Interventional cardiac magnetic resonance imaging: current applications, technology readiness level, and future perspectives.

Background: Cardiac magnetic resonance (CMR) provides excellent temporal and spatial resolution, tissue characterization, and flow measurements. This enables major advantages when guiding cardiac invasive procedures compared with X-ray fluoroscopy or ultrasound guidance. However, clinical implementation is limited due to limited availability of technological advancements in magnetic resonance imaging (MRI) compatible equipment.

Enhancing cardiovascular artificial intelligence (AI) research in the Netherlands: CVON-AI consortium.

Background: Machine learning (ML) allows the exploration and progressive improvement of very complex high-dimensional data patterns that can be utilised to optimise specific classification and prediction tasks, outperforming traditional statistical approaches. An enormous acceleration of ready-to-use tools and artificial intelligence (AI) applications, shaped by the emergence, refinement, and application of powerful ML algorithms in several areas of knowledge, is ongoing. Although such progress has begun to permeate the medical sciences and clinical medicine, implementation in cardiovascular medicine and research is still in its infancy.

Feasibility of a low concentration test bolus in CT angiography.

Aim: To investigate the feasibility of using a low-concentration test bolus in abdominal aorta computed tomography (CT) angiography (CTA).

Materials And Methods: In 10 patients referred for CTA of the abdominal aorta with a body mass index (BMI) ≤28 kg/m, a standard test bolus of 10 ml contrast medium (CM; 350 mg iodine/ml) was compared with a low-concentration test bolus (5 ml CM; 350 mg iodine/ml; 1:1 diluted with saline) in terms of time to peak enhancement (tPE) and peak enhancement (PE).

Results: No significant differences were found between the standard and low-concentration test bolus in terms of tPE and PE.

A non-invasive cardiac output measurement as an alternative to the test bolus technique during CT angiography.

Aim: To investigate the association between a non-invasive cardiac output (CO) measurement and the scan delay, as derived from a test bolus injection protocol. The secondary objective was to determine which factors affect the relationship between the CO and scan delay.

Materials And Methods: Fifty-five patients referred for a contrast-enhanced (thorax-)abdomen CT examination were included in this feasibility study.

Reducing contrast medium volume and tube voltage in CT angiography of the pulmonary artery.

Aim: To evaluate image quality after contrast medium (CM) and tube voltage reduction in computed tomography angiography (CTA) of the pulmonary artery.

Materials And Methods: Thirty-three patients referred for CTA of the pulmonary artery for suspected pulmonary embolism were included. Patients were randomly assigned to Protocol I (100 ml of 350 mg iodine/ml iodinated CM; n=16) or Protocol II (50 ml of 350 mg iodine/ml iodinated CM; n=17).

Low-dose CT angiography of the abdominal aorta and reduced contrast medium volume: Assessment of image quality and radiation dose.

Aim: To determine the effect of using 80 kV tube voltage and a reduced amount of contrast medium on the image quality and radiation dose of computed tomography angiography (CTA) of the abdominal aorta.

Materials And Methods: Patients who were referred for a CTA examination of the abdominal aorta were included in this technical efficacy study. Thirty patients were divided randomly into two groups.

Noninvasive Differentiation between Hepatic Steatosis and Steatohepatitis with MR Imaging Enhanced with USPIOs in Patients with Nonalcoholic Fatty Liver Disease: A Proof-of-Concept Study.

Purpose: To (a) study the optimal timing and dosing for ultrasmall superparamagnetic iron oxide particle (USPIO)-enhanced magnetic resonance (MR) imaging of the liver in nonalcoholic fatty liver disease, (b) evaluate whether hepatic USPIO uptake is decreased in nonalcoholic steatohepatitis (NASH), and (c) study the diagnostic accuracy of USPIO-enhanced MR imaging to distinguish between NASH and simple steatosis.

Materials And Methods: This prospective study was approved by the local institutional review board, and informed consent was obtained from all patients. Quantitative R2* MR imaging of the liver was performed at baseline and 72 hours after USPIO administration in patients with biopsy-proven NASH (n = 13), hepatic steatosis without NASH (n = 11), and healthy control subjects (n = 9).

Reduction of contrast medium volume in abdominal aorta CTA: multiphasic injection technique versus a test bolus volume.

Objective: The purpose of this study is to reduce the administered contrast medium volume in abdominal CTA by using a test bolus injection, with the preservation of adequate quantitative and qualitative vessel enhancement.

Study Design: For this technical efficacy study 30 patients, who were referred for a CTA examination of the abdominal aorta, were included. Randomly 15 patients were assigned to undergo a multiphasic injection protocol and received 89 mL of contrast medium (Optiray 350) (protocol I).

Reduced contrast medium in abdominal aorta CTA using a multiphasic injection technique.

Purpose: The purpose of this study was to determine if with a multiphasic injection technique the administered amount of contrast medium for abdominal computerized tomographic angiography (CTA) can be decreased, whilst improving CT image quality.

Materials And Methods: In 30 patients a multiphasic injection method was compared to the standard uniphasic contrast medium injection protocol. Fifteen patients underwent abdominal CTA with a standard uniphasic injection protocol (protocol I) receiving 100mL of a non-ionic radiopaque contrast agent (Ioversol).

1-phenyl-2-decanoylamino-3-morpholino-1-propanol chemosensitizes neuroblastoma cells for taxol and vincristine.

In this study, we show that an inhibitor of glycosphin-golipid biosynthesis, D,L-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP), increases the chemosensitivity of neuroblastoma tumor cells for Taxol and vincristine. At noneffective low doses of Taxol or vincristine, the addition of a noneffective dose of PDMP resulted in 70% cytotoxicity, indicating synergy. Such an effect was not observed for etoposide (VP16).

Leukemia-induced bone marrow depression: effects of gangliosides on erythroid cell production.

Bone marrow depression is a common feature in hematological malignancies or other bone marrow-involving cancers. The mechanism of this hemopoietic suppression resulting in pancytopenia and especially anemia has not been elucidated. Gangliosides can be shed by cancer cells.

Inhibition of hemopoiesis in vitro by neuroblastoma-derived gangliosides.

Hemopoiesis is disturbed in bone marrow-involving cancers like leukemia and neuroblastoma. Shedding of gangliosides by tumor cells may contribute to this tumor-induced bone marrow suppression. We studied in vitro the inhibitory effects of murine neuroblastoma cells (Neuro-2a and C1300) and their gangliosides on hemopoiesis using normal murine hemopoietic progenitor colony-forming assays.

Toxicity of liposomal 3'-5'-O-dipalmitoyl-5-fluoro-2'-deoxyuridine in mice.

Toxicities of 5-fluoro-2'-deoxyuridine (FUdR) and its liposome incorporated dipalmitoyl derivative (FUdR-dipalmitate) to mouse bone marrow, spleen, liver and ileum were compared after treatment for 6 consecutive days. The applied doses of the two formulations, which were shown earlier to have equal antitumor activity in mouse tumor models, were 600 and 2 mumol/kg respectively. When applied in these doses, toxicity to the hemopoietic system, measured as a decreases in progenitor and precursor cells of the erythroid and granuloid/macrophage lineage in bone marrow and spleen, was more severe for FUdR than for liposomal FUdR-dipalmitate.

Interactions of erythropoietin, granulocyte colony-stimulating factor, stem cell factor, and interleukin-11 on murine hematopoiesis during simultaneous administration.

We investigated how in vivo effects of single hematopoietic cytokines change if given in combination for a prolonged time. Mice were treated with every combination of recombinant human (rh) erythropoietin (EPO), rh granulocyte colony-stimulating factor (G-CSF), recombinant rat (rr) stem cell factor (SCF), and rh interleukin (IL)-11 by continuous infusion over 7 days (full factorial design with three dose levels for each cytokine). Burst-forming unit-erythroid (BFU-E), colony-forming unit-erythroid (CFU-E), and colony-forming unit-granulocyte-macrophage (CFU-GM) were determined in bone marrow and spleen, reticulocytes, hematocrit, granulocytes, and thrombocytes in the peripheral blood.

Stem cell factor has contrasting effects in combination with 5-fluorouracil or total-body irradiation on frequencies of different hemopoietic cell subsets and engraftment of transplanted bone marrow.

The effect of stem cell factor (SCF) given at 24, 12 and 2 h before either 5-fluorouracil (5-FU) or total-body irradiation (TBI) was investigated on a range of bone marrow hemopoietic cell subsets that included primitive stem cells capable of long-term repopulation in bone marrow transplant (BMT) recipients. At 24 h after treatment, the femoral content of transient and permanent repopulating stem cell subsets was assessed from the frequency of early- and late-developing cobblestone area-forming cells (CAFCs) growing in stroma-associated cultures. At this time untreated 3 x 10(6) congenically marked donor bone marrow cells (B6-Gpi-Ia-->B6-Gpi-Ib) were transplanted and the level of erythroid engraftment was followed over 1 year.

Capillary electrophoresis system for hemoglobin A1c determinations evaluated.

Hb A1c is the analyte of choice for monitoring metabolic control in patients with diabetes mellitus. Here we present a new analytical technique for measuring Hb A1c, capillary electrophoresis. The Hb A1c determination is not influenced by the labile Hb A1c fraction or by carbamylated or acetylated hemoglobin derivatives.

Mouse strain-dependent changes in frequency and proliferation of hematopoietic stem cells during aging: correlation between lifespan and cycling activity.

We have quantified the frequency and proliferation of five subsets of primitive hematopoietic cells, using the cobblestone area forming cell (CAFC) assay, in marrow of five strains of mice with lifespans ranging from about 500 to 800 days. Stem cell characteristics were determined in young (6 weeks) and old (12 months) mice. We report striking effects of both intrinsic strain lifespan and individual mouse age on stem cell populations.

Concepts of hemopoietic cell amplification. Synergy, redundancy and pleiotropy of cytokines affecting the regulation of erythropoiesis.

Hemopoietic cell amplification in vivo is regulated by various mechanisms which appear to be under control of many hemopoietic growth factors. Quiescent stem cells can be activated into cell cycle, dividing progenitor cells can reduce their cycle time, the differentiation velocity (i.e.

Prophylactic pretreatment of mice with hematopoietic growth factors induces expansion of primitive cell compartments and results in protection against 5-fluorouracil-induced toxicity.

The aim of this study was to expand the primitive and committed hematopoietic cell compartments in vivo in order to confer resistance of the blood cell forming system against the cytotoxic, cell cycle specific drug 5-fluorouracil (5-FU). Possible chemoprotective effects of such a pretreatment could result from increased numbers of hematopoietic cells, present before 5-FU administration. In addition, we hypothesized that an enhanced number of primitive and progenitor calls would result in a reduced cycling activity, ie, 5-FU sensitivity, of these same cells, due to normal physiological feedback loops.

The kinetics of murine hematopoietic stem cells in vivo in response to prolonged increased mature blood cell production induced by granulocyte colony-stimulating factor.

Because of the complexity of appropriate stem cell assays, little information on the in vivo regulation of murine stem cell biology or stemmatopoiesis is available. It is unknown whether and how in vivo the primitive hematopoietic stem cell compartment is affected during a continued increased production of mature blood cells. In this study, we present data showing that prolonged (3 weeks) administration of granulocyte colony-stimulating factor (G-CSF), which is a major regulator of mature granulocyte production, has a substantial impact on both the size and the location of various stem cell subset pools in mice.

In vivo effects of interleukin-11 and stem cell factor in combination with erythropoietin in the regulation of erythropoiesis.

In this study we evaluated the in vivo effects of interleukin-11 (IL-11) and stem cell factor (SCF), in combination with erythropoietin (EPO) on murine erythropoiesis. Mice were treated for 7 d with IL-11. SCF and EPO, each at three dose levels.

Mechanistic options of erythropoietin-stimulated erythropoiesis.

The in vivo mechanism of hematopoietic growth factor-induced cell multiplication is in debate. Several options can be examined: 1) growth factors can reduce the cycling time of their dividing target cells, 2) growth factors can add extra cell divisions within the differentiation pathway, 3) the combination of the first two possibilities, and 4) growth factors can prevent premature cell death (apoptosis) from occurring in the absence of the stimulating factor. We studied these options in vitro and in vivo in the murine erythroid pathway.

Hemotoxicity by prolonged etoposide administration to mice can be prevented by simultaneous growth factor therapy.

In this study, we determined in vivo interactions between hemopoietic growth factors and etoposide (VP-16) to assess whether normal blood cell production could be maintained during chemotherapy if hemopoietic growth factors were simultaneously administered. Groups of mice were treated for 7 consecutive days with four different doses of VP-16 in combination with three different doses of erythropoietin (EPO) or granulocyte colony-stimulating factor (G-CSF). In total, 12 combinations of VP-16 plus EPO and 12 combinations of VP-16 plus G-CSF were thus evaluated.

Effects of continuous stem cell factor administration on normal and erythropoietin-stimulated murine hemopoiesis: experimental results and model analysis.

The aim of this study was to determine how stem cell factor (SCF) modifies hemopoietic cell production. First we determined the effects of a prolonged SCF administration on murine hemopoiesis and analyzed the results by a mathematical simulation model of hemopoiesis in order to explain the data. Subsequently we investigated the effects of simultaneous coadministration of SCF+erythropoietin (Epo), to see how effects of early and late cytokines superimpose.

Mutual inhibition of murine erythropoiesis and granulopoiesis during combined erythropoietin, granulocyte colony-stimulating factor, and stem cell factor administration: in vivo interactions and dose-response surfaces.

We investigated the in vivo effects of erythropoietin (EPO) on granulopoiesis and, conversely, the effect of granulocyte colony-stimulating factor (G-CSF) treatment on erythropoiesis. Recombinant human EPO at four different doses in combination with recombinant human G-CSF also at four different doses was simultaneously administered for 7 days to splenectomized mice. In total, 16 different combinations of growth factors were thus tested.