OBJECTIVES/HYPOTHESIS: To evaluate airway sufficiency and airflow dynamics in a group of patients who underwent a posterior transverse laser cordotomy (PTLC) procedure. STUDY DESIGN: Mixed methods research, university hospital setting. METHODS: Sixteen patients who underwent a PTLC procedure volunteered to be involved in this study. Dyspnea levels, voice, and glottic ...

The combination of Pt with Co either in alloy or in multilayer form is widely studied among the potential magnetic media for ultrahigh density magnetic recording. On the other hand the combination of Co with Cr in alloy form is currently providing commercial magnetic media. In an effort to further ...

To assess the feasibility of multiple-bolus dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in the pancreas; to optimize the analysis; and to investigate application of the method to a glucose challenge in type 2 diabetes. A 4-bolus DCE-MRI protocol was performed on five patients with type 2 diabetes and 11 ...

the aim of this pilot study was to demonstrate physiological movements of the muscular walls surrounding the abdominal cavity during breathing and coughing in healthy nulliparous women by means of real-time dynamic magnetic resonance imaging (MRI). eight volunteers underwent MRI measurements in a 1.5-T whole body MR-scanner. Coronal and sagittal ...

Focused ultrasound (FUS) in conjunction with microbubbles has been shown to successfully open the blood-brain barrier (BBB) in the mouse brain. In this study, we compute the BBB permeability after opening in vivo. The spatial permeability of the BBB-opened region was assessed using dynamic contrast-enhanced MRI (DCE-MRI). The DCE-MR images ...

Epitaxial Py/Cu/Co/Cu(001) trilayers were patterned into micron sized disks and imaged using element-specific photoemission electron microscopy. By varying the Cu spacer layer thickness, we study how the coupling between the two magnetic layers influences the formation of magnetic vortex states. We find that while the Py and Co disks form ...

An unusual magnetoresistance (MR) behavior in Sr(2)FeMoO(6), recently termed as spin-valve-type MR (SVMR), presents several anomalies that are little understood so far. The formation of a magnetically distorted skin layer around every soft, ferromagnetic grain seems to be the reason behind such an unprecedented tunneling MR (TMR) response. However, initially ...

The purpose of this study was to determine the impact of water exchange on tracer kinetic parameter estimates derived from T(1)-weighted dynamic contrast-enhanced (DCE)-MRI data using a direct quantitative comparison with DCE-CT. Data were acquired from 12 patients with bladder cancer who underwent DCE-CT followed by DCE-MRI within a week. ...

One of the current limitations of dynamic contrast-enhanced MR angiography is the requirement of both high spatial and high temporal resolution. Several undersampling techniques have been proposed to overcome this problem. However, in most of these methods the tradeoff between spatial and temporal resolution is constant for all the time ...

To evaluate the efficacy of discriminant function analysis of perirectal tumor infiltration with dynamic contrast-enhanced 64-detector row CT in rectal cancer. Forty-nine patients with rectal cancer underwent dynamic contrast-enhanced CT. A total of 96 axial CT slices containing the tumors were evaluated. The 96 images were separated into two groups ...

PURPOSE: To prospectively determine mural perfusion dynamics in patients with untreated celiac disease by using dynamic contrast material-enhanced magnetic resonance (MR) imaging and to compare these dynamics with those in a control population and in patients with celiac disease treated with a gluten-free diet. MATERIALS AND METHODS: Institutional review board ...

Biomarkers that can predict the outcome of treatment accurately are needed for treatment individualization in advanced carcinoma of the uterine cervix. The potential of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was investigated in the present preclinical study. CK-160 and TS-415 human cervical carcinoma xenografts were subjected to DCE-MRI at 1.5T ...

Conventional magnetic resonance (MR) imaging has limited capacity to differentiate between glioblastoma multiforme (GBM) and metastasis. The purposes of this study were: (1) to compare microvascular leakage (MVL), cerebral blood volume (CBV), and blood flow (CBF) in the distinction of metastasis from GBM using dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging ...

An alternative prevascularized bed with a subcutaneously located entrance would substantially improve islet engraftment, requiring much less invasive surgery. Studies have described times necessary for the creation of an artificial pouch suitable for subsequent islet transplantation. Polymeric mesh shaped in rounded scaffolds were implanted both subcutaneously and into the major ...

Dynamic contrast-enhanced computed tomography (DCE-CT) is a quantitative technique that employs rapid sequences of CT images after bolus administration of intravenous contrast material to measure a range of physiological processes related to the microvasculature of tissues. By combining knowledge of the molecular processes underlying changes in vascular physiology with an ...

PURPOSE: To compare two DeltaR2* quantification methods for analyzing the response of intracranial tumors to different breathing gases. The determination of changes in the magnetic resonance imaging (MRI) relaxation rate R2* (DeltaR2*), induced by hyperoxic and hypercapnic respiratory challenges, enables the noninvasive assessment of blood oxygenation changes and vasoreactivity. MATERIALS ...

Dynamic contrast-enhanced MRI is extensively studied to define and evaluate biomarkers for early assessment of vasculature-targeting therapies. In this study, two-dimensional and three-dimensional radial multi-gradient-echo techniques for dynamic R*(2)-corrected R(1) mapping based on the spoiled gradient recalled signal equation were implemented and validated at 4.7 T. The techniques were evaluated ...

AIMS AND BACKGROUND: To assess the diagnostic accuracy of magnetic resonance imaging in local staging of endometrial carcinoma, and to review the results and pitfalls described in the literature. METHODS: Thirty women with a histological diagnosis of endometrial carcinoma underwent magnetic resonance imaging. Unenhanced T2-weighted and dynamic contrast-enhanced Ti-weighted sequences ...

OBJECTIVES: To determine the feasibility of a dynamic CT angiography-protocol in regard to simultaneous assessment of morphology and function. METHOD AND MATERIALS: Fourteen patients with renal graft dysfunction received a dynamic computed tomography angiography (CTA) using a 128-slice CT-scanner with continuous bi-directional table movement, allowing to cover a scan range ...

To present an unenhanced four-dimensional time-resolved dynamic magnetic resonance (MR) angiography technique with true fast imaging with steady-state precession-based spin tagging with alternating radiofrequency (STAR), also called TrueSTAR. This study received Institutional Review Board approval and was HIPAA compliant. Informed consent was obtained from all study subjects. In eight healthy ...

PURPOSE: This study was undertaken to clinically validate the accuracy of a semiautomated software tool for analysing the enhancement curve in focal malignant bone lesions. MATERIALS AND METHODS: Twenty-three patients affected by cancer with malignant focal bone lesions underwent dynamic gadolinium-enhanced magnetic resonance (MR) imaging using the following protocol: T1-weighted ...

This study seeks to quantify differences in anterior vaginal wall prolapse during sequential Valsalva attempts on dynamic magnetic resonance imaging (MRI). Subjects were taken from an on-going case-control study evaluating anterior vaginal wall prolapse. Women with a prolapse whose leading edge extended >or=1 cm beyond the hymenal ring were included ...

PURPOSE: To prospectively evaluate the utility of dynamic contrast material-enhanced magnetic resonance (MR) imaging in predicting the response of locally advanced pancreatic cancer to combined chemotherapy and antiangiogenic therapy. MATERIALS AND METHODS: This prospective, institutional review board-approved, HIPAA-compliant study with informed consent assessed dynamic contrast-enhanced MR imaging in 11 patients ...

We aimed to show the diagnostic performance of magnetic resonance imaging by comparing T2-weighted images and dynamic 3D MR images in the assessment of myometrial and cervical invasion by endometrial carcinoma. This prospective study included 53 women consecutively diagnosed with endometrial carcinoma. The subjects were evaluated by TSE T2-weighted images ...

PURPOSE: To compare two magnetic resonance (MR) contrast mechanisms, R*(2) BOLD and balanced SSFP, for the dynamic monitoring of the cerebral response to (C)O(2) respiratory challenges. MATERIALS AND METHODS: Carbogen and CO(2)-enriched air were delivered to 9 healthy volunteers and 1 glioblastoma patient. The cerebral response was recorded by two-dimensional ...

Cervical tumors of 38 cervix cancer patients were scanned by T(1)-weighted dynamic contrast enhanced (DCE) MRI and then by DCE-CT on the same day. Gadodiamide and iohexol were respectively used as the low-molecular-weight contrast agent in DCE-MRI and DCE-CT. Under an extended Tofts model, DCE-MRI data were analyzed using either ...

PURPOSE: To characterize rounded atelectasis (RA) with dynamic contrast-enhanced MRI in the differential diagnosis of solitary peripheral pulmonary neoplasm. MATERIALS AND METHODS: Twenty-four patients with diagnostically equivocal peripheral pulmonary nodules were examined with dynamic contrast-enhanced MRI. 13 patients had a total of 16 rounded atelectases and 11 had a neoplasm. ...

Targeted therapy has significantly improved the perspectives of patients with metastatic renal cell cancer (mRCC). Frequently, these new molecules cause disease stabilization rather than substantial tumor regression. As treatment options expand with the growing number of targeted agents, there is an increasing need for surrogate markers to early assess tumor ...

OBJECTIVES: In cardiac perfusion examinations with computed tomography (CT) large concentrations of iodine in the ventricle and in the descending aorta cause beam hardening artifacts that can lead to incorrect perfusion parameters. The aim of this study is to reduce these artifacts by performing an iterative correction and by accounting ...

The most recent and significant magnetic resonance imaging (MRI) improvements allow for the visualization of the vocal tract during speech production, which has been revealed to be a powerful tool in dynamic speech research. However, a synchronization technique with enhanced temporal resolution is still required. The study design was transversal ...

Solid tumors are characterized by abnormal blood vessel organization, structure, and function. These abnormalities give rise to enhanced vascular permeability and may predict therapeutic responses. The permeability and architecture of the microvasculature in human osteosarcoma tumors growing in dorsal window chambers in athymic mice were measured by confocal laser scanning ...

Compared to gold-standard measurements of cerebral perfusion with positron emission tomography using H(2)[(15)O] tracers, measurements with dynamic susceptibility contrast MR are more accessible, less expensive, and less invasive. However, existing methods for analyzing and interpreting data from dynamic susceptibility contrast MR have characteristic disadvantages that include sensitivity to incorrectly modeled ...

PURPOSE: The aim of this study was to evaluate the accuracy of dynamic gadolinium (Gd)-enhanced magnetic resonance imaging (MRI) with endorectal coil for assessing tumor invasion based on simple classification criteria. MATERIALS AND METHODS: A total of 58 patients with operable primary rectal cancer underwent preoperative MRI. An enhancement pattern ...

To evaluate the effectiveness of contrast-enhanced ultrasonography (CEUS) using Sonazoid for the diagnosis of the local recurrence after treatment for hepatocellular carcinoma (HCC) by comparing it with dynamic CT. Seventy-one patients with 87 HCC lesions (mean +/- SD; 19.5 +/- 9.6 mm) underwent CEUS using Sonazoid and dynamic CT after ...

The key element in drug release from hydrophilic matrix tablets is the gel layer that regulates the penetration of water and controls drug dissolution and diffusion. We have selected magnetic resonance imaging (MRI) as the method of choice for visualizing the dynamic processes occurring during the swelling of xanthan tablets ...

The purpose of the study was to assess the usefulness of dynamic MRI in patients with pelvic organ prolapse after pelvic floor repair with polypropylene mesh. Fifteen consecutive patients (mean age 66.5 years) who were scheduled for either anterior (n=9) or posterior (n=6) pelvic floor repair were prospectively evaluated by ...

With the advent of dynamic fast MRI sequences the act of deglutition can be dynamically visualized in cine-mode. Twenty-three healthy volunteers were enrolled in this study to define the morpho-functional patterns of oral and pharyngeal deglutition using new dynamic MRI techniques. All subjects were previously submitted to video endoscopic assessment, ...

The most common methods for measuring perfusion with MRI are arterial spin labelling (ASL), dynamic susceptibility contrast (DSC-MRI), and T(1)-weighted dynamic contrast enhancement (DCE-MRI). This review focuses on the latter approach, which is by far the most common in the body and produces measures of capillary permeability as well. The ...

Inflammatory bowel disease, including ulcerative colitis, is characterized by persistent or recurrent inflammation and can progress to colon cancer. Colitis is difficult to detect and monitor noninvasively. The goal of this work was to develop a preclinical imaging method for evaluating colitis. Herein, we report improved MRI methods for detecting ...

The aim of this study was to develop and demonstrate a methodology for dynamic contrast-enhanced MRI at 3 T in patients with advanced ovarian cancer and to report the results from pharmacokinetic modeling of the data. Nineteen patients with suspected advanced ovarian carcinoma (FIGO stage 3 or higher) were enrolled ...

The purpose of this study was to (1) depict normal dynamic swallowing and (2) measure (a) the temporal characteristics of three components of laryngeal closure, i.e., true vocal cord (TVC) closure, closure of the laryngeal vestibule at the arytenoid to epiglottic base, and epiglottic inversion, and (b) the temporal relationship ...

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 ...

This paper presents a new method for improved flow analysis and quantification using MRI. The method incorporates fluid dynamics to regularize the flow quantification from tagged MR images. Specifically, the flow quantification is formulated as a minimization problem based on the following: 1) the Navier-Stokes equation governing the fluid dynamics; ...

The aim of this dynamic magnetic resonance (MR) imaging study was to assess the relation between the position and mobility of the perineum and patients' symptoms of pelvic floor dysfunction. Patients' symptoms were measured with the use of validated questionnaires. Univariate logistic regression analyses were used to study the relationship ...

PURPOSE: To prospectively evaluate magnetic resonance (MR) imaging including dynamic contrast-enhanced MR imaging in the differentiation of benign from malignant orbital masses and to evaluate which MR imaging features are most predictive of malignant tumors. MATERIALS AND METHODS: The study was approved by the institutional review board and signed informed ...

PURPOSE: To retrospectively assess an improved quantitative methodology with separate assessment of perfusion and permeability for characterization of primary renal cell carcinoma (RCC) and monitoring antiangiogenic treatment. MATERIALS AND METHODS: Fifteen RCC patients before surgery, 6 RCC patients before and after neoadjuvant antiangiogenic therapy, and 15 patients without renal disease ...

PURPOSE: To compare posttreatment bone marrow changes at whole-body dynamic contrast material-enhanced magnetic resonance (MR) imaging with clinical response in patients with multiple myeloma (MM) and to determine if this technique can be used to assess treatment response in patients with MM. MATERIALS AND METHODS: This study was approved by ...

Canonical transformation (CT) theory describes dynamic correlation in multireference systems with large active spaces. Here we discuss CT theory's intruder state problem and why our previous approach of overlap matrix truncation becomes infeasible for sufficiently large active spaces. We propose the use of strongly and weakly contracted excitation operators as ...

The purpose of this study was to evaluate the use of dynamic contrast-enhanced (DCE) MRI, in vivo (1)H MRS and ex vivo high resolution magic angle spinning (HR MAS) MRS of tissue samples as methods to detect early treatment effects of docetaxel in a breast cancer xenograft model (MCF-7) in ...

Patients presenting with primary evacuatory difficulty have a multiplicity of pelvic floor and perineal soft tissue anomalies. The radiological assessment of these patients requires modalities which monitor the dynamic interaction of pelvic organs during provocative manoeuvres such as straining and simulated defaecation. The advantages and disadvantages of these complementary modalities, ...