3D transesophageal echocardiography: a review of recent literature 2007–2009

Three-dimensional transoesophageal echocardiography: how to use and when to use-a clinical consensus statement from the European Association of Cardiovascular Imaging of the European Society of Cardiology

Three-dimensional transoesophageal echocardiography (3D TOE) has been rapidly developed in the last 15 years. Currently, 3D TOE is particularly useful as an additional imaging modality for the cardiac echocardiographers in the echo-lab, for cardiac interventionalists as a tool to guide complex catheter-based procedures cardiac, for surgeons to plan surgical strategies, and for cardiac anaesthesiologists and/or cardiologists, to assess intra-operative results. The authors of this document believe that acquiring 3D data set should become a 'standard part' of the TOE examination. This document provides (i) a basic understanding of the physic of 3D TOE technology which enables the echocardiographer to obtain new skills necessary to acquire, manipulate, and interpret 3D data sets, (ii) a description of valvular pathologies, and (iii) a description of non-valvular pathologies in which 3D TOE has shown to be a diagnostic tool particularly valuable. This document has a new format: instead of figures randomly positioned through the text, it has been organized in tables which include figures. We believe that this arrangement makes easier the lecture by clinical cardiologists and practising echocardiographers.

Bend-insensitive fiber optic ultrasonic tracking probe for cardiovascular interventions

BACKGROUND

Transesophageal echocardiography (TEE) is widely used to guide medical device placement in minimally invasive cardiovascular procedures. However, visualization of the device tip with TEE can be challenging. Ultrasonic tracking, enabled by an integrated fiber optic ultrasound sensor (FOUS) that receives transmissions from the TEE probe, is very well suited to improving device localization in this context. The problem addressed in this study is that tight deflections of devices such as a steerable guide catheter can result in bending of the FOUS beyond its specifications and a corresponding loss of ultrasound sensitivity.

PURPOSE

A bend-insensitive FOUS was developed, and its utility with ultrasonic tracking of a steerable tip during TEE-based image guidance was demonstrated.

METHODS

Fiberoptic ultrasound sensors were fabricated using both standard and bend insensitive single mode fibers and subjected to static bending at the distal end. The interference transfer function and ultrasound sensitivities were compared for both types of FOUS. The bend-insensitive FOUS was integrated within a steerable guide catheter, which served as an exemplar device; the signal-to-noise ratio (SNR) of tracking signals from the catheter tip with a straight and a fully deflected distal end were measured in a cardiac ultrasound phantom for over 100 frames.

RESULTS

With tight bending at the distal end (bend radius < 10 mm), the standard FOUS experienced a complete loss of US sensitivity due to high attenuation in the fiber, whereas the bend-insensitive FOUS had largely unchanged performance, with a SNR of 47.7 for straight fiber and a SNR of 36.8 at a bend radius of 3.0 mm. When integrated into the steerable guide catheter, the mean SNRs of the ultrasonic tracking signals recorded with the catheter in a cardiac phantom were similar for straight and fully deflected distal ends: 195 and 163.

CONCLUSION

The FOUS fabricated from bend-insensitive fiber overcomes the bend restrictions associated with the FOUS fabricated from standard single mode fiber, thereby enabling its use in ultrasonic tracking in a wide range of cardiovascular devices.

Acoustic characterization of a miniature matrix transducer for pediatric 3D transesophageal echocardiography

This paper presents the design, fabrication and characterization of a miniature PZT-on-CMOS matrix transducer for real-time pediatric 3-dimensional (3D) transesophageal echocardiography (TEE). This 3D TEE probe consists of a 32 × 32 array of PZT elements integrated on top of an Application Specific Integrated Circuit (ASIC). We propose a partitioned transmit/receive array architecture wherein the 8 × 8 transmitter elements, located at the centre of the array, are directly wired out and the remaining receive elements are grouped into 96 sub-arrays of 3 × 3 elements. The echoes received by these sub-groups are locally processed by micro-beamformer circuits in the ASIC that allow pre-steering up to ±37°. The PZT-on-CMOS matrix transducer has been characterized acoustically and has a centre frequency of 5.8 MHz, -6 dB bandwidth of 67%, a transmit efficiency of 6 kPa/V at 30 mm, and a receive dynamic range of 85 dB with minimum and maximum detectable pressures of 5 Pa and 84 kPa respectively. The properties are very suitable for a miniature pediatric real-time 3D TEE probe.

Intraoperative three-dimensional transesophageal echocardiography for evaluating an unusual structure in the left ventricular outflow tract: a case report

Intraoperative three-dimensional (3D) transesophageal echocardiography (TEE) facilitates an understanding of the complex cardiac pathology that is not fully delineated in a two-dimensional (2D) echocardiographic evaluation, and it suggests earlier and more precise surgical planning and intraoperative decision making. In the present case, the intraoperative 2D-TEE midesophageal long-axis view indicated a significant narrowing of the left ventricular outflow tract (LVOT) area by a band-like structure that vertically traversed the middle of the LVOT and connected to the anterior mitral leaflet base and the interventricular septum. However, additional 3D-TEE images of the LVOT and their cropped and rendered 2D images showed that web-like tissue, which presumably had grown around the patch closure from a previous atrioventricular septal defect, was obstructing the LVOT partially.

[Update on pediatric cardiology and congenital heart disease: imaging techniques, pulmonary arterial hypertension, hybrid treatment, and surgical treatment]

This article contains a review of the most significant contributions to pediatric cardiology and congenital heart disease reported in publications between September 2009 and August 2010. The review focuses on imaging techniques, new treatment for pulmonary arterial hypertension in pediatric patients, and therapy in general (e.g. hybrid treatment and surgical treatment). With regard to imaging techniques, the review highlights the increasing application of congenital heart disease diagnosis during fetal life, the introduction of new echocardiographic techniques (e.g. tissue Doppler imaging, two-dimensional speckle-tracking imaging and three-dimensional echocardiography) into routine clinical practice, and the growing use of cardiac CT and magnetic resonance imaging in diagnosis and the assessment of cardiac function, respectively. The role played by cardiac interventions continues to increase and cardiac surgery is becoming more advanced and has, in some cases, been combined with hybrid techniques. However, there are still a number of controversial issues in cardiac surgery that have not yet been resolved, such as whether or not fenestration should be used with Fontan surgery, the optimum type of correction for hypoplastic left heart syndrome, and the best conduit for pulmonary artery replacement.

Transoesophageal echocardiography in the dog

Transoesophageal echocardiography (TEE) allows imaging of the heart through the oesophagus using a special transducer mounted on a modified endoscope. The proximity to the heart and minimal intervening structures enables the acquisition of high-resolution images that are consistently superior to routine transthoracic echocardiography and optimal imaging of the heart base anatomy and related structures. TEE provides high-quality real-time imaging free of ionizing radiation, making it an ideal instrument not only for diagnostic purposes, but also for monitoring surgical or minimally invasive cardiac procedures, non-cardiac procedures and critical cases in the intensive care unit. In human medicine, TEE is routinely used in these settings. In veterinary medicine, TEE is increasingly used in referral centres, especially for perioperative assessment and guidance of catheter-based cardiovascular procedures, such as patent ductus arteriosus, balloon valvuloplasty, and atrial and ventricular septal defect occlusion with vascular devices. TEE can also aid in heartworm retrieval procedures. The purpose of this paper is to review the current uses of TEE in veterinary medicine, focusing on technique, indications and complications.

Utilizing three-dimensional echocardiography in cardioscopic left ventricular myxoma resection

A 31-year-old female presented with right-sided stroke symptoms. She was found to have a left ventricular (LV) mass on transthoracic echocardiogram. Subsequent transesophageal echocardiogram (TEE) with concurrent three-dimensional (3D) imaging revealed a 2-cm mobile mass, suspicious for a myxoma, attached to the anteroseptal LV wall. Given the size and location of the mass seen on the 3D images, the cardiothoracic surgeons chose to avoid resection via aortotomy or ventriculotomy and instead performed video-assisted cardioscopic resection of the LV mass via left atriotomy. The mass was successfully removed, and pathology confirmed that it was a myxoma.

Repairing Interatrial Septal Defects From the Operating Room to the Cardiac Catheterization Laboratory: 2D or Not 2D?

Uncorrected congenital interatrial septal defect can be found in nearly a third of all adults and are associated with significant morbidity, including pulmonary hypertension, right-heart failure, atrial arrhythmias, and paradoxical embolic stroke. With advancing technology, percutaneous closure of atrial septal defects has become a viable alternative to open surgical repair. In this review, the authors provide 3 examples in which 3-dimensional interventional transesophageal echocardiogram effectively provided more precise visualization of the dynamic surface and geometry of the atrial septum and related structures than 2-dimensional TEE, permitting accurate sizing and repair of the defects.

Role of transesophageal echocardiography in the management of pediatric patients with congenital heart disease

Transesophageal echocardiography (TEE) has become a critical diagnostic and perioperative management tool for patients with congenital heart disease (CHD) undergoing cardiac and noncardiac surgical procedures. This review highlights the role of TEE in routine management of pediatric cardiac patient population with focus on indications, views, applications and technological advances.

The Use of Ultrasound to Guide Interventions: From Bench to Bedside and Back Again

The ultrasound machine was originally devised as a diagnostic tool to help evaluate heart structure and function. With recent advances in ultrasound, including live 3D ultrasound, its potential to guide interventions within the heart has increasingly been recognized. Cardiologists have adapted this technology and have now published guidelines on the use of ultrasound to guide interventional procedures. Anesthesiologists have also used ultrasound with much success in cardiac operating rooms (ORs) to guide cannula placement and, to a limited extent, interventions. The focus of this article is a review of the author’s work on ultrasound and virtual reality—guided cardiac interventions, both in the research laboratory and in the OR.