1.5 T augmented reality navigated interventional MRI: paravertebral sympathetic plexus injections.

Purpose: The high contrast resolution and absent ionizing radiation of interventional magnetic resonance imaging (MRI) can be advantageous for paravertebral sympathetic nerve plexus injections. We assessed the feasibility and technical performance of MRI-guided paravertebral sympathetic injections utilizing augmented reality navigation and 1.5 T MRI scanner.

MR-guided perineural injection of the ganglion impar: technical considerations and feasibility.

Objective: Perineural ganglion impar injections are used in the management of pelvic pain syndromes; however, there is no consensus regarding the optimal image guidance. Magnetic resonance imaging (MRI) provides high soft tissue contrast and the potential to directly visualize and target the ganglion. The purpose of this study was to assess the feasibility of MR-guided percutaneous perineural ganglion impar injections.

Fused X-ray and MR imaging guidance of intrapericardial delivery of microencapsulated human mesenchymal stem cells in immunocompetent swine.

Purpose: To assess intrapericardial delivery of microencapsulated, xenogeneic human mesenchymal stem cells (hMSCs) by using x-ray fused with magnetic resonance (MR) imaging (x-ray/MR imaging) guidance as a potential treatment for ischemic cardiovascular disease in an immunocompetent swine model.

Materials And Methods: All animal experiments were approved by the institutional animal care and use committee. Stem cell microencapsulation was performed by using a modified alginate-poly-l-lysine-alginate encapsulation method to include 10% (wt/vol) barium sulfate to create barium-alginate microcapsules (BaCaps) that contained hMSCs.

MR-guided vertebroplasty with augmented reality image overlay navigation.

Purpose: To evaluate the feasibility of magnetic resonance imaging (MRI)-guided vertebroplasty at 1.5 Tesla using augmented reality image overlay navigation.

Materials And Methods: Twenty-five unilateral vertebroplasties [5 of 25 (20%) thoracic, 20 of 25 (80%) lumbar] were prospectively planned in 5 human cadavers.

Patellofemoral friction syndrome: magnetic resonance imaging correlation of morphologic and T2 cartilage imaging.

Objective: This study aimed to investigate whether patellofemoral T2 cartilage changes are associated with lateral patellofemoral friction syndrome (PFS), as indicated by an edema-like signal within the superolateral infrapatellar (Hoffa) fat pad.

Methods: In this institutional review board-approved retrospective study of 510 consecutive patients, 49 patients with 50 knee magnetic resonance imaging examinations demonstrating normal or low-grade patellofemoral cartilage abnormalities (whole-organ magnetic resonance imaging score [WORMS] score, ≤2) were included. Twenty-two examinations with PFS (cases) were compared with an age- and sex-matched cohort of 28 examinations without PFS (controls).

Magnetic resonance neurography: technical considerations.

Proper performance of magnetic resonance neurography (MRN) is essential not only to make the examination easier to interpret but also for its accurate evaluation. This article outlines the technical considerations of MRN, various imaging pulse sequences available on current scanners, as well as their relative advantages and disadvantages. In addition, a guide to the optimal use of high-resolution and high-contrast MRN technique is provided, which will aid clinicians in attaining a good-quality examination.

4D tumor centroid tracking using orthogonal 2D dynamic MRI: implications for radiotherapy planning.

Purpose: Current pretreatment, 4D imaging techniques are suboptimal in that they sample breathing motion over a very limited "snapshot" in time. Heretofore, long-duration, 4D motion characterization for radiotherapy planning, margin optimization, and validation have been impractical for safety reasons, requiring invasive markers imaged under x-ray fluoroscopy. To characterize 3D tumor motion and associated variability over durations more consistent with treatments, the authors have developed a practical dynamic MRI (dMRI) technique employing two orthogonal planes acquired in a continuous, interleaved fashion.

Respiration-based sorting of dynamic MRI to derive representative 4D-MRI for radiotherapy planning.

Purpose: Current pretreatment, 4D imaging techniques are suboptimal in that they sample breathing motion over a very limited "snap-shot" in time. To potentially address this, the authors have developed a longer-duration MRI and postprocessing technique to derive the average or most-probable state of mobile anatomy and meanwhile capture and convey the observed motion variability.

Methods: Sagittal and coronal multislice, 2D dynamic MRI was acquired in a sequential fashion over extended durations in two abdominal and four lung studies involving healthy volunteers.

Technical innovation in dynamic contrast-enhanced magnetic resonance imaging of musculoskeletal tumors: an MR angiographic sequence using a sparse k-space sampling strategy.

Objective: We demonstrate the clinical use of an MR angiography sequence performed with sparse k-space sampling (MRA), as a method for dynamic contrast-enhanced (DCE)-MRI, and apply it to the assessment of sarcomas for treatment response.

Materials And Methods: Three subjects with sarcomas (2 with osteosarcoma, 1 with high-grade soft tissue sarcomas) underwent MRI after neoadjuvant therapy/prior to surgery, with conventional MRI (T1-weighted, fluid-sensitive, static post-contrast T1-weighted sequences) and DCE-MRI (MRA, time resolution = 7-10 s, TR/TE 2.4/0.

Augmented reality visualization using image overlay technology for MR-guided interventions: cadaveric bone biopsy at 1.5 T.

Purpose: The purpose of this study was to prospectively test the hypothesis that image overlay technology facilitates accurate navigation for magnetic resonance (MR)-guided osseous biopsy.

Materials And Methods: A prototype augmented reality image overlay system was used in conjunction with a clinical 1.5-T MR imaging system.

MR image overlay guidance: system evaluation for preclinical use.

Purpose: A clinical augmented reality guidance system was developed for MRI-guided musculoskeletal interventions Magnetic Resonance Image Overlay System (MR-IOS). The purpose of this study was to assess MRI compatibility, system accuracy, technical efficacy, and operator performance of the MR-IOS.

Methods And Materials: The impact of the MR-IOS on the MR environment was assessed by measuring image quality with signal-to-noise ratio (SNR) and signal intensity uniformity with the system in various on/off states.

Augmented reality visualization with use of image overlay technology for MR imaging-guided interventions: assessment of performance in cadaveric shoulder and hip arthrography at 1.5 T.

Purpose: To prospectively assess overlay technology in providing accurate and efficient targeting for magnetic resonance (MR) imaging-guided shoulder and hip joint arthrography.

Materials And Methods: A prototype augmented reality image overlay system was used in conjunction with a clinical 1.5-T MR imager.

Augmented reality visualisation using an image overlay system for MR-guided interventions: technical performance of spine injection procedures in human cadavers at 1.5 Tesla.

Objectives: To prospectively assess the technical performance of an augmented reality system for MR-guided spinal injection procedures.

Methods: The augmented reality system was used with a clinical 1.5-T MRI system.

Advanced MR neurography imaging of radial nerve entrapment at the spiral groove: a case report.

High-resolution magnetic resonance neurography (MRN) is being increasingly employed for the evaluation of peripheral nerves. We describe a case of spiral groove syndrome (Saturday night palsy) and illustrate the role of advanced 3 Tesla MRN imaging techniques, including three-dimensional diffusion-weighted fat-suppressed reversed fast imaging with steady-state precession and diffusion tensor imaging.

Augmented reality visualization with image overlay for MRI-guided intervention: accuracy for lumbar spinal procedures with a 1.5-T MRI system.

Objective: The purpose of this study was to prospectively evaluate the accuracy of an augmented reality image overlay system in MRI-guided spinal injection procedures.

Materials And Methods: An augmented reality prototype was used in conjunction with a 1.5-T MRI system.

MR neurography: past, present, and future.

Objective: MR neurography (MRN) has increasingly been used in clinical practice for the evaluation of peripheral nerve disease. This article reviews the historic perspective of MRN, the current imaging trends of this modality, and the future directions and applications that have shown potential for improved imaging and diagnostic capabilities.

Conclusion: MRN has come a long way in the past 2 decades.

The application of three-dimensional diffusion-weighted PSIF technique in peripheral nerve imaging of the distal extremities.

Purpose: To evaluate whether the addition of the three-dimensional diffusion-weighted reversed fast imaging with steady state free precession (3D DW-PSIF) sequence improves the identification of peripheral nerves in the distal extremities.

Materials And Methods: Twelve MR neurography (MRN) studies of the distal upper extremity and 12 MRN studies of distal lower extremity were evaluated. From the 24 subjects who were enrolled, 10 had clinically suspected peripheral neuropathy, whereas 14 suffered from various orthopedic diseases and had no clinical signs of neuropathy.

3T MR neurography using three-dimensional diffusion-weighted PSIF: technical issues and advantages.

Three-dimensional (3D) diffusion-weighted reversed fast imaging with steady state precession (3D DW-PSIF) MR sequence has the potential to create nerve-specific images. The authors describe the technical issues and their initial experience with this imaging technique employed for peripheral MR neurography.