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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 -
Frontiers in Neurology 2023Computed tomography perfusion (CTP) has successfully extended the time window for reperfusion therapies in ischemic stroke. However, the published perfusion parameters...
BACKGROUND AND PURPOSE
Computed tomography perfusion (CTP) has successfully extended the time window for reperfusion therapies in ischemic stroke. However, the published perfusion parameters and thresholds vary between studies. Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses of Diagnostic Test Accuracy Studies (PRISMA-DTA) guidelines, we conducted a systematic review to investigate the accuracy of parameters and thresholds for identifying core and penumbra in adult stroke patients.
METHODS
We searched Medline, Embase, the Cochrane Library, and reference lists of manuscripts up to April 2022 using the following terms "computed tomography perfusion," "stroke," "infarct," and "penumbra." Studies were included if they reported perfusion thresholds and undertook co-registration of CTP to reference standards. The quality of studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool and Standards for Reporting of Diagnostic Accuracy (STARD) guidelines.
RESULTS
A total of 24 studies were included. A meta-analysis could not be performed due to insufficient data and significant heterogeneity in the study design. When reported, the mean age was 70.2 years (SD+/-3.69), and the median NIHSS on admission was 15 (IQR 13-17). The perfusion parameter identified for the core was relative cerebral blood flow (rCBF), with a median threshold of <30% (IQR 30, 40%). However, later studies reported lower thresholds in the early time window with rapid reperfusion (median 25%, IQR 20, 30%). A total of 15 studies defined a single threshold for all brain regions irrespective of collaterals and the gray and white matter.
CONCLUSION
A single threshold and parameter may not always accurately differentiate penumbra from core and oligemia. Further refinement of parameters is needed in the current era of reperfusion therapy.
PubMed: 37885475
DOI: 10.3389/fneur.2023.1255526 -
Frontiers in Medicine 2023Pulmonary hypertension due to chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD) is classified as group 3 pulmonary hypertension. Inhaled... (Review)
Review
BACKGROUND
Pulmonary hypertension due to chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD) is classified as group 3 pulmonary hypertension. Inhaled treprostinil, a prostaglandin I analogue also known as prostacyclin, has recently been approved as a first drug for patients with pulmonary hypertension secondary to ILD. However, due to a lack of evidence, no therapies are currently approved for those with COPD-associated pulmonary hypertension. Thus, this systematic review aims to summarise the current evidence to assess the impact of inhaled prostaglandin I analogue use on the pulmonary hemodynamics, exercise function, lung function, and gas exchange in patients with pulmonary hypertension due to COPD.
METHODS
We systematically searched the electronic databases of Medline, Embase, Scopus and Cochrane from inception to 1 February 2023. Studies of adult patients with a confirmed diagnosis of COPD-associated pulmonary hypertension who received inhaled drugs targeting the prostacyclin pathway were included in the systematic review. Case reports, systematic reviews, conference abstracts with no full text, non-full-text articles, non-English manuscripts and book chapters were excluded from this systematic review. A risk-of-bias assessment was carried out for the studies included in this review, using two different Cochrane risk-of-bias tools for randomised and non-randomised clinical trials.
RESULTS
A total of four studies met our inclusion criteria and were included in this systematic review. The results of one prospective clinical trial showed an improvement in the pulmonary hemodynamics (e.g., cardiac index, cardiac output and mean pulmonary artery pressure) in response to inhaled prostacyclin use in patients with pulmonary hypertension secondary to COPD. However, the severity of dyspnoea, lung function, exercise capacity and gas exchange were not affected when inhaled prostacyclin was used for patients with COPD-related pulmonary hypertension.
CONCLUSION
This systematic review demonstrated that although inhaled prostacyclin does not seem to improve COPD-related outcomes (e.g., lung function and exercise capacity), short-term use of inhaled prostacyclin has the potential to reduce mean pulmonary artery pressure and pulmonary vascular resistance without impairing ventilation-perfusion mismatch. Further studies with larger sample sizes are warranted.
SYSTEMATIC REVIEW REGISTRATION
CRD42022372803, https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=372803.
PubMed: 37706024
DOI: 10.3389/fmed.2023.1217156 -
CNS Neuroscience & Therapeutics Apr 2024Stroke is a leading cause of global morbidity and mortality, indicating the necessity and urgency of effective prevention and treatment. Remote ischemic conditioning... (Review)
Review
BACKGROUND AND PURPOSE
Stroke is a leading cause of global morbidity and mortality, indicating the necessity and urgency of effective prevention and treatment. Remote ischemic conditioning (RIC) is a convenient, simple, non-intrusive, and effective method that can be easily added to the treatment regime of stroke patients. Animal experiments and clinical trials have proved the neuroprotective effects of RIC on brain injury including (examples of neuroprotective effects). This neuroprotection is achieved by raising brain tolerance to ischemia, increasing local cerebral blood perfusion, promoting collateral circulations, neural regeneration, and reducing the incidence of hematomas in brain tissue. This current paper will summarize the studies within the last 2 years for the comprehensive understanding of the use of RIC in the treatment of stroke.
METHODS
This paper summarizes the clinical research progress of RIC on stroke (ischemic stroke and hemorrhagic stroke (HS)). This paper is a systematic review of research published on registered clinical trials using RIC in stroke from inception through November 2022. Four major databases (PUBMED, WEB OF SCIENCE, EMBASE, and ClinicalTrials.gov) were searched.
RESULTS
Forty-eight studies were identified meeting our criteria. Of these studies, 14 were in patients with acute ischemic stroke with onset times ranging from 6 h to 14 days, seven were in patients with intravenous thrombolysis or endovascular thrombectomy, 10 were in patients with intracranial atherosclerotic stenosis, six on patients with vascular cognitive impairment, three on patients with moyamoya disease, and eight on patients with HS. Of the 48 studies, 42 were completed and six are ongoing.
CONCLUSIONS
RIC is safe, feasible, and effective in the treatment of stroke. Large-scale research is still required to explore the optimal treatment options and mechanisms of RIC in the future to develop a breakthrough in stroke prevention and treatment.
Topics: Animals; Humans; Brain Ischemia; Ischemic Stroke; Neuroprotective Agents; Ischemic Preconditioning; Stroke; Ischemia
PubMed: 37927203
DOI: 10.1111/cns.14507 -
European Journal of Nuclear Medicine... Oct 2023Aim of this study was to define the prognostic value of stress myocardial perfusion imaging by cadmium zinc telluride (CZT) single-photon emission computed tomography... (Meta-Analysis)
Meta-Analysis
Prognostic value of myocardial perfusion imaging by cadmium zinc telluride single-photon emission computed tomography in patients with suspected or known coronary artery disease: a systematic review and meta-analysis.
BACKGROUND
Aim of this study was to define the prognostic value of stress myocardial perfusion imaging by cadmium zinc telluride (CZT) single-photon emission computed tomography (SPECT) for prediction of adverse cardiovascular events in patients with known or suspected coronary artery disease (CAD).
METHODS AND RESULTS
Studies published until November 2022 were identified by database search. We included studies using stress myocardial perfusion imaging by CZT-SPECT to evaluate subjects with known or suspected CAD and providing primary data of adverse cardiovascular events. Total of 12 studies were finally included recruiting 36,415 patients. Pooled hazard ratio (HR) for the occurrence of adverse events was 2.17 (95% confidence interval, CI, 1.78-2.65) and heterogeneity was 66.1% (P = 0.001). Five studies reported data on adjusted HR for the occurrence of adverse events. Pooled HR was 1.69 (95% CI, 1.44-1.98) and heterogeneity was 44.9% (P = 0.123). Seven studies reported data on unadjusted HR for the occurrence of adverse events. Pooled HR was 2.72 (95% CI, 2.00-3.70). Nine studies reported data useful to calculate separately the incidence rate of adverse events in patients with abnormal and normal myocardial perfusion. Pooled incidence rate ratio was 2.38 (95% CI, 1.39-4.06) and heterogeneity was 84.6% (P < 0.001). The funnel plot showed no evidence of asymmetry (P = 0.517). At meta-regression analysis, we found an association between HR for adverse events and presence of angina symptoms and family history of CAD.
CONCLUSIONS
Stress myocardial perfusion imaging by CZT-SPECT is a valuable noninvasive prognostic indicator for adverse cardiovascular events in patients with known or suspected CAD.
Topics: Humans; Coronary Artery Disease; Cadmium; Myocardial Perfusion Imaging; Prognosis; Tomography, Emission-Computed
PubMed: 37480369
DOI: 10.1007/s00259-023-06344-8 -
Journal of Pediatric Surgery Aug 2023Although ICG-FA may be valuable in assessing anastomotic perfusion, reliable data on its use in pediatric gastrointestinal surgery is lacking. This systematic review... (Review)
Review
BACKGROUND
Although ICG-FA may be valuable in assessing anastomotic perfusion, reliable data on its use in pediatric gastrointestinal surgery is lacking. This systematic review analyzes whether ICG is useful for intestinal perfusion assessment in pediatric gastrointestinal surgery and safe to use in neonates.
METHODS
Systematic searches of PubMed, EMBASE & MEDLINE and CENTRAL were performed (last conducted December 6, 2021). The main inclusion criteria were (1) use of ICG for intestinal perfusion assessment and (2) use of ICG in young infants. Exclusion criteria were lack of an English or Dutch full-text and MINORS quality score <60%. Data was presented in overview tables. The usefulness in pediatric gastrointestinal surgery was assessed by surgical outcome. Safety of ICG in neonates was assessed by complication or adverse event occurrence.
RESULTS
Regarding intestinal perfusion assessment, four studies were included, reporting 45 patients (median age 1.5 years). ICG was considered useful for anastomotic blood flow evaluation and intraoperative determination of resection length. Regarding ICG safety in neonates, eight studies were included, reporting 46 infants (median age 24.9 days), of which 18 neonates. All but one studies reported the absence of complications or adverse events. Two studies reported subcutaneous dye retention, which fully disappeared within two weeks.
CONCLUSION
Although the number of available studies is small, ICG might be useful for intraoperative intestinal perfusion assessment, perhaps even more than conventional clinical assessment. Furthermore, its safety profile looks promising in neonates. Larger prospective studies are necessary to confirm these assumptions and seem warranted given the safety profile.
LEVELS OF EVIDENCE
Since this is a systematic review, a Level of Evidence for clinical studies cannot be determined for this manuscript.
Topics: Infant, Newborn; Humans; Child; Infant; Indocyanine Green; Fluorescein Angiography; Anastomotic Leak; Coloring Agents; Prospective Studies; Feasibility Studies; Digestive System Surgical Procedures; Anastomosis, Surgical
PubMed: 36404183
DOI: 10.1016/j.jpedsurg.2022.10.045 -
BJS Open Sep 2023Conflicting evidence exists regarding the optimal waiting time for stable analgesic and vasoconstrictive effects after local infiltration of lidocaine with epinephrine....
BACKGROUND
Conflicting evidence exists regarding the optimal waiting time for stable analgesic and vasoconstrictive effects after local infiltration of lidocaine with epinephrine. An objective review is needed to dispel surgical dogma.
METHODS
This systematic review (PROSPERO ID: CRD42022362414) included RCTs and prospective cohort studies. Primary outcomes were (1) onset of analgesia and (2) onset of stable hypoperfusion, assessed directly, or measured indirectly using perfusion imaging. Other data extracted include waiting strategies, means of outcome assessment, anaesthetic concentrations, volume/endpoint of infiltration, and injection sites. Methodological quality was evaluated using the Cochrane risk-of-bias tool for randomized trials. Articles describing waiting strategies were critically appraised by the Joanna Briggs Institute tools.
RESULTS
Twenty-four articles were analysed, comprising 1013 participants. Ten investigated analgesia onset. Their pooled mean was 2.1 min (range 0.4-9.0 min). This varied with anatomic site and targeted nerve diameter. Fourteen articles investigated onset of stable hypoperfusion. Four observed bleeding intraoperatively, finding the minimum time to hypoperfusion at 7.0 min in the eyelid skin and 25.0 min in the upper limb. The ten remaining studies used perfusion imaging, reporting a wide range of results (0.0-30.0 min) due to differences in anatomic sites and depth, resolution and artefacts. Studies using near-infrared reflectance spectroscopy and hyperspectral imaging correlated with clinical observations. Thirteen articles discussed waiting strategies, seven relating to large-volume tumescent local infiltration anaesthesia. Different waiting strategies exist for emergency, arthroscopic and cosmetic surgeries, according to the degree of hypoperfusion required. In tumescent liposuction, waiting 10.0-60.0 min is the norm.
CONCLUSION
Current literature suggests that around 2 min are required for most patients to achieve complete analgesia in all sites and with all anaesthesia concentrations. Waiting around 7 min in eyelids and at least 25 min in other regions results in optimal hypoperfusion. The strategies discussed inform decisions of when and how long to wait.
Topics: Humans; Anesthesia, Local; Prospective Studies; Pain Management; Epinephrine; Lidocaine
PubMed: 37768699
DOI: 10.1093/bjsopen/zrad089 -
Cureus Aug 2023Stroke, a prevalent medical emergency, comprises ischemic and hemorrhagic subtypes, with acute ischemic stroke (AIS) being a predominant type. The application of... (Review)
Review
Stroke, a prevalent medical emergency, comprises ischemic and hemorrhagic subtypes, with acute ischemic stroke (AIS) being a predominant type. The application of computed tomography perfusion (CTP) imaging has gained prominence due to its rapidity and accessibility in stroke evaluation. This study systematically reviews and conducts a meta-analysis of existing literature to assess the diagnostic accuracy of CTP in detecting AIS and predicting hemorrhagic transformation (HT). Employing Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, an extensive search was conducted across electronic databases and relevant radiology journals. Studies conducted between 2007 and 2023 that fulfilled predetermined inclusion criteria underwent quality assessment using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS 2) tool. Cochrane diagnostic accuracy tools were used for data extraction. Thirteen studies involving a total of 1014 patients were included in the analysis. The diagnostic performance of CTP in predicting HT demonstrated high sensitivity (86.7%) and moderate specificity (77.8%), resulting in an overall accuracy of 79.1%. The negative predictive value (NPV) was notably high (92.9%), signifying its efficacy in excluding patients at risk of HT. The positive predictive value (PPV) was comparatively lower (60.3%), highlighting the need for clinical context when making thrombolysis decisions. The false positive rate was 16.2%, while the false negative rate was minimal (9.8%). Subgroup analysis underscored consistent sensitivity and specificity across diverse imaging metrics. The findings of this study emphasize the promising diagnostic accuracy of CTP imaging in predicting HT subsequent to AIS. This non-invasive technique can aid treatment decisions and patient management strategies. By effectively assessing perfusion status and offering predictive insights, CTP imaging improves stroke intervention choices, especially in identifying patients with a lower risk of HT.
PubMed: 37791142
DOI: 10.7759/cureus.44396 -
Cancers Oct 2023Magnetic resonance imaging (MRI) is an indispensable, routine technique that provides morphological and functional imaging sequences. MRI can potentially capture tumor... (Review)
Review
Magnetic resonance imaging (MRI) is an indispensable, routine technique that provides morphological and functional imaging sequences. MRI can potentially capture tumor biology and allow for longitudinal evaluation of head and neck squamous cell carcinoma (HNSCC). This systematic review and meta-analysis evaluates the ability of MRI to predict tumor biology in primary HNSCC. Studies were screened, selected, and assessed for quality using appropriate tools according to the PRISMA criteria. Fifty-eight articles were analyzed, examining the relationship between (functional) MRI parameters and biological features and genetics. Most studies focused on HPV status associations, revealing that HPV-positive tumors consistently exhibited lower (SMD: 0.82; < 0.001) and (SMD: 0.56; < 0.001) values. On average, lower values are associated with high Ki-67 levels, linking this diffusion restriction to high cellularity. Several perfusion parameters of the vascular compartment were significantly associated with HIF-1α. Analysis of other biological factors (VEGF, EGFR, tumor cell count, p53, and MVD) yielded inconclusive results. Larger datasets with homogenous acquisition are required to develop and test radiomic-based prediction models capable of capturing different aspects of the underlying tumor biology. Overall, our study shows that rapid and non-invasive characterization of tumor biology via MRI is feasible and could enhance clinical outcome predictions and personalized patient management for HNSCC.
PubMed: 37894447
DOI: 10.3390/cancers15205077 -
Frontiers in Physiology 2023Studies have shown that exercise increases angiogenesis and perfusion in the hippocampus, activates neurogenesis in the dentate gyrus and increases synaptic plasticity,...
Studies have shown that exercise increases angiogenesis and perfusion in the hippocampus, activates neurogenesis in the dentate gyrus and increases synaptic plasticity, as well as increases the complexity and number of dendritic spines, all of which promote memory function and protect against cognitive decline. Flavonoids are gaining attention as antioxidants in health promotion due to their rich phenolic content, particularly for their modulating role in the treatment of neurodegenerative diseases. Despite this, there has been no comprehensive review of cognitive improvement supplemented with flavonoid and prescribed with exercise or a combination of the two interventions has been conducted. The purpose of this review is to determine whether a combined intervention produces better results when given together than when given separately. Relevant articles assessing the effect of physical exercise, flavonoid or in combination on cognitive related biomarkers and neurobehavioral assessments within the timeline of January 2011 until June 2023 were searched using three databases; PubMed, PROQUEST and SCOPUS. A total of 705 articles were retrieved and screened, resulting in 108 studies which are in line with the objective of the current study were included in the analysis. The selected studies have shown significant desired effect on the chosen biomarkers and neurobehavioral assessments. identifier: [CRD42021271001].
PubMed: 37664425
DOI: 10.3389/fphys.2023.1216948