Near-field Artifacts Research Articles

Defect data image enhancement method based on all-focus imaging algorithm

When the total focus imaging (TFM) algorithm is oriented to multi-layer media, the energy attenuation of the sound beam in the wedge coupling model results in a decrease in detection energy and imaging reliability. In this paper, a new defect data image enhancement method is proposed to calibrate the full-focus imaging model: the attenuation coefficients of different emission-received acoustic beams in the coupled model were measured by the plexiglass reflection method, and the whole matrix captured data were reconstructed. To enhance the image of defect data, multi-threshold fusion is proposed to eliminate the artifacts in the imaging region, especially the noise artifacts in the near field region. Experimental results show that compared with the traditional full-focus imaging algorithm, the self-built algorithm model proposed in this paper greatly improves the energy attenuation problem at the defect with large deflection angle. Especially in the range of excellent detection results, the energy uniformity of the defect is significantly improved, which has a certain inhibitory effect on the artifacts near the defect. The subsequent artifact elimination work improved the defect characterization ability and image signal-to-noise ratio of fully focused images while the effect of near-field artifact elimination was significant.

A coded aperture microscope for X-ray fluorescence full-field imaging.

The design and construction of an instrument for full-field imaging of the X-ray fluorescence emitted by a fully illuminated sample are presented. The aim is to produce an X-ray microscope with a few micrometers spatial resolution, which does not need to scan the sample. Since the fluorescence from a spatially inhomogeneous sample may contain many fluorescence lines, the optic which will provide the magnification of the emissions must be achromatic, i.e. its optical properties must be energy-independent. The only optics which fulfill this requirement in the X-ray regime are mirrors and pinholes. The throughput of a simple pinhole is very low, so the concept of coded apertures is an attractive extension which improves the throughput by having many pinholes, and retains the achromatic property. Modified uniformly redundant arrays (MURAs) with 10 µm openings and 50% open area have been fabricated using gold in a lithographic technique, fabricated on a 1 µm-thick silicon nitride membrane. The gold is 25 µm thick, offering good contrast up to 20 keV. The silicon nitride is transparent down into the soft X-ray region. MURAs with various orders, from 19 up to 73, as well as their respective negative (a mask where open and closed positions are inversed compared with the original mask), have been made. Having both signs of mask will reduce near-field artifacts and make it possible to correct for any lack of contrast.

Single-Energy Retrospective Metal Artifact Reduction Using Adaptive Thresholding for Metal Implants in the Abdomen and Pelvis.

To assess impact of single-energy metal artifact reduction (SEMAR) algorithm utilizing retrospective adaptive thresholding in reducing metal artifacts in the abdomen and pelvis. In this prospective institutional review board-approved, Health Insurance Portability and Accountability Act-compliant study, 90 patients with various metals (n = 97) on computed tomography of abdomen and pelvis (Canon Medical, Aquilion ONE and PRIME) scanned 07/2017-09/2018 with SEMAR retrospectively applied were included. Density was measured in the near and far field to the metals. Density standard deviation (SD), representing artifact severity, was compared with and without SEMAR applied. Two trained human observers independently evaluated severity of artifacts on a five-point scale (0, no artifact; 5, severe artifact). The SEMAR significantly decreased artifact severity in the near field of high-density metal implants (SD of 204 ± 101HU without vs. 66 ± 40HU with SEMAR, P < 0.001). In the far field, the artifact severity was similar (40 ± 31HU without vs. 36 ± 27HU with SEMAR, P = 0.41). Artifact severity was decreased adjacent to low-density metal in the near field (SD of 86 ± 56HU without vs 49 ± 30HU with SEMAR, P < 0.001). In the far field to the low-density metals artifact severity was similar (33 ± 29HU without vs. 31 ± 27HU with SEMAR, P = 0.79). Subjectively, artifacts severity decreased for high-density metals in near field by 1.3 ± 1.0, and in far field by 0.7 ± 0.7 and for low-density metals in the near field by 0.7 ± 1.0, far field 0.4 ± 0.5, all P < 0.05. The SEMAR retrospective algorithm with adaptive thresholding subjectively and objectively reduced near-field artifacts generated by high- and low-density metals.

Near-field artifacts reduction in coded aperture push-broom Compton scatter imaging

Recently, we have devised a novel method called coded aperture push-broom Compton scatter imaging (CAPCSI) to improve the use of backscattered X-rays. Based on a correlation algorithm, near-field artifacts are obvious in the CAPCSI, although they could be reduced partially by averaging dual acquisitions of a mask and an antimask. In this paper, we introduce a maximum-likelihood expectation–maximization (MLEM) algorithm into the CAPCSI to improve the artifacts without dual acquisitions. First, a theoretical system matrix (SM) and a simulative SM were derived from the generation of near-field artifacts. Then, simulation for ideal sources was carried out to compare different algorithms of the correlation and the MLEM. Further, a CAPCSI prototype was set up to confirm the simulation. Because of the system nonuniformity, an experimental SM was derived in advance by a ray-driven way. Finally, imaging for character phantoms was presented. Preliminary results showed the MLEM performed much better for the point source and could obtain a cleaner background for complex objects than the correlation. In the simulation, the theoretical SM and the simulative SM were no essential difference. However, in the experiment, the experimental SM performed essentially better than the theoretical SM, because it took the near-field effects and the system nonuniformity into a comprehensive consideration. This work will help enhance the application potential of the CAPCSI.

Dual energy CT angiography: pros and cons of dual-energy metal artifact reduction algorithm in patients after endovascular aortic repair.

To evaluate the value of metal artifact reduction (MAR) post-processing and iodine MD images in fast kV-switching dual-energy computed tomography (DECT) in patients after endovascular aortic repair (EVAR). Twenty-four consecutive EVAR patients (age 76±9years, 7/24 (29%) with coils, 9/24 (37.5%) with 10 endoleaks) who underwent DECT angiography were included in this HIPAA-compliant, IRB-approved retrospective study. Monochromatic reconstructions included 55, 60, 65, 70, and 75keV with and without MAR and iodine MD images. Near field, far field, and vessel artifacts were assessed subjectively (1=none; 5=severe) and objectively by measuring noise and contrast-to-noise ratio. Visibility of endoleak was evaluated (1=optimal; 5=not visible). MAR objectively decreased artifacts from EVAR stents in the near field (60.7±25.4HU vs. 70.1±34.2; p=.002) and subjectively increased near field (3.2±0.9 vs. 2.8±0.6; p<.001), far field (2.2±0.6 vs. 1.6±0.6; p<.001), and vessel (3.1±1.1 vs. 2.5±0.9; p<.001) artifacts. Near-field artifacts from coils were reduced by the MAR objectively (72.4±24.8 vs. 182.7±57.3HU; p<.001) and subjectively (4.5±0.5 vs. 4.9±0.4; p=.02). CNR of standard reconstructions was optimal at 60keV (38.3±16.8). Reconstructions without MAR and iodine MD images provided improved endoleak visualization in 6/10 (60%) of cases (median 1 for both) compared to MAR (median 3) (p<0.001). However, MAR improved visualization in 1/10 (10%) cases due to endoleak location adjacent to a coil. DECT with MAR reduced artifacts from coils and improved endoleak visualization in 1/10 (10%) cases due to location adjacent to a coil. However, MAR impaired endoleak visualization in 6/10 (60%) cases and should be reviewed combined with 60keV standard reconstructions and iodine MD images.

Methods of improving the reconstructed image in systems with coded apertures

The application of systems with a coded aperture to obtain tomographic information has its pros and cons. The advantages of such systems are the high sensitivity and noise-immunity (compared, for example, with tomographs on the basis of gamma-cameras), the ability to focus on a given surface within the object, etc. The drawbacks include the near-field artifacts, which occur during the decoding of the source position and depend on the choice of a coding mask and geometric parameters of the system. In addition, the quality of the restored image is affected by the accuracy of the formation of the matrix of countability. The article studies the impact of the interaction of gamma-radiation with a substance on the quality of the formation of the matrix of countability and, as a result, on the quality of the restored image. It describes the method of formation of the correcting processing array and its use as a way to improve the restored image

Tailor-made right ventricular imaging

Right ventricular (RV) performance has a major role in the clinical status and prognosis of patients with congenital heart disease, especially in patients with a systemic right ventricle such as patients with congenitally corrected transposition of the great arteries (TGA) or with TGA corrected by a Mustard or Senning operation. Quantification of RV function is challenging for several reasons. Especially in echocardiography, the anterior position of the right ventricle in the chest causes near-field artifacts, which may preclude visualisation of the RV apex. Also, the complex morphology of the right ventricle makes an estimation of volumes based on two-dimensional (2D) measurements unreliable. Thirdly, exact delineation of the thin and highly trabecularised RV wall is difficult. Several modalities are available to assess RV function, of which cardiac magnetic resonance imaging (CMR) and echocardiography are most frequently used in clinical practice. CMR is considered the standard of reference, yet CMR is more costly and less widely available than echocardiography. RV volume measurements by 2D echocardiography correlate poorly with CMR [1]. Strain and strain-rate imaging provides an accurate, yet indirect, assessment of RV myocardial performance [2]. Three-dimensional echocardiography provides more accurate RV volume measurements than 2D echocardiography, yet compared with CMR it consistently underestimates RV volume [3–5]. This is probably due to incomplete depiction of the right ventricle. Also, in 3D echocardiography image quality was insufficient in approximately one fourth of patients [3–5]. CMR, on the other hand, is contraindicated in patients with a defibrillator or an MRI-unsafe pacemaker. Therefore, in the present issue, Winter and colleagues studied whether CT may be an alternative to CMR for the determination of RV volumes and function in TGA patients with a contraindication to CMR [6]. They studied 35 TGA patients; of these patients 20 underwent CMR to measure RV volumes and ejection fraction. In the remaining 15 patients, in whom CMR was contraindicated due to the presence of a pacemaker or defibrillator, RV volumes and ejection fraction were determined by CT. The authors found that the intra- and interobserver variability of RV volumes and ejection fraction measured with CT were higher compared with those with CMR. However, except for RV stroke volume these differences in variability were not statistically significant. Although the current study provides no direct intra-patient comparison between CMR and CT, previous studies demonstrated adequate correlation of RV volumes and function measured with 64-slice CT and those with CMR [7]. However, the more limited temporal resolution of 16-slice CT resulted in a systemic over-estimation of RV end-systolic volume [8]. As also addressed by Winters et al., CT is associated with radiation and iodine contrast material. The radiation dose of 14 mSv in the current study is substantial, especially for relatively young patients who are likely to receive additional examinations and treatments associated with radiation. In a 20-year-old subject, a radiation dose of 14 mSv confers an approximately 0.2 % (men) to 0.5 % (women) lifetime attributable risk of cancer [9]. The risk of cancer associated with a radiation dose of 14 mSv is 1.8 (men) to 3.2 (women) times higher for a 20-year-old subject compared with a 60-year-old subject of the same sex [9]. As discussed in more detail by Winters et al., presumed pacemaker- and defibrillator-related contraindications are predominantly theoretical and further research addressing CMR compatibility is warranted. MRI-safe pacemakers may prove valuable in patients with congenital heart disease. However, leads in the right ventricle may yield substantial artifacts in both CT and MRI, although current studies do not report preclusion of accurate RV measurements with CT in patients with a pacemaker. Obviously, for those patients depending on CT for RV imaging, strategies to reduce radiation dose are warranted. Dose-modulation protocols, in which tube current is reduced during less essential phases of the cardiac cycle, may reduce the radiation dose as has been demonstrated for retrospectively gated CT coronary angiography. Also, technical advances in newer generation CT scanners, such as more detector rows to enable scanning of the entire heart within one gantry rotation and improved detector sensitivity, may lead to a further reduction in radiation dose. Also, the amount of iodine contrast may be reduced with dual-energy scanners, as was recently shown for CT pulmonary angiography [10]. On the positive side, CT angiography can visualise the pulmonary arteries and aorta more accurately than CMR, which may prove valuable in clinical decision making in TGA patients. As supported by the study by Winters et al., a tailor-made approach for the individual patient is essential. Currently, in our opinion, CMR and 3D echocardiography remain the modalities of choice for RV imaging. However, in patients with contraindications to CMR and poor echocardiographic image quality, CT seems a valid alternative. Future technological advances may reduce the health risks associated with CT, while CT angiography provides potentially valuable additional information.

Near-field artifacts in tip-enhanced Raman spectroscopy

We demonstrate that near-field optical interactions encountered in tip-enhanced Raman spectroscopy (TERS) imaging of a nano-object can result in enhanced light scattering that is not caused by localized plasmonic excitations. The true TERS signal is shown to scale with the tip size; however, other tip-related artifacts can lead to spatial variations in Rayleigh and Raman scattering below the diffraction limit with decay lengths up to 250 nm. Such artifacts have been attributed to multiple scattering events involving the tip shaft; experimental considerations to alleviate these near-field artifacts and anomalous TERS signals are also discussed.

Optimization of a phased-array transducer for multiple harmonic imaging in medical applications: frequency and topology

Second-harmonic imaging is currently one of the standards in commercial echographic systems for diagnosis, because of its high spatial resolution and low sensitivity to clutter and near-field artifacts. The use of nonlinear phenomena mirrors is a great set of solutions to improve echographic image resolution. To further enhance the resolution and image quality, the combination of the 3rd to 5th harmonics--dubbed the superharmonics--could be used. However, this requires a bandwidth exceeding that of conventional transducers. A promising solution features a phased-array design with interleaved low- and high-frequency elements for transmission and reception, respectively. Because the amplitude of the backscattered higher harmonics at the transducer surface is relatively low, it is highly desirable to increase the sensitivity in reception. Therefore, we investigated the optimization of the number of elements in the receiving aperture as well as their arrangement (topology). A variety of configurations was considered, including one transmit element for each receive element (1/2) up to one transmit for 7 receive elements (1/8). The topologies are assessed based on the ratio of the harmonic peak pressures in the main and grating lobes. Further, the higher harmonic level is maximized by optimization of the center frequency of the transmitted pulse. The achievable SNR for a specific application is a compromise between the frequency-dependent attenuation and nonlinearity at a required penetration depth. To calculate the SNR of the complete imaging chain, we use an approach analogous to the sonar equation used in underwater acoustics. The generated harmonic pressure fields caused by nonlinear wave propagation were modeled with the iterative nonlinear contrast source (INCS) method, the KZK, or the Burger's equation. The optimal topology for superharmonic imaging was an interleaved design with 1 transmit element per 6 receive elements. It improves the SNR by ~5 dB compared with the interleaved (1/2) design reported in literature. The optimal transmit frequency for superharmonic echocardiography was found to be 1.0 to 1.2 MHz. For superharmonic abdominal imaging this frequency was found to be 1.7 to 1.9 MHz. For 2nd-harmonic echocardiography, the optimal transmit frequency of 1.8 MHz reported in the literature was corroborated with our simulation results.

Super-harmonic imaging: development of an interleaved phased-array transducer

For several years, the standard in ultrasound imaging has been second-harmonic imaging. A new imaging technique dubbed "super-harmonic imaging" (SHI) was recently proposed. It takes advantage of the higher - third to fifth - harmonics arising from nonlinear propagation or ultrasound-contrast-agent (UCA) response. Next to its better suppression of near-field artifacts, tissue SHI is expected to improve axial and lateral resolutions resulting in clearer images than second-harmonic imaging. When SHI is used in combination with UCAs, a better contrast-to-tissue ratio can be obtained. The use of SHI implies a large dynamic range and requires a sufficiently sensitive array over a frequency range from the transmission frequency up to its fifth harmonic (bandwidth > 130%). In this paper, we present the characteristics and performance of a new interleaved dual frequency array built chiefly for SHI. We report the rationale behind the design choice, frequencies, aperture, and piezomaterials used. The array is efficient both in transmission and reception with well-behaved transfer functions and a combined -6-dB bandwidth of 144%. In addition, there is virtually no contamination of the harmonic components by spurious transducer transmission, due to low element-to-element crosstalk (< 30 dB) and a low transmission efficiency of the odd harmonics (< 46 dB). The interleaved array presented in this article possesses ideal characteristics for SHI and is suitable for other methods like second-harmonic, subharmonic, and second-order ultrasound field (SURF) imaging.

Diagnosis and Management of Unilateral Third-Trimester Hydrocephalus: A Multidisciplinary Approach

Hydrocephalus is a pathological increase in cerebrospinal fluid. This condition may occur when production exceeds absorption. Prior reports describe prenatally diagnosed unilateral hydrocephalus with varying outcomes depending on underlying brain abnormalities, karyotypic abnormalities, and infection. Prenatal ultrasound is a valuable diagnostic tool in the identification of hydrocephalus. Obstacles such as near-field artifact, additional intracranial abnormalities, fetal positioning, and maternal habitus often make the diagnosis difficult. Antenatal diagnosis is important for emotional preparation and for transfer to a tertiary center where appropriate facilities and subspecialists are available. We present a case of right-sided hydrocephalus and mild left-sided ventriculomegaly diagnosed in the third trimester. Fetal brain magnetic resonance imaging confirmed the sonographic diagnosis, which allowed the multidisciplinary fetal team to meet with the patient and formulate a management plan prior to delivery.

Approaches to eliminate near field artifact of MURA

Since the coded aperture technique has been successfully applied on X-ray imaging space telescopes, attentions of its development have also been cast on the application in medical imaging, for it has a very tempting quality to greatly enhance the detection sensitivity without gravely lowering the spacial resolution. But when the coded aperture technique is applied to image a nearby object, the so called ``near-field artifact'' comes up, that is, the reconstructed image has a sort of distortion. Among types of coded apertures the MURA (Modified Uniformly Redundant Array) is one of the most discussed. Roberto Arrcosi came up with the solution to remove the artifacts utilizing mask and antimask. In this article we present two ways to eliminate the second order aberration based on his work.

Aperture collimation correction and maximum-likelihood image reconstruction for near-field coded aperture imaging of single photon emission computerized tomography

Coded aperture (CA) imaging originally developed in X-ray astronomy has not been widely used in nuclear medicine due to the decoding complexity of near-field CA images. In this paper, we present a near-field CA imaging technique and image reconstruction method for high sensitivity and high resolution single photon emission computerized tomography (SPECT). Our approach makes three contributions. First, a correction method for the aperture collimation effect is used to eliminate the near-field artifacts without dual acquisitions of mask and anti-mask images. Second, a maximum-likelihood expectation-maximization (MLEM) deconvolution method is used to restore CA images. Finally, a new MLEM-based algorithm is used to partially reconstruct three-dimensional (3-D) objects from a single projection of CA images. Experiments conducted using a dual-head SPECT system equipped with a parallel-hole collimator and a CA module show a tenfold increase in count sensitivity and significant improvement in image resolution with CA collimation as compared to parallel-hole collimation. Experiments conducted using the same dual-head SPECT system equipped with a pinhole collimator show that when the object is closer to the pinhole collimator the CA image resolution is only slightly inferior to the pinhole collimated image. We found that the MLEM deconvolution method provides an inherent nonnegativity constraint on pixel values and remarkably reduces background activities of CA images. The MLEM reconstruction algorithm for CA images is capable of reconstructing 3-D objects from a single projection and can be potentially extended to full 3-D SPECT reconstruction for CA images.

Computationally efficient noise reduction filter for enhancement of ultrasound images

In ultrasound imaging, acquired images are corrupted by slowly varying multiplicative non-uniformity. When the image is corrected for non-uniformity alone, noise in the dark regions of the original image becomes multiplicatively enhanced, thereby providing an unnatural look to the image. A pre-filtering technique is used to reduce noise in ultrasound pixel images by shrinking initial image data and processing the shrunken image with known segmentation-based filtering techniques that identify and differentially process structures within the image. The segmentation is based on both gradient threshold and the distance from the near field of the ultrasound image. This modification selectively suppresses near-field artifacts. After processing, the shrunken image is enlarged to the dimensions of the initial data and then blended with the initial image to form the final image. During blending, a small predetermined fraction of intensity-dependent, uniform random noise is added to the non-structure region pixels whose intensities are above a pre-specified intensity threshold, to mitigate ultrasound speckles while leaving non-echogenic regions undisturbed.

Optimal coded aperture patterns for improved SNR in nuclear medicine imaging

During a Nuclear Medicine project that called for the optimal design of a coded aperture we found that low-throughput masks do not always provide a Signal-to-Noise Ratio (SNR) advantage. In this paper, we present the simulations of the performance of some coded aperture patterns chosen from different families and compare the results with theoretical predictions. A general expression for the SNR and its particular form for different patterns are provided. The choice of the optimal pattern family is discussed with reference to the characteristics of the object to be imaged and in light of the effect of near-field artifacts. No-Two-Holes-Touching (NTHT) arrays based on Modified Uniformly Redundant Arrays (MURAs) proved to offer the best compromise between SNR performance and practical fabrication constraints.

Near-field artifact reduction in planar coded aperture imaging

Coded apertures for imaging problems are typically based on arrays having perfect cross-correlation properties. These arrays, however, guarantee a perfect point-spread function in far-field applications only. When these arrays are used in the near-field, artifacts arise. We present a mathematical derivation capable of predicting the shape of such artifacts. The theory shows that methods used in the past to compensate for the effects of background nonuniformities in far-field problems are also effective in reducing near-field artifacts. The case study of a nuclear medicine problem is presented to show good agreement of simulation and experimental results with mathematical predictions.

Factors affecting image quality and diagnostic efficacy in abdominal sonography: a prospective study of 140 patients.

A study was undertaken to evaluate the limitations of abdominal sonography in a group of predominantly elderly patients. In the majority of patients (98%) sonography, using 3.5 MHz and 5 MHz array transducers permitted visualization of the major abdominal organs with image quality sufficient for definitive diagnosis, but improved image quality would be desirable in 78% of this sample. Obesity and immobilization were associated with poor sonographic image quality. In 31 of the 45 (69%) poor image quality studies, no near-field artifacts (less than 3 cm depth) were observed. Obstacles in the acoustic path were noted in 77% of the poor image quality studies.

Improved echocardiographic detection and characterization of left ventricular apical thrombi with a 5.0 MHz short-focus transducer.

Transthoracic echocardiography is a frequently used technique for detecting ventricular thrombi. This study compares the usefulness of a 5.0 MHz short focal length transducer (5-short) with standard frequency (2.5 or 3.5 MHz) transducers for the detection of left ventricular thrombi. In addition, the effect of body habitus on study quality was evaluated. A consecutive series of 101 patients sent for echocardiographic imaging with the diagnosis of myocardial infarction, dilated cardiomyopathy, or recent suspected embolic event were imaged in the apical four-chamber, apical long-axis, and apical two-chamber views with a standard transducer and also with the 5-short. Out of this group, 16 apical thrombi were identified, six with the 5-short only, three with standard transducers only, and seven by both techniques. The areas of the seven thrombi detected by both transducers were consistently larger when measured on 5-short images compared with standard transducer images (4.6 +/- 2.3 vs 3.7 +/- 2.3 cm2, p = 0.02). In the three studies positive only with the standard transducers, the 5-short demonstrated only prominent trabeculae but no thrombus. The studies positive only with the 5-short had significantly smaller calculated thrombi areas than those visualized by the standard transducers (1.6 +/- 1.2 vs 4.2 +/- 2.1 cm2, p = 0.02). No thrombus was detected by either technique in a normally contracting left ventricular apex. There were significantly fewer studies having near-field artifact when performed by the 5-short compared with those performed with standard transducers (14/101 vs 40/101, p = 0.00004).(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasonic Myocardial Tissue Characterization in the Operating Room: Initial Results Using Transesophageal Echocardiography

Ultrasonic tissue characterization provides quantitative assessment of myocardial function and viability. We have previously reported that normal myocardium is characterized by a diastolic-to-systolic cyclic variation of integrated backscatter (IB), whereas ischemic myocardium exhibits blunting of this pattern. To define the applicability of this measurement to characterize the left ventricular myocardium in the operating room, we studied 26 consecutive patients undergoing open heart surgery (12 coronary artery bypass graft, 13 valvular, 1 other) with 5 MHz transesophageal echocardiography. Images of the left ventricle were obtained in the short-axis plane (papillary muscle level) before cardiopulmonary bypass. M-mode acquisition of myocardial IB was attempted from the anterior and inferior segments in each patient. The cyclic variation of IB was measured in at least two consecutive cycles in addition to a qualitative assessment of wall motion. Quantitative measurement of IB was possible in 39/52 (75%) myocardial segments. Cyclic variation of IB averaged 5.7 +/- 1.4 dB (SD) in segments with normal wall motion (n = 25); no difference was noted in the cyclic variation of IB among anterior or inferior walls. Hypokinetic segments demonstrated significant reduction of the cyclic variation (3.8 +/- 1.8 dB; p less than 0.001). Difficulty with obtaining myocardial IB was related to near-field artifact or lateral displacement of the left ventricular wall during systole. Transesophageal echocardiography holds promise for the evaluation of myocardial function and its preservation during cardiac surgery.