ECG Gating Research Articles

Free breathing whole-heart 3D CINE MRI with self-gated Cartesian trajectory

PurposeTo present a method that uses a novel free-running self-gated acquisition to achieve isotropic resolution in whole heart 3D Cartesian cardiac CINE MRI. Material and methods3D cardiac CINE MRI using navigator gating results in long acquisition times. Recently, several frameworks based on self-gated non-Cartesian trajectories have been proposed to accelerate this acquisition. However, non-Cartesian reconstructions are computationally expensive due to gridding, particularly in 3D. In this work, we propose a novel highly efficient self-gated Cartesian approach for 3D cardiac CINE MRI. Acquisition is performed using CArtesian trajectory with Spiral PRofile ordering and Tiny golden angle step for eddy current reduction (so called here CASPR-Tiger). Data is acquired continuously under free breathing (retrospective ECG gating, no preparation pulses interruption) for 4–5min and 4D whole-heart volumes (3D+cardiac phases) with isotropic spatial resolution are reconstructed from all available data using a soft gating technique combined with temporal total variation (TV) constrained iterative SENSE reconstruction. ResultsFor data acquired on eight healthy subjects and three patients, the reconstructed images using the proposed method had good contrast and spatio-temporal variations, correctly recovering diastolic and systolic cardiac phases. Non-significant differences (P>0.05) were observed in cardiac functional measurements obtained with proposed 3D approach and gold standard 2D multi-slice breath-hold acquisition. ConclusionThe proposed approach enables isotropic 3D whole heart Cartesian cardiac CINE MRI in 4 to 5min free breathing acquisition.

A sparse Bayesian representation for super-resolution of cardiac MR images

High-quality cardiac magnetic resonance (CMR) images can be hardly obtained when intrinsic noise sources are present, namely heart and breathing movements. Yet heart images may be acquired in real time, the image quality is really limited and most sequences use ECG gating to capture images at each stage of the cardiac cycle during several heart beats. This paper presents a novel super-resolution algorithm that improves the cardiac image quality using a sparse Bayesian approach. The high-resolution version of the cardiac image is constructed by combining the information of the low-resolution series –observations from different non-orthogonal series composed of anisotropic voxels – with a prior distribution of the high-resolution local coefficients that enforces sparsity. In addition, a global prior, extracted from the observed data, regularizes the solution. Quantitative and qualitative validations were performed in synthetic and real images w.r.t to a baseline, showing an average increment between 2.8 and 3.2 dB in the Peak Signal-to-Noise Ratio (PSNR), between 1.8% and 2.6% in the Structural Similarity Index (SSIM) and 2.% to 4% in quality assessment (IL-NIQE). The obtained results demonstrated that the proposed method is able to accurately reconstruct a cardiac image, recovering the original shape with less artifacts and low noise.

Application of low dose radiation and low concentration contrast media in enhanced CT scans in children with congenital heart disease.

The aim of this study was to explore the feasibility of using low dose radiation and low concentration contrast media in enhanced CT examinations in children with congenital heart disease. Ninety patients with congenital heart disease were randomly divided into three groups of 30 patients each who underwent contrast-enhanced cardiac scans on a Discovery CT750 HD scanner. Group A received 270mgI/mL iodixanol, and group B received 320mgI/mL iodixanol contrast media and was scanned with prospective ECG triggering mode. Group C received 320mgI/mL iodixanol and was scanned with conventional retrospective ECG gating mode. The same weight-based contrast injection protocol was used for all three groups. Images were reconstructed using a 30% adaptive statistical iterative reconstruction (ASIR) algorithm and a 50% ASIR in groups A and B and a 30% ASIR in group C. The subjective and objective image quality evaluations, diagnostic accuracies, radiation doses and amounts of contrast media in the three groups were measured and compared. All images in the three groups met the diagnostic requirements, with the same diagnostic accuracy and image quality scores greater than 3 in a 4-point scoring system. However, ventricular enhancement and the objective noise, signal-to-noise ratio, contrast-to-noise ratio and subjective image quality scores in group C were better than those in groups A and B (all P<.001). The effective radiation dose in groups A and B was 84% lower than that in group C (P<.001); group A received the lowest contrast dose (14% lower than that of groups B and C). Enhanced CT scan images with low dose radiation and low concentration contrast media can meet the diagnostic requirements for examining children with congenital heart disease while reducing the potential risk of radiation damage and contrast-induced nephropathy.

Retinal microvascular diameter, a hypertension-related trait, in ECG-gated vs. non-gated images analyzed by IVAN and SIVA.

The diameters of the retinal microvasculature reflect intermediate target organ damage and predict adverse health outcomes. In view of the pulsatility of the cerebral blood flow and refinement of software used for off-line analysis, we assessed the repeatability of retinal microvascular diameters in ECG-gated vs. non-gated images using nonmydriatic retinal photographs (Canon Cr-DGi visualization system) postprocessed by IVAN (Vasculomatic ala Nicola, version 1.1) or SIVA (Singapore I Vessel Assessment, version 3.6). Using these algorithms, we determined the central retinal arteriolar (CRAE) and venular (CRVE) equivalents and their ratio (arteriole-to-venule ratio (AVR)). The estimates of CRAE (mean, 158.5 μm), CRVE (222.5 μm) and AVR (0.71) in 10 volunteers were unaffected (P⩾0.059) by ECG gating. We assessed intragrader repeatability by the Bland and Altman approach in 30 participants with non-gated images and 30 with ECG-gated photographs. Repeatability, which was expressed as the percentage of near maximal variability (4-s.d. range), did not improve with ECG gating. Using SIVA, CRAE and CRVE were systematically larger (P⩽0.031), and the AVR estimates were similar (P⩾0.15) compared with IVAN. The differences (IVAN-SIVA) averaged -5.4 μm for CRAE, -3.9 μm for CRVE and -0.012 for AVR in the non-gated images and -3.3 μm, -6.9 μm and 0.006, respectively, in the ECG-gated photographs. In conclusion, ECG gating does not affect estimates of the retinal microvascular diameters or improve intragrader repeatability. SIVA yields slightly but significantly larger estimates of the retinal arteriolar and venular diameters. Combining historical readings analyzed by IVAN with more recent readings by SIVA is possible only for AVR and is not recommended for either CRAE or CRVE.

Rigid and elastic registration for coronary artery IVUS images.

Intravascular ultrasound (IVUS) has been widely used in diagnosis and interventional treatment of cardiac vessel diseases. The coronary artery IVUS images are usually polluted by motion artifacts caused by cardiac motion, pulsatile blood and catheter twist during continuous pullback acquisition. Strategies for rigid and elastic registration of coronary artery IVUS studies are developed to suppress the longitudinal motion and misalignment between successive frames. Rigid registration is performed by searching for the optimal matching for each frame in other cycles based on the cyclic variation of gray-scale features. The image sequence is gated to properly identify the frames in each cardiac phase. Then, elastic registration between frames is achieved through an optimization algorithm based on thin plate spline (TPS) to correct the misalignment of successive slices. Experimental results with in vivo image data shows that the rigid registration performs better than the offline ECG gating. The elastic mapping relation between lumen contours in successive frames is smooth and continuous. The serrated vessel wall borders in longitudinal cuts are smoothed after rigid registration while image segmentation and feature extraction are required. The point-to-point correspondence between lumen contours detected from two matched frames is obtained with elastic registration.

32. Ultra-fast, low dose high-pitch (flash) versus prospectively gated coronary computed tomography angiography

Coronary computed tomography angiography (CTA) is increasingly being used for evaluation of coronary artery disease (CAD), but Radiation exposure still a major limitation of its use.We hypothesized that the high pitch spiral (FLASH) is superior to prospective (step and shoot (SAS)) ECG gating scan protocol, and associated with a low radiation exposure. The purpose of our study is to compare image quality and radiation exposure in a two group of patients undergoing CTA using a 256-slice dual source helical CT scanner with FLASH or SAS protocols.We randomized 162 patients referred for coronary CTA for either FLASH or SAS scanning protocols, subjective Image quality was graded based on a 4-point grading system (1: non diagnostic, 2: adequate, 3: good, 4: excellent). While Objective image quality was assessed using image signal, noise, and signal-to-noise ratio (SNR). The effective radiation dose was also estimated.The clinical and demographic characteristics of the patients in both groups were similar. We found that subjective image quality obtained with FLASH was superior to SAS (3.35 ± 0.6 vs. 2.82 ± 0.61 mSv; p ± 6.13 24.0 ± 6.8, p = 0.10), while the signal and SNR was significantly higher with FLASH Compared to SAS (469 ± 116 vs. 397 ± 106. P = ± 8.7 vs. 16.6 ± 7.7 mSv; p ± 0.4 mSv vs. 5.12 ± 1.8 mSv; p

TU‐H‐CAMPUS‐IeP2‐02: Four‐Dimensional Coronary Artery Visualization Based On Image Propagation

Purpose:4D visualization of coronary artery using X‐ray angiograms rotationally acquired on C‐arm has many valuable applications, like dynamic roadmapping. In this work we propose and validate a method to visualize 4D artery based on 3D coronary image propagation.Methods:After sorting the angiograms into different cardiac phases using nearest‐neighbor ECG gating, a high quality 3D coronary image was reconstructed at one phase using a motion‐compensated iterative reconstruction method. Then the reconstructed image was propagated to other cardiac phases by registering it to the angiograms of each phase (stage I registration). A third‐order B‐spline was used to model the vessel motion and the parameters were solved by maximizing the normalized correlation (NC) between the projections of the 3D image and the angiograms under the constraints of motion smoothness and volume preserving. Because the angiograms corresponding to one phase contain residual vessel motion and the registration method could only match the mean vessel morphology, morphological mismatch still existed between the propagated image and each angiogram. To obtain accurate vessel morphology according to each angiogram, we further registered the propagated image to each angiogram using the aforementioned registration method (stage II registration).Results:The proposed method was evaluated on angiograms simulated using 4D XCAT phantom. The reconstructed image at end‐diastolic phase (phase 0%) was consecutively propagated to end‐systolic phase (phase 40%) every 5%. After stage I registration, the mean distance between the propagated and ground truth vessel centerlines was decreased from 2.2±1.2 to 0.6±0.2 mm. The mean centerline distance was further decreased to 0.5±0.2 mm after the stage II registration.Conclusion:A 4D coronary artery visualization method based on image propagation was proposed. The experimental results show that accurate 4D morphology of coronary artery could be obtained using this method.This work was supported by the National Natural Science Foundation of China (61171005).

Diagnostic Yield of Triple-Rule-Out CT in an Emergency Setting.

The objective of the present study is to quantify the diagnostic yield of triple-rule-out (TRO) CT for the evaluation of acute chest pain in emergency department patients. All TRO CT studies performed at our institution from 2006 to 2015 were reviewed. Scans were performed on a 256-MDCT scanner, with the use of ECG gating and a biphasic contrast injection. Radiology reports were reviewed to identify diagnoses that could explain chest pain, including coronary and noncoronary diagnoses, and significant incidental findings that did not account for the patient's presentation. The total numbers of coronary and noncoronary diagnoses and incidental findings were calculated. Four of 1196 total cases that were identified were excluded from the study because of inadequate image quality. A total of 970 patients (81.4%) had a negative study result without a significant coronary or noncoronary diagnosis. A total of 139 patients (11.7%) had significant coronary artery disease (50% stenosis or greater). One hundred six patients (8.9%) had a noncoronary diagnosis that could explain chest pain (p < 0.02), most commonly pulmonary embolism (28 patients [2.3%]), aortic aneurysm (24 patients [2.0%]), or pneumonia (20 patients [1.7%]). Thirty cases (27.3%) of pulmonary embolism and aortic pathologic findings would not have been detected with coronary CT angiography because of unopacified right-side circulation or limited z-axis coverage. A total of 528 incidental findings not considered to explain chest pain were noted in 418 patients (35.1%). In 8.9% of patients, TRO CT detected a significant noncoronary diagnosis that could explain acute chest pain, including pathologic findings that would not be identified on dedicated coronary CT angiography.

Dataset of calcified plaque condition in the stenotic coronary artery lesion obtained using multidetector computed tomography to indicate the addition of rotational atherectomy during percutaneous coronary intervention.

Our data shows the regional coronary artery calcium scores (lesion CAC) on multidetector computed tomography (MDCT) and the cross-section imaging on MDCT angiography (CTA) in the target lesion of the patients with stable angina pectoris who were scheduled for percutaneous coronary intervention (PCI). CAC and CTA data were measured using a 128-slice scanner (Somatom Definition AS+; Siemens Medical Solutions, Forchheim, Germany) before PCI. CAC was measured in a non-contrast-enhanced scan and was quantified using the Calcium Score module of SYNAPSE VINCENT software (Fujifilm Co. Tokyo, Japan) and expressed in Agatston units. CTA were then continued with a contrast-enhanced ECG gating to measure the severity of the calcified plaque condition. We present that both CAC and CTA data are used as a benchmark to consider the addition of rotational atherectomy during PCI to severely calcified plaque lesions.

Morphology-matching-based R-wave detection for noise-robust ECG gating

Morphology-matching-based R-wave detection for noise-robust ECG gating

A comparison of real-time radial GRAPPA and standard cine imaging for the evaluation of cardiac function in children and young adults

Background Segmented balanced steady state free precession (bSSFP) cine imaging is the gold standard MRI technique for assessing ventricular systolic function. The image acquisition involves ECG gating and is ideally performed during breath-hold to reduce artifacts from myocardial and respiratory motion. Real-time radial imaging with parallel imaging technique GRAPPA reconstruction (radial GRAPPA) utilizes a radial data collection scheme in combination with a through-time k-space GRAPPA technique to achieve high acceleration rates. As it is acquired during free-breathing and is not ECG-gated, it has the potential to dramatically shorten cardiac functional imaging time. As radial GRAPPA has previously only been validated in adult patients, our purpose is to compare image quality between bSSFP and radial GRAPPA for evaluating cardiac function in children and young adults.

Abstract 16854: An Ungated, Rapid Rest/Stress Myocardial Perfusion Protocol is Useful for Detection of Coronary Artery Disease in Patients With Atrial Fibrillation

Introduction: In patients with atrial fibrillation, the diagnostic accuracy of standard, gated stress/rest perfusion cardiovascular magnetic resonance (CMR) for detection of coronary artery (CAD) disease remains uncertain. Here we investigated using instead an ungated approach with no ECG gating with a rapid rest/stress perfusion protocol to determine its accuracy for detection of CAD in this patient population. To overcome the potential issue of peri-infarct ischemia with a rest-first sequence, we gave very little time between rest and stress perfusion scans. Methods: 23 patients with atrial fibrillation (68 ± 13 years, 13 males and 10 females) underwent a very rapid rest/regadenoson stress perfusion imaging protocol and X-Ray angiography in this study. An ungated radial myocardial perfusion sequence was used (TR/TE = 2.2/1.2 msec, 3T, 20 rays/slice, 5 slices after each saturation pulse, ~2х2х8 mm). Rest/stress protocol was performed in the following order: rest image acquisition (0.05 mmol/kg gadoteridol), administration of regadenoson 0.4 mg intravenously (0.4 mg/5 mL) to induce hyperemia, 70 second wait, then stress image acquisition (0.075 mmol/kg gadoteridol). CMR perfusion images were interpreted by a blinded reader as normal or abnormal, without viewing cine or late gadolinium enhanced images, and also evaluated for quality (1 to 5, lowest to highest). Diagnostic accuracy was evaluated by comparison to X-Ray angiography: significant lesions were defined as stenosis &gt;70 % stenosis or functional flow reserve &lt;0.8. Results: 18 of the scans were negative and 5 were positive by angiography criteria. Sensitivity, specificity and accuracy for detection of CAD were 100%, 89% and 91%, respectively. Average scan time for imaging acquisition was 6.5 ± 4.0 minutes. Average image quality for both rest and stress perfusion images was 3.2 ± 0.9. Conclusions: An ungated myocardial perfusion sequence with rapid rest/regadenoson stress perfusion protocol addresses the concern of lingering hyperemia with regadenoson and problematic gating. This study suggests that assessment of myocardial perfusion with an ungated technique is an approach with high accuracy for detection of significant CAD in patients with atrial fibrillation.

Abstract 19548: Comparison of a Novel Four Dimensional CT Myocardial Strain Analyzing Technique With MRI, TTE, and Endomyocardial Biopsy

Introduction: Myocardial strain is a new indicator of myocardial characteristics and function, mainly evaluated by transthoracic echocardiography (TTE) or magnetic resonance imaging (MRI) techniques that rely on dynamic two dimensional images. Hypothesis: We hypothesized that utilizing the full capability of four dimensional (4D) volumetric 320 slice CT image data with retrospective ECG gating we could provide additional information on myocardial morphology, characteristics and function on Novel 4D CT myocardial stain analysis (developed with PhyZioDynamics, Zio). Method: We retrospectively analyzed ten subjects with various rare and un- typical myocardial diseases diagnosed by 320 slice CT using retrospective ECG gating and dose modulation. Some diagnoses were confirmed using MRI, TTE or endomyocardial biopsy (EMB). 4D CT myocardial strain analysis confirmed their diagnosis (see fig). Areas with maximum strain are colored red and decreasing strain, yellow, green, blue, and finally no color (=no strain). Results: Case 1 had a large, idiopathic fat deposit in the left ventricle (LV) that could be observed using enhanced CT with a low CT attenuation area. On 4D CT strain analysis, the fat deposit showed no strain. Case 2 had cardiac amyloidosis confirmed by EMB and Case 3 had type 2 hypertrophic cardiomyopathy (HCM). MRI showed late gadolinium enhancements (LGE) in both cases. At corresponding sites, no strain was observed by 4D CT. Other cases analyzed were dilated cardiomyopathy with focal LGE on MRI, subendocardial myocardial infarction with enlarged LV myocardium, etc. Conclusion: This is the first report worldwide of a 4D CT myocardial strain analyzing technique that utilizes full volumetric data. Our new technique uses ordinary cardiac CT data acquired with retrospective ECG gating, to provide detailed additional information on myocardial characteristics and function in addition to LV ejection fraction volume data and information on coronary arteries.

Automatic slice-alignment method in cardiac magnetic resonance imaging for evaluation of the right ventricle in patients with pulmonary hypertension

We propose a new automatic slice-alignment method, which enables right ventricular scan planning in addition to the left ventricular scan planning developed in our previous work, to simplify right ventricular cardiac scan planning and assess its accuracy and the clinical acceptability of the acquired imaging planes in the evaluation of patients with pulmonary hypertension. Steady-state free precession (SSFP) sequences covering the whole heart in the end-diastolic phase with ECG gating were used to acquire 2D axial multislice images. To realize right ventricular scan planning, two morphological feature points are added to be detected and a total of eight morphological features of the heart were extracted from these series of images, and six left ventricular planes and four right ventricular planes were calculated simultaneously based on the extracted features. The subjects were 33 patients (25 with chronic thromboembolic pulmonary hypertension and 8 with idiopathic pulmonary arterial hypertension). The four right ventricular reference planes including right ventricular short-axis, 4-chamber, 2-chamber, and 3-chamber images were evaluated. The acceptability of the acquired imaging planes was visually evaluated using a 4-point scale, and the angular differences between the results obtained by this method and by conventional manual annotation were measured for each view. The average visual scores were 3.9±0.4 for short-axis images, 3.8±0.4 for 4-chamber images, 3.8±0.4 for 2-chamber images, and 3.5±0.6 for 3-chamber images. The average angular differences were 8.7±5.3, 8.3±4.9, 8.1±4.8, and 7.9±5.3 degrees, respectively. The processing time was less than 2.5 seconds in all subjects. The proposed method, which enables right ventricular scan planning in addition to the left ventricular scan planning developed in our previous work, can provide clinically acceptable planes in a short time and is useful because special proficiency in performing cardiac MR for patients with right ventricles of various sizes and shapes is not required.

WE‐G‐207‐01: Motion‐Compensated Iterative Reconstruction of Coronary Artery Based On 3D/2D Deformable Image Registration

Purpose:The 3D reconstruction of coronary artery from x‐ray angiograms rotationally acquired on c‐arm is a challenging task because of the vessel motion. While ECG gated reconstruction have shown promising results, residual vessel motion exists because of imperfect gating or irregular motion, and affects the reconstruction quality. The purpose of this work is to propose and validate a new motion‐compensated reconstruction method to reduce the effect of residual vessel motion.Methods:The proposed method consisted of three main steps. First, a subset of angiograms were selected using nearest‐neighbor ECG gating and used to perform the initial reconstruction based on a L1 and total variation regularized iterative reconstruction method. Due to the residual vessel motion, the initial Result exhibited motion artifacts which hindered its clinical usage. Next, a novel 3D/2D registration method was proposed to estimate the vessel motion between the initial reconstruction and the vessel morphology corresponding to each angiogram. Finally, a regularized iterative reconstruction method with motion‐compensation was proposed to reconstruct the final Result.Results:The proposed method was evaluated using three groups of simulated ECG‐gated angiograms with increasing amount of residual vessel motion. The reconstruction results of the proposed method were quantitatively evaluated using Maximum Mean Overlap (MMO) and Relative Radius Error (RRE) metrics, where larger MMO value and smaller RRE value means a better reconstruction. The MMOs (ECG gated reconstruction vs. motion‐compensated reconstruction) for the three groups were (0.94, 0.87, 0.79) vs. (0.96, 0.93, 0.89); The RREs were (7.7, 15.6, 23.3) vs. (4.2, 4.3, 7.1). The reconstruction Result was comparable to that of state‐of‐the‐art method.Conclusion:We have developed and validated a motion‐compensated reconstruction method to handle the residual vessel motion which degrades the ECG gated reconstruction. The method could effectively estimate and compensate the vessel motion, and thus improve the reconstruction quality.

Seventy–Peak Kilovoltage High-Pitch Thoracic Aortic CT Angiography without ECG Gating: Evaluation of Image Quality and Radiation Dose

To assess the feasibility of 70-kVp high-pitch non-ECG-gated thoracic aortic computed tomography angiography (CTA) with 40-mL contrast agent compared to 100-kVp standard-pitch CTA with 60-mL contrast agent. Sixty-seven patients (51 men and 16 women; mean age, 55 ± 14 years) received non-ECG-gated aortic CTA at 70 kVp, high pitch of 3.4, and 40-mL contrast agent (group A, n = 31) or CTA at 100-kVp, pitch of 1.2, and 60-mL contrast agent (group B, n = 36). Iterative reconstruction was used in all patients. For image quality assessment, CTA images were evaluated on a three-point scale and signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated and compared. Furthermore, computed tomography (CT) dose index was recorded. Mean CT values and noise levels were higher in group A compared to group B (all P < .001), whereas SNR and CNR were lower than those in group B (all P < .001). Furthermore, the image quality of the aorta at the level of the diaphragm was lower in group A than that in group B (P < .05). However, image quality was graded as diagnostic in all patients, and motion artifacts of the aortic arch were significantly decreased in group A (P <.05). Interreader agreement was good or excellent for image quality assessment (k = 0.625-0.835). The 70-kVp CTA protocol, which allows dose reduction of 85%, was considered diagnostic in all instances by two readers. Our proposed thoracic aortic CTA protocol provides diagnostic information with substantial reduction of both radiation and contrast agent doses compared to standard-pitch CTA at 100 kVp.

Objective and subjective image quality with prospectively gated versus ECG-controlled tube current modulation using 256-slice computed tomographic angiography

IntroductionRadiation exposure is one of the major limitations of computed tomographic coronary angiography (CTA). The purpose of this study was to compare the objective and subjective image quality and radiation dose using prospective ECG gating (PGA) versus ECG-controlled tube current modulation (ECTCM) scanning techniques. MethodsA prospective, single-center study was performed at Prince Sultan Cardiac Centre, Qassim, Saudi Arabia. A total of 104 patients with low-to- intermediate probability of coronary artery disease (CAD) underwent CTA with either PGA or ECTCM acquisition. PGA was performed during the study period and compared with the last 50 CTAs previously done using ECTCM. A 4-point scale was used to assess the image quality subjectively. Objective image quality was assessed using image signal, noise, and signal-to-noise ratio (SNR). ResultsPatient‘s Baseline characteristics were not different between the two scanning protocols. The 4-point score of subjective image quality showed no significant differences between the PGA and ECTCM scans (2.9±0.7, 2.96±0.7, respectively; p=0.87). The objective image quality showed significantly higher noise and lower SNR with PGA compared with ECTCM (31±9, 27±9, respectively; p<0.001 for noise) and (15±5, 17±7, respectively; p<0.001 for SNR), with no statistical difference in the image signal (434±123, 425±103 HU, respectively, p=0.7).Radiation exposure was significantly lower with PGA than with ECTCM. The dose-length product (DLP) for PGA was 334±130mGy, compared with 822±286mGy for the ECTCM. This corresponds to a 59% reduction in radiation exposure (p<0.0001). ConclusionsAlthough prospective ECG-triggered axial scanning increased image noise, it maintained subjective image quality and was associated with a 59% reduction in radiation exposure when compared with ECTCM.

MDCT evaluation of aortic root and aortic valve prior to TAVI. What is the optimal imaging time point in the cardiac cycle?

ObjectivesTo determine the optimal imaging time point for transcatheter aortic valve implantation (TAVI) therapy planning by comprehensive evaluation of the aortic root.MethodsMultidetector-row CT (MDCT) examination with retrospective ECG gating was retrospectively performed in 64 consecutive patients referred for pre-TAVI assessment. Eighteen different parameters of the aortic root were evaluated at 11 different time points in the cardiac cycle. Time points at which maximal (or minimal) sizes were determined, and dimension differences to other time points were evaluated. Theoretical prosthesis sizing based on different measurements was compared.ResultsLargest dimensions were found between 10 and 20 % of the cardiac cycle for annular short diameter (10 %); mean diameter (10 %); effective diameter and circumference-derived diameter (20 %); distance from the annulus to right coronary artery ostium (10 %); aortic root at the left coronary artery level (20 %); aortic root at the widest portion of coronary sinuses (20 %); and right leaflet length (20 %). Prosthesis size selection differed depending on the chosen measurements in 25–75 % of cases.ConclusionSignificant changes in anatomical structures of the aortic root during the cardiac cycle are crucial for TAVI planning. Imaging in systole is mandatory to obtain maximal dimensions.Key Points• Most aortic root structures undergo significant dimensional changes throughout the cardiac cycle. • The largest dimensions of aortic parameters should be determined to optimize TAVI. • Circumference-derived diameter showed maximum dimension at 20 % of the cardiac cycle.

The effect of relaxing music on heart rate and heart rate variability during ECG GATED-myocardial perfusion scintigraphy

BackgroundThe positive changes in human behavior caused by relaxing music demonstrate the psychological effect of music on human body. A meta-analytical study has shown that relaxing music affects blood pressure and heart rate in coronary heart patients and cancer patients. The aim of our study is to research whether there is a significant effect on heart rate and heart rate variability due to listening to relaxing music during ECG GATED MPS imaging under gamma camera. MethodThe music group (n = 50 patients) could choose from 15 different musical types including folk music (no lyric). The other 50 patients were placed in a “no music group” and did not get headphones or any music. ResultsThere was a statistically significant reduction in the heart rate of patients in the music group compared to those in the control group. ConclusionsRelaxing music provides great benefits to both patient and clinician. There is close relationship between relaxing music and health procedure, can use every area of the health noninvasiv, safe, cheap and is a method don't have side effect.

Segmented golden ratio radial reordering for dynamic cardiac MRI with variable temporal resolution

Background Golden angle radial reordering (GA) has been applied in many abdominal and neurological imaging applications to allow for retrospective choice of temporal resolution by providing a near-uniform k-space sampling within any image reconstruction time window [1]. However, its application in cardiac imaging is limited because the ECG-gated acquisition, which is required in most cases, breaks a single reconstruction window into several temporally isolated k-space data so that the k-space coverage may not be as uniform as GA without ECG gating (Fig. 1a) [2]. Therefore, we sought to investigate the image artifacts caused by applying GA to ECG-gated cardiac imaging and propose a segmented GA method to address this issue.