Advances In Noninvasive Imaging Research Articles

Bicuspid aortic valve-associated aortopathy: update on biomarkers.

Bicuspid aortic valve (BAV)-associated aortopathy is common and its progression for individual patients is difficult to predict. The present review aims to identify recent developments using biomarkers for the determination of risk and progression of disease in patients with BAV aortopathy. Novel rare genetic variants and epigenetic methylation signatures affecting non-cytosine phosphate guanine (non-CpG) and CpG sites, nicotinamide phosphoribosyltransferase and Sod expression may lead to improved prediction of the aortopathy phenotype. Circulating transforming growth factor β-1/endoglin and miRNA signatures are found to be indicative of aortic dilation. Aortic miRNA, sphingomyelin and oxidative stress levels are linked to aortopathy progression and aortic dilation. Further evidence is shown that the pattern of cusp fusion in BAV may influence the location and extent of aortopathy. The clinical phenotypic variability seen in BAV patients suggests complex interactions between genetic variants, epigenetic regulation modifications and the variable effect of valve-mediated hemodynamic flow disturbances on the aorta and its secreted markers. Emerging biomarkers may serve along with advanced noninvasive imaging modalities to precisely identify risk of aortic complications and identify those patients who are in need of surgical intervention.

Advanced Non-invasive Imaging Techniques in Chronic Heart Failure and Cardiomyopathies : Focus on Cardiac Magnetic Resonance Imaging and Computed Tomographic.

Cardiomyopathies (Cs) are a heterogeneous group of myocardial diseases with structural and/or functional abnormalities.The aetiology is due to genetic-family substrate in most cases, however, the correct and detailed analysis of morphofunctional abnormalities (severity and distribution of hypertrophy, ventricular dilatation, ventricular dysfunction) and tissue characteristics (myocardial fibrosis, myocardial infiltration) are a crucial element for a definite diagnosis.Among the different diagnostic imaging modalities applied in clinical practice (echocardiography, nuclear medicine), cardiac magnetic resonance (CMR) has emerged as a non-invasive diagnostic tool having high ability to quantify systolic function and tissue abnormalities that represent the substrates of many Cs.The main added value of CMR is the ability to identify cardiomyopathies with respect to ischemic heart disease and, above all, to discriminate the major types of cardiomyopathies based on morpho-functional presentation patterns and the presence and location of myocardial fibrosis.Many CMR elements allow increasing diagnostic accuracy but CMR data should be integrated with an appropriate clinical and instrumental context.Computed Tomographic (CT) scan technology has showed a complementary role in patients having Cs and HF.In this chapter, the diagnostic, pathophysiologic and prognostic value of CMR and CT in heart failure due to the most common cardiomyopathies will be discussed.

Clinical significance of ST depression at exercise stress testing in competitive athletes: usefulness of coronary CT during screening.

Congenital coronary anomalies (CCAs) and coronary artery disease (CAD) arouse intense scientific and clinical interest in sports medicine and sports cardiology medical communities because of their potential to trigger sudden cardiac death (SCD) in athletes. Exercise stress testing represent the first instrumental assessment to evaluate electrocardiographic changes during effort. Coronary computed tomography angiography (CCTA) is an advanced accurate noninvasive imaging modality for excluding CAD and abnormalities of origin and course of coronary vessels. The aim of this study is to investigate with CCTA the clinical significance of ST depression suggestive for myocardial ischemia during exercise stress testing in athletes and to determine the prevalence of CAD and/or CCAs. Sixty-five consecutive athletes showing electrocardiographic findings positive or equivocal for myocardial ischemia on exercise stress testing during pre-participation screening were investigated with CCTA. Among the 65 athletes investigated, 36 showed Myocardial Bridge (MB), one showed an anomalous coronary origin and seven showed CAD. Among 36 athletes with MB, 4 were associated with mild coronary artery stenosis. Three athletes with CAD needed percutaneous transluminal coronary angioplasty or coronary artery bypass surgery. In competitive athletes even with excellent workload capacities, in absence of cardiomyopathy, the presence of ischemic electrocardiographic abnormalities could be mainly determined by a coronary congenital or acquired pathology. In this population CCTA is a useful imaging modality of choice for the risk stratification and for the diagnostic process, to allow eligible athletes to compete and to follow-up subjects requiring medical surveillance.

Fractional flow reserve computed tomography in the evaluation of coronary artery disease.

Amongst patients with suspected obstructive coronary artery disease (CAD), less than a third of patients have obstructive disease on invasive coronary angiography (ICA) and fewer still have flow-limiting obstructive disease as determined by invasive fractional flow reserve (FFR). FFR is a powerful tool in guiding revascularization of flow-limiting lesions which in turn improves clinical outcome in those with haemodynamically significant obstructive disease. However FFR is infrequently performed due to the cost, time and patient discomfort the procedure entails. Further advances in non-invasive imaging has allowed FFR to be derived non-invasively by applying computational fluid dynamic (CFD) modeling to the coronary computed tomography angiography (CCTA) dataset without the need to induce hyperemia or modify the standard CCTA acquisition protocol. FFR derived from CCTA has been shown to have excellent correlation with invasive FFR and remains diagnostically robust in presence of reduced signal-to-noise ratio (SNR), coronary calcification and motion artifact. More recently, new data have emerged evaluating the clinical impact of fractional flow reserve computed tomography (FFRCT) on the assessment and management of patients with stable chest pain. One such study is the Prospective LongitudinAl trial of FFRCT: Outcome and Resource IMpacts (PLATFORM) study which showed an improved patient selection for ICA using CCTA-FFRCT approach by increasing the likelihood of identifying obstructive CAD at ICA amongst those intended for invasive testing. CCTA-FFRCT may therefore serve as efficacious gatekeeper to ICA that enriches the ICA population. The utility of FFRCT has also helped deepened our understanding of CAD. Through CFD modeling, it is now recognized that there are mechanistic forces of wall shear stress (WSS) and axial plaque force acting on coronary plaques. This has created further interest in exploring the possible interplay between these mechanistic forces on the development of coronary plaque and vulnerability of these plaques to rupture.

The Right Heart: Acute and Chronic Issues.

Cardiovascular remodeling in response to sustained moderate and high-intensity exercise is a well-established phenomenon. Following more than a century of work focused on the left ventricle (LV), remodeling of the right side of the heart has recently become a topic of considerable scientific and clinical interest. Morphologic and functional changes have now been well documented in the right ventricle (RV) after isolated bouts of endurance exercise and in association with long-term sustained training. Although exercise-induced cardiac remodeling is classically viewed as an adaptive, clinically benign process, it has recently been hypothesized that repetitive bouts of intense exercise may trigger pathologic changes in the RV characterized by patchy fibrosis and a predisposition to arrhythmia. At present, this concept remains speculative due to the absence of definitive clinical data. While we await scientific clarification of this intriguing hypothesis, several practical clinical considerations are noteworthy. RV dilation is common among trained endurance athletes. As such, asymptomatic athletes with RV dilation do not require additional diagnostic evaluation unless dilation is accompanied by substantial decrements in systolic function or other structural abnormalities suggestive of genetic heart disease. In contrast, RV dilation among athletes with either symptoms or a family history of genetic heart disease requires extensive multi-modality assessment including maximal effort-limited exercise testing, ambulatory rhythm monitoring, advanced non-invasive imaging, and invasive electrophysiology study. This review will discuss the contemporary understanding of how the RV responds to exercise with an emphasis on the relevance of this phenomenon in clinical cardiovascular practice.

Transthoracic 3D Echocardiographic Imaging of Type A Aortic Dissection – Case Presentation

Abstract In type A aortic dissection (AoD) an early and accurate diagnosis is essential to improve survival, by applying urgent surgical repair. 3D transthoracic echocardiography (3D-TTE), an advanced noninvasive imaging technique, could offer a comprehensive evaluation of the ascending aorta and aortic arch in this regard. Both modalities of real-time 3D imaging – live 3D and full-volume aquisition – proved to be useful in evaluating the localization and extent of AoD. Our case illustrates the utility of 3D-TTE in the complex assessment AoD. By providing the proper anatomical dataset, 3D-TTE could facilitate considerably the diagnosis of type A AoD.

Standardized Approach to Quantitatively Measure Residual Limb Skin Health in Individuals with Lower Limb Amputation.

Objective: (1) Develop a standardized approach to quantitatively measure residual limb skin health. (2) Report reference residual limb skin health values in people with transtibial and transfemoral amputation. Approach: Residual limb health outcomes in individuals with transtibial (n = 5) and transfemoral (n = 5) amputation were compared to able-limb controls (n = 4) using noninvasive imaging (hyperspectral imaging and laser speckle flowmetry) and probe-based approaches (laser doppler flowmetry, transcutaneous oxygen, transepidermal water loss, surface electrical capacitance). Results: A standardized methodology that employs noninvasive imaging and probe-based approaches to measure residual limb skin health are described. Compared to able-limb controls, individuals with transtibial and transfemoral amputation have significantly lower transcutaneous oxygen tension, higher transepidermal water loss, and higher surface electrical capacitance in the residual limb. Innovation: Residual limb health as a critical component of prosthesis rehabilitation for individuals with lower limb amputation is understudied in part due to a lack of clinical measures. Here, we present a standardized approach to measure residual limb health in people with transtibial and transfemoral amputation. Conclusion: Technology advances in noninvasive imaging and probe-based measures are leveraged to develop a standardized approach to quantitatively measure residual limb health in individuals with lower limb loss. Compared to able-limb controls, resting residual limb physiology in people that have had transfemoral or transtibial amputation is characterized by lower transcutaneous oxygen tension and poorer skin barrier function.

The future of imaging in cardiovascular disease intervention trials: 2017 and beyond.

As our understanding of cardiovascular disease has advanced over the past decades, multiple novel treatment strategies have been developed with the hope of reducing the global morbidity and mortality associated with this condition. Large-scale trials to test such novel therapies using clinical end points are expensive, leading to interest in phase II clinical trials with imaging-derived outcome measures. Noninvasive imaging techniques that assess changes in both atherosclerotic disease burden and plaque composition in response to therapy are well established. With the advent of molecular techniques and hybrid imaging, we now have the ability to assess disease activity alongside these standard anatomic assessments. This multifaceted approach has the potential to provide a more comprehensive assessment of the actions and efficacy of novel therapies in the carotids, aorta and coronary arteries. This review will examine how advanced noninvasive imaging strategies have been used to investigate drug efficacy in intervention trials to date, and crucially how these approaches are set to evolve and play a central role in developing the next generation of atherosclerotic medication.

Carotid and Vertebral Dissection Imaging.

Carotid or vertebral artery dissection is the result of a tear in the vessel lining wherein the intima separates the media. This creates a false or pseudo lumen, often accompanied by hemorrhage into the arterial wall. Dissection of these craniocervical vessels often manifests with pain alone but, if untreated, may result in severe neurologic compromise. The causes of dissection are multifactorial, including spontaneous, iatrogenic, and traumatic insults. Regardless of etiology, treatment consists primarily of anticoagulation, whereas endovascular therapy is reserved for cases with persistent thrombus or flow limitation. Given the high risk of neurological compromise or death and the propensity of these injuries to occur in younger individuals, early diagnosis of carotid and vertebral artery dissections is critical. Although angiography remains the criterion standard for diagnosis, advances in noninvasive imaging have placed magnetic resonance and computed tomography at the forefront of diagnosis. This article examines the current imaging modalities used to diagnose this under-recognized entity.

Current views on anthracycline cardiotoxicity.

Anthracyclines are well established and effective anticancer agents used to treat a variety of adult and pediatric cancers. Unfortunately, these drugs are also among the commonest chemotherapeutic agents that have been recognized to cause cardiotoxicity. In the last years, several experimental and clinical investigations provided new information and perspectives on anthracycline-related cardiotoxicity. In particular, molecular mechanisms of cardiotoxicity have been better elucidated, early diagnosis has improved through the use of advanced noninvasive cardiac imaging techniques, and emerging data indicate a genetic predisposition to develop anthracycline-related cardiotoxicity. In this article, we review established and new knowledge about anthracycline cardiotoxicity, with special focus on recent advances in cardiotoxicity diagnosis and genetic profiling.

Use of Noninvasive Imaging in Cardiac Amyloidosis.

Cardiac involvement in amyloidosis is associated with poor outcomes. The standard test for the diagnosis of cardiac amyloidosis is endomyocardial biopsy but given current advances in noninvasive imaging, the diagnosis is frequently obtained or strongly suspected without biopsy. Echocardiography is the most utilized cardiac imaging modality, particularlymyocardial strain measures with this modality have been found to be a predictor of clinical outcomes, superior to traditional parameters. Other known imaging modalities with new, useful protocols for this pathology include nuclear imaging and cardiac magnetic resonance (CMR). In particular, CMR has excellent sensitivity and specificity.

Advances in noninvasive imaging of melanoma.

Melanoma is the most dangerous type of skin cancer and its incidence has risen sharply in recent decades. Early detection of disease is critical for improving patient outcomes. Any pigmented lesion that is clinically concerning must be removed by biopsy for morphologic investigation on histology. However, biopsies are invasive and can cause significant morbidity, and their accuracy in detecting melanoma may be limited by sampling error. The advent of noninvasive imaging devices has allowed for assessment of intact skin, thereby minimizing the need for biopsy; and these technologies are increasingly being used in the diagnosis and management of melanoma. Reflectance confocal microscopy, optical coherence tomography, ultrasonography, and multispectral imaging are noninvasive imaging techniques that have emerged as diagnostic aids to physical exam and/or conventional dermoscopy. This review summarizes the current knowledge about these techniques and discusses their practical applications and limitations.

Abstract 200: Collaterals in SWIFT PRIME: Imaging Correlates and Ultimate Impact

Background: The overwhelming benefit of endovascular stroke therapy established in recent trials fueled by rapid workflow, modern devices and favorable noninvasive imaging profiles newly question the impact of collateral grade. We analyzed the SWIFT PRIME trial to evaluate the role of collaterals with respect to advanced imaging selection, the pace of infarct growth and ultimate clinical outcomes. Methods: Conventional angiography of the endovascular arm in SWIFT PRIME (n=98) was reviewed by 3 independent readers that scored ASITN/SIR collateral flow grade, followed by consensus adjudications. Angiographic collaterals were scored only when available, prior to use of the Solitaire stent retriever. Statistical analyses investigated the relationship of collateral grade with clinical and imaging variables in the main trial dataset. Results: 70 endovascular arm subjects (mean age 65.2±12.1 years, 35 (50%) women) had angiographic collaterals scored by 3 independent readers ( W =0.93). Pretreatment CT or MR perfusion imaging was obtained in 92% of cases, associated with a relatively wide range of angiographic collateral grades (1, n=6 (9%); 2, n=25 (36%); 3, n=37 (53%); 4, n=2 (3%)) with a preponderance (79%) of M1 occlusions. Worse collaterals were associated with prior myocardial infarction (33% (grade 1), 8% (grade 2), 3% (grades 3, 4); p=0.03) but unrelated to age, sex, or other co-morbidities or time from stroke onset. Baseline ASPECTS (median 9, r=0.20) trended higher (p=0.09) in those with more robust collaterals. Collaterals were unrelated to degree of TICI reperfusion, yet the presence of distal emboli at procedure end was linked with worse collaterals (p=0.008). More robust collaterals exhibited a potent and graded link with better day 90 mRS (r=- 0.3, p=0.03) and lower mean NIHSS at 27 hours (r=-0.3, p=0.03), whereas infarct growth at 27 hours was unrelated (r=-0.07, p=0.60). Conclusions: Use of advanced noninvasive perfusion imaging enrolls patients with more robust collateral grades, yet a diverse range of collaterals may be seen. Even with rapid workflow, mismatch based selection and successful reperfusion, the degree of angiographic collaterals continues to be strongly associated with clinical outcomes at all timepoints.

Thermal impact of near-infrared laser in advanced noninvasive optical brain imaging.

The propagation of laser light in human tissues is an important issue in functional optical imaging. We modeled the thermal effect of different laser powers with various spot sizes and different head tissue characteristics on neonatal and adult quasirealistic head models. The photothermal effect of near-infrared laser (800nm) was investigated by numerical simulation using finite-element analysis. Our results demonstrate that the maximum temperature increase on the brain for laser irradiance between 0.127 (1mW) and [Formula: see text] (100mW) at a 1mm spot size, ranged from 0.0025°C to 0.26°C and from 0.03°C to 2.85°C at depths of 15.9 and 4.9mm in the adult and neonatal brain, respectively. Due to the shorter distance of the head layers from the neonatal head surface, the maximum temperature increase was higher in the neonatal brain than in the adult brain. Our results also show that, at constant power, spot size changes had a lesser heating effect on deeper tissues. While the constraints for safe laser irradiation to the brain are dictated by skin safety, these results can be useful to optimize laser parameters for a variety of laser applications in the brain. Moreover, combining simulation and adequate in vitro experiments could help to develop more effective optical imaging to avoid possible tissue damage.

Small is Smarter: Nano MRI Contrast Agents - Advantages and Recent Achievements.

Many challenges for advanced sensitive and noninvasive clinical diagnostic imaging remain unmatched. In particular, the great potential of magnetic nano-probes is intensively discussed to further improve the performance of magnetic resonance imaging (MRI), especially for cancer diagnosis. Based on recent achievements, here the concepts of magnetic nanoparticle-based MRI contrast agents and tumor-specific imaging probes are critically summarized. Advances in their synthesis, biocompatible chemical and biofunctional surface modifications, and current strategies for further developing them into multimodality imaging probes are discussed. In addition, how engineered versus unintended surface coatings such as protein coronas affect the biocompatibility and performance of MRI nano-probes is also considered. To stimulate progress in the field, future strategies and relevant challenges that still need to be resolved in the field conclude this review.

Echocardiography in pulmonary hypertension.

Pulmonary hypertension is a progressive disease of the pulmonary vasculature characterized by increased vascular resistance and pressure overload of the right ventricle. This review aims to describe the diagnostic and prognostic role of echocardiography in pulmonary hypertension with particular consideration of relative strengths, weaknesses and new advances. Although right heart catheterization (RHC) remains the gold standard, echocardiography represents an accessible and feasible real-world tool for screening, differential diagnostic, follow-up assessments and risk stratification in pulmonary hypertension. In the context of clinical scenario and multimaging approach, echocardiography provides accurate measurements of pulmonary haemodynamics, either at rest and/or during exercise, and is particularly useful in ruling out secondary causes of pulmonary hypertension and/or detecting preclinical stages. The use of advanced noninvasive imaging techniques may provide additional information in assessing right heart structure and function. Advances in echocardiography and the multimodality imaging approach continue to provide new understandings and opportunities for the study of the right heart-pulmonary circulation unit in pulmonary hypertension.

Imaging of congenital heart disease in adults.

Imaging is fundamental to the lifelong care of adult congenital heart disease (ACHD) patients. Echocardiography remains the first line imaging for inpatient, outpatient, or perioperative care. Cross-sectional imaging with cardiovascular magnetic resonance (CMR) or computed tomography (CT) provides complementary and invaluable information on cardiac and vascular anatomy and other intra-thoracic structures. Furthermore, CMR provides quantification of cardiac function and vascular flow. Cardiac catheterization is mostly reserved for assessment of pulmonary vascular resistance, ventricular end-diastolic pressure, and percutaneous interventions. There have been further advances in non-invasive imaging for ACHD including the application of advanced echocardiographic techniques, faster automated CMR imaging, and radiation dose reduction in CT. As a result ACHD, a heterogeneous population, benefit from appropriate application of multiple imaging modalities matched with tertiary ACHD expertise.

Noninvasive vascular imaging of moyamoya: Diagnosis, followup, and surgical planning

Moyamoya disease and syndrome are typically described by their imaging features on cerebral angiography, however advances in noninvasive imaging has allowed improved anatomic and physiologic characterization of this vascular abnormality. Advanced imaging complements the role of cerebral angiography, and when used appropriately can provide valuable information regarding the diagnosis, treatment planning, and surveillance in patients with moyamoya. Techniques to be aware of include computed tomography, CT-angiography, Magnetic Resonance Imaging, MR Angiography (time-of-flight and dynamic contrast enhancemed angiography), and perfusion imaging (CT perfusion, arterial spin labeling perfusion, and nuclear medicine perfusion). With an appropriate understanding and implementation of noninvasive techniques, this disease process can be better understood allowing for improved patient management.

FIRST IN MAN OBSERVATIONS WITH SIMULTANEOUS 18F-FDG PET AND MR IMAGING IN PERIPHERAL ARTERY DISEASE USING A WHOLE-BODY INTEGRATED SCANNER

Advanced non-invasive vascular imaging simultaneously combining positron emission tomography (PET) with magnetic resonance imaging (MRI) has recently been made possible. This observational study attempted to identify patients with peripheral artery disease (PAD) at risk for vascular events using

心臓カテーテル検査によって得られた結果をどう解釈するか

心エコー，CT，MRIなどの非侵襲的検査法の進歩に従い，心臓カテーテル造影検査はカテーテル治療の目的で施行されることが多くなり，多くの先天性心疾患（以下CHD）の術前のルーチンの検査として施行していた時代と比較してその適応は大きく変わった．現在の診断カテーテルの適応は，1）大動脈弁，僧房弁狭窄の重症度やFontan型手術適応など，より正確な血行動態評価が必要な時，2）心奇形の形態異常が非侵襲的検査法では充分に描出されず評価できない時，3）カテーテル治療を計画し，その前に施行する場合，4）肺動脈閉塞性病変の有無を決定するなど，血行動態評価が治療方針の決めてとなる時，5）電気生理学的検査，または生検が必要な時，などである．このように以前と診断カテーテルの適応は変わったが，未だCHDの，特に複雑心奇形の形態，血行動態を評価する“Gold Standard”な検査として施行されている．このReviewでは酸素飽和度，圧などから計算される血行動態の指標や造影所見などをいかに得て，どう解釈するかについて概説した．