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Organic molecular solids can exhibit rich phase diagrams. In addition to structurally unique phases, translational and rotational degrees of freedom can melt at different state points, giving rise to partially disordered solid phases. The structural and dynamic disorder in these materials can have a significant impact on the physical properties of the organic solid, necessitating a thorough understanding of disorder at the atomic scale. When these disordered phases form at low temperatures, especially in crystals with light nuclei, the prediction of material properties can be complicated by the importance of nuclear quantum effects. As an example, we investigate nuclear quantum effects on the structure and dynamics of the orientationally disordered, translationally ordered plastic phase of the acetylene:ammonia (1:1) co-crystal that is expected to exist on the surface of Saturn's moon Titan. Titan's low surface temperature (∼90 K) suggests that the quantum mechanical behavior of nuclei may be important in this and other molecular solids in these environments. By using neural network potentials combined with ring polymer molecular dynamics simulations, we show that nuclear quantum effects increase orientational disorder and rotational dynamics within the acetylene:ammonia (1:1) co-crystal by weakening hydrogen bonds. Our results suggest that nuclear quantum effects are important to accurately model molecular solids and their physical properties in low-temperature environments., (© 2024 Author(s). Published under an exclusive license by AIP Publishing.)

Objectives: TEE is performed in many patients with ischemic stroke, and it is possible to examine the proximal coronaries by TEE in these patients. Our purpose was to (1) determine the accuracy of transesophageal echocardiography (TEE) in the diagnosis of proximal coronary stenosis in patients with ischemic stroke and (2) show that TEE detection of proximal coronary stenosis changed management in a substantial number of patients., Methods: Thirty-two patients with ischemic stroke undergoing TEE, in whom the proximal coronaries were examined and who had angiographic results available, were studied., Results: Proximal coronaries were visualized as follows: left main (LM) in 31 (97%), left anterior descending (LAD) in 32 (100%), left circumflex (LCx) in 30 (94%) and right coronary artery (RCA) in 21 (66%). The sensitivity and specificity of TEE in diagnosing significant coronary stenosis in visualized vessels were as follows: LM 100% and 100%, LAD 100% and 95%, LCx 100% and 96%, and RCA 100% and 100%, respectively. When visualized and nonvisualized segments were considered, TEE detected significant stenosis as follows: 4 of 5 in the LM (80%), 13 of 13 in the LAD (100%), 2 of 3 in the LCx (66%), and 2 of 8 in the RCA (25%). Of the 32 patients, TEE results changed management in 17 patients (53%). Angiographic findings resulted in 10 of the 17 patients (59%) undergoing revascularization., Conclusions: TEE was very accurate in diagnosing significant coexisting coronary artery disease in patients with ischemic stroke. TEE diagnosis of these lesions prompted coronary angiography and subsequent revascularization in a substantial number of patients.

Coronary artery imaging is routinely obtained invasively at cardiac catheterization through coronary angiography. This remains the gold standard, but with advances in ultrasound technology, electron beam computed tomography, and magnetic resonance imaging, newer noninvasive methodologies are achieving greater success at imaging the coronary anatomy. This review is meant to highlight the important accomplishments from transesophageal echocardiographic (TEE) investigations that have studied the coronary arteries. The specific technique for optimally imaging the coronaries with high frequency transducers, color and conventional Doppler, in addition to contrast-enhanced methods, will be analyzed. Importantly, this article serves as a reminder to echocardiographers and cardiologists that excellent, clinically relevant information of the coronary arteries can be obtained routinely during TEE. This technique is part of the trend noted by the other authors in this special edition; that is, echocardiography is becoming the gold standard of the new millennium for many diagnostic areas, even coronary angiography.

We report a patient in whom we were able to make an accurate diagnosis of left carotid bulb and left internal carotid artery stenosis by carefully and slowly withdrawing the probe from the esophagus into the pharynx.

This study represents another example of the usefulness of transesophageal echocardiography in the assessment of stenosis involving the proximal, mid, and distal coronary arteries in stroke patients referred for exclusion of a cardiac source of embolism.

The present case reports demonstrate the incremental value of three-dimensional echocardiography over multiplane transesophageal two-dimensional imaging in the assessment of Lambl's excrescences (strands) involving the aortic valve.

We review the literature on Lambl's excrescences (valvular strands). With the widespread use of cardiac imaging modalities, most importantly, with transesophageal echocardiography, abnormal valvular structures are frequently identified on both native and prosthetic heart valves. However, there is no consensus in the literature on the correct terminology of these structures. The relationship between valvular strands (the so-called Lambl's excrescences) and papillary fibroelastomas has not been well established. In this review, we attempt to summarize the available echocardiographic descriptors and the gross macroscopic and histological features of Lambl's excrescences (valvular strands). In addition, we review the etiology, pathogenesis, and clinical implications of these cardiac excrescences. Also, we describe features that help to distinguish between Lambl's excrescences and papillary fibroelastomas. Because valvular strands (Lambl's excrescences) have been implicated in systemic thromboembolism, we also review the available management principles for patients with valvular strands; unfortunately, no specific therapeutic guidelines can be proposed at the present time.

This preliminary study demonstrates the feasibility of examining the proximal segments of the branches of the left subclavian artery during probe withdrawal toward the end of a routine transesophageal echocardiographic study. The branches identified most commonly were the vertebral and the internal mammary arteries.

Atherosclerosis is the leading cause of death worldwide. It encompasses several clinical entities, including coronary artery disease and cerebrovascular disease. Because the underlying pathophysiological mechanism is the same, coronary artery disease and cerebrovascular disease frequently coexist. Transesophageal echocardiography (TEE) is routinely done in patients with ischemic stroke to exclude possible cardiac sources of cerebral embolism. Since the introduction of multiplane transesophageal transducers, it has become easier to visualize the proximal coronary arteries during transesophageal examinations. We report three cases in which routine TEE for ischemic stroke revealed significant coronary artery disease that was not previously suspected. In one patient, the stroke was so severe that further evaluation of the coronary artery disease was not deemed useful. The other two patients underwent coronary angiography based on the echocardiographic findings, confirming the lesions noted on the echocardiogram. Subsequently, both patients were successfully revascularized: one by percutaneous transluminal coronary angioplasty and the other by coronary artery bypass graft surgery. We conclude that the examination of coronary arteries during routine TEE for ischemic stroke may become a useful screening tool for the detection of coexisting, asymptomatic, significant proximal coronary artery disease.

We report the first case of echocardiographically detected Lambl's excrescences on the pulmonary valve in a 72-year-old man who was referred for transesophageal echocardiography as a part of an evaluation for ischemic stroke. A total of four excrescences were noted on the arterial aspect of the pulmonary valve; two of them were on the anterior cusp, one was on the left cusp, and one was on the right cusp. The excrescence on the left cusp was the largest, measuring 5 mm in length. These valvular strands (Lambl's excrescences) represented an incidental finding and were not associated with any disease process.

The present study demonstrates the feasibility of delineating the carotid bulb and the proximal portions of the left external and left internal carotid arteries during transesophageal examination. This was accomplished by slowly and carefully withdrawing the probe from the esophagus into the pharynx.

In the present study, we report our experience of using three-dimensional reconstruction of transesophageal two-dimensional echocardiographic images in the assessment of aortic dissection (22 patients), aortic rupture (1 patient), aortic aneurysm without dissection (2 patients), and aortic tumor (1 patient).

Three-dimensional echocardiographic findings in cor triatriatum sinister (sinistrum), cor triatriatum dexter, mitral supravalvular membrane, and atrial baffle are presented.

We present the transesophageal echocardiographic findings in two adult patients with right-sided aortic arch: one without dissection and the other with traumatic aortic injury (dissection). In both patients, the branching pattern was the left common carotid artery and then the right common carotid artery, followed by the right and left subclavian arteries. The technique for the diagnosis of this anomaly and the identification of adjacent vascular structures using contrast echocardiography is described. Three-dimensional reconstruction of the aortic arch also was performed in both patients.

We describe the technique for identification of innominate veins, azygos vein, and left subclavian and internal jugular veins during transesophageal echocardiography. Validation was provided with contrast echocardiography.

Contrast transesophageal echocardiography was found useful in diagnosing combined interatrial and intrapulmonary right-to-left shunts in a patient presenting with orthodeoxia. This was done by separately examining the pulmonary veins and the interatrial septum during intravenous normal saline injections.

This preliminary experimental study demonstrates the potential usefulness of harmonic power Doppler imaging in producing left ventricular myocardial opacification and demonstrating intramyocardial coronary vessels during contrast echocardiography using Levovist, a saccharide-based contrast agent. The contrast effect was most dramatic when a vasodilator such as dipyridamole or nitroglycerin was used in conjunction with contrast injections of Levovist. No significant myocardial opacification was noted with B-mode harmonic imaging alone.