Applications, limitations and advancements of ultra-low-field magnetic resonance imaging: A scoping review.

Background: Ultra-low-field magnetic resonance imaging (ULF-MRI) has emerged as an alternative with several portable clinical applications. This review aims to comprehensively explore its applications, potential limitations, technological advancements, and expert recommendations. Methods: A review of the literature was conducted across medical databases to identify relevant studies. Articles on clinical usage of ULF-MRI were included, and data regarding applications, limitations, and advancements were extracted. A total of 25 articles were included for qualitative analysis. Results: The review reveals ULF-MRI efficacy in intensive care settings and intraoperatively. Technological strides are evident through innovative reconstruction techniques and integration with machine learning approaches. Additional advantages include features such as portability, cost-effectiveness, reduced power requirements, and improved patient comfort. However, alongside these strengths, certain limitations of ULF-MRI were identified, including low signal-to-noise ratio, limited resolution and length of scanning sequences, as well as variety and absence of regulatory-approved contrast-enhanced imaging. Recommendations from experts emphasize optimizing imaging quality, including addressing signal-to-noise ratio (SNR) and resolution, decreasing the length of scan time, and expanding point-of-care magnetic resonance imaging availability. Conclusion: This review summarizes the potential of ULF-MRI. The technology's adaptability in intensive care unit settings and its diverse clinical and surgical applications, while accounting for SNR and resolution limitations, highlight its significance, especially in resource-limited settings. Technological advancements, alongside expert recommendations, pave the way for refining and expanding ULF-MRI's utility. However, adequate training is crucial for widespread utilization.

Predictors of neurocognition outcomes in children and young people with primary brain tumor presenting to tertiary care hospitals of Karachi, Pakistan: a prospective cohort study.

INTRODUCTION: Primary brain tumors are a common cause of morbidity and mortality in children and young people (CYP) globally. Impaired neurocognitive function is a potential severe consequence in primary brain tumor (PBT) survivors. There are no in-depth studies from low- and middle-income countries (LMICs) to inform management and follow-up. The research questions of this study were as follows: Are the sociodemographic factors (lower age of CYP, female gender, low socioeconomic status, low parental education), disease-related factors (high grade of tumor, presence of seizures, presence of hydrocephalous), and treatment-related factors (adjuvant therapy, no surgical intervention, post-treatment seizures, placement of shunts) associated with decline in neurcognition outcomes 12 months post-treatment in CYP with PBTs? METHODS: A prospective cohort study was conducted from November 2020 to July 2023 at the Aga Khan University Hospital and Jinnah Postgraduate Medical Centre, tertiary care hospitals in Karachi, Pakistan. All CYP aged 5 to 21 years with a newly diagnosed PBTs were eligible. The neurocognition assessment was undertaken by a psychologist at two points, i.e., pre-treatment and at 12 months post-treatment using validated tools. The verbal intelligence was assessed by Slosson Intelligence tool, revised 3rd edition (SIT-R3), perceptual reasoning by Raven's Progressive Matrices (RPM), and the Processing Speed Index by Wechsler Intelligence Scale (WISC V) and Wechsler Adult Intelligence Scale (WAIS-IV). The data were analyzed by STATA version 12 software. Generalized estimating equation (GEE) was used to determine the factors associated with the mean change in 12 months post-treatment verbal and non-verbal neurocognition scores. Unadjusted and adjusted beta coefficients with their 95% confidence intervals were reported. RESULTS: A total of 48 CYPs with PBTs were enrolled, 23 (48%) of them were lost to follow-up and 10 (21%) died. The remaining 25 (52%) were reassessed 12 months after treatment. On multivariable analysis, a significant decline in verbal intelligence scores at 12 months was predicted by post-treatment seizures beta = - 20.8 (95% CI, - 38.2, - 3.4), mothers having no formal educational status and lower household monthly income. Similarly, a significant decline in perceptual reasoning scores was also predicted by post-treatment seizures beta = - 10.7 (95% CI, - 20.6, - 0.8), mothers having no formal education and having lower household monthly income. Worsening of processing speed scores at 12 months post-treatment were predicted by tumor histology, post-treatment seizures beta = - 33.9 (95% CI, - 47.7, - 20.0), lower educational status of the mother, and having lower household monthly. However, an improvement was seen in processing speed scores after surgical tumor resection. CONCLUSION: In this novel study, the post-treatment mean change in verbal and non-verbal neurocognition scores was associated with sociodemographic, tumor, and treatment factors. These findings may have potential implications for targeted early psychological screening of higher risk CYP with PBTs. Identification of these predictors may serve as a foundation for developing more cost-effective treatment thereby alleviating the burden of neurocognitive morbidity. However to establish generalizability, future research should prioritize larger-scale, multicountry studies. (Trial registration: ClinicalTrials.gov Identifier: NCT05709522).

Intraoperative use of low-field magnetic resonance imaging for brain tumors: A systematic review.

Background: Low-field magnetic resonance imaging (LF-MRI) has become a valuable tool in the diagnosis of brain tumors due to its high spatial resolution and ability to acquire images in a short amount of time. However, the use of LF-MRI for intraoperative imaging during brain tumor surgeries has not been extensively studied. The aim of this systematic review is to investigate the impact of low-field intraoperative magnetic resonance imaging (LF-IMRI) on the duration of brain tumor surgery and the extent of tumor resection. Methods: A comprehensive literature search was conducted using PubMed, Scopus, and Google Scholar from February 2000 to December 2022. The studies were selected based on the inclusion criteria and reviewed independently by two reviewers. The gathered information was organized and analyzed using Excel. Results: Our review of 21 articles found that low-field intraoperative MRI (LF-IMRI) with a field below 0.3T was used in most of the studies, specifically 15 studies used 0.15T LF-IMRI. The T1-weighted sequence was the most frequently reported, and the average scanning time was 24.26 min. The majority of the studies reported a positive impact of LF-IMRI on the extent of tumor resection, with an increase ranging from 11% to 52.5%. Notably, there were no studies describing the use of ultra-low-field (ULF) intraoperative MRI. Conclusion: The results of this systematic review will aid neurosurgeons and neuroradiologists in making informed decisions about the use of LF-MRI in brain tumor surgeries. Further, research is needed to fully understand the impact of LF-MRI in brain tumor surgeries and to optimize its use in the clinical setting. There is an opportunity to study the utility of ULF-MRI in brain tumor surgeries.

Unveiling the potential application of intraoperative brain smear for brain tumor diagnosis in low-middle-income countries: A comprehensive systematic review.

Background: Immediate intraoperative histopathological examination of tumor tissue is indispensable for a neurosurgeon to track surgical resection. A brain smear is a simple, rapid, and cost-effective technique, particularly important in the diagnosis of brain tumors. The study aims to determine the effectiveness of intraoperative brain smear in the diagnosis of brain tumors in low- and middle-income countries (LMICs), while also evaluating its sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy. Methods: A comprehensive search of the literature was conducted using PubMed, Scopus, and Google Scholar. The retrieved articles were independently screened by two reviewers. The data was extracted, processed, and organized using Microsoft Excel. Results: A total of 59 out of 553 articles screened were included in the final analysis. The sensitivity and specificity of the intraoperative smear of brain tumors were found to be over 90% in most studies. The PPV was consistently above 90% in 11 studies, reaching 100% in one study and the NPV varied, ranging from 63% to 100%, and the accuracy was found to be >80% in most studies. One recurrent theme in the majority of the included studies was that an intraoperative brain smear is a cost-effective, quick, accessible, and accurate method of diagnosing brain tumors, requiring minimal training and infrastructure. Conclusion: Intraoperative brain smear is a simple, rapid, cost-effective, and highly sensitive diagnostic modality for brain tumors. It can be a viable and accessible alternative to more traditional methods such as frozen sections and can be incorporated into neurosurgical practice in LMICs as a reliable and efficient diagnostic tool.

Role of redundant nerve roots in clinical manifestations of lumbar spine stenosis.

BACKGROUND: Redundant nerve roots (RNRs) are defined as elongated, thickened, and tortious appearing roots of the cauda equina secondary to lumbar spinal canal stenosis (LSCS). The study compared the clinical and radiological features of patients with LSCS with versus without RNR. METHODS: This retrospective study was performed on 55 patients who underwent decompressive surgery for degenerative LSCS. Patients were divided into two groups based on the presence of RNR in their preoperative magnetic resonance imaging, as evaluated by a radiologist blinded to the study design. Medical records were reviewed for basic demographic, clinical MR presentation, and outcomes utilizing Japanese Orthopaedic Association (JOA) scores. RESULTS: The mean age of enrolled patients was 57.1, with mean follow-up of 4.0 months. RNR was found in 22 (40%) of patients with LSCS. These patients were older than those patients without RNR (62.2 vs. 53.7). Interestingly, there were no statistically significant differences in clinical presentations, duration of symptoms, and outcomes using JOA scores between the two groups. CONCLUSION: RNR is a relatively common radiological finding (i.e., 40%) in patients with LSCS. It is more likely to be observed in older patients. However, no significant differences were noted in clinical presentation and functional outcomes with respect to the presence or absence of RNR.

Building Bridges through Science.

Science is ideally suited to connect people from different cultures and thereby foster mutual understanding. To promote international life science collaboration, we have launched "The Science Bridge" initiative. Our current project focuses on partnership between Western and Middle Eastern neuroscience communities.

Emergency department predictors of tracheostomy in patients with isolated traumatic brain injury requiring emergency cranial decompression.

OBJECT: Patients with severe traumatic brain injury (TBI) frequently require a tracheostomy for prolonged mechanical ventilation and/or pulmonary toilet. It is now proven that the earlier the procedure is done, the more beneficial it is to the patient. The present study was carried out to determine if the requirement of a tracheostomy can be predicted on arrival of a patient to the emergency department. The prediction can potentially aid in combining the procedure with cranial decompression. In this study, the authors' aim was to determine the emergency department predictors of tracheostomy in patients with isolated TBI requiring emergency cranial decompression. METHODS: The authors performed a retrospective chart review of all patients who underwent surgery for isolated TBI and required more than 4 days of mechanical ventilation. Multivariate logistic regression analysis was used for predictive indicators. RESULTS: In patients with isolated severe TBI, a patient age of 31-50 years, the presence of preexisting medical comorbid conditions, a delay in emergency department arrival exceeding 1.5 hours, an abnormal pupil response on arrival, and a preoperative neurological worsening during hospital stay were independent predictors of the requirement for tracheostomy. These findings were validated in a small cohort of patients and were found to be significant. CONCLUSIONS: Requirement of a tracheostomy can be predicted in patients with severe TBI on arrival to the emergency department. These results were validated in a small cohort of patients, and it was found that the positive predictive value of requirement of tracheostomy was directly proportional to the number of predictors present. Larger prospective studies with appropriate control groups are further recommended to validate the authors' findings.

Management of an extensive spinal epidural abscess from C-1 to the sacrum. Case report.

The authors report a rare case of extensive spinal epidural abscess in an immunocompromised young woman. The patient presented with low-grade fever, back pain, and progressive lower limb weakness. The MR imaging of her whole spine revealed an epidural abscess extending from C-1 to the sacrum. She was treated using a minimally invasive surgical technique and showed excellent recovery. The authors review the current literature along with different modes of surgical treatment available for this unusual clinical entity.

Stem cells for spinal cord regeneration: Current status.

BACKGROUND: Nearly 11,000 cases of spinal cord injury (SCI) are reported in the United States annually. Current management options give a median survival time of 38 years; however, no rehabilitative measures are available. Stem cells have been under constant research given their ability to differentiate into neural cell lines replacing non functional tissue. Efforts have been made to establish new synapses and provide a conducive environment, by grafting cells from autologous and fetal sources; including embryonic or adult stem cells, Schwann cells, genetically modified fibroblasts, bone stromal cells, and olfactory ensheathing cells and combinations/ variants thereof. METHODS: In order to discuss the underlying mechanism of SCI along with the previously mentioned sources of stem cells in context to SCI, a simple review of literature was conducted. An extensive literature search was conducted using the PubMed data base and online search engines and articles published in the last 15 years were considered along with some historical articles where a background was required. RESULTS: Stem cell transplantation for SCI is at the forefront with animal and in vitro studies providing a solid platform to enable well-designed human studies. Olfactory ensheathing cells seem to be the most promising; whilst bone marrow stromal cells appear as strong candidates for an adjunctive role. CONCLUSION: The key strategy in developing the therapeutic basis of stem cell transplantation for spinal cord regeneration is to weed out the pseudo-science and opportunism. All the trials should be based on stringent scientific criteria and effort to bypass that should be strongly discouraged at the international level.

Orbital aspergillus infection mimicking a tumour: a case report.

A 14-year-old male presented to the neurosurgical clinic with swelling just above the right eye which had been growing slowly for the last eight years. The swelling first appeared following a non-penetrating trauma eight years ago. On examination it was a non-tender, non-erythematous, firm, round swelling causing marked proptosis and diplopia on downward gaze only. The visual acuity was intact. MRI showed an intraorbital, extraconal mass isointense on T1 and hypointense on T2 imaging. A diagnosis of orbital tumor was made. A white, friable mass consistent with meningioma was resected. However histopathology report later showed it to be an Aspergilloma. The patient was successfully treated with anti-fungal medicine and was disease-free at one year follow-up.

Experiences from an international tele-epilepsy collaboration.

OBJECTIVE: Our main objective was to use videoconferencing as a primary means to: a) assist in launching an epilepsy surgery program in Pakistan; 2) participate in case conferences on complex epilepsy patients in each country. METHODS: Extensive testing using both point to point and bridged integrated service digital network (ISDN) and internet protocol (IP) connections was carried out using bandwidths of 384-768 kilobits per second (kbps). Videoconferences between sites were arranged two to three weeks in advance and connections were tested a day prior to the scheduled conference. Sharing of PowerPoint presentations, neuroimaging and video-EEG was available to all sites. Discussions centered on patients with medically refractory epilepsy. RESULTS: Between July 2006 and June 2008, 17 sessions were booked. Five of these conferences bridged in specialists from West Virginia University. Most successful connections occurred using IP point to point calls or a bridge connecting end points through IP at 512 kbps. We conducted three surgeries for medically refractory temporal lobe epilepsy in Pakistan. At follow-up in January 2009, two patients have been seizure free and one had two breakthrough seizures after sudden unsupervised discontinuation of Levetiracetam. CONCLUSION: Our international tele-epilepsy collaboration has proven feasible and valuable to all participants. Our experience suggests considerable thought and preparation are needed before a teleconference to ensure its success. We provide a recipe to set-up similar telemedicine collaborations. Considerations include time zone differences, equipment type, interoperability between endpoints, connection capabilities, bandwidth availability, and backup plans for unsuccessful connections. Telemedicine can facilitate epilepsy care around the world, identifying with the concept of a "Global Health Village".

Cost-effectiveness of clipping vs coiling of intracranial aneurysms after subarachnoid hemorrhage in a developing country--a prospective study.

BACKGROUND: Endovascular coil treatment is being used increasingly as an alternative to clipping for some ruptured intracranial aneurysms. The relative benefits of these 2 approaches have yet to be fully established. The aim of this study was to compare the clinical outcome, resource consumption, and cost-effectiveness of endovascular treatment vs surgical clipping in a developing country. METHODS: The study population consisted of 55 patients with aneurysmal subarachnoid hemorrhage (SAH) identified prospectively from January 2004 to June 2007. Of the 55 patients with ruptured intracranial aneurysms, 31 underwent surgical clipping, whereas 24 were treated via interventional coils. Clinical outcome at 6 months, using the modified Rankin Scale, and cost of treatment related to all aspects of the inpatient stay were evaluated in both groups. RESULTS: The average age of the patients in the endovascular group was 38 years, whereas in the surgical group, it was 45 years. Most patients (43) were found to be in grades (1 and 2). Of these patients, 18 received coils and 25 were clipped. The remaining 12 patients were of poor grades (3 and 4), of which 6 had coiling and 6 underwent clipping. Most the patients (46/55) had anterior circulation aneurysms, and the rest of the patients (9/55) had posterior circulation aneurysms. The clinical outcome was similar in comparison (good in 81% for clipping and 83% for coiling). The average total cost for patients undergoing endovascular treatment of the aneurysms was $5080, whereas the average total cost of surgical clipping was $3127. CONCLUSION: Patients with aneurysmal SAH whom we judged to require coiling had higher charges than patients who could be treated by clipping. The benefits of apparent decrease in length of stay in the endovascular group were offset by higher procedure price and cost of consumables. There was no significant difference in clinical outcome at 6 months. We have proposed a risk scoring system to give guidelines regarding the choice of treatment considering size of aneurysm and resource allocation.

Ancient schwannoma presenting as a thoracic mass.

BACKGROUND: Ancient schwannoma is a rare variant of schwannoma, histologically showing atypical features that may result in erroneous diagnosis of a malignant tumor. There are only few reported cases in literature. CASE DESCRIPTION: We report a case of a 34-year-old man who was found to have giant mediastinal tumor. He underwent thoracotomy to remove the mass, which was proven to be ancient schwannoma on histopathology. CONCLUSIONS: Clinical and radiological findings are important aids for further consideration of surgical removal of these potentially respectable tumors with good outcome.

Diagnostic MR imaging features of craniocerebral Aspergillosis of sino-nasal origin in immunocompetent patients.

BACKGROUND: Craniocerebral invasive Aspergillosis of sino-nasal origin has been reported with a very high mortality due to a peculiarly fulminant clinical course. Early diagnosis based on clinical radiological imaging may have an impact on final clinical outcome. This retrospective study focuses on characteristic MR imaging features of Aspergillosis (of sinonasal origin) in immunocompetent patients. METHODS: Medical records of patients were reviewed retrospectively during the period from 1991 to 2003 in the two tertiary care hospitals. All the patients had radiological evidence of disease in the paranasal sinuses with or without intracranial extension. Immunocompetence of patients was assessed on clinical and radiological data. MRI scans (n=20) were reviewed by both clinical neurosurgeons and neuroradiologists separately. MRI was done on 1.5 tesla scanners and both T2-weighted and T1 weighted sequences were obtained followed gadolinium enhanced images. Patients were categorized into three types based on their anatomical location on MRI scans; type-1 being intracerebral, type-2 as intracranial extradural and type-3 invading orbit and/or skull base only. All these patient had the epicenter of disease in the nose and/or paranasal sinuses as evident on MR imaging. All patients underwent standard surgical intervention followed by antifungal therapy. Clinical outcome was assessed on Glasgow outcome scale with mean duration of clinical follow up of 13.9 months. FINDINGS: Mean age of patents (n=20) was 31.1 years with male preponderance (3:1). MRI scans showed evidence of disease in paranasal sinuses including mucosal thickening (n=11) and complete filling of sinuses (n=9). T2-weighted images showed extremely hypo-intense fungal mass (n=19) while T1-weighted images had iso-intense signals (n=18). Gadolinium-enhanced images showed bright homogenous contrast enhancement (n=18) and peripheral ring enhancement pattern (n=2). All patients underwent appropriated surgical procedures depending upon anatomical location followed by standard antifungal therapy. Tissue diagnoses were established by histopathology (n=20) and culture growth (n=5). Overall mortality remained 15 percent. INTERPRETATION: Craniocerebral Aspergillosis of sinonasal origin has typical MR imaging features. These features include a mass lesion producing hypo-to-iso-intense signals on T1-weighted, extremely low signals (hypo-intense) on T2-weighted images, with bright homogenous enhancement on post-gadolinium T1-weighted imaging. These features in the clinical background may be helpful in early diagnosis and management of Aspergillosis of sino-nasal origin in immunocompetent hosts. Prospective clinical study is required to make firm clinical therapeutic recommendations.