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Neurosurgical Review Jun 2022Elevated intracranial pressure (ICP) with reduced cerebral perfusion pressure is a well-known cause of secondary brain injury. Previously, there have been some reports... (Meta-Analysis)
Meta-Analysis Review
Elevated intracranial pressure (ICP) with reduced cerebral perfusion pressure is a well-known cause of secondary brain injury. Previously, there have been some reports describing different supra- and infratentorial ICP measurements depending on the location of the mass effect. Therefore, we aimed to perform a systematic review and meta-analysis to clarify the issue of optimal ICP monitoring in the infratentorial mass lesion. A literature search of electronic databases (PUBMED, EMBASE) was performed from January 1969 until February 2021 according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement. Two assessors are independently screened for eligible studies reporting the use of simultaneous ICP monitoring in the supra- and infratentorial compartments. For quality assessment of those studies, the New Castle Ottawa Scale was used. The primary outcome was to evaluate the value of supra- and infratentorial ICP measurement, and the secondary outcome was to determine the time threshold until equalization of both values. Current evidence surrounding infratentorial ICP measurement was found to be low to very low quality according to New Castle Ottawa Scale. Eight studies were included in the systematic review, four of them containing human subjects encompassing 27 patients with infratentorial pathology. The pooled data demonstrated significantly higher infratentorial ICP values than supratentorial ICP values 12 h after onset (p < 0.05, 95% CI 3.82-5.38) up to 24 h after onset (p < 0.05; CI 1.14-3.98). After 48-72 h, both ICP measurements equilibrated showing no significant difference. Further, four studies containing 26 pigs and eight dogs showed a simultaneous increase of supra- and infratentorial ICP value according to the increase of supratentorial mass volume; however, there was a significant difference towards lower ICP in the infratentorial compartment compared to the supratentorial compartment. The transtentorial gradient leads to a significant discrepancy between supra- and infratentorial ICP monitoring. Therefore, infratentorial ICP monitoring is warranted in case of posterior fossa lesions for at least 48 h.
Topics: Animals; Cerebrovascular Circulation; Dogs; Humans; Intracranial Hypertension; Intracranial Pressure; Monitoring, Physiologic; Skull; Swine
PubMed: 35118578
DOI: 10.1007/s10143-022-01746-y -
Child's Nervous System : ChNS :... Sep 2021Paediatric postoperative cerebellar mutism syndrome (ppCMS) is a common complication following the resection of a cerebellar tumour in children. It is hypothesized that... (Review)
Review
BACKGROUND
Paediatric postoperative cerebellar mutism syndrome (ppCMS) is a common complication following the resection of a cerebellar tumour in children. It is hypothesized that loss of integrity of the cerebellar output tracts results in a cerebello-cerebral "diaschisis" and reduced function of supratentorial areas of the brain.
METHODS
We performed a systematic review of the literature according to the PRISMA guidelines, in order to evaluate the evidence for hypoperfusion or hypofunction in the cerebral hemispheres in patients with ppCMS. Articles were selected based on the predefined eligibility criteria and quality assessment.
RESULTS
Five studies were included, consisting of three prospective cohort studies, one retrospective cohort study and one retrospective case control study. Arterial spin labelling (ASL) perfusion MRI, dynamic susceptibility contrast (DSC) perfusion MRI and single photon emission computed tomography (SPECT) were used to measure the cerebral and cerebellar tissue perfusion or metabolic activity. Reduced cerebral perfusion was predominantly demonstrated in the frontal lobe.
CONCLUSIONS
This systematic review shows that, after posterior fossa tumour resection, cerebral perfusion is reduced in ppCMS patients compared to patients without ppCMS. Well-powered prospective studies, including preoperative imaging, are needed to ascertain the cause and role of hypoperfusion in the pathophysiology of the syndrome.
Topics: Case-Control Studies; Cerebellar Diseases; Cerebellum; Cerebrovascular Circulation; Child; Humans; Mutism; Perfusion; Postoperative Complications; Prospective Studies; Retrospective Studies
PubMed: 34155533
DOI: 10.1007/s00381-021-05225-5 -
Biomedicines Jan 2022Glioblastoma is the most frequent malignant primitive brain tumor in adults. The treatment includes surgery, radiotherapy, and chemotherapy. During follow-up, combined... (Review)
Review
BACKGROUND
Glioblastoma is the most frequent malignant primitive brain tumor in adults. The treatment includes surgery, radiotherapy, and chemotherapy. During follow-up, combined chemoradiotherapy can induce treatment-related changes mimicking tumor progression on medical imaging, such as pseudoprogression (PsP). Differentiating PsP from true progression (TP) remains a challenge for radiologists and oncologists, who need to promptly start a second-line treatment in the case of TP. Advanced magnetic resonance imaging (MRI) techniques such as diffusion-weighted imaging, perfusion MRI, and proton magnetic resonance spectroscopic imaging are more efficient than conventional MRI in differentiating PsP from TP. None of these techniques are fully effective, but current advances in computer science and the advent of artificial intelligence are opening up new possibilities in the imaging field with radiomics (i.e., extraction of a large number of quantitative MRI features describing tumor density, texture, and geometry). These features are used to build predictive models for diagnosis, prognosis, and therapeutic response.
METHOD
Out of 7350 records for MR spectroscopy, GBM, glioma, recurrence, diffusion, perfusion, pseudoprogression, radiomics, and advanced imaging, we screened 574 papers. A total of 228 were eligible, and we analyzed 72 of them, in order to establish the role of each imaging modality and the usefulness and limitations of radiomics analysis.
PubMed: 35203493
DOI: 10.3390/biomedicines10020285 -
Regulation of gut microbiome by ketogenic diet in neurodegenerative diseases: A molecular crosstalk.Frontiers in Aging Neuroscience 2022The gut taxonomical profile is one of the contributory factors in maintaining homeostasis within the central nervous system (CNS). Of late, the efficacy of diet as a...
The gut taxonomical profile is one of the contributory factors in maintaining homeostasis within the central nervous system (CNS). Of late, the efficacy of diet as a target of treatment, and how various dietary interventions may modulate gut microbiota differently have been an area of focus in research. The role of ketogenic diet (KD) in particular has been well-established in other diseases like intractable epilepsy due to its postulated effects on gut microbiome modulation, resulting in neuronal stability and prevention of epileptogenesis. Therefore, this systematic review aimed to critically evaluate the current available literature investigating the interplay between the three distinct entities: ketogenic diet, neurodegeneration, and gut microbiota, which may serve as a focus guide for future neurodegenerative diseases (ND) therapeutic research. A comprehensive literature search was performed on three databases; PubMed, Scopus, and Ovid Medline. A total of 12 articles were selected for critical appraisal, after subjecting to the inclusion and exclusion criteria in this study. The selected articles revealed that the hopes of KD as a treatment modality for ND are being ventured into as these individuals are said to acquire gut dysbiosis, primarily through increased colonization of phyla and . Although positive effects including restoration of healthy gut microbes such as sp., improvement in cognitive functioning and decline in neuro-inflammatory markers were noted, this systematic review also depicted conflicting results such as decrease in alpha and beta species diversity as well as diminution of healthy gut commensals such as . In addition, positive neuromodulation were also observed, notably an increase in cerebral blood perfusion to ventromedial hippocampal region increased expression of eNOS and clearance of amyloid-beta proteins across the blood-brain-barrier expression of p-glycoprotein. Neuroprotective mechanisms of ketogenic diet also included downregulation of mTOR expression, to prevention acceleration of pathological diseases such as Alzheimer's. Thus due to this conflicting/contrasting results demonstrated by ketogenic diet, such as a decline in gut species richness, diminution in beneficial microbes and decline cognition unless delivered in an intermittent fasting pattern, further studies may still be required before prior recommendation of a ketogenic diet therapeutic regime in ND patients.
PubMed: 36313018
DOI: 10.3389/fnagi.2022.1015837 -
Pediatric Radiology Sep 2023The role of postnatal Doppler measurements of the superior mesenteric artery (SMA) in detecting neonates at risk of necrotizing enterocolitis (NEC) remains uncertain;... (Meta-Analysis)
Meta-Analysis Review
The role of postnatal Doppler measurements of the superior mesenteric artery (SMA) in detecting neonates at risk of necrotizing enterocolitis (NEC) remains uncertain; therefore, we systematically reviewed and meta-analyzed the existing evidence regarding the usefulness of SMA Doppler measurements in detecting neonates at risk for NEC. We used the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, and we included studies which reported the following Doppler ultrasonography indices: peak systolic velocity, end-diastolic velocity, time average mean velocity, differential velocity, pulsatility index (PI) and resistive index. Eight studies were eligible for inclusion in the meta-analysis. Evidence suggested that, during the first postnatal day, neonates who developed NEC had a significantly higher peak systolic velocity (mean difference of 2.65 cm/s (95% confidence interval [CI] 1.23, 4.06, overall effect Z=3.66, P<0.001)), higher PI (mean difference of 1.52 (95% CI 0.00, 3.04, Z=1.96, P=0.05)) and higher resistive index (mean difference of 1.09 (95% CI 0.59, 1.60, Z=4.24, P<0.001)), compared to neonates who did not develop NEC. However, our findings do not support a strong association between the Doppler ultrasound indices and development of NEC at the time of disease onset. This meta-analysis suggests that first postnatal day SMA Doppler parameters, namely peak systolic velocity, PI and resistive index, are higher in neonates who develop NEC. On the other hand, the aforementioned indices are of uncertain significance once the diagnosis of NEC has been established.
Topics: Female; Infant, Newborn; Humans; Enterocolitis, Necrotizing; Mesenteric Artery, Superior; Ultrasonography; Ultrasonography, Doppler; Infant, Newborn, Diseases; Fetal Diseases; Blood Flow Velocity
PubMed: 37310444
DOI: 10.1007/s00247-023-05695-6 -
The Cochrane Database of Systematic... Oct 2022Premature ovarian insufficiency (POI) is a clinical syndrome resulting from loss of ovarian function before the age of 40. It is a state of hypergonadotropic... (Review)
Review
BACKGROUND
Premature ovarian insufficiency (POI) is a clinical syndrome resulting from loss of ovarian function before the age of 40. It is a state of hypergonadotropic hypogonadism, characterised by amenorrhoea or oligomenorrhoea, with low ovarian sex hormones (oestrogen deficiency) and elevated pituitary gonadotrophins. POI with primary amenorrhoea may occur as a result of chromosomal and genetic abnormalities, such as Turner syndrome, Fragile X, or autosomal gene defects; secondary amenorrhoea may be iatrogenic after the surgical removal of the ovaries, radiotherapy, or chemotherapy. Other causes include autoimmune diseases, viral infections, and environmental factors; in most cases, POI is idiopathic. Appropriate replacement of sex hormones in women with POI may facilitate the achievement of near normal uterine development. However, the optimal effective hormone therapy (HT) regimen to maximise the reproductive potential for women with POI remains unclear.
OBJECTIVES
To investigate the effectiveness and safety of different hormonal regimens on uterine and endometrial development in women with POI.
SEARCH METHODS
We searched the Cochrane Gynaecology and Fertility (CGF) Group trials register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, and two trials registers in September 2021. We also checked references of included studies, and contacted study authors to identify additional studies.
SELECTION CRITERIA
We included randomised controlled trials (RCTs) investigating the effect of various hormonal preparations on the uterine development of women diagnosed with POI.
DATA COLLECTION AND ANALYSIS
We used standard methodological procedures recommended by Cochrane. The primary review outcome was uterine volume; secondary outcomes were endometrial thickness, endometrial histology, uterine perfusion, reproductive outcomes, and any reported adverse events.
MAIN RESULTS
We included three studies (52 participants analysed in total) investigating the role of various hormonal preparations in three different contexts, which deemed meta-analysis unfeasible. We found very low-certainty evidence; the main limitation was very serious imprecision due to small sample size. Conjugated oral oestrogens versus transdermal 17ß-oestradiol We are uncertain of the effect of conjugated oral oestrogens compared to transdermal 17ß-oestradiol (mean difference (MD) -18.2 (mL), 95% confidence interval (CI) -23.18 to -13.22; 1 RCT, N = 12; very low-certainty evidence) on uterine volume, measured after 12 months of treatment. The study reported no other relevant outcomes (including adverse events). Low versus high 17ß-oestradiol dose We are uncertain of the effect of a lower dose of 17ß-oestradiol compared to a higher dose of 17ß-oestradiol on uterine volume after three or five years of treatment, or adverse events (1 RCT, N = 20; very low-certainty evidence). The study reported no other relevant outcomes. Oral versus vaginal administration of oestradiol and dydrogesterone We are uncertain of the effect of an oral or vaginal administration route on uterine volume and endometrial thickness after 14 or 21 days of administration (1 RCT, N = 20; very low-certainty evidence). The study reported no other relevant outcomes (including adverse events).
AUTHORS' CONCLUSIONS
No clear conclusions can be drawn in this systematic review, due to the very low-certainty of the evidence. There is a need for pragmatic, well designed, randomised controlled trials, with adequate power to detect differences between various HT regimens on uterine growth, endometrial development, and pregnancy outcomes following the transfer of donated gametes or embryos in women diagnosed with POI.
Topics: Amenorrhea; Dydrogesterone; Endometrium; Estradiol; Estrogens; Female; Humans; Menopause, Premature; Pregnancy
PubMed: 36200708
DOI: 10.1002/14651858.CD008209.pub2 -
Seminars in Nuclear Medicine Nov 2023Ventilation-perfusion (V/Q) lung scans constitute one of the oldest nuclear medicine procedures, remain one of the few studies performed in the acute setting, and are... (Review)
Review
Ventilation-perfusion (V/Q) lung scans constitute one of the oldest nuclear medicine procedures, remain one of the few studies performed in the acute setting, and are amongst the few performed in the emergency setting. V/Q studies have witnessed a long fluctuation in adoption rates in parallel to continuous advances in image processing and computer vision techniques. This review provides an overview on the status of artificial intelligence (AI) in V/Q scintigraphy. To clearly assess the past, current, and future role of AI in V/Q scans, we conducted a systematic Ovid MEDLINE(R) literature search from 1946 to August 5, 2022 in addition to a manual search. The literature was reviewed and summarized in terms of methodologies and results for the various applications of AI to V/Q scans. The PRISMA guidelines were followed. Thirty-one publications fulfilled our search criteria and were grouped into two distinct categories: (1) disease diagnosis/detection (N = 22, 71.0%) and (2) cross-modality image translation into V/Q images (N = 9, 29.0%). Studies on disease diagnosis and detection relied heavily on shallow artificial neural networks for acute pulmonary embolism (PE) diagnosis and were primarily published between the mid-1990s and early 2000s. Recent applications almost exclusively regard image translation tasks from CT to ventilation or perfusion images with modern algorithms, such as convolutional neural networks, and were published between 2019 and 2022. AI research in V/Q scintigraphy for acute PE diagnosis in the mid-90s to early 2000s yielded promising results but has since been largely neglected and thus have yet to benefit from today's state-of-the art machine-learning techniques, such as deep neural networks. Recently, the main application of AI for V/Q has shifted towards generating synthetic ventilation and perfusion images from CT. There is therefore considerable potential to expand and modernize the use of real V/Q studies with state-of-the-art deep learning approaches, especially for workflow optimization and PE detection at both acute and chronic stages. We discuss future challenges and potential directions to compensate for the lag in this domain and enhance the value of this traditional nuclear medicine scan.
Topics: Humans; Artificial Intelligence; Pulmonary Embolism; Lung; Radionuclide Imaging; Perfusion Imaging; Tomography, Emission-Computed, Single-Photon
PubMed: 37080822
DOI: 10.1053/j.semnuclmed.2023.03.002 -
CNS Neuroscience & Therapeutics Feb 2024Amyotrophic lateral sclerosis (ALS) is a progressive motor and extra-motor neurodegenerative disease. This systematic review aimed to examine MRI biomarkers and... (Review)
Review
BACKGROUND AND OBJECTIVE
Amyotrophic lateral sclerosis (ALS) is a progressive motor and extra-motor neurodegenerative disease. This systematic review aimed to examine MRI biomarkers and neuropsychological assessments of the hippocampal and parahippocampal regions in patients with ALS.
METHODS
A systematic review was conducted in the Scopus and PubMed databases for studies published between January 2000 and July 2023. The inclusion criteria were (1) MRI studies to assess hippocampal and parahippocampal regions in ALS patients, and (2) studies reporting neuropsychological data in patients with ALS.
RESULTS
A total of 46 studies were included. Structural MRI revealed hippocampal atrophy, especially in ALS-FTD, involving specific subregions (CA1, dentate gyrus). Disease progression and genetic factors impacted atrophy patterns. Diffusion tensor imaging (DTI) showed increased mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), and decreased fractional anisotropy (FA) in the hippocampal tracts and adjacent regions, indicating loss of neuronal and white matter integrity. Functional MRI (fMRI) revealed reduced functional connectivity (FC) between the hippocampus, parahippocampus, and other regions, suggesting disrupted networks. Perfusion MRI showed hypoperfusion in parahippocampal gyri. Magnetic resonance spectroscopy (MRS) found changes in the hippocampus, indicating neuronal loss. Neuropsychological tests showed associations between poorer memory and hippocampal atrophy or connectivity changes. CA1-2, dentate gyrus, and fimbria atrophy were correlated with worse memory.
CONCLUSIONS
The hippocampus and the connected regions are involved in ALS. Hippocampal atrophy disrupted connectivity and metabolite changes correlate with cognitive and functional decline. Specific subregions can be particularly affected. The hippocampus is a potential biomarker for disease monitoring and prognosis.
Topics: Humans; Diffusion Tensor Imaging; Amyotrophic Lateral Sclerosis; Neurodegenerative Diseases; Frontotemporal Dementia; Magnetic Resonance Imaging; Hippocampus; Biomarkers; Neuropsychological Tests; Atrophy
PubMed: 38334254
DOI: 10.1111/cns.14578 -
Digital Health 2022Image segmentation is an essential step in the analysis and subsequent characterisation of brain tumours through magnetic resonance imaging. In the literature,... (Review)
Review
BACKGROUND
Image segmentation is an essential step in the analysis and subsequent characterisation of brain tumours through magnetic resonance imaging. In the literature, segmentation methods are empowered by open-access magnetic resonance imaging datasets, such as the brain tumour segmentation dataset. Moreover, with the increased use of artificial intelligence methods in medical imaging, access to larger data repositories has become vital in method development.
PURPOSE
To determine what automated brain tumour segmentation techniques can medical imaging specialists and clinicians use to identify tumour components, compared to manual segmentation.
METHODS
We conducted a systematic review of 572 brain tumour segmentation studies during 2015-2020. We reviewed segmentation techniques using T1-weighted, T2-weighted, gadolinium-enhanced T1-weighted, fluid-attenuated inversion recovery, diffusion-weighted and perfusion-weighted magnetic resonance imaging sequences. Moreover, we assessed physics or mathematics-based methods, deep learning methods, and software-based or semi-automatic methods, as applied to magnetic resonance imaging techniques. Particularly, we synthesised each method as per the utilised magnetic resonance imaging sequences, study population, technical approach (such as deep learning) and performance score measures (such as Dice score).
STATISTICAL TESTS
We compared median Dice score in segmenting the whole tumour, tumour core and enhanced tumour.
RESULTS
We found that T1-weighted, gadolinium-enhanced T1-weighted, T2-weighted and fluid-attenuated inversion recovery magnetic resonance imaging are used the most in various segmentation algorithms. However, there is limited use of perfusion-weighted and diffusion-weighted magnetic resonance imaging. Moreover, we found that the U-Net deep learning technology is cited the most, and has high accuracy (Dice score 0.9) for magnetic resonance imaging-based brain tumour segmentation.
CONCLUSION
U-Net is a promising deep learning technology for magnetic resonance imaging-based brain tumour segmentation. The community should be encouraged to contribute open-access datasets so training, testing and validation of deep learning algorithms can be improved, particularly for diffusion- and perfusion-weighted magnetic resonance imaging, where there are limited datasets available.
PubMed: 35340900
DOI: 10.1177/20552076221074122 -
Inquiry : a Journal of Medical Care... 2023Turning and repositioning is considered one of the strategies to reduce the incidence of pressure injuries (PIs) among hospitalized patients, as it helps to redistribute... (Review)
Review
Turning and repositioning is considered one of the strategies to reduce the incidence of pressure injuries (PIs) among hospitalized patients, as it helps to redistribute and minimize direct pressure on the targeted skin and enhance blood perfusion in the affected areas. The frequency of turning and repositioning is generally uniform across clinical settings, with most clinical guidelines recommending a substantial change in a patient's position according to their health status. Notably, the optimal time interval between the position changes has not yet been established. Therefore, this study aimed to review the current literature in relation to the frequency of turning and repositioning adult patients to prevent PIs. The author used a systematic review following Whittemore and Knafl's review strategy. The author used the following databases: CINAHL, Scopus, PubMed, ProQuest, Ovid, MedLine, Web of Science, and Google Scholar. During the search, Boolean logic operators, MeSH terms, and keywords were utilized. The researcher followed the Johns Hopkins Nursing Evidence-based Practice Grading Scale to evaluate the quality of selected studies. The search yielded 723 articles, of which 10 were included in this review. These 10 articles revealed several frequency intervals for comparison purposes: 2-hourly, 3-hourly, 4-hourly, and 6-hourly depending on the healthcare setting, with a combination of supine, 30° tilt, or 90° tilt. This review shows that the optimal frequency of turning and repositioning to prevent PIs remains unclear and further investigation is necessary. Considering the varying nature of clinical settings, there is a lack of clarity regarding a golden standard for the same. Therefore, patients' health conditions should be considered when choosing the proper frequency to prevent PIs.
Topics: Humans; Adult; Pressure Ulcer; Health Facilities; Incidence; Health Status; Hospitals
PubMed: 38050921
DOI: 10.1177/00469580231215209