MR-guided spine interventions: time to get off the ground?
Ontology highlight
ABSTRACT:
SUBMITTER: Splendiani A
PROVIDER: S-EPMC8640907 | biostudies-literature | 2021 Nov
REPOSITORIES: biostudies-literature
Publications
MR-guided spine interventions: time to get off the ground?
Splendiani Alessandra A Bruno Federico F
Annals of translational medicine 20211101 21
Similar Datasets
Project description:Interventional MR uses rapid imaging to guide diagnostic and therapeutic procedures. One of the attractions of MR-guidance is the abundance of inherent contrast mechanisms available. Dynamic procedural guidance with real-time imaging has pushed the limits of MR technology, demanding rapid acquisition and reconstruction paired with interactive control and device visualization. This article reviews the technical aspects of real-time MR sequences that enable MR-guided interventions.
| S-EPMC4621782 | biostudies-literature
Project description:Intraoperative localization of target anatomy and critical structures defined in preoperative MR/CT images can be achieved through the use of multimodality deformable registration. We propose a symmetric diffeomorphic deformable registration algorithm incorporating a modality-independent neighborhood descriptor (MIND) and a robust Huber metric for MR-to-CT registration. The method, called MIND Demons, finds a deformation field between two images by optimizing an energy functional that incorporates both the forward and inverse deformations, smoothness on the integrated velocity fields, a modality-insensitive similarity function suitable to multimodality images, and smoothness on the diffeomorphisms themselves. Direct optimization without relying on the exponential map and stationary velocity field approximation used in conventional diffeomorphic Demons is carried out using a Gauss-Newton method for fast convergence. Registration performance and sensitivity to registration parameters were analyzed in simulation, phantom experiments, and clinical studies emulating application in image-guided spine surgery, and results were compared to mutual information (MI) free-form deformation (FFD), local MI (LMI) FFD, normalized MI (NMI) Demons, and MIND with a diffusion-based registration method (MIND-elastic). The method yielded sub-voxel invertibility (0.008 mm) and nonzero-positive Jacobian determinants. It also showed improved registration accuracy in comparison to the reference methods, with mean target registration error (TRE) of 1.7 mm compared to 11.3, 3.1, 5.6, and 2.4 mm for MI FFD, LMI FFD, NMI Demons, and MIND-elastic methods, respectively. Validation in clinical studies demonstrated realistic deformations with sub-voxel TRE in cases of cervical, thoracic, and lumbar spine.
| S-EPMC5097014 | biostudies-literature
Project description:Background and purposeTranscranial MR imaging-guided focused ultrasound is a promising novel technique to treat multiple disorders and diseases. Planning for transcranial MR imaging-guided focused ultrasound requires both a CT scan for skull density estimation and treatment-planning simulation and an MR imaging for target identification. It is desirable to simplify the clinical workflow of transcranial MR imaging-guided focused ultrasound treatment planning. The purpose of this study was to examine the feasibility of deep learning techniques to convert MR imaging ultrashort TE images directly to synthetic CT of the skull images for use in transcranial MR imaging-guided focused ultrasound treatment planning.Materials and methodsThe U-Net neural network was trained and tested on data obtained from 41 subjects (mean age, 66.4 ± 11.0 years; 15 women). The derived neural network model was evaluated using a k-fold cross-validation method. Derived acoustic properties were verified by comparing the whole skull-density ratio from deep learning synthesized CT of the skull with the reference CT of the skull. In addition, acoustic and temperature simulations were performed using the deep learning CT to predict the target temperature rise during transcranial MR imaging-guided focused ultrasound.ResultsThe derived deep learning model generates synthetic CT of the skull images that are highly comparable with the true CT of the skull images. Their intensities in Hounsfield units have a spatial correlation coefficient of 0.80 ± 0.08, a mean absolute error of 104.57 ± 21.33 HU, and a subject-wise correlation coefficient of 0.91. Furthermore, deep learning CT of the skull is reliable in the skull-density ratio estimation (r = 0.96). A simulation study showed that both the peak target temperatures and temperature distribution from deep learning CT are comparable with those of the reference CT.ConclusionsThe deep learning method can be used to simplify workflow associated with transcranial MR imaging-guided focused ultrasound.
| S-EPMC7661089 | biostudies-literature
Project description:PurposeTo develop an effective and practical reconstruction pipeline to achieve motion-robust, multi-slice, real-time MR thermometry for monitoring thermal therapy in abdominal organs.MethodsThe application includes a fast spiral magnetic resonance imaging (MRI) pulse sequence and a real-time reconstruction pipeline based on multi-baseline proton resonance frequency shift (PRFS) method with visualization of temperature imaging. The pipeline supports multi-slice acquisition with minimal reconstruction lag. Simulations with a virtual motion phantom were performed to investigate the influence of the number of baselines and respiratory rate on the accuracy of temperature measurement. Phantom experiments with ultrasound heating were performed using a custom-made motion phantom to evaluate the performance of the pipeline. Lastly, experiments in healthy volunteers (N = 2) without heating were performed to evaluate the accuracy and stability of MR thermometry in abdominal organs (liver and kidney).ResultsThe multi-baseline approach with greater than 25 baselines resulted in minimal temperature errors in the simulation. Phantom experiments demonstrated a 713 ms update time for 3-slice acquisitions. Temperature maps with 30 baselines showed clear temperature distributions caused by ultrasound heating in the respiratory phantom. Finally, the pipeline was evaluated with physiologic motions in healthy volunteers without heating, which demonstrated the accuracy (root mean square error [RMSE]) of 1.23 ± 0.18 °C (liver) and 1.21 ± 0.17 °C (kidney) and precision of 1.13 ± 0.11 °C (liver) and 1.16 ± 0.15 °C (kidney) using 32 baselines.ConclusionsThe proposed real-time acquisition and reconstruction pipeline allows motion-robust, multi-slice, real-time temperature monitoring within the abdomen during free breathing.
| S-EPMC10269483 | biostudies-literature
Project description:PurposeThe authors performed this study to report their initial preclinical experience with real-time magnetic resonance (MR) imaging-guided atrial septal puncture by using a MR imaging-conspicuous blunt laser catheter that perforates only when energized.Materials and methodsThe authors customized a 0.9-mm clinical excimer laser catheter with a receiver coil to impart MR imaging visibility at 1.5 T. Seven swine underwent laser transseptal puncture under real-time MR imaging. MR imaging signal-to-noise ratio profiles of the device were obtained in vitro. Tissue traversal force was tested with a calibrated meter. Position was corroborated with pressure measurements, oximetry, angiography, and necropsy. Intentional non-target perforation simulated serious complication.ResultsEmbedded MR imaging antennae accurately reflected the position of the laser catheter tip and profile in vitro and in vivo. Despite having an increased profile from the microcoil, the 0.9-mm laser catheter traversed in vitro targets with similar force (0.22 N +/- 0.03) compared with the unmodified laser. Laser puncture of the atrial septum was successful and accurate in all animals. The laser was activated an average of 3.8 seconds +/- 0.4 before traversal. There were no sequelae after 6 hours of observation. Necropsy revealed 0.9-mm holes in the fossa ovalis in all animals. Intentional perforation of the aorta and atrial free wall was evident immediately.ConclusionsMR imaging-guided laser puncture of the interatrial septum is feasible in swine and offers controlled delivery of perforation energy by using an otherwise blunt catheter. Instantaneous soft tissue imaging provides immediate feedback on safety.
| S-EPMC2587284 | biostudies-literature
Project description:The aim of this study was the development and evaluation of a real-time guidance support using optical Moiré Phase Tracking (MPT) for magnetic resonance (MR) guided percutaneous interventions. A gradient echo sequence, capable of real-time position updates by the MPT system, was modified to enable needle guidance based on four rigidly attached MPT markers at the back of a needle. Two perpendicular imaging planes were automatically aligned along the calibrated needle and centered at its tip. For user guidance, additional information about the needle trajectory and the tip to target distance were added as image overlay. Both, images and guiding information were displayed on the in-room monitor to facilitate MR guided interventions. The guidance support was evaluated by four experienced interventional radiologists and four novices targeting rubber O-rings embedded in a custom-made phantom on a 3T wide-bore MRI system (80 punctures). The skin to target time, user error, system error and total error were analyzed. The mean skin to target time was 146s±68s with no statistically significant difference between experts and novices. A low mean user error (0.91mm±0.43mm), system error (0.53mm±0.27mm) and total error (0.99mm±0.47mm) was reached in all directions. No statistically significant difference in user error, system error and total error could be found between experts and novices. The presented tracking and image guidance system combined with the user interface offers continuous and interactive control of the imaging plane while puncturing in the magnet enabling accurate real-time feedback for both, experienced and non-experienced users.
| S-EPMC6191114 | biostudies-literature
Project description:The purpose of the present study was to integrate an interactive gradient-based needle navigation system and to evaluate the feasibility and accuracy of the system for real-time MR guided needle puncture in a multi-ring phantom and in vivo in a porcine model. The gradient-based navigation system was implemented in a 1.5T MRI. An interactive multi-slice real-time sequence was modified to provide the excitation gradients used by two sets of three orthogonal pick-up coils integrated into a needle holder. Position and orientation of the needle holder were determined and the trajectory was superimposed on pre-acquired MR images. A gel phantom with embedded ring targets was used to evaluate accuracy using 3D distance from needle tip to target. Six punctures were performed in animals to evaluate feasibility, time, overall error (target to needle tip) and system error (needle tip to the guidance needle trajectory) in vivo. In the phantom experiments, the overall error was 6.2±2.9 mm (mean±SD) and 4.4±1.3 mm, respectively. In the porcine model, the setup time ranged from 176 to 204 seconds, the average needle insertion time was 96.3±40.5 seconds (min: 42 seconds; max: 154 seconds). The overall error and the system error was 8.8±7.8 mm (min: 0.8 mm; max: 20.0 mm) and 3.3±1.4 mm (min: 1.8 mm; max: 5.2 mm), respectively.
| S-EPMC7380643 | biostudies-literature
Project description:Functional magnetic resonance imaging allows precise localization of brain regions specialized for different perceptual and higher cognitive functions. However, targeting these deep brain structures for electrophysiology still remains a challenging task. Here, we propose a novel framework for MRI-stereotactic registration and chamber placement for precise electrode guidance to recording sites defined in MRI space. The proposed "floating frame" approach can be used without usage of ear bars, greatly reducing pain and discomfort common in standard stereotactic surgeries. Custom pre-surgery planning software was developed to automatically solve the registration problem and report the set of parameters needed to position a stereotactic manipulator to reach a recording site along arbitrary, non-vertical trajectories. Furthermore, the software can automatically identify blood vessels and assist in finding safe trajectories to targets. Our approach was validated by targeting different regions in macaque monkeys and rats. We expect that our method will facilitate recording in new brain areas and provide a valuable tool for electrophysiologists.
| S-EPMC8204678 | biostudies-literature
Project description:PurposeTo characterize the inter- and intraobserver variability of qualitative, non-disk contour degenerative findings of the lumbar spine at magnetic resonance (MR) imaging.Materials and methodsThe case accrual method used to perform this institutional review board-approved, HIPAA-compliant retrospective study was the random selection of 111 interpretable MR examination cases of subjects from the Spine Patient Outcomes Research Trial. The subjects were aged 18-87 years (mean, 53 years +/- 16 [standard deviation]). Four independent readers rated the cases according to defined criteria. A subsample of 40 MR examination cases was selected for reevaluation at least 1 month later. The following findings were assessed: spondylolisthesis, disk degeneration, marrow endplate abnormality (Modic changes), posterior anular hyperintense zone (HIZ), and facet arthropathy. Inter- and intraobserver agreement in rating the data was summarized by using weighted kappa statistics.ResultsInterobserver agreement was good (kappa = 0.66) in rating disk degeneration and moderate in rating spondylolisthesis (kappa = 0.55), Modic changes (kappa = 0.59), facet arthropathy (kappa = 0.54), and posterior HIZ (kappa = 0.44). Interobserver agreement in rating the extent of Modic changes was moderate: kappa Values were 0.43 for determining superior anteroposterior extent, 0.47 for determining superior craniocaudal extent, 0.57 for determining inferior anteroposterior extent, and 0.48 for determining inferior craniocaudal extent. Intraobserver agreement was good in rating spondylolisthesis (kappa = 0.66), disk degeneration (kappa = 0.74), Modic changes (kappa = 0.64), facet arthropathy (kappa = 0.69), and posterior HIZ (kappa = 0.67). Intraobserver agreement in rating the extent of Modic changes was moderate, with kappa values of 0.54 for superior anteroposterior, 0.60 for inferior anteroposterior, 0.50 for superior craniocaudal, and 0.60 for inferior craniocaudal extent determinations.ConclusionThe interpretation of general lumbar spine MR characteristics has sufficient reliability to warrant the further evaluation of these features as potential prognostic indicators.
| S-EPMC2657480 | biostudies-literature
Project description:Notochord sheath cells were FACS isolated from 13 days post fertilization (dpf) transgenic zebrafish. Three biological replicates were used for each population, and expression profiles were determined using Illumina HiSeq. Comparison of the sample groups allowed for identification of unique candidates. The sequence reads that passed quality filters were analyzed using HISAT2, and gene counts were analyzed using HTSeq.
2018-02-20 | GSE109176 | GEO