New Heart Imaging Techniques to Evaluate Possible Heart Disease

Specialized imaging techniques now available allow a unique opportunity to characterize the micro-environment of the human body. Magnetic Resonance (MR) vascular wall imaging and angiography (MRA) are developing techniques that permit non-invasive evaluation of arterial and venous structures without the need for x-ray based catheter angiography. In addition, vessel wall imaging provides unprecedented non-invasive tools to assess vascular endothelial function. While dramatic progress has been made to cardiovascular MR imaging in the last few years, there are still substantial limitations in the resolution, accuracy, and reproducibility of MRA and wall imaging in the comprehensive structural and functional evaluation of coronary artery. The first aim of this study is to develop and optimize clinical imaging protocols and techniques for fast high-resolution coronary MRA and wall imaging for the assessment of coronary and other main arteries structural, distensibility, and endothelial functional parameters. Technique optimization and performance evaluation will be accomplished in normal subjects without known or suspected coronary atherosclerosis. The second aim of this protocol is to evaluate early MR imagery signs of arterial structural, distensibility, and endothelial functional disorders associated with atherosclerosis in a cohort of patients with known or suspected coronary atherosclerosis. Results from accelerated high-resolution MRA will be correlated with corresponding Computerized Tomography Coronary Angiogram (CTA) results. The third aim of this protocol is to develop, implement, and optimize new non-invasive methods for characterization of the micro-environment in the thoracic and abdominal area utilizing specialized techniques such as MR Spectroscopy, MR Elastography, and blood oxygenation level dependent (BOLD) imaging. The long-term objective of this study and research initiative is to optimize coronary MRA, wall, and body imaging techniques to the point that it can reliably be used for routine prevention and assessment of early atherosclerosis and other diseases.

Quantitative Cardiac Parametric Mapping

Placental Imaging Techniques

Background: This study is a proof-of-concept, case-control exploration of quantitative ultrasound (QUS) and ultrafast power Doppler imaging (uPDI) imaging techniques, applied to the placenta to evaluate health of the placenta, blood flow visualized by colored doppler imaging in patients with and without FGR. Investigators will utilize the Verasonics Vantage 256 research ultrasound machine (Verasonics, Inc, Kirkland, WA) for this study, which is not FDA approved/experimental, along with a standard-of-care Phillips ultrasound machine which is FDA approved. Use of QUS gained interest within the 1980s to evaluate the health of a range of tissues, from myocardial [heart muscle], to artery plaques, to breast masses, to bone density. More recently, there has been great interest in QUS for evaluation of fetal tissue health, including fetal liver and lung tissue, as well as placental tissue to gauge both gestational age as well as placental health. QUS imaging creates a number of values including an attenuation coefficient estimate (ACE), specified in decibels (dB) which is a measurement of the ultrasound waves' absorption and scattering as they move through human tissue. QUS also generates other values including a frequency-dependent attenuation value. These numerical estimates of absorption and scattering along with others provided by QUS are believed to change within the placenta with increased gestational age due to increasing deposition of collagen and fibrin, two types of connective fibers. Measures of absorption, scattering, and related tissue properties may also be altered in unhealthy versus healthy placental tissue. Thus, QUS is believed to have the potential to inform the clinician about placental health which may be affected by uteroplacental insufficiency predisposing to fetal growth restriction. Researchers will also investigate power Doppler imaging (uPDI), a newer ultrasound modality that uses an ultra-high frame rate and clutter filtering to increase the Doppler imaging sensitivity. Traditional Doppler ultrasound displays color onto the normally greyscale ultrasound where blood flow is seen by the machine. However, traditional ultrasound with Doppler has difficulty in detecting blood flow within smaller vessels, such as the smallest spiral arteries of the placenta which provide nutrient and gas exchange to the fetus. It is believed uPDI may be able to better visualize these small vessels and other small areas of slow blood flow or pooled blood within the placenta, providing more direct evaluation of placental tissue perfusion and health. Procedure: Ultrasounds will be performed every 3 weeks until delivery for both cohorts following informed consent. The first ultrasound will take place within 1 week of enrollment to allow for the sonographer to be scheduled. Ultrasounds will be performed by trained MFM sonographers. Ultrasounds will take place within the Maternal Fetal Medicine suite of Carilion Clinic [102 Highland Ave, Roanoke, VA], in clinical exam rooms with dimmable lights and calming music to reduce patient stress. Upon entering the exam room, IRB-approved study team members and/or sonographers will introduce themselves by name and capacity, then ask the name and date of birth of the subject to verify subject identity against the research enrollment log and EMR. The purpose for the visit will be reiterated and the subject's wish to continue to participate in the research will be verified to ensure continued consent. Any questions the subject has will be answered to the subject's satisfaction. An agenda for the encounter will be set by the IRB-approved study team member or sonographer, so the patient knows what to generally expect and how long the visit will take. The subject will be seated in a reclined position and asked to raise the bottom portion of their shirt, while the sonographer drapes the patient according to standard clinical procedure. Ultrasound gel will be applied to the subject's abdomen and the sonographer will then begin the ultrasound using the machine's transducer [part held in sonographer's hand]. To begin, an ultrasound using a standard-of-care, Philips ultrasound machine will be used to first verify continued fetal viability and perform a basic anatomical survey to ensure continued eligibility for the subject's given cohort [either Case [FGR-positive] or Control [FGR-negative]]. These Philips ultrasound machines are located in each of the standard MFM exam rooms. Following this, the sonographer will transition to the research ultrasound machine for the rest of the visit. Participants will have research ultrasounds performed of their placentas using a Verasonics Vantage 256 system (a popular research ultrasound platform used for human imaging under IRB approval). The gestational age of the fetus, estimated fetal weight in grams, and growth/weight percentile measurements for that gestational age will be recorded during the research visits. The placenta will be scanned at a central, peripheral, and 'mid-disc' region to acquire QUS and uPDI images with the Verasonics research ultrasound as well. Three measurements will be acquired at these locations. The Verasonics machine will be programmed to project B-mode (brightness mode) images for the sonographer at the time of the research ultrasound for confirmation of correct placental location. These B- or brightness mode images will project a 2-dimensional, greyscale image of the placenta (or fetus) to the sonographer to orient him/her to the location they are scanning and find the placenta. The machine will be programmed to display thermal index (TI) and mechanical index (MI) during all exams, which are derived estimates of the heat and pressure created by ultrasound waves' energy. These are displayed for safety and kept within International Society of Ultrasound of Obstetrics and Gynecology (ISUOG) guidelines. The Verasonics machine will be programmed with a "hard stop" not to exceed these limits. The energy exposure from Ultrasound has no known cumulative effect. Following the ultrasound procedure, the subject will be cleaned of ultrasound gel with a cloth and drapes removed. The subjects will be told of any changes noticed since the last visit to the growth or health of their baby or placenta. Incidental findings obtained during the research ultrasound will be shared with the subject's routine clinical provider and the patient by IRB-approved and qualified physicians on the research team. The PI will advise the participant's routine clinical provider that all results obtained with the research ultrasound should be validated using an FDA Approved ultrasound and standard of care ultrasound techniques. Following all research ultrasound procedures during the visit, subjects will be given an opportunity to ask any further questions they wish and receive answers to their satisfaction. Printouts of their baby from the standard-of-care ultrasound machine will be provided to subjects. Subjects will then be led back out of the MFM suite to the front desk where they will be scheduled for their next research visit. Participants will not be under the primary care of the research physicians. The research physicians will not be involved in decisions regarding the timing, method, or procedures used to terminate a pregnancy or determining the viability of a neonate. Analysis: Researchers will evaluate QUS and uPDI images of the placentas. Researchers will evaluate which QUS parameters are most strongly associated with FGR diagnosis by comparing them to numbers obtained by QUS in normal estimated fetal growth pregnancies. Researchers will examine uPDI images in FGR pregnancies versus those obtained from normal growth weight pregnancies. Secondary analysis: Researchers will perform multimodal analysis to determine whether these ultrasound modalities can distinguish between pregnancies with: A.) confirmed diseases deriving from a placental origin; B.) abnormal umbilical artery assessments, severe FGR, preeclampsia and stillbirth; C.) no complications.

Imaging Techniques in MRI

Magnetic Resonance (MR) Imaging performed on volunteers will be used to develop and optimize techniques useful in the advancement of MRI technology. The results will be used to evaluate the performance of new imaging methods and equipment on human subjects, and to provide essential ground work for research and development for use in future patients. MR imaging is a non invasive technology, though some scans, dependent on imaging area and researcher preference, may be performed with MR contrast -- gadolinium (Gd) --given intravenously.

Optimization of Patient Preparation and Imaging Techniques for Cardiac CT

CT scans are widely utilized due to technological advancements that enable rapid imaging of large anatomical areas, aiding in the assessment of critically ill patients. CT imaging works by detecting how different tissues absorb X-ray radiation, with denser tissues absorbing more. Contrast agents enhance tissue differentiation, but their administration must be carefully managed to minimize potential side effects, such as arrhythmias or kidney impairment. For CCTA, maintaining a low and stable heart rate is essential to reduce motion artifacts. Beta-blockers are commonly used for this purpose. This study evaluates different patient preparation strategies by comparing the effects of oral and intravenous beta-blockers on heart rate. A total of 240 participants will be enrolled and randomized into four groups, with one group also receiving an auditory intervention involving music. Heart rate measurements will be obtained using a cardiac output meter, while participants will evaluate their sensory experiences and warmth perception using visual analog scales. The study also aims to determine the optimal timing (s) for imaging following contrast administration, using cardiac output (L/min) and other participant variabels. A total of 240 participants (120 men and 120 women) will be enrolled and randomized into four groups of 60 individuals per group.

Extensive Resection of Malignant Brain Tumors Using Advanced Imaging Techniques

Novel Imaging Techniques for the Characterization of Musculoskeletal Tumors II

Comparison of values relating to the texture parameters of tumors evaluated by MRI and ultra-high resolution CT between benign and malignant lesions using histological analysis as the standard of reference. Comparison of the diagnostic performance of texture parameters derived from different MRI sequences and ultra-high resolution CT for musculoskeletal tumor characterization. Evaluate the impact of ultra-high resolution with respect to standard resolution on CT images Comparison of the diagnostic performance of the texture parameters for the tumor on the diagnostic performance of texture analysis derived parameters for the characterization of musculoskeletal tumors. Evaluate the effectiveness and accuracy of automatic artificial intelligence (AI) based tumor segmentation tools. Evaluate the use of trabecular analysis on ultra-high resolution CT images for the evaluation of tumor-bone interfaces.

Imaging Techniques for Identifying Factors of Sudden Cardiac Death Risk

Some people with heart disease and a weak heart muscle experience abnormal electrical activity of the heart that may predispose them to sudden death. In light of this risk, it has been recommended that such patients undergo implantation of an implantable cardioverter defibrillator (ICD). Your doctors have determined that you are such a patient and are to undergo implantation of an ICD. It is unclear who among the many patients who undergo ICD implantation for this reason are at greatest risk of sudden death and therefore require electrical response from their ICD. This research is being done to determine whether new imaging tests, such as magnetic resonance imaging (MRI) or multi-detector computed tomography (MDCT), can be used to predict who is at highest risk of sudden death and require electrical response from their ICD.

Study on Multimodal Imaging and Molecular Imaging Techniques in Degenerative Dementia

This project will build a longitudinal database based on multimodal MRI imaging information of dementia subjects, various body fluid or digital markers, and a cohort. The convolutional neural network algorithm will be used to explore the imaging characteristics of healthy controls, AD, FTD, and DLB, develop an early prediction model for degenerative dementia, and achieve early differential diagnosis of different dementia subtypes. This study further performed GE180, ASEM, and exendin-4 radionuclide imaging on some subjects who completed conventional PET (AV45, Tauvir, and FDG) imaging to explore the diagnostic efficacy of these three probes as new diagnostic probes for early AD. In addition, through longitudinal follow-up of Aβ-positive MCI patients, multimodal MRI and PET image fusion technology were used to explore the changes in fused images during their conversion to AD in order to obtain early and accurate diagnostic markers.

PRogression of Atheroma Evaluated by CT Angiography and IntraCoronary Imaging tEchniques

This is a combined cohort study with retrospectively and prospectively enrolled patients. Subjects with CAD detected by coronary CTA are consecutively enrolled. All the patients will undergo clinical follow-up for up to 5 years. Repeat coronary CTA will be conducted after 2 years. For patients referred to invasive coronary angiography, intracoronary imaging techniques, such as intravascular ultrasound (IVUS), optical coherence tomography (OCT), and near infrared spectroscopy (NIRS) will be performed. For all the prospectively enrolled patients, plasma and serum blood samples will be collected. The purpose of this study is to investigate the natural history of coronary atherosclerotic plaques in this population. Comprehensive morphological plaque analysis will be performed to evaluate total atheroma volume (TAV), percent atheroma volume (PAV), plaque composition, high risk plaque features, and characteristics of perivascular adipose tissue (PVAT). Functional analysis will also be conducted to calculate hemodynamic parameters such as wall shear stress (WSS), oscillatory shear index (OSI), relative residence time (RTT), transverse WSS (transWSS), axis plaque stress (APS), fractional flow reserve (FFR), and δFFR across lesions. The associations of these morphological and functional parameters with plaque progression and the onset of major adverse cardiovascular events (MACEs) will be analyzed. In addition, the impact of pharmacological treatments and the levels of cardiometabolic factors on coronary plaque progression will also be investigated. In the subpopulation who also receive intracoronary imaging examinations, intracoronary imaging modalities will be used to refine the inner and outer vessel contours, improve the accuracy of plaque composition characterization, and aid in the discovery of novel high-risk plaque features by coronary CTA.