-
EJNMMI Physics Jul 2024Several factors may decrease the accuracy of quantitative PET myocardial perfusion imaging (MPI). It is therefore essential to ensure that myocardial blood flow (MBF)...
BACKGROUND
Several factors may decrease the accuracy of quantitative PET myocardial perfusion imaging (MPI). It is therefore essential to ensure that myocardial blood flow (MBF) values are reproducible and accurate, and to design systematic protocols to achieve this. Until now, no systematic phantom protocols have been available to assess the technical factors affecting measurement accuracy and reproducibility in MPI.
MATERIALS AND METHODS
We implemented a standard measurement protocol, which applies a flow phantom in order to compare image-derived flow values with respect to a ground truth flow value with [O]HO MPI performed on both a Discovery MI (DMI-20, GE Healthcare) and a Biograph Vision 600 (Vision-600, Siemens Healthineers) system. Both systems have automatic [O]HO radio water generators (Hidex Oy) individually installed, allowing us to also study the differences occurring due to two different bolus delivery systems. To investigate the technical factors contributing to the modelled flow values, we extracted the [O]HO bolus profiles, the flow values from the kinetic modeling (Qin and Qout), and finally calculated their differences between test-retest measurements on both systems.
RESULTS
The measurements performed on the DMI-20 system produced Qin and Qout values corresponging to each other as well as to the reference flow value across all test-retest measurements. The repeatability differences on DMI-20 were 2.1% ± 2.6% and 3.3% ± 4.1% for Qin and Qout, respectively. On Vision-600 they were 10% ± 8.4% and 11% ± 10% for Qin and Qout, respectively. The measurements performed on the Vision-600 system showed more variation between Qin and Qout values across test-retest measurements and exceeded 15% difference in 7/24 of the measurements.
CONCLUSIONS
A preliminary protocol for measuring the accuracy and reproducibility of flow values in [O]HO MPI between digital PET/CT systems was assessed. The test-retest reproducibility falls below 15% in majority of the measurements conducted between two individual injector systems and two digital PET/CT systems. This study highlights the importance of implementing a standardized bolus injection and delivery protocol and importance of assessing technical factors affecting flow value reproducibility, which should be carefully investigated in a multi-center setting.
PubMed: 38951352
DOI: 10.1186/s40658-024-00654-y -
Zhonghua Fu Chan Ke Za Zhi Jun 2024To investigate the effect of autologous platelet-rich plasma (PRP) perfusion on the levels of cytokines in uterine drainage fluid in patients with moderate to severe...
To investigate the effect of autologous platelet-rich plasma (PRP) perfusion on the levels of cytokines in uterine drainage fluid in patients with moderate to severe intrauterine adhesions (IUA) following hysteroscopic adhesiolysis. Thirty patients with moderate to severe IUA who underwent hysteroscopic adhesiolysis at Beijing Obstetrics and Gynecology Hospital, Capital Medical University from November 2020 to March 2021 were randomly divided into two groups: the PRP group (15 patients with placement of intrauterine-suitable balloons and PRP infusion) and the control group (15 patients with placement of intrauterine-suitable balloons only). For all patients, the channel switch was opened 48 hours after the surgery. The drainage fluid of the uterine cavity was collected using syringes through the proximal end of the drainage channel switch at 24 hours after the surgery and through the drainage channel directly at 48, 72, 96, and 120 hours after the surgery, and the levels of related cytokines including platelet-derived growth factor BB (PDGF-BB), vascular endothelial growth factor A (VEGF-A), insulin-like growth factor 1 (IGF-1) and transforming growth factor-β1 (TGF-β1) in the drainage fluid of the uterine cavity were evaluated, respectively. (1) The changes in volumes of uterine cavity drainage fluid: the total drainage fluid volumes of the PRP group and the control group in 120 hours after the surgery were (21.8±2.9) and (22.7±2.7) ml, respectively, and there was no statistically significant difference between the two groups (=-0.847, >0.05). No significant differences were found in the volumes of drainage fluid between the two groups at 72, 96, and 120 hours after the surgery (all >0.05). (2) Variation in cytokine levels in the uterine cavity drainage fluid: ① PDGF-BB: median PDGF-BB levels at 24 and 48 hours after the surgery in the PRP group (6.6 and 9.6 μg/L, respectively) were significantly higher than those in the control group (4.7 and 2.7 μg/L, respectively; all <0.05). There were no significant differences in PDGF-BB levels between the two groups at 72, 96, and 120 hours after the surgery (all >0.05). ② VEGF-A: median VEGF-A levels at 24 and 48 hours after the surgery in the PRP group (3.5 and 2.8 μg/L, respectively) were significantly higher than those in the control group (1.6 and 1.2 μg/L, respectively; all <0.05). There were no significant differences in VEGF-A levels between the two groups at 72, 96, and 120 hours after the surgery (all >0.05). ③ IGF-1: median IGF-1 level at 48 hours after the surgery in the PRP group was significantly higher than that in the control group (39.5 vs 8.6 μg/L, <0.05). No significant differences were found in IGF-1 levels at 24, 72, 96, and 120 hours after the surgery between the two groups (all >0.05). ④ TGF-β1: There were no significant differences in TGF-β1 levles between the two groups at 24, 48, 72, 96, and 120 hours after the surgery (all >0.05). PRP perfusion following hysteroscopic adhesiolysis may increase the levels of PDGF-BB, VEGF-A, and IGF-1 in the uterine cavity drainage fluid, which plays a beneficial role in improving wound microvascular formation, reducing adhesion reformation, and promoting endometrial regeneration and repair.
Topics: Humans; Female; Tissue Adhesions; Hysteroscopy; Platelet-Rich Plasma; Adult; Cytokines; Drainage; Uterine Diseases; Uterus; Vascular Endothelial Growth Factor A; Insulin-Like Growth Factor I; Becaplermin
PubMed: 38951079
DOI: 10.3760/cma.j.cn112141-20230811-00044 -
Journal of Vascular and Interventional... Jun 2024To evaluate efficacy of pulmonary arteriovenous malformation (PAVM) embolization using dual-energy computed tomography (DECT) and spectral curve analysis by...
PURPOSE
To evaluate efficacy of pulmonary arteriovenous malformation (PAVM) embolization using dual-energy computed tomography (DECT) and spectral curve analysis by characterizing contrast enhancement and vascular perfusion as a surrogate of the degree of vascular occlusion after embolotherapy.
METHODS
Nine consecutive adult patients underwent embolization for 21 PAVMs (size range 0.4-2.0cm; 15/21 simple angioarchitecture) and subsequent post-embolization chest DECT angiography. Twelve PAVMS were treated with vascular plugs ± coils, whereas nine PAVMs were treated with coils-only. Virtual spectral curves (VSC) were generated using dual-energy image post-processing in order to measure embolization effectiveness.
RESULTS
Complete occlusion of target PAVM was achieved in all cases on digital subtraction angiography at the end of the embolization procedure. With a median follow-up of 12.7 months, the vascular plug group demonstrated significantly less vascular opacification compared to the coils-only group, as measured by opacification between upstream feeding artery and and different downstream vasculature locations (Δslope1: median 79.1 versus 28.6, p=0.0030; Δslope2: 76.4 versus 28.6, p=0.0197; Δslope3: 78.9 versus 28.6, p=0.0041). Persistence occurred in three PAVMs based on size criteria, which demonstrated higher vascular vascular opacification by DECT (Δslope1: 72 versus 28.6, p=0.253; Δslope2: 65.1 versus 32.7, p=0.326; Δslope3: 72.9 versus 53.5, p=0.733), although statistical significance was not reached.
CONCLUSION
Similar to emerging literature, DECT showed improved occlusion in PAVMs treated with vascular plugs compared to coils alone.
PubMed: 38950821
DOI: 10.1016/j.jvir.2024.06.027 -
Talanta Jun 2024Tumor spheroids are widely studied for in vitro modeling of tumor growth and responses to anticancer drugs. However, current methods are mostly limited to static and...
Tumor spheroids are widely studied for in vitro modeling of tumor growth and responses to anticancer drugs. However, current methods are mostly limited to static and perfusion-based cultures, which can be improved by more accurately mimicking pathological conditions. Here, we developed a diffusion-based dynamic culture system for tumor spheroids studies using a thin membrane of hydrogel microwells and a microfluidic device. This allows for effective exchange of nutrients and metabolites between the tumors and the culture medium flowing underneath, resulting in uniform tumor spheroids. To monitor the growth and drug response of the spheroids in real-time, we performed spectroscopic analyses of the system's impedance, demonstrating a close correlation between the tumor size and the resistance and capacitance of the system. Our results also indicate an enhanced drug effect on the tumor spheroids in the presence of a low AC electric field, suggesting a weakening mechanism of the spheroids induced by external perturbation.
PubMed: 38950503
DOI: 10.1016/j.talanta.2024.126473 -
PloS One 2024The placenta is a transient organ critical for fetal development. Disruptions of normal placental functions can impact health throughout an individual's entire life....
BACKGROUND
The placenta is a transient organ critical for fetal development. Disruptions of normal placental functions can impact health throughout an individual's entire life. Although being recognized by the NIH Human Placenta Project as an important organ, the placenta remains understudied, partly because of a lack of non-invasive tools for longitudinally evaluation for key aspects of placental functionalities.
OBJECTIVE
Our goal is to create a non-invasive preclinical imaging pipeline that can longitudinally probe murine placental health in vivo. We use advanced imaging processing schemes to establish functional biomarkers for non-invasive longitudinal evaluation of placental development.
METHODOLOGY
We implement dynamic contrast enhancement magnetic resonance imaging (DCE-MRI) and analysis pipeline to quantify uterine contraction and placental perfusion dynamics. We use optic flow and time-frequency analysis to quantify and characterize contraction-related placental motion. Our novel imaging and analysis pipeline uses subcutaneous administration of gadolinium for steepest slope-based perfusion evaluation, enabling non-invasive longitudinal monitoring.
RESULTS
We demonstrate that the placenta exhibits spatially asymmetric contractile motion that develops from E14.5 to E17.5. Additionally, we see that placental perfusion, perfusion delivery rate, and substrate delivery all increase from E14.5 to E17.5, with the High Perfusion Chamber (HPC) leading the placental changes that occur from E14.5 to E17.5.
DISCUSSION
We advance the placental perfusion chamber paradigm with a novel, physiologically based threshold model for chamber localization and demonstrate spatially varying placental chambers using multiple functional metrics that assess mouse placental development and remodeling throughout gestation.
CONCLUSION
Our pipeline enables the non-invasive, longitudinal assessment of multiple placenta functions from a single imaging session. Our pipeline serves as a key toolbox for advancing research in mouse models of placental disease and disorder.
Topics: Animals; Female; Pregnancy; Magnetic Resonance Imaging; Mice; Placenta; Uterine Contraction; Contrast Media; Mice, Inbred C57BL
PubMed: 38950083
DOI: 10.1371/journal.pone.0303957 -
Minerva Cardiology and Angiology Jul 2024Heart failure (HF) is a clinical syndrome which is due to cardiac structural and/or functional abnormalities that result in elevated intra-cardiac pressures and/or...
Heart failure (HF) is a clinical syndrome which is due to cardiac structural and/or functional abnormalities that result in elevated intra-cardiac pressures and/or inadequate cardiac output. Hemodynamic assessment in HF allows the identification and characterization of cardiac dysfunction, systemic and/or pulmonary congestion and the eventual impairment of systemic perfusion which are fundamental to phenotype HF, risk stratify HF patients and to guide their treatment. Patient hemodynamics can be characterized invasively with right heart catheterization but also non-invasively with the use of echocardiography and other non-invasive ultrasound tools. The aim of the present review is to summarize the main echocardiographic and ultrasound parameters to characterize the hemodynamics of patients with HF and help clinicians to make the most of these non-invasive tools to guide HF patient management.
PubMed: 38949760
DOI: 10.23736/S2724-5683.24.06471-8 -
International Journal of Cancer Jul 2024Gliomas are primary brain tumors and are among the most malignant types. Adult-type diffuse gliomas can be classified based on their histological and molecular...
Gliomas are primary brain tumors and are among the most malignant types. Adult-type diffuse gliomas can be classified based on their histological and molecular signatures as IDH-wildtype glioblastoma, IDH-mutant astrocytoma, and IDH-mutant and 1p/19q-codeleted oligodendroglioma. Recent studies have shown that each subtype of glioma has its own specific distribution pattern. However, the mechanisms underlying the specific distributions of glioma subtypes are not entirely clear despite partial explanations such as cell origin. To investigate the impact of multi-scale brain attributes on glioma distribution, we constructed cumulative frequency maps for diffuse glioma subtypes based on T1w structural images and evaluated the spatial correlation between tumor frequency and diverse brain attributes, including postmortem gene expression, functional connectivity metrics, cerebral perfusion, glucose metabolism, and neurotransmitter signaling. Regression models were constructed to evaluate the contribution of these factors to the anatomic distribution of different glioma subtypes. Our findings revealed that the three different subtypes of gliomas had distinct distribution patterns, showing spatial preferences toward different brain environmental attributes. Glioblastomas were especially likely to occur in regions enriched with synapse-related pathways and diverse neurotransmitter receptors. Astrocytomas and oligodendrogliomas preferentially occurred in areas enriched with genes associated with neutrophil-mediated immune responses. The functional network characteristics and neurotransmitter distribution also contributed to oligodendroglioma distribution. Our results suggest that different brain transcriptomic, neurotransmitter, and connectomic attributes are the factors that determine the specific distributions of glioma subtypes. These findings highlight the importance of bridging diverse scales of biological organization when studying neurological dysfunction.
PubMed: 38949756
DOI: 10.1002/ijc.35068 -
Artificial Organs Jul 2024Liver transplantation is used for treating end-stage liver disease, fulminant hepatitis, and oncological malignancies and organ shortage is a major limiting factor...
BACKGROUND
Liver transplantation is used for treating end-stage liver disease, fulminant hepatitis, and oncological malignancies and organ shortage is a major limiting factor worldwide. The use of grafts based on extended donor criteria have become internationally accepted. Oxygenated machine perfusion technologies are the most recent advances in organ transplantation; however, it is only applied after a period of cold ischemia. Due to its high cost, we aimed to use a novel device, OxyFlush®, based on oxygenation of the preservation solution, applied during liver procurement targeting the maintenance of ATP during static cold storage (SCS).
METHODS
Twenty patients were randomly assigned to the OxyFlush or control group based on a 1:1 ratio. In the OxyFlush group, the perfusion solution was oxygenated with OxyFlush® device while the control group received a non-oxygenated solution. Liver and the common bile duct (CBD) biopsies were obtained at three different time points. The first was at the beginning of the procedure, the second during organ preparation, and the third after total liver reperfusion. Biopsies were analyzed, and adenosine triphosphate (ATP) levels and histological scores of the liver parenchyma and CBD were assessed. Postoperative laboratory tests were performed.
RESULTS
OxyFlush® was able to maintain ATP levels during SCS and improved the damage caused by the lack of oxygen in the CBD. However, OxyFlush® did not affect laboratory test results and histological findings of the parenchyma.
CONCLUSION
We present a novel low-cost device that is feasible and could represent a valuable tool in organ preservation during SCS.
PubMed: 38949484
DOI: 10.1111/aor.14815 -
Minerva Anestesiologica Jul 2024Brain dysfunction is a frequent complication of sepsis. Most likely, sepsis-associated brain dysfunction (SABD) results from the interaction between multiple factors:...
Brain dysfunction is a frequent complication of sepsis. Most likely, sepsis-associated brain dysfunction (SABD) results from the interaction between multiple factors: neurodegeneration due to microglial activation, altered neurotransmission, neuroinflammation and impairment of cerebral macro- and microcirculation. Altered brain perfusion might results from several mechanism: global or regional alterations in cerebral blood flow (CBF); reduced cerebral perfusion pressure - which is the driving force propelling blood through cerebral blood vessels - due to systemic hypotension; global or regional vasoconstriction; dysfunction of the intrinsic regulatory mechanisms of CBF, such as cerebral autoregulation and cerebrovascular reactivity; endothelial and blood-brain barrier dysfunction; autonomic nervous system dysfunction and metabolic uncoupling. Disorders of brain perfusion and CBF regulation are frequently observed in humans with sepsis, and intracranial hemodynamics monitoring can potentially be useful in clinical management of septic patients. The aim of this review is to provide an update of the current knowledge on alterations in brain hemodynamics associated with sepsis, along with physiological and methodological considerations intended to help the reader navigate the diverse results from published literature and a practical guide to apply non-invasive intracranial hemodynamics monitoring to septic patients in clinical practice.
PubMed: 38949458
DOI: 10.23736/S0375-9393.24.17978-3 -
Molecular Imaging and Radionuclide... Jun 2024To quantitatively evaluate the performance of the most used colormaps in image display using perceptual metrics and to what extent these measures are congruent with the...
OBJECTIVES
To quantitatively evaluate the performance of the most used colormaps in image display using perceptual metrics and to what extent these measures are congruent with the true intensity or uptake of pixels at different levels of defect severity in simulated cardiac images.
METHODS
Six colormaps, labeled "Gray", "Thermal", "Cool", "CEqual", "Siemens" and "S Pet" extracted from FIJI ImageJ software are included. Colormap data are converted from the red, green, blue color space to CIELAB. Perceptual metrics for measuring "color difference" were calculated, including difference (ΔE) and "speed". The pairwise color difference in every two levels or entries is visualized in a 2-dimensional "heatmap distance matrix" for each colormap. Curves are plotted for each colormap and compared. In addition, to apply this technique to clinical images, simulated short-axis cardiac slices with incremental defect severity (10% grading) were employed. The circumferential profile curves of true pixel intensity, lightness or luminance, and color difference are plotted simultaneously for each defect severity to visualize the concordance of the three curves in various colormaps.
RESULTS
In 0% defect, all the curves are at the highest level, except for "s pet", in that the lightness is not at its maximum value. In the phantom with 10% defect (or 90% of maximum value), discrepancies among curves appear. In "Siemens", the ΔE drops sharply. In "Siemens" colormap, the ΔE drops sharply. In 80% defect, ΔE curve, in "gray" colormap drops more slowly than other curves of other colormaps. In "s pet", lightness curve rises paradoxically, although the count intensity and ΔE curve match. In 70% defect, again, the curves are in good agreement in "thermal", "Siemens" and "cequal". However, a consistent lag exists in "gray". Up to 50% defect, curves maintain their expected pattern, but in defects more severe than 40%, lightness and ΔE curves in "cool" and "cequal" rise paradoxically, and in "thermal", they start to slow down in descent. In "Siemens", falling pattern of the three curves continues. For "s pet" colormap, an erratic pattern of lightness and ΔE curves exists.
CONCLUSION
Of 6 colormaps investigated for estimating defect severity, "grayscale" is less favorable than others and "thermal" performs slightly better. "S pet" or rainbow, which is used traditionally by many practitioners, is strongly discouraged. The "Siemens" colormap suffers from decreased discriminating power in the range of mild to moderate/severe. In contrast, the "cool" and "cequal" colormaps outperform the other colormaps employed in this study to some extent, although they have some shortcomings.
PubMed: 38949419
DOI: 10.4274/mirt.galenos.2024.34711