Compressed sensing reconstruction improves sensitivity of variable density spiral fMRI.

PURPOSE: Functional MRI (fMRI) techniques that can provide excellent blood oxygen level dependent contrast, rapid whole brain imaging, and minimal spatial distortion are in demand. This study explored whether fMRI sensitivity can be improved through the use of compressed sensing (CS) reconstruction of variable density spiral fMRI. METHODS: Three different CS-reconstructed 1-shot variable density spirals were explored (corresponding to 28%, 35%, and 46% under-sampling), and compared with conventional 1-shot and 2-shot Archimedean spirals acquired using matched echo time and volume repetition time. fMRI maps were reconstructed with or without CS MRI and sensitivity was compared using identically matched voxels. RESULTS: The results demonstrated that an l1 -norm based CS reconstruction only led to an increase in functional contrast when applied to 28% under-sampled data. A whole brain t-contrast map revealed that 2-shot uniformly sampled spiral and 28% under-sampled spiral data reconstructed with CS yield equivalent sensitivity, even with matched echo time and volume repetition time CONCLUSION: VD spiral exhibits a useful operating range, in the region of 25-30% under-sampling, for which CS reconstruction can be used to increase the sensitivity of fMRI to brain activity. Using CS, VD acquisitions achieve the same sensitivity as 2-shot Archimedean acquisitions, but require only a single shot.

Degradation and drug release in calcium polyphosphate bioceramics: an MRI-based characterization.

Degradable, bioceramic bone implants made of calcium polyphosphate (CPP) hold potential for controlled release of therapeutic agents in the treatment of localized bone disease. Magnetic resonance imaging techniques for non-invasively mapping fluid distribution, T(1) and T(2) relaxation times and the apparent diffusion coefficient were performed in conjunction with a drug elution protocol to resolve free and bound water components within the material microstructure in two CPP formulations (G1 and G2). The T(2) maps provided the most accurate estimates of free and bound water, and showed that G1 disks contained a detectable free water component at all times, with drug release dominated by a Fickian diffusion mechanism. Drug release from G2 disks was characterized by a combined diffusional/structural relaxation mechanism, which may be related to the gradual infiltration of a free water component associated with swelling and/or chemical degradation.

The ideal state for perioperative nursing.

For a typical surgical procedure, a minimum of three individuals document the care provided during the intraoperative phase. This makes it difficult to develop perioperative records with pertinent data elements without creating redundancy, errors, and inconsistencies. This article discusses strategies to develop surgical records that share information effectively through the use of structured vocabulary and a thoughtful approach to professional nursing practice. It begins to explore developing standards for paper or electronic documentation through collaboration with other stakeholders, including anesthesia care providers, surgeons, clinical directors, and informaticians.

Collecting, analyzing, and interpreting focus group data.

Conducting a focus group is only one approach to gathering information. The worthiness of the information derived from a focus group depends on many factors. The main advantage of a focus group is that it is a convenient, cost-effective, relatively fast method to collect information from a number of individuals. Useful information only can be obtained with special attention to research methods and assessment of the reliability and validity of collected data. Using a focus group should be considered when the method is appropriate to answer the research question. Remember, adequate resources and skill are required to conduct a focus group in a manner that ensures the quality of the results.

Imaging of heterogeneous materials with a turbo spin echo single-point imaging technique.

A magnetic resonance imaging method is presented for imaging of heterogeneous broad linewidth materials. This method allows for distortionless relaxation weighted imaging by obtaining multiple phase encoded k-space data points with each RF excitation pulse train. The use of this method, turbo spin echo single-point imaging-(turboSPI), leads to decreased imaging times compared to traditional constant-time imaging techniques, as well as the ability to introduce spin-spin relaxation contrast through the use of longer effective echo times. Imaging times in turboSPI are further decreased through the use of low flip angle steady-state excitation. Two-dimensional images of paramagnetic doped agarose phantoms were obtained, demonstrating the contrast and resolution characteristics of the sequence, and a method for both amplitude and phase deconvolution was demonstrated for use in high-resolution turboSPI imaging. Three-dimensional images of a partially water-saturated porous volcanic aggregate (T(2L) approximately 200 ms, Deltanu(1/2) approximately 2500 Hz) contained in a hardened white Portland cement matrix (T(2L) approximately 0.5 ms, Deltanu(1/2) approximately 2500 Hz) and a water-saturated quartz sand (T(2) approximately 300 ms, T(2)(*) approximately 800 microseconds) are shown.

Clinical practice guidelines--an organizational effort.

In response to the national trend toward developing clinical practice guidelines, AORN set out to create practice guidelines specific to perioperative nursing. In this effort, a designated group of individuals began defining and reviewing guidelines from other organizations and determining parameters for developing AORN's own patient-focused, comprehensive, research-based guidelines. Clinical practice guidelines now have been published in AORN's Standards, Recommended Practices, and Guidelines, and a template has been established to help other AORN members create and implement guidelines for clinical conditions, common procedures, or patient populations specific to perioperative nursing practice.

Perioperative data elements: interventions and outcomes.

In 1999, the American Nurses Association's committee on nursing practice recognized AORN's Perioperative Nursing Data Set (PNDS) as a data set useful in the practice of nursing. The PNDS is a standardized nursing language specific to perioperative settings that is both clinically relevant and empirically validated. This data set is the culmination of six years of effort by AORN and AORN staff members to develop a standardized language that is clearly defined, common to all cases, and consistent across time.

Clinical expertise and research findings--understanding the fit.

Clinical expertise is as valuable as the information that supports decisions. The worth of that information must be evaluated carefully and constantly questioned. Clinicians must work together to carefully and systematically analyze what they bring to the decision-making process. Rules that serve as the foundation of one's decision need to be evaluated continuously. As well, every clinician must be aware of inherent and subtle biases that influence decisions. Relying on clinical expertise can be a helpful strategy, but clinicians must proceed with caution. As with research, nothing is correct 100% of the time--even experts make mistakes. Use your expertise to determine what strategy is correct when facing a clinical problem. If your clinical expertise will serve the patient best, do not be afraid to use this hard-earned knowledge for the optimum patient outcome.

Structural data elements--standardized terms and definitions.

Perioperative nurses must have an organized approach to collect, organize, classify, and capture clinical nursing data to communicate nursing practice. Standardized nursing language provides a systematic method of collecting basic elements of perioperative nursing care. This article examines how structural elements were developed and validated for this standardized language.