scholarly journals Multimodal Functional Imaging for Cancer/Tumor Microenvironments Based on MRI, EPRI, and PET

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1614
Author(s):  
Ken-ichiro Matsumoto ◽  
James B. Mitchell ◽  
Murali C. Krishna
Keyword(s):  
Radiation Therapy ◽  
Functional Imaging ◽  
Imaging Techniques ◽  
Biological Effects ◽  
Tumor Hypoxia ◽  
Redox Status ◽  
Blood Oxygen Level Dependent ◽  
Oxygen Level ◽  
Cancer Tumor

Radiation therapy is one of the main modalities to treat cancer/tumor. The response to radiation therapy, however, can be influenced by physiological and/or pathological conditions in the target tissues, especially by the low partial oxygen pressure and altered redox status in cancer/tumor tissues. Visualizing such cancer/tumor patho-physiological microenvironment would be a useful not only for planning radiotherapy but also to detect cancer/tumor in an earlier stage. Tumor hypoxia could be sensed by positron emission tomography (PET), electron paramagnetic resonance (EPR) oxygen mapping, and in vivo dynamic nuclear polarization (DNP) MRI. Tissue oxygenation could be visualized on a real-time basis by blood oxygen level dependent (BOLD) and/or tissue oxygen level dependent (TOLD) MRI signal. EPR imaging (EPRI) and/or T1-weighted MRI techniques can visualize tissue redox status non-invasively based on paramagnetic and diamagnetic conversions of nitroxyl radical contrast agent. 13C-DNP MRI can visualize glycometabolism of tumor/cancer tissues. Accurate co-registration of those multimodal images could make mechanisms of drug and/or relation of resulted biological effects clear. A multimodal instrument, such as PET-MRI, may have another possibility to link multiple functions. Functional imaging techniques individually developed to date have been converged on the concept of theranostics.

scholarly journals Role of MRI-Based Functional Imaging in Improving the Therapeutic Index of Radiotherapy in Cancer Treatment

2021 ◽  
Vol 11 ◽  
Author(s):  
Mei Li ◽  
Qin Zhang ◽  
Kaixuan Yang
Keyword(s):  
Radiation Therapy ◽  
Functional Imaging ◽  
Imaging Techniques ◽  
Organs At Risk ◽  
Therapeutic Index ◽  
Target Volume ◽  
Local Control Rate ◽  
Biological Information ◽  
Radiation Technology ◽  
Target Delineation

Advances in radiation technology, such as intensity-modulated radiation therapy (IMRT), have largely enabled a biological dose escalation of the target volume (TV) and reduce the dose to adjacent tissues or organs at risk (OARs). However, the risk of radiation-induced injury increases as more radiation dose utilized during radiation therapy (RT), which predominantly limits further increases in TV dose distribution and reduces the local control rate. Thus, the accurate target delineation is crucial. Recently, technological improvements for precise target delineation have obtained more attention in the field of RT. The addition of functional imaging to RT can provide a more accurate anatomy of the tumor and normal tissues (such as location and size), along with biological information that aids to optimize the therapeutic index (TI) of RT. In this review, we discuss the application of some common MRI-based functional imaging techniques in clinical practice. In addition, we summarize the main challenges and prospects of these imaging technologies, expecting more inspiring developments and more productive research paths in the near future.

Hemoglobin microbubbles for in vivo blood oxygen level dependent imaging: Boldly moving beyond MRI

2021 ◽  
Vol 150 (4) ◽  
pp. A27-A27
Author(s):  
Sugandha Chaudhary ◽  
Nasrin Akter ◽  
Akshay Rajeev ◽  
Misun Hwang ◽  
Shashank Sirsi
Keyword(s):  
Blood Oxygen Level Dependent ◽  
Blood Oxygen ◽  
Oxygen Level ◽  
Blood Oxygen Level

scholarly journals Antioxidant and Antimicrobial Activity of Cleome droserifolia (Forssk.) Del. and Its Biological Effects on Redox Status, Immunity and Gut Microflora

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1929
Author(s):  
Nesrein M. Hashem ◽  
Mohamed G. Shehata
Keyword(s):  
Phenolic Compounds ◽  
Blood Plasma ◽  
Methanolic Extract ◽  
Biological Effects ◽  
Redox Status ◽  
Biological Evaluation ◽  
Biologically Active ◽  
Lactobacillus Species

This study aimed to investigate the antioxidant, antimicrobial, and immunomodulatory activities of a Cleome droserifolia (Forssk.) Del. (Cd) shoot methanolic extracts considering the biological activity of its phytogenic compounds. For this purpose, the Cd phenolic compounds were detected, and an in vitro evaluation of the antioxidant and antimicrobial activities of the Cd extract was performed. For a biological evaluation, 30 v-line rabbits were randomly distributed into three groups with treatments including: a basal diet without Cd shoots powder supplement (C group) or supplemented with 1.25- (Cdl group) or 2.5 (Cdh group)-mg Cd/kg dry matter (DM). The Cd extract showed a linear scavenging activity for 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), with the maximal activity observed at a concentration of 1 mg/mL. A total of 16 phenolic compounds were identified by reverse-phase high-performance liquid chromatography (RP-HPLC) in the Cd methanolic extract, among which benzoic acid, rutin, ellagic acid, naringenin, and o-coumaric acid were the major compounds. The methanolic extract of Cd showed inhibitory actions against microbial pathogen species. The in vivo study showed that the two concentrations of Cd significantly improved the redox status of the blood plasma and lysozyme activity. Treatment with Cdh significantly decreased the levels of interleukin-β1 in the blood plasma compared with the control. Moreover, the two concentrations of Cd significantly increased the counts of intestinal and cecal yeast and Lactobacillus species and decreased the Salmonella and Coliform species compared with the control. The aerial parts of the Cd shrub had strong antioxidant, antimicrobial, and immunomodulatory activities, which can improve the overall health status and seem to be related to its impressive range of biologically active phenolic compounds.

Tumor hypoxia as a mechanism of resistance to bevacizumab in a murine model.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e13111-e13111 ◽  
Author(s):  
Linda Heijmen ◽  
Otto C. Boerman ◽  
Cornelis J. A. Punt ◽  
E. Ter Voert ◽  
Wim J.G. Oyen ◽  
...  
Keyword(s):  
Imaging Techniques ◽  
Tumor Hypoxia ◽  
Therapy Resistance ◽  
Control Group ◽  
Vascular Density ◽  
Hypoxic Fraction ◽  
Induced Changes ◽  
T2 Mri ◽  
Over Time

e13111 Background: Despite the promise of preclinical and early phase clinical studies, the efficacy of bevacizumab in solid tumors is more limited than expected. One of the presumed reasons is the induction of tumor hypoxia by the anti-angiogenic effects of bevacizumab, leading to therapy resistance. The aim of this study was to assess the effect of bevacizumab on tumor hypoxia in vivo in a colorectal cancer model, using functional imaging techniques. Methods: Nude mice with s.c. LS174T colon carcinoma xenografts (0.05 - 0.3 cm3) were treated with bevacizumab (5 mg/kg; 2/wk, i.p.) or saline as a control. To assess tumor hypoxia in vivo 18F-MISO-PET microPET or T2*-MRI images were acquired of separate groups of mice (n=5) before treatment and at day 2, 6 and 10 days after start of treatment. Tumors were harvested directly after imaging to microscopically assess the hypoxic fraction (pimonidazole staining) and vascular density (9F1 staining). Results: Linear regression analyses showed that FMISO uptake increased significantly more over time in the control group than in the bevacizumab group (beta -0.44, p=0.02), indicating that bevacizumab reduced the inherent increase in tumor hypoxia over time. T2* time increased significantly less in the bevacizumab group (beta -0.45, p=0.01), indicating a higher deoxyhemoglobine concentration, which might indicate a higher perfusion of the tumor and thus less hypoxia. The hypoxic fraction did not change over time and no difference was observed between the tumors in the treated and the control group. Vessel density significantly decreased over time in the bevacizumab group (beta -0.25, p=0.05), while the hypoxic fraction remained unchanged in the control group. Conclusions: The bevacizumab-induced changes in the tumor were most prominent at 10 days after treatment initiation, implying a build-up effect of repeated bevacizumab administration. The treatment induced changes could be detected with both T2*-MRI as well as with FMISO microPET. Bevacizumab did not induce tumor hypoxia, despite the observed decrease in vascular density. Therefore, induction of tumor hypoxia as a resistance mechanism to bevacizumab treatment seems unlikely.

scholarly journals Emerging Functional Imaging Biomarkers of Tumour Responses to Radiotherapy

Cancers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 131 ◽  
Author(s):  
Alan Campbell ◽  
Laura M. Davis ◽  
Sophie K. Wilkinson ◽  
Richard L. Hesketh
Keyword(s):  
Functional Imaging ◽  
Imaging Techniques ◽  
Biological Effects ◽  
Treatment Options ◽  
Early Response ◽  
Whole Body ◽  
Imaging Biomarkers ◽  
Biological Processes ◽  
Tumour Burden ◽  
Non Invasive

Tumour responses to radiotherapy are currently primarily assessed by changes in size. Imaging permits non-invasive, whole-body assessment of tumour burden and guides treatment options for most tumours. However, in most tumours, changes in size are slow to manifest and can sometimes be difficult to interpret or misleading, potentially leading to prolonged durations of ineffective treatment and delays in changing therapy. Functional imaging techniques that monitor biological processes have the potential to detect tumour responses to treatment earlier and refine treatment options based on tumour biology rather than solely on size and staging. By considering the biological effects of radiotherapy, this review focusses on emerging functional imaging techniques with the potential to augment morphological imaging and serve as biomarkers of early response to radiotherapy.

scholarly journals Functional Imaging of the Ocular Fundus Using an 8-Band Retinal Multispectral Imaging System

Instruments ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 12
Author(s):  
Emanuel R. de Carvalho ◽  
Richelle J. M. Hoveling ◽  
Cornelis J. F. van Noorden ◽  
Reinier O. Schlingemann ◽  
Maurice C. G. Aalders
Keyword(s):  
Oxygen Saturation ◽  
Functional Imaging ◽  
Multispectral Imaging ◽  
Imaging System ◽  
Imaging Techniques ◽  
Incident Light ◽  
Contrast Imaging ◽  
Blood Oxygen Saturation ◽  
Full Scan

Application of functional imaging in ophthalmology requires efficient imaging techniques that can detect and quantify chromophores to visualise processes in vivo. The aim of the present study was to develop and evaluate a fast and affordable imaging system. We describe an eight-band retinal multispectral imaging (MSI) system and compare it with a hyperspectral imaging (HSI) device. Determination of blood oxygen saturation was studied as proof of principle. Reflectance of incident light is measured as 1/absorbance at different wavelengths between 440 nm and 580 nm. Both devices have incorporated optical bandpass filters in a mydriatic fundus camera. The MSI system scans the retina at eight pre-defined wavelengths specific for the spectrum of haemoglobin. The HSI system acquires a full scan from 480 to 720 nm in 5 nm steps. A simple assessment of the ratio between the absorbance peaks of oxygenated haemoglobin (HbO2) and reduced haemoglobin (HbR) was not suitable for generating validated oxygenation maps of the retina. However, a correction algorithm that compares the measured reflectance with reflectance spectra of fully oxygenated and fully deoxygenated blood allowed our MSI setup to estimate relative oxygen saturation at higher levels, but underestimated relative oxygen saturation at lower levels. The MSI device generated better quality images than the HSI device. It allows customisation with filter sets optimised for other chromophores of interest, and augmented with extrinsic contrast imaging agents, it has the potential for a wider range of ophthalmic molecular imaging applications.

Advances in the Role of Neuroimaging to Monitor Disease Progression in Parkinson’s Disease

2011 ◽  
Vol 6 (3) ◽  
pp. 161
Author(s):  
Pankaj A Agarwal ◽  
A Jon Stoessl ◽  
◽  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Disease Progression ◽  
Functional Imaging ◽  
Single Photon ◽  
Imaging Techniques ◽  
Photon Emission ◽  
Negative Exponential ◽  
Radiotracer Imaging

Since structural imaging has generally failed to demonstrate consistent abnormalities in Parkinson’s disease (PD), from an imaging perspective, the diagnosis has typically been based upon the demonstration of impaired striatal dopamine (DA) function. Radiotracer imaging techniques such as positron emission tomography (PET) and single photon emission computerised tomography (SPECT) allow thein vivoassessment of nigrostriatal DA function as well as regional cerebral blood flow, glucose metabolism, and functional connectivity, and changes in these measures have been used to infer disease progression. Pre-synaptic radiotracer imaging (RTI) has shown that striatal dopaminergic hypofunction follows a negative exponential pattern with the fastest rate of decline in early disease. Moreover, while striatal subregions remain differentially affected throughout the course of disease, with the posterior putamen affected more than anterior structures, the rate of deterioration is similar in all subregions. However, although functional imaging is undoubtedly a very useful tool in the assessment of PD progression, various studies have shown discordance between clinical progression of PD and nigrostriatal degeneration estimated by PET or SPECT. Therefore, considerable caution is warranted in the interpretation of imaging findings. While a potentially invaluable complement in assessing the severity of dopaminergic dysfunction, functional imaging is not a substitute for clinical assessment and other objective measures of PD severity, and cannot be currently considered a biomarker for progression of PD.

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