs (58.8%). TR‐MRA identified retrograde flow in 5 segments. Where available, there was high concordance between CA and BC+TR‐MRA (91.6%) for stenosis.

Conclusion:

Adding TR‐MRA with temporal interpolation and stochastic spiral trajectories to bolus chase MRA improves image quality, diagnostic confidence and accuracy. It provides hemodynamic information and minimizes venous contamination and patient motion. J. Magn. Reson. Imaging 2010;31:663–672. © 2010 Wiley‐Liss, Inc.
Intraoperative magnetic resonance imaging in the surgical treatment of cerebral metastases
Authors: Senft Christian , Ulrich Christian T. , Seifert Volker , Gasser Thomas
Published: February 2010

Background and Objectives

To report on the value of intraoperative magnetic resonance imaging (iMRI) in the neurosurgical treatment of cerebral metastases (CM).

Methods

We performed a total of 204 surgical procedures with the use of a mobile ultra‐low‐field iMRI‐unit. Of these, there were 12 craniotomies and 2 minimal‐invasive procedures for CM, and 63 craniotomies for glioblastoma (GBM).

Results

On intraoperative imaging, all tumors could be localized and targeted with the help of the integrated neuronavigation system. Intraoperative imaging resulted in continued tumor resection due to unexpected residual tumor tissue in 13 patients harboring GBM (20.6%), but no patient with a CM (0%). In two patients with cystic CM, iMRI helped to achieve complete collapse of cysts by means of stereotactic aspiration, relieving mass effect and allowing for adjuvant radiotherapy. All patients subsequently received adjuvant treatment according to clinical protocols.

Conclusion

Surgical resection represents one of several treatment modalities in metastatic brain disease. iMRI is useful for neuronavigation and resection control and as an adjunct in minimal‐invasive procedures in patients with CM; however, its exact value is yet to be determined by prospective randomized trials. J. Surg. Oncol. 2010; 101:436–441. © 2010 Wiley‐Liss, Inc.
Intra‐operative contrast‐enhanced ultrasound improves image enhancement in the evaluation of liver tumors
Authors: Martin Robert C.G. , Reuter Nathan P. , Woodall Charles
Published: February 2010

Background

Intra‐operative hepatic tumor ultrasound assessment can be difficult in patients with abnormal hepatic parenchyma because of the inability to enhance echogenic differences.

Methods

Prospective pilot study of intra‐operative ultrasound contrast enhancement in the evaluation of liver tumors to establish safety, dosing, and increased image enhancement with ultrasound contrast evaluation. A single bolus of perfluten lipid microspheres was then injected and ultrasound images were then re‐recorded and saved.

Results

Twenty consecutive patients underwent contrast‐enhanced ultrasound evaluation during the operative procedure. All patients received at least one bolus dose of microspheres (median 2 dose, range 1–3), without change in heart rate, blood pressure, end tidal CO2, oxygen saturation, and sedation monitoring at the time of dosing and until 4 hr post‐bolus doses. Two blinded independent readers found the contrasted images to have a statistically greater degree of enhancement (median improvement of 4, P = 0.01) and greater degree of size/border characteristics in the contrasted images (median improvement of 5, P = 0.01) for all histologies. In five patients, the extent of hepatic resection was altered from partial to complete lobectomy in order to obtain acceptable oncologic margin.

Conclusions

Contrast‐enhanced ultrasound is safe and effective in pre‐resection and pre‐ablation treatment planning. J. Surg. Oncol. 2010; 101:370–375. © 2010 Wiley‐Liss, Inc.