Sex differences in left-ventricular strain in a murine model of coxsackievirus B3 myocarditis.

Myocarditis is typically caused by viral infections, but most cases are thought to be subclinical. Echocardiography is often used for initial assessment of myocarditis patients but is poor at detecting subtle changes in cardiac dysfunction. Cardiac strain, such as global longitudinal strain (GLS) and global circumferential strain (GCS), represents an increasingly used set of measurements which can detect these subtle changes.

TNF Signaling Is Required for Castration-Induced Vascular Damage Preceding Prostate Cancer Regression.

The mainstay treatment for locally advanced, recurrent, or metastatic prostate cancer (PrCa) is androgen deprivation therapy (ADT). ADT causes prostate cancers to shrink in volume, or regress, by inducing epithelial tumor cell apoptosis. In normal, non-neoplastic murine prostate, androgen deprivation via castration induces prostate gland regression that is dependent on TNF signaling.

Integrating H MRS and deuterium labeled glucose for mapping the dynamics of neural metabolism in humans.

In the technique presented here, dubbed 'qMRS', we quantify the change in H MRS signal following administration of H-labeled glucose. As in recent human DMRS studies, we administer [6,6'-H]-glucose orally to healthy subjects. Since H is not detectable by H MRS, the transfer of the H label from glucose to a downstream metabolite leads to a reduction in the corresponding H MRS resonance of the metabolite, even if the total concentration of both isoforms remains constant.

Photoacoustic Imaging of Tattoo Inks: Phantom and Clinical Evaluation.

Photoacoustic imaging (PAI) is a novel hybrid imaging modality that provides excellent optical contrast with the spatial resolution of ultrasound in vivo. The method is widely being investigated in the clinical setting for diagnostic applications in dermatology. In this report, we illustrate the utility of PAI as a non-invasive tool for imaging tattoos.

Photoacoustic and Magnetic Resonance Imaging of Hybrid Manganese Dioxide-Coated Ultra-small NaGdF Nanoparticles for Spatiotemporal Modulation of Hypoxia in Head and Neck Cancer.

There is widespread interest in developing agents to modify tumor hypoxia in head and neck squamous cell carcinomas (HNSCC). Here, we report on the synthesis, characterization, and potential utility of ultra-small NaYF:Nd/NaGdF nanocrystals coated with manganese dioxide (usNP-MnO) for spatiotemporal modulation of hypoxia in HNSCC. Using a dual modality imaging approach, we first visualized the release of Mn using T1-weighted magnetic resonance imaging (MRI) and modulation of oxygen saturation (%sO) using photoacoustic imaging (PAI) in vascular channel phantoms.

Development and Validation of a Clinically Relevant Workflow for MR-Guided Volumetric Arc Therapy in a Rabbit Model of Head and Neck Cancer.

There is increased interest in the use of magnetic resonance imaging (MRI) for guiding radiation therapy (RT) in the clinical setting. In this regard, preclinical studies can play an important role in understanding the added value of MRI in RT planning. In the present study, we developed and validated a clinically relevant integrated workflow for MRI-guided volumetric arc therapy (VMAT) in a VX2 rabbit neck tumor model of HNSCC.

H magnetic resonance spectroscopy of H-to-H exchange quantifies the dynamics of cellular metabolism in vivo.

Quantitative mapping of the in vivo dynamics of cellular metabolism via non-invasive imaging contributes to our understanding of the initiation and progression of diseases associated with dysregulated metabolic processes. Current methods for imaging cellular metabolism are limited by low sensitivities, costs or the use of specialized hardware. Here, we introduce a method that captures the turnover of cellular metabolites by quantifying signal reductions in proton magnetic resonance spectroscopy (MRS) resulting from the replacement of H with H.

Performance Characteristics of Photoacoustic Imaging Probes with Varying Frequencies and Light-delivery Schemes.

Photoacoustic imaging (PAI) is an emerging biomedical imaging technique that utilizes a combination of light and ultrasound to detect photoabsorbers embedded within tissues. While the clinical utility of PAI has been widely explored for several applications, limitations in light penetration and detector sensitivity have restricted these studies to mostly superficial sites. Given the importance of PA signal generation and detection on light delivery and ultrasound detector frequency, there is an ongoing effort to optimize these parameters to enhance photoabsorber detection at increased depths.

Dynamic photoacoustic imaging of neurovascular coupling in salivary glands.

The purpose of this study was to apply photoacoustic imaging (PAI), a relatively new imaging method, to non-invasively map neurovascular dynamics in salivary glands. Dynamic PAI with co-registered ultrasound (US) was performed in mice to monitor salivary gland hemodynamics in response to exogenous muscarinic receptor stimulation (pilocarpine) and blockade (atropine). Pilocarpine increased salivary gland oxygen saturation (%sO) within minutes after administration, which was abrogated by atropine.

An ABCG2 non-substrate anticancer agent FL118 targets drug-resistant cancer stem-like cells and overcomes treatment resistance of human pancreatic cancer.

Background: Pancreatic cancer is a deadly disease with a very low 5-year patient survival rate of 6-8%. The major challenges of eliminating pancreatic cancer are treatment resistance and stromal barriers to optimal drug access within the tumor. Therefore, effective molecular targeting drugs with high intra-tumor access and retention are urgently needed for managing this devastating disease in the clinic.

Photoacoustic Imaging as an Early Biomarker of Radio Therapeutic Efficacy in Head and Neck Cancer.

The negative impact of tumor hypoxia on radiotherapeutic efficacy is well recognized. However, an easy to use, reliable imaging method for assessment of tumor oxygenation in routine clinical practice remains elusive. Photoacoustic imaging (PAI) is a relatively new imaging technique that utilizes a combination of light and ultrasound (US) to enable functional imaging of tumor hemodynamic characteristics .

Visualizing the effects of metformin on tumor growth, vascularity, and metabolism in head and neck cancer.

Background: The antidiabetic drug metformin (Met) is believed to inhibit tumor proliferation by altering the metabolism of cancer cells. In this study, we examined the effects of Met on tumor oxygenation, metabolism, and growth in head and neck squamous cell carcinoma (HNSCC) using non-invasive multimodal imaging.

Materials And Methods: Severe combined immunodeficient (SCID) mice bearing orthotopic FaDu HNSCC xenografts were treated with Met (200 mg/kg, ip) once daily for 5 days.

Spatiotemporal Optoacoustic Mapping of Tumor Hemodynamics in a Clinically Relevant Orthotopic Rabbit Model of Head and Neck Cancer.

The purpose of this study was to investigate the usefulness of photoacoustic imaging (PAI) for spatiotemporal mapping of tumor hemodynamics in a rabbit model of head and neck carcinoma. Shope cottontail rabbit papilloma virus associated VX2 carcinomas were established in adult male New Zealand White rabbits (n = 9) by surgical transplantation of tumor tissue in the neck. Noninvasive PAI with co-registered ultrasound (US) was performed to longitudinally monitor tumor growth, oxygen saturation (%sO), and hemoglobin concentration (HbT).

Photoacoustic monitoring of tumor and normal tissue response to radiation.

Hypoxia is a recognized characteristic of tumors that influences efficacy of radiotherapy (RT). Photoacoustic imaging (PAI) is a relatively new imaging technique that exploits the optical characteristics of hemoglobin to provide information on tissue oxygenation. In the present study, PAI based measures of tumor oxygen saturation (%sO2) were compared to oxygen-enhanced magnetic resonance imaging (MRI) measurements of longitudinal relaxation rate (R1 = 1/T1) and ex-vivo histology in patient derived xenograft (PDX) models of head and neck cancer.

Photoacoustic imaging of salivary glands.

In this work, we utilized photoacoustic imaging (PAI) with co-registered ultrasound (US) to non-invasively assess salivary gland function in vivo. A significant increase in salivary gland oxygen saturation was observed on PAI within minutes after gustatory stimulation of healthy mice reflective of the hyperemic response associated with secretion of saliva. Good correlation was seen between PAI and Doppler sonography.

Photoacoustic imaging of vascular hemodynamics: validation with blood oxygenation level-dependent MR imaging.

Purpose: To noninvasively assess vascular hemodynamics with photoacoustic imaging (PAI) and blood oxygenation level-dependent (BOLD) magnetic resonance (MR) imaging in phantoms and in an animal model.

Materials And Methods: In vivo studies were performed with institutional animal care and use committee approval. In vitro experiments were performed by using a tissue-mimicking phantom in multiple oxygenation conditions (n = 6) to compare PAI measurements and BOLD MR imaging measurements.

Non-invasive multimodal functional imaging of the intestine with frozen micellar naphthalocyanines.

There is a need for safer and improved methods for non-invasive imaging of the gastrointestinal tract. Modalities based on X-ray radiation, magnetic resonance and ultrasound suffer from limitations with respect to safety, accessibility or lack of adequate contrast. Functional intestinal imaging of dynamic gut processes has not been practical using existing approaches.