Perfusion Technique Research Articles

Perfusion MRI Techniques: Beyond DSC

The use of brain hemodynamics is important in the assessment of numerous pathophysiologic conditions. The measurement of perfusion or delivery of blood to tissues by MR imaging is essential for neuroradiologists to understand and appropriately apply to clinical practice. Several different approaches are used. DSC and dynamic contrast-enhanced MR imaging study the signal change (according to T2* and T1, respectively) induced by an exogenous contrast agent, allowing the measurement of CBF, CBV, and time-related parameters. Blood oxygen level‐dependent (BOLD) MR imaging measures the T2* signal changes induced by the paramagnetic molecule deoxyhemoglobin. BOLD MR imaging provides complex measurements because the signal varies not only with changes in CBF but also with several other parameters such as tissular oxygen uptake and brain activation. Arterial spin-labeling MR imaging is a technique relying on labeled endogenous water as a tracer. By measuring the signal difference between 2 sets of acquisitions (labeling and control), arterial spin-labeling MR imaging calculates cerebral perfusion in a quantitative manner. This article aims to review the fundamentals of perfusion MR imaging techniques essential to any neuroradiology practice along with their advantages, disadvantages, and applications to research and clinical care.Learning Objective: To review DSC MR imaging and alternative MR imaging perfusion techniques, focusing on methodology, advancements, and applications essential for the neuroradiologist to understand and clinically use these techniques

Evaluation and timing optimization of CT perfusion first pass analysis in comparison to maximum slope model in pancreatic adenocarcinoma

For implementation, performance evaluation and timing optimization of CT perfusion first pass analysis (FPA) by correlation with maximum slope model (MSM) in pancreatic adenocarcinoma, dynamic CT perfusion acquisitions of 34 time-points were performed in 16 pancreatic adenocarcinoma patients. Regions of interest were marked in both parenchyma and carcinoma. FPA, a low radiation exposure CT perfusion technique, was implemented. Blood flow (BF) perfusion maps were calculated using FPA and MSM. Pearson’s correlation between FPA and MSM was calculated at each evaluated time-point to determine optimum timing for FPA. Differences in BF between parenchyma and carcinoma were calculated. Average BF for MSM was 106.8 ± 41.5 ml/100 ml/min in parenchyma and 42.0 ± 24.8 ml/100 ml/min in carcinoma, respectively. For FPA, values ranged from 85.6 ± 37.5 ml/100 ml/min to 117.7 ± 44.5 ml/100 ml/min in parenchyma and from 27.3 ± 18.8 ml/100 ml/min to 39.5 ± 26.6 ml/100 ml/min in carcinoma, depending on acquisition timing. A significant difference (p value < 0.0001) between carcinoma and parenchyma was observed at all acquisition times based on FPA measurements. FPA shows high correlation with MSM (r > 0.90) and 94% reduction in the radiation dose compared to MSM. CT perfusion FPA, where the first scan is obtained after the arterial input function exceeds a threshold of 120 HU, followed by a second scan after 15.5–20.0 s, could be used as a potential imaging biomarker with low radiation exposure for diagnosing and evaluating pancreatic carcinoma in clinical practice, showing high correlation with MSM and the ability to differentiate between parenchyma and carcinoma.

White and Gray Matter Perfusion in Children with Moyamoya Angiopathy after Revascularization Surgery

Introduction: Surgical revascularization is very effective in patients with moyamoya angiopathy (MMA) and leads to improvements in cortical perfusion parameters. However, changes in white matter hemodynamics are still underestimated. To date, only a few studies have examined brain perfusion changes within deep white matter after bypass surgery in patients with MMA. Methods: Ten children with MMA were evaluated using the CT perfusion technique before and after revascularization surgery. Brain perfusion parameters within gray and white matter were compared before and after surgery. The correlations between the perfusion parameters before surgery and the Suzuki stage, as well as between the perfusion parameters and the cognitive scores, were also evaluated. Results: Brain perfusion parameters improved significantly in both gray matter (predominantly due to cerebral blood flow within the anterior circulation, p < 0.01) and white matter (predominantly due to cerebral blood volume within the semiovale centrum, p < 0.001). We revealed that the pattern of improvement in perfusion in white matter differed from the pattern of improvement in perfusion in gray matter. Significant correlations were revealed between the Suzuki stage before surgery and the perfusion parameters within the posterior cerebral artery circulation (adjusted p < 0.05). There were also significant correlations between cognitive scores and brain perfusion parameters in gray matter and white matter (adjusted p < 0.05). Conclusions: The perfusion parameters of gray matter and white matter in the brain improve differently after bypass surgery in patients with MMA. Different hemodynamics within these compartments could explain this.

Anesthetic Considerations of Organ Procurement After Brain and Cardiac Death: A Narrative Review.

Organ donation procedures have become more frequent in the US as the need for transplants is increasing. Defining the anesthesiologist's role in organ donations after brain and cardiac death is important, as is understanding its ethics and practical physiologic and perioperative implications. Despite this, there are few papers specifically addressing the anesthetic management of organ donors. This review summarizes the preoperative, intraoperative, and postmortem considerations for the anesthesiologist involved in organ donation after either brain or cardiac death.A search of the published literature was performed using PubMed, Excerpta Medica dataBASE (EMBASE), and Google Scholar in March of 2022 for articles addressing anesthetic considerations of organ procurement surgeries after brain and cardiac death. This review demonstrates that anesthesiologists play a significant role in the organ procurement process. Their role in the perioperative management of the donor may affect the outcomes of organ transplantation. The gap between the number of organs harvested and the number of patients awaiting organ transplantation remains high despite continued efforts to increase the number of available organs. Perioperative management of organ donors aims at counteracting the associated unique physiologic derangements and targets optimization of oxygenation of the organs intended for procurement. Optimizing care after death can help ensure the viability of organs and the best outcomes for recipients. As organ donation after cardiac death (DCD) becomes more frequent in the US, anesthesiologists should be aware of the DCD classifications of donors and emerging novel perfusion techniques.

How to Preserve Steatotic Liver Grafts for Transplantation.

Liver allograft steatosis is a significant risk factor for postoperative graft dysfunction and has been associated with inferior patient and graft survival, particularly in the case of moderate or severe macrovesicular steatosis. In recent years, the increasing incidence of obesity and fatty liver disease in the population has led to a higher proportion of steatotic liver grafts being used for transplantation, making the optimization of their preservation an urgent necessity. This review discusses the mechanisms behind the increased susceptibility of fatty livers to ischemia-reperfusion injury and provides an overview of the available strategies to improve their utilization for transplantation, with a focus on preclinical and clinical evidence supporting donor interventions, novel preservation solutions, and machine perfusion techniques.

Machine perfusion techniques for liver transplantation - A meta-analysis of the first seven randomized-controlled trials

Machine perfusion is increasingly being tested in clinical transplantation. Despite this, the number of large prospective clinical trials remains limited. The aim of this study was to compare the impact of machine perfusion vs. static cold storage (SCS) on outcomes after liver transplantation. A systematic search of MEDLINE, EMBASE, CINAHL and the Cochrane Central Register of Controlled Trials (CENTRAL) was conducted to identify randomized-controlled trials (RCTs) comparing "post-transplant" outcomes following machine perfusion vs. SCS. Data were pooled using random effect models. Risk ratios (RRs) were calculated for relevant outcomes. The quality of evidence was rated using the GRADE-framework. Seven RCTs were identified (four on hypothermic oxygenated [HOPE] and three on normothermic machine perfusion [NMP]), including a total number of 1,017 patients. Both techniques were associated with significantly lower rates of early allograft dysfunction (NMP: n= 41/282, SCS: n= 74/253, RR 0.50, 95% CI 0.30-0.86, p=0.01, I2= 39%; HOPE: n= 45/241, SCS: n= 97/241, RR 0.48, 95% CI 0.35-0.65, p<0.00001, I2= 5%). The HOPE approach led to a significant reduction in major complications (Clavien Grade ≥IIIb; HOPE: n= 90/241; SCS: n= 117/241, RR 0.76, 95% CI 0.63-0.93, p=0.006, I2= 0%), "re-transplantation" (HOPE: n= 1/163; SCS: n= 11/163; RR 0.21, 95% CI 0.04-0.96, p=0.04; I2= 0%) and graft loss (HOPE: n= 7/163; SCS: n= 19/163; RR 0.40, 95% CI 0.17-0.95, p=0.04; I2= 0%). Both perfusion techniques were found to 'likely' reduce overall biliary complications and non-anastomotic strictures. Although this study provides the highest current evidence on the role of machine perfusion, outcomes remain limited to a 1-year follow-up after liver transplantation. Comparative RCTs and large real-world cohort studies with longer follow-up are required to enhance the robustness of the data further, thereby supporting the introduction of perfusion technologies into routine clinical practice. CRD42022355252. For a decade, two dynamic perfusion concepts have increasingly been tested in several transplant centres worldwide. We undertook the first systematic review and meta-analysis and identified seven published RCTs, including 1,017 patients, evaluating the effect of machine perfusion (hypothermic and normothermic perfusion techniques) compared to static cold storage in liver transplantation. Both perfusion techniques were associated with lower rates of early allograft dysfunction in the first week after liver transplantation. Hypothermic oxygenated perfusion led to a reduction in major complications, lower "re-transplantation" rates and better graft survival. Both perfusion strategies were found to 'likely' reduce overall biliary complications and non-anastomotic biliary strictures. This study provides the highest current evidence on the role of machine perfusion. Outcomes remain limited to a 1-year post-transplant follow-up. Larger cohort studies with longer follow-up and clinical trials comparing the perfusion techniques are required. This is especially relevant to provide clarity and optimise implementation processes further to support the commissioning of this technology worldwide.

Outcomes of Kidney Perfusion Techniques in Transplantation from Deceased Donors: A Systematic Review and Meta-Analysis.

The high demand for organs in kidney transplantation and the expansion of the donor pool have led to the widespread implementation of machine perfusion technologies. In this study, we aim to provide an up-to-date systematic review of the developments in this expanding field over the past 10 years, with the aim of answering the question: "which perfusion technique is the most promising technique in kidney transplantation?" A systematic review of the literature related to machine perfusion in kidney transplantation was performed. The primary outcome measure was delayed graft function (DGF), and secondary outcomes included rates of rejection, graft survival, and patient survival rates after 1 year. Based on the available data, a meta-analysis was performed. The results were compared with data from static cold storage, which is still the standard of care in many centers worldwide. A total of 56 studies conducted in humans were included, and 43 studies reported outcomes of hypothermic machine perfusion (HMP), with a DGF rate of 26.4%. A meta-analysis of 16 studies showed significantly lower DGF rates in the HMP group compared to those of static cold storage (SCS). Five studies reported outcomes of hypothermic machine perfusion + O2, with an overall DGF rate of 29.7%. Two studies explored normothermic machine perfusion (NMP). These were pilot studies, designed to assess the feasibility of this perfusion approach in the clinical setting. Six studies reported outcomes of normothermic regional perfusion (NRP). The overall incidence of DGF was 71.5%, as it was primarily used in uncontrolled DCD (Maastricht category I-II). Three studies comparing NRP to in situ cold perfusion showed a significantly lower rate of DGF with NRP. The systematic review and meta-analysis provide evidence that dynamic preservation strategies can improve outcomes following kidney transplantation. More recent approaches such as normothermic machine perfusion and hypothermic machine perfusion + O2 do show promising results but need further results from the clinical setting. This study shows that the implementation of perfusion strategies could play an important role in safely expanding the donor pool.

End-ischemic hypothermic oxygenated perfusion for extended criteria donors in liver transplantation: a multicenter, randomized controlled trial—HOPExt

BackgroundGiven the scarce donor supply, an increasing number of so-called marginal or extended criteria donor (ECD) organs are used for liver transplantation. These ECD liver grafts are however known to be associated with a higher rate of early allograft dysfunction and primary non-function because of a greater vulnerability to ischemia–reperfusion injury. The end-ischemic hypothermic oxygenated machine perfusion (HOPE) technique may improve outcomes of liver transplantation with ECD grafts by decreasing reperfusion injury.MethodsHOPExt trial is a comparative open-label, multicenter, national, prospective, randomized, controlled study, in two parallel groups, using static cold storage, the gold standard procedure, as control. The trial will enroll adult patients on the transplant waiting list for liver failure or liver cirrhosis and/or liver malignancy requiring liver transplantation and receiving an ECD liver graft from a brain-dead donor. In the experimental group, ECD liver grafts will first undergo a classical static cold (4 °C) storage followed by a hypothermic oxygenated perfusion (HOPE) for a period of 1 to 4 h. The control group will consist of the classic static cold storage which is the gold standard procedure in liver transplantation. The primary objective of this trial is to study the efficacy of HOPE used before transplantation of ECD liver grafts from brain-dead donors in reducing postoperative early allograft dysfunction within the first 7 postoperative days compared to simple cold static storage.DiscussionWe present in this protocol all study procedures in regard to the achievement of the HOPExt trial, to prevent biased analysis of trial outcomes and improve the transparency of the trial results. Enrollment of patients in the HOPExt trial has started on September 10, 2019, and is ongoing.Trial registrationClinicalTrials.gov NCT03929523. Registered on April 29, 2019, before the start of inclusion.

Sevoflurane Improves Ventricular Conduction by Exosomes Derived from Rat Cardiac Fibroblasts After Hypothermic Global Ischemia-Reperfusion Injury.

This study investigated the effect of exosomes derived from sevoflurane-treated cardiac fibroblasts (Sev-CFs-Exo) on reperfusion arrhythmias (RA), ventricular conduction, and myocardial ischemia-reperfusion injury (MIRI). Primary cardiac fibroblasts (CFs) were isolated from the hearts of neonatal rats and identified by morphology and immunofluorescence. Exosomes were isolated from CFs at passages 2-3 after they had been treated with 2.5% sevoflurane for an hour and cultivated for 24-48 hours. The control group was CFs that did not receive any treatment. The hypothermic global ischemia-reperfusion injury model was established using the Langendorff perfusion technique following injection with exosomes through the caudal vein. Multi-electrode array (MEA) mapping was used to investigate the changes in RA and ventricular conduction in isolated hearts. Western blots and immunofluorescence were used to examine the relative expression and location of connexin 43 (Cx43). In addition, the MIRI was evaluated with triphenyl tetrazolium chloride and Hematoxylin-Eosin staining. The primary CFs had a variety of morphologies, no spontaneous pulsation, and were vimentin-positive, which confirmed their successful isolation. Sev-CFs-Exo increased the heart rate (HR) at reperfusion for 15 minutes (T2) and 30 minutes (T3) and lowered the score and duration of RA and the time for restoration of heartbeat in reperfusion. Meanwhile, Sev-CFs-Exo increased conduction velocity (CV), decreased absolute inhomogeneity (P5-95) and inhomogeneity index (P5-95/P50) at T2 and T3, as well as promoted the recovery of HR, CV, P5-95 and P5-95/P50 after hypothermic global ischemia-reperfusion injury. Furthermore, Sev-CFs-Exo raised expression and reduced lateralization of Cx43, and improved myocardial infarct sizes and cellular necrosis. However, while cardiac fibroblast-derived exosomes (CFs-Exo) showed similar cardioprotective effects, the outcomes were not as significant. Sevoflurane reduces the risk of RA and improves ventricular conduction and MIRI by CFs-Exo, and this may be driven by the expression and location of Cx43.

61 - Advanced laparoscopic surgical training using the Goyri-O’Neill perfusion technique of cadaveric embalming

61 - Advanced laparoscopic surgical training using the Goyri-O’Neill perfusion technique of cadaveric embalming

The Non-Invasive Diagnosis of Chronic Coronary Syndrome: A Focus on Stress Computed Tomography Perfusion and Stress Cardiac Magnetic Resonance.

Coronary artery disease is still a major cause of death and morbidity worldwide. In the setting of chronic coronary disease, demonstration of inducible ischemia is mandatory to address treatment. Consequently, scientific and technological efforts were made in response to the request for non-invasive diagnostic tools with better sensitivity and specificity. To date, clinicians have at their disposal a wide range of stress-imaging techniques. Among others, stress cardiac magnetic resonance (S-CMR) and computed tomography perfusion (CTP) techniques both demonstrated their diagnostic efficacy and prognostic value in clinical trials when compared to other non-invasive ischemia-assessing techniques and invasive fractional flow reserve measurement techniques. Standardized protocols for both S-CMR and CTP usually imply the administration of vasodilator agents to induce hyperemia and contrast agents to depict perfusion defects. However, both methods have their own limitations, meaning that optimizing their performance still requires a patient-tailored approach. This review focuses on the characteristics, drawbacks, and future perspectives of these two techniques.

Conventional and Advanced Magnetic Resonance Imaging Assessment of Non-Enhancing Peritumoral Area in Brain Tumor.

The non-enhancing peritumoral area (NEPA) is defined as the hyperintense region in T2-weighted and fluid-attenuated inversion recovery (FLAIR) images surrounding a brain tumor. The NEPA corresponds to different pathological processes, including vasogenic edema and infiltrative edema. The analysis of the NEPA with conventional and advanced magnetic resonance imaging (MRI) was proposed in the differential diagnosis of solid brain tumors, showing higher accuracy than MRI evaluation of the enhancing part of the tumor. In particular, MRI assessment of the NEPA was demonstrated to be a promising tool for distinguishing high-grade gliomas from primary lymphoma and brain metastases. Additionally, the MRI characteristics of the NEPA were found to correlate with prognosis and treatment response. The purpose of this narrative review was to describe MRI features of the NEPA obtained with conventional and advanced MRI techniques to better understand their potential in identifying the different characteristics of high-grade gliomas, primary lymphoma and brain metastases and in predicting clinical outcome and response to surgery and chemo-irradiation. Diffusion and perfusion techniques, such as diffusion tensor imaging (DTI), diffusional kurtosis imaging (DKI), dynamic susceptibility contrast-enhanced (DSC) perfusion imaging, dynamic contrast-enhanced (DCE) perfusion imaging, arterial spin labeling (ASL), spectroscopy and amide proton transfer (APT), were the advanced MRI procedures we reviewed.

Cerebral Perfusion and Neuromonitoring during Complex Aortic Arch Surgery: A Narrative Review.

Complex ascending and aortic arch surgery requires the implementation of different cerebral protection strategies to avoid or limit the probability of intraoperative brain damage during circulatory arrest. The etiology of the damage is multifactorial, involving cerebral embolism, hypoperfusion, hypoxia and inflammatory response. These protective strategies include the use of deep or moderate hypothermia to reduce the cerebral oxygen consumption, allowing the toleration of a variable period of absence of cerebral blood flow, and the use of different cerebral perfusion techniques, both anterograde and retrograde, on top of hypothermia, to avoid any period of intraoperative brain ischemia. In this narrative review, the pathophysiology of cerebral damage during aortic surgery is described. The different options for brain protection, including hypothermia, anterograde or retrograde cerebral perfusion, are also analyzed, with a critical review of the advantages and limitations under a technical point of view. Finally, the current systems of intraoperative brain monitoring are also discussed.

The Current Role and Future Applications of Machine Perfusion in Liver Transplantation.

The relative paucity of donor livers suitable for transplantation has sparked innovations to preserve and recondition organs to expand the pool of transplantable organs. Currently, machine perfusion techniques have led to the improvement of the quality of marginal livers and to prolonged cold ischemia time and have allowed for the prediction of graft function through the analysis of the organ during perfusion, improving the rate of organ use. In the future, the implementation of organ modulation might expand the scope of machine perfusion beyond its current usage. The aim of this review was to provide an overview of the current clinical use of machine perfusion devices in liver transplantation and to provide a perspective for future clinical use, including therapeutic interventions in perfused donor liver grafts.

Whole-body perfusion improves intraoperative transfusions in neonatal aortic arch surgery.

Whole body perfusion is the combination of lower body perfusion and antegrade cerebral perfusion. This perfusion technique is used in some centres when performing aortic arch reconstruction surgery in neonates and infants. Several studies have shown intra- and postoperative benefits of this technique. However, no studies have analysed the impact it may have on the transfusion of blood products and coagulation factors. We retrospectively analysed 65 consecutive neonates and infants who underwent aortic arch reconstruction surgery from January 2014 to July 2020. Patients operated from 2014-2017 underwent surgery with antegrade cerebral perfusion; in patients who underwent surgery from 2017-2020 a whole-body perfusion strategy was used. Demographic, intra- and postoperative parameters were compared as well as intraoperative blood-product and coagulation factor transfusions, chest-tube output in the first 24-hours and postoperative bleeding complications. Both groups required intraoperative transfusion of red blood cells, fresh frozen plasma, and platelets, as well as substitution of coagulation factors. The amount of transfused volumes of red blood cells, fresh frozen plasma, and platelets (p-values 0.01, <0.01, and <0.01) and intraoperative transfusions of fibrinogen and von Willebrand factor were significantly lower in the whole-body perfusion group (p-value 0.04 and <0.01). A whole-body perfusion strategy may lead to fewer intraoperative blood product and coagulation factor transfusions when compared to antegrade cerebral perfusion alone in neonates and infants undergoing complex aortic arch reconstruction surgery.

Absence of Bcl11b in murine heart leads to mitochondrial dysfunction and cardiomyocyte death

B cell lymphoma 11b (Bcl11b/Ctip2) is a zinc finger transcriptional factor involved in a number of physiological processes, including cardiac hypertrophy. In humans, genome-wide association studies show that a common genetic variation in the 3’ region of Bcl11b gene is associated with higher risk of aortic stiffness and increased rate of cardiovascular disease. In mice, Bcl11b invalidation specifically in cardiomyocytes leads to cardiac malfunction, fibrosis augmentation and cell death. Our specific aims are: To investigate the signalling pathways related to cardiac cell death and to assess the sarcomere structure of cardiomyocytes in the absence of Bcl11b. The experiments were conducted using cardiac specific Bcl11b knock-out mice induced by tamoxifen administration 3 and 7 days after the invalidation, cardiac tissues were collected to perform RNA sequencing and subsequently to analyse related molecular pathways using bioinformatic tools. In parallel, cardiomyocytes were purified and isolated by conducting Langendorff perfusion technique to have a better insight into the impact of Bcl11b. A simplified mathematical model, Fourier transform analysis was used to assess sarcomeric length following Bcl11b invalidation in cardiomyocytes. Based on the RNA sequencing results, Bcl11b invalidation has an impact on the regulation of over 2000 genes. Among them, genes related to cell death and mitochondrial functions are the most affected regarding the enrichment scores. Interestingly, a considerable number of genes fall into the “Cuproptosis” pathway, a newly identified, non-apoptotic cell death mechanism. The oxygen consumption of mitochondria was also measured using the Seahorse assay. Bcl11b deletion leads to the decrease in basal level of mitochondrial respiration with no effect on the maximum respiratory capacity. Finally, adult cardiomyocytes in the mutant groups showed a moderate hypertrophy (15% bigger than the control group). However, Fourier transform analysis exhibited stability in the average sarcomere length of these cells. The obtained data suggest that cardiac specific invalidation of Bcl11b induces mitochondrial dysfunction and possibly cell death through the “Cuproptosis” pathway.

Studies of the retinal microcirculation using human donor eyes and high-resolution clinical imaging: Insights gained to guide future research in diabetic retinopathy.

The microcirculation plays a key role in delivering oxygen to and removing metabolic wastes from energy-intensive retinal neurons. Microvascular changes are a hallmark feature of diabetic retinopathy (DR), a major cause of irreversible vision loss globally. Early investigators have performed landmark studies characterising the pathologic manifestations of DR. Previous works have collectively informed us of the clinical stages of DR and the retinal manifestations associated with devastating vision loss. Since these reports, major advancements in histologic techniques coupled with three-dimensional image processing has facilitated a deeper understanding of the structural characteristics in the healthy and diseased retinal circulation. Furthermore, breakthroughs in high-resolution retinal imaging have facilitated clinical translation of histologic knowledge to detect and monitor progression of microcirculatory disturbances with greater precision. Isolated perfusion techniques have been applied to human donor eyes to further our understanding of the cytoarchitectural characteristics of the normal human retinal circulation as well as provide novel insights into the pathophysiology of DR. Histology has been used to validate emerging in vivo retinal imaging techniques such as optical coherence tomography angiography. This report provides an overview of our research on the human retinal microcirculation in the context of the current ophthalmic literature. We commence by proposing a standardised histologic lexicon for characterising the human retinal microcirculation and subsequently discuss the pathophysiologic mechanisms underlying key manifestations of DR, with a focus on microaneurysms and retinal ischaemia. The advantages and limitations of current retinal imaging modalities as determined using histologic validation are also presented. We conclude with an overview of the implications of our research and provide a perspective on future directions in DR research.

Intravoxel incoherent motion for differentiating residual/recurrent tumor from post-treatment change in patients with high-grade glioma.

To investigate the diagnostic value of f derived from IVIM technique and to correlate it with rCBV derived from DSC for the differentiation of residual/recurrent tumor from post-treatment change in patients with high-grade glioma. Patients who underwent MR imaging with IVIM and DSC studies for evaluation of high-grade glioma after standard treatment were enrolled in this retrospective study. For qualitative analysis, the f and rCBV maps were interpreted as hypoperfused or hyperperfused in each parameter. Quantitative analysis was performed using ROI analysis in f and rCBV parameters. The lesions were divided into residual/recurrent tumor and post-treatment change groups. Nineteen patients with high-grade glioma were included. In qualitative analysis, the f-map shows higher sensitivity (100.0%) than rCBV map (92.3%), while the rCBV map shows higher specificity (100.0%) than the f-map (83.3%). In quantitative analysis, the optimal cutoff values of 1.19 for f and 1.06 for rCBV are shown to provide high diagnostic value with high sensitivity (91.7%) for both parameters but slightly higher specificity of rCBV (85.7%) than f (71.4%). The correlation between f and rCBV was good with ICC of 0.810. The f value measured by IVIM technique, non-contrast perfusion technique, has high diagnostic performance and potential to be an alternative method to CBV measured by DSC for differentiation between residual/recurrent tumor and post-treatment change in patients with high-grade glioma.

Perfusion techniques for thoracoabdominal aortic aneurysms

ZusammenfassungDie operative Behandlung thorakoabdomineller Aortenaneurysmen (TAAA) ist eine komplexe Prozedur und erfordert eine entsprechende Planung. Die TAAA werden entsprechend der Crawford-Klassifikation (Typen I bis V) eingeteilt. Typ-II-TAAA erfordern den ausgedehntesten Eingriff und weisen dementsprechend die höchste postoperative Morbidität und Mortalität auf. Die Perfusionsstrategie der Viszeralorgane und des Rückenmarks ist bei der operativen Versorgung der TAAA von zentraler Bedeutung. Die distale arterielle Perfusion, die selektive viszerale Perfusion und die additiven protektiven Maßnahmen mit Liquordrainage und hämodynamischem Management zur möglichst frühzeitigen Etablierung eines pulsatilen Flusses spielen dabei eine wesentliche Rolle. Die Techniken der extrakorporalen Zirkulation mit Herz-Lungen-Maschine oder Linksherzbypass werden mit ihren Vor- und Nachteilen diskutiert. Die Möglichkeiten zur viszeralen Organperfusion werden vorgestellt.

Construction of PLGA Porous Microsphere-Based Artificial Pancreatic Islets Assisted by the Cell Centrifugation Perfusion Technique.

Pancreatic islet transplantation is a promising treatment that could potentially reverse diabetes, but its clinical applicability is severely limited by a shortage of organ donors. Various cell loading approaches using polymeric porous microspheres (PMs) have been developed for tissue regeneration; however, PM-based multicellular artificial pancreatic islets' construction has been scarcely reported. In this study, MIN6 (a mouse insulinoma cell line) and MS1 (a mouse pancreatic islet endothelial cell line) cells were seeded into poly(lactic-co-glycolic acid) (PLGA) PMs via an upgraded centrifugation-based cell perfusion seeding technique invented and patented by our group. Cell morphology, distribution, viability, migration, and proliferation were all evaluated. Results from glucose-stimulated insulin secretion (GSIS) assay and RNA-seq analysis suggested that MIN6 and MS1-loaded PLGA PMs exhibited better glucose responsiveness, which is partly attributable to vascular formation during PM-dependent islet construction. The present study suggests that the PLGA PM-based artificial pancreatic islets may provide an alternative strategy for the potential treatment of diabetes in the future.