Radiofrequency interference in magnetic resonance imaging: Identification and rectification.

Radiofrequency (RF) interference artifact is a common type of magnetic resonance imaging (MRI) artifacts caused by the presence of unwanted RF field inside the scanner room. The artifact has the appearance of parallel bright lines or bands that resemble zippers, which can mimic pathology, obstruct the viewing of underlining tissues, and lower image signal-to-noise ratio, affecting the diagnostic evaluation of the image and sometimes even rendering it non-diagnostic. Due to the presence of multiple possible sources of RF interference in MRI and potential nonrelated MRI artifacts that resemble RF interference artifact, it may be difficult to effectively and timely resolve the artifact problem.

Basic Principles of and Practical Guide to Clinical MRI Radiofrequency Coils.

Radiofrequency (RF) coils are an essential MRI component used for transmission of the RF field to excite nuclear spins and for reception of the MRI signal. They play an important role in image quality in terms of signal-to-noise ratio, signal uniformity, and image resolution. However, they are also associated with potential image artifacts and RF heating that may lead to patient burns.

Spike protein multiorgan tropism suppressed by antibodies targeting SARS-CoV-2.

While there is SARS-CoV-2 multiorgan tropism in severely infected COVID-19 patients, it's unclear if this occurs in healthy young individuals. In addition, for antibodies that target the spike protein (SP), it's unclear if these reduce SARS-CoV-2/SP multiorgan tropism equally. We used fluorescently labeled SP-NIRF to study viral behavior, using an in vivo dynamic imaging system and ex in vivo tissue analysis, in young mice.

Cerebrospinal fluid drainage kinetics across the cribriform plate are reduced with aging.

Background: Continuous circulation and drainage of cerebrospinal fluid (CSF) are essential for the elimination of CSF-borne metabolic products and neuronal function. While multiple CSF drainage pathways have been identified, the significance of each to normal drainage and whether there are differential changes at CSF outflow regions in the aging brain are unclear.

Methods: Dynamic in vivo imaging of near infrared fluorescently-labeled albumin was used to simultaneously visualize the flow of CSF at outflow regions on the dorsal side (transcranial and -spinal) of the central nervous system.

A Comparative Study of High-Resolution Chemical-Shift-Eliminated Magnetic Resonance Imaging of Finger Specimens with Microcomputed Tomography.

Objective: High-resolution images of finger joints with chemical-shift elimination can be obtained using an interleaved water-fat (IWF) sequence. This study assessed IWF imaging of finger joints in the delineation of bone structures by comparing images of cadaver fingers with those of microcomputed tomography (CT) that served as a standard reference.

Materials And Methods: IWF images with spatial resolution of 176 µ × 176 µ × 300 µ were obtained from the distal and proximal interphalangeal joints of two cadaver finger specimens using a custom-built radiofrequency receive coil at 1.

In Vivo Measurement of the Human Lumbar Spine Using Magnetic Resonance Imaging to Ultrasound Registration.

Objective: This study aimed to refine a magnetic resonance imaging (MRI)-ultrasound registration (ie, alignment) technique to make noninvasive, nonionizing, 3-dimensional measurement of the lumbar segmental motion in vivo.

Methods: Five healthy participants participated in this validation study. We scanned the lumbar region of each participant 5 times using an ultrasound probe while he or she kept a prone lying posture on a plinth.

A non-ionizing technique for three-dimensional measurement of the lumbar spine.

Comprehensive assessments of scoliotic deformity and spinal instability require repetitive three-dimensional (3D) measurements of motion segments at different functional postures. However, accurate 3D measurement of the spine is a challenging task. In this paper, we present a novel, non-invasive, non-ionizing technique to quantify 3D poses of lumbar motion segments in terms of clinically meaningful anatomical coordinates.

Hierarchical CT to Ultrasound Registration of the Lumbar Spine: A Comparison with Other Registration Methods.

Three-dimensional (3D) measurement of the spine can provide important information for functional, developmental, diagnostic, and treatment-effect evaluations. However, existing measurement techniques are either 2-dimensional, highly invasive, or involve a high radiation dose, prohibiting their widespread and repeated use in both research and clinical settings. Non-invasive, non-ionizing, 3D measurement of the spine is still beyond the current state-of-the-art.

A method of switching the signal in an MRI phantom based on trace ion currents.

A method for electrically changing the hydrogen nuclear magnetic resonance (NMR) signal intensity in a magnetic resonance imaging (MRI) phantom is presented. The method is based on creating local magnetic field inhomogeneities from impurity ion currents in a polar hydrocarbon. The effect is demonstrated using the propylene carbonate on an NMR spectrometer and an MRI scanner.

High-resolution interleaved water-fat MR imaging of finger joints with chemical-shift elimination.

Purpose: To study the use of an interleaved water-fat (IWF) sequence with a custom-made radiofrequency (RF) coil for high-resolution imaging of arthritic finger joints.

Materials And Methods: High-resolution finger magnetic resonance imaging (MRI) was performed using a custom-made dedicated RF receiver coil and an IWF sequence. A phantom, a cadaver finger specimen, and the fingers of two normal controls and six arthritic subjects were imaged with a resolution of 156 × 156 × 600 μm.

High-resolution uniform MR imaging of finger joints using a dedicated RF coil at 3T.

Purpose: To develop a dedicated radiofrequency (RF) coil for high-resolution magnetic resonance imaging (MRI) of finger joints at 3T to improve diagnostic evaluation of arthritic diseases.

Materials And Methods: A dedicated cylindrical RF receive coil was developed for imaging finger joints at 3T. A planar coil, a saddle coil, and a 1.

In vivo MRI using liquid nitrogen cooled phased array coil at 3.0 T.

A liquid nitrogen (LN2) cooled dual-channel array coil was designed and built for use on a 3.0-T whole-body scanner. In vivo imaging of a volunteer's fingers and imaging of a deceased mouse and oil phantom were performed using the LN2 cooled array and a similar room-temperature coil.

A four-element phased array coil for high resolution and parallel MR imaging of the knee.

A four-element phased array coil for MR imaging of the knee was designed, built and tested for clinical use at 1.5 Tesla. In routine imaging, it provides over twofold increase in signal-to-noise (SNR) compared to two commercially available knee coils, and supports higher spatial image resolution.