Reaching Adolescents for Prevention: The Role of Pediatric Emergency Department Health Promotion Advocates.

Objectives: Almost 200,000 adolescents visit US emergency departments (EDs) yearly for conditions involving underage drinking but receive no follow-up referral. Other health risk behaviors resulting in sexually transmitted infections, car crashes, and assault-related injury are common among adolescents. A pediatric ED (PED) visit presents an opportunity to discuss and promote prevention.

The DTI Challenge: Toward Standardized Evaluation of Diffusion Tensor Imaging Tractography for Neurosurgery.

Background And Purpose: Diffusion tensor imaging (DTI) tractography reconstruction of white matter pathways can help guide brain tumor resection. However, DTI tracts are complex mathematical objects and the validity of tractography-derived information in clinical settings has yet to be fully established. To address this issue, we initiated the DTI Challenge, an international working group of clinicians and scientists whose goal was to provide standardized evaluation of tractography methods for neurosurgery.

Assessment of the learning environment in prosthodontic department based on Dental College Learning Environment Survey by the graduates of a dental institute in India.

The purpose of this study was to determine dental graduates' perceptions of learning environment in a prosthodontic department in a dental institute in India. The 60-item closed-ended, cross-sectional questionnaire with five options was completed by the dental graduates and the dentists. The data obtained was analyzed using statistical software.

Lung Parenchymal Signal Intensity in MRI: A Technical Review with Educational Aspirations Regarding Reversible Versus Irreversible Transverse Relaxation Effects in Common Pulse Sequences.

Lung parenchyma is challenging to image with proton MRI. The large air space results in ~l/5th as many signal-generating protons compared to other organs. Air/tissue magnetic susceptibility differences lead to strong magnetic field gradients throughout the lungs and to broad frequency distributions, much broader than within other organs.

Clinical application of pharmacokinetic analysis as a biomarker of solitary pulmonary nodules: dynamic contrast-enhanced MR imaging.

The purpose of this study is to evaluate perfusion indices and pharmacokinetic parameters in solitary pulmonary nodules (SPNs). Thirty patients of 34 enrolled with SPNs (15-30 mm) were evaluated in this study. T1 and T2-weighted structural images and 2D turbo FLASH perfusion images were acquired with shallow free breathing.

Impact of nonrigid motion correction technique on pixel-wise pharmacokinetic analysis of free-breathing pulmonary dynamic contrast-enhanced MR imaging.

Purpose: To investigates the impact of nonrigid motion correction on pixel-wise pharmacokinetic analysis of free-breathing DCE-MRI in patients with solitary pulmonary nodules (SPNs). Misalignment of focal lesions due to respiratory motion in free-breathing dynamic contrast-enhanced MRI (DCE-MRI) precludes obtaining reliable time-intensity curves, which are crucial for pharmacokinetic analysis for tissue characterization.

Materials And Methods: Single-slice 2D DCE-MRI was obtained in 15 patients.

Diffusion-weighted MRI of malignant pleural mesothelioma: preliminary assessment of apparent diffusion coefficient in histologic subtypes.

Objective: The purpose of this study was to prospectively assess, in the evaluation of patients with suspected malignant pleural mesothelioma (MPM), apparent diffusion coefficient (ADC) values derived from diffusion-weighted images obtained with a free-breathing single-shot spin-echo echo-planar imaging sequence and to correlate the ADC values with the three histologic subtypes of MPM.

Subjects And Methods: Sixty-two patients with a known pleural abnormality and clinical findings suggestive of MPM underwent diffusion-weighted 3-T MRI and ADC calculation. The pathologic diagnosis was confirmed by surgical procedure.

Techniques for automatic spinal cord histology characterization for validation of diffusion tensor imaging.

One current focus in diffusion tensor imaging is the validation of DT-MR measurements against histological slices. Current methods require manual correlation by visual inspection. We present algorithms which automatically analyze spinal cord histology slices based on Fourier and morphological operators.

Collateral nerve fibers in human spinal cord: visualization with magnetic resonance diffusion tensor imaging.

Diffusion tensor magnetic resonance imaging provides structural information about nerve fiber tissue. The first eigenvector of the diffusion tensor is aligned with the nerve fibers, i.e.

Diffusion tensor imaging of the spinal cord.

The spinal cord is an important part of the nervous system and provides the connection of the brain with the periphery. It consists not only of a large number of longitudinal fibers, but also contains collateral fibers and a central gray matter structure, which are part of autonomous circuits. Magnetic resonance diffusion tensor imaging can reveal this complex fiber architecture in great detail.

Apparent diffusion coefficient and fractional anisotropy in spinal cord: age and cervical spondylosis-related changes.

Purpose: To present the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) change with age in the normal spinal cord and in cervical spondylosis.

Materials And Methods: A total of 11 normal volunteers and 79 cervical spondylosis patients entered this study. Line scan diffusion tensor images were obtained in a 1.

In vivo visualization of white matter fiber tracts of preterm- and term-infant brains with diffusion tensor magnetic resonance imaging.

Objective: The goal of this study was to test the feasibility of visualizing a 3-dimensional structure of cerebral white matter fiber tracts in preterm infants, postconceptional age (PCA) 28 weeks to term, by using volumetric diffusion tensor magnetic resonance imaging (DTI) data.

Materials And Method: We combined tractography algorithms and visualization methods, currently available for adult DTI data, to trace the pixelated principal direction of a diffusion tensor originating from regions-of-interest with high fractional anisotropy. Consequently, white matter fiber bundles from the genu and the splenium of corpus callosum, the corticospinal tracts, the inferior fronto-occipital fasciculi, and optic radiations were visualized.

Characterization of central nervous system structures by magnetic resonance diffusion anisotropy.

Diffusion-weighted magnetic resonance imaging (MRI) provides information about tissue water diffusion. Diffusion anisotropy, which can be measured with diffusion tensor MRI, is a quantitative measure of the directional dependence of the diffusion restriction that is introduced by biological structures such as nerve fibers. Diffusion tensor MRI data was obtained in the brain, brain stem, and cervical spinal cord.

Comparison of single-shot echo-planar and line scan protocols for diffusion tensor imaging.

Rationale And Objectives: Both single-shot diffusion-weighted echo-planar imaging (EPI) and line scan diffusion imaging (LSDI) can be used to obtain magnetic resonance diffusion tensor data and to calculate directionally invariant diffusion anisotropy indices, ie, indirect measures of the organization and coherence of white matter fibers in the brain. To date, there has been no comparison of EPI and LSDI. Because EPI is the most commonly used technique for acquiring diffusion tensor data, it is important to understand the limitations and advantages of LSDI relative to EPI.

Biexponential diffusion tensor analysis of human brain diffusion data.

Several studies have shown that in tissues over an extended range of b-factors, the signal decay deviates significantly from the basic monoexponential model. The true nature of this departure has to date not been identified. For the current study, line scan diffusion images of brain suitable for biexponential diffusion tensor analysis were acquired in normal subjects on a clinical MR system.

Intraoperative magnetic resonance imaging and magnetic resonance imaging-guided therapy for brain tumors.

Since their introduction into surgical practice in the mid 1990s, intraoperative MRI systems have evolved into essential, routinely used tools for the surgical treatment of brain tumors in many centers. Clear delineation of the lesion, "under-the-surface" vision, and the possibility of obtaining real-time feedback on the extent of resection and the position of residual tumor tissue (which may change during surgery due to "brain-shift") are the main strengths of this method. High-performance computing has further extended the capabilities of intraoperative MRI systems, opening the way for using multimodal information and 3D anatomical reconstructions, which can be updated in "near real time.

Characterization of normal brain and brain tumor pathology by chisquares parameter maps of diffusion-weighted image data.

Objective: To characterize normal and pathologic brain tissue by quantifying the deviation of diffusion-related signal from a simple monoexponential decay, when measured over a wider than usual range of b-factors.

Methods And Materials: Line scan diffusion imaging (LSDI), with diffusion weighting at multiple b-factors between 100 and 5000 s/mm(2), was performed on 1.5 T clinical scanners.

Diffusion tensor imaging and its application to neuropsychiatric disorders.

Magnetic resonance diffusion tensor imaging (DTI) is a new technique that can be used to visualize and measure the diffusion of water in brain tissue; it is particularly useful for evaluating white matter abnormalities. In this paper, we review research studies that have applied DTI for the purpose of understanding neuropsychiatric disorders. We begin with a discussion of the principles involved in DTI, followed by a historical overview of magnetic resonance diffusion-weighted imaging and DTI and a brief description of several different methods of image acquisition and quantitative analysis.

Processing and visualization for diffusion tensor MRI.

This paper presents processing and visualization techniques for Diffusion Tensor Magnetic Resonance Imaging (DT-MRI). In DT-MRI, each voxel is assigned a tensor that describes local water diffusion. The geometric nature of diffusion tensors enables us to quantitatively characterize the local structure in tissues such as bone, muscle, and white matter of the brain.

High-resolution line scan diffusion tensor MR imaging of white matter fiber tract anatomy.

Background And Purpose: MR diffusion tensor imaging permits detailed visualization of white matter fiber tracts. This technique, unlike T2-weighted imaging, also provides information about fiber direction. We present findings of normal white matter fiber tract anatomy at high resolution obtained by using line scan diffusion tensor imaging.

Normal brain and brain tumor: multicomponent apparent diffusion coefficient line scan imaging.

Magnetic resonance line scan diffusion imaging of the brain, with diffusion weighting between 5 and 5,000 sec/mm(2), was performed in healthy subjects and patients with a 1.5-T machine. For each voxel, biexponential signal decay fits produced two apparent diffusion constants and respective signal amplitudes.

Motion robust imaging for continuous intraoperative MRI.

The sensitivity of MR imaging to motion and susceptibility normally requires that the physician using intraoperative MRI cease surgical activity while image data sets are acquired. We demonstrate that line scan imaging allows the physician to continue operating without the delays caused by imaging. Consequently, patient anesthesia, surgery, and operating room time can be reduced.

Intraoperative diffusion imaging on a 0.5 Tesla interventional scanner.

Intraoperative line scan diffusion imaging (LSDI) on a 0.5 Tesla interventional MRI was performed during neurosurgery in three patients. Diffusion trace images were obtained in acute ischemic cases.

Application and validation of three-dimensional data sets from a phase contrast MR angiography for preoperative computer simulation of brain tumors.

We applied a three-dimensional (3D) phase contrast magnetic resonance angiography as the source for generating integrated 3D images for surgical planning of brain tumors. In the 3D model, we defined the Cingulomarginal sulcus and subsequently the central sulcus in the interhemispheric plane. This method solved the misregistration problem caused by the combination of multi-sequence data sets and can be feasible for surgical planning.