Optimizing Filter-Probe Diffusion Weighting in the Rat Spinal Cord for Human Translation

Diffusion tensor imaging (DTI) is a promising biomarker of spinal cord injury (SCI). In the acute aftermath, DTI in SCI animal models consistently demonstrates high sensitivity and prognostic performance, yet translation of DTI to acute human SCI has been limited. In addition to technical challenges, interpretation of the resulting metrics is ambiguous, with contributions in the acute setting from both axonal injury and edema. Novel diffusion MRI acquisition strategies such as double diffusion encoding (DDE) have recently enabled detection of features not available with DTI or similar methods. In this work, we perform a systematic optimization of DDE using simulations and an in vivo rat model of SCI and subsequently implement the protocol to the healthy human spinal cord. First, two complementary DDE approaches were evaluated using an orientationally invariant or a filter-probe diffusion encoding approach. While the two methods were similar in their ability to detect acute SCI, the filter-probe DDE approach had greater predictive power for functional outcomes. Next, the filter-probe DDE was compared to an analogous single diffusion encoding (SDE) approach, with the results indicating that in the spinal cord, SDE provides similar contrast with improved signal to noise. In the SCI rat model, the filter-probe SDE scheme was coupled with a reduced field of view (rFOV) excitation, and the results demonstrate high quality maps of the spinal cord without contamination from edema and cerebrospinal fluid, thereby providing high sensitivity to injury severity. The optimized protocol was demonstrated in the healthy human spinal cord using the commercially-available diffusion MRI sequence with modifications only to the diffusion encoding directions. Maps of axial diffusivity devoid of CSF partial volume effects were obtained in a clinically feasible imaging time with a straightforward analysis and variability comparable to axial diffusivity derived from DTI. Overall, the results and optimizations describe a protocol that mitigates several difficulties with DTI of the spinal cord. Detection of acute axonal damage in the injured or diseased spinal cord will benefit the optimized filter-probe diffusion MRI protocol outlined here

Utility of intraoperative neurophysiological monitering (ionm) in various surgeries at a tertery care hospital in karachi, pakistan.

Utility of real time multimodal intraoperative neurophysiological monitoring in different intracranial, spinal and peripheral nerve at a tertiary care hospital in Karachi Pakistan.Study design: A retrospective observational study Place and duration of study: Patients admitted in neurology and neurosurgery services as well as out-patients presenting to the clinical neurophysiology lab at the Aga Khan University Hospital Karachi between January 2012 to December 2013.Methodology: The study consisted of 14 patients undergoing different intracranial, spinal and peripheral nerve surgeries including correction of spinal scoliosis, spinal cord lesion ,acoustic neuroma resection and plexus and peripheral nerve repaired. Among the electrophysiological methods patients were monitored using including SSEP, BAEP and EMG (free-running and triggered). EMG was done on Nihon Kohden Viking Quest from Nicolet Co. For SSEPs GillioNT from EB Neuro Co, and for NIOM carefusion from Nicolet Co was used.Results: Mean age of patients was 39 years (4-70 years). SSEP, BAEP and EMG (free-running and triggered) were recorded, during various surgeries. Of total 14 patients, no patient expressed a significant alert to prompt reversal of ongoing intervention. No patients awoke with a new neurological deficit and none had significant intraoperative SSEP /EMG alerts. Conclusion: Neurophysiologic intraoperative monitoring appears to be the modern standard of care for monitoring functional integrity and minimizing the risk of iatrogenic damage to the central and peripheral nervous system

Combining brain-computer interfaces and assistive technologies: state-of-the-art and challenges

In recent years, new research has brought the field of EEG-based Brain-Computer Interfacing (BCI) out of its infancy and into a phase of relative maturity through many demonstrated prototypes such as brain-controlled wheelchairs, keyboards, and computer games. With this proof-of-concept phase in the past, the time is now ripe to focus on the development of practical BCI technologies that can be brought out of the lab and into real-world applications. In particular, we focus on the prospect of improving the lives of countless disabled individuals through a combination of BCI technology with existing assistive technologies (AT). In pursuit of more practical BCIs for use outside of the lab, in this paper, we identify four application areas where disabled individuals could greatly benefit from advancements in BCI technology, namely,“Communication and Control”, “Motor Substitution”, “Entertainment”, and “Motor Recovery”. We review the current state of the art and possible future developments, while discussing the main research issues in these four areas. In particular, we expect the most progress in the development of technologies such as hybrid BCI architectures, user-machine adaptation algorithms, the exploitation of users’ mental states for BCI reliability and confidence measures, the incorporation of principles in human-computer interaction (HCI) to improve BCI usability, and the development of novel BCI technology including better EEG devices

Automatic Spinal Cord Segmentation From Medical MR Images using Hybrid Algorithms

Medical image processing is the top most research area. There are huge amount of researches found in the medical image analyze, classification and segmentation process. Spinal cord segmentation of MRI images is the challenging process. In the proposed research work, automatic Spinal Cord (SC) segmentation from medical MRI image is performed with various techniques. The proposed work improves the segmentation with less iteration and improved accuracy by adopting improved Weighted Expectation Maximization (WEM) and Strong Fitness Firefly (SFF) algorithms. The proposed work effectively segments the spinal cord by applying effective pre-processing, image enhancement process and clustering with less iterations. Using the combination of different techniques, the proposed system effectively identifies the spinal cord from the MRI image, the experiments performed using Matlab tool. The accuracy is calculated and shown for the proposed system. The result shows, the mixed approach of WEM and SFF increases the segmentation accuracy than using the WEM alone

Traumatic spinal cord injury; Theranostic applications of advanced MRI techniques

Imaging technology is an important part of the diagnosis and management of spinal trauma. However, many efforts have been made to develop new diagnostic biomarkers through advanced imaging techniques. Unfortunately, there is still no consensus for practical use of biomarkers in SCI patients. The authors conducted an all-encompassing literature review and relevant images were included as examples. Spinal cord and soft-tissue injuries are best evaluated by magnetic resonance imaging (MRI). However, advanced MRI techniques provide researchers with a noninvasive approach that allows evaluation of physiological and biochemical condition of the spinal cord and the brain at cellular and molecular level. The advent of new rehabilitation and treatment strategies could demand more precise and advanced techniques to approach the pathophysiology and anatomy of the spinal cord, offering more accurate and non-invasive support to research and clinical follow up

Neurological signs and MRI findings in 12 dogs with multiple myeloma

Vertebral lesions and associated neurological signs occur in dogs with multiple myeloma, however, veterinary literature describing MRI findings is currently lacking. The objective of this multicenter, retrospective, case series study was to describe neurological signs and MRI findings in a group of dogs that presented for spinal pain or other neurological deficits and had multiple myeloma. Electronic records of four veterinary referral hospitals were reviewed. Dogs were included if they had a pathologically confirmed diagnosis of multiple myeloma, had presented for spinal pain or other neurological signs, and had undergone MRI of the vertebral column. The MRI studies were evaluated and the anatomical location of lesion(s), signal intensity, presence of extra‐dural material, degree of spinal cord compression, extent of vertebral lesions, and contrast enhancement were recorded. Twelve dogs met inclusion criteria. Most dogs (n = 8) had a chronic progressive history, with varying degrees of proprioceptive ataxia and paresis (n = 11), and spinal pain was a feature in all dogs. The MRI findings were variable but more consistent features included the presence of multiple expansile vertebral lesions without extension beyond the outer cortical limits of affected vertebrae, and associated extradural material causing spinal cord compression. The majority of lesions were hyper‐ to isointense on T2 (n = 12) and T1‐weighted (n = 8) sequences, with variable but homogeneous contrast‐enhancement (n = 12). These described MRI characteristics of multiple myeloma may be used to aid early identification and guide subsequent confirmatory diagnostic steps, to ultimately improve therapeutic approach and long‐term outcome

Transcranial magnetic stimulation as a new tool to control pain perception.

Treatment for chronic pain is frequently unsuccessful or characterized by side-effects. The high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) has been suggested in the management of refractory chronic pain. Various studies have shown that HF-rTMS sessions of long-duration applied at primary motor cortex induce pain relief through mechanisms of plastic changes. Efficacy of rTMS mostly depends on stimulation parameters, but this aspect requires better characterization. A rationale to target other cortical areas exists. Current data are promising, but a careful analysis of stimulation settings and maintenance treatment design are need

Serial Ultrasonography for Early Detection and Follow-up of Heterotopic Ossification in Stroke

Heterotopic ossification (HO) is a common complication in patients with neurologic deficits. Once developed, limited range of motion may occur and interfere with rehabilitation programs. Early diagnosis is crucial but difficult because radiographs may be negative, and similar clinical symptoms could appear in deep venous thrombosis, cellulitis, and osteomyelitis. A three-phase bone scan can detect the disease early, but it has high radiation and low specificity. Magnetic resonance imaging (MRI) may also assist in diagnosis, but is costly and has some contraindications. Ultrasonography has been used in HO detection and is safe, economical, easily accessible, and involves no radiation exposure. However, a few studies have described its use in HO, especially in serial follow-ups. We report a case with HO clinical symptoms, but the MRI results created a necrotizing fasciitis suspicion. Serial ultrasonography images implied the formation of HO rather than necrotizing fasciitis. Ultrasonography images serve as a good initial screening tool for HO and are useful for following up such dynamic disease processes

Diseases of the Brain, Head and Neck, Spine 2020–2023

This open access book offers an essential overview of brain, head and neck, and spine imaging. Over the last few years, there have been considerable advances in this area, driven by both clinical and technological developments. Written by leading international experts and teachers, the chapters are disease-oriented and cover all relevant imaging modalities, with a focus on magnetic resonance imaging and computed tomography. The book also includes a synopsis of pediatric imaging. IDKD books are rewritten (not merely updated) every four years, which means they offer a comprehensive review of the state-of-the-art in imaging. The book is clearly structured and features learning objectives, abstracts, subheadings, tables and take-home points, supported by design elements to help readers navigate the text. It will particularly appeal to general radiologists, radiology residents, and interventional radiologists who want to update their diagnostic expertise, as well as clinicians from other specialties who are interested in imaging for their patient care