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Sample records for cardiac hybrid imaging

  1. Multi-Echo Segmented k-space Imaging: An Optimized Hybrid Sequence for Ultrafast Cardiac Imaging

    PubMed Central

    Reeder, Scott B.; Atalar, Ergin; Faranesh, Anthony Z.; McVeigh, Elliot R.

    2007-01-01

    Cardiac magnetic resonance imaging requires high temporal resolution to resolve motion and contrast uptake with low total scan times to avoid breathing artifacts. While spoiled gradient echo (SPGR) imaging is robust and reproducible, it is relatively inefficient and requires long breath-holds to acquire high time resolution movies of the heart. Echo planar imaging (EPI) is highly efficient with excellent signal-to-noise ratio (SNR) behavior; however, it is particularly difficult to use in the heart because of its sensitivity to chemical shift, susceptibility, and motion. EPI may also require reference scans, which are used to measure hardware delays and phase offsets that cause ghosting artifacts; these reference scans are more difficult and less reliable in the heart. Consequently, a hybrid EPI/SPGR sequence is proposed for application to rapid cardiac imaging. A detailed optimization of SNR and echo train length for multi-echo sequences is presented. It is shown that significant reductions in total scan time are possible while maintaining good image quality. This will allow complete motion sampling of the entire heart in one to three breath-holds, necessary for MR cardiac dobutamine stress testing. Improved speed performance also permits sampling of three to six slices every heartbeat for bolus injection perfusion studies. PMID:10080287

  2. Cardiac SPECT/CCTA hybrid imaging : One answer to two questions?

    PubMed

    Kaufmann, P A; Buechel, R R

    2016-08-01

    Noninvasive cardiac imaging has witnessed tremendous advances in the recent past, particularly with regard to coronary computed tomography angiography (CCTA) where substantial improvements in image quality have been achieved while at the same time patients' radiation dose exposure has been reduced to the sub-millisievert range. Similarly, for single-photon emission computed tomography (SPECT) the introduction of novel cadmium-zinc-telluride-based semiconductor detectors has significantly improved system sensitivity and image quality, enabling fast image acquisition within less than 2-3 min or reduction of radiation dose exposure to less than 5 mSv. However, neither imaging modality alone is able to fully cover the two aspects of coronary artery disease (CAD), that is, morphology and function. Both modalities have distinct advantages and shortcomings: While CCTA may prove a superb modality for excluding CAD through its excellent negative predictive value, it does not allow for assessment of hemodynamic relevance if obstructive coronary lesions are detected. Conversely, SPECT myocardial perfusion imaging cannot provide any information on the presence or absence of subclinical coronary atherosclerosis. This article aims to highlight the great potential of cardiac hybrid imaging that allows for a comprehensive evaluation of CAD through combination of both morphological and functional information by fusing SPECT with CCTA. PMID:27286848

  3. Imaging of cardiac sarcoidosis.

    PubMed

    Erthal, Fernanda; Juneau, Daniel; Lim, Siok P; Dwivedi, Girish; Nery, Pablo B; Birnie, David; Beanlands, Rob S

    2016-09-01

    Sarcoidosis is a multisystem inflammatory disease. Cardiac involvement is described in up to 50% of the cases. The disease spectrum is wide and cardiac manifestations ranges from being asymptomatic to heart failure, arrhythmias and sudden cardiac death. The diagnosis of cardiac sarcoidosis can be challenging due to its non-specific nature and the focal involvement of the heart. In this review, we discuss the utility of a stepwise approach with multimodality cardiac imaging in the diagnosis and management of CS. PMID:27225318

  4. Comparative cardiac imaging

    SciTech Connect

    Brundage, B.H.

    1990-01-01

    This book is designed to compare all major cardiac imaging techniques. All major imaging techniques - including conventional angiography, digital angiography, echocardiography and Doppler imaging, conventional radioisotope techniques, computed tomography, and magnetic resonance imaging - are covered in this text as they apply to the major cardiovascular disorders. There is brief coverage of positron emission tomography and an extensive presentation of ultrafast computed tomography.

  5. Cardiac imaging in adults

    SciTech Connect

    Jaffe, C.C.

    1987-01-01

    This book approaches adult cardiac disease from the correlative imaging perspective. It includes chest X-rays and angiographs, 2-dimensional echocardiograms with explanatory diagrams for clarity, plus details on digital radiology, nuclear medicine techniques, CT and MRI. It also covers the normal heart, valvular heart disease, myocardial disease, pericardial disease, bacterial endocarditis, aortic aneurysm, cardiac tumors, and congenital heart disease of the adult. It points out those aspects where one imaging technique has significant superiority.

  6. Cardiac action potential imaging

    NASA Astrophysics Data System (ADS)

    Tian, Qinghai; Lipp, Peter; Kaestner, Lars

    2013-06-01

    Action potentials in cardiac myocytes have durations in the order of magnitude of 100 milliseconds. In biomedical investigations the documentation of the occurrence of action potentials is often not sufficient, but a recording of the shape of an action potential allows a functional estimation of several molecular players. Therefore a temporal resolution of around 500 images per second is compulsory. In the past such measurements have been performed with photometric approaches limiting the measurement to one cell at a time. In contrast, imaging allows reading out several cells at a time with additional spatial information. Recent developments in camera technologies allow the acquisition with the required speed and sensitivity. We performed action potential imaging on isolated adult cardiomyocytes of guinea pigs utilizing the fluorescent membrane potential sensor di-8-ANEPPS and latest electron-multiplication CCD as well as scientific CMOS cameras of several manufacturers. Furthermore, we characterized the signal to noise ratio of action potential signals of varying sets of cameras, dye concentrations and objective lenses. We ensured that di-8-ANEPPS itself did not alter action potentials by avoiding concentrations above 5 μM. Based on these results we can conclude that imaging is a reliable method to read out action potentials. Compared to conventional current-clamp experiments, this optical approach allows a much higher throughput and due to its contact free concept leaving the cell to a much higher degree undisturbed. Action potential imaging based on isolated adult cardiomyocytes can be utilized in pharmacological cardiac safety screens bearing numerous advantages over approaches based on heterologous expression of hERG channels in cell lines.

  7. Cardiac Imaging System

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Although not available to all patients with narrowed arteries, balloon angioplasty has expanded dramatically since its introduction with an estimated further growth to 562,000 procedures in the U.S. alone by 1992. Growth has fueled demand for higher quality imaging systems that allow the cardiologist to be more accurate and increase the chances of a successful procedure. A major advance is the Digital Cardiac Imaging (DCI) System designed by Philips Medical Systems International, Best, The Netherlands and marketed in the U.S. by Philips Medical Systems North America Company. The key benefit is significantly improved real-time imaging and the ability to employ image enhancement techniques to bring out added details. Using a cordless control unit, the cardiologist can manipulate images to make immediate assessment, compare live x-ray and roadmap images by placing them side-by-side on monitor screens, or compare pre-procedure and post procedure conditions. The Philips DCI improves the cardiologist's precision by expanding the information available to him.

  8. Cardiac 4D Ultrasound Imaging

    NASA Astrophysics Data System (ADS)

    D'hooge, Jan

    Volumetric cardiac ultrasound imaging has steadily evolved over the last 20 years from an electrocardiography (ECC) gated imaging technique to a true real-time imaging modality. Although the clinical use of echocardiography is still to a large extent based on conventional 2D ultrasound imaging it can be anticipated that the further developments in image quality, data visualization and interaction and image quantification of three-dimensional cardiac ultrasound will gradually make volumetric ultrasound the modality of choice. In this chapter, an overview is given of the technological developments that allow for volumetric imaging of the beating heart by ultrasound.

  9. Dual gated nuclear cardiac images

    SciTech Connect

    Zubal, I.G.; Bennett, G.W.; Bizais, Y.; Brill, A.B.

    1984-02-01

    A data acquisition system has been developed to collect camera events simultaneously with continually digitized electrocardiograph signals and respiratory flow measurements. Software processing of the list mode data creates more precisely gated cardiac frames. Additionally, motion blur due to heart movement during breathing is reduced by selecting events within a specific respiratory phase. Thallium myocardium images of a healthy volunteer show increased definition. This technique of combined cardiac and respiratory gating has the potential of improving the detectability of small lesions, and the characterization of cardiac wall motion.

  10. Cardiac Imaging In Athletes.

    PubMed

    Khan, Asaad A; Safi, Lucy; Wood, Malissa

    2016-01-01

    Athletic heart syndrome refers to the physiological and morphological changes that occur in a human heart after repetitive strenuous physical exercise. Examples of exercise-induced changes in the heart include increases in heart cavity dimensions, augmentation of cardiac output, and increases in heart muscle mass. These cardiac adaptations vary based on the type of exercise performed and are often referred to as sport-specific cardiac remodeling. The hemodynamic effects of endurance and strength training exercise lead to these adaptations. Any abnormalities in chamber dilatation and left ventricular function usually normalize with cessation of exercise. Athletic heart syndrome is rare and should be differentiated from pathologic conditions such as hypertrophic cardiomyopathy, left ventricular noncompaction, and arrhythmogenic right ventricular dysplasia when assessing a patient for athletic heart syndrome. This paper describes specific adaptations that occur in athletic heart syndrome and tools to distinguish between healthy alterations versus underlying pathology. PMID:27486490

  11. Cardiac Imaging In Athletes

    PubMed Central

    Khan, Asaad A.; Safi, Lucy; Wood, Malissa

    2016-01-01

    Athletic heart syndrome refers to the physiological and morphological changes that occur in a human heart after repetitive strenuous physical exercise. Examples of exercise-induced changes in the heart include increases in heart cavity dimensions, augmentation of cardiac output, and increases in heart muscle mass. These cardiac adaptations vary based on the type of exercise performed and are often referred to as sport-specific cardiac remodeling. The hemodynamic effects of endurance and strength training exercise lead to these adaptations. Any abnormalities in chamber dilatation and left ventricular function usually normalize with cessation of exercise. Athletic heart syndrome is rare and should be differentiated from pathologic conditions such as hypertrophic cardiomyopathy, left ventricular noncompaction, and arrhythmogenic right ventricular dysplasia when assessing a patient for athletic heart syndrome. This paper describes specific adaptations that occur in athletic heart syndrome and tools to distinguish between healthy alterations versus underlying pathology. PMID:27486490

  12. MR imaging of cardiac tumors.

    PubMed

    Sparrow, Patrick J; Kurian, John B; Jones, Tim R; Sivananthan, Mohan U

    2005-01-01

    Magnetic resonance (MR) imaging is an important tool in the evaluation of cardiac neoplasms. T1-weighted, T2-weighted, and gadolinium-enhanced sequences are used for anatomic definition and tissue characterization, whereas cine gradient-echo imaging is used to assess functional effects. Recent improvements in pulse sequences for cardiac MR imaging have led to superior image quality, with reduced motion artifact and improved signal-to-noise ratio and tissue contrast. Although there is some overlap in the MR imaging appearances of cardiac tumors, particularly of primary malignancies, differences in characteristic locations and features should allow confident differentiation between benign and malignant tumors. Indicators of malignancy at MR imaging are invasive behavior, involvement of the right side of the heart or the pericardium, tissue inhomogeneity, diameter greater than 5 cm, and enhancement after administration of gadolinium contrast material (as a result of higher tissue vascularity). Concomitant pericardial or pleural effusions are rare in benign processes but occur in about 50% of cases of malignant tumors. MR imaging offers improved resolution, a larger field of view, and superior soft-tissue contrast compared with those of echocardiography, suggesting that knowledge of the MR imaging features of cardiac neoplasms is important for accurate diagnosis and management. PMID:16160110

  13. Evaluation of a real-time hybrid three-dimensional echo and X-ray imaging system for guidance of cardiac catheterisation procedures.

    PubMed

    Housden, R J; Arujuna, A; Ma, Y; Nijhof, N; Gijsbers, G; Bullens, R; O'Neill, M; Cooklin, M; Rinaldi, C A; Gill, J; Kapetanakis, S; Hancock, J; Thomas, M; Razavi, R; Rhode, K S

    2012-01-01

    Minimally invasive cardiac surgery is made possible by image guidance technology. X-ray fluoroscopy provides high contrast images of catheters and devices, whereas 3D ultrasound is better for visualising cardiac anatomy. We present a system in which the two modalities are combined, with a trans-esophageal echo volume registered to and overlaid on an X-ray projection image in real-time. We evaluate the accuracy of the system in terms of both temporal synchronisation errors and overlay registration errors. The temporal synchronisation error was found to be 10% of the typical cardiac cycle length. In 11 clinical data sets, we found an average alignment error of 2.9 mm. We conclude that the accuracy result is very encouraging and sufficient for guiding many types of cardiac interventions. The combined information is clinically useful for placing the echo image in a familiar coordinate system and for more easily identifying catheters in the echo volume.

  14. Cardiac arrest during dipyridamole imaging

    SciTech Connect

    Blumenthal, M.S.; McCauley, C.S.

    1988-05-01

    A case of cardiac arrest and subsequent acute myocardial infarction occurring during thallium-201 imaging with oral dipyridamole augmentation is presented. Previous reports emphasizing the safety of this procedure are briefly reviewed and a recommendation for close hemodynamic and arrhythmia monitoring during the study is made. Large doses of oral dipyridamole may be contraindicated in patients with unstable angina.

  15. Cardiac imaging: does radiation matter?

    PubMed Central

    Einstein, Andrew J.; Knuuti, Juhani

    2012-01-01

    The use of ionizing radiation in cardiovascular imaging has generated considerable discussion. Radiation should not be considered in isolation, but rather in the context of a careful examination of the benefits, risks, and costs of cardiovascular imaging. Such consideration requires an understanding of some fundamental aspects of the biology, physics, epidemiology, and terminology germane to radiation, as well as principles of radiological protection. This paper offers a concise, contemporary perspective on these areas by addressing pertinent questions relating to radiation and its application to cardiac imaging. PMID:21828062

  16. Quantifying the Area-at-Risk in Reperfused STEMI Patients Using Hybrid Cardiac PET-MR Imaging

    PubMed Central

    Bulluck, Heerajnarain; White, Steven K.; Fröhlich, Georg M.; Casson, Steven G.; O’Meara, Celia; Newton, Ayla; Nicholas, Jennifer; Weale, Peter; Wan, Simon M.Y.; Sirker, Alex; Moon, James C.; Yellon, Derek M.; Groves, Ashley; Menezes, Leon; Hausenloy, Derek J

    2016-01-01

    Background Hybrid Positron Emission Tomography and Magnetic Resonance (PET-MR) allows the advantages of MR in tissue characterizing the myocardium to be combined with the unique metabolic insights of PET. We hypothesized that the area of reduced myocardial glucose uptake would closely match the area-at-risk (AAR) delineated by T2-mapping in ST-segment elevation myocardial infarction (STEMI) patients. Methods and Results Hybrid PET-MR using 18F-fluorodeoxyglucose (FDG) for glucose uptake was performed in 21 STEMI patients at a median of 5 days. Follow-up scans were performed in a subset of patients 12 months later. The area of reduced FDG uptake was significantly larger than the infarct size quantified by late gadolinium enhancement (LGE) (37.2±11.6% versus 22.3±11.7%; P<0.001), and closely matched the AAR by T2-mapping (37.2±11.6% versus 36.3±12.2%; P=0.10, R 0.98, bias 0.9±4.4%). On the follow-up scans, the area of reduced FDG uptake was significantly smaller in size when compared to the acute scans (19.5 [6.3-31.8]% versus 44.0 [21.3-55.3]%, P=0.002), and closely correlated with the areas of LGE (R 0.98) with a small bias of 2.0±5.6%. An FDG uptake of ≥45% on the acute scans could predict viable myocardium on the follow-up scan. Both transmural extent of LGE and FDG uptake on the acute scan performed equally well to predict segmental wall motion recovery. Conclusions Hybrid PET-MR in the reperfused STEMI patient showed reduced myocardial glucose uptake within the AAR and closely matched the AAR delineated by T2-mapping. FDG uptake, as well as transmural extent of LGE acutely can identify viable myocardial segments. PMID:26926269

  17. Real time cardiac radionuclide imaging

    SciTech Connect

    Jarkewicz, G.G.

    1986-04-29

    A data acquisition system is described for use in radionuclide cardiac imaging of a patient having been administered a myocardium specific radionuclide, comprising: (a) means for monitoring the electrical activity of the heart; (b) first temporary storage means for accumulating respective pages of data corresponding to nuclear events during each cardiac cycle; (c) means, responsive to the means for monitoring, for determining the time duration of each successive cardiac cycle; (d) means for comparing each determined duration of a cardiac cycle with a preselected time duration range; (e) second temporary storage means; and (f) means for conditionally transferring pages of data from the first temporary storage means to the second temporary storage means if the measured duration associated with each page has predetermined correspondence with the preselected duration range, whereby pages of data having the predetermined correspondence may be collated into a quasi-real time study, while pages of data having different correspondence with the preselected time duration range are discarded from the study.

  18. Ultrasound Imaging in Teaching Cardiac Physiology

    ERIC Educational Resources Information Center

    Johnson, Christopher D.; Montgomery, Laura E. A.; Quinn, Joe G.; Roe, Sean M.; Stewart, Michael T.; Tansey, Etain A.

    2016-01-01

    This laboratory session provides hands-on experience for students to visualize the beating human heart with ultrasound imaging. Simple views are obtained from which students can directly measure important cardiac dimensions in systole and diastole. This allows students to derive, from first principles, important measures of cardiac function, such…

  19. Hybrid Diffusion Imaging

    PubMed Central

    Wu, Yu-Chien; Alexander, Andrew L.

    2007-01-01

    Diffusion measurements in the human central nervous system are complex to characterize and a broad spectrum of methods have been proposed. In this study, a comprehensive diffusion encoding and analysis approach, Hybrid Diffusion Imaging (HYDI), is described. The HYDI encoding scheme is composed of multiple concentric “shells” of constant diffusion-weighting, which may be used to characterize the signal behavior with low, moderate and high diffusion-weighting. HYDI facilitates the application of multiple data-analyses strategies including diffusion tensor imaging (DTI), multi-exponential diffusion measurements, diffusion spectrum imaging (DSI) and q-ball imaging (QBI). These different analysis strategies may provide complementary information. DTI measures (mean diffusivity and fractional anisotropy) may be estimated from either data in the inner shells or the entire HYDI data. Fast and slow diffusivities were estimated using a nonlinear least-squares bi-exponential fit on geometric means of the HYDI shells. DSI measurements from the entire HYDI data yield empirical model-independent diffusion information and are well-suited for characterizing tissue regions with complex diffusion behavior. DSI measurements were characterized using the zero displacement probability and the mean squared displacement. The outermost HYDI shell was analyzed using QBI analysis to estimate the orientation distribution function (ODF), which is useful for characterizing the directions of multiple fiber groups within a voxel. In this study, a HYDI encoding scheme with 102 diffusion-weighted measurements was obtained over most of the human cerebrum in under 30 minutes. PMID:17481920

  20. Cardiac nuclear imaging - Principles, instrumentation and pitfalls

    SciTech Connect

    Strauss, H.W.; Mckusick, K.A.; Bingham, J.B.

    1980-12-18

    Nuclear methods of cardiac imaging require a radiolabeled tracer, a collimator to assure interaction of photons from specific areas of the heart with the imaging device, equipment which converts gamma photon energy into an electrical signal which can be displayed, and a computer to record and quantify the data. Nuclear imaging is based on the averaging of many cardiac cycles, while nuclear probes supply information which can be analyzed only on a beat-by-beat basis imaging data can be reviewed visually and quantitatively. It is concluded that nuclear cardiac imaging can detect abnormal functions at rest or after interventions, and can be used both for outpatients and acutely ill persons in intensive care units.

  1. Gold nanoparticle-decellularized matrix hybrids for cardiac tissue engineering.

    PubMed

    Shevach, Michal; Fleischer, Sharon; Shapira, Assaf; Dvir, Tal

    2014-10-01

    Decellularized matrices are valuable scaffolds for engineering functional cardiac patches for treating myocardial infarction. However, the lack of quick and efficient electrical coupling between adjacent cells may jeopardize the success of the treatment. To address this issue, we have deposited gold nanoparticles on fibrous decellularized omental matrices and investigated their morphology, conductivity, and degradation. We have shown that cardiac cells engineered within the hybrid scaffolds exhibited elongated and aligned morphology, massive striation, and organized connexin 43 electrical coupling proteins. Finally, we have shown that the hybrid patches demonstrated superior function as compared to pristine patches, including a stronger contraction force, lower excitation threshold, and faster calcium transients.

  2. Hybrid 3D printing: a game-changer in personalized cardiac medicine?

    PubMed

    Kurup, Harikrishnan K N; Samuel, Bennett P; Vettukattil, Joseph J

    2015-12-01

    Three-dimensional (3D) printing in congenital heart disease has the potential to increase procedural efficiency and patient safety by improving interventional and surgical planning and reducing radiation exposure. Cardiac magnetic resonance imaging and computed tomography are usually the source datasets to derive 3D printing. More recently, 3D echocardiography has been demonstrated to derive 3D-printed models. The integration of multiple imaging modalities for hybrid 3D printing has also been shown to create accurate printed heart models, which may prove to be beneficial for interventional cardiologists, cardiothoracic surgeons, and as an educational tool. Further advancements in the integration of different imaging modalities into a single platform for hybrid 3D printing and virtual 3D models will drive the future of personalized cardiac medicine.

  3. Hybrid 3D printing: a game-changer in personalized cardiac medicine?

    PubMed

    Kurup, Harikrishnan K N; Samuel, Bennett P; Vettukattil, Joseph J

    2015-12-01

    Three-dimensional (3D) printing in congenital heart disease has the potential to increase procedural efficiency and patient safety by improving interventional and surgical planning and reducing radiation exposure. Cardiac magnetic resonance imaging and computed tomography are usually the source datasets to derive 3D printing. More recently, 3D echocardiography has been demonstrated to derive 3D-printed models. The integration of multiple imaging modalities for hybrid 3D printing has also been shown to create accurate printed heart models, which may prove to be beneficial for interventional cardiologists, cardiothoracic surgeons, and as an educational tool. Further advancements in the integration of different imaging modalities into a single platform for hybrid 3D printing and virtual 3D models will drive the future of personalized cardiac medicine. PMID:26465262

  4. Emergency cardiac imaging: state of the art.

    PubMed

    Kuo, Dick; Dilsizian, Vasken; Prasad, Rajnish; White, Charles S

    2006-02-01

    Multiple strategies and testing modalities are available to evaluate patients presenting to the emergency department with cardiac complaints. Many provide anatomic and prognostic information about coronary stenosis and long-term out-comes. Although nuclear and stress echo imaging have the ability to predict outcomes in patients in the emergency department population, the newer modalities of cardiac imaging (EBCT, MDCT,and CMR) continue to show promising results and may soon be incorporated into emergency department chest pain centers. Protocols can be developed within an institution to meet the needs of the patient population while minimizing risk and improving outcomes for all patients. PMID:16326256

  5. Cardiac imaging using gated magnetic resonance

    SciTech Connect

    Lanzer, P.; Botvinick, E.H.; Schiller, N.B.

    1984-01-01

    To overcome the limitations of magnetic resonance (MR) cardiac imaging using nongated data acquisition, three methods for acquiring a gating signal, which could be applied in the presence of a magnetic field, were tested; an air-filled plethysmograph, a laser-Doppler capillary perfusion flowmeter, and an electrocardiographic gating device. The gating signal was used for timing of MR imaging sequences (IS). Application of each gating method yielded significant improvements in structural MR image resolution of the beating heart, although with both plethysmography and laser-Doppler velocimetry it was difficult to obtain cardiac images from the early portion of the cardiac cycle due to an intrinsic delay between the ECG R wave and peripheral detection of the gating signal. Variations in the temporal relationship between the R wave and plethysmographic and laser-Doppler signals produced inconsistencies in the timing of IS. Since the ECG signal is virtually free of these problems, the preferable gating technique is IS synchronization with an electrocardiogram. The gated images acquired with this method provide sharp definition of internal cardiac morphology and can be temporarily referenced to end diastole and end systole or intermediate points.

  6. Cardiac-state-driven CT image reconstruction algorithm for cardiac imaging

    NASA Astrophysics Data System (ADS)

    Cesmeli, Erdogan; Edic, Peter M.; Iatrou, Maria; Hsieh, Jiang; Gupta, Rajiv; Pfoh, Armin H.

    2002-05-01

    Multi-slice CT scanners use EKG gating to predict the cardiac phase during slice reconstruction from projection data. Cardiac phase is generally defined with respect to the RR interval. The implicit assumption made is that the duration of events in a RR interval scales linearly when the heart rate changes. Using a more detailed EKG analysis, we evaluate the impact of relaxing this assumption on image quality. We developed a reconstruction algorithm that analyzes the associated EKG waveform to extract the natural cardiac states. A wavelet transform was used to decompose each RR-interval into P, QRS, and T waves. Subsequently, cardiac phase was defined with respect to these waves instead of a percentage or time delay from the beginning or the end of RR intervals. The projection data was then tagged with the cardiac phase and processed using temporal weights that are function of their cardiac phases. Finally, the tagged projection data were combined from multiple cardiac cycles using a multi-sector algorithm to reconstruct images. The new algorithm was applied to clinical data, collected on a 4-slice (GE LightSpeed Qx/i) and 8-slice CT scanner (GE LightSpeed Plus), with heart rates of 40 to 80 bpm. The quality of reconstruction is assessed by the visualization of the major arteries, e.g. RCA, LAD, LC in the reformat 3D images. Preliminary results indicate that Cardiac State Driven reconstruction algorithm offers better image quality than their RR-based counterparts.

  7. Imaging techniques in cardiac resynchronization therapy

    PubMed Central

    Sá, Maria Isabel; de Roos, Albert; Westenberg, Jos J. M.

    2007-01-01

    Cardiac resynchronization therapy is a high cost therapeutic option with proven efficacy on improving symptoms of ventricular failure and for reducing both hospitalization and mortality. However, a significant number of patients do not respond to cardiac resynchronization therapy that is due to various reasons. Identification of the optimal pacing site is crucial to obtain the best therapeutic result that necessitates careful patient selection. Currently, using echocardiography for mechanical dyssynchrony assessment performs patient selection. Multi-Detector-Row Computed Tomography (MDCT) and Magnetic Resonance Imaging (MRI) are new imaging techniques that may assist the cardiologist in patient selection. These new imaging techniques have the potential to improve the success rate of cardiac resynchronization therapy, due to pre-interventional evaluation of the venous coronary anatomy, to evaluation of the presence of scar tissue, and to improved evaluation of mechanical dyssynchrony. In conclusion, clinical issues associated with heart failure in potential candidates for cardiac resynchronization therapy, and the information regarding this therapy that can be provided by the imaging techniques echocardiography, MDCT, and MRI, are reviewed. PMID:17503216

  8. Ultrasound imaging in teaching cardiac physiology.

    PubMed

    Johnson, Christopher D; Montgomery, Laura E A; Quinn, Joe G; Roe, Sean M; Stewart, Michael T; Tansey, Etain A

    2016-09-01

    This laboratory session provides hands-on experience for students to visualize the beating human heart with ultrasound imaging. Simple views are obtained from which students can directly measure important cardiac dimensions in systole and diastole. This allows students to derive, from first principles, important measures of cardiac function, such as stroke volume, ejection fraction, and cardiac output. By repeating the measurements from a subject after a brief exercise period, an increase in stroke volume and ejection fraction are easily demonstrable, potentially with or without an increase in left ventricular end-diastolic volume (which indicates preload). Thus, factors that affect cardiac performance can readily be discussed. This activity may be performed as a practical demonstration and visualized using an overhead projector or networked computers, concentrating on using the ultrasound images to teach basic physiological principles. This has proved to be highly popular with students, who reported a significant improvement in their understanding of Frank-Starling's law of the heart with ultrasound imaging. PMID:27445285

  9. Simulating cardiac ultrasound image based on MR diffusion tensor imaging

    PubMed Central

    Qin, Xulei; Wang, Silun; Shen, Ming; Lu, Guolan; Zhang, Xiaodong; Wagner, Mary B.; Fei, Baowei

    2015-01-01

    Purpose: Cardiac ultrasound simulation can have important applications in the design of ultrasound systems, understanding the interaction effect between ultrasound and tissue and setting the ground truth for validating quantification methods. Current ultrasound simulation methods fail to simulate the myocardial intensity anisotropies. New simulation methods are needed in order to simulate realistic ultrasound images of the heart. Methods: The proposed cardiac ultrasound image simulation method is based on diffusion tensor imaging (DTI) data of the heart. The method utilizes both the cardiac geometry and the fiber orientation information to simulate the anisotropic intensities in B-mode ultrasound images. Before the simulation procedure, the geometry and fiber orientations of the heart are obtained from high-resolution structural MRI and DTI data, respectively. The simulation includes two important steps. First, the backscatter coefficients of the point scatterers inside the myocardium are processed according to the fiber orientations using an anisotropic model. Second, the cardiac ultrasound images are simulated with anisotropic myocardial intensities. The proposed method was also compared with two other nonanisotropic intensity methods using 50 B-mode ultrasound image volumes of five different rat hearts. The simulated images were also compared with the ultrasound images of a diseased rat heart in vivo. A new segmental evaluation method is proposed to validate the simulation results. The average relative errors (AREs) of five parameters, i.e., mean intensity, Rayleigh distribution parameter σ, and first, second, and third quartiles, were utilized as the evaluation metrics. The simulated images were quantitatively compared with real ultrasound images in both ex vivo and in vivo experiments. Results: The proposed ultrasound image simulation method can realistically simulate cardiac ultrasound images of the heart using high-resolution MR-DTI data. The AREs of their

  10. Cardiac imaging in valvular heart disease

    PubMed Central

    Choo, W S; Steeds, R P

    2011-01-01

    The aim of this article is to provide a perspective on the relative importance and contribution of different imaging modalities in patients with valvular heart disease. Valvular heart disease is increasing in prevalence across Europe, at a time when the clinical ability of physicians to diagnose and assess severity is declining. Increasing reliance is placed on echocardiography, which is the mainstay of cardiac imaging in valvular heart disease. This article outlines the techniques used in this context and their limitations, identifying areas in which dynamic imaging with cardiovascular magnetic resonance and multislice CT are expanding. PMID:22723532

  11. Cardiac phase detection in intravascular ultrasound images

    NASA Astrophysics Data System (ADS)

    Matsumoto, Monica M. S.; Lemos, Pedro Alves; Yoneyama, Takashi; Furuie, Sergio Shiguemi

    2008-03-01

    Image gating is related to image modalities that involve quasi-periodic moving organs. Therefore, during intravascular ultrasound (IVUS) examination, there is cardiac movement interference. In this paper, we aim to obtain IVUS gated images based on the images themselves. This would allow the reconstruction of 3D coronaries with temporal accuracy for any cardiac phase, which is an advantage over the ECG-gated acquisition that shows a single one. It is also important for retrospective studies, as in existing IVUS databases there are no additional reference signals (ECG). From the images, we calculated signals based on average intensity (AI), and, from consecutive frames, average intensity difference (AID), cross-correlation coefficient (CC) and mutual information (MI). The process includes a wavelet-based filter step and ascendant zero-cross detection in order to obtain the phase information. Firstly, we tested 90 simulated sequences with 1025 frames each. Our method was able to achieve more than 95.0% of true positives and less than 2.3% of false positives ratio, for all signals. Afterwards, we tested in a real examination, with 897 frames and ECG as gold-standard. We achieved 97.4% of true positives (CC and MI), and 2.5% of false positives. For future works, methodology should be tested in wider range of IVUS examinations.

  12. Cardiac image segmentation using spatiotemporal clustering

    NASA Astrophysics Data System (ADS)

    Galic, Sasa; Loncaric, Sven

    2001-07-01

    Image segmentation is an important and challenging problem in image analysis. Segmentation of moving objects in image sequences is even more difficult and computationally expensive. In this work we propose a technique for spatio- temporal segmentation of medical sequences based on K-mean clustering in the feature vector space. The motivation for spatio-temporalsegmentation approach comes from the fact that motion is a useful clue for object segmentation. Two- dimensional feature vector has been used for clustering in the feature space. In this paper we apply the proposed technique to segmentation of cardiac images. The first feature used in this particular application is image brightness, which reveals the structure of interest in the image. The second feature is the Euclidean norm of the optical flow vector. The third feature is the three- dimensional optical flow vector, which consists of computed motion in all three dimensions. The optical flow itself is computed using Horn-Schunck algorithm. The fourth feature is the mean brightness of the input image in a local neighborhood. By applying the clustering algorithm it is possible to detect moving object in the image sequence. The experiment has been conducted using a sequence of ECG-gated magnetic resonance (MR) images of a beating heart taken as in time so in the space.

  13. Image based physiological monitoring of cardiac function

    NASA Astrophysics Data System (ADS)

    Maier, Corinna S.; Bock, Michael; Semmler, Wolfhard; Lorenz, Christine H.

    2008-03-01

    A new framework for image based physiological cardiac monitoring is proposed based on repeated imaging of critical slice locations in an interventional MRI environment. The aim of this work is to provide a method of detecting pathological changes in the left ventricular (LV) myocardial wall motion where the standard ECG methods are not possible due to distortions by the magnetic field. First MRI LV short axis images are acquired for different phases of the cardiac cycle over RR intervals. Then LV contours are detected based on an established segmentation algorithm. The contour's Fourier Descriptors are calculated to classify myocardial wall into two classes: contracted or not contracted. The classifier is trained during an initial observation period before a pathological change might occur during an intervention. A contour rejected by the classifier using the unconditional, predictive probability of the contour's observation vector as confidence measure is interpreted as a probably pathologic change in the LV myocardial wall motion. To evaluate the performance of the classifier a simple model is introduced for simulating the contours of a pathological, ischemic, LV myocardial wall. The overall performance of the classifier on 516 samples based on healthy volunteer images and 3096 simulated ischemic samples yielded a mean classification error for supervised training of 5.7% and for unsupervised training of 8.7%.

  14. Hybrid Infrared Imager

    NASA Technical Reports Server (NTRS)

    Bailey, Gary C.

    1989-01-01

    Experimental device has low noise and high uniformity. Infrared imaging device combines array of InSb photodetectors with array of silicon field-effect-transistor switches. InSb chip forms roof over Si chip, each InSb detector cell engaging indium bump on corresponding Si switch cell below it. FET switches in 128-by-128 array turn on in sequence, read out charges on 128-by-128 array of photodetectors and multiplex them in serial output that represents pattern of light on array of photodetectors. Useful in sensitive infrared cameras for astronomy, medicine, inspection, and military surveillance. Reads out image data at rates up to 10 MHz and expands to 256-by-256 array.

  15. Cardiac MR imaging: current status and future direction

    PubMed Central

    Van, Tu Anh; Krug, Roland; Hetts, Steven W.; Wilson, Mark W.

    2015-01-01

    Coronary artery disease is currently a worldwide epidemic with increasing impact on healthcare systems. Magnetic resonance imaging (MRI) sequences give complementary information on LV function, regional perfusion, angiogenesis, myocardial viability and orientations of myocytes. T2-weighted short-tau inversion recovery (T2-STIR), fat suppression and black blood sequences have been frequently used for detecting edematous area at risk (AAR) of infarction. T2 mapping, however, indicated that the edematous reaction in acute myocardial infarct (AMI) is not stable and warranted the use of edematous area in evaluating therapies. On the other hand, cine MRI demonstrated reproducible data on LV function in healthy volunteers and LV remodeling in patients. Noninvasive first pass perfusion, using exogenous tracer (gadolinium-based contrast media) and arterial spin labeling MRI, using endogenous tracer (water), are sensitive and useful techniques for evaluating myocardial perfusion and angiogenesis. Recently, new strategies have been developed to quantify myocardial viability using T1-mapping and equilibrium contrast enhanced MR techniques because existing delayed contrast enhancement MRI (DE-MRI) sequences are limited in detecting patchy microinfarct and diffuse fibrosis. These new techniques were successfully used for characterizing diffuse myocardial fibrosis associated with myocarditis, amyloidosis, sarcoidosis heart failure, aortic hypertrophic cardiomyopathy, congenital heart disease, restrictive cardiomyopathy, arrhythmogenic right ventricular dysplasia and hypertension). Diffusion MRI provides information regarding microscopic tissue structure, while diffusion tensor imaging (DTI) helps to characterize the myocardium and monitor the process of LV remodeling after AMI. Novel trends in hybrid imaging, such as cardiac positron emission tomography (PET)/MRI and optical imaging/MRI, are recently under intensive investigation. With the promise of higher spatial

  16. First-Generation Hybrid Compact Compton Imager

    SciTech Connect

    Cunningham, M; Burks, M; Chivers, D; Cork, C; Fabris, L; Gunter, D; Krings, T; Lange, D; Hull, E; Mihailescu, L; Nelson, K; Niedermayr, T; Protic, D; Valentine, J; Vetter, K; Wright, D

    2005-11-07

    At Lawrence Livermore National Laboratory, we are pursuing the development of a gamma-ray imaging system using the Compton effect. We have built our first generation hybrid Compton imaging system, and we have conducted initial calibration and image measurements using this system. In this paper, we present the details of the hybrid Compton imaging system and initial calibration and image measurements.

  17. Transthoracic Cardiac Acoustic Radiation Force Impulse Imaging

    NASA Astrophysics Data System (ADS)

    Bradway, David Pierson

    This dissertation investigates the feasibility of a real-time transthoracic Acoustic Radiation Force Impulse (ARFI) imaging system to measure myocardial function non-invasively in clinical setting. Heart failure is an important cardiovascular disease and contributes to the leading cause of death for developed countries. Patients exhibiting heart failure with a low left ventricular ejection fraction (LVEF) can often be identified by clinicians, but patients with preserved LVEF might be undetected if they do not exhibit other signs and symptoms of heart failure. These cases motivate development of transthoracic ARFI imaging to aid the early diagnosis of the structural and functional heart abnormalities leading to heart failure. M-Mode ARFI imaging utilizes ultrasonic radiation force to displace tissue several micrometers in the direction of wave propagation. Conventional ultrasound tracks the response of the tissue to the force. This measurement is repeated rapidly at a location through the cardiac cycle, measuring timing and relative changes in myocardial stiffness. ARFI imaging was previously shown capable of measuring myocardial properties and function via invasive open-chest and intracardiac approaches. The prototype imaging system described in this dissertation is capable of rapid acquisition, processing, and display of ARFI images and shear wave elasticity imaging (SWEI) movies. Also presented is a rigorous safety analysis, including finite element method (FEM) simulations of tissue heating, hydrophone intensity and mechanical index (MI) measurements, and thermocouple transducer face heating measurements. For the pulse sequences used in later animal and clinical studies, results from the safety analysis indicates that transthoracic ARFI imaging can be safely applied at rates and levels realizable on the prototype ARFI imaging system. Preliminary data are presented from in vivo trials studying changes in myocardial stiffness occurring under normal and abnormal

  18. Cardiac Imaging Techniques for Physicians: Late Enhancement

    PubMed Central

    Kellman, Peter; Arai, Andrew E.

    2012-01-01

    Late enhancement imaging is used to diagnose and characterize a wide range of ischemic and non-ischemic cardiomyopathies, and its use has become ubiquitous in the cardiac MR exam. As the use of late enhancement imaging has matured and the span of applications has widened, the demands on image quality have grown. The characterization of sub-endocardial MI now includes the accurate quantification of scar size, shape, and characterization of borders which have been shown to have prognostic significance. More diverse patterns of late enhancement including patchy, mid-wall, sub-epicardial, or diffuse enhancement are of interest in diagnosing non-ischemic cardiomyopathies. As clinicians are examining late enhancement images for more subtle indication of fibrosis, the demand for lower artifacts has increased. A range of new techniques have emerged to improve the speed and quality of late enhancement imaging including: methods for acquisition during free breathing, and fat water separated imaging for characterizing fibro-fatty infiltration and reduction of artifacts related to the presence of fat. Methods for quantification of T1 and extracellular volume fraction are emerging to tackle the issue of discriminating globally diffuse fibrosis from normal healthy tissue which is challenging using conventional late enhancement methods. The aim of this review will be to describe the current state of the art and to provide a guide to various clinical protocols that are commonly used. PMID:22903654

  19. [Cardiac magnetic resonance imaging and cardiac computed tomography in clinical practice].

    PubMed

    Barone-Rochette, G; Jankowski, A; Rodiere, M

    2014-11-01

    Technological advances have enabled the rapid development of cardiovascular imaging techniques. Cardiac computed tomography (CT) and cardiac magnetic resonance imaging (MRI) have become diagnostic and prognostic tools for the management of patients in routine clinical practice. This review gives the main indications and describes the performance of both techniques.

  20. Ultrasound image guidance of cardiac interventions

    NASA Astrophysics Data System (ADS)

    Peters, Terry M.; Pace, Danielle F.; Lang, Pencilla; Guiraudon, Gérard M.; Jones, Douglas L.; Linte, Cristian A.

    2011-03-01

    Surgical procedures often have the unfortunate side-effect of causing the patient significant trauma while accessing the target site. Indeed, in some cases the trauma inflicted on the patient during access to the target greatly exceeds that caused by performing the therapy. Heart disease has traditionally been treated surgically using open chest techniques with the patient being placed "on pump" - i.e. their circulation being maintained by a cardio-pulmonary bypass or "heart-lung" machine. Recently, techniques have been developed for performing minimally invasive interventions on the heart, obviating the formerly invasive procedures. These new approaches rely on pre-operative images, combined with real-time images acquired during the procedure. Our approach is to register intra-operative images to the patient, and use a navigation system that combines intra-operative ultrasound with virtual models of instrumentation that has been introduced into the chamber through the heart wall. This paper illustrates the problems associated with traditional ultrasound guidance, and reviews the state of the art in real-time 3D cardiac ultrasound technology. In addition, it discusses the implementation of an image-guided intervention platform that integrates real-time ultrasound with a virtual reality environment, bringing together the pre-operative anatomy derived from MRI or CT, representations of tracked instrumentation inside the heart chamber, and the intra-operatively acquired ultrasound images.

  1. Magnetic resonance imaging in cardiac amyloidosis

    SciTech Connect

    O'Donnell, J.K.; Go, R.T.; Bott-Silverman, C.; Feiglin, D.H.; Salcedo, E.; MacIntyre, W.J.

    1984-01-01

    Primary amyloidosis (AL) involves the myocardium in 90% of cases and may present as apparent ischemia, vascular disease, or congestive heart failure. Two-dimensional echocardiography (echo) has proven useful in the diagnosis, particularly in differentiating AL from constrictive pericarditis. The findings of thickened RV and LV myocardium, normal LV cavity dimension, and a diffuse hyperrefractile ''granular sparkling'' appearance are virtually diagnostic. Magnetic resonance (MR) imaging may improve the resolution of anatomic changes seen in cardiac AL and has the potential to provide more specific information based on biochemical tissue alterations. In this preliminary study, the authors obtained both MR and echo images in six patients with AL and biopsy-proven myocardial involvement. 5/6 patients also had Tc-99 PYP myocardial studies including emission tomography (SPECT). MR studies utilized a 0.6 Tesla superconductive magnet. End diastolic gated images were obtained with TE=30msec and TR=R-R interval on the ECG. 6/6 pts. showed LV wall thickening which was concentric and included the septum. Papillary muscles were identified in all and were enlarged in 3/6. 4/6 pts. showed RV wall thickening but to a lesser degree than LV. Pericardial effusions were present in 4 cases. These findings correlated well with the results of echo although MR gave better RV free wall resolution. PYP scans were positive in 3 pts. but there was no correlation with degree of LV thickening. The authors conclude that there are no identifiable MR findings in patients with cardiac AL which encourage further attempts to characterize myocardial involvement by measurement of MR relaxation times in vivo.

  2. Biophotonic Modelling of Cardiac Optical Imaging.

    PubMed

    Bishop, Martin J; Plank, Gernot

    2015-01-01

    Computational models have been recently applied to simulate and better understand the nature of fluorescent photon scattering and optical signal distortion during cardiac optical imaging. The goal of such models is both to provide a useful post-processing tool to facilitate a more accurate and faithful comparison between computational simulations of electrical activity and experiments, as well as providing essential insight into the mechanisms underlying this distortion, suggesting ways in which it may be controlled or indeed utilised to maximise the information derived from the recorded fluorescent signal. Here, we present different modelling methodologies developed and used in the field to simulate both the explicit processes involved in optical signal synthesis and the resulting consequences of the effects of photon scattering within the myocardium upon the optically-detected signal. We focus our attentions to two main types of modelling approaches used to simulate light transport in cardiac tissue, specifically continuous (reaction-diffusion) and discrete stochastic (Monte Carlo) methods. For each method, we provide both a summary of the necessary methodological details of such models, in addition to brief reviews of relevant application studies which have sought to apply these methods to elucidate important information regarding experimentally-recorded optical signals under different circumstances.

  3. Advances in imaging for diagnosis and management of cardiac sarcoidosis.

    PubMed

    Aggarwal, Niti R; Snipelisky, David; Young, Phillip M; Gersh, Bernard J; Cooper, Leslie T; Chareonthaitawee, Panithaya

    2015-09-01

    Sarcoidosis is a multisystem granulomatous disorder with a high prevalence of cardiac involvement. Cardiac sarcoidosis (CS) may be life threatening due to end-stage cardiomyopathy and sudden cardiac death. The frequent absence of specific symptoms and lack of a diagnostic 'gold standard' pose challenges in the diagnosis of CS. Endomyocardial biopsy, although specific, has an unacceptably low sensitivity. Non-invasive cardiac imaging has a huge role in the assessment of patients with known or suspected CS. This comprehensive review compares the diagnostic accuracy, along with advantages and disadvantages, of established and emerging imaging modalities for CS.

  4. Cardiac BMIPP imaging in acute myocardial infarction.

    PubMed

    Nakata, T; Hashimoto, A; Eguchi, M

    1999-02-01

    Fatty acid metabolism functions as a major energy-producing system under aerobic conditions, but it is impaired immediately after myocardial ischaemia. This imaging can provide intracellular information which cannot be obtained by angiographical, perfusional or functional analysis. 123I-BMIPP and perfusion imagings in patients with acute myocardial infarction have demonstrated three different correlations between myocardial perfusion and fatty acid metabolism: concordant defects of perfusion and BMIPP which represent scar or non-viable tissue; lower BMIPP uptake relative to perfusion (perfusion-BMIPP mismatch) which implicates metabolically damaged, often dysynergic, but viable myocardium; and equivalently normal uptakes of perfusion and BMIPP in completely salvaged myocardium. Identification of these perfusion-metabolism correlations contributes to the detection of ischaemia-related myocardial injury in viable and non-viable myocardium, to the prediction of post-ischaemic or post-interventional functional recovery and to the identification of patients who have myocardium at ischaemic risk. Further clinical investigations might reveal more clearly the pathophysiological and prognostic implications of cardiac BMIPP imaging in patients with acute myocardial infarction.

  5. Cardiac Physiology for Radiologists: Review of Relevant Physiology for Interpretation of Cardiac MR Imaging and CT.

    PubMed

    Sheth, Pooja J; Danton, Gary H; Siegel, Yoel; Kardon, Richard E; Infante, Juan C; Ghersin, Eduard; Fishman, Joel E

    2015-01-01

    Cardiac computed tomography (CT) and magnetic resonance (MR) imaging provide clinicians with important insights into cardiac physiology and pathology. However, not all radiologists understand the language and concepts of cardiac physiology that are used daily by cardiologists. This review article covers basic cardiac physiology as it relates to cardiac CT and MR imaging. Topics include a review of the cardiac cycle and left ventricular pressure-volume loops as they relate to different pathologic states, evaluation of cardiac function, and calculation of key parameters such as left ventricular volumes and the ejection fraction. The hemodynamics of cardiac shunts are covered, with an emphasis on factors important to cardiologists, including the ratio of pulmonary flow to systemic flow. Additionally, valvular physiologic function is reexamined, with a focus on understanding pressure gradients within the heart and also the changes associated with valvular pathologic conditions, including measurement of regurgitant fractions in patients with valvular insufficiency. Understanding these basic concepts will help radiologists tailor the reporting of cardiac studies to clinically relevant information.

  6. Video imaging of cardiac transmembrane activity

    NASA Astrophysics Data System (ADS)

    Baxter, William T.; Davidenko, Jorge; Cabo, Candido; Jalife, Jose

    1994-05-01

    High resolution movies of transmembrane electrical activity in thin (0.5 mm) slices of sheep epicardial muscle were recorded by optical imaging with voltage-sensitive dyes and a CCD video camera. Activity was monitored at approximately 65,000 picture elements per 2 cm2 tissue for several seconds at a 16 msec sampling rate. Simple image processing operations permitted visualization and analysis of the optical signal, while isochrome maps depicted complex patterns of propagation. Maps of action potential duration and regional intermittent conduction block showed that even these small preparations may exhibit considerable spatial heterogeneity. Self-sustaining reentrant activity in the form of spiral waves was consistently initiated and observed either drifting across the tissue or anchored to small heterogeneities. The current limitations of video optical mappings are a low signal-to- noise ratio and low temporal resolution. The advantages include high spatial resolution and direct correlation of electrical activity with anatomy. Video optical mapping permits the analysis of the electrophysiological properties of any region of the preparation during both regular stimulation and reentrant activation, providing a useful tool for studying cardiac arrhythmias.

  7. Multimodality Imaging in Cardiac Sarcoidosis: Is There a Winner?

    PubMed

    Perez, Irving E; Garcia, Mario J; Taub, Cynthia C

    2016-01-01

    Sarcoidosis is a multisystem granulomatous disease of unknown cause that can affect the heart. Cardiac sarcoidosis may be present in as many as 25% of patients with systemic sarcoidosis, and it is frequently underdiagnosed. The early and accurate diagnosis of myocardial involvement is challenging. Advanced imaging techniques play important roles in the diagnosis and management of patients with cardiac sarcoidosis.

  8. Quantitative image quality evaluation for cardiac CT reconstructions

    NASA Astrophysics Data System (ADS)

    Tseng, Hsin-Wu; Fan, Jiahua; Kupinski, Matthew A.; Balhorn, William; Okerlund, Darin R.

    2016-03-01

    Maintaining image quality in the presence of motion is always desirable and challenging in clinical Cardiac CT imaging. Different image-reconstruction algorithms are available on current commercial CT systems that attempt to achieve this goal. It is widely accepted that image-quality assessment should be task-based and involve specific tasks, observers, and associated figures of merits. In this work, we developed an observer model that performed the task of estimating the percentage of plaque in a vessel from CT images. We compared task performance of Cardiac CT image data reconstructed using a conventional FBP reconstruction algorithm and the SnapShot Freeze (SSF) algorithm, each at default and optimal reconstruction cardiac phases. The purpose of this work is to design an approach for quantitative image-quality evaluation of temporal resolution for Cardiac CT systems. To simulate heart motion, a moving coronary type phantom synchronized with an ECG signal was used. Three different percentage plaques embedded in a 3 mm vessel phantom were imaged multiple times under motion free, 60 bpm, and 80 bpm heart rates. Static (motion free) images of this phantom were taken as reference images for image template generation. Independent ROIs from the 60 bpm and 80 bpm images were generated by vessel tracking. The observer performed estimation tasks using these ROIs. Ensemble mean square error (EMSE) was used as the figure of merit. Results suggest that the quality of SSF images is superior to the quality of FBP images in higher heart-rate scans.

  9. High-resolution breath-hold cardiac magnetic resonance imaging

    SciTech Connect

    Liu, Yu.

    1993-01-01

    This dissertation work is composed of investigations of three methods for fast cardiac magnetic resonance imaging (MRI). These methods include (1) 2D breath-hold magnetization prepared gradient echo and fast spin-echo (FSE) cardiac imaging, (2) 3D breath-hold magnetization prepared gradient echo cardiac imaging, and (3) real-time monitoring, feedback, and triggering for breath-hold MRI. The hypothesis of this work is that high resolution 2D and 3D magnetic resonance data sets for the heart can be acquired with the combination of magnetization prepared blood suppression for gradient echo techniques and accurate breath-holding methods. The 2D method included development of magnetic resonance data acquisition for cardiac imaging. The acquisition time is within a single breath-hold of 16 seconds (assuming heart 60/min). The data acquisition is synchronized with the electrocardiogram signal. Based on consistent observations of specific small cardiac structures like the papillary muscle, trabeculae, moderator band, and coronary vessels in studies of normal volunteers, the image quality represents a significant improvement over that obtained with fast imaging methods previously. To further improve the image quality provided by the 2D method, the first 3D cardiac MRI technique was developed. This method provides even better spatial resolution for cardiac images, with a voxel size of 1.09 [times] 2.19 [times] 4 mm[sup 3]. A 3D acquisition is completed in 8 breath-holds. The data acquisition for 3D cardiac imaging requires a consistent breath-hold position to avoid respiratory artifacts. To improve the reliability of the 3DFT acquisition, a new technique called MR breath-hold feedback was developed to provide reproducible breathholding. The diaphragm location is used as the index for breath-hold reproducibility measurement. The range of the diaphragm displacement in different breath-hold is reduced from 8.3 mm without the technique, to 1.3 mm with the technique.

  10. Coherent hybrid electromagnetic field imaging

    DOEpatents

    Cooke, Bradly J.; Guenther, David C.

    2008-08-26

    An apparatus and corresponding method for coherent hybrid electromagnetic field imaging of a target, where an energy source is used to generate a propagating electromagnetic beam, an electromagnetic beam splitting means to split the beam into two or more coherently matched beams of about equal amplitude, and where the spatial and temporal self-coherence between each two or more coherently matched beams is preserved. Two or more differential modulation means are employed to modulate each two or more coherently matched beams with a time-varying polarization, frequency, phase, and amplitude signal. An electromagnetic beam combining means is used to coherently combine said two or more coherently matched beams into a coherent electromagnetic beam. One or more electromagnetic beam controlling means are used for collimating, guiding, or focusing the coherent electromagnetic beam. One or more apertures are used for transmitting and receiving the coherent electromagnetic beam to and from the target. A receiver is used that is capable of square-law detection of the coherent electromagnetic beam. A waveform generator is used that is capable of generation and control of time-varying polarization, frequency, phase, or amplitude modulation waveforms and sequences. A means of synchronizing time varying waveform is used between the energy source and the receiver. Finally, a means of displaying the images created by the interaction of the coherent electromagnetic beam with target is employed.

  11. Accelerating Dynamic Cardiac MR Imaging Using Structured Sparse Representation

    PubMed Central

    Cai, Nian; Wang, Shengru; Zhu, Shasha

    2013-01-01

    Compressed sensing (CS) has produced promising results on dynamic cardiac MR imaging by exploiting the sparsity in image series. In this paper, we propose a new method to improve the CS reconstruction for dynamic cardiac MRI based on the theory of structured sparse representation. The proposed method user the PCA subdictionaries for adaptive sparse representation and suppresses the sparse coding noise to obtain good reconstructions. An accelerated iterative shrinkage algorithm is used to solve the optimization problem and achieve a fast convergence rate. Experimental results demonstrate that the proposed method improves the reconstruction quality of dynamic cardiac cine MRI over the state-of-the-art CS method. PMID:24454528

  12. Introduction to cardiac neuronal imaging: a clinical perspective.

    PubMed

    Jacobson, Arnold F; Narula, Jagat

    2015-06-01

    Procedures for noninvasive and minimally invasive imaging of cardiac neurons and neuronal function using radiolabeled compounds were developed in the second half of the 20th century. The foundation for these procedures was several centuries of research that identified the structural components of the autonomic nervous system and explored the means by which neurotransmitters such as acetylcholine and norepinephrine contributed to neuronal control of target organ effector cells. This article provides a brief clinical overview of modern approaches to the assessment of cardiac neurons as an introduction to the in-depth articles on the current status of cardiac neuronal imaging presented in this supplement. PMID:26033903

  13. Achieving high-value cardiac imaging: challenges and opportunities.

    PubMed

    Wiener, David H

    2014-01-01

    Cardiac imaging is under intense scrutiny as a contributor to health care costs, with multiple initiatives under way to reduce and eliminate inappropriate testing. Appropriate use criteria are valuable guides to selecting imaging studies but until recently have focused on the test rather than the patient. Patient-centered means are needed to define the true value of imaging for patients in specific clinical situations. This article provides a definition of high-value cardiac imaging. A paradigm to judge the efficacy of echocardiography in the absence of randomized controlled trials is presented. Candidate clinical scenarios are proposed in which echocardiography constitutes high-value imaging, as well as stratagems to increase the likelihood that high-value cardiac imaging takes place in those circumstances.

  14. Hybrid imaging technology: from dreams and vision to clinical devices.

    PubMed

    Patton, James A; Townsend, David W; Hutton, Brian F

    2009-07-01

    Early in the history of nuclear medicine imaging it was realized that the nature of physiological mechanisms associated with the use of radiotracers prevented the identification of anatomic structures with a high degree of accuracy. This limitation often created difficulties in accurate interpretations of acquired images and caused investigators to seek methods of obtaining accurate anatomic correlations. Initial work centered on the use of software tools to combine anatomic and physiological data. Limitations in the use of these techniques, coupled with the development and refinements of anatomic imaging technologies (computed tomography [CT] and magnetic resonance imaging [MRI]), resulted in the development of hybrid imaging systems that combined CT with single-photon emission computed tomography (SPECT) and positron emission tomography (PET). With these hybrid systems, the images can be viewed separately or combined in a fused presentation for direct image correlation of anatomy and physiology. Presently, SPECT systems are available either with nondiagnostic CT capability for attenuation correction and image correlation, or with fully diagnostic CT capability, providing complementary diagnostic information. Equivalently, PET systems with diagnostic CT capability that provide high-resolution physiological and anatomic images are also now commercially available. These systems continue to evolve with the development of new detector materials and data acquisition and image processing technology. The widespread use of SPECT in cardiac imaging has resulted in the development of several new approaches to data acquisition and these new systems currently have either CT capability or the addition of this technology is planned in the future. The development and commercial availability of hybrid imaging systems has provided physicians with important new tools that significantly improve the diagnostic, staging, and treatment planning processes that are now available for

  15. Evaluation of respiratory and cardiac motion correction schemes in dual gated PET/CT cardiac imaging

    SciTech Connect

    Lamare, F. Fernandez, P.; Le Maitre, A.; Visvikis, D.; Dawood, M.; Schäfers, K. P.; Rimoldi, O. E.

    2014-07-15

    Purpose: Cardiac imaging suffers from both respiratory and cardiac motion. One of the proposed solutions involves double gated acquisitions. Although such an approach may lead to both respiratory and cardiac motion compensation there are issues associated with (a) the combination of data from cardiac and respiratory motion bins, and (b) poor statistical quality images as a result of using only part of the acquired data. The main objective of this work was to evaluate different schemes of combining binned data in order to identify the best strategy to reconstruct motion free cardiac images from dual gated positron emission tomography (PET) acquisitions. Methods: A digital phantom study as well as seven human studies were used in this evaluation. PET data were acquired in list mode (LM). A real-time position management system and an electrocardiogram device were used to provide the respiratory and cardiac motion triggers registered within the LM file. Acquired data were subsequently binned considering four and six cardiac gates, or the diastole only in combination with eight respiratory amplitude gates. PET images were corrected for attenuation, but no randoms nor scatter corrections were included. Reconstructed images from each of the bins considered above were subsequently used in combination with an affine or an elastic registration algorithm to derive transformation parameters allowing the combination of all acquired data in a particular position in the cardiac and respiratory cycles. Images were assessed in terms of signal-to-noise ratio (SNR), contrast, image profile, coefficient-of-variation (COV), and relative difference of the recovered activity concentration. Results: Regardless of the considered motion compensation strategy, the nonrigid motion model performed better than the affine model, leading to higher SNR and contrast combined with a lower COV. Nevertheless, when compensating for respiration only, no statistically significant differences were

  16. Multimodality 3-Dimensional Image Integration for Congenital Cardiac Catheterization

    PubMed Central

    2014-01-01

    Cardiac catheterization procedures for patients with congenital and structural heart disease are becoming more complex. New imaging strategies involving integration of 3-dimensional images from rotational angiography, magnetic resonance imaging (MRI), computerized tomography (CT), and transesophageal echocardiography (TEE) are employed to facilitate these procedures. We discuss the current use of these new 3D imaging technologies and their advantages and challenges when used to guide complex diagnostic and interventional catheterization procedures in patients with congenital heart disease. PMID:25114757

  17. [Update on cardiac imaging techniques. Echocardiography, cardiac magnetic resonance and multidetector computed tomography].

    PubMed

    de Vinuesa, Pastora Gallego García; del Castillo, Sonia Velasco; Torres, Río Aguilar; Bardera, Juan C Paré

    2008-02-01

    This review of progress in cardiac imaging techniques summarizes the most significant development reported in the last year on different echocardiographic techniques and their application in a range of settings, from the treatment of heart failure to their use in intraoperative monitoring and guiding interventional procedures. Large sections are devoted to recent developments in three-dimensional imaging and, because of its clinical importance, to magnetic resonance imaging. Finally, there is a comprehensive update on the use of multidetector computed tomography in cardiology.

  18. Optimizing cardiac MR imaging: practical remedies for artifacts.

    PubMed

    Saremi, Farhood; Grizzard, John D; Kim, Raymond J

    2008-01-01

    With ongoing technical advances in magnetic resonance (MR) imaging, the clinical demand for cardiac MR evaluations has been increasing. Cardiac MR imaging techniques have evolved from traditional spin-echo sequences to breath-hold spoiled gradient-echo and balanced steady-state free precession sequences. The most recently developed techniques allow evaluation of myocardial function, perfusion, and viability; coronary angiography; flow quantification; and standard morphologic assessments. However, even with the most sophisticated acquisition techniques, artifacts commonly occur at cardiac MR imaging. Knowledge of the origin, imaging appearance, and significance of these artifacts is essential to avoid misinterpreting them as true lesions. Some artifacts are caused by simple errors in positioning of the patient, coil, or electrocardiographic leads; radiofrequency interference from nearby electronic equipment; or metallic objects within the magnetic field. Others are directly related to a specific MR imaging sequence or technique. Accelerated imaging techniques such as parallel imaging, which are used to shorten acquisition and breath-hold times in cardiac evaluations, are particularly vulnerable to artifacts. If an artifact severely degrades image quality, the acquisition should be repeated with appropriate adjustments to decrease or eliminate the problem.

  19. Automatic reading of hybridization filter images.

    PubMed

    Audic, S; Zanetti, G

    1995-10-01

    We describe a new technique for the automatic detection and characterization, in terms of location, size and intensity, of positive hybridization spots on hybridization filter images. We will also discuss how this information can be used to reconstruct the spot deposition pattern on the filter and thus identify the spots. The part of the algorithm dedicated to the detection of spots is derived from a technique used in astronomy for the automatic recognition of galaxies on photographic plates. This technique has been modified so that it becomes able to cope with the strongly varying background typical of hybridization filter images. The technique does not require any human intervention.

  20. Assessment of Cardiac Sarcoidosis with Advanced Imaging Modalities

    PubMed Central

    Akasaka, Takashi

    2014-01-01

    Sarcoidosis is a chronic systemic disease of unknown etiology that is characterized by the presence of noncaseating epithelioid granulomas, usually in multiple organs. Several studies have shown that sarcoidosis might be the result of an exaggerated granulomatous reaction after exposure to unidentified antigens in genetically susceptible individuals. Cardiac involvement may occur and lead to an adverse outcome: the heart mechanics will be affected and that causes ventricular failure, and the cardiac electrical system will be disrupted and lead to third degree atrioventricular block, malignant ventricular tachycardia, and sudden cardiac death. Thus, early diagnosis and treatment of this potentially devastating disease is critically important. However, sensitive and accurate imaging modalities have not been established. Recent studies have demonstrated the promising potential of cardiac magnetic resonance imaging (MRI) and 18F-fluoro-2-deoxyglucose positron emission tomography (18F-FDG PET) in the diagnosis and assessment of cardiac sarcoidosis (CS). In this review, we discuss the epidemiology, etiology, histological findings, and clinical features of sarcoidosis. We also introduce advanced imaging including 18F-FDG PET and cardiac MRI as more reliable diagnostic modalities for CS. PMID:25250336

  1. Functional imaging as an indicator of diagnostic information in cardiac magnetic-resonance images

    NASA Astrophysics Data System (ADS)

    Klingler, Joseph W.; Andrews, Lee T.; Begeman, Michael S.; Zeiss, Jacob; Leighton, Richard F.

    1990-08-01

    Magnetic Resonance (MR) images of the human heart provide three dimensional geometric information about the location of cardiac structures throughout the cardiac cycle. Analysis of this four dimensional data set allows detection of abnormal cardiac function related to the presence of coronary artery disease. To assist in this analysis, quantitative measurements of cardiac performance are made from the MR data including ejection fractions, regional wall motion and myocardial wall thickening. Analysis of cardiac performance provided by quantitative analysis of MR data can be aided by computer graphics presentation techniques. Two and three dimensional functional images are computed to indicate regions of abnormality based on the previous methods. The two dimensional images are created using color graphics overlays on the original MR image to represent performance. Polygon surface modeling techniques are used to represent data which is three dimensional, such as blood pool volumes. The surface of these images are color encoded by regional ejection fraction, wall motion or wall thickening. A functional image sequence is constructed at each phase of the cardiac cycle and displayed as a movie loop for review by the physician. Selection of a region on the functional image allows visual interpretation of the original MR images, graphical plots of cardiac function and tabular results. Color encoding is based on absolute measurements and comparison to standard normal templates of cardiac performance.

  2. Cardiac Sarcoidosis: Clinical Manifestations, Imaging Characteristics, and Therapeutic Approach

    PubMed Central

    Houston, Brian A; Mukherjee, Monica

    2014-01-01

    Sarcoidosis is a multi-system disease pathologically characterized by the accumulation of T-lymphocytes and mononuclear phagocytes into the sine qua non pathologic structure of the noncaseating granuloma. Cardiac involvement remains a key source of morbidity and mortality in sarcoidosis. Definitive diagnosis of cardiac sarcoidosis, particularly early enough in the disease course to provide maximal therapeutic impact, has proven a particularly difficult challenge. However, major advancements in imaging techniques have been made in the last decade. Advancements in imaging modalities including echocardiography, nuclear spectroscopy, positron emission tomography, and magnetic resonance imaging all have improved our ability to diagnose cardiac sarcoidosis, and in many cases to provide a more accurate prognosis and thus targeted therapy. Likewise, therapy for cardiac sarcoidosis is beginning to advance past a “steroids-only” approach, as novel immunosuppressant agents provide effective steroid-sparing options. The following focused review will provide a brief discussion of the epidemiology and clinical presentation of cardiac sarcoidosis followed by a discussion of up-to-date imaging modalities employed in its assessment and therapeutic approaches. PMID:25452702

  3. Mapping cardiac surface mechanics with structured light imaging

    PubMed Central

    Laughner, Jacob I.; Zhang, Song; Li, Hao; Shao, Connie C.

    2012-01-01

    Cardiovascular disease often manifests as a combination of pathological electrical and structural heart remodeling. The relationship between mechanics and electrophysiology is crucial to our understanding of mechanisms of cardiac arrhythmias and the treatment of cardiac disease. While several technologies exist for describing whole heart electrophysiology, studies of cardiac mechanics are often limited to rhythmic patterns or small sections of tissue. Here, we present a comprehensive system based on ultrafast three-dimensional (3-D) structured light imaging to map surface dynamics of whole heart cardiac motion. Additionally, we introduce a novel nonrigid motion-tracking algorithm based on an isometry-maximizing optimization framework that forms correspondences between consecutive 3-D frames without the use of any fiducial markers. By combining our 3-D imaging system with nonrigid surface registration, we are able to measure cardiac surface mechanics at unprecedented spatial and temporal resolution. In conclusion, we demonstrate accurate cardiac deformation at over 200,000 surface points of a rabbit heart recorded at 200 frames/s and validate our results on highly contrasting heart motions during normal sinus rhythm, ventricular pacing, and ventricular fibrillation. PMID:22796539

  4. Overview of left ventricular outpouchings on cardiac magnetic resonance imaging

    PubMed Central

    Kumar, Sanjeev

    2015-01-01

    Left ventricular outpouchings commonly include aneurysm, pseudoaneurysm, and diverticulum and are now being increasingly detected on imaging. Distinction between these entities is of prime importance to guide proper management as outcomes for these entities differ substantially. Chest radiograph is usually nonspecific in their diagnosis. Echocardiography, multi-detector computed tomography evaluation and angiography are helpful in the diagnosis with their inherit limitations. Cardiac magnetic resonance imaging (MRI) is emerging as a very useful tool that allows simultaneous anatomical and functional evaluation along with tissue characterization, which has diagnostic, theraputic and prognostic implications. This article gives an overview of left ventricular outpouchings with special emphasis on their differentiation using cardiac MRI. PMID:26675616

  5. Role of radionuclide cardiac imaging in coronary artery bypass surgery

    SciTech Connect

    Iskandrian, A.S.; Heo, J.; Mostel, E.

    1987-01-01

    The main applications of cardiac nuclear imaging in coronary artery bypass surgery include: patient selection, prediction of improvement in resting LV function after revascularization, diagnosis of perioperative myocardial infarction, assessment of the results of revascularization, evaluation of new or recurrent symptoms, and in risk stratification. Proper understanding of which test to be used, when, and why may be important to optimize patient management.

  6. Towards Depth-Resolved Optical Imaging of Cardiac Electrical Activity.

    PubMed

    Walton, Richard D; Bernus, Olivier

    2015-01-01

    The spatiotemporal dynamics of arrhythmias are likely to be complex three-dimensional phenomena. Yet, the lack of high-resolution three-dimensional imaging techniques, both in the clinic and the experimental lab, limits our ability to better understand the mechanisms of such arrhythmias. Optical mapping using voltage-sensitive dyes is a widely used tool in experimental electrophysiology. It has been known for decades that even in its most basic application, epi-fluorescence, the optical signal contains information from within a certain intramural volume. Understanding of this fundamental property of optical signals has paved the way towards novel three-dimensional optical imaging techniques. Here, we review our current understanding of the three-dimensional nature of optical signals; how penetration depths of cardiac optical imaging can be improved by using novel imaging modalities and finally, we highlight new techniques inspired from optical tomography and aiming at full depth-resolved optical mapping of cardiac electrical activity. PMID:26238062

  7. Intraocular lymphoma after cardiac transplantation: magnetic resonance imaging findings.

    PubMed

    Kim, Yi Kyung; Kim, Hyung-Jin; Woo, Kyung In; Kim, Yoon-Duck

    2013-01-01

    We report a case of intraocular lymphoma in a 65-year-old man, 15 months after cardiac transplantation. On Magnetic Resonance (MR) images, the iris and the anterior chamber of the right eye were found to be involved with an enhancing soft-tissue lesion. To our knowledge, this is the first case of post-transplantation intraocular lymphoma evaluated with MR imaging. PMID:23323042

  8. New methods for image guidance and visualization for cardiac procedures

    NASA Astrophysics Data System (ADS)

    Guttman, Michael A.; McVeigh, Elliot R.

    2007-03-01

    Interventional cardiac MRI has been undergoing rapid development because of the availability of MRI compatible interventional catheters, and the increased performance of the MRI systems. Intravascular techniques do not require an open access scanner, and hence higher imaging performance during procedures can be achieved. Now, with the availability of a short, relatively open cylindrical bore scanner high imaging performance is also available to guide direct surgical procedures.

  9. Gated magnetic resonance imaging of congenital cardiac malformations

    SciTech Connect

    Fletcher, B.D.; Jocobstein, M.D.; Nelson, A.D.; Riemenschneider, T.A.; Alfidi, R.J.

    1984-01-01

    Magnetic resonance (MR) images of a variety of cardiac malformations in 19 patients aged 1 week to 33 years were obtained using pulse plethysmographic- or ECG-gated spin echo pulse sequences. Coronal, axial, and sagittal images displaying intracardiac structures with excellent spatial and contrast resolution were acquired during systole or diastole. It is concluded that MR will be a valuable noninvasive method of diagnosing congenital heart disease.

  10. Imaging techniques for cardiac strain and deformation: comparison of echocardiography, cardiac magnetic resonance and cardiac computed tomography.

    PubMed

    Tee, Michael; Noble, J Alison; Bluemke, David A

    2013-02-01

    Myocardial function assessment is essential for determining the health of the myocardium. Global assessment of myocardial function is widely performed (by estimating the ejection fraction), but many common cardiac diseases initially affect the myocardium on a regional, rather than global basis. Regional myocardial wall motion can be quantified using myocardial strain analysis (a normalized measure of deformation). Myocardial strain can be measured in terms of three normal strains (longitudinal strain, radial strain and circumferential) and six shear strains. Cardiac MRI (cMRI) is usually considered the reference standard for measurement of myocardial strain. The most common cMRI method, termed tagged cMRI, allows full, 3D assessment of regional strain. However, due to its complexity and lengthy times for analysis, tagged cMRI is not usually used outside of academic centers. Tagged cMRI is also primarily used only in research studies. Echocardiography combined with tissue Doppler imaging or a speckle tracking technique is now widely available in the clinical setting. Myocardial strain measurement by echocardiography shows reasonable agreement with cMRI. Limited standardization and differences between vendors represent current limitations of the technique. Cardiac computed tomography (CCT) is the newest and most rapidly growing modality for noninvasive imaging of the heart. While CCT studies are most commonly applied to assess the coronary arteries, CCT is easily adapted to provide functional information for both the left and right ventricles. New methods for CCT assessment of regional myocardial function are being developed. This review outlines the current literature on imaging techniques related to cardiac strain analysis and discusses the strengths and weaknesses of various methods for myocardial strain analysis.

  11. Temporal resolution improvement using PICCS in MDCT cardiac imaging.

    PubMed

    Chen, Guang-Hong; Tang, Jie; Hsieh, Jiang

    2009-06-01

    The current paradigm for temporal resolution improvement is to add more source-detector units and/or increase the gantry rotation speed. The purpose of this article is to present an innovative alternative method to potentially improve temporal resolution by approximately a factor of 2 for all MDCT scanners without requiring hardware modification. The central enabling technology is a most recently developed image reconstruction method: Prior image constrained compressed sensing (PICCS). Using the method, cardiac CT images can be accurately reconstructed using the projection data acquired in an angular range of about 120 degrees, which is roughly 50% of the standard short-scan angular range (approximately 240 degrees for an MDCT scanner). As a result, the temporal resolution of MDCT cardiac imaging can be universally improved by approximately a factor of 2. In order to validate the proposed method, two in vivo animal experiments were conducted using a state-of-the-art 64-slice CT scanner (GE Healthcare, Waukesha, WI) at different gantry rotation times and different heart rates. One animal was scanned at heart rate of 83 beats per minute (bpm) using 400 ms gantry rotation time and the second animal was scanned at 94 bpm using 350 ms gantry rotation time, respectively. Cardiac coronary CT imaging can be successfully performed at high heart rates using a single-source MDCT scanner and projection data from a single heart beat with gantry rotation times of 400 and 350 ms. Using the proposed PICCS method, the temporal resolution of cardiac CT imaging can be effectively improved by approximately a factor of 2 without modifying any scanner hardware. This potentially provides a new method for single-source MDCT scanners to achieve reliable coronary CT imaging for patients at higher heart rates than the current heart rate limit of 70 bpm without using the well-known multisegment FBP reconstruction algorithm. This method also enables dual-source MDCT scanner to achieve higher

  12. Hybrid SPECT/CT imaging in neurology.

    PubMed

    Ciarmiello, Andrea; Giovannini, Elisabetta; Meniconi, Martina; Cuccurullo, Vincenzo; Gaeta, Maria Chiara

    2014-01-01

    In recent years, the SPECT/CT hybrid modality has led to a rapid development of imaging techniques in nuclear medicine, opening new perspectives for imaging staff and patients as well. However, while, the clinical role of positron emission tomography-computed tomography (PET-CT) is well consolidated, the diffusion and the consequent value of single-photon emission tomography-computed tomography (SPECT-CT) has yet to be weighed, Hence, there is a need for a careful analysis, comparing the "potential" benefits of the hybrid modality with the "established" ones of the standalone machine. The aim of this article is to analyze the impact of this hybrid tool on the diagnosis of diseases of the central nervous system, comparing strengths and weaknesses of both modalities through the use of SWOT analysis. PMID:25143053

  13. Images as drivers of progress in cardiac computational modelling

    PubMed Central

    Lamata, Pablo; Casero, Ramón; Carapella, Valentina; Niederer, Steve A.; Bishop, Martin J.; Schneider, Jürgen E.; Kohl, Peter; Grau, Vicente

    2014-01-01

    Computational models have become a fundamental tool in cardiac research. Models are evolving to cover multiple scales and physical mechanisms. They are moving towards mechanistic descriptions of personalised structure and function, including effects of natural variability. These developments are underpinned to a large extent by advances in imaging technologies. This article reviews how novel imaging technologies, or the innovative use and extension of established ones, integrate with computational models and drive novel insights into cardiac biophysics. In terms of structural characterization, we discuss how imaging is allowing a wide range of scales to be considered, from cellular levels to whole organs. We analyse how the evolution from structural to functional imaging is opening new avenues for computational models, and in this respect we review methods for measurement of electrical activity, mechanics and flow. Finally, we consider ways in which combined imaging and modelling research is likely to continue advancing cardiac research, and identify some of the main challenges that remain to be solved. PMID:25117497

  14. Diagnosing cardiac disease during pregnancy: imaging modalities.

    PubMed

    Ntusi, Ntobeko A; Samuels, Petronella; Moosa, Sulaiman; Mocumbi, Ana O

    2016-01-01

    Pregnant women with known or suspected cardiovascular disease (CVD) often require cardiovascular imaging during pregnancy. The accepted maximum limit of ionising radiation exposure to the foetus during pregnancy is a cumulative dose of 5 rad. Concerns related to imaging modalities that involve ionising radiation include teratogenesis, mutagenesis and childhood malignancy. Importantly, no single imaging study approaches this cautionary dose of 5 rad (50 mSv or 50 mGy). Diagnostic imaging procedures that may be used in pregnancy include chest radiography, fluoroscopy, echocardiography, invasive angiography, cardiovascular computed tomography, computed tomographic pulmonary angiography, cardiovascular magnetic resonance (CMR) and nuclear techniques. Echocardiography and CMR appear to be completely safe in pregnancy and are not associated with any adverse foetal effects, provided there are no general contra-indications to MR imaging. Concerns related to safety of imaging tests must be balanced against the importance of accurate diagnosis and thorough assessment of the pathological condition. Decisions about imaging in pregnancy are premised on understanding the physiology of pregnancy, understanding basic concepts of ionising radiation, the clinical manifestations of existent CVD in pregnancy and features of new CVD. The cardiologist/physician must understand the indications for and limitations of, and the potential harmful effects of each test during pregnancy. Current evidence suggests that a single cardiovascular radiological study during pregnancy is safe and should be undertaken at all times when clinically justified. In this article, the different imaging modalities are reviewed in terms of how they work, how safe they are and what their clinical utility in pregnancy is. Furthermore, the safety of contrast agents in pregnancy is also reviewed. PMID:27213857

  15. Miniature hybrid optical imaging lens

    DOEpatents

    Sitter, D.N. Jr.; Simpson, M.L.

    1997-10-21

    A miniature lens system that corrects for imaging and chromatic aberrations is disclosed, the lens system being fabricated from primarily commercially-available components. A first element at the input to a lens housing is an aperture stop. A second optical element is a refractive element with a diffractive element closely coupled to, or formed a part of, the rear surface of the refractive element. Spaced closely to the diffractive element is a baffle to limit the area of the image, and this is closely followed by a second refractive lens element to provide the final correction. The image, corrected for aberrations exits the last lens element to impinge upon a detector plane were is positioned any desired detector array. The diffractive element is fabricated according to an equation that includes, as variables, the design wavelength, the index of refraction and the radius from an optical axis of the lens system components. 2 figs.

  16. Miniature hybrid optical imaging lens

    DOEpatents

    Sitter, Jr., David N.; Simpson, Marc L.

    1997-01-01

    A miniature lens system that corrects for imaging and chromatic aberrations, the lens system being fabricated from primarily commercially-available components. A first element at the input to a lens housing is an aperture stop. A second optical element is a refractive element with a diffractive element closely coupled to, or formed a part of, the rear surface of the refractive element. Spaced closely to the diffractive element is a baffle to limit the area of the image, and this is closely followed by a second refractive lens element to provide the final correction. The image, corrected for aberrations exits the last lens element to impinge upon a detector plane were is positioned any desired detector array. The diffractive element is fabricated according to an equation that includes, as variables, the design wavelength, the index of refraction and the radius from an optical axis of the lens system components.

  17. Petascale computation performance of lightweight multiscale cardiac models using hybrid programming models.

    PubMed

    Pope, Bernard J; Fitch, Blake G; Pitman, Michael C; Rice, John J; Reumann, Matthias

    2011-01-01

    Future multiscale and multiphysics models must use the power of high performance computing (HPC) systems to enable research into human disease, translational medical science, and treatment. Previously we showed that computationally efficient multiscale models will require the use of sophisticated hybrid programming models, mixing distributed message passing processes (e.g. the message passing interface (MPI)) with multithreading (e.g. OpenMP, POSIX pthreads). The objective of this work is to compare the performance of such hybrid programming models when applied to the simulation of a lightweight multiscale cardiac model. Our results show that the hybrid models do not perform favourably when compared to an implementation using only MPI which is in contrast to our results using complex physiological models. Thus, with regards to lightweight multiscale cardiac models, the user may not need to increase programming complexity by using a hybrid programming approach. However, considering that model complexity will increase as well as the HPC system size in both node count and number of cores per node, it is still foreseeable that we will achieve faster than real time multiscale cardiac simulations on these systems using hybrid programming models.

  18. Multimodality cardiac imaging in Turner syndrome.

    PubMed

    Mortensen, Kristian H; Gopalan, Deepa; Nørgaard, Bjarne L; Andersen, Niels H; Gravholt, Claus H

    2016-06-01

    Congenital and acquired cardiovascular diseases contribute significantly to the threefold elevated risk of premature death in Turner syndrome. A multitude of cardiovascular anomalies and disorders, many of which deleteriously impact morbidity and mortality, is frequently left undetected and untreated because of poor adherence to screening programmes and complex clinical presentations. Imaging is essential for timely and effective primary and secondary disease prophylaxis that may alleviate the severe impact of cardiovascular disease in Turner syndrome. This review illustrates how cardiovascular disease in Turner syndrome manifests in a complex manner that ranges in severity from incidental findings to potentially fatal anomalies. Recommendations regarding the use of imaging for screening and surveillance of cardiovascular disease in Turner syndrome are made, emphasising the key role of non-invasive and invasive cardiovascular imaging to the management of all patients with Turner syndrome.

  19. Bayesian learning for cardiac SPECT image interpretation.

    PubMed

    Sacha, Jarosław P; Goodenday, Lucy S; Cios, Krzysztof J

    2002-01-01

    In this paper, we describe a system for automating the diagnosis of myocardial perfusion from single-photon emission computerized tomography (SPECT) images of male and female hearts. Initially we had several thousand of SPECT images, other clinical data and physician-interpreter's descriptions of the images. The images were divided into segments based on the Yale system. Each segment was described by the physician as showing one of the following conditions: normal perfusion, reversible perfusion defect, partially reversible perfusion defect, fixed perfusion defect, defect showing reverse redistribution, equivocal defect or artifact. The physician's diagnosis of overall left ventricular (LV) perfusion, based on the above descriptions, categorizes a study as showing one or more of eight possible conditions: normal, ischemia, infarct and ischemia, infarct, reverse redistribution, equivocal, artifact or LV dysfunction. Because of the complexity of the task, we decided to use the knowledge discovery approach, consisting of these steps: problem understanding, data understanding, data preparation, data mining, evaluating the discovered knowledge and its implementation. After going through the data preparation step, in which we constructed normal gender-specific models of the LV and image registration, we ended up with 728 patients for whom we had both SPECT images and corresponding diagnoses. Another major contribution of the paper is the data mining step, in which we used several new Bayesian learning classification methods. The approach we have taken, namely the six-step knowledge discovery process has proven to be very successful in this complex data mining task and as such the process can be extended to other medical data mining projects.

  20. Cardiac anisotropy: is it negligible regarding noninvasive activation time imaging?

    PubMed

    Modre, Robert; Seger, Michael; Fischer, Gerald; Hintermüller, Christoph; Hayn, Dieter; Pfeifer, Bernhard; Hanser, Friedrich; Schreier, Günter; Tilg, Bernhard

    2006-04-01

    The aim of this study was to quantify the effect of cardiac anisotropy in the activation-based inverse problem of electrocardiography. Differences of the patterns of simulated body surface potential maps for isotropic and anisotropic conditions were investigated with regard to activation time (AT) imaging of ventricular depolarization. AT maps were estimated by solving the nonlinear inverse ill-posed problem employing spatio-temporal regularization. Four different reference AT maps (sinus rhythm, right-ventricular and septal pacing, accessory pathway) were calculated with a bidomain theory based anisotropic finite-element heart model in combination with a cellular automaton. In this heart model a realistic fiber architecture and conduction system was implemented. Although the anisotropy has some effects on forward solutions, effects on inverse solutions are small indicating that cardiac anisotropy might be negligible for some clinical applications (e.g., imaging of focal events) of our AT imaging approach. The main characteristic events of the AT maps were estimated despite neglected electrical anisotropy in the inverse formulation. The worst correlation coefficient of the estimated AT maps was 0.810 in case of sinus rhythm. However, all characteristic events of the activation pattern were found. The results of this study confirm our clinical validation studies of noninvasive AT imaging in which cardiac anisotropy was neglected.

  1. Automated Pointing of Cardiac Imaging Catheters

    PubMed Central

    Loschak, Paul M.; Brattain, Laura J.; Howe, Robert D.

    2013-01-01

    Intracardiac echocardiography (ICE) catheters enable high-quality ultrasound imaging within the heart, but their use in guiding procedures is limited due to the difficulty of manually pointing them at structures of interest. This paper presents the design and testing of a catheter steering model for robotic control of commercial ICE catheters. The four actuated degrees of freedom (4-DOF) are two catheter handle knobs to produce bi-directional bending in combination with rotation and translation of the handle. An extra degree of freedom in the system allows the imaging plane (dependent on orientation) to be directed at an object of interest. A closed form solution for forward and inverse kinematics enables control of the catheter tip position and the imaging plane orientation. The proposed algorithms were validated with a robotic test bed using electromagnetic sensor tracking of the catheter tip. The ability to automatically acquire imaging targets in the heart may improve the efficiency and effectiveness of intracardiac catheter interventions by allowing visualization of soft tissue structures that are not visible using standard fluoroscopic guidance. Although the system has been developed and tested for manipulating ICE catheters, the methods described here are applicable to any long thin tendon-driven tool (with single or bi-directional bending) requiring accurate tip position and orientation control. PMID:24683501

  2. Automated Pointing of Cardiac Imaging Catheters.

    PubMed

    Loschak, Paul M; Brattain, Laura J; Howe, Robert D

    2013-12-31

    Intracardiac echocardiography (ICE) catheters enable high-quality ultrasound imaging within the heart, but their use in guiding procedures is limited due to the difficulty of manually pointing them at structures of interest. This paper presents the design and testing of a catheter steering model for robotic control of commercial ICE catheters. The four actuated degrees of freedom (4-DOF) are two catheter handle knobs to produce bi-directional bending in combination with rotation and translation of the handle. An extra degree of freedom in the system allows the imaging plane (dependent on orientation) to be directed at an object of interest. A closed form solution for forward and inverse kinematics enables control of the catheter tip position and the imaging plane orientation. The proposed algorithms were validated with a robotic test bed using electromagnetic sensor tracking of the catheter tip. The ability to automatically acquire imaging targets in the heart may improve the efficiency and effectiveness of intracardiac catheter interventions by allowing visualization of soft tissue structures that are not visible using standard fluoroscopic guidance. Although the system has been developed and tested for manipulating ICE catheters, the methods described here are applicable to any long thin tendon-driven tool (with single or bi-directional bending) requiring accurate tip position and orientation control.

  3. Translational Paradigms in Scientific and Clinical Imaging of Cardiac Development

    PubMed Central

    Gregg, Chelsea L.; Butcher, Jonathan T.

    2015-01-01

    Congenital heart defects (CHD) are the most prevalent congenital disease with 45% of deaths resulting from a congenital defect are due to a cardiac malformation. Clinically significant CHD permit survival upon birth but may become immediately life threatening. Advances in surgical intervention have significantly reduced perinatal mortality, but the outcome for many malformations is bleak. Furthermore, patients living while tolerating a CHD often acquire additional complications due to the long-term systemic blood flow changes caused by even subtle anatomical abnormalities. Accurate diagnosis of defects during fetal development is critical for interventional planning and improving patient outcomes. Advances in quantitative, multi-dimensional imaging is necessary to uncover the basic scientific and clinically relevant morphogenetic changes and associated hemodynamic consequences influencing normal and abnormal heart development. Ultrasound is the most widely used clinical imaging technology for assessing fetal cardiac development. Ultrasound-based fetal assessment modalities include M-mode, 2D, and 3D/4D imaging. These datasets can be combined with computational fluid dynamics analysis to yield quantitative, volumetric and physiological data. Additional imaging modalities, however are available to study basic mechanisms of cardiogenesis, including optical coherence tomography, micro-computed tomography, and magnetic resonance imaging. Each imaging technology has its advantages and disadvantages regarding resolution, depth of penetration, soft tissue contrast considerations, and cost. In this review, we analyze the current clinical and scientific imaging technologies, research studies utilizing them, and appropriate animal models reflecting clinically relevant cardiogenesis and cardiac malformations. We conclude with discussing the translational impact and future opportunities for cardiovascular development imaging research. PMID:23897595

  4. Automatic image-based cardiac and respiratory cycle synchronization and gating of image sequences.

    PubMed

    Sundar, Hari; Khamene, Ali; Yatziv, Liron; Xu, Chenyang

    2009-01-01

    We propose a novel method to detect the current state of the quasi-periodic system from image sequences which in turn will enable us to synchronize/gate the image sequences to obtain images of the organ system at similar configurations. The method uses the cumulated phase shift in the spectral domain of successive image frames as a measure of the net motion of objects in the scene. The proposed method is applicable to 2D and 3D time varying sequences and is not specific to the imaging modality. We demonstrate its effectiveness on X-Ray Angiographic and Cardiac and Liver Ultrasound sequences. Knowledge of the current (cardiac or respiratory) phase of the system, opens up the possibility for a purely image based cardiac and respiratory gating scheme for interventional and radiotherapy procedures.

  5. Cardiac imaging in evaluating patients prone to sudden death

    PubMed Central

    Tamene, Ashenafi; Tholakanahalli, Venkatakrishna N.; Chandrashekhar, Y.

    2014-01-01

    Identifying subjects who are at risk for SCD and stratifying them correctly into low or high-risk groups is the holy grail of Cardiology. While imaging shows a lot of promise, it is plagued by the fact that most SCD occurs in relatively healthy subjects, a massive group who would not ordinarily be subjected to imaging. Left ventricular ejection fraction (LVEF) currently is our primary parameter for risk stratification for sudden cardiac death but is a poor marker with low sensitivity and specificity. Current data shows that sophisticated imaging with techniques, mainly Cardiac magnetic resonance Imaging (CMR), have the potential to identify novel high-risk markers underlying SCD, beyond ejection fraction. Imaging seems to further refine risk in patients with low LVEF as well as in those with normal EF; this is a major strength of advanced imaging. Clinical application has been slow and not fully prime time. It is important to remember that while promising, imaging techniques including CMR, have not been tested in rigorous prospective studies and thus have not as yet replaced EF as the gatekeeper to ICD implantation. PMID:24568832

  6. An integrated platform for image-guided cardiac resynchronization therapy

    NASA Astrophysics Data System (ADS)

    Ma, Ying Liang; Shetty, Anoop K.; Duckett, Simon; Etyngier, Patrick; Gijsbers, Geert; Bullens, Roland; Schaeffter, Tobias; Razavi, Reza; Rinaldi, Christopher A.; Rhode, Kawal S.

    2012-05-01

    Cardiac resynchronization therapy (CRT) is an effective procedure for patients with heart failure but 30% of patients do not respond. This may be due to sub-optimal placement of the left ventricular (LV) lead. It is hypothesized that the use of cardiac anatomy, myocardial scar distribution and dyssynchrony information, derived from cardiac magnetic resonance imaging (MRI), may improve outcome by guiding the physician for optimal LV lead positioning. Whole heart MR data can be processed to yield detailed anatomical models including the coronary veins. Cine MR data can be used to measure the motion of the LV to determine which regions are late-activating. Finally, delayed Gadolinium enhancement imaging can be used to detect regions of scarring. This paper presents a complete platform for the guidance of CRT using pre-procedural MR data combined with live x-ray fluoroscopy. The platform was used for 21 patients undergoing CRT in a standard catheterization laboratory. The patients underwent cardiac MRI prior to their procedure. For each patient, a MRI-derived cardiac model, showing the LV lead targets, was registered to x-ray fluoroscopy using multiple views of a catheter looped in the right atrium. Registration was maintained throughout the procedure by a combination of C-arm/x-ray table tracking and respiratory motion compensation. Validation of the registration between the three-dimensional (3D) roadmap and the 2D x-ray images was performed using balloon occlusion coronary venograms. A 2D registration error of 1.2 ± 0.7 mm was achieved. In addition, a novel navigation technique was developed, called Cardiac Unfold, where an entire cardiac chamber is unfolded from 3D to 2D along with all relevant anatomical and functional information and coupled to real-time device detection. This allowed more intuitive navigation as the entire 3D scene was displayed simultaneously on a 2D plot. The accuracy of the unfold navigation was assessed off-line using 13 patient data sets

  7. [Recommendations for training in cross-sectional cardiac imaging].

    PubMed

    Joffre, F; Boyer, L; Dacher, J-N; Gilard, M; Douek, P; Gueret, P

    2009-09-01

    The recent and future advancements that are known in the field of cardiac imaging imply an optimal training of the operators. This training concerns medical specialists whether originating from radiology or cardiology. The training of the medical specialists in cardiac imaging entitles 3 main essential steps: The basic training taking place within each specialty, allowing the fellow to get acquainted with the clinical and technical basics. The specialized training, delivered principally in post-residency. This training must include an upgrading of each specialty in the domain that does not concern it (a technical base for the cardiologist, a physio-pathological and clinical base for the radiologist). It must include a specific theoretical training covering all aspects of cardiac imaging as well as practical training in a certified training centre. The continuous medical training and maintenance of skills that allow a sustained activity in the field and the obligation to regularly participate in the actions of specific validated training. The different aspects of these rules are exposed in this chapter.

  8. Cardiac Magnetic Resonance Imaging in Ischemic Heart Disease

    PubMed Central

    Florian, A.; Jurcut, R.; Ginghina, C.; Bogaert, J.

    2011-01-01

    Cardiac magnetic resonance imaging (MRI) has emerged as a prime player in the clinical and preclinical detection of ischemic heart disease (IHD) as well in the prognosis assessment by offering a comprehensive approach for all spectrums of coronary artery disease (CAD) patients. The aim of this review is to provide the reader a state–of–the art on how the newest cardiac MRI techniques can be used to study IHD patients. In patients with suspected/stable CAD, functional and perfusion imaging both at rest and during vasodilatatory stress (adenosine, dypiridamole)/dobutamine stress can accurately depict ischemic myocardium secondary to significant coronary artery stenosis. In patients with acute MI, MRI is a robust tool for differentiating and sizing the jeopardized and the infarcted myocardium by using a combination of functional, edema, perfusion and Gd contrast imaging. Moreover, important prognostic factors like myocardial salvage, the presence of microvascular obstruction (MVO), post reperfusion myocardial hemorrhage, RV involvement and infarct related complications can be assessed in the same examination. In patients with chronic ischemic cardiomyopathy, the role of the MRI extends from diagnosis by means of Gadolinium contrast scar imaging to therapy and prognosis by functional assessment and viability testing with rest and dobutamine stress imaging. In all the circumstances mentioned, MRI derived information has been proven valuable in every day clinical decision making and prognosis assessment. Thus, MRI is becoming more and more an accepted alternative to other imaging modalities both in the acute and chronic setting. PMID:22514564

  9. The risks of inappropriateness in cardiac imaging.

    PubMed

    Picano, Eugenio

    2009-05-01

    The immense clinical and scientific benefits of cardiovascular imaging are well-established, but are also true that 30 to 50% of all examinations are partially or totally inappropriate. Marketing messages, high patient demand and defensive medicine, lead to the vicious circle of the so-called Ulysses syndrome. Mr. Ulysses, a typical middle-aged "worried-well" asymptomatic subject with an A-type coronary personality, a heavy (opium) smoker, leading a stressful life, would be advised to have a cardiological check-up after 10 years of war. After a long journey across imaging laboratories, he will have stress echo, myocardial perfusion scintigraphy, PET-CT, 64-slice CT, and adenosine-MRI performed, with a cumulative cost of >100 times a simple exercise-electrocardiography test and a cumulative radiation dose of >4,000 chest x-rays, with a cancer risk of 1 in 100. Ulysses is tired of useless examinations, exorbitant costs. unaffordable even by the richest society, and unacceptable risks. PMID:19543412

  10. The risks of inappropriateness in cardiac imaging.

    PubMed

    Picano, Eugenio

    2009-05-01

    The immense clinical and scientific benefits of cardiovascular imaging are well-established, but are also true that 30 to 50% of all examinations are partially or totally inappropriate. Marketing messages, high patient demand and defensive medicine, lead to the vicious circle of the so-called Ulysses syndrome. Mr. Ulysses, a typical middle-aged "worried-well" asymptomatic subject with an A-type coronary personality, a heavy (opium) smoker, leading a stressful life, would be advised to have a cardiological check-up after 10 years of war. After a long journey across imaging laboratories, he will have stress echo, myocardial perfusion scintigraphy, PET-CT, 64-slice CT, and adenosine-MRI performed, with a cumulative cost of >100 times a simple exercise-electrocardiography test and a cumulative radiation dose of >4,000 chest x-rays, with a cancer risk of 1 in 100. Ulysses is tired of useless examinations, exorbitant costs. unaffordable even by the richest society, and unacceptable risks.

  11. Nuclear magnetic resonance imaging in patients with cardiac pacing devices.

    PubMed

    Buendía, Francisco; Sánchez-Gómez, Juan M; Sancho-Tello, María J; Olagüe, José; Osca, Joaquín; Cano, Oscar; Arnau, Miguel A; Igual, Begoña

    2010-06-01

    Currently, nuclear magnetic resonance imaging is contraindicated in patients with a pacemaker or implantable cardioverter-defibrillator. This study was carried out because the potential risks in this situation need to be clearly defined. This prospective study evaluated clinical and electrical parameters before and after magnetic resonance imaging was performed in 33 patients (five with implantable cardioverter-defibrillators and 28 with pacemakers). In these patients, magnetic resonance imaging was considered clinically essential. There were no clinical complications. There was a temporary communication failure in two cases, sensing errors during imaging in two cases, and a safety signal was generated in one pacemaker at the maximum magnetic resonance frequency and output level. There were no technical restrictions on imaging nor were there any permanent changes in the performance of the cardiac pacing device. PMID:20515632

  12. Human torso phantom for imaging of heart with realistic modes of cardiac and respiratory motion

    DOEpatents

    Boutchko, Rostyslav; Balakrishnan, Karthikayan; Gullberg, Grant T; O& #x27; Neil, James P

    2013-09-17

    A human torso phantom and its construction, wherein the phantom mimics respiratory and cardiac cycles in a human allowing acquisition of medical imaging data under conditions simulating patient cardiac and respiratory motion.

  13. Image analysis in comparative genomic hybridization

    SciTech Connect

    Lundsteen, C.; Maahr, J.; Christensen, B.

    1995-01-01

    Comparative genomic hybridization (CGH) is a new technique by which genomic imbalances can be detected by combining in situ suppression hybridization of whole genomic DNA and image analysis. We have developed software for rapid, quantitative CGH image analysis by a modification and extension of the standard software used for routine karyotyping of G-banded metaphase spreads in the Magiscan chromosome analysis system. The DAPI-counterstained metaphase spread is karyotyped interactively. Corrections for image shifts between the DAPI, FITC, and TRITC images are done manually by moving the three images relative to each other. The fluorescence background is subtracted. A mean filter is applied to smooth the FITC and TRITC images before the fluorescence ratio between the individual FITC and TRITC-stained chromosomes is computed pixel by pixel inside the area of the chromosomes determined by the DAPI boundaries. Fluorescence intensity ratio profiles are generated, and peaks and valleys indicating possible gains and losses of test DNA are marked if they exceed ratios below 0.75 and above 1.25. By combining the analysis of several metaphase spreads, consistent findings of gains and losses in all or almost all spreads indicate chromosomal imbalance. Chromosomal imbalances are detected either by visual inspection of fluorescence ratio (FR) profiles or by a statistical approach that compares FR measurements of the individual case with measurements of normal chromosomes. The complete analysis of one metaphase can be carried out in approximately 10 minutes. 8 refs., 7 figs., 1 tab.

  14. Optical Imaging of Voltage and Calcium in Cardiac Cells & Tissues

    PubMed Central

    Herron, Todd J.; Lee, Peter; Jalife, José

    2012-01-01

    Cardiac optical mapping has proven to be a powerful technology for studying cardiovascular function and disease. The development and scientific impact of this methodology are well documented. Because of its relevance in cardiac research, this imaging technology advances at a rapid pace. Here we review technological and scientific developments during the past several years and look also towards the future. First we explore key components of a modern optical mapping setup, focusing on 1) new camera technologies, 2) powerful light-emitting-diodes (from ultraviolet to red) for illumination, 3) improved optical filter technology, 4) new synthetic and optogenetic fluorescent probes, 5) optical mapping with motion and contraction, 6) new multi-parametric optical mapping techniques and 7) photon scattering effects in thick tissue preparations. We then look at recent optical mapping studies in single cells, cardiomyocyte monolayers, atria and whole hearts. Finally, we briefly look into the possible future roles of optical mapping in the development of regenerative cardiac research, cardiac cell therapies, and molecular genetic advances. PMID:22343556

  15. Current-mode CMOS hybrid image sensor

    NASA Astrophysics Data System (ADS)

    Benyhesan, Mohammad Kassim

    Digital imaging is growing rapidly making Complimentary Metal-Oxide-Semi conductor (CMOS) image sensor-based cameras indispensable in many modern life devices like cell phones, surveillance devices, personal computers, and tablets. For various purposes wireless portable image systems are widely deployed in many indoor and outdoor places such as hospitals, urban areas, streets, highways, forests, mountains, and towers. However, the increased demand on high-resolution image sensors and improved processing features is expected to increase the power consumption of the CMOS sensor-based camera systems. Increased power consumption translates into a reduced battery life-time. The increased power consumption might not be a problem if there is access to a nearby charging station. On the other hand, the problem arises if the image sensor is located in widely spread areas, unfavorable to human intervention, and difficult to reach. Given the limitation of energy sources available for wireless CMOS image sensor, an energy harvesting technique presents a viable solution to extend the sensor life-time. Energy can be harvested from the sun light or the artificial light surrounding the sensor itself. In this thesis, we propose a current-mode CMOS hybrid image sensor capable of energy harvesting and image capture. The proposed sensor is based on a hybrid pixel that can be programmed to perform the task of an image sensor and the task of a solar cell to harvest energy. The basic idea is to design a pixel that can be configured to exploit its internal photodiode to perform two functions: image sensing and energy harvesting. As a proof of concept a 40 x 40 array of hybrid pixels has been designed and fabricated in a standard 0.5 microm CMOS process. Measurement results show that up to 39 microW of power can be harvested from the array under 130 Klux condition with an energy efficiency of 220 nJ /pixel /frame. The proposed image sensor is a current-mode image sensor which has several

  16. Color Doppler Imaging of Cardiac Catheters Using Vibrating Motors

    PubMed Central

    Reddy, Kalyan E.; Light, Edward D.; Rivera, Danny J.; Kisslo, Joseph A.; Smith, Stephen W.

    2010-01-01

    We attached a miniature motor rotating at 11,000 rpm onto the proximal end of cardiac electrophysiological (EP) catheters in order to produce vibrations at the tip which were then visualized by color Doppler on ultrasound scanners. We imaged the catheter tip within a vascular graft submerged in a water tank using the Volumetrics Medical Imaging 3D scanner, the Siemens Sonoline Antares 2D scanner, and the Philips ie33 3D ultrasound scanner with TEE probe. The vibrating catheter tip was visualized in each case though results varied with the color Doppler properties of the individual scanner. PMID:19514134

  17. Autopsy imaging for cardiac tamponade in a Thoroughbred foal

    PubMed Central

    YAMADA, Kazutaka; SATO, Fumio; HORIUCHI, Noriyuki; HIGUCHI, Tohru; KOBAYASHI, Yoshiyasu; SASAKI, Naoki; NAMBO, Yasuo

    2016-01-01

    ABSTRACT Autopsy imaging (Ai), postmortem imaging before necropsy, is used in human forensic medicine. Ai was performed using computed tomography (CT) for a 1-month-old Thoroughbred foal cadaver found in a pasture. CT revealed pericardial effusion, collapse of the aorta, bleeding in the lung lobe, gas in the ventricles and liver parenchyma, and distension of the digestive tract. Rupture in the left auricle was confirmed by necropsy; however, it was not depicted on CT. Therefore, Ai and conventional necropsy are considered to complement each other. The cause of death was determined to be traumatic cardiac tamponade. In conclusion, Ai is an additional option for determining cause of death. PMID:27703406

  18. Cardiac image modelling: Breadth and depth in heart disease.

    PubMed

    Suinesiaputra, Avan; McCulloch, Andrew D; Nash, Martyn P; Pontre, Beau; Young, Alistair A

    2016-10-01

    With the advent of large-scale imaging studies and big health data, and the corresponding growth in analytics, machine learning and computational image analysis methods, there are now exciting opportunities for deepening our understanding of the mechanisms and characteristics of heart disease. Two emerging fields are computational analysis of cardiac remodelling (shape and motion changes due to disease) and computational analysis of physiology and mechanics to estimate biophysical properties from non-invasive imaging. Many large cohort studies now underway around the world have been specifically designed based on non-invasive imaging technologies in order to gain new information about the development of heart disease from asymptomatic to clinical manifestations. These give an unprecedented breadth to the quantification of population variation and disease development. Also, for the individual patient, it is now possible to determine biophysical properties of myocardial tissue in health and disease by interpreting detailed imaging data using computational modelling. For these population and patient-specific computational modelling methods to develop further, we need open benchmarks for algorithm comparison and validation, open sharing of data and algorithms, and demonstration of clinical efficacy in patient management and care. The combination of population and patient-specific modelling will give new insights into the mechanisms of cardiac disease, in particular the development of heart failure, congenital heart disease, myocardial infarction, contractile dysfunction and diastolic dysfunction.

  19. Hybrid APD for single visible photon imaging

    NASA Astrophysics Data System (ADS)

    Smith, Bill; Passmore, Keith T.; Smith, Arlynn W.; Lundberg, Randy; Thomas, Nils I.; Bell, Nick; Lively, Chris; Sillmon, Roger; Benz, Rudolph G.; Karplus, Eric; Abraham, J. M.; Popenoe, Hugh W.; Farrell, Richard; Ferenc, Daniel

    2003-02-01

    A hybrid photodetector based on a Gen 3 photocathode and electron-bombarded silicon, non-pixilated, position sensitive, Avalanche Photo Diode (APD) is being developed. The device promises gains of over 106 and sub-millimeter spatial resolution. Signals read at the output of the device can be used to build up images, integrated over the time scales relevant to the process being studied. This integration as a post-process allows significant flexibility in investigation at very low light levels. A design and fabrication process is being developed that can be readily adapted for fast-turnaround proof-of-concept prototypes using a variety of solid state detectors. This process approach also facilitates the parallel development of high Quantum Efficiency (QE), low dark count III-V based photocathodes with a broad range of spectral response from UV to NIR. The Imaging Hybrid Avalanche Photo Diode (IHAPD) is targeted to bioluminescence, chemoluminescence and other low light level spectral imaging. A discussion of a reflection mode hybrid APD development is included as well.

  20. Bioluminescence imaging: a shining future for cardiac regeneration

    PubMed Central

    Roura, Santiago; Gálvez-Montón, Carolina; Bayes-Genis, Antoni

    2013-01-01

    Advances in bioanalytical techniques have become crucial for both basic research and medical practice. One example, bioluminescence imaging (BLI), is based on the application of natural reactants with light-emitting capabilities (photoproteins and luciferases) isolated from a widespread group of organisms. The main challenges in cardiac regeneration remain unresolved, but a vast number of studies have harnessed BLI with the discovery of aequorin and green fluorescent proteins. First described in the luminous hydromedusan Aequorea victoria in the early 1960s, bioluminescent proteins have greatly contributed to the design and initiation of ongoing cell-based clinical trials on cardiovascular diseases. In conjunction with advances in reporter gene technology, BLI provides valuable information about the location and functional status of regenerative cells implanted into numerous animal models of disease. The purpose of this review was to present the great potential of BLI, among other existing imaging modalities, to refine effectiveness and underlying mechanisms of cardiac cell therapy. We recount the first discovery of natural primary compounds with light-emitting capabilities, and follow their applications to bioanalysis. We also illustrate insights and perspectives on BLI to illuminate current efforts in cardiac regeneration, where the future is bright. PMID:23402217

  1. Hybrid imaging is the future of molecular imaging

    PubMed Central

    Hicks, RJ; Lau, EWF; Binns, DS

    2007-01-01

    Correlative imaging has long been used in clinical practice and particularly for the interpretation of nuclear medicine studies wherein detailed anatomical information is often lacking. Previously, side-by-side comparison or software co-registration techniques were applied but suffered from technical limitations related to the differing geometries of the imaging equipment, differences in the positioning of patients and displacement of mobile structures between studies. The development of the first hybrid PET and CT device struck a chord with the medical imaging community that is still ringing loudly throughout the world. So successful has been the concept of PET-CT that none of the major medical imaging manufacturers now offers stand-alone PET scanners. Following close behind this success, SPECT-CT devices have recently been adopted by the nuclear medicine community, already compelled by the benefits of hybrid imaging through their experience with PET-CT. Recent reports of adaptation of PET detectors to operate within the strong magnetic field of MRI scanners have generated further enthusiasm. Prototype PET-MRI devices are now in development. The complementary anatomical, functional and molecular information provided by these techniques can now be presented in an intuitive and aesthetically-pleasing format. This has made end-users more comfortable with the results of functional imaging techniques than when the same information is presented independently. Despite the primacy of anatomical imaging for locoregional disease definition, the molecular characterisation available from PET and SPECT offers unique complementary information for cancer evaluation. A new era of cancer imaging, when hybrid imaging will be the primary diagnostic tool, is approaching. PMID:21614291

  2. Reduced Graphene Oxide-GelMA Hybrid Hydrogels as Scaffolds for Cardiac Tissue Engineering.

    PubMed

    Shin, Su Ryon; Zihlmann, Claudio; Akbari, Mohsen; Assawes, Pribpandao; Cheung, Louis; Zhang, Kaizhen; Manoharan, Vijayan; Zhang, Yu Shrike; Yüksekkaya, Mehmet; Wan, Kai-Tak; Nikkhah, Mehdi; Dokmeci, Mehmet R; Tang, Xiaowu Shirley; Khademhosseini, Ali

    2016-07-01

    Biomaterials currently used in cardiac tissue engineering have certain limitations, such as lack of electrical conductivity and appropriate mechanical properties, which are two parameters playing a key role in regulating cardiac cell behavior. Here, the myocardial tissue constructs are engineered based on reduced graphene oxide (rGO)-incorporated gelatin methacryloyl (GelMA) hybrid hydrogels. The incorporation of rGO into the GelMA matrix significantly enhances the electrical conductivity and mechanical properties of the material. Moreover, cells cultured on composite rGO-GelMA scaffolds exhibit better biological activities such as cell viability, proliferation, and maturation compared to ones cultured on GelMA hydrogels. Cardiomyocytes show stronger contractility and faster spontaneous beating rate on rGO-GelMA hydrogel sheets compared to those on pristine GelMA hydrogels, as well as GO-GelMA hydrogel sheets with similar mechanical property and particle concentration. Our strategy of integrating rGO within a biocompatible hydrogel is expected to be broadly applicable for future biomaterial designs to improve tissue engineering outcomes. The engineered cardiac tissue constructs using rGO incorporated hybrid hydrogels can potentially provide high-fidelity tissue models for drug studies and the investigations of cardiac tissue development and/or disease processes in vitro. PMID:27254107

  3. Reduced Graphene Oxide-GelMA Hybrid Hydrogels as Scaffolds for Cardiac Tissue Engineering.

    PubMed

    Shin, Su Ryon; Zihlmann, Claudio; Akbari, Mohsen; Assawes, Pribpandao; Cheung, Louis; Zhang, Kaizhen; Manoharan, Vijayan; Zhang, Yu Shrike; Yüksekkaya, Mehmet; Wan, Kai-Tak; Nikkhah, Mehdi; Dokmeci, Mehmet R; Tang, Xiaowu Shirley; Khademhosseini, Ali

    2016-07-01

    Biomaterials currently used in cardiac tissue engineering have certain limitations, such as lack of electrical conductivity and appropriate mechanical properties, which are two parameters playing a key role in regulating cardiac cell behavior. Here, the myocardial tissue constructs are engineered based on reduced graphene oxide (rGO)-incorporated gelatin methacryloyl (GelMA) hybrid hydrogels. The incorporation of rGO into the GelMA matrix significantly enhances the electrical conductivity and mechanical properties of the material. Moreover, cells cultured on composite rGO-GelMA scaffolds exhibit better biological activities such as cell viability, proliferation, and maturation compared to ones cultured on GelMA hydrogels. Cardiomyocytes show stronger contractility and faster spontaneous beating rate on rGO-GelMA hydrogel sheets compared to those on pristine GelMA hydrogels, as well as GO-GelMA hydrogel sheets with similar mechanical property and particle concentration. Our strategy of integrating rGO within a biocompatible hydrogel is expected to be broadly applicable for future biomaterial designs to improve tissue engineering outcomes. The engineered cardiac tissue constructs using rGO incorporated hybrid hydrogels can potentially provide high-fidelity tissue models for drug studies and the investigations of cardiac tissue development and/or disease processes in vitro.

  4. High-performance web viewer for cardiac images

    NASA Astrophysics Data System (ADS)

    dos Santos, Marcelo; Furuie, Sergio S.

    2004-04-01

    With the advent of the digital devices for medical diagnosis the use of the regular films in radiology has decreased. Thus, the management and handling of medical images in digital format has become an important and critical task. In Cardiology, for example, the main difficulty is to display dynamic images with the appropriated color palette and frame rate used on acquisition process by Cath, Angio and Echo systems. In addition, other difficulty is handling large images in memory by any existing personal computer, including thin clients. In this work we present a web-based application that carries out these tasks with robustness and excellent performance, without burdening the server and network. This application provides near-diagnostic quality display of cardiac images stored as DICOM 3.0 files via a web browser and provides a set of resources that allows the viewing of still and dynamic images. It can access image files from the local disks, or network connection. Its features include: allows real-time playback, dynamic thumbnails image viewing during loading, access to patient database information, image processing tools, linear and angular measurements, on-screen annotations, image printing and exporting DICOM images to other image formats, and many others, all characterized by a pleasant user-friendly interface, inside a Web browser by means of a Java application. This approach offers some advantages over the most of medical images viewers, such as: facility of installation, integration with other systems by means of public and standardized interfaces, platform independence, efficient manipulation and display of medical images, all with high performance.

  5. Rapid Circular Tomography System Suitable For Cardiac Imaging

    NASA Astrophysics Data System (ADS)

    Kruger, R. A.; Sorensor, J. A.; Boye, J. R.; Conrad, J.; Ric, S. P. D.; Yih, B. C.; Liu, P.

    1985-06-01

    Tomographic DSA (digital subtraction angiography) can be used to improve the image quality that results from intravenous angiographic studies of relatively stationary arterial anatomy. While DSA removes much of the non-opacified anatomy, tomographic blurring reduces both the severity of patient motion artefacts and the confusion introduced by overlapping vascular anatomy. For this purpose a conventional longitudinal tomography device to which an image intensifier and television has been added can be used. However, such an apparatus is inadequate for cardiac imaging due to the slow speed of the tomographic motion. A tomographic system consisting of a rotating focal spot x-ray tube and an image intensifier, modified to allow electronic image scanning, is proposed. After this device is constructed it will be possible to acquire tomographic images of the beating heart in as little as .005-.010 seconds. When combined with image subtraction it is anticipated that the quality of intravenous coronary angiograms will be improved in much the same way that tomographic DSA improves image quality in many of the other arteries of the body.

  6. HOPIS: hybrid omnidirectional and perspective imaging system for mobile robots.

    PubMed

    Lin, Huei-Yung; Wang, Min-Liang

    2014-01-01

    In this paper, we present a framework for the hybrid omnidirectional and perspective robot vision system. Based on the hybrid imaging geometry, a generalized stereo approach is developed via the construction of virtual cameras. It is then used to rectify the hybrid image pair using the perspective projection model. The proposed method not only simplifies the computation of epipolar geometry for the hybrid imaging system, but also facilitates the stereo matching between the heterogeneous image formation. Experimental results for both the synthetic data and real scene images have demonstrated the feasibility of our approach. PMID:25192317

  7. HOPIS: hybrid omnidirectional and perspective imaging system for mobile robots.

    PubMed

    Lin, Huei-Yung; Wang, Min-Liang

    2014-09-04

    In this paper, we present a framework for the hybrid omnidirectional and perspective robot vision system. Based on the hybrid imaging geometry, a generalized stereo approach is developed via the construction of virtual cameras. It is then used to rectify the hybrid image pair using the perspective projection model. The proposed method not only simplifies the computation of epipolar geometry for the hybrid imaging system, but also facilitates the stereo matching between the heterogeneous image formation. Experimental results for both the synthetic data and real scene images have demonstrated the feasibility of our approach.

  8. Role of Hybrid Brain Imaging in Neuropsychiatric Disorders.

    PubMed

    Burhan, Amer M; Marlatt, Nicole M; Palaniyappan, Lena; Anazodo, Udunna C; Prato, Frank S

    2015-01-01

    This is a focused review of imaging literature to scope the utility of hybrid brain imaging in neuropsychiatric disorders. The review focuses on brain imaging modalities that utilize hybrid (fusion) techniques to characterize abnormal brain molecular signals in combination with structural and functional changes that have been observed in neuropsychiatric disorders. An overview of clinical hybrid brain imaging technologies for human use is followed by a selective review of the literature that conceptualizes the use of these technologies in understanding basic mechanisms of major neuropsychiatric disorders and their therapeutics. Neuronal network abnormalities are highlighted throughout this review to scope the utility of hybrid imaging as a potential biomarker for each disorder. PMID:26854172

  9. Role of Hybrid Brain Imaging in Neuropsychiatric Disorders

    PubMed Central

    Burhan, Amer M.; Marlatt, Nicole M.; Palaniyappan, Lena; Anazodo, Udunna C.; Prato, Frank S.

    2015-01-01

    This is a focused review of imaging literature to scope the utility of hybrid brain imaging in neuropsychiatric disorders. The review focuses on brain imaging modalities that utilize hybrid (fusion) techniques to characterize abnormal brain molecular signals in combination with structural and functional changes that have been observed in neuropsychiatric disorders. An overview of clinical hybrid brain imaging technologies for human use is followed by a selective review of the literature that conceptualizes the use of these technologies in understanding basic mechanisms of major neuropsychiatric disorders and their therapeutics. Neuronal network abnormalities are highlighted throughout this review to scope the utility of hybrid imaging as a potential biomarker for each disorder. PMID:26854172

  10. HOPIS: Hybrid Omnidirectional and Perspective Imaging System for Mobile Robots

    PubMed Central

    Lin, Huei-Yung.; Wang, Min-Liang.

    2014-01-01

    In this paper, we present a framework for the hybrid omnidirectional and perspective robot vision system. Based on the hybrid imaging geometry, a generalized stereo approach is developed via the construction of virtual cameras. It is then used to rectify the hybrid image pair using the perspective projection model. The proposed method not only simplifies the computation of epipolar geometry for the hybrid imaging system, but also facilitates the stereo matching between the heterogeneous image formation. Experimental results for both the synthetic data and real scene images have demonstrated the feasibility of our approach. PMID:25192317

  11. Towards robust specularity detection and inpainting in cardiac images

    NASA Astrophysics Data System (ADS)

    Alsaleh, Samar M.; Aviles, Angelica I.; Sobrevilla, Pilar; Casals, Alicia; Hahn, James

    2016-03-01

    Computer-assisted cardiac surgeries had major advances throughout the years and are gaining more popularity over conventional cardiac procedures as they offer many benefits to both patients and surgeons. One obvious advantage is that they enable surgeons to perform delicate tasks on the heart while it is still beating, avoiding the risks associated with cardiac arrest. Consequently, the surgical system needs to accurately compensate the physiological motion of the heart which is a very challenging task in medical robotics since there exist different sources of disturbances. One of which is the bright light reflections, known as specular highlights, that appear on the glossy surface of the heart and partially occlude the field of view. This work is focused on developing a robust approach that accurately detects and removes those highlights to reduce their disturbance to the surgeon and the motion compensation algorithm. As a first step, we exploit both color attributes and Fuzzy edge detector to identify specular regions in each acquired image frame. These two techniques together work as restricted thresholding and are able to accurately identify specular regions. Then, in order to eliminate the specularity artifact and give the surgeon a better perception of the heart, the second part of our solution is dedicated to correct the detected regions using inpainting to propagate and smooth the results. Our experimental results, which we carry out in realistic datasets, reveal how efficient and precise the proposed solution is, as well as demonstrate its robustness and real-time performance.

  12. Wide coverage by volume CT: benefits for cardiac imaging

    NASA Astrophysics Data System (ADS)

    Sablayrolles, Jean-Louis; Cesmeli, Erdogan; Mintandjian, Laura; Adda, Olivier; Dessalles-Martin, Diane

    2005-04-01

    With the development of new technologies, computed tomography (CT) is becoming a strong candidate for non-invasive imaging based tool for cardiac disease assessment. One of the challenges of cardiac CT is that a typical scan involves a breath hold period consisting of several heartbeats, about 20 sec with scanners having a longitudinal coverage of 2 cm, and causing the image quality (IQ) to be negatively impacted since beat to beat variation is high likely to occur without any medication, e.g. beta blockers. Because of this and the preference for shorter breath hold durations, a CT scanner with a wide coverage without the compromise in the spatial and temporal resolution of great clinical value. In this study, we aimed at determining the optimum scan duration and the delay relative to beginning of breath hold, to achieve high IQ. We acquired EKG data from 91 consecutive patients (77 M, 14 F; Age: 57 +/- 14) undergoing cardiac CT exams with contrast, performed on LightSpeed 16 and LightSpeed Pro16. As an IQ metric, we adopted the standard deviation of "beat-to-beat variation" (stdBBV) within a virtual scan period. Two radiologists evaluated images by assigning a score of 1 (worst) to 4 best). We validated stdBBV with the radiologist scores, which resulted in a population distribution of 9.5, 9.5, 31, and 50% for the score groups 1, 2, 3, and 4, respectively. Based on the scores, we defined a threshold for stdBBV and identified an optimum combination of virtual scan period and a delay. With the assumption that the relationship between the stdBBV and diagnosable scan IQ holds, our analysis suggested that the success rate can be improved to 100% with scan durations equal or less than 5 sec with a delay of 1 - 2 sec. We confirmed the suggested conclusion with LightSpeed VCT (GE Healthcare Technologies, Waukesha, WI), which has a wide longitudinal coverage, fine isotropic spatial resolution, and high temporal resolution, e.g. 40 mm coverage per rotation of 0.35 sec

  13. Dose optimization in cardiac x-ray imaging

    SciTech Connect

    Gislason-Lee, Amber J.; McMillan, Catherine; Cowen, Arnold R.; Davies, Andrew G.

    2013-09-15

    Purpose: The aim of this research was to optimize x-ray image quality to dose ratios in the cardiac catheterization laboratory. This study examined independently the effects of peak x-ray tube voltage (kVp), copper (Cu), and gadolinium (Gd) x-ray beam filtration on the image quality to radiation dose balance for adult patient sizes.Methods: Image sequences of polymethyl methacrylate (PMMA) phantoms representing two adult patient sizes were captured using a modern flat panel detector based x-ray imaging system. Tin and copper test details were used to simulate iodine-based contrast medium and stents/guide wires respectively, which are used in clinical procedures. Noise measurement for a flat field image and test detail contrast were used to calculate the contrast to noise ratio (CNR). Entrance surface dose (ESD) and effective dose measurements were obtained to calculate the figure of merit (FOM), CNR{sup 2}/dose. This FOM determined the dose efficiency of x-ray spectra investigated. Images were captured with 0.0, 0.1, 0.25, 0.4, and 0.9 mm Cu filtration and with a range of gadolinium oxysulphide (Gd{sub 2}O{sub 2}S) filtration.Results: Optimum x-ray spectra were the same for the tin and copper test details. Lower peak tube voltages were generally favored. For the 20 cm phantom, using 2 Lanex Fast Back Gd{sub 2}O{sub 2}S screens as x-ray filtration at 65 kVp provided the highest FOM considering ESD and effective dose. Considering ESD, this FOM was only marginally larger than that from using 0.4 mm Cu at 65 kVp. For the 30 cm phantom, using 0.25 mm copper filtration at 80 kVp was most optimal; considering effective dose the FOM was highest with no filtration at 65 kVp.Conclusions: These settings, adjusted for x-ray tube loading limits and clinically acceptable image quality, should provide a useful option for optimizing patient dose to image quality in cardiac x-ray imaging. The same optimal x-ray beam spectra were found for both the tin and copper details, suggesting

  14. InAsSb Hybrid Imager Evaluation

    NASA Astrophysics Data System (ADS)

    Rode, J. P.

    1980-05-01

    Current research on infrared hybrid focal planes is directed toward devices in which detection occurs in a p-n junction formed in an intrinsic narrow energy bandgap semiconductor, and signal processing is accomplished in a Si CCD multiplexer which is electrically interfaced to the detector array. A hybrid array such as this, where the detector format is a 32 x 32 matrix, has been fabricated. The active material is backside-illuminated InAsSb which has been planar processed and fully passivated. The cutoff wavelength is 4.0 μm at the operating temperature of 77K. The CCD is four phase with a two level polysilicon gate structure. The signal input is via direct injection with an option for dc suppression. Operation of the focal plane in a staring mode that uses dc suppression is discussed. Data derived from the video output is presented; this includes responsivity and detectivity. Off focal plane non-uniformity compensation is also discussed. Displays of thermal images utilizing processed data from the hybrid focal plane array will be shown.

  15. Dual-Phase Cardiac Diffusion Tensor Imaging with Strain Correction

    PubMed Central

    Stoeck, Christian T.; Kalinowska, Aleksandra; von Deuster, Constantin; Harmer, Jack; Chan, Rachel W.; Niemann, Markus; Manka, Robert; Atkinson, David; Sosnovik, David E.; Mekkaoui, Choukri; Kozerke, Sebastian

    2014-01-01

    Purpose In this work we present a dual-phase diffusion tensor imaging (DTI) technique that incorporates a correction scheme for the cardiac material strain, based on 3D myocardial tagging. Methods In vivo dual-phase cardiac DTI with a stimulated echo approach and 3D tagging was performed in 10 healthy volunteers. The time course of material strain was estimated from the tagging data and used to correct for strain effects in the diffusion weighted acquisition. Mean diffusivity, fractional anisotropy, helix, transverse and sheet angles were calculated and compared between systole and diastole, with and without strain correction. Data acquired at the systolic sweet spot, where the effects of strain are eliminated, served as a reference. Results The impact of strain correction on helix angle was small. However, large differences were observed in the transverse and sheet angle values, with and without strain correction. The standard deviation of systolic transverse angles was significantly reduced from 35.9±3.9° to 27.8°±3.5° (p<0.001) upon strain-correction indicating more coherent fiber tracks after correction. Myocyte aggregate structure was aligned more longitudinally in systole compared to diastole as reflected by an increased transmural range of helix angles (71.8°±3.9° systole vs. 55.6°±5.6°, p<0.001 diastole). While diastolic sheet angle histograms had dominant counts at high sheet angle values, systolic histograms showed lower sheet angle values indicating a reorientation of myocyte sheets during contraction. Conclusion An approach for dual-phase cardiac DTI with correction for material strain has been successfully implemented. This technique allows assessing dynamic changes in myofiber architecture between systole and diastole, and emphasizes the need for strain correction when sheet architecture in the heart is imaged with a stimulated echo approach. PMID:25191900

  16. Tough and Flexible CNT-Polymeric Hybrid Scaffolds for Engineering Cardiac Constructs

    PubMed Central

    Kharaziha, Mahshid; Ryon Shin, Su; Nikkhah, Mehdi; Nur Topkaya, Seda; Masoumi, Nafiseh; Annabi, Nasim; Dokmeci, Mehmet. R.

    2014-01-01

    In the past few years, a considerable amount of effort has been devoted toward the development of biomimetic scaffolds for cardiac tissue engineering. However, most of the previous scaffolds have been electrically insulating or lacked the structural and mechanical robustness to engineer cardiac tissue constructs with suitable electrophysiological functions. Here, we developed tough and flexible hybrid scaffolds with enhanced electrical properties composed of carbon nanotubes (CNTs) embedded aligned poly(glycerol sebacate):gelatin (PG) electrospun nanofibers. Incorporation of varying concentrations of CNTs from 0 to 1.5% within the PG nanofibrous scaffolds (CNT-PG scaffolds) notably enhanced fiber alignment and improved the electrical conductivity and toughness of the scaffolds while maintaining the viability, retention, alignment, and contractile activities of cardiomyocytes (CMs) seeded on the scaffolds. The resulting CNT-PG scaffolds resulted in stronger spontaneous and synchronous beating behavior (3.5-fold lower excitation threshold and 2.8-fold higher maximum capture rate) compared to those cultured on PG scaffold. Overall, our findings demonstrated that aligned CNT-PG scaffold exhibited superior mechanical properties with enhanced CM beating properties. It is envisioned that the proposed hybrid scaffolds can be useful for generating cardiac tissue constructs with improved organization and maturation. PMID:24927679

  17. Imaging system for cardiac planar imaging using a dedicated dual-head gamma camera

    SciTech Connect

    Majewski, Stanislaw; Umeno, Marc M.

    2011-09-13

    A cardiac imaging system employing dual gamma imaging heads co-registered with one another to provide two dynamic simultaneous views of the heart sector of a patient torso. A first gamma imaging head is positioned in a first orientation with respect to the heart sector and a second gamma imaging head is positioned in a second orientation with respect to the heart sector. An adjustment arrangement is capable of adjusting the distance between the separate imaging heads and the angle between the heads. With the angle between the imaging heads set to 180 degrees and operating in a range of 140-159 keV and at a rate of up to 500kHz, the imaging heads are co-registered to produce simultaneous dynamic recording of two stereotactic views of the heart. The use of co-registered imaging heads maximizes the uniformity of detection sensitivity of blood flow in and around the heart over the whole heart volume and minimizes radiation absorption effects. A normalization/image fusion technique is implemented pixel-by-corresponding pixel to increase signal for any cardiac region viewed in two images obtained from the two opposed detector heads for the same time bin. The imaging system is capable of producing enhanced first pass studies, bloodpool studies including planar, gated and non-gated EKG studies, planar EKG perfusion studies, and planar hot spot imaging.

  18. New developments in paediatric cardiac functional ultrasound imaging.

    PubMed

    de Korte, Chris L; Nillesen, Maartje M; Saris, Anne E C M; Lopata, Richard G P; Thijssen, Johan M; Kapusta, Livia

    2014-07-01

    Ultrasound imaging can be used to estimate the morphology as well as the motion and deformation of tissues. If the interrogated tissue is actively deforming, this deformation is directly related to its function and quantification of this deformation is normally referred as 'strain imaging'. Tissue can also be deformed by applying an internal or external force and the resulting, induced deformation is a function of the mechanical tissue characteristics. In combination with the load applied, these strain maps can be used to estimate or reconstruct the mechanical properties of tissue. This technique was named 'elastography' by Ophir et al. in 1991. Elastography can be used for atherosclerotic plaque characterisation, while the contractility of the heart or skeletal muscles can be assessed with strain imaging. Rather than using the conventional video format (DICOM) image information, radio frequency (RF)-based ultrasound methods enable estimation of the deformation at higher resolution and with higher precision than commercial methods using Doppler (tissue Doppler imaging) or video image data (2D speckle tracking methods). However, the improvement in accuracy is mainly achieved when measuring strain along the ultrasound beam direction, so it has to be considered a 1D technique. Recently, this method has been extended to multiple directions and precision further improved by using spatial compounding of data acquired at multiple beam steered angles. Using similar techniques, the blood velocity and flow can be determined. RF-based techniques are also beneficial for automated segmentation of the ventricular cavities. In this paper, new developments in different techniques of quantifying cardiac function by strain imaging, automated segmentation, and methods of performing blood flow imaging are reviewed and their application in paediatric cardiology is discussed. PMID:27277901

  19. Cardiac magnetic resonance imaging safety following percutaneous coronary intervention.

    PubMed

    Curtis, Jason W; Lesniak, Donna C; Wible, James H; Woodard, Pamela K

    2013-10-01

    In the first 8 weeks after percutaneous coronary intervention (PCI), possible negative interactions exist between the cardiac magnetic resonance (CMR) imaging environment and the weakly ferromagnetic material in coronary stents. There are circumstances when CMR would be indicated shortly following PCI, such as acute myocardial infarction (AMI). The purpose of this study is to demonstrate CMR safety shortly following stent PCI in AMI patients. We performed a retrospective analysis of safety data in AMI patients with recently placed coronary artery stents enrolled in a multi-center phase II trial for gadoversetamide. Patients underwent 1.5 T CMR within 16 days of PCI. Vital signs (blood pressure, heart rate, respiratory rate, and body temperature) and ECGs were taken pre-CMR, 1, 2, and 24 h post-CMR. Any major adverse cardiac event (MACE) or other serious adverse events in the first 24 h after MRI were recorded. There were 258 stents in 211 AMI patients. The mean delay to CMR following PCI was 6.5 ± 4 days, with 62 patients (29 %) receiving CMR within 3 days and 132 patients (63 %) within 1 week. Patients showed no significant vital sign changes following CMR. Ten patients (4.7 %) showed mild, transient ECG changes. Within the 24-h follow-up group, 4 patients (1.9 %) had moderate to severe events, including chest pain (1) and elevated cardiac enzymes (1), resolving in 24 h; heart failure (1) and ischemic stroke (1). There were no deaths. This study demonstrates fewer MACE in AMI patients undergoing 1.5 T CMR within 16 days of stent placement in comparison to post-stent event rate reported in the literature. This study adds to the CMR after stent PCI safety profile suggested by previous studies and is the largest and first study that uses multicenter data to assess stent safety following CMR examination.

  20. Cardiac biplane strain imaging: initial in vivo experience.

    PubMed

    Lopata, R G P; Nillesen, M M; Verrijp, C N; Singh, S K; Lammens, M M Y; van der Laak, J A W M; van Wetten, H B; Thijssen, J M; Kapusta, L; de Korte, C L

    2010-02-21

    In this study, first we propose a biplane strain imaging method using a commercial ultrasound system, yielding estimation of the strain in three orthogonal directions. Secondly, an animal model of a child's heart was introduced that is suitable to simulate congenital heart disease and was used to test the method in vivo. The proposed approach can serve as a framework to monitor the development of cardiac hypertrophy and fibrosis. A 2D strain estimation technique using radio frequency (RF) ultrasound data was applied. Biplane image acquisition was performed at a relatively low frame rate (<100 Hz) using a commercial platform with an RF interface. For testing the method in vivo, biplane image sequences of the heart were recorded during the cardiac cycle in four dogs with an aortic stenosis. Initial results reveal the feasibility of measuring large radial, circumferential and longitudinal cumulative strain (up to 70%) at a frame rate of 100 Hz. Mean radial strain curves of a manually segmented region-of-interest in the infero-lateral wall show excellent correlation between the measured strain curves acquired in two perpendicular planes. Furthermore, the results show the feasibility and reproducibility of assessing radial, circumferential and longitudinal strains simultaneously. In this preliminary study, three beagles developed an elevated pressure gradient over the aortic valve (Deltap: 100-200 mmHg) and myocardial hypertrophy. One dog did not develop any sign of hypertrophy (Deltap = 20 mmHg). Initial strain (rate) results showed that the maximum strain (rate) decreased with increasing valvular stenosis (-50%), which is in accordance with previous studies. Histological findings corroborated these results and showed an increase in fibrotic tissue for the hearts with larger pressure gradients (100, 200 mmHg), as well as lower strain and strain rate values.

  1. Cardiac biplane strain imaging: initial in vivo experience

    NASA Astrophysics Data System (ADS)

    Lopata, R. G. P.; Nillesen, M. M.; Verrijp, C. N.; Singh, S. K.; Lammens, M. M. Y.; van der Laak, J. A. W. M.; van Wetten, H. B.; Thijssen, J. M.; Kapusta, L.; de Korte, C. L.

    2010-02-01

    In this study, first we propose a biplane strain imaging method using a commercial ultrasound system, yielding estimation of the strain in three orthogonal directions. Secondly, an animal model of a child's heart was introduced that is suitable to simulate congenital heart disease and was used to test the method in vivo. The proposed approach can serve as a framework to monitor the development of cardiac hypertrophy and fibrosis. A 2D strain estimation technique using radio frequency (RF) ultrasound data was applied. Biplane image acquisition was performed at a relatively low frame rate (<100 Hz) using a commercial platform with an RF interface. For testing the method in vivo, biplane image sequences of the heart were recorded during the cardiac cycle in four dogs with an aortic stenosis. Initial results reveal the feasibility of measuring large radial, circumferential and longitudinal cumulative strain (up to 70%) at a frame rate of 100 Hz. Mean radial strain curves of a manually segmented region-of-interest in the infero-lateral wall show excellent correlation between the measured strain curves acquired in two perpendicular planes. Furthermore, the results show the feasibility and reproducibility of assessing radial, circumferential and longitudinal strains simultaneously. In this preliminary study, three beagles developed an elevated pressure gradient over the aortic valve (Δp: 100-200 mmHg) and myocardial hypertrophy. One dog did not develop any sign of hypertrophy (Δp = 20 mmHg). Initial strain (rate) results showed that the maximum strain (rate) decreased with increasing valvular stenosis (-50%), which is in accordance with previous studies. Histological findings corroborated these results and showed an increase in fibrotic tissue for the hearts with larger pressure gradients (100, 200 mmHg), as well as lower strain and strain rate values.

  2. Hybrid Image-Plane/Stereo Manipulation

    NASA Technical Reports Server (NTRS)

    Baumgartner, Eric; Robinson, Matthew

    2004-01-01

    Hybrid Image-Plane/Stereo (HIPS) manipulation is a method of processing image data, and of controlling a robotic manipulator arm in response to the data, that enables the manipulator arm to place an end-effector (an instrument or tool) precisely with respect to a target (see figure). Unlike other stereoscopic machine-vision-based methods of controlling robots, this method is robust in the face of calibration errors and changes in calibration during operation. In this method, a stereoscopic pair of cameras on the robot first acquires images of the manipulator at a set of predefined poses. The image data are processed to obtain image-plane coordinates of known visible features of the end-effector. Next, there is computed an initial calibration in the form of a mapping between (1) the image-plane coordinates and (2) the nominal three-dimensional coordinates of the noted end-effector features in a reference frame fixed to the main robot body at the base of the manipulator. The nominal three-dimensional coordinates are obtained by use of the nominal forward kinematics of the manipulator arm that is, calculated by use of the currently measured manipulator joint angles and previously measured lengths of manipulator arm segments under the assumption that the arm segments are rigid, that the arm lengths are constant, and that there is no backlash. It is understood from the outset that these nominal three-dimensional coordinates are likely to contain possibly significant calibration errors, but the effects of the errors are progressively reduced, as described next. As the end-effector is moved toward the target, the calibration is updated repeatedly by use of data from newly acquired images of the end-effector and of the corresponding nominal coordinates in the manipulator reference frame. By use of the updated calibration, the coordinates of the target are computed in manipulator-reference-frame coordinates and then used to the necessary manipulator joint angles to position

  3. MR-Based Cardiac and Respiratory Motion-Compensation Techniques for PET-MR Imaging.

    PubMed

    Munoz, Camila; Kolbitsch, Christoph; Reader, Andrew J; Marsden, Paul; Schaeffter, Tobias; Prieto, Claudia

    2016-04-01

    Cardiac and respiratory motion cause image quality degradation in PET imaging, affecting diagnostic accuracy of the images. Whole-body simultaneous PET-MR scanners allow for using motion information estimated from MR images to correct PET data and produce motion-compensated PET images. This article reviews methods that have been proposed to estimate motion from MR images and different techniques to include this information in PET reconstruction, in order to overcome the problem of cardiac and respiratory motion in PET-MR imaging. MR-based motion correction techniques significantly increase lesion detectability and contrast, and also improve accuracy of uptake values in PET images.

  4. Utility of Magnetic Resonance Imaging in Cardiac Venous Anatomic Variants

    SciTech Connect

    Eckart, Robert E. Leitch, W. Shad; Shry, Eric A.; Krasuski, Richard A.; Lane, Michael J.; Leclerc, Kenneth M.

    2003-06-15

    The incidence of persistent left superior venacava (PLSVC) is approximately 0.5% in the general population; however,the coexistent absence of the right SVC has a reported incidence in tertiary centers of 0.1%. The vast majority of reports are limited to pediatric cardiology. Likewise, sinus of Valsalva aneurysm is a rare congenital anomaly, with a reported incidence of 0.1-3.5% of all congenital heart defects. We present a 71-year-old patient undergoing preoperative evaluation for incidental finding of aortic root aneurysm,and found to have all three in coexistence. Suggestive findings were demonstrated on cardiac catheterization and definitive diagnosis was made by magnetic resonance imaging. The use of MRI for the diagnosis of asymptomatic adult congenital heart disease will be reviewed.

  5. A hybrid continuous-wave terahertz imaging system

    SciTech Connect

    Dolganova, Irina N. Zaytsev, Kirill I. Metelkina, Anna A.; Karasik, Valeriy E.; Yurchenko, Stanislav O.

    2015-11-15

    A hybrid (active-passive mode) terahertz (THz) imaging system and an algorithm for imaging synthesis are proposed to enhance the THz image quality. The concept of image contrast is used to compare active and passive THz imaging. Combining the measurement of the self-emitted radiation of the object with the back-scattered source radiation measurement, it becomes possible to use the THz image to retrieve maximum information about the object. The experimental results confirm the advantages of hybrid THz imaging systems, which can be generalized for a wide range of applications in the material sciences, chemical physics, bio-systems, etc.

  6. Combining simulated patients and simulators: pilot study of hybrid simulation in teaching cardiac auscultation.

    PubMed

    Friederichs, Hendrik; Weissenstein, Anne; Ligges, Sandra; Möller, David; Becker, Jan C; Marschall, Bernhard

    2014-12-01

    Auscultation torsos are widely used to teach position-dependent heart sounds and murmurs. To provide a more realistic teaching experience, both whole body auscultation mannequins and torsos have been used in clinical examination skills training at the Medical Faculty of the University of Muenster since the winter term of 2008-2009. This training has since been extended by simulated patients, which are normal, healthy subjects who have undergone attachment of the electronic components of the auscultation mannequins to their chests to mimic pathophysiological conditions ("hybrid models"). The acceptance of this new learning method was examined in the present pilot study. In total, 143 students in their second preclinical year who were participating in auscultation training were randomized into an intervention group (hybrid models) and a control group (auscultation mannequins). One hundred forty-two (99.3%) of these students completed a self-assessment Likert-scale questionnaire regarding different teaching approaches (where 1 = "very poor" to 100 = "very good"). The questionnaire focused on the "value of learning" of different teaching approaches. Direct comparison showed that students evaluated the hybrid models to be significantly more effective than the auscultation mannequins (median: 83 vs. 64, P < 0.001). The cardiac auscultation training was generally assessed positively (median: 88). Additionally, verbal feedback was obtained from simulated patients and tutors (trained students who had successfully passed the course a few semesters earlier). Personal feedback showed high satisfaction from student tutors and simulated patients. Hybrid simulators for teaching cardiac auscultation elucidated positive responses from students, tutors, and simulated patients.

  7. A multiresolution restoration method for cardiac SPECT imaging.

    PubMed

    Franquiz, J M; Shukla, S

    1998-12-01

    In this study we present a multiresolution based method for restoring cardiac SPECT projections. Original projections were decomposed into a set of sub-band frequency images by using analyzing functions localized in both the space and frequency domain. This representation allows a simple denoising and restoration procedure by discarding high-frequency channels and performing inversion only in low frequencies. The method was evaluated in bull's eye reconstructions of a realistic cardiac chest phantom with a custom-made liver insert and 99mTc liver-to-heart activity ratios (LHAR) of 0:1, 1.5:1, 2.5:1, and 3.5:1. The cardiac phantom in free air was used as the reference standard. Reconstructions were performed by filtered backprojection using (1) no correction; (2) restoration without attenuation correction; (3) attenuation correction without restoration; and (4) restoration and attenuation correction. The attenuation correction was carried out with the Chang's method for one iteration. Results were compared with those obtained using an optimized prereconstruction Metz filter. Quantitative analysis was performed by calculating the normalized chi-square measure and mean +/- s.d. of bull's eye counts. In reconstructions with high liver activity (LHAR > 2), attenuation correction without restoration severely distorted the polar maps due to the spill-over of liver activity into the inferior myocardial wall. Both restoration methods when combined with an attenuation correction compensated this artifact and yielded uniform polar maps similar to that of the standard reference. There was no visual or quantitative difference between the performance of Metz filtering and multiresolution restoration. However, the main advantage of the multiresolution method is that it states a more concise and straightforward approach to the restoration problem. Multiresolution based methods does not require information about the object image or optimization processes, such as in conventional

  8. How much image noise can be added in cardiac x-ray imaging without loss in perceived image quality?

    NASA Astrophysics Data System (ADS)

    Gislason-Lee, Amber J.; Kumcu, Asli; Kengyelics, Stephen M.; Rhodes, Laura A.; Davies, Andrew G.

    2015-03-01

    Dynamic X-ray imaging systems are used for interventional cardiac procedures to treat coronary heart disease. X-ray settings are controlled automatically by specially-designed X-ray dose control mechanisms whose role is to ensure an adequate level of image quality is maintained with an acceptable radiation dose to the patient. Current commonplace dose control designs quantify image quality by performing a simple technical measurement directly from the image. However, the utility of cardiac X-ray images is in their interpretation by a cardiologist during an interventional procedure, rather than in a technical measurement. With the long term goal of devising a clinically-relevant image quality metric for an intelligent dose control system, we aim to investigate the relationship of image noise with clinical professionals' perception of dynamic image sequences. Computer-generated noise was added, in incremental amounts, to angiograms of five different patients selected to represent the range of adult cardiac patient sizes. A two alternative forced choice staircase experiment was used to determine the amount of noise which can be added to a patient image sequences without changing image quality as perceived by clinical professionals. Twenty-five viewing sessions (five for each patient) were completed by thirteen observers. Results demonstrated scope to increase the noise of cardiac X-ray images by up to 21% +/- 8% before it is noticeable by clinical professionals. This indicates a potential for 21% radiation dose reduction since X-ray image noise and radiation dose are directly related; this would be beneficial to both patients and personnel.

  9. Evaluation of an adaptive filtering algorithm for CT cardiac imaging with EKG modulated tube current

    NASA Astrophysics Data System (ADS)

    Li, Jianying; Hsieh, Jiang; Mohr, Kelly; Okerlund, Darin

    2005-04-01

    We have developed an adaptive filtering algorithm for cardiac CT scans with EKG-modulated tube current to optimize resolution and noise for different cardiac phases and to provide safety net for cases where end-systole phase is used for coronary imaging. This algorithm has been evaluated using patient cardiac CT scans where lower tube currents are used for the systolic phases. In this paper, we present the evaluation results. The results demonstrated that with the use of the proposed algorithm, we could improve image quality for all cardiac phases, while providing greater noise and streak artifact reduction for systole phases where lower CT dose were used.

  10. Computational Chemical Imaging for Cardiovascular Pathology: Chemical Microscopic Imaging Accurately Determines Cardiac Transplant Rejection

    PubMed Central

    Tiwari, Saumya; Reddy, Vijaya B.; Bhargava, Rohit; Raman, Jaishankar

    2015-01-01

    Rejection is a common problem after cardiac transplants leading to significant number of adverse events and deaths, particularly in the first year of transplantation. The gold standard to identify rejection is endomyocardial biopsy. This technique is complex, cumbersome and requires a lot of expertise in the correct interpretation of stained biopsy sections. Traditional histopathology cannot be used actively or quickly during cardiac interventions or surgery. Our objective was to develop a stain-less approach using an emerging technology, Fourier transform infrared (FT-IR) spectroscopic imaging to identify different components of cardiac tissue by their chemical and molecular basis aided by computer recognition, rather than by visual examination using optical microscopy. We studied this technique in assessment of cardiac transplant rejection to evaluate efficacy in an example of complex cardiovascular pathology. We recorded data from human cardiac transplant patients’ biopsies, used a Bayesian classification protocol and developed a visualization scheme to observe chemical differences without the need of stains or human supervision. Using receiver operating characteristic curves, we observed probabilities of detection greater than 95% for four out of five histological classes at 10% probability of false alarm at the cellular level while correctly identifying samples with the hallmarks of the immune response in all cases. The efficacy of manual examination can be significantly increased by observing the inherent biochemical changes in tissues, which enables us to achieve greater diagnostic confidence in an automated, label-free manner. We developed a computational pathology system that gives high contrast images and seems superior to traditional staining procedures. This study is a prelude to the development of real time in situ imaging systems, which can assist interventionists and surgeons actively during procedures. PMID:25932912

  11. Dose optimization in pediatric cardiac x-ray imaging

    SciTech Connect

    Gislason, Amber J.; Davies, Andrew G.; Cowen, Arnold R.

    2010-10-15

    Purpose: The aim of this research was to explore x-ray beam parameters with intent to optimize pediatric x-ray settings in the cardiac catheterization laboratory. This study examined the effects of peak x-ray tube voltage (kVp) and of copper (Cu) x-ray beam filtration independently on the image quality to dose balance for pediatric patient sizes. The impact of antiscatter grid removal on the image quality to dose balance was also investigated. Methods: Image sequences of polymethyl methacrylate phantoms approximating chest sizes typical of pediatric patients were captured using a modern flat-panel receptor based x-ray imaging system. Tin was used to simulate iodine-based contrast medium used in clinical procedures. Measurements of tin detail contrast and flat field image noise provided the contrast to noise ratio. Entrance surface dose (ESD) and effective dose (E) measurements were obtained to calculate the figure of merit (FOM), CNR{sup 2}/dose, which evaluated the dose efficiency of the x-ray parameters investigated. The kVp, tube current (mA), and pulse duration were set manually by overriding the system's automatic dose control mechanisms. Images were captured with 0, 0.1, 0.25, 0.4, and 0.9 mm added Cu filtration, for 50, 55, 60, 65, and 70 kVp with the antiscatter grid in place, and then with it removed. Results: For a given phantom thickness, as the Cu filter thickness was increased, lower kVp was favored. Examining kVp alone, lower values were generally favored, more so for thinner phantoms. Considering ESD, the 8.5 cm phantom had the highest FOM at 50 kVp using 0.4 mm of Cu filtration. The 12 cm phantom had the highest FOM at 55 kVp using 0.9 mm Cu, and the 16 cm phantom had highest FOM at 55 kVp using 0.4 mm Cu. With regard to E, the 8.5 and 12 cm phantoms had the highest FOM at 50 kVp using 0.4 mm of Cu filtration, and the 16 cm phantom had the highest FOM at 50 kVp using 0.25 mm Cu. Antiscatter grid removal improved the FOM for a given set of x

  12. Constrain static target kinetic iterative image reconstruction for 4D cardiac CT imaging

    NASA Astrophysics Data System (ADS)

    Alessio, Adam M.; La Riviere, Patrick J.

    2011-03-01

    Iterative image reconstruction offers improved signal to noise properties for CT imaging. A primary challenge with iterative methods is the substantial computation time. This computation time is even more prohibitive in 4D imaging applications, such as cardiac gated or dynamic acquisition sequences. In this work, we propose only updating the time-varying elements of a 4D image sequence while constraining the static elements to be fixed or slowly varying in time. We test the method with simulations of 4D acquisitions based on measured cardiac patient data from a) a retrospective cardiac-gated CT acquisition and b) a dynamic perfusion CT acquisition. We target the kinetic elements with one of two methods: 1) position a circular ROI on the heart, assuming area outside ROI is essentially static throughout imaging time; and 2) select varying elements from the coefficient of variation image formed from fast analytic reconstruction of all time frames. Targeted kinetic elements are updated with each iteration, while static elements remain fixed at initial image values formed from the reconstruction of data from all time frames. Results confirm that the computation time is proportional to the number of targeted elements; our simulations suggest that <30% of elements need to be updated in each frame leading to >3 times reductions in reconstruction time. The images reconstructed with the proposed method have matched mean square error with full 4D reconstruction. The proposed method is amenable to most optimization algorithms and offers the potential for significant computation improvements, which could be traded off for more sophisticated system models or penalty terms.

  13. Machine vision image quality measurement in cardiac x-ray imaging

    NASA Astrophysics Data System (ADS)

    Kengyelics, Stephen M.; Gislason-Lee, Amber; Keeble, Claire; Magee, Derek; Davies, Andrew G.

    2015-03-01

    The purpose of this work is to report on a machine vision approach for the automated measurement of x-ray image contrast of coronary arteries filled with iodine contrast media during interventional cardiac procedures. A machine vision algorithm was developed that creates a binary mask of the principal vessels of the coronary artery tree by thresholding a standard deviation map of the direction image of the cardiac scene derived using a Frangi filter. Using the mask, average contrast is calculated by fitting a Gaussian model to the greyscale profile orthogonal to the vessel centre line at a number of points along the vessel. The algorithm was applied to sections of single image frames from 30 left and 30 right coronary artery image sequences from different patients. Manual measurements of average contrast were also performed on the same images. A Bland-Altman analysis indicates good agreement between the two methods with 95% confidence intervals -0.046 to +0.048 with a mean bias of 0.001. The machine vision algorithm has the potential of providing real-time context sensitive information so that radiographic imaging control parameters could be adjusted on the basis of clinically relevant image content.

  14. Cardiac sarcoidosis demonstrated by Tl-201 and Ga-67 SPECT imaging

    SciTech Connect

    Taki, J.; Nakajima, K.; Bunko, H.; Ohguchi, M.; Tonami, N.; Hisada, K. )

    1990-09-01

    Ga-67 and Tl-201 SPECT was performed to evaluate cardiac sarcoidosis in a 15-year-old boy. Tl-201 SPECT imaging showed decreased uptake in the inferior to lateral wall and Ga-67 accumulation in the area of decreased Tl-201 uptake. These findings suggested cardiac sarcoidosis, and cardiac biopsy confirmed this diagnosis. After corticosteroid therapy, myocardial uptake of Ga-67 disappeared and myocardial TI-201 uptake became more homogeneous.

  15. Giant coronary artery aneurysm mimicking a compressive cardiac tumor Imaging features and operative strategy.

    PubMed

    Grandmougin, Daniel; Croisille, Pierre; Robin, Christophe; Péoc'h, Michel; Barral, Xavier

    2005-01-01

    Giant atheromatous coronary aneurysms mimicking a cardiac tumor remain exceptional. We report the case of a patient who experienced a severe inferior myocardial infarction related to a giant thrombosed coronary aneurysm masquerading a cardiac tumor and compressing right cardiac cavities with mechanical detrimental consequences on tricuspid, mitral and aortic valvular competence. The contribution of imaging was essential to assess diagnosis, understand the physiopathogeny of myocardial and valvular consequences and plan the optimal surgical strategy. PMID:16168902

  16. Multimodal Imaging after Sudden Cardiac Arrest in an 18-Year-Old Athlete

    PubMed Central

    Rehman, Mobeen Ur; Atalay, Michael K.; Broderick, Ryan J.

    2015-01-01

    We report the case of a previously healthy 18-year-old male athlete who twice presented with sudden cardiac arrest. Our use of electrocardiography, echocardiography, cardiac magnetic resonance, coronary angiography, coronary computed tomographic angiography, and nuclear stress testing enabled the diagnoses of apical hypertrophic cardiomyopathy and anomalous origin of the right coronary artery. We discuss the patient's treatment and note the useful role of multiple cardiovascular imaging methods in cases of sudden cardiac arrest. PMID:26664308

  17. Automatic cable artifact removal for cardiac C-arm CT imaging

    NASA Astrophysics Data System (ADS)

    Haase, C.; Schäfer, D.; Kim, M.; Chen, S. J.; Carroll, J.; Eshuis, P.; Dössel, O.; Grass, M.

    2014-03-01

    Cardiac C-arm computed tomography (CT) imaging using interventional C-arm systems can be applied in various areas of interventional cardiology ranging from structural heart disease and electrophysiology interventions to valve procedures in hybrid operating rooms. In contrast to conventional CT systems, the reconstruction field of view (FOV) of C-arm systems is limited to a region of interest in cone-beam (along the patient axis) and fan-beam (in the transaxial plane) direction. Hence, highly X-ray opaque objects (e.g. cables from the interventional setup) outside the reconstruction field of view, yield streak artifacts in the reconstruction volume. To decrease the impact of these streaks a cable tracking approach on the 2D projection sequences with subsequent interpolation is applied. The proposed approach uses the fact that the projected position of objects outside the reconstruction volume depends strongly on the projection perspective. By tracking candidate points over multiple projections only objects outside the reconstruction volume are segmented in the projections. The method is quantitatively evaluated based on 30 simulated CT data sets. The 3D root mean square deviation to a reference image could be reduced for all cases by an average of 50 % (min 16 %, max 76 %). Image quality improvement is shown for clinical whole heart data sets acquired on an interventional C-arm system.

  18. Hybrid PET/MR imaging: physics and technical considerations.

    PubMed

    Shah, Shetal N; Huang, Steve S

    2015-08-01

    In just over a decade, hybrid imaging with FDG PET/CT has become a standard bearer in the management of cancer patients. An exquisitely sensitive whole-body imaging modality, it combines the ability to detect subtle biologic changes with FDG PET and the anatomic information offered by CT scans. With advances in MR technology and advent of novel targeted PET radiotracers, hybrid PET/MRI is an evolutionary technique that is poised to revolutionize hybrid imaging. It offers unparalleled spatial resolution and functional multi-parametric data combined with biologic information in the non-invasive detection and characterization of diseases, without the deleterious effects of ionizing radiation. This article reviews the basic principles of FDG PET and MR imaging, discusses the salient technical developments of hybrid PET/MR systems, and provides an introduction to FDG PET/MR image acquisition.

  19. Denoising human cardiac diffusion tensor magnetic resonance images using sparse representation combined with segmentation.

    PubMed

    Bao, L J; Zhu, Y M; Liu, W Y; Croisille, P; Pu, Z B; Robini, M; Magnin, I E

    2009-03-21

    Cardiac diffusion tensor magnetic resonance imaging (DT-MRI) is noise sensitive, and the noise can induce numerous systematic errors in subsequent parameter calculations. This paper proposes a sparse representation-based method for denoising cardiac DT-MRI images. The method first generates a dictionary of multiple bases according to the features of the observed image. A segmentation algorithm based on nonstationary degree detector is then introduced to make the selection of atoms in the dictionary adapted to the image's features. The denoising is achieved by gradually approximating the underlying image using the atoms selected from the generated dictionary. The results on both simulated image and real cardiac DT-MRI images from ex vivo human hearts show that the proposed denoising method performs better than conventional denoising techniques by preserving image contrast and fine structures. PMID:19218737

  20. Cardiac Motion Tracking Using CINE Harmonic Phase (HARP) Magnetic Resonance Imaging

    PubMed Central

    Osman, Nael F.; Kerwin, William S.; McVeigh, Elliot R.; Prince, Jerry L.

    2007-01-01

    This article introduces a new image processing technique for rapid analysis of tagged cardiac magnetic resonance image sequences. The method uses isolated spectral peaks in SPAMM-tagged magnetic resonance images, which contain information about cardiac motion. The inverse Fourier transform of a spectral peak is a complex image whose calculated angle is called a harmonic phase (HARP) image. It is shown how two HARP image sequences can be used to automatically and accurately track material points through time. A rapid, semiautomated procedure to calculate circumferential and radial Lagrangian strain from tracked points is described. This new computational approach permits rapid analysis and visualization of myocardial strain within 5-10 min after the scan is complete. Its performance is demonstrated on MR image sequences reflecting both normal and abnormal cardiac motion. Results from the new method are shown to compare very well with a previously validated tracking algorithm. PMID:10571926

  1. Current cardiac imaging techniques for detection of left ventricular mass

    PubMed Central

    2010-01-01

    Estimation of left ventricular (LV) mass has both prognostic and therapeutic value independent of traditional risk factors. Unfortunately, LV mass evaluation has been underestimated in clinical practice. Assessment of LV mass can be performed by a number of imaging modalities. Despite inherent limitations, conventional echocardiography has fundamentally been established as most widely used diagnostic tool. 3-dimensional echocardiography (3DE) is now feasible, fast and accurate for LV mass evaluation. 3DE is also superior to conventional echocardiography in terms of LV mass assessment, especially in patients with abnormal LV geometry. Cardiovascular magnetic resonance (CMR) and cardiovascular computed tomography (CCT) are currently performed for LV mass assessment and also do not depend on cardiac geometry and display 3-dimensional data, as well. Therefore, CMR is being increasingly employed and is at the present standard of reference in the clinical setting. Although each method demonstrates advantages over another, there are also disadvantages to receive attention. Diagnostic accuracy of methods will also be increased with the introduction of more advanced systems. It is also likely that in the coming years new and more accurate diagnostic tests will become available. In particular, CMR and CCT have been intersecting hot topic between cardiology and radiology clinics. Thus, good communication and collaboration between two specialties is required for selection of an appropriate test. PMID:20515461

  2. Spatiotemporal processing of gated cardiac SPECT images using deformable mesh modeling

    SciTech Connect

    Brankov, Jovan G.; Yang Yongyi; Wernick, Miles N.

    2005-09-15

    In this paper we present a spatiotemporal processing approach, based on deformable mesh modeling, for noise reduction in gated cardiac single-photon emission computed tomography images. Because of the partial volume effect (PVE), clinical cardiac-gated perfusion images exhibit a phenomenon known as brightening--the myocardium appears to become brighter as the heart wall thickens. Although brightening is an artifact, it serves as an important diagnostic feature for assessment of wall thickening in clinical practice. Our proposed processing algorithm aims to preserve this important diagnostic feature while reducing the noise level in the images. The proposed algorithm is based on the use of a deformable mesh for modeling the cardiac motion in a gated cardiac sequence, based on which the images are processed by smoothing along space-time trajectories of object points while taking into account the PVE. Our experiments demonstrate that the proposed algorithm can yield significantly more-accurate results than several existing methods.

  3. Reduction of blooming artifacts in cardiac CT images by blind deconvolution and anisotropic diffusion filtering

    NASA Astrophysics Data System (ADS)

    Castillo-Amor, Angélica M.; Navarro-Navia, Cristian A.; Cadena-Bonfanti, Alberto J.; Contreras-Ortiz, Sonia H.

    2015-12-01

    Even though CT is an imaging technique that offers high quality images, limitations on its spatial resolution cause blurring in small objects with high contrast. This phenomenon is known as blooming artifact and affects cardiac images with small calcifications and stents. This paper describes an approach to reduce the blooming artifact and improve resolution in cardiac images using blind deconvolution and anisotropic diffusion filtering. Deconvolution increases resolution but reduces signal-to-noise ratio, and the anisotropic diffusion filter counteracts this effect without affecting the edges in the image.

  4. Monitoring radiation use in cardiac fluoroscopy imaging procedures

    SciTech Connect

    Stevens, Nathaniel T.; Steiner, Stefan H.; Smith, Ian R.; MacKay, R. Jock

    2011-01-15

    Purpose: Timely identification of systematic changes in radiation delivery of an imaging system can lead to a reduction in risk for the patients involved. However, existing quality assurance programs involving the routine testing of equipment performance using phantoms are limited in their ability to effectively carry out this task. To address this issue, the authors propose the implementation of an ongoing monitoring process that utilizes procedural data to identify unexpected large or small radiation exposures for individual patients, as well as to detect persistent changes in the radiation output of imaging platforms. Methods: Data used in this study were obtained from records routinely collected during procedures performed in the cardiac catheterization imaging facility at St. Andrew's War Memorial Hospital, Brisbane, Australia, over the period January 2008-March 2010. A two stage monitoring process employing individual and exponentially weighted moving average (EWMA) control charts was developed and used to identify unexpectedly high or low radiation exposure levels for individual patients, as well as detect persistent changes in the radiation output delivered by the imaging systems. To increase sensitivity of the charts, we account for variation in dose area product (DAP) values due to other measured factors (patient weight, fluoroscopy time, and digital acquisition frame count) using multiple linear regression. Control charts are then constructed using the residual values from this linear regression. The proposed monitoring process was evaluated using simulation to model the performance of the process under known conditions. Results: Retrospective application of this technique to actual clinical data identified a number of cases in which the DAP result could be considered unexpected. Most of these, upon review, were attributed to data entry errors. The charts monitoring the overall system radiation output trends demonstrated changes in equipment performance

  5. Automated hybridization/imaging device for fluorescent multiplex DNA sequencing

    DOEpatents

    Weiss, Robert B.; Kimball, Alvin W.; Gesteland, Raymond F.; Ferguson, F. Mark; Dunn, Diane M.; Di Sera, Leonard J.; Cherry, Joshua L.

    1995-01-01

    A method is disclosed for automated multiplex sequencing of DNA with an integrated automated imaging hybridization chamber system. This system comprises an hybridization chamber device for mounting a membrane containing size-fractionated multiplex sequencing reaction products, apparatus for fluid delivery to the chamber device, imaging apparatus for light delivery to the membrane and image recording of fluorescence emanating from the membrane while in the chamber device, and programmable controller apparatus for controlling operation of the system. The multiplex reaction products are hybridized with a probe, then an enzyme (such as alkaline phosphatase) is bound to a binding moiety on the probe, and a fluorogenic substrate (such as a benzothiazole derivative) is introduced into the chamber device by the fluid delivery apparatus. The enzyme converts the fluorogenic substrate into a fluorescent product which, when illuminated in the chamber device with a beam of light from the imaging apparatus, excites fluorescence of the fluorescent product to produce a pattern of hybridization. The pattern of hybridization is imaged by a CCD camera component of the imaging apparatus to obtain a series of digital signals. These signals are converted by the controller apparatus into a string of nucleotides corresponding to the nucleotide sequence an automated sequence reader. The method and apparatus are also applicable to other membrane-based applications such as colony and plaque hybridization and Southern, Northern, and Western blots.

  6. Automated hybridization/imaging device for fluorescent multiplex DNA sequencing

    DOEpatents

    Weiss, R.B.; Kimball, A.W.; Gesteland, R.F.; Ferguson, F.M.; Dunn, D.M.; Di Sera, L.J.; Cherry, J.L.

    1995-11-28

    A method is disclosed for automated multiplex sequencing of DNA with an integrated automated imaging hybridization chamber system. This system comprises an hybridization chamber device for mounting a membrane containing size-fractionated multiplex sequencing reaction products, apparatus for fluid delivery to the chamber device, imaging apparatus for light delivery to the membrane and image recording of fluorescence emanating from the membrane while in the chamber device, and programmable controller apparatus for controlling operation of the system. The multiplex reaction products are hybridized with a probe, the enzyme (such as alkaline phosphatase) is bound to a binding moiety on the probe, and a fluorogenic substrate (such as a benzothiazole derivative) is introduced into the chamber device by the fluid delivery apparatus. The enzyme converts the fluorogenic substrate into a fluorescent product which, when illuminated in the chamber device with a beam of light from the imaging apparatus, excites fluorescence of the fluorescent product to produce a pattern of hybridization. The pattern of hybridization is imaged by a CCD camera component of the imaging apparatus to obtain a series of digital signals. These signals are converted by the controller apparatus into a string of nucleotides corresponding to the nucleotide sequence an automated sequence reader. The method and apparatus are also applicable to other membrane-based applications such as colony and plaque hybridization and Southern, Northern, and Western blots. 9 figs.

  7. An active contour framework based on the Hermite transform for shape segmentation of cardiac MR images

    NASA Astrophysics Data System (ADS)

    Barba-J, Leiner; Escalante-Ramírez, Boris

    2016-04-01

    Early detection of cardiac affections is fundamental to address a correct treatment that allows preserving the patient's life. Since heart disease is one of the main causes of death in most countries, analysis of cardiac images is of great value for cardiac assessment. Cardiac MR has become essential for heart evaluation. In this work we present a segmentation framework for shape analysis in cardiac magnetic resonance (MR) images. The method consists of an active contour model which is guided by the spectral coefficients obtained from the Hermite transform (HT) of the data. The HT is used as model to code image features of the analyzed images. Region and boundary based energies are coded using the zero and first order coefficients. An additional shape constraint based on an elliptical function is used for controlling the active contour deformations. The proposed framework is applied to the segmentation of the endocardial and epicardial boundaries of the left ventricle using MR images with short axis view. The segmentation is sequential for both regions: the endocardium is segmented followed by the epicardium. The algorithm is evaluated with several MR images at different phases of the cardiac cycle demonstrating the effectiveness of the proposed method. Several metrics are used for performance evaluation.

  8. Patient-Centered Imaging: Shared Decision Making for Cardiac Imaging Procedures with Exposure to Ionizing Radiation

    PubMed Central

    Einstein, Andrew J.; Berman, Daniel S.; Min, James K.; Hendel, Robert C.; Gerber, Thomas C.; Carr, J. Jeffrey; Cerqueira, Manuel D.; Cullom, S. James; DeKemp, Robert; Dickert, Neal; Dorbala, Sharmila; Garcia, Ernest V.; Gibbons, Raymond J.; Halliburton, Sandra S.; Hausleiter, Jörg; Heller, Gary V.; Jerome, Scott; Lesser, John R.; Fazel, Reza; Raff, Gilbert L.; Tilkemeier, Peter; Williams, Kim A.; Shaw, Leslee J.

    2014-01-01

    Objective To identify key components of a radiation accountability framework fostering patient-centered imaging and shared decision-making in cardiac imaging. Background An NIH-NHLBI/NCI-sponsored symposium was held in November 2012 to address these issues. Methods Symposium participants, working in three tracks, identified key components of a framework to target critical radiation safety issues for the patient, the laboratory, and the larger population of patients with known or suspected cardiovascular disease. Results Use of ionizing radiation during an imaging procedure should be disclosed to all patients by the ordering provider at the time of ordering, and reinforced by the performing provider team. An imaging protocol with effective dose ≤3mSv is considered very low risk, not warranting extensive discussion or written consent. However, a protocol effective dose <20mSv was proposed as a level requiring particular attention in terms of shared decision-making and either formal discussion or written informed consent. Laboratory reporting of radiation dosimetry is a critical component of creating a quality laboratory fostering a patient-centered environment with transparent procedural methodology. Efforts should be directed to avoiding testing involving radiation, in patients with inappropriate indications. Standardized reporting and diagnostic reference levels for computed tomography and nuclear cardiology are important for the goal of public reporting of laboratory radiation dose levels in conjunction with diagnostic performance. Conclusions The development of cardiac imaging technologies revolutionized cardiology practice by allowing routine, noninvasive assessment of myocardial perfusion and anatomy. It is now incumbent upon the imaging community to create an accountability framework to safely drive appropriate imaging utilization. PMID:24530677

  9. Improved image quality and computation reduction in 4-D reconstruction of cardiac-gated SPECT images.

    PubMed

    Narayanan, M V; King, M A; Wernick, M N; Byrne, C L; Soares, E J; Pretorius, P H

    2000-05-01

    Spatiotemporal reconstruction of cardiac-gated SPECT images permits us to obtain valuable information related to cardiac function. However, the task of reconstructing this four-dimensional (4-D) data set is computation intensive. Typically, these studies are reconstructed frame-by-frame: a nonoptimal approach because temporal correlations in the signal are not accounted for. In this work, we show that the compression and signal decorrelation properties of the Karhunen-Loève (KL) transform may be used to greatly simplify the spatiotemporal reconstruction problem. The gated projections are first KL transformed in the temporal direction. This results in a sequence of KL-transformed projection images for which the signal components are uncorrelated along the time axis. As a result, the 4-D reconstruction task is simplified to a series of three-dimensional (3-D) reconstructions in the KL domain. The reconstructed KL components are subsequently inverse KL transformed to obtain the entire spatiotemporal reconstruction set. Our simulation and clinical results indicate that KL processing provides image sequences that are less noisy than are conventional frame-by-frame reconstructions. Additionally, by discarding high-order KL components that are dominated by noise, we can achieve savings in computation time because fewer reconstructions are needed in comparison to conventional frame-by-frame reconstructions.

  10. Fast automatic delineation of cardiac volume of interest in MSCT images

    NASA Astrophysics Data System (ADS)

    Lorenz, Cristian; Lessick, Jonathan; Lavi, Guy; Bulow, Thomas; Renisch, Steffen

    2004-05-01

    Computed Tomography Angiography (CTA) is an emerging modality for assessing cardiac anatomy. The delineation of the cardiac volume of interest (VOI) is a pre-processing step for subsequent visualization or image processing. It serves the suppression of anatomic structures being not in the primary focus of the cardiac application, such as sternum, ribs, spinal column, descending aorta and pulmonary vasculature. These structures obliterate standard visualizations such as direct volume renderings or maximum intensity projections. In addition, outcome and performance of post-processing steps such as ventricle suppression, coronary artery segmentation or the detection of short and long axes of the heart can be improved. The structures being part of the cardiac VOI (coronary arteries and veins, myocardium, ventricles and atria) differ tremendously in appearance. In addition, there is no clear image feature associated with the contour (or better cut-surface) distinguishing between cardiac VOI and surrounding tissue making the automatic delineation of the cardiac VOI a difficult task. The presented approach locates in a first step chest wall and descending aorta in all image slices giving a rough estimate of the location of the heart. In a second step, a Fourier based active contour approach delineates slice-wise the border of the cardiac VOI. The algorithm has been evaluated on 41 multi-slice CT data-sets including cases with coronary stents and venous and arterial bypasses. The typical processing time amounts to 5-10s on a 1GHz P3 PC.

  11. Feasibility of using respiration-averaged MR images for attenuation correction of cardiac PET/MR imaging.

    PubMed

    Ai, Hua; Pan, Tinsu

    2015-01-01

    Cardiac imaging is a promising application for combined PET/MR imaging. However, current MR imaging protocols for whole-body attenuation correction can produce spatial mismatch between PET and MR-derived attenuation data owing to a disparity between the two modalities' imaging speeds. We assessed the feasibility of using a respiration-averaged MR (AMR) method for attenuation correction of cardiac PET data in PET/MR images. First, to demonstrate the feasibility of motion imaging with MR, we used a 3T MR system and a two-dimensional fast spoiled gradient-recalled echo (SPGR) sequence to obtain AMR images ofa moving phantom. Then, we used the same sequence to obtain AMR images of a patient's thorax under free-breathing conditions. MR images were converted into PET attenuation maps using a three-class tissue segmentation method with two sets of predetermined CT numbers, one calculated from the patient-specific (PS) CT images and the other from a reference group (RG) containing 54 patient CT datasets. The MR-derived attenuation images were then used for attenuation correction of the cardiac PET data, which were compared to the PET data corrected with average CT (ACT) images. In the myocardium, the voxel-by-voxel differences and the differences in mean slice activity between the AMR-corrected PET data and the ACT-corrected PET data were found to be small (less than 7%). The use of AMR-derived attenuation images in place of ACT images for attenuation correction did not affect the summed stress score. These results demonstrate the feasibility of using the proposed SPGR-based MR imaging protocol to obtain patient AMR images and using those images for cardiac PET attenuation correction. Additional studies with more clinical data are warranted to further evaluate the method. PMID:26218995

  12. Challenges of cardiac image analysis in large-scale population-based studies.

    PubMed

    Medrano-Gracia, Pau; Cowan, Brett R; Suinesiaputra, Avan; Young, Alistair A

    2015-03-01

    Large-scale population-based imaging studies of preclinical and clinical heart disease are becoming possible due to the advent of standardized robust non-invasive imaging methods and infrastructure for big data analysis. This gives an exciting opportunity to gain new information about the development and progression of heart disease across population groups. However, the large amount of image data and prohibitive time required for image analysis present challenges for obtaining useful derived data from the images. Automated analysis tools for cardiac image analysis are only now becoming available. This paper reviews the challenges and possible solutions to the analysis of big imaging data in population studies. We also highlight the potential of recent large epidemiological studies using cardiac imaging to discover new knowledge on heart health and well-being.

  13. Comparison of magnetic resonance imaging and echocardiography in determination of cardiac dimensions in normal subjects.

    PubMed

    Friedman, B J; Waters, J; Kwan, O L; DeMaria, A N

    1985-06-01

    No data exist regarding the ability of magnetic resonance imaging to assess cardiac size and performance in human beings. Therefore, measurements of cardiac dimensions by magnetic resonance imaging were compared with those obtained by two-dimensional echocardiography in 21 normal subjects. Magnetic resonance transverse cardiac sections were obtained during electrocardiographic gating using a spin echo pulse sequence. In normal subjects, magnetic resonance imaging yielded a range of values for cardiac dimensions having a similar standard deviation as that of two-dimensional echocardiography. Diastolic measurements of the aorta, left atrium, left ventricle and septum obtained by magnetic resonance imaging correlated well with those obtained by two-dimensional echocardiography (r = 0.82, 0.78, 0.81 and 0.75, respectively). The correlation coefficient of r = 0.35 observed for the posterior wall thickness was not surprising in view of the narrow range of normal values. Only a general correlation (r = 0.53) existed for the right ventricular diastolic dimension; this was probably related to the difficulty in obtaining representative measurements due to the complex geometry of this chamber. Failure of systolic dimension measurements by magnetic resonance imaging to correlate with those obtained by echocardiography is probably related to limitations of electrocardiographic gating, especially of determining the exact end-systolic frame. Although technically complex at present, magnetic resonance imaging does provide an additional noninvasive technique for measurement of cardiac size.

  14. Pictorial review: electron beam computed tomography and multislice spiral computed tomography for cardiac imaging.

    PubMed

    Lembcke, Alexander; Hein, Patrick A; Dohmen, Pascal M; Klessen, Christian; Wiese, Till H; Hoffmann, Udo; Hamm, Bernd; Enzweiler, Christian N H

    2006-03-01

    Electron beam computed tomography (EBCT) revolutionized cardiac imaging by combining a constant high temporal resolution with prospective ECG triggering. For years, EBCT was the primary technique for some non-invasive diagnostic cardiac procedures such as calcium scoring and non-invasive angiography of the coronary arteries. Multislice spiral computed tomography (MSCT) on the other hand significantly advanced cardiac imaging through high volume coverage, improved spatial resolution and retrospective ECG gating. This pictorial review will illustrate the basic differences between both modalities with special emphasis to their image quality. Several experimental and clinical examples demonstrate the strengths and limitations of both imaging modalities in an intraindividual comparison for a broad range of diagnostic applications such as coronary artery calcium scoring, coronary angiography including stent visualization as well as functional assessment of the cardiac ventricles and valves. In general, our examples indicate that EBCT suffers from a number of shortcomings such as limited spatial resolution and a low contrast-to-noise ratio. Thus, EBCT should now only be used in selected cases where a constant high temporal resolution is a crucial issue, such as dynamic (cine) imaging. Due to isotropic submillimeter spatial resolution and retrospective data selection MSCT seems to be the non-invasive method of choice for cardiac imaging in general, and for assessment of the coronary arteries in particular. However, technical developments are still needed to further improve the temporal resolution in MSCT and to reduce the substantial radiation exposure. PMID:16427236

  15. SU-E-P-10: Imaging in the Cardiac Catheterization Lab - Technologies and Clinical Applications

    SciTech Connect

    Fetterly, K

    2014-06-01

    Purpose: Diagnosis and treatment of cardiovascular disease in the cardiac catheterization laboratory is often aided by a multitude of imaging technologies. The purpose of this work is to highlight the contributions to patient care offered by the various imaging systems used during cardiovascular interventional procedures. Methods: Imaging technologies used in the cardiac catheterization lab were characterized by their fundamental technology and by the clinical applications for which they are used. Whether the modality is external to the patient, intravascular, or intracavity was specified. Specific clinical procedures for which multiple modalities are routinely used will be highlighted. Results: X-ray imaging modalities include fluoroscopy/angiography and angiography CT. Ultrasound imaging is performed with external, trans-esophageal echocardiography (TEE), and intravascular (IVUS) transducers. Intravascular infrared optical coherence tomography (IVOCT) is used to assess vessel endothelium. Relatively large (>0.5 mm) anatomical structures are imaged with x-ray and ultrasound. IVUS and IVOCT provide high resolution images of vessel walls. Cardiac CT and MRI images are used to plan complex cardiovascular interventions. Advanced applications are used to spatially and temporally merge images from different technologies. Diagnosis and treatment of coronary artery disease frequently utilizes angiography and intra-vascular imaging, and treatment of complex structural heart conditions routinely includes use of multiple imaging modalities. Conclusion: There are several imaging modalities which are routinely used in the cardiac catheterization laboratory to diagnose and treat both coronary artery and structural heart disease. Multiple modalities are frequently used to enhance the quality and safety of procedures. The cardiac catheterization laboratory includes many opportunities for medical physicists to contribute substantially toward advancing patient care.

  16. Hybrid subband image coding scheme using DWT, DPCM, and ADPCM

    NASA Astrophysics Data System (ADS)

    Oh, Kyung-Seak; Kim, Sung-Jin; Joo, Chang-Bok

    1998-07-01

    Subband image coding techniques have received considerable attention as a powerful source coding ones. These techniques provide good compression results, and also can be extended for progressive transmission and multiresolution analysis. In this paper, we propose a hybrid subband image coding scheme using DWT (discrete wavelet transform), DPCM (differential pulse code modulation), and ADPCM (adaptive DPCM). This scheme produces both simple, but significant, image compression and transmission coding.

  17. Automated segmentation of cardiac visceral fat in low-dose non-contrast chest CT images

    NASA Astrophysics Data System (ADS)

    Xie, Yiting; Liang, Mingzhu; Yankelevitz, David F.; Henschke, Claudia I.; Reeves, Anthony P.

    2015-03-01

    Cardiac visceral fat was segmented from low-dose non-contrast chest CT images using a fully automated method. Cardiac visceral fat is defined as the fatty tissues surrounding the heart region, enclosed by the lungs and posterior to the sternum. It is measured by constraining the heart region with an Anatomy Label Map that contains robust segmentations of the lungs and other major organs and estimating the fatty tissue within this region. The algorithm was evaluated on 124 low-dose and 223 standard-dose non-contrast chest CT scans from two public datasets. Based on visual inspection, 343 cases had good cardiac visceral fat segmentation. For quantitative evaluation, manual markings of cardiac visceral fat regions were made in 3 image slices for 45 low-dose scans and the Dice similarity coefficient (DSC) was computed. The automated algorithm achieved an average DSC of 0.93. Cardiac visceral fat volume (CVFV), heart region volume (HRV) and their ratio were computed for each case. The correlation between cardiac visceral fat measurement and coronary artery and aortic calcification was also evaluated. Results indicated the automated algorithm for measuring cardiac visceral fat volume may be an alternative method to the traditional manual assessment of thoracic region fat content in the assessment of cardiovascular disease risk.

  18. Carbon tube electrodes for electrocardiography-gated cardiac multimodality imaging in mice.

    PubMed

    Choquet, Philippe; Goetz, Christian; Aubertin, Gaelle; Hubele, Fabrice; Sannié, Sébastien; Constantinesco, André

    2011-01-01

    This report describes a simple design of noninvasive carbon tube electrodes that facilitates electrocardiography (ECG) in mice during cardiac multimodality preclinical imaging. Both forepaws and the left hindpaw, covered by conductive gel, of mice were placed into the openings of small carbon tubes. Cardiac ECG-gated single-photon emission CT, X-ray CT, and MRI were tested (n = 60) in 20 mice. For all applications, electrodes were used in a warmed multimodality imaging cell. A heart rate of 563 ± 48 bpm was recorded from anesthetized mice regardless of the imaging technique used, with acquisition times ranging from 1 to 2 h.

  19. Robust segmentation of 4D cardiac MRI-tagged images via spatio-temporal propagation

    NASA Astrophysics Data System (ADS)

    Qian, Zhen; Huang, Xiaolei; Metaxas, Dimitris N.; Axel, Leon

    2005-04-01

    In this paper we present a robust method for segmenting and tracking cardiac contours and tags in 4D cardiac MRI tagged images via spatio-temporal propagation. Our method is based on two main techniques: the Metamorphs Segmentation for robust boundary estimation, and the tunable Gabor filter bank for tagging lines enhancement, removal and myocardium tracking. We have developed a prototype system based on the integration of these two techniques, and achieved efficient, robust segmentation and tracking with minimal human interaction.

  20. Improved Subspace Estimation for Low-Rank Model-Based Accelerated Cardiac Imaging

    PubMed Central

    Hitchens, T. Kevin; Wu, Yijen L.; Ho, Chien; Liang, Zhi-Pei

    2014-01-01

    Sparse sampling methods have emerged as effective tools to accelerate cardiac magnetic resonance imaging (MRI). Low-rank model-based cardiac imaging uses a pre-determined temporal subspace for image reconstruction from highly under-sampled (k, t)-space data and has been demonstrated effective for high-speed cardiac MRI. The accuracy of the temporal subspace is a key factor in these methods, yet little work has been published on data acquisition strategies to improve subspace estimation. This paper investigates the use of non-Cartesian k-space trajectories to replace the Cartesian trajectories which are omnipresent but are highly sensitive to readout direction. We also propose “self-navigated” pulse sequences which collect both navigator data (for determining the temporal subspace) and imaging data after every RF pulse, allowing for even greater acceleration. We investigate subspace estimation strategies through analysis of phantom images and demonstrate in vivo cardiac imaging in rats and mice without the use of ECG or respiratory gating. The proposed methods achieved 3-D imaging of wall motion, first-pass myocardial perfusion, and late gadolinium enhancement in rats at 74 frames per second (fps), as well as 2-D imaging of wall motion in mice at 97 fps. PMID:24801352

  1. Development of a PET/Cerenkov-light hybrid imaging system

    SciTech Connect

    Yamamoto, Seiichi Hamamura, Fuka; Kato, Katsuhiko; Ogata, Yoshimune; Watabe, Tadashi; Ikeda, Hayato; Kanai, Yasukazu; Hatazawa, Jun; Watabe, Hiroshi

    2014-09-15

    Purpose: Cerenkov-light imaging is a new molecular imaging technology that detects visible photons from high-speed electrons using a high sensitivity optical camera. However, the merit of Cerenkov-light imaging remains unclear. If a PET/Cerenkov-light hybrid imaging system were developed, the merit of Cerenkov-light imaging would be clarified by directly comparing these two imaging modalities. Methods: The authors developed and tested a PET/Cerenkov-light hybrid imaging system that consists of a dual-head PET system, a reflection mirror located above the subject, and a high sensitivity charge coupled device (CCD) camera. The authors installed these systems inside a black box for imaging the Cerenkov-light. The dual-head PET system employed a 1.2 × 1.2 × 10 mm{sup 3} GSO arranged in a 33 × 33 matrix that was optically coupled to a position sensitive photomultiplier tube to form a GSO block detector. The authors arranged two GSO block detectors 10 cm apart and positioned the subject between them. The Cerenkov-light above the subject is reflected by the mirror and changes its direction to the side of the PET system and is imaged by the high sensitivity CCD camera. Results: The dual-head PET system had a spatial resolution of ∼1.2 mm FWHM and sensitivity of ∼0.31% at the center of the FOV. The Cerenkov-light imaging system's spatial resolution was ∼275μm for a {sup 22}Na point source. Using the combined PET/Cerenkov-light hybrid imaging system, the authors successfully obtained fused images from simultaneously acquired images. The image distributions are sometimes different due to the light transmission and absorption in the body of the subject in the Cerenkov-light images. In simultaneous imaging of rat, the authors found that {sup 18}F-FDG accumulation was observed mainly in the Harderian gland on the PET image, while the distribution of Cerenkov-light was observed in the eyes. Conclusions: The authors conclude that their developed PET/Cerenkov-light hybrid

  2. Effects of Radiation Exposure From Cardiac Imaging: How Good Are the Data?

    PubMed Central

    Einstein, Andrew J.

    2012-01-01

    Concerns about medical exposure to ionizing radiation have become heightened in recent years due to rapid growth in procedure volumes and the high radiation doses incurred from some procedures. This article summarizes the evidence base undergirding concerns about radiation exposure in cardiac imaging. After classifying radiation effects, explaining terminology used to quantify the radiation received by patients, and describing typical doses from cardiac imaging procedures, I address the major epidemiological studies having bearing on radiation effects at doses comparable to those received by patients undergoing cardiac imaging. These include studies of atomic bomb survivors, nuclear industry workers, and children exposed in utero to x-rays, all of which have evidenced increased cancer risks at low doses. Additional higher dose epidemiological studies of cohorts exposed to radiation in the context of medical treatment are described and found to be generally compatible with these cardiac-dose-level studies, albeit with exceptions. Using risk projection models developed by the US National Academies that incorporate these data and reflect several evidence-based assumptions, cancer risk from cardiac imaging can be estimated and compared to benefits from imaging. Several ongoing epidemiological studies will provide better understanding of radiation-associated cancer risks. PMID:22300689

  3. Hybrid segmentation framework for 3D medical image analysis

    NASA Astrophysics Data System (ADS)

    Chen, Ting; Metaxas, Dimitri N.

    2003-05-01

    Medical image segmentation is the process that defines the region of interest in the image volume. Classical segmentation methods such as region-based methods and boundary-based methods cannot make full use of the information provided by the image. In this paper we proposed a general hybrid framework for 3D medical image segmentation purposes. In our approach we combine the Gibbs Prior model, and the deformable model. First, Gibbs Prior models are applied onto each slice in a 3D medical image volume and the segmentation results are combined to a 3D binary masks of the object. Then we create a deformable mesh based on this 3D binary mask. The deformable model will be lead to the edge features in the volume with the help of image derived external forces. The deformable model segmentation result can be used to update the parameters for Gibbs Prior models. These methods will then work recursively to reach a global segmentation solution. The hybrid segmentation framework has been applied to images with the objective of lung, heart, colon, jaw, tumor, and brain. The experimental data includes MRI (T1, T2, PD), CT, X-ray, Ultra-Sound images. High quality results are achieved with relatively efficient time cost. We also did validation work using expert manual segmentation as the ground truth. The result shows that the hybrid segmentation may have further clinical use.

  4. Accelerating dual cardiac phase images using undersampled radial phase encoding trajectories.

    PubMed

    Letelier, Karis; Urbina, Jesus; Andía, Marcelo; Tejos, Cristián; Irarrazaval, Pablo; Prieto, Claudia; Uribe, Sergio

    2016-09-01

    A three-dimensional dual-cardiac-phase (3D-DCP) scan has been proposed to acquire two data sets of the whole heart and great vessels during the end-diastolic and end-systolic cardiac phases in a single free-breathing scan. This method has shown accurate assessment of cardiac anatomy and function but is limited by long acquisition times. This work proposes to accelerate the acquisition and reconstruction of 3D-DCP scans by exploiting redundant information of the outer k-space regions of both cardiac phases. This is achieved using a modified radial-phase-encoding trajectory and gridding reconstruction with uniform coil combination. The end-diastolic acquisition trajectory was angularly shifted with respect to the end-systolic phase. Initially, a fully-sampled 3D-DCP scan was acquired to determine the optimal percentage of the outer k-space data that can be combined between cardiac phases. Thereafter, prospectively undersampled data were reconstructed based on this percentage. As gold standard images, the undersampled data were also reconstructed using iterative SENSE. To validate the method, image quality assessments and a cardiac volume analysis were performed. The proposed method was tested in thirteen healthy volunteers (mean age, 30years). Prospectively undersampled data (R=4) reconstructed with 50% combination led high quality images. There were no significant differences in the image quality and in the cardiac volume analysis between our method and iterative SENSE. In addition, the proposed approach reduced the reconstruction time from 40min to 1min. In conclusion, the proposed method obtains 3D-DCP scans with an image quality comparable to those reconstructed with iterative SENSE, and within a clinically acceptable reconstruction time. PMID:27067473

  5. Cardiac Magnetic Resonance Imaging Findings in 20-year Survivors of Mediastinal Radiotherapy for Hodgkin's Disease

    SciTech Connect

    Machann, Wolfram; Beer, Meinrad; Breunig, Margret; Stoerk, Stefan; Angermann, Christiane; Seufert, Ines; Schwab, Franz; Koelbl, Oliver; Flentje, Michael; Vordermark, Dirk

    2011-03-15

    Purpose: The recognition of the true prevalence of cardiac toxicity after mediastinal radiotherapy requires very long follow-up and a precise diagnostic procedure. Cardiac magnetic resonance imaging (MRI) permits excellent quantification of cardiac function and identification of localized myocardial defects and has now been applied to a group of 20-year Hodgkin's disease survivors. Methods and materials: Of 143 patients treated with anterior mediastinal radiotherapy (cobalt-60, median prescribed dose 40 Gy) for Hodgkin's disease between 1978 and 1985, all 53 survivors were invited for cardiac MRI. Of those, 36 patients (68%) presented for MRI, and in 31 patients (58%) MRI could be performed 20-28 years (median, 24) after radiotherapy. The following sequences were acquired on a 1.5-T MRI: transversal T1-weighted TSE and T2-weighted half-fourier acquisition single-shot turbo-spin-echo sequences, a steady-state free precession (SSFP) cine sequence in the short heart axis and in the four-chamber view, SSFP perfusion sequences under rest and adenosine stress, and a SSFP inversion recovery sequence for late enhancement. The MRI findings were correlated with previously reconstructed doses to cardiac structures. Results: Clinical characteristics and reconstructed doses were not significantly different between survivors undergoing and not undergoing MRI. Pathologic findings were reduced left ventricular function (ejection fraction <55%) in 7 (23%) patients, hemodynamically relevant valvular dysfunction in 13 (42%), late myocardial enhancement in 9 (29%), and any perfusion deficit in 21 (68%). An association of regional pathologic changes and reconstructed dose to cardiac structures could not be established. Conclusions: In 20-year survivors of Hodgkin's disease, cardiac MRI detects pathologic findings in approximately 70% of patients. Cardiac MRI has a potential role in cardiac imaging of Hodgkin's disease patients after mediastinal radiotherapy.

  6. Optical-digital hybrid image search system in cloud environment

    NASA Astrophysics Data System (ADS)

    Ikeda, Kanami; Kodate, Kashiko; Watanabe, Eriko

    2016-09-01

    To improve the versatility and usability of optical correlators, we developed an optical-digital hybrid image search system consisting of digital servers and an optical correlator that can be used to perform image searches in the cloud environment via a web browser. This hybrid system employs a simple method to obtain correlation signals and has a distributed network design. The correlation signals are acquired by using an encoder timing signal generated by a rotating disk, and the distributed network design facilitates the replacement and combination of the digital correlation server and the optical correlator.

  7. Optical–digital hybrid image search system in cloud environment

    NASA Astrophysics Data System (ADS)

    Ikeda, Kanami; Kodate, Kashiko; Watanabe, Eriko

    2016-09-01

    To improve the versatility and usability of optical correlators, we developed an optical–digital hybrid image search system consisting of digital servers and an optical correlator that can be used to perform image searches in the cloud environment via a web browser. This hybrid system employs a simple method to obtain correlation signals and has a distributed network design. The correlation signals are acquired by using an encoder timing signal generated by a rotating disk, and the distributed network design facilitates the replacement and combination of the digital correlation server and the optical correlator.

  8. Usefulness of Cardiac Sympathetic Nerve Imaging Using (123)Iodine-Metaiodobenzylguanidine Scintigraphy for Predicting Sudden Cardiac Death in Patients With Heart Failure.

    PubMed

    Kasama, Shu; Toyama, Takuji; Kurabayashi, Masahiko

    2016-01-01

    The autonomic nervous system plays an important role in the human heart. Activation of the cardiac sympathetic nervous system is a cardinal pathophysiological abnormality associated with the failing human heart. Myocardial imaging using (123)I-metaiodobenzylguanidine (MIBG), an analog of norepinephrine, can be used to investigate the activity of norepinephrine, the predominant neurotransmitter of the sympathetic nervous system. Many clinical trials have demonstrated that (123)I-MIBG scintigraphic parameters predict cardiac adverse events, especially sudden cardiac death, in patients with heart failure. In this review, we summarize results from published studies that have focused on the use of cardiac sympathetic nerve imaging using (123)I-MIBG scintigraphy for risk stratification of sudden cardiac death in patients with heart failure.

  9. Engineered hybrid cardiac patches with multifunctional electronics for online monitoring and regulation of tissue function

    NASA Astrophysics Data System (ADS)

    Feiner, Ron; Engel, Leeya; Fleischer, Sharon; Malki, Maayan; Gal, Idan; Shapira, Assaf; Shacham-Diamand, Yosi; Dvir, Tal

    2016-06-01

    In cardiac tissue engineering approaches to treat myocardial infarction, cardiac cells are seeded within three-dimensional porous scaffolds to create functional cardiac patches. However, current cardiac patches do not allow for online monitoring and reporting of engineered-tissue performance, and do not interfere to deliver signals for patch activation or to enable its integration with the host. Here, we report an engineered cardiac patch that integrates cardiac cells with flexible, freestanding electronics and a 3D nanocomposite scaffold. The patch exhibited robust electronic properties, enabling the recording of cellular electrical activities and the on-demand provision of electrical stimulation for synchronizing cell contraction. We also show that electroactive polymers containing biological factors can be deposited on designated electrodes to release drugs in the patch microenvironment on demand. We expect that the integration of complex electronics within cardiac patches will eventually provide therapeutic control and regulation of cardiac function.

  10. Engineered hybrid cardiac patches with multifunctional electronics for online monitoring and regulation of tissue function

    PubMed Central

    Feiner, Ron; Engel, Leeya; Fleischer, Sharon; Malki, Maayan; Gal, Idan; Shapira, Assaf; Shacham-Diamand, Yosi; Dvir, Tal

    2016-01-01

    In cardiac tissue engineering approaches to treat myocardial infarction, cardiac cells are seeded within three-dimensional porous scaffolds to create functional cardiac patches. However, current cardiac patches do not allow for online monitoring and reporting of engineered-tissue performance, and do not interfere to deliver signals for patch activation or to enable its integration with the host. Here, we report an engineered cardiac patch that integrates cardiac cells with flexible, free-standing electronics and a 3D nanocomposite scaffold. The patch exhibited robust electronic properties, enabling the recording of cellular electrical activities and the on-demand provision of electrical stimulation for synchronizing cell contraction. We also show that electroactive polymers containing biological factors can be deposited on designated electrodes to release drugs in the patch microenvironment on-demand. We expect that the integration of complex electronics within cardiac patches will eventually provide therapeutic control and regulation of cardiac function. PMID:26974408

  11. Hybrid Pixel Detectors for gamma/X-ray imaging

    NASA Astrophysics Data System (ADS)

    Hatzistratis, D.; Theodoratos, G.; Zografos, V.; Kazas, I.; Loukas, D.; Lambropoulos, C. P.

    2015-09-01

    Hybrid pixel detectors are made by direct converting high-Z semi-insulating single crystalline material coupled to complementary-metal-oxide semiconductor (CMOS) readout electronics. They are attractive because direct conversion exterminates all the problems of spatial localization related to light diffusion, energy resolution, is far superior from the combination of scintillation crystals and photomultipliers and lithography can be used to pattern electrodes with very fine pitch. We are developing 2-D pixel CMOS ASICs, connect them to pixilated CdTe crystals with the flip chip and bump bonding method and characterize the hybrids. We have designed a series of circuits, whose latest member consists of a 50×25 pixel array with 400um pitch and an embedded controller. In every pixel a full spectroscopic channel with time tagging information has been implemented. The detectors are targeting Compton scatter imaging and they can be used for coded aperture imaging too. Hybridization using CMOS can overcome the limit put on pixel circuit complexity by the use of thin film transistors (TFT) in large flat panels. Hybrid active pixel sensors are used in dental imaging and other applications (e.g. industrial CT etc.). Thus X-ray imaging can benefit from the work done on dynamic range enhancement methods developed initially for visible and infrared CMOS pixel sensors. A 2-D CMOS ASIC with 100um pixel pitch to demonstrate the feasibility of such methods in the context of X-ray imaging has been designed.

  12. Virtual and augmented medical imaging environments: enabling technology for minimally invasive cardiac interventional guidance.

    PubMed

    Linte, Cristian A; White, James; Eagleson, Roy; Guiraudon, Gérard M; Peters, Terry M

    2010-01-01

    Virtual and augmented reality environments have been adopted in medicine as a means to enhance the clinician's view of the anatomy and facilitate the performance of minimally invasive procedures. Their value is truly appreciated during interventions where the surgeon cannot directly visualize the targets to be treated, such as during cardiac procedures performed on the beating heart. These environments must accurately represent the real surgical field and require seamless integration of pre- and intra-operative imaging, surgical tracking, and visualization technology in a common framework centered around the patient. This review begins with an overview of minimally invasive cardiac interventions, describes the architecture of a typical surgical guidance platform including imaging, tracking, registration and visualization, highlights both clinical and engineering accuracy limitations in cardiac image guidance, and discusses the translation of the work from the laboratory into the operating room together with typically encountered challenges. PMID:22275200

  13. Noninvasive detection of human cardiac transplant rejection with indium-111 antimyosin (Fab) imaging

    SciTech Connect

    Frist, W.; Yasuda, T.; Segall, G.; Khaw, B.A.; Strauss, H.W.; Gold, H.; Stinson, E.; Oyer, P.; Baldwin, J.; Billingham, M.

    1987-11-01

    Diagnosis of rejection after cardiac transplantation is currently made by right ventricular endomyocardial biopsy. To evaluate antimyosin imaging as a noninvasive means of detecting human cardiac rejection, the Fab fragment of murine monoclonal antimyosin antibodies was labeled with indium-111 and given intravenously to 18 patients (age 45 +/- 12 years) in 20 studies 7 days to 9 years after transplantation. Endomyocardial biopsy specimens were obtained at the time of each imaging study. Eight patients had positive scans confirmed by biopsy as rejection, and eight patients had negative scans and no evidence of rejection on biopsy. Discordance was observed in four studies, two with positive scans and no rejection on biopsy and two with negative scans and positive biopsy. The sensitivity, specificity, and overall accuracy of the technique were each 80%. Imaging with radiolabeled antimyosin antibody Fab fragments may be of value in the noninvasive identification of rejection in the cardiac transplant recipient.

  14. Tag removal in cardiac tagged MRI images using coupled dictionary learning.

    PubMed

    Makram, Abram W; Rushdi, Muhammad A; Khalifa, Ayman M; El-Wakad, Mohamed T

    2015-01-01

    Tagged Magnetic Resonance Imaging (tMRI) is considered to be the gold standard for quantitative assessment of the cardiac local functions. However, the tagging patterns and low myocardium-to-blood-pool contrast of tagged images bring great challenges to cardiac image processing and analysis tasks such as myocardium segmentation and tracking. Hence, there has been growing interest in techniques for removing tagging lines. In this work, a method for removing tagging patterns in tagged MR images using a coupled dictionary learning (CDL) model is proposed. In this model, identical sparse representations are assumed for image patches in the tagged MRI and corresponding cine MRI image spaces. First, we learn a dictionary for the tagged MRI image space. Then, we compute a dictionary for the cine MRI image space so that corresponding tagged and cine patches have the same sparse codes in terms of their respective dictionaries. Finally, in order to produce the de-tagged (cine version) of a test tagged image, the sparse codes of the tagged patches and the trained cine dictionary are used together to construct the de-tagged patches. We have tested this tag removal method on a dataset of tagged cardiac MR images. Our experimental results compared favorably with a recently proposed tag removal method that removes tags in the frequency domain using an optimal band-stop filter of harmonic peaks.

  15. Unsupervised segmentation of cardiac PET transmission images for automatic heart volume extraction.

    PubMed

    Juslin, Anu; Tohka, Jussi

    2006-01-01

    In this study, we propose an automatic method to extract the heart volume from the cardiac positron emission tomography (PET) transmission images. The method combines the automatic 3D segmentation of the transmission image using Markov random fields (MRFs) to surface extraction using deformable models. Deformable models were automatically initialized using the MRFs segmentation result. The extraction of the heart region is needed e.g. in independent component analysis (ICA). The volume of the heart can be used to mask the emission image corresponding to the transmission image, so that only the cardiac region is used for the analysis. The masking restricts the number of independent components and reduces the computation time. In addition, the MRF segmentation result could be used for attenuation correction. The method was tested with 25 patient images. The MRF segmentation results were of good quality in all cases and we were able to extract the heart volume from all the images. PMID:17946020

  16. Hybrid micro-/nanogels for optical sensing and intracellular imaging

    PubMed Central

    Wu, Weitai; Zhou, Shuiqin

    2010-01-01

    Hybrid micro-/nanogels are playing an increasing important part in a diverse range of applications, due to their tunable dimensions, large surface area, stable interior network structure, and a very short response time. We review recent advances and challenges in the developments of hybrid micro-/nanogels toward applications for optical sensing of pH, temperature, glucose, ions, and other species as well as for intracellular imaging. Due to their unique advantages, hybrid micro-/nanogels as optical probes are attracting substantial interests for continuous monitoring of chemical parameters in complex samples such as blood and bioreactor fluids, in chemical research and industry, and in food quality control. In particular, their intracellular probing ability enables the monitoring of the biochemistry and biophysics of live cells over time and space, thus contributing to the explanation of intricate biological processes and the development of novel diagnoses. Unlike most other probes, hybrid micro-/nanogels could also combine other multiple functions into a single probe. The rational design of hybrid micro-/nanogels will not only improve the probing applications as desirable, but also implement their applications in new arenas. With ongoing rapid advances in bionanotechnology, the well-designed hybrid micro-/nanogel probes will be able to provide simultaneous sensing, imaging diagnosis, and therapy toward clinical applications. PMID:22110866

  17. Imaging near metal with a MAVRIC-SEMAC hybrid.

    PubMed

    Koch, K M; Brau, A C; Chen, W; Gold, G E; Hargreaves, B A; Koff, M; McKinnon, G C; Potter, H G; King, K F

    2011-01-01

    The recently developed multi-acquisition with variable resonance image combination (MAVRIC) and slice-encoding metal artifact correction (SEMAC) techniques can significantly reduce image artifacts commonly encountered near embedded metal hardware. These artifact reductions are enabled by applying alternative spectral and spatial-encoding schemes to conventional spin-echo imaging techniques. Here, the MAVRIC and SEMAC concepts are connected and discussed. The development of a hybrid technique that utilizes strengths of both methods is then introduced. The presented technique is shown capable of producing minimal artifact, high-resolution images near total joint replacements in a clinical setting.

  18. Fully 4D motion-compensated reconstruction of cardiac SPECT images

    NASA Astrophysics Data System (ADS)

    Gravier, Erwan; Yang, Yongyi; King, Michael A.; Jin, Mingwu

    2006-09-01

    In this paper, we investigate the benefits of a spatiotemporal approach for reconstruction of image sequences. In the proposed approach, we introduce a temporal prior in the form of motion compensation to account for the statistical correlations among the frames in a sequence, and reconstruct all the frames collectively as a single function of space and time. The reconstruction algorithm is derived based on the maximum a posteriori estimate, for which the one-step late expectation-maximization algorithm is used. We demonstrated the method in our experiments using simulated single photon emission computed tomography (SPECT) cardiac perfusion images. The four-dimensional (4D) gated mathematical cardiac-torso phantom was used for simulation of gated SPECT perfusion imaging with Tc-99m-sestamibi. In addition to bias-variance analysis and time activity curves, we also used a channelized Hotelling observer to evaluate the detectability of perfusion defects in the reconstructed images. Our experimental results demonstrated that the incorporation of temporal regularization into image reconstruction could significantly improve the accuracy of cardiac images without causing any significant cross-frame blurring that may arise from the cardiac motion. This could lead to not only improved detection of perfusion defects, but also improved reconstruction of the heart wall which is important for functional assessment of the myocardium. This work was supported in part by the National Institutes of Health under grant no HL65425.

  19. A Quadricuspid Aortic Valve as Seen by Cardiac Magnetic Resonance Imaging.

    PubMed

    Jones, James; Liotta, Robert; Hood, Maureen; Bustamante, Alexander

    2016-09-01

    We report a case of a 35-year-old active duty male with a rare quadricuspid aortic valve identified via transthoracic echocardiography following the detection of an incidental grade I/VI diastolic murmur. Further characterization of the anatomical findings and aortic valve flow dynamics were evaluated with cardiac magnetic resonance imaging. Accurate assessment of the various valve morphologies is essential, as it guides surgical treatment options to correct the defect. Our case highlights the complimentary role of cardiac magnetic resonance imaging in defining the anatomy and functional consequences of a quadricuspid aortic valve. PMID:27612379

  20. Volume coil based on hybridized resonators for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Jouvaud, C.; Abdeddaim, R.; Larrat, B.; de Rosny, J.

    2016-01-01

    We present an electromagnetic device based on hybridization of four half-wavelength dipoles which increases the uniformity and the strength of the radio-frequency (RF) field of a Magnetic Resonant Imaging (MRI) apparatus. Numerical results show that this Hybridized Coil (HC) excited with a classical loop coil takes advantage of the magnetic hybrid modes. The distribution of the RF magnetic field is experimentally confirmed on a 7-T MRI with a gelatin phantom. Finally, the HC is validated in vivo by imaging the head of an anesthetized rat. We measure an overall increase of the signal to noise ratio with up to 2.4 fold increase in regions of interest far from the active loop coil.

  1. Positron emission tomographic imaging of cardiac sympathetic innervation and function

    SciTech Connect

    Goldstein, D.S.; Chang, P.C.; Eisenhofer, G.; Miletich, R.; Finn, R.; Bacher, J.; Kirk, K.L.; Bacharach, S.; Kopin, I.J. )

    1990-05-01

    Sites of uptake, storage, and metabolism of ({sup 18}F)fluorodopamine and excretion of ({sup 18}F)fluorodopamine and its metabolites were visualized using positron emission tomographic (PET) scanning after intravenous injection of the tracer into anesthetized dogs. Radioactivity was concentrated in the renal pelvis, heart, liver, spleen, salivary glands, and gall bladder. Uptake of 18F by the heart resulted in striking delineation of the left ventricular myocardium. Pretreatment with desipramine markedly decreased cardiac positron emission, consistent with dependence of the heart on neuronal uptake (uptake-1) for removal of circulating catecholamines. In reserpinized animals, cardiac positron emission was absent within 30 minutes after injection of ({sup 18}F)-6-fluorodopamine, demonstrating that the emission in untreated animals was from radioactive labeling of the sympathetic storage vesicles. Decreased positron emission from denervated salivary glands confirmed that the tracer was concentrated in sympathetic neurons. Radioactivity in the gall bladder and urinary system depicted the hepatic and renal excretion of the tracer and its metabolites. Administration of tyramine or nitroprusside increased and ganglionic blockade with trimethaphan decreased the rate of loss of myocardial radioactivity. The results show that PET scanning after administration of ({sup 18}F)fluorodopamine can be used to visualize sites of sympathetic innervation, follow the metabolism and renal and hepatic excretion of catecholamines, and examine cardiac sympathetic function.

  2. Image reconstruction for hybrid true-color micro-CT.

    PubMed

    Xu, Qiong; Yu, Hengyong; Bennett, James; He, Peng; Zainon, Rafidah; Doesburg, Robert; Opie, Alex; Walsh, Mike; Shen, Haiou; Butler, Anthony; Butler, Phillip; Mou, Xuanqin; Wang, Ge

    2012-06-01

    X-ray micro-CT is an important imaging tool for biomedical researchers. Our group has recently proposed a hybrid "true-color" micro-CT system to improve contrast resolution with lower system cost and radiation dose. The system incorporates an energy-resolved photon-counting true-color detector into a conventional micro-CT configuration, and can be used for material decomposition. In this paper, we demonstrate an interior color-CT image reconstruction algorithm developed for this hybrid true-color micro-CT system. A compressive sensing-based statistical interior tomography method is employed to reconstruct each channel in the local spectral imaging chain, where the reconstructed global gray-scale image from the conventional imaging chain served as the initial guess. Principal component analysis was used to map the spectral reconstructions into the color space. The proposed algorithm was evaluated by numerical simulations, physical phantom experiments, and animal studies. The results confirm the merits of the proposed algorithm, and demonstrate the feasibility of the hybrid true-color micro-CT system. Additionally, a "color diffusion" phenomenon was observed whereby high-quality true-color images are produced not only inside the region of interest, but also in neighboring regions. It appears harnessing that this phenomenon could potentially reduce the color detector size for a given ROI, further reducing system cost and radiation dose.

  3. Investigation of an SFOV hybrid gamma camera for thyroid imaging.

    PubMed

    Bugby, S L; Lees, J E; Ng, A H; Alqahtani, M S; Perkins, A C

    2016-01-01

    The Hybrid Compact Gamma Camera (HCGC) is a small field of view (SFOV) portable hybrid gamma-optical camera intended for small organ imaging at the patient bedside. In this study, a thyroid phantom was used to determine the suitability of the HCGC for clinical thyroid imaging through comparison with large field of view (LFOV) system performance. A direct comparison with LFOV contrast performance showed that the lower sensitivity of the HCGC had a detrimental effect on image quality. Despite this, the contrast of HCGC images exceeded those of the LFOV cameras for some image features particularly when a high-resolution pinhole collimator was used. A clinical simulation showed that thyroid morphology was visible in a 5 min integrated image acquisition with an expected dependency on the activity within the thyroid. The first clinical use of the HCGC for imaging thyroid uptake of (123)I is also presented. Measurements indicate that the HCGC has promising utility in thyroid imaging, particularly as its small size allows it to be brought into closer proximity with a patient. Future development of the energy response of the HCGC is expected to further improve image detectability.

  4. A statistical method for retrospective cardiac and respiratory motion gating of interventional cardiac x-ray images

    SciTech Connect

    Panayiotou, Maria King, Andrew P.; Housden, R. James; Ma, YingLiang; Rhode, Kawal S.; Cooklin, Michael; O'Neill, Mark; Gill, Jaswinder; Rinaldi, C. Aldo

    2014-07-15

    Purpose: Image-guided cardiac interventions involve the use of fluoroscopic images to guide the insertion and movement of interventional devices. Cardiorespiratory gating can be useful for 3D reconstruction from multiple x-ray views and for reducing misalignments between 3D anatomical models overlaid onto fluoroscopy. Methods: The authors propose a novel and potentially clinically useful retrospective cardiorespiratory gating technique. The principal component analysis (PCA) statistical method is used in combination with other image processing operations to make our proposed masked-PCA technique suitable for cardiorespiratory gating. Unlike many previously proposed techniques, our technique is robust to varying image-content, thus it does not require specific catheters or any other optically opaque structures to be visible. Therefore, it works without any knowledge of catheter geometry. The authors demonstrate the application of our technique for the purposes of retrospective cardiorespiratory gating of normal and very low dose x-ray fluoroscopy images. Results: For normal dose x-ray images, the algorithm was validated using 28 clinical electrophysiology x-ray fluoroscopy sequences (2168 frames), from patients who underwent radiofrequency ablation (RFA) procedures for the treatment of atrial fibrillation and cardiac resynchronization therapy procedures for heart failure. The authors established end-systole, end-expiration, and end-inspiration success rates of 97.0%, 97.9%, and 97.0%, respectively. For very low dose applications, the technique was tested on ten x-ray sequences from the RFA procedures with added noise at signal to noise ratio (SNR) values of√(5)0, √(1)0, √(8), √(6), √(5), √(2), and √(1) to simulate the image quality of increasingly lower dose x-ray images. Even at the low SNR value of √(2), representing a dose reduction of more than 25 times, gating success rates of 89.1%, 88.8%, and 86.8% were established. Conclusions: The proposed

  5. Dynamic real-time 4D cardiac MDCT image display using GPU-accelerated volume rendering.

    PubMed

    Zhang, Qi; Eagleson, Roy; Peters, Terry M

    2009-09-01

    Intraoperative cardiac monitoring, accurate preoperative diagnosis, and surgical planning are important components of minimally-invasive cardiac therapy. Retrospective, electrocardiographically (ECG) gated, multidetector computed tomographical (MDCT), four-dimensional (3D + time), real-time, cardiac image visualization is an important tool for the surgeon in such procedure, particularly if the dynamic volumetric image can be registered to, and fused with the actual patient anatomy. The addition of stereoscopic imaging provides a more intuitive environment by adding binocular vision and depth cues to structures within the beating heart. In this paper, we describe the design and implementation of a comprehensive stereoscopic 4D cardiac image visualization and manipulation platform, based on the opacity density radiation model, which exploits the power of modern graphics processing units (GPUs) in the rendering pipeline. In addition, we present a new algorithm to synchronize the phases of the dynamic heart to clinical ECG signals, and to calculate and compensate for latencies in the visualization pipeline. A dynamic multiresolution display is implemented to enable the interactive selection and emphasis of volume of interest (VOI) within the entire contextual cardiac volume and to enhance performance, and a novel color and opacity adjustment algorithm is designed to increase the uniformity of the rendered multiresolution image of heart. Our system provides a visualization environment superior to noninteractive software-based implementations, but with a rendering speed that is comparable to traditional, but inferior quality, volume rendering approaches based on texture mapping. This retrospective ECG-gated dynamic cardiac display system can provide real-time feedback regarding the suspected pathology, function, and structural defects, as well as anatomical information such as chamber volume and morphology.

  6. Wild-Type Transthyretin Cardiac Amyloidosis: Novel Insights From Advanced Imaging.

    PubMed

    Narotsky, David L; Castano, Adam; Weinsaft, Jonathan W; Bokhari, Sabahat; Maurer, Mathew S

    2016-09-01

    Amyloidosis is caused by extracellular deposition of abnormal protein fibrils, resulting in destruction of tissue architecture and impairment of organ function. The most common forms of systemic amyloidosis are light-chain and transthyretin-related (ATTR). ATTR can result from an autosomal dominant hereditary transmission of mutated genes in the transthyretin or from a wild-type form of disease (ATTRwt), previously known as senile cardiac amyloidosis. With the aging of the worldwide population, ATTRwt will emerge as the most common type of cardiac amyloidosis that clinicians encounter. Diagnosis of systemic amyloidosis is often delayed, either because of the false assumption that it is a rare disease, or because of misdiagnosis as a result of mistaking it with other conditions. Clinicians must integrate clinical clues from history, physical examination, and common diagnostic tests to raise suspicion for ATTRwt. The historical gold standard for diagnosis of cardiac amyloid is endomyocardial biopsy analysis with pathological distinction of precursor protein type, but this method often results in delayed diagnosis because of the limited availability of expertise to perform and interpret the endomyocardial biopsy specimen. Emerging noninvasive imaging modalities provide easier, accurate screening for ATTRwt. These modalities include advanced echocardiography, using strain imaging and the myocardial contraction fraction; nuclear scintigraphy, which can differentiate between ATTR and light-chain cardiac amyloid; and cardiac magnetic resonance imaging, using extracellular volume measurement, late gadolinium enhancement, and distinct T1 mapping. These novel approaches reveal insights into the prevalence, clinical course, morphological effects, and prognosis of ATTRwt. PMID:27568874

  7. A review of heart chamber segmentation for structural and functional analysis using cardiac magnetic resonance imaging.

    PubMed

    Peng, Peng; Lekadir, Karim; Gooya, Ali; Shao, Ling; Petersen, Steffen E; Frangi, Alejandro F

    2016-04-01

    Cardiovascular magnetic resonance (CMR) has become a key imaging modality in clinical cardiology practice due to its unique capabilities for non-invasive imaging of the cardiac chambers and great vessels. A wide range of CMR sequences have been developed to assess various aspects of cardiac structure and function, and significant advances have also been made in terms of imaging quality and acquisition times. A lot of research has been dedicated to the development of global and regional quantitative CMR indices that help the distinction between health and pathology. The goal of this review paper is to discuss the structural and functional CMR indices that have been proposed thus far for clinical assessment of the cardiac chambers. We include indices definitions, the requirements for the calculations, exemplar applications in cardiovascular diseases, and the corresponding normal ranges. Furthermore, we review the most recent state-of-the art techniques for the automatic segmentation of the cardiac boundaries, which are necessary for the calculation of the CMR indices. Finally, we provide a detailed discussion of the existing literature and of the future challenges that need to be addressed to enable a more robust and comprehensive assessment of the cardiac chambers in clinical practice.

  8. Low b-Value Diffusion-Weighted Cardiac Magnetic Resonance Imaging

    PubMed Central

    Rapacchi, Stanislas; Wen, Han; Viallon, Magalie; Grenier, Denis; Kellman, Peter; Croisille, Pierre; Pai, Vinay M.

    2012-01-01

    Objectives Diffusion-weighted imaging (DWI) using low b-values permits imaging of intravoxel incoherent motion in tissues. However, low b-value DWI of the human heart has been considered too challenging because of additional signal loss due to physiological motion, which reduces both signal intensity and the signal-to-noise ratio (SNR). We address these signal loss concerns by analyzing cardiac motion during a heartbeat to determine the time-window during which cardiac bulk motion is minimal. Using this information to optimize the acquisition of DWI data and combining it with a dedicated image processing approach has enabled us to develop a novel low b-value diffusion-weighted cardiac magnetic resonance imaging approach, which significantly reduces intravoxel incoherent motion measurement bias introduced by motion. Materials and Methods Simulations from displacement encoded motion data sets permitted the delineation of an optimal time-window with minimal cardiac motion. A number of single-shot repetitions of low b-value DWI cardiac magnetic resonance imaging data were acquired during this time-window under free-breathing conditions with bulk physiological motion corrected for by using nonrigid registration. Principal component analysis (PCA) was performed on the registered images to improve the SNR, and temporal maximum intensity projection (TMIP) was applied to recover signal intensity from time-fluctuant motion-induced signal loss. This PCATMIP method was validated with experimental data, and its benefits were evaluated in volunteers before being applied to patients. Results Optimal time-window cardiac DWI in combination with PCATMIP postprocessing yielded significant benefits for signal recovery, contrast-to-noise ratio, and SNR in the presence of bulk motion for both numerical simulations and human volunteer studies. Analysis of mean apparent diffusion coefficient (ADC) maps showed homogeneous values among volunteers and good reproducibility between free

  9. Automatic image-driven segmentation of cardiac ventricles in cine anatomical MRI

    NASA Astrophysics Data System (ADS)

    Cocosco, Chris A.; Niessen, Wiro J.; Netsch, Thomas; Vonken, Evert-jan P. A.; Viergever, Max A.

    2005-08-01

    The automatic segmentation of the heart's two ventricles from dynamic ("cine") cardiac anatomical images, such as 3D+time short-axis MRI, is of significant clinical importance. Previously published automated methods have various disadvantages for routine clinical use. This work reports about a novel automatic segmentation method that is very fast, and robust against anatomical variability and image contrast variations. The method is mostly image-driven: it fully exploits the information provided by modern 4D (3D+time) balanced Fast Field Echo (bFFE) cardiac anatomical MRI, and makes only few and plausible assumptions about the images and the imaged heart. Specifically, the method does not need any geometrical shape models nor complex gray-level appearance models. The method simply uses the two ventricles' contraction-expansion cycle, as well as the ventricles' spatial coherence along the time dimension. The performance of the cardiac ventricles segmentation method was demonstrated through a qualitative visual validation on 32 clinical exams: no gross failures for the left-ventricle (right-ventricle) on 32 (30) of the exams were found. Also, a clinical validation of resulting quantitative cardiac functional parameters was performed against a manual quantification of 18 exams; the automatically computed Ejection Fraction (EF) correlated well to the manually computed one: linear regression with RMS=3.7% (RMS expressed in EF units).

  10. Imaging of cardiac allograft rejection in dogs using indium-111 monoclonal antimyosin Fab

    SciTech Connect

    Addonizio, L.J.; Michler, R.E.; Marboe, C.; Esser, P.E.; Johnson, L.L.; Seldin, D.W.; Gersony, W.M.; Alderson, P.O.; Rose, E.A.; Cannon, P.J.

    1987-03-01

    The acute rejection of cardiac allografts is currently diagnosed by the presence of myocyte necrosis on endomyocardial biopsy. We evaluated the efficacy of noninvasive scintigraphic imaging with indium-111-labeled anticardiac myosin Fab fragments (indium-111 antimyosin) to detect and quantify cardiac allograft rejection. Six dogs that had intrathoracic heterotopic cardiac allograft transplantation were injected with indium-111 antimyosin and planar and single photon emission computed tomographic (SPECT) images were obtained in various stages of acute and subacute rejection. Four dogs had an allograft older than 8 months and had been on long-term immunosuppressive therapy; two dogs had an allograft less than 2 weeks old and were not on immunosuppressive therapy. Count ratios comparing heterotopic with native hearts were calculated from both SPECT images and in vitro scans of excised and sectioned hearts and were compared with the degree of rejection scored by an independent histopathologic review. Indium-111 antimyosin uptake was not visible in planar or SPECT images of native hearts. Faint diffuse uptake was apparent in cardiac allografts during long-term immunosuppression and intense radioactivity was present in hearts with electrocardiographic evidence of rejection. The heterotopic to native heart count ratios in SPECT images correlated significantly with the count ratios in the excised hearts (r = 0.93) and with the histopathologic rejection score (r = 0.97). The distribution of indium-111 antimyosin activity in right and left ventricles corresponded to areas of histopathologic abnormalities.

  11. Algebraic Reconstruction Technique (ART) for parallel imaging reconstruction of undersampled radial data: Application to cardiac cine

    PubMed Central

    Li, Shu; Chan, Cheong; Stockmann, Jason P.; Tagare, Hemant; Adluru, Ganesh; Tam, Leo K.; Galiana, Gigi; Constable, R. Todd; Kozerke, Sebastian; Peters, Dana C.

    2014-01-01

    Purpose To investigate algebraic reconstruction technique (ART) for parallel imaging reconstruction of radial data, applied to accelerated cardiac cine. Methods A GPU-accelerated ART reconstruction was implemented and applied to simulations, point spread functions (PSF) and in twelve subjects imaged with radial cardiac cine acquisitions. Cine images were reconstructed with radial ART at multiple undersampling levels (192 Nr x Np = 96 to 16). Images were qualitatively and quantitatively analyzed for sharpness and artifacts, and compared to filtered back-projection (FBP), and conjugate gradient SENSE (CG SENSE). Results Radial ART provided reduced artifacts and mainly preserved spatial resolution, for both simulations and in vivo data. Artifacts were qualitatively and quantitatively less with ART than FBP using 48, 32, and 24 Np, although FBP provided quantitatively sharper images at undersampling levels of 48-24 Np (all p<0.05). Use of undersampled radial data for generating auto-calibrated coil-sensitivity profiles resulted in slightly reduced quality. ART was comparable to CG SENSE. GPU-acceleration increased ART reconstruction speed 15-fold, with little impact on the images. Conclusion GPU-accelerated ART is an alternative approach to image reconstruction for parallel radial MR imaging, providing reduced artifacts while mainly maintaining sharpness compared to FBP, as shown by its first application in cardiac studies. PMID:24753213

  12. Automatic localization of the left ventricle in cardiac MRI images using deep learning.

    PubMed

    Emad, Omar; Yassine, Inas A; Fahmy, Ahmed S

    2015-08-01

    Automatic localization of the left ventricle (LV) in cardiac MRI images is an essential step for automatic segmentation, functional analysis, and content based retrieval of cardiac images. In this paper, we introduce a new approach based on deep Convolutional Neural Network (CNN) to localize the LV in cardiac MRI in short axis views. A six-layer CNN with different kernel sizes was employed for feature extraction, followed by Softmax fully connected layer for classification. The pyramids of scales analysis was introduced in order to take account of the different sizes of the heart. A publically-available database of 33 patients was used for learning and testing. The proposed method was able it localize the LV with 98.66%, 83.91% and 99.07% for accuracy, sensitivity and specificity respectively. PMID:26736354

  13. Biomechanically Constrained Multiframe Estimation of Nonrigid Cardiac Kinematics from Medical Image Sequence

    NASA Astrophysics Data System (ADS)

    Liu, Huafeng; Shi, Pengcheng

    2003-04-01

    Noninvasive estimation of soft tissue kinematics properties from medical image sequences has many important clinical and physiological implications, such as the diagnosis of heart diseases and the understanding of cardiac mechanics. In this paper, we present a biomechanics based strategy, framed as a priori constraints for the ill-posed motion recovery problems, that performs multi-frame estimation of the cardiac motion and deformation parameters. Constructing the heart dynamics system equations from biomechanics principles, we rely on techniques from statistical estimation theory and use a Kalman filter framework to generate smooth estimates of heart kinematics throughout the cardiac cycle. We will demonstrate the application of the strategy to estimate displacements and strains from in vivo left ventricular magnetic resonance image sequence, which provides initial displacement measures at the boundaries.

  14. Molecular imaging of macrophage enzyme activity in cardiac inflammation

    PubMed Central

    Ali, Muhammad; Pulli, Benjamin; Chen, John W.

    2014-01-01

    Molecular imaging is highly advantageous as various insidious inflammatory events can be imaged in a serial and quantitative fashion. Combined with the conventional imaging modalities like computed tomography (CT), magnetic resonance (MR) and nuclear imaging, it helps us resolve the extent of ongoing pathology, quantify inflammation and predict outcome. Macrophages are increasingly gaining importance as an imaging biomarker in inflammatory cardiovascular diseases. Macrophages, recruited to the site of injury, internalize necrotic or foreign material. Along with phagocytosis, activated macrophages release proteolytic enzymes like matrix metalloproteinases (MMPs) and cathepsins into the extracellular environment. Pro-inflammatory monocytes and macrophages also induce tissue oxidative damage through the inflammatory enzyme myeloperoxidase (MPO). In this review we will highlight recent advances in molecular macrophage imaging. Particular stress will be given to macrophage functional and enzymatic activity imaging which targets phagocytosis, proteolysis and myeloperoxidase activity imaging. PMID:24729833

  15. Cardiac Sarcoidosis or Giant Cell Myocarditis? On Treatment Improvement of Fulminant Myocarditis as Demonstrated by Cardiovascular Magnetic Resonance Imaging

    PubMed Central

    Bogabathina, Hari; Olson, Peter; Rathi, Vikas K.; Biederman, Robert W. W.

    2012-01-01

    Giant cell myocarditis, but not cardiac sarcoidosis, is known to cause fulminant myocarditis resulting in severe heart failure. However, giant cell myocarditis and cardiac sarcoidosis are pathologically similar, and attempts at pathological differentiation between the two remain difficult. We are presenting a case of fulminant myocarditis that has pathological features suggestive of cardiac sarcoidosis, but clinically mimicking giant cell myocarditis. This patient was treated with cyclosporine and prednisone and recovered well. This case we believe challenges our current understanding of these intertwined conditions. By obtaining a sense of severity of cardiac involvement via delayed hyperenhancement of cardiac magnetic resonance imaging, we were more inclined to treat this patient as giant cell myocarditis with cyclosporine. This resulted in excellent improvement of patient's cardiac function as shown by delayed hyperenhancement images, early perfusion images, and SSFP videos. PMID:24826266

  16. Colonization of multidrug resistant pathogens in a hybrid pediatric cardiac surgery center

    PubMed Central

    Haponiuk, Ireneusz; Steffens, Mariusz; Arlukowicz, Elzbieta; Irga-Jaworska, Ninela; Chojnicki, Maciej; Kwasniak, Ewelina; Zielinski, Jacek

    2016-01-01

    Introduction The incidence of multidrug resistant microorganisms worldwide is increasing. The aim of the study was to present institutional experience with the multidrug resistant microorganism colonization patterns observed in children with congenital heart diseases hospitalized in a hybrid pediatric cardiac surgery center. Material and methods Microbiological samples were routinely collected in all children admitted to our department. All microbiological samples were analyzed with regard to multidrug resistant microorganisms: methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Gram-negative rods producing extended-spectrum beta-lactamases (ESBL), multidrug resistant Gram-negative rods (MDR-GNRs), carbapenemase-producing Klebsiella pneumoniae (KPC), carbapenem-resistant Acinetobacter baumannii (CRAB) and Pseudomonas aeruginosa (CRPA). Results In 30 (9%) swabs ‘alert’ pathogens from the above group of listed microorganisms were found. All positive swabs were isolated in 19 (16.1%) children. Multidrug resistant pathogen colonization was statistically significantly more often observed in children admitted from other medical facilities than in children admitted from home (38% vs. 10%, p = 0.0089). In the group of children younger than 6 months ‘alert’ pathogen were more often observed than in older children (34.1% vs. 5.4%, p < 0.001). Conclusions Preoperative multidrug resistant pathogen screening in children admitted and referred for congenital heart disease procedures may be of great importance since many of these patients are colonized with resistant bacteria. Knowledge of the patient's microbiome is important in local epidemiological control along with tailoring the most effective preoperative prophylactic antibiotic for each patient. The impact of preoperative screening on postoperative infections and other complications requires further analysis. PMID:27279859

  17. 3D X-ray imaging methods in support catheter ablations of cardiac arrhythmias.

    PubMed

    Stárek, Zdeněk; Lehar, František; Jež, Jiří; Wolf, Jiří; Novák, Miroslav

    2014-10-01

    Cardiac arrhythmias are a very frequent illness. Pharmacotherapy is not very effective in persistent arrhythmias and brings along a number of risks. Catheter ablation has became an effective and curative treatment method over the past 20 years. To support complex arrhythmia ablations, the 3D X-ray cardiac cavities imaging is used, most frequently the 3D reconstruction of CT images. The 3D cardiac rotational angiography (3DRA) represents a modern method enabling to create CT like 3D images on a standard X-ray machine equipped with special software. Its advantage lies in the possibility to obtain images during the procedure, decreased radiation dose and reduction of amount of the contrast agent. The left atrium model is the one most frequently used for complex atrial arrhythmia ablations, particularly for atrial fibrillation. CT data allow for creation and segmentation of 3D models of all cardiac cavities. Recently, a research has been made proving the use of 3DRA to create 3D models of other cardiac (right ventricle, left ventricle, aorta) and non-cardiac structures (oesophagus). They can be used during catheter ablation of complex arrhythmias to improve orientation during the construction of 3D electroanatomic maps, directly fused with 3D electroanatomic systems and/or fused with fluoroscopy. An intensive development in the 3D model creation and use has taken place over the past years and they became routinely used during catheter ablations of arrhythmias, mainly atrial fibrillation ablation procedures. Further development may be anticipated in the future in both the creation and use of these models.

  18. Marketing image categorization using hybrid human-machine combinations

    NASA Astrophysics Data System (ADS)

    Gnanasambandam, Nathan; Madhu, Himanshu

    2012-03-01

    Marketing instruments with nested, short-form, symbol loaded content need to be studied differently. Image classification in the Web2.0 world can dynamically use a configurable amount of internal and external data as well as varying levels of crowd-sourcing. Our work is one such examination of how to construct a hybrid technique involving learning and crowd-sourcing. Through a parameter called turkmix and a multitude of crowd-sourcing techniques available we show that we can control the trend of metrics such as precision and recall on the hybrid categorizer.

  19. Hybrid lidar radar receiver for underwater imaging applications

    NASA Astrophysics Data System (ADS)

    Seetamraju, Madhavi; Gurjar, Rajan; Squillante, Michael; Derderian, Jeffrey P.

    2009-05-01

    In this work, we present research performed to improve the receiver characteristics for underwater imaging applications using the hybrid lidar-radar detection technique. We report the development of the next-generation coherent heterodyne receiver using modulation of the optical receiver's amplifier gain. Significant advantages in the receiver specifications are achieved using a large-area, high gain, low-noise silicon avalanche photodiode (APD) as the photodetector cum frequency mixer-demodulator. We demonstrate that heterodyne detection by gain modulation of APD can be used to increase the signal-to-noise ratio, detection sensitivity and bandwidth for the hybrid receiver system.

  20. Three-dimensional magnetic resonance cardiac imaging shows initial promise

    SciTech Connect

    Not Available

    1988-04-15

    Three-dimensional magnetic resonance imaging (3-D MRI) of the heart is already receiving encouraging reviews from heart surgeons, says Michael Vannier, MD, an associate professor of radiology at Washington University School of Medicine, St. Louis. In fact, the demand for his group's 3-D images is becoming overwhelming, Vannier says. So far, the group has used 3-D MRI to evaluate congenital heart disease. The advantage of the 3-D system is that, even to an untrained eye, anomalies are apparent and the images can even be animated. Many of the patients are infants, who are sedated while the images are acquired. When the information is combined, the averaged image produced represents a slice about 5 mm thick. The computer then stacks a number of those images together to make the 3-D image. Total scanning takes about one hour.

  1. Optimal Magnetic Sensor Vests for Cardiac Source Imaging.

    PubMed

    Lau, Stephan; Petković, Bojana; Haueisen, Jens

    2016-01-01

    Magnetocardiography (MCG) non-invasively provides functional information about the heart. New room-temperature magnetic field sensors, specifically magnetoresistive and optically pumped magnetometers, have reached sensitivities in the ultra-low range of cardiac fields while allowing for free placement around the human torso. Our aim is to optimize positions and orientations of such magnetic sensors in a vest-like arrangement for robust reconstruction of the electric current distributions in the heart. We optimized a set of 32 sensors on the surface of a torso model with respect to a 13-dipole cardiac source model under noise-free conditions. The reconstruction robustness was estimated by the condition of the lead field matrix. Optimization improved the condition of the lead field matrix by approximately two orders of magnitude compared to a regular array at the front of the torso. Optimized setups exhibited distributions of sensors over the whole torso with denser sampling above the heart at the front and back of the torso. Sensors close to the heart were arranged predominantly tangential to the body surface. The optimized sensor setup could facilitate the definition of a standard for sensor placement in MCG and the development of a wearable MCG vest for clinical diagnostics. PMID:27231910

  2. Optimal Magnetic Sensor Vests for Cardiac Source Imaging

    PubMed Central

    Lau, Stephan; Petković, Bojana; Haueisen, Jens

    2016-01-01

    Magnetocardiography (MCG) non-invasively provides functional information about the heart. New room-temperature magnetic field sensors, specifically magnetoresistive and optically pumped magnetometers, have reached sensitivities in the ultra-low range of cardiac fields while allowing for free placement around the human torso. Our aim is to optimize positions and orientations of such magnetic sensors in a vest-like arrangement for robust reconstruction of the electric current distributions in the heart. We optimized a set of 32 sensors on the surface of a torso model with respect to a 13-dipole cardiac source model under noise-free conditions. The reconstruction robustness was estimated by the condition of the lead field matrix. Optimization improved the condition of the lead field matrix by approximately two orders of magnitude compared to a regular array at the front of the torso. Optimized setups exhibited distributions of sensors over the whole torso with denser sampling above the heart at the front and back of the torso. Sensors close to the heart were arranged predominantly tangential to the body surface. The optimized sensor setup could facilitate the definition of a standard for sensor placement in MCG and the development of a wearable MCG vest for clinical diagnostics. PMID:27231910

  3. ICA based automatic segmentation of dynamic H(2)(15)O cardiac PET images.

    PubMed

    Margadán-Méndez, Margarita; Juslin, Anu; Nesterov, Sergey V; Kalliokoski, Kari; Knuuti, Juhani; Ruotsalainen, Ulla

    2010-05-01

    In this study, we applied an iterative independent component analysis (ICA) method for the separation of cardiac tissue components (myocardium, right, and left ventricle) from dynamic positron emission tomography (PET) images. Previous phantom and animal studies have shown that ICA separation extracts the cardiac structures accurately. Our goal in this study was to investigate the methodology with human studies. The ICA separated cardiac structures were used to calculate the myocardial perfusion in two different cases: 1) the regions of interest were drawn manually on the ICA separated component images and 2) the volumes of interest (VOI) were automatically segmented from the component images. For the whole myocardium, the perfusion values of 25 rest and six drug-induced stress studies obtained with these methods were compared to the values from the manually drawn regions of interest on differential images. The separation of the rest and stress studies using ICA-based methods was successful in all cases. The visualization of the cardiac structures from H (2) (15) O PET studies was improved with the ICA separation. Also, the automatic segmentation of the VOI seemed to be feasible. PMID:19273031

  4. Image-based models of cardiac structure in health and disease

    PubMed Central

    Vadakkumpadan, Fijoy; Arevalo, Hermenegild; Prassl, Anton J.; Chen, Junjie; Kickinger, Ferdinand; Kohl, Peter; Plank, Gernot; Trayanova, Natalia

    2010-01-01

    Computational approaches to investigating the electromechanics of healthy and diseased hearts are becoming essential for the comprehensive understanding of cardiac function. In this article, we first present a brief review of existing image-based computational models of cardiac structure. We then provide a detailed explanation of a processing pipeline which we have recently developed for constructing realistic computational models of the heart from high resolution structural and diffusion tensor (DT) magnetic resonance (MR) images acquired ex vivo. The presentation of the pipeline incorporates a review of the methodologies that can be used to reconstruct models of cardiac structure. In this pipeline, the structural image is segmented to reconstruct the ventricles, normal myocardium, and infarct. A finite element mesh is generated from the segmented structural image, and fiber orientations are assigned to the elements based on DTMR data. The methods were applied to construct seven different models of healthy and diseased hearts. These models contain millions of elements, with spatial resolutions in the order of hundreds of microns, providing unprecedented detail in the representation of cardiac structure for simulation studies. PMID:20582162

  5. Cardiac magnetic resonance imaging and computed tomography in ischemic cardiomyopathy: an update*

    PubMed Central

    Assunção, Fernanda Boldrini; de Oliveira, Diogo Costa Leandro; Souza, Vitor Frauches; Nacif, Marcelo Souto

    2016-01-01

    Ischemic cardiomyopathy is one of the major health problems worldwide, representing a significant part of mortality in the general population nowadays. Cardiac magnetic resonance imaging (CMRI) and cardiac computed tomography (CCT) are noninvasive imaging methods that serve as useful tools in the diagnosis of coronary artery disease and may also help in screening individuals with risk factors for developing this illness. Technological developments of CMRI and CCT have contributed to the rise of several clinical indications of these imaging methods complementarily to other investigation methods, particularly in cases where they are inconclusive. In terms of accuracy, CMRI and CCT are similar to the other imaging methods, with few absolute contraindications and minimal risks of adverse side-effects. This fact strengthens these methods as powerful and safe tools in the management of patients. The present study is aimed at describing the role played by CMRI and CCT in the diagnosis of ischemic cardiomyopathies. PMID:26929458

  6. Cardiac magnetic resonance imaging and computed tomography in ischemic cardiomyopathy: an update.

    PubMed

    Assunção, Fernanda Boldrini; de Oliveira, Diogo Costa Leandro; Souza, Vitor Frauches; Nacif, Marcelo Souto

    2016-01-01

    Ischemic cardiomyopathy is one of the major health problems worldwide, representing a significant part of mortality in the general population nowadays. Cardiac magnetic resonance imaging (CMRI) and cardiac computed tomography (CCT) are noninvasive imaging methods that serve as useful tools in the diagnosis of coronary artery disease and may also help in screening individuals with risk factors for developing this illness. Technological developments of CMRI and CCT have contributed to the rise of several clinical indications of these imaging methods complementarily to other investigation methods, particularly in cases where they are inconclusive. In terms of accuracy, CMRI and CCT are similar to the other imaging methods, with few absolute contraindications and minimal risks of adverse side-effects. This fact strengthens these methods as powerful and safe tools in the management of patients. The present study is aimed at describing the role played by CMRI and CCT in the diagnosis of ischemic cardiomyopathies. PMID:26929458

  7. Cardiac magnetic resonance imaging and computed tomography in ischemic cardiomyopathy: an update.

    PubMed

    Assunção, Fernanda Boldrini; de Oliveira, Diogo Costa Leandro; Souza, Vitor Frauches; Nacif, Marcelo Souto

    2016-01-01

    Ischemic cardiomyopathy is one of the major health problems worldwide, representing a significant part of mortality in the general population nowadays. Cardiac magnetic resonance imaging (CMRI) and cardiac computed tomography (CCT) are noninvasive imaging methods that serve as useful tools in the diagnosis of coronary artery disease and may also help in screening individuals with risk factors for developing this illness. Technological developments of CMRI and CCT have contributed to the rise of several clinical indications of these imaging methods complementarily to other investigation methods, particularly in cases where they are inconclusive. In terms of accuracy, CMRI and CCT are similar to the other imaging methods, with few absolute contraindications and minimal risks of adverse side-effects. This fact strengthens these methods as powerful and safe tools in the management of patients. The present study is aimed at describing the role played by CMRI and CCT in the diagnosis of ischemic cardiomyopathies.

  8. Novel reconstruction algorithm for multiphasic cardiac imaging using multislice helical CT

    NASA Astrophysics Data System (ADS)

    Cesmeli, Erdogan; Edic, Peter M.; Iatrou, Maria; Pfoh, Armin H.

    2001-06-01

    Cardiac imaging is still a challenge to CT reconstruction algorithms due to the dynamic nature of the heart. We have developed a new reconstruction technique, called the Flexible Algorithm, which achieves high temporal resolution while it is robust to heart-rate variations. The Flexible Algorithm, first, retrospectively tags helical CT views with corresponding cardiac phases obtained from associated EKG. Next, it determines a set of views for each slice, a stack of which covers the entire heart. Subsequently, the algorithm selects an optimum subset of views to achieve the highest temporal resolution for the desired cardiac phase. Finally, it spatiotemporally filters the views in the selected subsets to reconstruct slices. We tested the performance of our algorithm using both a dynamic analytical phantom and clinical data. Preliminary results indicate that the Flexible Algorithm obtains improved spatiotemporal resolution for a large range of heart rates and variations than standard algorithms do. By providing improved image quality at any desired cardiac phase, and robustness to heart rate variations, the Flexible Algorithm enables cardiac applications in CT, including those that benefit from multiphase information.

  9. Detectability of perfusion defect in five-dimensional gated-dynamic cardiac SPECT images

    PubMed Central

    Niu, Xiaofeng; Yang, Yongyi; King, Michael A.; Wernick, Miles N.

    2010-01-01

    Purpose: In previous work, the authors developed and demonstrated the concept of an image reconstruction procedure aimed to unify gated and dynamic nuclear cardiac imaging, which the authors have termed five-dimensional (5D) SPECT. Gated imaging permits the clinician to evaluate wall motion and, through the use of stress and rest scans, allows perfusion defects to be observed. Dynamic imaging depicts kinetics in the myocardium, which can be used to evaluate perfusion, but traditional dynamic images are motionless and do not depict wall motion. In this article, the authors investigate the degree to which perfusion defects can be detected from the dynamic information conveyed by 5D images, a problem that is particularly challenging in the absence of multiple fast camera rotations. Methods: The authors first demonstrate the usefulness of dynamic reconstructed images for perfusion detection by using linear discriminant analyses (Fisher linear discriminant analysis and principal component analysis) and a numerical channelized Hotelling observer. The authors then derive three types of discriminant metrics for characterizing the temporal kinetic information in reconstructed dynamic images for differentiating perfusion defects from normal cardiac perfusion, which are the Fisher linear discriminant map, temporal derivative map, and kinetic parametric images. Results: Results are based on the NURBS-based cardiac-torso phantom with simulation of Tc99m-teboroxime as the imaging agent. The derived metric maps and quantitative contrast-to-noise ratio results demonstrate that the reconstructed dynamic images could yield higher detectability of the perfusion defect than conventional gated reconstruction while providing wall motion information simultaneously. Conclusions: The proposed metrics can be used to produce new types of visualizations, showing wall motion and perfusion information, that may potentially be useful for clinical evaluation. Since 5D imaging permits wall motion

  10. Internet-based transfer of cardiac ultrasound images

    NASA Technical Reports Server (NTRS)

    Firstenberg, M. S.; Greenberg, N. L.; Garcia, M. J.; Morehead, A. J.; Cardon, L. A.; Klein, A. L.; Thomas, J. D.

    2000-01-01

    A drawback to large-scale multicentre studies is the time required for the centralized evaluation of diagnostic images. We evaluated the feasibility of digital transfer of echocardiographic images to a central laboratory for rapid and accurate interpretation. Ten patients undergoing trans-oesophageal echocardiographic scanning at three sites had representative single images and multiframe loops stored digitally. The images were analysed in the ordinary way. All images were then transferred via the Internet to a central laboratory and reanalysed by a different observer. The file sizes were 1.5-72 MByte and the transfer rates achieved were 0.6-4.8 Mbit/min. Quantitative measurements were similar between most on-site and central laboratory measurements (all P > 0.25), although measurements differed for left atrial width and pulmonary venous systolic velocities (both P < 0.05). Digital transfer of echocardiographic images and data to a central laboratory may be useful for multicentre trials.

  11. Hybrid imaging in planar scintigraphy: new implementations and historical precedents.

    PubMed

    Zuckier, Lionel S

    2012-01-01

    Fusion of tomographic radionuclide studies with anatomical examinations has become standard practice in positron emission tomography (PET) and single photon emission computed tomography (SPECT) imaging. Nonetheless, fusion of planar scintigraphic images with an anatomical modality remains distinctly uncommon, although methods to do so have appeared sporadically in the literature during the past 2 decades. In this article we review several techniques that have been used to combine planar scintigraphic images with radiographs and visual (photographic) images. Rigid or affine transformations have been performed to co-register the planar images with each other using custom, commercial, or public domain software. Display of the hybrid images has been achieved primarily with nonselective color-fusion methods. Promising efforts are underway to develop a technique of fusing planar lymphoscintigraphic images with CT topograms (scout images) obtained on the SPECT-CT camera in a manner that compensates for position-dependent variation in magnification that affects the CT scout. An advantage of this approach is that both of the component images are acquired on the same gantry, without need for repositioning of the patient. It is instructive to note that techniques of fusing rectilinear scans with radiographic and visual images were first developed more than 50 years ago. The revisiting of these methods after many decades reflects a fundamental need for spatial orientation in nuclear medicine that fusion imaging can also bring to planar scintigraphic studies.

  12. Evaluation of optical imaging and spectroscopy approaches for cardiac tissue depth assessment

    SciTech Connect

    Lin, B; Matthews, D; Chernomordik, V; Gandjbakhche, A; Lane, S; Demos, S G

    2008-02-13

    NIR light scattering from ex vivo porcine cardiac tissue was investigated to understand how imaging or point measurement approaches may assist development of methods for tissue depth assessment. Our results indicate an increase of average image intensity as thickness increases up to approximately 2 mm. In a dual fiber spectroscopy configuration, sensitivity up to approximately 3 mm with an increase to 6 mm when spectral ratio between selected wavelengths was obtained. Preliminary Monte Carlo results provided reasonable fit to the experimental data.

  13. Sparsely-Bonded CMOS Hybrid Imager

    NASA Technical Reports Server (NTRS)

    Cunningham, Thomas J. (Inventor); Hancock, Bruce R. (Inventor); Sun, Chao (Inventor); Jones, Todd J. (Inventor); Dickie, Matthew R. (Inventor); Nikzad, Shouleh (Inventor); Hoenk, Michael E. (Inventor); Wrigley, Christopher J. (Inventor); Newton, Kenneth W. (Inventor); Pain, Bedabrata (Inventor)

    2015-01-01

    A method and device for imaging or detecting electromagnetic radiation is provided. A device structure includes a first chip interconnected with a second chip. The first chip includes a detector array, wherein the detector array comprises a plurality of light sensors and one or more transistors. The second chip includes a Read Out Integrated Circuit (ROIC) that reads out, via the transistors, a signal produced by the light sensors. A number of interconnects between the ROIC and the detector array can be less than one per light sensor or pixel.

  14. Fluorescent In Situ Hybridization in Suspension by Imaging Flow Cytometry.

    PubMed

    Maguire, Orla; Wallace, Paul K; Minderman, Hans

    2016-01-01

    The emergence of imaging flow cytometry (IFC) has brought novel applications exploiting its advantages over conventional flow cytometry and microscopy. One of the new applications is fluorescence in situ hybridization in suspension (FISH-IS). Conventional FISH is a slide-based approach in which the spotlike imagery resulting from hybridization with fluorescently tagged probes is evaluated by fluorescence microscopy. The FISH-IS approach evaluated by IFC enables the evaluation of tens to hundreds of thousands of cells in suspension and the analysis can be automated and standardized diminishing operator bias from the analysis. The high cell number throughput of FISH-IS improves the detection of rare events compared to conventional FISH. The applicability of FISH-IS is currently limited to detection of abnormal quantitative differences of hybridization targets such as occur in numerical chromosome abnormalities, deletions and amplifications.Here, we describe a protocol for FISH-IS using chromosome enumeration probes as an example. PMID:27460240

  15. Assessment of Myocardial Infarction by Cardiac Magnetic Resonance Imaging and Long-Term Mortality

    PubMed Central

    Petriz, João Luiz Fernandes; Gomes, Bruno Ferraz de Oliveira; Rua, Braulio Santos; Azevedo, Clério Francisco; Hadlich, Marcelo Souza; Mussi, Henrique Thadeu Periard; Taets, Gunnar de Cunto; do Nascimento, Emília Matos; Pereira, Basílio de Bragança; e Silva, Nelson Albuquerque de Souza

    2015-01-01

    Background Cardiac magnetic resonance imaging provides detailed anatomical information on infarction. However, few studies have investigated the association of these data with mortality after acute myocardial infarction. Objective To study the association between data regarding infarct size and anatomy, as obtained from cardiac magnetic resonance imaging after acute myocardial infarction, and long-term mortality. Methods A total of 1959 reports of “infarct size” were identified in 7119 cardiac magnetic resonance imaging studies, of which 420 had clinical and laboratory confirmation of previous myocardial infarction. The variables studied were the classic risk factors – left ventricular ejection fraction, categorized ventricular function, and location of acute myocardial infarction. Infarct size and acute myocardial infarction extent and transmurality were analyzed alone and together, using the variable named “MET-AMI”. The statistical analysis was carried out using the elastic net regularization, with the Cox model and survival trees. Results The mean age was 62.3 ± 12 years, and 77.3% were males. During the mean follow-up of 6.4 ± 2.9 years, there were 76 deaths (18.1%). Serum creatinine, diabetes mellitus and previous myocardial infarction were independently associated with mortality. Age was the main explanatory factor. The cardiac magnetic resonance imaging variables independently associated with mortality were transmurality of acute myocardial infarction (p = 0.047), ventricular dysfunction (p = 0.0005) and infarcted size (p = 0.0005); the latter was the main explanatory variable for ischemic heart disease death. The MET-AMI variable was the most strongly associated with risk of ischemic heart disease death (HR: 16.04; 95%CI: 2.64-97.5; p = 0.003). Conclusion The anatomical data of infarction, obtained from cardiac magnetic resonance imaging after acute myocardial infarction, were independently associated with long-term mortality, especially for

  16. Free-breathing 3D cardiac MRI using iterative image-based respiratory motion correction.

    PubMed

    Moghari, Mehdi H; Roujol, Sébastien; Chan, Raymond H; Hong, Susie N; Bello, Natalie; Henningsson, Markus; Ngo, Long H; Goddu, Beth; Goepfert, Lois; Kissinger, Kraig V; Manning, Warren J; Nezafat, Reza

    2013-10-01

    Respiratory motion compensation using diaphragmatic navigator gating with a 5 mm gating window is conventionally used for free-breathing cardiac MRI. Because of the narrow gating window, scan efficiency is low resulting in long scan times, especially for patients with irregular breathing patterns. In this work, a new retrospective motion compensation algorithm is presented to reduce the scan time for free-breathing cardiac MRI that increasing the gating window to 15 mm without compromising image quality. The proposed algorithm iteratively corrects for respiratory-induced cardiac motion by optimizing the sharpness of the heart. To evaluate this technique, two coronary MRI datasets with 1.3 mm(3) resolution were acquired from 11 healthy subjects (seven females, 25 ± 9 years); one using a navigator with a 5 mm gating window acquired in 12.0 ± 2.0 min and one with a 15 mm gating window acquired in 7.1 ± 1.0 min. The images acquired with a 15 mm gating window were corrected using the proposed algorithm and compared to the uncorrected images acquired with the 5 and 15 mm gating windows. The image quality score, sharpness, and length of the three major coronary arteries were equivalent between the corrected images and the images acquired with a 5 mm gating window (P-value > 0.05), while the scan time was reduced by a factor of 1.7. PMID:23132549

  17. Radionuclide imaging of cardiac sympathetic innervation in heart failure: unlocking untapped potential.

    PubMed

    Gupta, Shuchita; Amanullah, Aman

    2015-03-01

    Heart failure (HF) is associated with sympathetic overactivity, which contributes to disease progression and arrhythmia development. Cardiac sympathetic innervation imaging can be performed using radiotracers that are taken up in the presynaptic nerve terminal of sympathetic nerves. The commonly used radiotracers are (123)I-metaiodobenzylguanidine ((123)I-mIBG) for planar and single-photon emission computed tomography imaging, and (11)C-hydroxyephedrine for positron emission tomography imaging. Sympathetic innervation imaging has been used in assessing prognosis, response to treatment, risk of ventricular arrhythmias and sudden death and prediction of response to cardiac resynchronization therapy in patients with HF. Other potential applications of these techniques are in patients with chemotherapy-induced cardiomyopathy, predicting myocardial recovery in patients with left ventricular assist devices, and assessing reinnervation following cardiac transplantation. There is a lack of standardization with respect to technique of (123)I-mIBG imaging that needs to be overcome for the imaging modality to gain popularity in clinical practice.

  18. Hybrid Image Fusion for Sharpness Enhancement of Multi-Spectral Lunar Images

    NASA Astrophysics Data System (ADS)

    Awumah, Anna; Mahanti, Prasun; Robinson, Mark

    2016-10-01

    Image fusion enhances the sharpness of a multi-spectral (MS) image by incorporating spatial details from a higher-resolution panchromatic (Pan) image [1,2]. Known applications of image fusion for planetary images are rare, although image fusion is well-known for its applications to Earth-based remote sensing. In a recent work [3], six different image fusion algorithms were implemented and their performances were verified with images from the Lunar Reconnaissance Orbiter (LRO) Camera. The image fusion procedure obtained a high-resolution multi-spectral (HRMS) product from the LRO Narrow Angle Camera (used as Pan) and LRO Wide Angle Camera (used as MS) images. The results showed that the Intensity-Hue-Saturation (IHS) algorithm results in a high-spatial quality product while the Wavelet-based image fusion algorithm best preserves spectral quality among all the algorithms. In this work we show the results of a hybrid IHS-Wavelet image fusion algorithm when applied to LROC MS images. The hybrid method provides the best HRMS product - both in terms of spatial resolution and preservation of spectral details. Results from hybrid image fusion can enable new science and increase the science return from existing LROC images.[1] Pohl, Cle, and John L. Van Genderen. "Review article multisensor image fusion in remote sensing: concepts, methods and applications." International journal of remote sensing 19.5 (1998): 823-854.[2] Zhang, Yun. "Understanding image fusion." Photogramm. Eng. Remote Sens 70.6 (2004): 657-661.[3] Mahanti, Prasun et al. "Enhancement of spatial resolution of the LROC Wide Angle Camera images." Archives, XXIII ISPRS Congress Archives (2016).

  19. 18F-NaF PET/CT Images of Cardiac Metastasis From Osteosarcoma.

    PubMed

    Chou, Yi-Hsien; Ko, Kuan-Yin; Cheng, Mei-Fang; Chen, Wei-Wu; Yen, Ruoh-Fang

    2016-09-01

    Osteosarcomas are aggressive with a high incidence of recurrence and metastasis. Cardiac osteosarcoma metastasis is rare. We described a 17-year-old boy who had right distal femoral osteosarcoma with lung metastases. During follow-up, right ventricular (RV) metastasis was noted and confirmed by histopathological examination of the surgical specimen. F-NaF PET/CT was then arranged 1 month after debulking surgery for residual tumor survey. The images showed intense F-NaF uptake at RV region, suggestive of residual cardiac metastases.

  20. MRI and FDG PET/CT imaging manifestations of cardiac sarcoidosis.

    PubMed

    Lu, Yang; Sweiss, Nadera J

    2015-12-01

    A 52-year-old man had biopsy-proven sarcoidosis of mediastinal lymph nodes. Cardiac sarcoidosis was confirmed on cardiac MRI with typical imaging features as delayed gadolinium enhancement. Follow-up FDG PET/CT with a 3-day pretest diet modification showed suppression of overall myocardial uptake of FDG but with multifocal abnormal FDG uptake in the myocardium regions corresponding to the previous MRI findings. Additional noncardiac active sarcoidosis involving multiple organ and lymph nodes were also visualized on FDG PET/CT. PMID:26544904

  1. 18F-NaF PET/CT Images of Cardiac Metastasis From Osteosarcoma.

    PubMed

    Chou, Yi-Hsien; Ko, Kuan-Yin; Cheng, Mei-Fang; Chen, Wei-Wu; Yen, Ruoh-Fang

    2016-09-01

    Osteosarcomas are aggressive with a high incidence of recurrence and metastasis. Cardiac osteosarcoma metastasis is rare. We described a 17-year-old boy who had right distal femoral osteosarcoma with lung metastases. During follow-up, right ventricular (RV) metastasis was noted and confirmed by histopathological examination of the surgical specimen. F-NaF PET/CT was then arranged 1 month after debulking surgery for residual tumor survey. The images showed intense F-NaF uptake at RV region, suggestive of residual cardiac metastases. PMID:27405028

  2. Influence of x-ray pulse parameters on the image quality for moving objects in digital cardiac imaging.

    PubMed

    Guibelalde, Eduardo; Vano, Eliseo; Vaquero, Francisco; González, Luciano

    2004-10-01

    The image quality of a single frame in a modern cardiac imaging x-ray facility can be improved by adjusting the automatic pulse exposure parameters. The effects of acquisition rate on patient dose and the detectability of moving objects have been fully described in scientific literature. However, the influence of automatic pulse exposure parameters is still to be determined. Images of a moving wheel (with lead wires) were acquired using an H5000 Philips Integris cardiac x-ray system. Poly(methylmethacrylate) plastic samples 20 and 30 cm thick were employed as the build-up phantom to simulate a patient. The images were obtained using preset clinical parameters for cardiac imaging procedures. The signal detectability and motion blur of a contrast bar at a transversal speed in the range of 100-150 mm/s were evaluated with a cine pulse width of 3, 5, 7, and 10 ms under automatic mA kV regulation. Two levels of exposure at the image intensifier entrance were included in this study. Signal detectability was analyzed in terms of the signal-to-noise ratio (SNR) and the value of SNR2/entrance surface dose. The blurring was modeled as a Gaussian-shaped blurring function, and the motion blur was expressed in terms of the peak full width at half maximum and amplitude (apparent contrast) of the resolution functions. A contrast bar simulating a vessel in motion at the maximum velocities of typical cardiac structures was exposed. Severe loss of image quality occurred at pulse widths > or =7 ms. It is also shown that below 5 ms static nonlinearities, likely caused by the need to use a large focus for cine acquisition, dominate the blurring process.

  3. Influence of x-ray pulse parameters on the image quality for moving objects in digital cardiac imaging

    SciTech Connect

    Guibelalde, Eduardo; Vano, Eliseo; Vaquero, Francisco; Gonzalez, Luciano

    2004-10-01

    The image quality of a single frame in a modern cardiac imaging x-ray facility can be improved by adjusting the automatic pulse exposure parameters. The effects of acquisition rate on patient dose and the detectability of moving objects have been fully described in scientific literature. However, the influence of automatic pulse exposure parameters is still to be determined. Images of a moving wheel (with lead wires) were acquired using an H5000 Philips Integris cardiac x-ray system. Poly(methylmethacrylate) plastic samples 20 and 30 cm thick were employed as the build-up phantom to simulate a patient. The images were obtained using preset clinical parameters for cardiac imaging procedures. The signal detectability and motion blur of a contrast bar at a transversal speed in the range of 100-150 mm/s were evaluated with a cine pulse width of 3, 5, 7, and 10 ms under automatic mA kV regulation. Two levels of exposure at the image intensifier entrance were included in this study. Signal detectability was analyzed in terms of the signal-to-noise ratio (SNR) and the value of SNR{sup 2}/entrance surface dose. The blurring was modeled as a Gaussian-shaped blurring function, and the motion blur was expressed in terms of the peak full width at half maximum and amplitude (apparent contrast) of the resolution functions. A contrast bar simulating a vessel in motion at the maximum velocities of typical cardiac structures was exposed. Severe loss of image quality occurred at pulse widths {>=}7 ms. It is also shown that below 5 ms static nonlinearities, likely caused by the need to use a large focus for cine acquisition, dominate the blurring process.

  4. Semi-automated scar detection in delayed enhanced cardiac magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Morisi, Rita; Donini, Bruno; Lanconelli, Nico; Rosengarden, James; Morgan, John; Harden, Stephen; Curzen, Nick

    2015-06-01

    Late enhancement cardiac magnetic resonance images (MRI) has the ability to precisely delineate myocardial scars. We present a semi-automated method for detecting scars in cardiac MRI. This model has the potential to improve routine clinical practice since quantification is not currently offered due to time constraints. A first segmentation step was developed for extracting the target regions for potential scar and determining pre-candidate objects. Pattern recognition methods are then applied to the segmented images in order to detect the position of the myocardial scar. The database of late gadolinium enhancement (LE) cardiac MR images consists of 111 blocks of images acquired from 63 patients at the University Hospital Southampton NHS Foundation Trust (UK). At least one scar was present for each patient, and all the scars were manually annotated by an expert. A group of images (around one third of the entire set) was used for training the system which was subsequently tested on all the remaining images. Four different classifiers were trained (Support Vector Machine (SVM), k-nearest neighbor (KNN), Bayesian and feed-forward neural network) and their performance was evaluated by using Free response Receiver Operating Characteristic (FROC) analysis. Feature selection was implemented for analyzing the importance of the various features. The segmentation method proposed allowed the region affected by the scar to be extracted correctly in 96% of the blocks of images. The SVM was shown to be the best classifier for our task, and our system reached an overall sensitivity of 80% with less than 7 false positives per patient. The method we present provides an effective tool for detection of scars on cardiac MRI. This may be of value in clinical practice by permitting routine reporting of scar quantification.

  5. Non-rigid dual respiratory and cardiac motion correction methods after, during, and before image reconstruction for 4D cardiac PET

    NASA Astrophysics Data System (ADS)

    Feng, Tao; Wang, Jizhe; Fung, George; Tsui, Benjamin

    2016-01-01

    Respiratory motion (RM) and cardiac motion (CM) degrade the quality and resolution in cardiac PET scans. We have developed non-rigid motion estimation methods to estimate both RM and CM based on 4D cardiac gated PET data alone, and compensate the dual respiratory and cardiac (R&C) motions after (MCAR), during (MCDR), and before (MCBR) image reconstruction. In all three R&C motion correction methods, attenuation-activity mismatch effect was modeled by using transformed attenuation maps using the estimated RM. The difference of using activity preserving and non-activity preserving models in R&C correction was also studied. Realistic Monte Carlo simulated 4D cardiac PET data using the 4D XCAT phantom and accurate models of the scanner design parameters and performance characteristics at different noise levels were employed as the known truth and for method development and evaluation. Results from the simulation study suggested that all three dual R&C motion correction methods provide substantial improvement in the quality of 4D cardiac gated PET images as compared with no motion correction. Specifically, the MCDR method yields the best performance for all different noise levels compared with the MCAR and MCBR methods. While MCBR reduces computational time dramatically but the resultant 4D cardiac gated PET images has overall inferior image quality when compared to that from the MCAR and MCDR approaches in the ‘almost’ noise free case. Also, the MCBR method has better noise handling properties when compared with MCAR and provides better quantitative results in high noise cases. When the goal is to reduce scan time or patient radiation dose, MCDR and MCBR provide a good compromise between image quality and computational times.

  6. Non-rigid dual respiratory and cardiac motion correction methods after, during, and before image reconstruction for 4D cardiac PET.

    PubMed

    Feng, Tao; Wang, Jizhe; Fung, George; Tsui, Benjamin

    2016-01-01

    Respiratory motion (RM) and cardiac motion (CM) degrade the quality and resolution in cardiac PET scans. We have developed non-rigid motion estimation methods to estimate both RM and CM based on 4D cardiac gated PET data alone, and compensate the dual respiratory and cardiac (R&C) motions after (MCAR), during (MCDR), and before (MCBR) image reconstruction. In all three R&C motion correction methods, attenuation-activity mismatch effect was modeled by using transformed attenuation maps using the estimated RM. The difference of using activity preserving and non-activity preserving models in R&C correction was also studied. Realistic Monte Carlo simulated 4D cardiac PET data using the 4D XCAT phantom and accurate models of the scanner design parameters and performance characteristics at different noise levels were employed as the known truth and for method development and evaluation. Results from the simulation study suggested that all three dual R&C motion correction methods provide substantial improvement in the quality of 4D cardiac gated PET images as compared with no motion correction. Specifically, the MCDR method yields the best performance for all different noise levels compared with the MCAR and MCBR methods. While MCBR reduces computational time dramatically but the resultant 4D cardiac gated PET images has overall inferior image quality when compared to that from the MCAR and MCDR approaches in the 'almost' noise free case. Also, the MCBR method has better noise handling properties when compared with MCAR and provides better quantitative results in high noise cases. When the goal is to reduce scan time or patient radiation dose, MCDR and MCBR provide a good compromise between image quality and computational times.

  7. Dynamic flat panel detector versus image intensifier in cardiac imaging: dose and image quality

    NASA Astrophysics Data System (ADS)

    Vano, E.; Geiger, B.; Schreiner, A.; Back, C.; Beissel, J.

    2005-12-01

    The practical aspects of the dosimetric and imaging performance of a digital x-ray system for cardiology procedures were evaluated. The system was configured with an image intensifier (II) and later upgraded to a dynamic flat panel detector (FD). Entrance surface air kerma (ESAK) to phantoms of 16, 20, 24 and 28 cm of polymethyl methacrylate (PMMA) and the image quality of a test object were measured. Images were evaluated directly on the monitor and with numerical methods (noise and signal-to-noise ratio). Information contained in the DICOM header for dosimetry audit purposes was also tested. ESAK values per frame (or kerma rate) for the most commonly used cine and fluoroscopy modes for different PMMA thicknesses and for field sizes of 17 and 23 cm for II, and 20 and 25 cm for FD, produced similar results in the evaluated system with both technologies, ranging between 19 and 589 µGy/frame (cine) and 5 and 95 mGy min-1 (fluoroscopy). Image quality for these dose settings was better for the FD version. The 'study dosimetric report' is comprehensive, and its numerical content is sufficiently accurate. There is potential in the future to set those systems with dynamic FD to lower doses than are possible in the current II versions, especially for digital cine runs, or to benefit from improved image quality.

  8. Quantitative imaging of intact cardiac tissue using remote focusing microscopy

    NASA Astrophysics Data System (ADS)

    Corbett, A. D.; Burton, R. A. B.; Bub, G.; Wilson, T.

    2015-03-01

    Remote focussing microscopy offers many advantages when acquiring volumetric data from living tissue. The all-optical means of refocussing does not agitate the specimen by moving either the stage or imaging objective. Aberrationcompensated imaging extends over volumes as large as 450 μm x 450 μm x 200 μm (X, Y and Z) allowing data to be collected from hundreds of cells. The speed with which refocussing can be achieved is limited only by the mechanical movement of a small (2 mm diameter) mirror. Using a pair of oblique imaging planes to rapidly acquire (<200ms) depth information temporally freezes residual tissue motion in the arrested heart. This paper discusses the progress of remote focussing microscopy from a novel imaging technique to a reliable tool in the life sciences. Specifically, we describe recent efforts to achieve the accurate calibration of both distance and orientation within the imaging volume. Using a laser machined fluorescent specimen it is possible to identify, with high sensitivity, small (<1%) depth-dependent magnification changes which are a linear function of axial misalignment of the imaging objective. The sensitivity of the calibration procedure limits distortion to <1 μm over the entire imaging volume. This work finds direct application in identifying the microscopic effects of chronic disease in the living heart.

  9. STEM image simulation with hybrid CPU/GPU programming.

    PubMed

    Yao, Y; Ge, B H; Shen, X; Wang, Y G; Yu, R C

    2016-07-01

    STEM image simulation is achieved via hybrid CPU/GPU programming under parallel algorithm architecture to speed up calculation on a personal computer (PC). To utilize the calculation power of a PC fully, the simulation is performed using the GPU core and multi-CPU cores at the same time to significantly improve efficiency. GaSb and an artificial GaSb/InAs interface with atom diffusion have been used to verify the computation.

  10. Findings of Cardiac Magnetic Resonance Imaging in Hypertrophic Cardiomyopathy after 16 Years

    PubMed Central

    Kim, Gee-Hee; Jang, Bo-Hyun; Lee, Hyeong-Han; Hong, Solim; Eum, Sang-Hoon; Jeon, Howook; Moon, Donggyu

    2016-01-01

    A 58-year-old man had been diagnosed with non-obstructive hypertrophic cardiomyopathy (HCMP) according to echocardiography findings 16 years ago. Echocardiography showed ischemic cardiomyopathy (CMP)-like features with decreased systolic function but a non-dilated chamber. Coronary angiography was performed but showed a normal coronary artery. Cardiac magnetic resonance imaging (MRI) revealed multifocal transmural and subepicardial delayed-enhancing areas at the anteroseptal, septal, and inferoseptal left ventricular (LV) wall, and wall thinning and decreased motion of the anteroseptal LV wall. Findings of ischemic CMP-like features by echocardiography suggested microvascular dysfunction. This late stage of HCMP carries a high risk of sudden death. Cardiac MRI evaluation may be necessary in cases of ischemic CMP-like features in HCMP. In this case, the diagnosis of end-stage HCMP with microvascular dysfunction was confirmed by using cardiac MRI after a follow-up period of more than 16 years. PMID:27721955

  11. Cardiac Motion Analysis Using High-Speed Video Images in a Rat Model for Myocardial Infarction

    NASA Astrophysics Data System (ADS)

    Ishii, Idaku; Okuda, Toshikazu; Nie, Yuman; Takaki, Takeshi; Orito, Kensuke; Tanaka, Akane; Matsuda, Hiroshi

    In this study, we performed a cardiac motion analysis by using 1000-frames per second (fps) stereo images to capture the three-dimensional motion of small color markers in a rat heart. This method of recording cardiac motion could quantify the rate of change in the myocardial area, which indicated localized myocardial activity of rhythmic expansion and contraction. We analyzed the three-dimensional motion distributions in a rat model for myocardial infarction, in which the heart rate was 4 times/s or more. In the analysis, we spatiotemporally quantified the characteristic cardiac motion in ischemic heart diseases and found that infarction due to ischemia in the rat heart was spread around the left ventricle.

  12. Intravital imaging of cardiac function at the single-cell level

    PubMed Central

    Aguirre, Aaron D.; Vinegoni, Claudio; Sebas, Matt; Weissleder, Ralph

    2014-01-01

    Knowledge of cardiomyocyte biology is limited by the lack of methods to interrogate single-cell physiology in vivo. Here we show that contracting myocytes can indeed be imaged with optical microscopy at high temporal and spatial resolution in the beating murine heart, allowing visualization of individual sarcomeres and measurement of the single cardiomyocyte contractile cycle. Collectively, this has been enabled by efficient tissue stabilization, a prospective real-time cardiac gating approach, an image processing algorithm for motion-artifact-free imaging throughout the cardiac cycle, and a fluorescent membrane staining protocol. Quantification of cardiomyocyte contractile function in vivo opens many possibilities for investigating myocardial disease and therapeutic intervention at the cellular level. PMID:25053815

  13. Automatic detection of cardiac contours on MR images using fuzzy logic and dynamic programming.

    PubMed

    Lalande, A; Legrand, L; Walker, P M; Jaulent, M C; Guy, F; Cottin, Y; Brunotte, F

    1997-01-01

    This paper deals with the use of fuzzy logic and dynamic programming in the detection of cardiac contours in MR Images. The definition of two parameters for each pixel allows the construction of the fuzzy set of the cardiac contour points. The first parameter takes into account the grey level, and the second the presence of an edge. A corresponding fuzzy matrix is derived from the initial image. Finally, a dynamic programming with graph searching is performed on this fuzzy matrix. The method has been tested on several MR images and the results of the contouring were validated by an expert in the domain. This preliminary work clearly demonstrates the interest of this method, although a formal evaluation has to be done.

  14. Calibration free beam hardening correction for cardiac CT perfusion imaging

    NASA Astrophysics Data System (ADS)

    Levi, Jacob; Fahmi, Rachid; Eck, Brendan L.; Fares, Anas; Wu, Hao; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    Myocardial perfusion imaging using CT (MPI-CT) and coronary CTA have the potential to make CT an ideal noninvasive gate-keeper for invasive coronary angiography. However, beam hardening artifacts (BHA) prevent accurate blood flow calculation in MPI-CT. BH Correction (BHC) methods require either energy-sensitive CT, not widely available, or typically a calibration-based method. We developed a calibration-free, automatic BHC (ABHC) method suitable for MPI-CT. The algorithm works with any BHC method and iteratively determines model parameters using proposed BHA-specific cost function. In this work, we use the polynomial BHC extended to three materials. The image is segmented into soft tissue, bone, and iodine images, based on mean HU and temporal enhancement. Forward projections of bone and iodine images are obtained, and in each iteration polynomial correction is applied. Corrections are then back projected and combined to obtain the current iteration's BHC image. This process is iterated until cost is minimized. We evaluate the algorithm on simulated and physical phantom images and on preclinical MPI-CT data. The scans were obtained on a prototype spectral detector CT (SDCT) scanner (Philips Healthcare). Mono-energetic reconstructed images were used as the reference. In the simulated phantom, BH streak artifacts were reduced from 12+/-2HU to 1+/-1HU and cupping was reduced by 81%. Similarly, in physical phantom, BH streak artifacts were reduced from 48+/-6HU to 1+/-5HU and cupping was reduced by 86%. In preclinical MPI-CT images, BHA was reduced from 28+/-6 HU to less than 4+/-4HU at peak enhancement. Results suggest that the algorithm can be used to reduce BHA in conventional CT and improve MPI-CT accuracy.

  15. Automatic quantitative analysis of cardiac MR perfusion images

    NASA Astrophysics Data System (ADS)

    Breeuwer, Marcel M.; Spreeuwers, Luuk J.; Quist, Marcel J.

    2001-07-01

    Magnetic Resonance Imaging (MRI) is a powerful technique for imaging cardiovascular diseases. The introduction of cardiovascular MRI into clinical practice is however hampered by the lack of efficient and accurate image analysis methods. This paper focuses on the evaluation of blood perfusion in the myocardium (the heart muscle) from MR images, using contrast-enhanced ECG-triggered MRI. We have developed an automatic quantitative analysis method, which works as follows. First, image registration is used to compensate for translation and rotation of the myocardium over time. Next, the boundaries of the myocardium are detected and for each position within the myocardium a time-intensity profile is constructed. The time interval during which the contrast agent passes for the first time through the left ventricle and the myocardium is detected and various parameters are measured from the time-intensity profiles in this interval. The measured parameters are visualized as color overlays on the original images. Analysis results are stored, so that they can later on be compared for different stress levels of the heart. The method is described in detail in this paper and preliminary validation results are presented.

  16. Current Status of Hybrid PET/MRI in Oncologic Imaging

    PubMed Central

    Rosenkrantz, Andrew B.; Friedman, Kent; Chandarana, Hersh; Melsaether, Amy; Moy, Linda; Ding, Yu-Shin; Jhaveri, Komal; Beltran, Luis; Jain, Rajan

    2016-01-01

    OBJECTIVE This review article explores recent advancements in PET/MRI for clinical oncologic imaging. CONCLUSION Radiologists should understand the technical considerations that have made PET/MRI feasible within clinical workflows, the role of PET tracers for imaging various molecular targets in oncology, and advantages of hybrid PET/MRI compared with PET/CT. To facilitate this understanding, we discuss clinical examples (including gliomas, breast cancer, bone metastases, prostate cancer, bladder cancer, gynecologic malignancy, and lymphoma) as well as future directions, challenges, and areas for continued technical optimization for PET/MRI. PMID:26491894

  17. In vivo imaging of cardiac development and function in zebrafish using light sheet microscopy.

    PubMed

    Weber, Michael; Huisken, Jan

    2015-01-01

    Detailed studies of heart development and function are crucial for our understanding of cardiac failures and pave the way for better diagnostics and treatment. However, the constant motion and close incorporation into the cardiovascular system prevent in vivo studies of the living, unperturbed heart. The complementary strengths of the zebrafish model and light sheet microscopy provide a useful platform to fill this gap. High-resolution images of the embryonic vertebrate heart are now recorded from within the living animal: deep inside the unperturbed heart we can follow cardiac contractions and measure action potentials and calcium transients. Three-dimensional reconstructions of the entire beating heart with cellular resolution give new insights into its ever-changing morphology and facilitate studies into how individual cells form the complex cardiac network. In addition, cardiac dynamics and robustness are now examined with targeted optical manipulation. Overall, the combination of zebrafish and light sheet microscopy represents a promising addition for cardiac research and opens the door to a better understanding of heart function and development.

  18. Effects of cardiac pulsation in diffusion tensor imaging of the rat brain

    PubMed Central

    Kim, Sungheon; Pickup, Stephen; Poptani, Harish

    2010-01-01

    The purpose of this study was to investigate the effects of cardiac pulsation in diffusion tensor imaging (DTI) of the rat brain. DTI data were acquired either with or without different cardiac gating delays. For each case, two sets of identical DTI data were acquired for a bootstrap analysis to measure the uncertainty in estimating mean diffusivity (MD), fractional anisotropy (FA) and the primary eigenvector direction. The 95% confidence interval of the primary eigenvectors was substantially reduced (21 ~ 25 %) when cardiac gating with triggering delay of 70 ms (~ half of R-R peak duration) was used in comparison to studies without gating or when gating with a triggering delay of 0 ms was used. Standard deviations of MD and FA estimates were also reduced by 12 – 26 % and 13 – 24 %, respectively. For voxels with mean FA values larger than 0.15 and smaller than 0.95, the decrease in CI and standard deviations of MD and FA by cardiac gating with triggering delay of 70 ms were significant (p < 0.05). These results demonstrate the importance of cardiac gating in acquisition of in vivo high resolution DTI data. PMID:20951164

  19. Cardiac sarcoidosis mimicking hypertrophic cardiomyopathy: clinical utility of radionuclide imaging for differential diagnosis.

    PubMed

    Yazaki, Y; Isobe, M; Hayasaka, M; Tanaka, M; Fujii, T; Sekiguchi, M

    1998-06-01

    A 62-year-old woman with skin sarcoidosis was admitted to our hospital to ascertain whether she had cardiac involvement. Although she displayed no cardiac signs or symptoms, the electrocardiogram showed first-degree atrioventricular block, right bundle branch block with left anterior fascicular block, and giant negative T waves in the V3 lead. Echocardiography revealed marked hypertrophy localized in the basal portion of the interventricular septum (IVS) without systolic dysfunction, mimicking hypertrophic cardiomyopathy (HCM). Exercise thallium-201 myocardial imaging revealed redistribution in the anteroseptal region. Both gallium-67 (67Ga) and technetium-99m pyrophosphate (99mTc-PYP) scintigraphy revealed abnormal uptake in the myocardium. These findings disappeared after 2 months of steroid treatment. Reports of cardiac sarcoidosis mimicking HCM are rare. However, hypertrophy in the basal portion of the IVS is an important sign of early cardiac involvement in sarcoidosis. 67Ga and 99mTc-PYP scintigraphy were useful and necessary to differentiate this type of cardiac sarcoidosis from HCM.

  20. A visible light imaging device for cardiac rate detection with reduced effect of body movement

    NASA Astrophysics Data System (ADS)

    Jiang, Xiaotian; Liu, Ming; Zhao, Yuejin

    2014-09-01

    A visible light imaging system to detect human cardiac rate is proposed in this paper. A color camera and several LEDs, acting as lighting source, were used to avoid the interference of ambient light. From people's forehead, the cardiac rate could be acquired based on photoplethysmography (PPG) theory. The template matching method was used after the capture of video. The video signal was discomposed into three signal channels (RGB) and the region of interest was chosen to take the average gray value. The green channel signal could provide an excellent waveform of pulse wave on the account of green lights' absorptive characteristics of blood. Through the fast Fourier transform, the cardiac rate was exactly achieved. But the research goal was not just to achieve the cardiac rate accurately. With the template matching method, the effects of body movement are reduced to a large extent, therefore the pulse wave can be detected even while people are in the moving state and the waveform is largely optimized. Several experiments are conducted on volunteers, and the results are compared with the ones gained by a finger clamped pulse oximeter. The contrast results between these two ways are exactly agreeable. This method to detect the cardiac rate and the pulse wave largely reduces the effects of body movement and can probably be widely used in the future.

  1. In vivo imaging of cardiac development and function in zebrafish using light sheet microscopy.

    PubMed

    Weber, Michael; Huisken, Jan

    2015-01-01

    Detailed studies of heart development and function are crucial for our understanding of cardiac failures and pave the way for better diagnostics and treatment. However, the constant motion and close incorporation into the cardiovascular system prevent in vivo studies of the living, unperturbed heart. The complementary strengths of the zebrafish model and light sheet microscopy provide a useful platform to fill this gap. High-resolution images of the embryonic vertebrate heart are now recorded from within the living animal: deep inside the unperturbed heart we can follow cardiac contractions and measure action potentials and calcium transients. Three-dimensional reconstructions of the entire beating heart with cellular resolution give new insights into its ever-changing morphology and facilitate studies into how individual cells form the complex cardiac network. In addition, cardiac dynamics and robustness are now examined with targeted optical manipulation. Overall, the combination of zebrafish and light sheet microscopy represents a promising addition for cardiac research and opens the door to a better understanding of heart function and development. PMID:26700795

  2. An event-driven distributed processing architecture for image-guided cardiac ablation therapy.

    PubMed

    Rettmann, M E; Holmes, D R; Cameron, B M; Robb, R A

    2009-08-01

    Medical imaging data is becoming increasing valuable in interventional medicine, not only for preoperative planning, but also for real-time guidance during clinical procedures. Three key components necessary for image-guided intervention are real-time tracking of the surgical instrument, aligning the real-world patient space with image-space, and creating a meaningful display that integrates the tracked instrument and patient data. Issues to consider when developing image-guided intervention systems include the communication scheme, the ability to distribute CPU intensive tasks, and flexibility to allow for new technologies. In this work, we have designed a communication architecture for use in image-guided catheter ablation therapy. Communication between the system components is through a database which contains an event queue and auxiliary data tables. The communication scheme is unique in that each system component is responsible for querying and responding to relevant events from the centralized database queue. An advantage of the architecture is the flexibility to add new system components without affecting existing software code. In addition, the architecture is intrinsically distributed, in that components can run on different CPU boxes, and even different operating systems. We refer to this Framework for Image-Guided Navigation using a Distributed Event-Driven Database in Real-Time as the FINDER architecture. This architecture has been implemented for the specific application of image-guided cardiac ablation therapy. We describe our prototype image-guidance system and demonstrate its functionality by emulating a cardiac ablation procedure with a patient-specific phantom. The proposed architecture, designed to be modular, flexible, and intuitive, is a key step towards our goal of developing a complete system for visualization and targeting in image-guided cardiac ablation procedures.

  3. Determining velocity displacement field from cardiac image sequence

    NASA Astrophysics Data System (ADS)

    Meyering, Wietske I.; Gutierrez, Marco A.; Robilotta, Cecil C.; Furuie, Sergio S.

    2002-04-01

    Estimation of left ventricle motion and deformation from series of images has been an area of attention in the medical image analysis and still remains an open and challenging problem. Left ventricle contractile abnormalities can be an important manifestation of coronary artery disease. The proper motion tracking of left ventricle wall can contribute to isolate the location and extent of ischemic or infarcted myocardium and constitutes a fundamental goal of image modalities, such as Nuclear Medicine. This work describes a method to automatically estimate the velocity vector field for a beating heart based on the study of variation in frequency content in a series of 2D images as time varies. The frequency analysis is performed by computing the Wigner-Ville and the Choi-Williams distributions to each image pixel, yielding the corresponding 3D-frequency spectrum. From this 3D spectrum the local velocity of each pixel is calculated by employing a multiple linear regression model. Experimental validation was carried out using synthetic phantoms that simulate translation and rotation between successive frames. Results obtained from gated SPECT perfusion studies are also presented.

  4. An efficient method for accurate segmentation of LV in contrast-enhanced cardiac MR images

    NASA Astrophysics Data System (ADS)

    Suryanarayana K., Venkata; Mitra, Abhishek; Srikrishnan, V.; Jo, Hyun Hee; Bidesi, Anup

    2016-03-01

    Segmentation of left ventricle (LV) in contrast-enhanced cardiac MR images is a challenging task because of high variability in the image intensity. This is due to a) wash-in and wash-out of the contrast agent over time and b) poor contrast around the epicardium (outer wall) region. Current approaches for segmentation of the endocardium (inner wall) usually involve application of a threshold within the region of interest, followed by refinement techniques like active contours. A limitation of this method is under-segmentation of the inner wall because of gradual loss of contrast at the wall boundary. On the other hand, the challenge in outer wall segmentation is the lack of reliable boundaries because of poor contrast. There are four main contributions in this paper to address the aforementioned issues. First, a seed image is selected using variance based approach on 4D time-frame images over which initial endocardium and epicardium is segmented. Secondly, we propose a patch based feature which overcomes the problem of gradual contrast loss for LV endocardium segmentation. Third, we propose a novel Iterative-Edge-Refinement (IER) technique for epicardium segmentation. Fourth, we propose a greedy search algorithm for propagating the initial contour segmented on seed-image across other time frame images. We have experimented our technique on five contrast-enhanced cardiac MR Datasets (4D) having a total of 1097 images. The segmentation results for all 1097 images have been visually inspected by a clinical expert and have shown good accuracy.

  5. Hybrid CMOS SiPIN detectors as astronomical imagers

    NASA Astrophysics Data System (ADS)

    Simms, Lance Michael

    Charge Coupled Devices (CCDs) have dominated optical and x-ray astronomy since their inception in 1969. Only recently, through improvements in design and fabrication methods, have imagers that use Complimentary Metal Oxide Semiconductor (CMOS) technology gained ground on CCDs in scientific imaging. We are now in the midst of an era where astronomers might begin to design optical telescope cameras that employ CMOS imagers. The first three chapters of this dissertation are primarily composed of introductory material. In them, we discuss the potential advantages that CMOS imagers offer over CCDs in astronomical applications. We compare the two technologies in terms of the standard metrics used to evaluate and compare scientific imagers: dark current, read noise, linearity, etc. We also discuss novel features of CMOS devices and the benefits they offer to astronomy. In particular, we focus on a specific kind of hybrid CMOS sensor that uses Silicon PIN photodiodes to detect optical light in order to overcome deficiencies of commercial CMOS sensors. The remaining four chapters focus on a specific type of hybrid CMOS Silicon PIN sensor: the Teledyne Hybrid Visible Silicon PIN Imager (HyViSI). In chapters four and five, results from testing HyViSI detectors in the laboratory and at the Kitt Peak 2.1m telescope are presented. We present our laboratory measurements of the standard detector metrics for a number of HyViSI devices, ranging from 1k×1k to 4k×4k format. We also include a description of the SIDECAR readout circuit that was used to control the detectors. We then show how they performed at the telescope in terms of photometry, astrometry, variability measurement, and telescope focusing and guiding. Lastly, in the final two chapters we present results on detector artifacts such as pixel crosstalk, electronic crosstalk, and image persistence. One form of pixel crosstalk that has not been discussed elsewhere in the literature, which we refer to as Interpixel Charge

  6. Synergistic image reconstruction for hybrid ultrasound and photoacoustic computed tomography

    NASA Astrophysics Data System (ADS)

    Matthews, Thomas P.; Wang, Kun; Wang, Lihong V.; Anastasio, Mark A.

    2015-03-01

    Conventional photoacoustic computed tomography (PACT) image reconstruction methods assume that the object and surrounding medium are described by a constant speed-of-sound (SOS) value. In order to accurately recover fine structures, SOS heterogeneities should be quantified and compensated for during PACT reconstruction. To address this problem, several groups have proposed hybrid systems that combine PACT with ultrasound computed tomography (USCT). In such systems, a SOS map is reconstructed first via USCT. Consequently, this SOS map is employed to inform the PACT reconstruction method. Additionally, the SOS map can provide structural information regarding tissue, which is complementary to the functional information from the PACT image. We propose a paradigm shift in the way that images are reconstructed in hybrid PACT-USCT imaging. Inspired by our observation that information about the SOS distribution is encoded in PACT measurements, we propose to jointly reconstruct the absorbed optical energy density and SOS distributions from a combined set of USCT and PACT measurements, thereby reducing the two reconstruction problems into one. This innovative approach has several advantages over conventional approaches in which PACT and USCT images are reconstructed independently: (1) Variations in the SOS will automatically be accounted for, optimizing PACT image quality; (2) The reconstructed PACT and USCT images will possess minimal systematic artifacts because errors in the imaging models will be optimally balanced during the joint reconstruction; (3) Due to the exploitation of information regarding the SOS distribution in the full-view PACT data, our approach will permit high-resolution reconstruction of the SOS distribution from sparse array data.

  7. Hybrid µCT-FMT imaging and image analysis

    PubMed Central

    Zafarnia, Sara; Babler, Anne; Jahnen-Dechent, Willi; Lammers, Twan; Lederle, Wiltrud; Kiessling, Fabian

    2015-01-01

    Fluorescence-mediated tomography (FMT) enables longitudinal and quantitative determination of the fluorescence distribution in vivo and can be used to assess the biodistribution of novel probes and to assess disease progression using established molecular probes or reporter genes. The combination with an anatomical modality, e.g., micro computed tomography (µCT), is beneficial for image analysis and for fluorescence reconstruction. We describe a protocol for multimodal µCT-FMT imaging including the image processing steps necessary to extract quantitative measurements. After preparing the mice and performing the imaging, the multimodal data sets are registered. Subsequently, an improved fluorescence reconstruction is performed, which takes into account the shape of the mouse. For quantitative analysis, organ segmentations are generated based on the anatomical data using our interactive segmentation tool. Finally, the biodistribution curves are generated using a batch-processing feature. We show the applicability of the method by assessing the biodistribution of a well-known probe that binds to bones and joints. PMID:26066033

  8. Improving best-phase image quality in cardiac CT by motion correction with MAM optimization

    SciTech Connect

    Rohkohl, Christopher; Bruder, Herbert; Stierstorfer, Karl; Flohr, Thomas

    2013-03-15

    Purpose: Research in image reconstruction for cardiac CT aims at using motion correction algorithms to improve the image quality of the coronary arteries. The key to those algorithms is motion estimation, which is currently based on 3-D/3-D registration to align the structures of interest in images acquired in multiple heart phases. The need for an extended scan data range covering several heart phases is critical in terms of radiation dose to the patient and limits the clinical potential of the method. Furthermore, literature reports only slight quality improvements of the motion corrected images when compared to the most quiet phase (best-phase) that was actually used for motion estimation. In this paper a motion estimation algorithm is proposed which does not require an extended scan range but works with a short scan data interval, and which markedly improves the best-phase image quality. Methods: Motion estimation is based on the definition of motion artifact metrics (MAM) to quantify motion artifacts in a 3-D reconstructed image volume. The authors use two different MAMs, entropy, and positivity. By adjusting the motion field parameters, the MAM of the resulting motion-compensated reconstruction is optimized using a gradient descent procedure. In this way motion artifacts are minimized. For a fast and practical implementation, only analytical methods are used for motion estimation and compensation. Both the MAM-optimization and a 3-D/3-D registration-based motion estimation algorithm were investigated by means of a computer-simulated vessel with a cardiac motion profile. Image quality was evaluated using normalized cross-correlation (NCC) with the ground truth template and root-mean-square deviation (RMSD). Four coronary CT angiography patient cases were reconstructed to evaluate the clinical performance of the proposed method. Results: For the MAM-approach, the best-phase image quality could be improved for all investigated heart phases, with a maximum

  9. Cardiac Multidetector Computed Tomography: Basic Physics of Image Acquisition and Clinical Applications

    PubMed Central

    Bardo, Dianna M.E; Brown, Paul

    2008-01-01

    Cardiac MDCT is here to stay. And, it is more than just imaging coronary arteries. Understanding the differences in and the benefits of one CT scanner from another will help you to optimize the capabilities of the scanner, but requires a basic understanding of the MDCT imaging physics. This review provides key information needed to understand the differences in the types of MDCT scanners, from 64 – 320 detectors, flat panels, single and dual source configurations, step and shoot prospective and retrospective gating, and how each factor influences radiation dose, spatial and temporal resolution, and image noise. PMID:19936200

  10. Nanoparticles as magnetic resonance imaging contrast agents for vascular and cardiac diseases

    PubMed Central

    Chen, Wei; Cormode, David P.; Fayad, Zahi A.; Mulder, Willem J. M.

    2011-01-01

    Advances in nanoparticle contrast agents for molecular imaging have made magnetic resonance imaging a promising modality for noninvasive visualization and assessment of vascular and cardiac disease processes. This review provides a description of the various nanoparticles exploited for imaging cardiovascular targets. Nanoparticle probes detecting inflammation, apoptosis, extracellular matrix, and angiogenesis may provide tools for assessing the risk of progressive vascular dysfunction and heart failure. The utility of nanoparticles as multimodal probes and/or theranostic agents has also been investigated. Although clinical application of these nanoparticles is largely unexplored, the potential for enhancing disease diagnosis and treatment is considerable. PMID:20967875

  11. Cardiac imaging of congenital heart diseases during interventional procedures continues to evolve: Pros and cons of the main techniques.

    PubMed

    Hascoët, Sebastien; Warin-Fresse, Karine; Baruteau, Alban-Elouen; Hadeed, Khaled; Karsenty, Clement; Petit, Jérôme; Guérin, Patrice; Fraisse, Alain; Acar, Philippe

    2016-02-01

    Cardiac catheterization has contributed to the progress made in the management of patients with congenital heart disease (CHD). First, it allowed clarification of the diagnostic assessment of CHD, by offering a better understanding of normal cardiac physiology and the pathophysiology and anatomy of complex malformations. Then, it became an alternative to surgery and a major component of the therapeutic approach for some CHD lesions. Nowadays, techniques have evolved and cardiac catheterization is widely used to percutaneously close intracardiac shunts, to relieve obstructive valvar or vessel lesions, and for transcatheter valve replacement. Accurate imaging is mandatory to guide these procedures. Cardiac imaging during catheterization of CHD must provide accurate images of lesions, surrounding cardiac structures, medical devices and tools used to deliver them. Cardiac imaging has to be 'real-time' with an excellent temporal resolution to ensure 'eyes-hands' synchronization and 'device-target area' accurate positioning. In this comprehensive review, we provide an overview of conventional cardiac imaging tools used in the catheterization laboratory in daily practice, as well as the effect of recent evolution and future imaging modalities. PMID:26858142

  12. Higher-Order Motion-Compensation for In Vivo Cardiac Diffusion Tensor Imaging in Rats

    PubMed Central

    Welsh, Christopher L.; DiBella, Edward V. R.; Hsu, Edward W.

    2015-01-01

    Motion of the heart has complicated in vivo applications of cardiac diffusion MRI and diffusion tensor imaging (DTI), especially in small animals such as rats where ultra-high-performance gradient sets are currently not available. Even with velocity compensation via, for example, bipolar encoding pulses, the variable shot-to-shot residual motion-induced spin phase can still give rise to pronounced artifacts. This study presents diffusion-encoding schemes that are designed to compensate for higher-order motion components, including acceleration and jerk, which also have the desirable practical features of minimal TEs and high achievable b-values. The effectiveness of these schemes was verified numerically on a realistic beating heart phantom, and demonstrated empirically with in vivo cardiac diffusion MRI in rats. Compensation for acceleration, and lower motion components, was found to be both necessary and sufficient for obtaining diffusion-weighted images of acceptable quality and SNR, which yielded the first in vivo cardiac DTI demonstrated in the rat. These findings suggest that compensation for higher order motion, particularly acceleration, can be an effective alternative solution to high-performance gradient hardware for improving in vivo cardiac DTI. PMID:25775486

  13. Current artefacts in cardiac and chest magnetic resonance imaging: tips and tricks.

    PubMed

    Alfudhili, Khalid; Masci, Pier G; Delacoste, Jean; Ledoux, Jean-B; Berchier, Grégoire; Dunet, Vincent; Qanadli, Salah D; Schwitter, Juerg; Beigelman-Aubry, Catherine

    2016-06-01

    Currently MRI is extensively used for the evaluation of cardiovascular and thoracic disorders because of the well-established advantages that include use of non-ionizing radiation, good contrast and high spatial resolution. Despite the advantages of this technique, numerous categories of artefacts are frequently encountered. They may be related to the scanner hardware or software functionalities, environmental factors or the human body itself. In particular, some artefacts may be exacerbated with high-field-strength MR machines (e.g. 3 T). Cardiac imaging poses specific challenges with respect to breath-holding and cardiac motion. In addition, new cardiac MR-conditional devices may also be responsible for peculiar artefacts. The image quality may thus be impaired and give rise to a misdiagnosis. Knowledge of acquisition and reconstruction techniques is required to understand and recognize the nature of these artefacts. This article will focus on the origin and appearance of the most common artefacts encountered in cardiac and chest MRI along with possible correcting methods to avoid or reduce them. PMID:26986460

  14. The clinical utility of new cardiac imaging modalities in Australasian clinical practice.

    PubMed

    Hamilton-Craig, Christian; Chan, Jonathan

    2016-08-01

    Cardiac imaging is a rapidly evolving field, with improvements in the diagnostic capabilities of non-invasive cardiac assessment. We review the two main emerging technologies in cardiac imaging: computed tomography coronary angiography (CTCA) to evaluate chest symptoms and to exclude coronary artery disease; and cardiovascular magnetic resonance (CMR) for evaluating cardiac morphology, function and presence of scar. CTCA is an excellent "rule out" test, with a negative predictive value approaching 100%. Radiation exposure is no longer a concern for CTCA, with doses routinely < 5 mSv, and as low as < 1 mSv in selected patients. CTCA is useful for excluding coronary artery disease, investigating the anatomy of coronary anomalies or fistulae, and for the patency of coronary bypass grafts. CMR is the reference test for the accurate quantitation of left ventricular and right ventricular size and function. CMR has no ionising radiation, making it particularly suitable for patients with heart failure or congenital heart disease who require longitudinal follow-up. Evaluation of cardiomyopathies (hypertrophic, ischaemic, infiltrative, myocarditis, iron overload or idiopathic) is a unique strength of CMR. Stress perfusion CMR has a strong evidence base and improved spatial and temporal resolution compared with nuclear single-photon emission computed tomography. PMID:27465770

  15. The clinical utility of new cardiac imaging modalities in Australasian clinical practice.

    PubMed

    Hamilton-Craig, Christian; Chan, Jonathan

    2016-08-01

    Cardiac imaging is a rapidly evolving field, with improvements in the diagnostic capabilities of non-invasive cardiac assessment. We review the two main emerging technologies in cardiac imaging: computed tomography coronary angiography (CTCA) to evaluate chest symptoms and to exclude coronary artery disease; and cardiovascular magnetic resonance (CMR) for evaluating cardiac morphology, function and presence of scar. CTCA is an excellent "rule out" test, with a negative predictive value approaching 100%. Radiation exposure is no longer a concern for CTCA, with doses routinely < 5 mSv, and as low as < 1 mSv in selected patients. CTCA is useful for excluding coronary artery disease, investigating the anatomy of coronary anomalies or fistulae, and for the patency of coronary bypass grafts. CMR is the reference test for the accurate quantitation of left ventricular and right ventricular size and function. CMR has no ionising radiation, making it particularly suitable for patients with heart failure or congenital heart disease who require longitudinal follow-up. Evaluation of cardiomyopathies (hypertrophic, ischaemic, infiltrative, myocarditis, iron overload or idiopathic) is a unique strength of CMR. Stress perfusion CMR has a strong evidence base and improved spatial and temporal resolution compared with nuclear single-photon emission computed tomography.

  16. Do imaging studies performed in physician offices increase downstream utilization? An empiric analysis of cardiac stress testing with imaging

    PubMed Central

    Chen, Jersey; Fazel, Reza; Ross, Joseph S.; McNamara, Robert L.; Einstein, Andrew J.; Al-Mallah, Mouaz; Krumholz, Harlan M.; Nallamothu, Brahmajee K.

    2012-01-01

    Objective To compare patterns of downstream testing and procedures after stress testing with imaging performed at physician offices versus at hospital-outpatient facilities. Background Stress testing with imaging has grown dramatically in recent years, but whether the location of where the test is performed correlates with different patterns for subsequent cardiac testing and procedures is unknown. Methods We identified 82,178 adults with private health insurance from 2005–2007 who underwent ambulatory myocardial perfusion imaging (MPI) or stress echocardiography (SE). Subsequent MPI, SE, cardiac catheterization or revascularization within 6 months were compared between physician office and hospital-outpatient settings. Results Overall, 84.5% of MPI and 84.9% of SE were performed in physician offices. The proportion of patients who underwent subsequent MPI, SE or cardiac catheterization was not statistically different between physician office and hospital-outpatient settings for MPI (14.2% v 14.1%, p=0.80) or SE (7.9% v 8.6%, p=0.21). However, patients with physician-office imaging had slightly higher rates of repeat MPI within 6 months compared with hospital-outpatient imaging for both index MPI (3.5% v 2.0%, p<0.001) and SE (3.4% v 2.1%, p<0.001), and slightly lower rates of cardiac catheterization after index MPI (11.5% v 12.3, p=0.01) and SE (4.5% v 7.0%, p<0.001). Differences in 6-month utilization were observed across the 5 healthcare markets after index MPI but not after index SE. Conclusions Physician office imaging is associated with slightly higher repeat MPI and fewer cardiac catheterizations than hospital outpatient imaging, but no overall difference in the proportion of patients undergoing additional further testing or procedures. While regional variation exists, especially for MPI, the relationship between physician-office location of stress testing with imaging and greater downstream resource utilization appears modest. PMID:21679898

  17. Comparison of simultaneous and sequential SPECT imaging for discrimination tasks in assessment of cardiac defects

    NASA Astrophysics Data System (ADS)

    Trott, C. M.; Ouyang, J.; El Fakhri, G.

    2010-11-01

    Simultaneous rest perfusion/fatty-acid metabolism studies have the potential to replace sequential rest/stress perfusion studies for the assessment of cardiac function. Simultaneous acquisition has the benefits of increased signal and lack of need for patient stress, but is complicated by cross-talk between the two radionuclide signals. We consider a simultaneous rest 99mTc-sestamibi/123I-BMIPP imaging protocol in place of the commonly used sequential rest/stress 99mTc-sestamibi protocol. The theoretical precision with which the severity of a cardiac defect and the transmural extent of infarct can be measured is computed for simultaneous and sequential SPECT imaging, and their performance is compared for discriminating (1) degrees of defect severity and (2) sub-endocardial from transmural defects. We consider cardiac infarcts for which reduced perfusion and metabolism are observed. From an information perspective, simultaneous imaging is found to yield comparable or improved performance compared with sequential imaging for discriminating both severity of defect and transmural extent of infarct, for three defects of differing location and size.

  18. Fully automated segmentation of left ventricle using dual dynamic programming in cardiac cine MR images

    NASA Astrophysics Data System (ADS)

    Jiang, Luan; Ling, Shan; Li, Qiang

    2016-03-01

    Cardiovascular diseases are becoming a leading cause of death all over the world. The cardiac function could be evaluated by global and regional parameters of left ventricle (LV) of the heart. The purpose of this study is to develop and evaluate a fully automated scheme for segmentation of LV in short axis cardiac cine MR images. Our fully automated method consists of three major steps, i.e., LV localization, LV segmentation at end-diastolic phase, and LV segmentation propagation to the other phases. First, the maximum intensity projection image along the time phases of the midventricular slice, located at the center of the image, was calculated to locate the region of interest of LV. Based on the mean intensity of the roughly segmented blood pool in the midventricular slice at each phase, end-diastolic (ED) and end-systolic (ES) phases were determined. Second, the endocardial and epicardial boundaries of LV of each slice at ED phase were synchronously delineated by use of a dual dynamic programming technique. The external costs of the endocardial and epicardial boundaries were defined with the gradient values obtained from the original and enhanced images, respectively. Finally, with the advantages of the continuity of the boundaries of LV across adjacent phases, we propagated the LV segmentation from the ED phase to the other phases by use of dual dynamic programming technique. The preliminary results on 9 clinical cardiac cine MR cases show that the proposed method can obtain accurate segmentation of LV based on subjective evaluation.

  19. Imaging Techniques in Percutaneous Cardiac Structural Interventions: Atrial Septal Defect Closure and Left Atrial Appendage Occlusion.

    PubMed

    Rodríguez Fernández, Antonio; Bethencourt González, Armando

    2016-08-01

    Because of advances in cardiac structural interventional procedures, imaging techniques are playing an increasingly important role. Imaging studies show sufficient anatomic detail of the heart structure to achieve an excellent outcome in interventional procedures. Up to 98% of atrial septal defects at the ostium secundum can be closed successfully with a percutaneous procedure. Candidates for this type of procedure can be identified through a systematic assessment of atrial septum anatomy, locating and measuring the size and shape of all defects, their rims, and the degree and direction of shunting. Three dimensional echocardiography has significantly improved anatomic assessments and the end result itself. In the future, when combined with other imaging techniques such as cardiac computed tomography and fluoroscopy, 3-dimensional echocardiography will be particularly useful for procedure guidance. Percutaneous closure of the left atrial appendage offers an alternative for treating patients with atrial fibrillation and contraindication for oral anticoagulants. In the future, the clinical focus may well turn to stroke prevention in selected patients. Percutaneous closure is effective and safe; device implantation is successful in 94% to 99% of procedures. However, the procedure requires an experienced cardiac structural interventional team. At present, 3-dimensional echocardiography is the most appropriate imaging technique to assess anatomy suitability, select device type and size, guide the procedure alongside fluoroscopy, and to follow-up the patient afterwards.

  20. Imaging Techniques in Percutaneous Cardiac Structural Interventions: Atrial Septal Defect Closure and Left Atrial Appendage Occlusion.

    PubMed

    Rodríguez Fernández, Antonio; Bethencourt González, Armando

    2016-08-01

    Because of advances in cardiac structural interventional procedures, imaging techniques are playing an increasingly important role. Imaging studies show sufficient anatomic detail of the heart structure to achieve an excellent outcome in interventional procedures. Up to 98% of atrial septal defects at the ostium secundum can be closed successfully with a percutaneous procedure. Candidates for this type of procedure can be identified through a systematic assessment of atrial septum anatomy, locating and measuring the size and shape of all defects, their rims, and the degree and direction of shunting. Three dimensional echocardiography has significantly improved anatomic assessments and the end result itself. In the future, when combined with other imaging techniques such as cardiac computed tomography and fluoroscopy, 3-dimensional echocardiography will be particularly useful for procedure guidance. Percutaneous closure of the left atrial appendage offers an alternative for treating patients with atrial fibrillation and contraindication for oral anticoagulants. In the future, the clinical focus may well turn to stroke prevention in selected patients. Percutaneous closure is effective and safe; device implantation is successful in 94% to 99% of procedures. However, the procedure requires an experienced cardiac structural interventional team. At present, 3-dimensional echocardiography is the most appropriate imaging technique to assess anatomy suitability, select device type and size, guide the procedure alongside fluoroscopy, and to follow-up the patient afterwards. PMID:27354151

  1. Four-dimensional modeling of the heart for image guidance of minimally invasive cardiac surgeries

    NASA Astrophysics Data System (ADS)

    Wierzbicki, Marcin; Drangova, Maria; Guiraudon, Gerard; Peters, Terry

    2004-05-01

    Minimally invasive surgery of the beating heart can be associated with two major limitations: selecting port locations for optimal target coverage from x-rays and angiograms, and navigating instruments in a dynamic and confined 3D environment using only an endoscope. To supplement the current surgery planning and guidance strategies, we continue developing VCSP - a virtual reality, patient-specific, thoracic cavity model derived from 3D pre-procedural images. In this work, we apply elastic image registration to 4D cardiac images to model the dynamic heart. Our method is validated on two image modalities, and for different parts of the cardiac anatomy. In a helical CT dataset of an excised heart phantom, we found that the artificial motion of the epicardial surface can be extracted to within 0.93 +/- 0.33 mm. For an MR dataset of a human volunteer, the error for different heart structures such as the myocardium, right and left atria, right ventricle, aorta, vena cava, and pulmonary artery, ranged from 1.08 +/- 0.18 mm to 1.14 +/- 0.22 mm. These results indicate that our method of modeling the motion of the heart is not only easily adaptable but also sufficiently accurate to meet the requirements for reliable cardiac surgery training, planning, and guidance.

  2. Hybrid PET/MR Imaging and Brain Connectivity

    PubMed Central

    Aiello, Marco; Cavaliere, Carlo; Salvatore, Marco

    2016-01-01

    In recent years, brain connectivity is gaining ever-increasing interest from the interdisciplinary research community. The study of brain connectivity is characterized by a multifaceted approach providing both structural and functional evidence of the relationship between cerebral regions at different scales. Although magnetic resonance (MR) is the most established imaging modality for investigating connectivity in vivo, the recent advent of hybrid positron emission tomography (PET)/MR scanners paved the way for more comprehensive investigation of brain organization and physiology. Due to the high sensitivity and biochemical specificity of radiotracers, combining MR with PET imaging may enrich our ability to investigate connectivity by introducing the concept of metabolic connectivity and cometomics and promoting new insights on the physiological and molecular bases underlying high-level neural organization. This review aims to describe and summarize the main methods of analysis of brain connectivity employed in MR imaging and nuclear medicine. Moreover, it will discuss practical aspects and state-of-the-art techniques for exploiting hybrid PET/MR imaging to investigate the relationship of physiological processes and brain connectivity. PMID:26973446

  3. Hybrid PET/MR Imaging and Brain Connectivity.

    PubMed

    Aiello, Marco; Cavaliere, Carlo; Salvatore, Marco

    2016-01-01

    In recent years, brain connectivity is gaining ever-increasing interest from the interdisciplinary research community. The study of brain connectivity is characterized by a multifaceted approach providing both structural and functional evidence of the relationship between cerebral regions at different scales. Although magnetic resonance (MR) is the most established imaging modality for investigating connectivity in vivo, the recent advent of hybrid positron emission tomography (PET)/MR scanners paved the way for more comprehensive investigation of brain organization and physiology. Due to the high sensitivity and biochemical specificity of radiotracers, combining MR with PET imaging may enrich our ability to investigate connectivity by introducing the concept of metabolic connectivity and cometomics and promoting new insights on the physiological and molecular bases underlying high-level neural organization. This review aims to describe and summarize the main methods of analysis of brain connectivity employed in MR imaging and nuclear medicine. Moreover, it will discuss practical aspects and state-of-the-art techniques for exploiting hybrid PET/MR imaging to investigate the relationship of physiological processes and brain connectivity. PMID:26973446

  4. Hybrid tenso-vectorial compressive sensing for hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Li, Qun; Bernal, Edgar A.

    2016-05-01

    Hyperspectral imaging has a wide range of applications relying on remote material identification, including astronomy, mineralogy, and agriculture; however, due to the large volume of data involved, the complexity and cost of hyperspectral imagers can be prohibitive. The exploitation of redundancies along the spatial and spectral dimensions of a hyperspectral image of a scene has created new paradigms that overcome the limitations of traditional imaging systems. While compressive sensing (CS) approaches have been proposed and simulated with success on already acquired hyperspectral imagery, most of the existing work relies on the capability to simultaneously measure the spatial and spectral dimensions of the hyperspectral cube. Most real-life devices, however, are limited to sampling one or two dimensions at a time, which renders a significant portion of the existing work unfeasible. We propose a new variant of the recently proposed serial hybrid vectorial and tensorial compressive sensing (HCS-S) algorithm that, like its predecessor, is compatible with real-life devices both in terms of the acquisition and reconstruction requirements. The newly introduced approach is parallelizable, and we abbreviate it as HCS-P. Together, HCS-S and HCS-P comprise a generalized framework for hybrid tenso-vectorial compressive sensing, or HCS for short. We perform a detailed analysis that demonstrates the uniqueness of the signal reconstructed by both the original HCS-S and the proposed HCS-P algorithms. Last, we analyze the behavior of the HCS reconstruction algorithms in the presence of measurement noise, both theoretically and experimentally.

  5. Murine cardiac images obtained with focusing pinhole SPECT are barely influenced by extra-cardiac activity

    NASA Astrophysics Data System (ADS)

    Branderhorst, Woutjan; van der Have, Frans; Vastenhouw, Brendan; Viergever, Max A.; Beekman, Freek J.

    2012-02-01

    Ultra-high-resolution SPECT images can be obtained with focused multipinhole collimators. Here we investigate the influence of unwanted high tracer uptake outside the scan volume on reconstructed tracer distributions inside the scan volume, for 99mTc-tetrofosmin myocardial perfusion scanning in mice. Simulated projections of a digital mouse phantom (MOBY) in a focusing multipinhole SPECT system (U-SPECT-II, MILabs, The Netherlands) were generated. With this system differently sized user-defined scan volumes can be selected, by translating the animal in 3D through the focusing collimators. Scan volume selections were set to (i) a minimal volume containing just the heart, acquired without translating the animal during scanning, (ii) a slightly larger scan volume as is typically applied for the heart, requiring only small XYZ translations during scanning, (iii) same as (ii), but extended further transaxially, and (iv) same as (ii), but extended transaxially to cover the full thorax width (gold standard). Despite an overall negative bias that is significant for the minimal scan volume, all selected volumes resulted in visually similar images. Quantitative differences in the reconstructed myocardium between gold standard and the results from the smaller scan volume selections were small; the 17 standardized myocardial segments of a bull's eye plot, normalized to the myocardial mean of the gold standard, deviated on average 6.0%, 2.5% and 1.9% for respectively the minimal, the typical and the extended scan volume, while maximum absolute deviations were respectively 18.6%, 9.0% and 5.2%. Averaged over ten low-count noisy simulations, the mean absolute deviations were respectively 7.9%, 3.2% and 1.9%. In low-count noisy simulations, the mean and maximum absolute deviations for the minimal scan volume could be reduced to respectively 4.2% and 12.5% by performing a short survey scan of the exterior activity and focusing the remaining scan time at the organ of interest. We

  6. Image artefact propagation in motion estimation and reconstruction in interventional cardiac C-arm CT.

    PubMed

    Müller, K; Maier, A K; Schwemmer, C; Lauritsch, G; De Buck, S; Wielandts, J-Y; Hornegger, J; Fahrig, R

    2014-06-21

    The acquisition of data for cardiac imaging using a C-arm computed tomography system requires several seconds and multiple heartbeats. Hence, incorporation of motion correction in the reconstruction step may improve the resulting image quality. Cardiac motion can be estimated by deformable three-dimensional (3D)/3D registration performed on initial 3D images of different heart phases. This motion information can be used for a motion-compensated reconstruction allowing the use of all acquired data for image reconstruction. However, the result of the registration procedure and hence the estimated deformations are influenced by the quality of the initial 3D images. In this paper, the sensitivity of the 3D/3D registration step to the image quality of the initial images is studied. Different reconstruction algorithms are evaluated for a recently proposed cardiac C-arm CT acquisition protocol. The initial 3D images are all based on retrospective electrocardiogram (ECG)-gated data. ECG-gating of data from a single C-arm rotation provides only a few projections per heart phase for image reconstruction. This view sparsity leads to prominent streak artefacts and a poor signal to noise ratio. Five different initial image reconstructions are evaluated: (1) cone beam filtered-backprojection (FDK), (2) cone beam filtered-backprojection and an additional bilateral filter (FFDK), (3) removal of the shadow of dense objects (catheter, pacing electrode, etc) before reconstruction with a cone beam filtered-backprojection (cathFDK), (4) removal of the shadow of dense objects before reconstruction with a cone beam filtered-backprojection and a bilateral filter (cathFFDK). The last method (5) is an iterative few-view reconstruction (FV), the prior image constrained compressed sensing combined with the improved total variation algorithm. All reconstructions are investigated with respect to the final motion-compensated reconstruction quality. The algorithms were tested on a mathematical

  7. Image artefact propagation in motion estimation and reconstruction in interventional cardiac C-arm CT

    NASA Astrophysics Data System (ADS)

    Müller, K.; Maier, A. K.; Schwemmer, C.; Lauritsch, G.; De Buck, S.; Wielandts, J.-Y.; Hornegger, J.; Fahrig, R.

    2014-06-01

    The acquisition of data for cardiac imaging using a C-arm computed tomography system requires several seconds and multiple heartbeats. Hence, incorporation of motion correction in the reconstruction step may improve the resulting image quality. Cardiac motion can be estimated by deformable three-dimensional (3D)/3D registration performed on initial 3D images of different heart phases. This motion information can be used for a motion-compensated reconstruction allowing the use of all acquired data for image reconstruction. However, the result of the registration procedure and hence the estimated deformations are influenced by the quality of the initial 3D images. In this paper, the sensitivity of the 3D/3D registration step to the image quality of the initial images is studied. Different reconstruction algorithms are evaluated for a recently proposed cardiac C-arm CT acquisition protocol. The initial 3D images are all based on retrospective electrocardiogram (ECG)-gated data. ECG-gating of data from a single C-arm rotation provides only a few projections per heart phase for image reconstruction. This view sparsity leads to prominent streak artefacts and a poor signal to noise ratio. Five different initial image reconstructions are evaluated: (1) cone beam filtered-backprojection (FDK), (2) cone beam filtered-backprojection and an additional bilateral filter (FFDK), (3) removal of the shadow of dense objects (catheter, pacing electrode, etc) before reconstruction with a cone beam filtered-backprojection (cathFDK), (4) removal of the shadow of dense objects before reconstruction with a cone beam filtered-backprojection and a bilateral filter (cathFFDK). The last method (5) is an iterative few-view reconstruction (FV), the prior image constrained compressed sensing combined with the improved total variation algorithm. All reconstructions are investigated with respect to the final motion-compensated reconstruction quality. The algorithms were tested on a mathematical

  8. Delayed Myocardial Enhancement in Cardiac Magnetic Resonance Imaging

    PubMed Central

    Franco, Arie; Javidi, Saeed; Ruehm, Stefan G

    2015-01-01

    Delayed myocardial enhancement MRI is a highly valuable but non-specific imaging technique that is ancillary in the diagnosis of a variety of diseases including myocardial viability, cardiomyopathy, myocarditis and other infiltrative myocardial processes. The lack of specificity stems from the wide variety of differential diagnoses that may present with overlapping patterns of delayed enhancement. Many of these differential diagnoses have been presented and discussed in this article. PMID:26622933

  9. Nuclear cardiac imaging for the assessment of myocardial viability

    PubMed Central

    Slart, R.H.J.A.; Bax, J.J.; van der Wall, E.E.; van Veldhuisen, D.J.; Jager, P.L.; Dierckx, R.A.

    2005-01-01

    An important aspect of the diagnostic and prognostic work-up of patients with ischaemic cardiomyopathy is the assessment of myocardial viability. Patients with left ventricular dysfunction who have viable myocardium are the patients at highest risk because of the potential for ischaemia but at the same time benefit most from revascularisation. It is important to identify viable myocardium in these patients, and radionuclide myocardial scintigraphy is an excellent tool for this. Single-photon emission computed tomography perfusion scintigraphy (SPECT), whether using 201thallium, 99mTc-sestamibi, or 99mTc- tetrofosmin, in stress and/or rest protocols, has consistently been shown to be an effective modality for identifying myocardial viability and guiding appropriate management. Metabolic and perfusion imaging with positron emission tomography radiotracers frequently adds additional information and is a powerful tool for predicting which patients will have an improved outcome from revascularisation. New techniques in the nuclear cardiology field, such as attenuation corrected SPECT, dual isotope simultaneous acquisition (DISA) SPECT and gated FDG PET are promising and will further improve the detection of myocardial viability. Also the combination of multislice computed tomography scanners with PET opens possibilities of adding coronary calcium scoring and noninvasive coronary angiography to myocardial perfusion imaging and quantification. ImagesFigure 1Figure 2Figure 3 PMID:25696432

  10. Intraoperative IR imaging in the cardiac operating room

    NASA Astrophysics Data System (ADS)

    Szabo, Tamas; Fazekas, Levente; Horkay, Ferenc; Geller, Laslu; Gyongy, Tibor; Juhasz-Nagy, Alexander

    1999-07-01

    The high blood flow rate and the considerable metabolic activity render the myocardium a possible candidate for IR imaging. The study was aimed to test cardiothermography in evaluating arterial bypass graft patency and in assessing myocardial protection during open-heart surgery. Ten patients underwent arterial bypass grafting. Thermograms were obtained immediately before and after opening the grafts. As the bypasses were opened in hypothermia the warmer blood coming from the extracorporeal circulation readily delineated graft and coronary anatomy. By the end of the 5 min observation period, the revascularized area exhibited a temperature increase of 5.9 +/- 0.7 degrees C. The affectivity of antegrade cardioplegia was monitored in 38 patients undergoing either valve implantations or aorto- coronary bypass surgery. Thermographic imags were taken after sternotomy, before aortic cross-clamping and after administrating the 4 degrees C cardioplegic solution. Most of the patients displayed adequate myocardial cooling, moreover the bypass-group exhibited a more profound temperature-decrease. In conclusion, cardiothermography can visualize arterial grafts, recipient coronaries and collaterals seconds after opening by bypass, thus it properly evaluated arterial bypass graft patency. The obtained images could easily be analyzed for qualitative flow- and quantitative temperature changes. Myocardial protection could also be safely assessed with thermography.

  11. Kalman filter techniques for accelerated Cartesian dynamic cardiac imaging.

    PubMed

    Feng, Xue; Salerno, Michael; Kramer, Christopher M; Meyer, Craig H

    2013-05-01

    In dynamic MRI, spatial and temporal parallel imaging can be exploited to reduce scan time. Real-time reconstruction enables immediate visualization during the scan. Commonly used view-sharing techniques suffer from limited temporal resolution, and many of the more advanced reconstruction methods are either retrospective, time-consuming, or both. A Kalman filter model capable of real-time reconstruction can be used to increase the spatial and temporal resolution in dynamic MRI reconstruction. The original study describing the use of the Kalman filter in dynamic MRI was limited to non-Cartesian trajectories because of a limitation intrinsic to the dynamic model used in that study. Here the limitation is overcome, and the model is applied to the more commonly used Cartesian trajectory with fast reconstruction. Furthermore, a combination of the Kalman filter model with Cartesian parallel imaging is presented to further increase the spatial and temporal resolution and signal-to-noise ratio. Simulations and experiments were conducted to demonstrate that the Kalman filter model can increase the temporal resolution of the image series compared with view-sharing techniques and decrease the spatial aliasing compared with TGRAPPA. The method requires relatively little computation, and thus is suitable for real-time reconstruction.

  12. Cardiac gating with a pulse oximeter for dual-energy imaging

    NASA Astrophysics Data System (ADS)

    Shkumat, N. A.; Siewerdsen, J. H.; Dhanantwari, A. C.; Williams, D. B.; Paul, N. S.; Yorkston, J.; Van Metter, R.

    2008-11-01

    The development and evaluation of a prototype cardiac gating system for double-shot dual-energy (DE) imaging is described. By acquiring both low- and high-kVp images during the resting phase of the cardiac cycle (diastole), heart misalignment between images can be reduced, thereby decreasing the magnitude of cardiac motion artifacts. For this initial implementation, a fingertip pulse oximeter was employed to measure the peripheral pulse waveform ('plethysmogram'), offering potential logistic, cost and workflow advantages compared to an electrocardiogram. A gating method was developed that accommodates temporal delays due to physiological pulse propagation, oximeter waveform processing and the imaging system (software, filter-wheel, anti-scatter Bucky-grid and flat-panel detector). Modeling the diastolic period allowed the calculation of an implemented delay, timp, required to trigger correctly during diastole at any patient heart rate (HR). The model suggests a triggering scheme characterized by two HR regimes, separated by a threshold, HRthresh. For rates at or below HRthresh, sufficient time exists to expose on the same heartbeat as the plethysmogram pulse [timp(HR) = 0]. Above HRthresh, a characteristic timp(HR) delays exposure to the subsequent heartbeat, accounting for all fixed and variable system delays. Performance was evaluated in terms of accuracy and precision of diastole-trigger coincidence and quantitative evaluation of artifact severity in gated and ungated DE images. Initial implementation indicated 85% accuracy in diastole-trigger coincidence. Through the identification of an improved HR estimation method (modified temporal smoothing of the oximeter waveform), trigger accuracy of 100% could be achieved with improved precision. To quantify the effect of the gating system on DE image quality, human observer tests were conducted to measure the magnitude of cardiac artifact under conditions of successful and unsuccessful diastolic gating. Six observers

  13. Gated cardiac scanning using limited-angle image reconstruction technique and information in the neighboring phases

    SciTech Connect

    Tam, K.C.; MacDonald, B.; Perez-Mendez, V.

    1984-02-01

    It is known that there are gaps in scan angle in gated cardiac scanning due to lack of synchronization between heart beat and CT machine rotation. The missing projections in these gaps result in artifacts in the reconstructed images. In a previous paper an iterative limited-angle reconstruction technique was employed to fill in the missing projections to remove the artifacts. It was found there that the root-mean-square errors of the limited-angle images were reduced to a level comparable to those of reconstructions using complete-angle information. In the present paper the results are further improved by using the scans of a neighboring portion of the cardiac cycle as a first estimate of the missing scans in the phase of interest when initializing the iterations. Such a modification provides a better starting point for the iterations.

  14. Myocardial Infarct Imaging of Antibodies to Canine Cardiac Myosin with Indium-111-Diethylenetriamine Pentaacetic Acid

    NASA Astrophysics Data System (ADS)

    Khaw, Ban An; Fallon, John T.; Strauss, H. William; Haber, Edgar

    1980-07-01

    Antibodies, by virtue of marked selectivity and affinity, may lend themselves to identification of structures of unique antigenic specificity in vivo. In experimental myocardial infarction in dogs, F(ab')2 fragments of antibodies to cardiac myosin that had been labeled with iodine-131 were shown to localize within the lesion. Because the energy characteristics of iodine isotopes are not ideal for imaging with a gamma camera, a new method for labeling antibody fragments with divalent or polyvalent radionuclides was developed. A bifunctional chelating agent, diethylenetriamine pentaacetic acid was covalently coupled, by an amide bond, to Fab fragments of antibodies to canine cardiac myosin. A stable chelate was then formed with indium-111, a nuclide that has appropriate half-life and energy characteristics for gamma imaging. Antibodies treated in this way retain their antigen-binding activity and are useful in locating myocardial infarcts in vivo.

  15. Myocardial infarct imaging of antibodies to canine cardiac myosin with indium-111-diethylenetriamine pentaacetic acid.

    PubMed

    Khaw, B A; Fallon, F T; Strauss, H W; Haber, E

    1980-07-11

    Antibodies, by virtue of marked selectivity and affinity, may lend themselves to identification of structures of unique antigenic specificity in vivo. In experimental myocardial infarction in dogs, F(ab')2 fragments of antibodies to cardiac myosin that had been labeled with iodine-131 were shown to localize within the lesion. Because the energy characteristics of iodine isotopes are not ideal for imaging with a gamma camera, a new method for labeling antibody fragments with divalent or polyvalent radionuclides was developed. A bifunctional chelating agent, diethylenetriamine pentaacetic acid was covalently coupled, by an amide bond, to Fab fragments of antibodies to canine cardiac myosin. A stable chelate was then formed with indium-111, a nuclide that has appropriate half-life and energy characteristics for gamma imaging. Antibodies treated in this way retain their antigen-binding activity and are useful in locating myocardial infarcts in vivo. PMID:7384803

  16. Hybrid Imaging for Patient-Specific Dosimetry in Radionuclide Therapy.

    PubMed

    Ljungberg, Michael; Gleisner, Katarina Sjögreen

    2015-01-01

    Radionuclide therapy aims to treat malignant diseases by systemic administration of radiopharmaceuticals, often using carrier molecules such as peptides and antibodies. The radionuclides used emit electrons or alpha particles as a consequence of radioactive decay, thus leading to local energy deposition. Administration to individual patients can be tailored with regards to the risk of toxicity in normal organs by using absorbed dose planning. The scintillation camera, employed in planar imaging or single-photon emission computed tomography (SPECT), generates images of the spatially and temporally varying activity distribution. Recent commercially available combined SPECT and computed tomography (CT) systems have dramatically increased the possibility of performing accurate dose planning by using the CT information in several steps of the dose-planning calculation chain. This paper discusses the dosimetry chain used for individual absorbed-dose planning and highlights the areas where hybrid imaging makes significant contributions. PMID:26854156

  17. Four-dimensional B-spline-based motion analysis of tagged cardiac MR images

    NASA Astrophysics Data System (ADS)

    Ozturk, Cengizhan; McVeigh, Elliot R.

    1999-05-01

    In recent years, with development of new MRI techniques, noninvasive evaluation of global and regional cardiac function is becoming a reality. One of the methods used for this purpose is MRI tagging. In tagging, spatially encoded magnetic saturation planes, tags, are created within tissues. These act as temporary markers and move with the tissue. In cardiac tagging, tag deformation pattern provides useful qualitative and quantitative information about the functional properties of underlying myocardium. The measured deformation of a single tag plane contains only unidirectional information of the past motion. In order to track the motion of a cardiac material point, this sparse, single dimensional data has to be combined with similar information gathered from other tag sets and all time frames. Previously, several methods have been developed which rely on the specific geometry of the chambers. Here, we employ an image plane based, simple cartesian coordinate system and provide a stepwise method to describe the heart motion using a four-dimensional tensor product of B-splines. The proposed displacement and forward motion fields exhibited sub-pixel accuracy. Since our motion fields are parametric and based on an image plane based coordinate system, trajectories or other derived values (velocity, acceleration, strains...) can be calculated for any desired point on the MRI images. This method is sufficiently general so that the motion of any tagged structure can be tracked.

  18. Myocardial Infarct Segmentation from Magnetic Resonance Images for Personalized Modeling of Cardiac Electrophysiology

    PubMed Central

    Ukwatta, Eranga; Arevalo, Hermenegild; Li, Kristina; Yuan, Jing; Qiu, Wu; Malamas, Peter; Wu, Katherine C.

    2016-01-01

    Accurate representation of myocardial infarct geometry is crucial to patient-specific computational modeling of the heart in ischemic cardiomyopathy. We have developed a methodology for segmentation of left ventricular (LV) infarct from clinically acquired, two-dimensional (2D), late-gadolinium enhanced cardiac magnetic resonance (LGE-CMR) images, for personalized modeling of ventricular electrophysiology. The infarct segmentation was expressed as a continuous min-cut optimization problem, which was solved using its dual formulation, the continuous max-flow (CMF). The optimization objective comprised of a smoothness term, and a data term that quantified the similarity between image intensity histograms of segmented regions and those of a set of training images. A manual segmentation of the LV myocardium was used to initialize and constrain the developed method. The three-dimensional geometry of infarct was reconstructed from its segmentation using an implicit, shape-based interpolation method. The proposed methodology was extensively evaluated using metrics based on geometry, and outcomes of individualized electrophysiological simulations of cardiac dys(function). Several existing LV infarct segmentation approaches were implemented, and compared with the proposed method. Our results demonstrated that the CMF method was more accurate than the existing approaches in reproducing expert manual LV infarct segmentations, and in electrophysiological simulations. The infarct segmentation method we have developed and comprehensively evaluated in this study constitutes an important step in advancing clinical applications of personalized simulations of cardiac electrophysiology. PMID:26731693

  19. Myocardial Infarct Segmentation From Magnetic Resonance Images for Personalized Modeling of Cardiac Electrophysiology.

    PubMed

    Ukwatta, Eranga; Arevalo, Hermenegild; Li, Kristina; Yuan, Jing; Qiu, Wu; Malamas, Peter; Wu, Katherine C; Trayanova, Natalia A; Vadakkumpadan, Fijoy

    2016-06-01

    Accurate representation of myocardial infarct geometry is crucial to patient-specific computational modeling of the heart in ischemic cardiomyopathy. We have developed a methodology for segmentation of left ventricular (LV) infarct from clinically acquired, two-dimensional (2D), late-gadolinium enhanced cardiac magnetic resonance (LGE-CMR) images, for personalized modeling of ventricular electrophysiology. The infarct segmentation was expressed as a continuous min-cut optimization problem, which was solved using its dual formulation, the continuous max-flow (CMF). The optimization objective comprised of a smoothness term, and a data term that quantified the similarity between image intensity histograms of segmented regions and those of a set of training images. A manual segmentation of the LV myocardium was used to initialize and constrain the developed method. The three-dimensional geometry of infarct was reconstructed from its segmentation using an implicit, shape-based interpolation method. The proposed methodology was extensively evaluated using metrics based on geometry, and outcomes of individualized electrophysiological simulations of cardiac dys(function). Several existing LV infarct segmentation approaches were implemented, and compared with the proposed method. Our results demonstrated that the CMF method was more accurate than the existing approaches in reproducing expert manual LV infarct segmentations, and in electrophysiological simulations. The infarct segmentation method we have developed and comprehensively evaluated in this study constitutes an important step in advancing clinical applications of personalized simulations of cardiac electrophysiology. PMID:26731693

  20. Cardiac diffusion tensor imaging based on compressed sensing using joint sparsity and low-rank approximation.

    PubMed

    Huang, Jianping; Wang, Lihui; Chu, Chunyu; Zhang, Yanli; Liu, Wanyu; Zhu, Yuemin

    2016-04-29

    Diffusion tensor magnetic resonance (DTMR) imaging and diffusion tensor imaging (DTI) have been widely used to probe noninvasively biological tissue structures. However, DTI suffers from long acquisition times, which limit its practical and clinical applications. This paper proposes a new Compressed Sensing (CS) reconstruction method that employs joint sparsity and rank deficiency to reconstruct cardiac DTMR images from undersampled k-space data. Diffusion-weighted images acquired in different diffusion directions were firstly stacked as columns to form the matrix. The matrix was row sparse in the transform domain and had a low rank. These two properties were then incorporated into the CS reconstruction framework. The underlying constrained optimization problem was finally solved by the first-order fast method. Experiments were carried out on both simulation and real human cardiac DTMR images. The results demonstrated that the proposed approach had lower reconstruction errors for DTI indices, including fractional anisotropy (FA) and mean diffusivities (MD), compared to the existing CS-DTMR image reconstruction techniques. PMID:27163322

  1. First pass cable artefact correction for cardiac C-arm CT imaging.

    PubMed

    Haase, C; Schäfer, D; Kim, M; Chen, S J; Carroll, J D; Eshuis, P; Dössel, O; Grass, M

    2014-07-21

    Cardiac C-arm CT imaging delivers a tomographic region-of-interest reconstruction of the patient's heart during image guided catheter interventions. Due to the limited size of the flat detector a volume image is reconstructed, which is truncated in the cone-beam (along the patient axis) and the fan-beam (in the transaxial plane) direction. To practically address this local tomography problem correction methods, like projection extension, are available for first pass image reconstruction. For second pass correction methods, like metal artefact reduction, alternative correction schemes are required when the field of view is limited to a region-of-interest of the patient. In classical CT imaging metal artefacts are corrected by metal identification in a first volume reconstruction and generation of a corrected projection data set followed by a second reconstruction. This approach fails when the metal structures are located outside the reconstruction field of view. When a C-arm CT is performed during a cardiac intervention pacing leads and other cables are frequently positioned on the patients skin, which results in propagating streak artefacts in the reconstruction volume. A first pass approach to reduce this type of artefact is introduced and evaluated here. It makes use of the fact that the projected position of objects outside the reconstruction volume changes with the projection perspective. It is shown that projection based identification, tracking and removal of high contrast structures like cables, only detected in a subset of the projections, delivers a more consistent reconstruction volume with reduced artefact level. The method is quantitatively evaluated based on 50 simulations using cardiac CT data sets with variable cable positioning. These data sets are forward projected using a C-arm CT system geometry and generate artefacts comparable to those observed in clinical cardiac C-arm CT acquisitions. A C-arm CT simulation of every cardiac CT data set without

  2. First pass cable artefact correction for cardiac C-arm CT imaging

    NASA Astrophysics Data System (ADS)

    Haase, C.; Schäfer, D.; Kim, M.; Chen, S. J.; Carroll, J. D.; Eshuis, P.; Dössel, O.; Grass, M.

    2014-07-01

    Cardiac C-arm CT imaging delivers a tomographic region-of-interest reconstruction of the patient's heart during image guided catheter interventions. Due to the limited size of the flat detector a volume image is reconstructed, which is truncated in the cone-beam (along the patient axis) and the fan-beam (in the transaxial plane) direction. To practically address this local tomography problem correction methods, like projection extension, are available for first pass image reconstruction. For second pass correction methods, like metal artefact reduction, alternative correction schemes are required when the field of view is limited to a region-of-interest of the patient. In classical CT imaging metal artefacts are corrected by metal identification in a first volume reconstruction and generation of a corrected projection data set followed by a second reconstruction. This approach fails when the metal structures are located outside the reconstruction field of view. When a C-arm CT is performed during a cardiac intervention pacing leads and other cables are frequently positioned on the patients skin, which results in propagating streak artefacts in the reconstruction volume. A first pass approach to reduce this type of artefact is introduced and evaluated here. It makes use of the fact that the projected position of objects outside the reconstruction volume changes with the projection perspective. It is shown that projection based identification, tracking and removal of high contrast structures like cables, only detected in a subset of the projections, delivers a more consistent reconstruction volume with reduced artefact level. The method is quantitatively evaluated based on 50 simulations using cardiac CT data sets with variable cable positioning. These data sets are forward projected using a C-arm CT system geometry and generate artefacts comparable to those observed in clinical cardiac C-arm CT acquisitions. A C-arm CT simulation of every cardiac CT data set without

  3. First pass cable artefact correction for cardiac C-arm CT imaging.

    PubMed

    Haase, C; Schäfer, D; Kim, M; Chen, S J; Carroll, J D; Eshuis, P; Dössel, O; Grass, M

    2014-07-21

    Cardiac C-arm CT imaging delivers a tomographic region-of-interest reconstruction of the patient's heart during image guided catheter interventions. Due to the limited size of the flat detector a volume image is reconstructed, which is truncated in the cone-beam (along the patient axis) and the fan-beam (in the transaxial plane) direction. To practically address this local tomography problem correction methods, like projection extension, are available for first pass image reconstruction. For second pass correction methods, like metal artefact reduction, alternative correction schemes are required when the field of view is limited to a region-of-interest of the patient. In classical CT imaging metal artefacts are corrected by metal identification in a first volume reconstruction and generation of a corrected projection data set followed by a second reconstruction. This approach fails when the metal structures are located outside the reconstruction field of view. When a C-arm CT is performed during a cardiac intervention pacing leads and other cables are frequently positioned on the patients skin, which results in propagating streak artefacts in the reconstruction volume. A first pass approach to reduce this type of artefact is introduced and evaluated here. It makes use of the fact that the projected position of objects outside the reconstruction volume changes with the projection perspective. It is shown that projection based identification, tracking and removal of high contrast structures like cables, only detected in a subset of the projections, delivers a more consistent reconstruction volume with reduced artefact level. The method is quantitatively evaluated based on 50 simulations using cardiac CT data sets with variable cable positioning. These data sets are forward projected using a C-arm CT system geometry and generate artefacts comparable to those observed in clinical cardiac C-arm CT acquisitions. A C-arm CT simulation of every cardiac CT data set without

  4. Evaluation of the use of multimodality skin markers for the registration of pre-procedure cardiac MR images and intra-procedure x-ray fluoroscopy images for image guided cardiac electrophysiology procedures

    NASA Astrophysics Data System (ADS)

    Rhode, Kawal; Ma, Yingliang; Chandrasena, Angela; King, Andrew; Gao, Gang; Chinchapatnam, Phani; Sermesant, Maxime; Hawkes, David; Schaeffter, Tobias; Gill, Jaswinder; Razavi, Reza

    2008-03-01

    This paper presents the evaluation of the use of multimodality skin markers for the registration of cardiac magnetic resonance (MR) image data to x-ray fluoroscopy data for the guidance of cardiac electrophysiology procedures. The approach was validated using a phantom study and 3 patients undergoing pulmonary vein (PV) isolation for the treatment of paroxysmal atrial fibrillation. In the patient study, skin markers were affixed to the patients' chest and used to register pre-procedure cardiac MR image data to intra-procedure fluoroscopy data. Registration errors were assessed using contrast angiograms of the left atrium that were available in 2 out of 3 cases. A clinical expert generated "gold standard" registrations by adjusting the registration manually. Target registration errors (TREs) were computed using points on the PV ostia. Ablation locations were computed using biplane x-ray imaging. Registration errors were further assessed by computing the distances of the ablation points to the registered left atrial surface for all 3 patients. The TREs were 6.0 & 3.1mm for patients 1 & 2. The mean ablation point errors were 6.2, 3.8, & 3.0mm for patients 1, 2, & 3. These results are encouraging in the context of a 5mm clinical accuracy requirement for this type of procedure. We conclude that multimodality skin markers have the potential to provide anatomical image integration for x-ray guided cardiac electrophysiology procedures, especially if coupled with an accurate respiratory motion compensation strategy.

  5. The benefit of personalized hybrid SPECT/CT pulmonary imaging.

    PubMed

    Simanek, Milan; Koranda, Pavel

    2016-01-01

    Hybrid pulmonary imaging in the present day has seen a fusion of various uses of CT scans, including angiography (CTAG), diagnostic CT, low dose CT (LDCT), and perfusion or ventilation scintigraphy in tomographic or planar imaging. Determining the most effective individualized test for the complete diagnostics of patients with pulmonary symptoms for various groups of patients is a major issue. The aim of the present study was to assess the effectiveness of the implementation of hybrid imaging in current methods of nuclear medicine in differential diagnostics of pulmonary embolism (PE). 326 patients were examined for symptomatology of PE. Patients were initially examined with SPECT perfusion scintigraphy. SPECT finding without sub-segmental or segmental defects was considered unproven PE but the finding of more segments or sub-segments in various lung parts was considered nearly proven PE. In the case of unclear findings, LDCT was added and in the case of a higher suspicion of PE, a ventilation examination was applied. It was possible to determine 83% of patients with the occurrence or exclusion of PE only on the basis of the perfusion SPECT examination and an X-ray or LDCT. LDCT was determined with 26% of the patients. With 41% of them, the use of LDCT resulted in an alternative diagnosis, explaining perfusion abnormalities. The research proved that use of SPECT/LDCT for differential diagnosis of lung symptoms brings about improvement in the diagnosis of pulmonary embolism or the identification of other lung diseases when lung perfusion abnormalities are recorded. PMID:27648373

  6. The benefit of personalized hybrid SPECT/CT pulmonary imaging

    PubMed Central

    Simanek, Milan; Koranda, Pavel

    2016-01-01

    Hybrid pulmonary imaging in the present day has seen a fusion of various uses of CT scans, including angiography (CTAG), diagnostic CT, low dose CT (LDCT), and perfusion or ventilation scintigraphy in tomographic or planar imaging. Determining the most effective individualized test for the complete diagnostics of patients with pulmonary symptoms for various groups of patients is a major issue. The aim of the present study was to assess the effectiveness of the implementation of hybrid imaging in current methods of nuclear medicine in differential diagnostics of pulmonary embolism (PE). 326 patients were examined for symptomatology of PE. Patients were initially examined with SPECT perfusion scintigraphy. SPECT finding without sub-segmental or segmental defects was considered unproven PE but the finding of more segments or sub-segments in various lung parts was considered nearly proven PE. In the case of unclear findings, LDCT was added and in the case of a higher suspicion of PE, a ventilation examination was applied. It was possible to determine 83% of patients with the occurrence or exclusion of PE only on the basis of the perfusion SPECT examination and an X-ray or LDCT. LDCT was determined with 26% of the patients. With 41% of them, the use of LDCT resulted in an alternative diagnosis, explaining perfusion abnormalities. The research proved that use of SPECT/LDCT for differential diagnosis of lung symptoms brings about improvement in the diagnosis of pulmonary embolism or the identification of other lung diseases when lung perfusion abnormalities are recorded.

  7. The benefit of personalized hybrid SPECT/CT pulmonary imaging

    PubMed Central

    Simanek, Milan; Koranda, Pavel

    2016-01-01

    Hybrid pulmonary imaging in the present day has seen a fusion of various uses of CT scans, including angiography (CTAG), diagnostic CT, low dose CT (LDCT), and perfusion or ventilation scintigraphy in tomographic or planar imaging. Determining the most effective individualized test for the complete diagnostics of patients with pulmonary symptoms for various groups of patients is a major issue. The aim of the present study was to assess the effectiveness of the implementation of hybrid imaging in current methods of nuclear medicine in differential diagnostics of pulmonary embolism (PE). 326 patients were examined for symptomatology of PE. Patients were initially examined with SPECT perfusion scintigraphy. SPECT finding without sub-segmental or segmental defects was considered unproven PE but the finding of more segments or sub-segments in various lung parts was considered nearly proven PE. In the case of unclear findings, LDCT was added and in the case of a higher suspicion of PE, a ventilation examination was applied. It was possible to determine 83% of patients with the occurrence or exclusion of PE only on the basis of the perfusion SPECT examination and an X-ray or LDCT. LDCT was determined with 26% of the patients. With 41% of them, the use of LDCT resulted in an alternative diagnosis, explaining perfusion abnormalities. The research proved that use of SPECT/LDCT for differential diagnosis of lung symptoms brings about improvement in the diagnosis of pulmonary embolism or the identification of other lung diseases when lung perfusion abnormalities are recorded. PMID:27648373

  8. Pseudo‐projection–driven, self‐gated cardiac cine imaging using cartesian golden step phase encoding

    PubMed Central

    Guo, Liheng; Derbyshire, J. Andrew

    2015-01-01

    Purpose To develop and evaluate a novel two‐dimensional self‐gated imaging technique for free‐breathing cardiac cine MRI that is free of motion‐detection overhead and requires minimal planning for motion tracking. Methods Motion along the readout direction was extracted solely from normal Cartesian imaging readouts near ky = 0. During imaging, the readouts below a certain |ky| threshold were scaled in magnitude and filtered in time to form “pseudo‐projections,” enabling projection‐based motion tracking along readout without frequently acquiring the central phase encode. A discrete golden step phase encode scheme allowed the |ky| threshold to be freely set after the scan while maintaining uniform motion sampling. Results The pseudo‐projections stream displayed sufficient spatiotemporal resolution for both cardiac and respiratory tracking, allowing retrospective reconstruction of free‐breathing non‐electrocardiogram (ECG) cines. The technique was tested on healthy subjects, and the resultant image quality, measured by blood‐myocardium boundary sharpness, myocardial mass, and single‐slice ejection fraction was found to be comparable to standard breath‐hold ECG‐gated cines. Conclusion The use of pseudo‐projections for motion tracking was found feasible for cardiorespiratory self‐gated imaging. Despite some sensitivity to flow and eddy currents, the simplicity of acquisition makes the proposed technique a valuable tool for self‐gated cardiac imaging. Magn Reson Med 76:417–429, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. PMID

  9. Fourier transform infrared spectroscopic imaging of cardiac tissue to detect collagen deposition after myocardial infarction

    NASA Astrophysics Data System (ADS)

    Cheheltani, Rabee; Rosano, Jenna M.; Wang, Bin; Sabri, Abdel Karim; Pleshko, Nancy; Kiani, Mohammad F.

    2012-05-01

    Myocardial infarction often leads to an increase in deposition of fibrillar collagen. Detection and characterization of this cardiac fibrosis is of great interest to investigators and clinicians. Motivated by the significant limitations of conventional staining techniques to visualize collagen deposition in cardiac tissue sections, we have developed a Fourier transform infrared imaging spectroscopy (FT-IRIS) methodology for collagen assessment. The infrared absorbance band centered at 1338 cm-1, which arises from collagen amino acid side chain vibrations, was used to map collagen deposition across heart tissue sections of a rat model of myocardial infarction, and was compared to conventional staining techniques. Comparison of the size of the collagen scar in heart tissue sections as measured with this methodology and that of trichrome staining showed a strong correlation (R=0.93). A Pearson correlation model between local intensity values in FT-IRIS and immuno-histochemical staining of collagen type I also showed a strong correlation (R=0.86). We demonstrate that FT-IRIS methodology can be utilized to visualize cardiac collagen deposition. In addition, given that vibrational spectroscopic data on proteins reflect molecular features, it also has the potential to provide additional information about the molecular structure of cardiac extracellular matrix proteins and their alterations.

  10. The influence of patient size on dose conversion coefficients: a hybrid phantom study for adult cardiac catheterization

    NASA Astrophysics Data System (ADS)

    Johnson, Perry; Lee, Choonsik; Johnson, Kevin; Siragusa, Daniel; Bolch, Wesley E.

    2009-06-01

    In this study, the influence of patient size on organ and effective dose conversion coefficients (DCCs) was investigated for a representative interventional fluoroscopic procedure—cardiac catheterization. The study was performed using hybrid phantoms representing an underweight, average and overweight American adult male. Reference body sizes were determined using the NHANES III database and parameterized based on standing height and total body mass. Organ and effective dose conversion coefficients were calculated for anterior-posterior, posterior-anterior, left anterior oblique and right anterior oblique projections using the Monte Carlo code MCNPX 2.5.0 with the metric dose area product being used as the normalization factor. Results show body size to have a clear influence on DCCs which increased noticeably when body size decreased. It was also shown that if patient size is neglected when choosing a DCC, the organ and effective dose will be underestimated to an underweight patient and will be overestimated to an underweight patient, with errors as large as 113% for certain projections. Results were further compared with those published for a KTMAN-2 Korean patient-specific tomographic phantom. The published DCCs aligned best with the hybrid phantom which most closely matched in overall body size. These results highlighted the need for and the advantages of phantom-patient matching, and it is recommended that hybrid phantoms be used to create a more diverse library of patient-dependent anthropomorphic phantoms for medical dose reconstruction.

  11. Serum Lipidomics Meets Cardiac Magnetic Resonance Imaging: Profiling of Subjects at Risk of Dilated Cardiomyopathy

    PubMed Central

    Sysi-Aho, Marko; Koikkalainen, Juha; Seppänen-Laakso, Tuulikki; Kaartinen, Maija; Kuusisto, Johanna; Peuhkurinen, Keijo; Kärkkäinen, Satu; Antila, Margareta; Lauerma, Kirsi; Reissell, Eeva; Jurkko, Raija; Lötjönen, Jyrki; Heliö, Tiina; Orešič, Matej

    2011-01-01

    Dilated cardiomyopathy (DCM), characterized by left ventricular dilatation and systolic dysfunction, constitutes a significant cause for heart failure, sudden cardiac death or need for heart transplantation. Lamin A/C gene (LMNA) on chromosome 1p12 is the most significant disease gene causing DCM and has been reported to cause 7–9% of DCM leading to cardiac transplantation. We have previously performed cardiac magnetic resonance imaging (MRI) to LMNA carriers to describe the early phenotype. Clinically, early recognition of subjects at risk of developing DCM would be important but is often difficult. Thus we have earlier used the MRI findings of these LMNA carriers for creating a model by which LMNA carriers could be identified from the controls at an asymptomatic stage. Some LMNA mutations may cause lipodystrophy. To characterize possible effects of LMNA mutations on lipid profile, we set out to apply global serum lipidomics using Ultra Performance Liquid Chromatography coupled to mass spectrometry in the same LMNA carriers, DCM patients without LMNA mutation and controls. All DCM patients, with or without LMNA mutation, differed from controls in regard to distinct serum lipidomic profile dominated by diminished odd-chain triglycerides and lipid ratios related to desaturation. Furthermore, we introduce a novel approach to identify associations between the molecular lipids from serum and the MR images from the LMNA carriers. The association analysis using dependency network and regression approaches also helped us to obtain novel insights into how the affected lipids might relate to cardiac shape and volume changes. Our study provides a framework for linking serum derived molecular markers not only with clinical endpoints, but also with the more subtle intermediate phenotypes, as derived from medical imaging, of potential pathophysiological relevance. PMID:21283746

  12. Serum lipidomics meets cardiac magnetic resonance imaging: profiling of subjects at risk of dilated cardiomyopathy.

    PubMed

    Sysi-Aho, Marko; Koikkalainen, Juha; Seppänen-Laakso, Tuulikki; Kaartinen, Maija; Kuusisto, Johanna; Peuhkurinen, Keijo; Kärkkäinen, Satu; Antila, Margareta; Lauerma, Kirsi; Reissell, Eeva; Jurkko, Raija; Lötjönen, Jyrki; Heliö, Tiina; Orešič, Matej

    2011-01-20

    Dilated cardiomyopathy (DCM), characterized by left ventricular dilatation and systolic dysfunction, constitutes a significant cause for heart failure, sudden cardiac death or need for heart transplantation. Lamin A/C gene (LMNA) on chromosome 1p12 is the most significant disease gene causing DCM and has been reported to cause 7-9% of DCM leading to cardiac transplantation. We have previously performed cardiac magnetic resonance imaging (MRI) to LMNA carriers to describe the early phenotype. Clinically, early recognition of subjects at risk of developing DCM would be important but is often difficult. Thus we have earlier used the MRI findings of these LMNA carriers for creating a model by which LMNA carriers could be identified from the controls at an asymptomatic stage. Some LMNA mutations may cause lipodystrophy. To characterize possible effects of LMNA mutations on lipid profile, we set out to apply global serum lipidomics using Ultra Performance Liquid Chromatography coupled to mass spectrometry in the same LMNA carriers, DCM patients without LMNA mutation and controls. All DCM patients, with or without LMNA mutation, differed from controls in regard to distinct serum lipidomic profile dominated by diminished odd-chain triglycerides and lipid ratios related to desaturation. Furthermore, we introduce a novel approach to identify associations between the molecular lipids from serum and the MR images from the LMNA carriers. The association analysis using dependency network and regression approaches also helped us to obtain novel insights into how the affected lipids might relate to cardiac shape and volume changes. Our study provides a framework for linking serum derived molecular markers not only with clinical endpoints, but also with the more subtle intermediate phenotypes, as derived from medical imaging, of potential pathophysiological relevance.

  13. Serum lipidomics meets cardiac magnetic resonance imaging: profiling of subjects at risk of dilated cardiomyopathy.

    PubMed

    Sysi-Aho, Marko; Koikkalainen, Juha; Seppänen-Laakso, Tuulikki; Kaartinen, Maija; Kuusisto, Johanna; Peuhkurinen, Keijo; Kärkkäinen, Satu; Antila, Margareta; Lauerma, Kirsi; Reissell, Eeva; Jurkko, Raija; Lötjönen, Jyrki; Heliö, Tiina; Orešič, Matej

    2011-01-01

    Dilated cardiomyopathy (DCM), characterized by left ventricular dilatation and systolic dysfunction, constitutes a significant cause for heart failure, sudden cardiac death or need for heart transplantation. Lamin A/C gene (LMNA) on chromosome 1p12 is the most significant disease gene causing DCM and has been reported to cause 7-9% of DCM leading to cardiac transplantation. We have previously performed cardiac magnetic resonance imaging (MRI) to LMNA carriers to describe the early phenotype. Clinically, early recognition of subjects at risk of developing DCM would be important but is often difficult. Thus we have earlier used the MRI findings of these LMNA carriers for creating a model by which LMNA carriers could be identified from the controls at an asymptomatic stage. Some LMNA mutations may cause lipodystrophy. To characterize possible effects of LMNA mutations on lipid profile, we set out to apply global serum lipidomics using Ultra Performance Liquid Chromatography coupled to mass spectrometry in the same LMNA carriers, DCM patients without LMNA mutation and controls. All DCM patients, with or without LMNA mutation, differed from controls in regard to distinct serum lipidomic profile dominated by diminished odd-chain triglycerides and lipid ratios related to desaturation. Furthermore, we introduce a novel approach to identify associations between the molecular lipids from serum and the MR images from the LMNA carriers. The association analysis using dependency network and regression approaches also helped us to obtain novel insights into how the affected lipids might relate to cardiac shape and volume changes. Our study provides a framework for linking serum derived molecular markers not only with clinical endpoints, but also with the more subtle intermediate phenotypes, as derived from medical imaging, of potential pathophysiological relevance. PMID:21283746

  14. Segmented k-space fast cardiac imaging using an echo-train readout.

    PubMed

    Epstein, F H; Wolff, S D; Arai, A E

    1999-03-01

    A segmented k-space fast gradient-echo pulse sequence with an echo-train readout (FGRE-ET) was developed for high-quality cine imaging of the heart in reduced scan times. Using segmented FGRE-ET, cine images of the heart can be acquired in as few as 1-5 heart beats and do not display the geometric distortion and flow-related artifacts typically associated with cardiac echoplanar imaging (EPI). Segmented FGRE-ET was compared with conventional segmented FGRE and with conventional multi-phase EPI in normal volunteers. Segmented FGRE-ET was found to have reduced temporal blurring compared with segmented FGRE for cine imaging in 4 heart beats (P<0.05). Also, segmented FGRE-ET did not display geometric distortion characteristic of conventional EPI (P<0.05). Segmented FGRE-ET may be particularly applicable to functional cardiac stress testing because it allows versatile cine imaging in very short breath-holds.

  15. Image-Based Structural Modeling of the Cardiac Purkinje Network

    PubMed Central

    Liu, Benjamin R.; Cherry, Elizabeth M.

    2015-01-01

    The Purkinje network is a specialized conduction system within the heart that ensures the proper activation of the ventricles to produce effective contraction. Its role during ventricular arrhythmias is less clear, but some experimental studies have suggested that the Purkinje network may significantly affect the genesis and maintenance of ventricular arrhythmias. Despite its importance, few structural models of the Purkinje network have been developed, primarily because current physical limitations prevent examination of the intact Purkinje network. In previous modeling efforts Purkinje-like structures have been developed through either automated or hand-drawn procedures, but these networks have been created according to general principles rather than based on real networks. To allow for greater realism in Purkinje structural models, we present a method for creating three-dimensional Purkinje networks based directly on imaging data. Our approach uses Purkinje network structures extracted from photographs of dissected ventricles and projects these flat networks onto realistic endocardial surfaces. Using this method, we create models for the combined ventricle-Purkinje system that can fully activate the ventricles through a stimulus delivered to the Purkinje network and can produce simulated activation sequences that match experimental observations. The combined models have the potential to help elucidate Purkinje network contributions during ventricular arrhythmias. PMID:26583120

  16. Sustained co-delivery of BIO and IGF-1 by a novel hybrid hydrogel system to stimulate endogenous cardiac repair in myocardial infarcted rat hearts

    PubMed Central

    Fang, Rui; Qiao, Shupei; Liu, Yi; Meng, Qingyuan; Chen, Xiongbiao; Song, Bing; Hou, Xiaolu; Tian, Weiming

    2015-01-01

    Dedifferentiation and proliferation of endogenous cardiomyocytes in situ can effectively improve cardiac repair following myocardial infarction (MI). 6-Bromoindirubin-3-oxime (BIO) and insulin-like growth factor 1 (IGF-1) are two potent factors that promote cardiomyocyte survival and proliferation. However, their delivery for sustained release in MI-affected areas has proved to be challenging. In the current research, we present a study on the sustained co-delivery of BIO and IGF-1 in a hybrid hydrogel system to simulate endogenous cardiac repair in an MI rat model. Both BIO and IGF-1 were efficiently encapsulated in gelatin nanoparticles, which were later cross-linked with the oxidized alginate to form a novel hybrid hydrogel system. The in vivo results indicated that the hybrid system could enhance the proliferation of cardiomyocytes in situ and could promote revascularization around the MI sites, allowing improved cardiac function. Taken together, we concluded that the hybrid hydrogel system can co-deliver BIO and IGF-1 to areas of MI and thus improve cardiac function by promoting the proliferation of cardiomyocytes and revascularization. PMID:26251592

  17. Cardiac motion correction based on partial angle reconstructed images in x-ray CT

    SciTech Connect

    Kim, Seungeon; Chang, Yongjin; Ra, Jong Beom

    2015-05-15

    Purpose: Cardiac x-ray CT imaging is still challenging due to heart motion, which cannot be ignored even with the current rotation speed of the equipment. In response, many algorithms have been developed to compensate remaining motion artifacts by estimating the motion using projection data or reconstructed images. In these algorithms, accurate motion estimation is critical to the compensated image quality. In addition, since the scan range is directly related to the radiation dose, it is preferable to minimize the scan range in motion estimation. In this paper, the authors propose a novel motion estimation and compensation algorithm using a sinogram with a rotation angle of less than 360°. The algorithm estimates the motion of the whole heart area using two opposite 3D partial angle reconstructed (PAR) images and compensates the motion in the reconstruction process. Methods: A CT system scans the thoracic area including the heart over an angular range of 180° + α + β, where α and β denote the detector fan angle and an additional partial angle, respectively. The obtained cone-beam projection data are converted into cone-parallel geometry via row-wise fan-to-parallel rebinning. Two conjugate 3D PAR images, whose center projection angles are separated by 180°, are then reconstructed with an angular range of β, which is considerably smaller than a short scan range of 180° + α. Although these images include limited view angle artifacts that disturb accurate motion estimation, they have considerably better temporal resolution than a short scan image. Hence, after preprocessing these artifacts, the authors estimate a motion model during a half rotation for a whole field of view via nonrigid registration between the images. Finally, motion-compensated image reconstruction is performed at a target phase by incorporating the estimated motion model. The target phase is selected as that corresponding to a view angle that is orthogonal to the center view angles of

  18. Cardiac and vascular imaging with labeled platelets and leukocytes

    SciTech Connect

    Dewanjee, M.K.

    1984-07-01

    The contribution of platelets in atherosclerosis and thrombosis in animal models and in clinical studies has been quantified with 111In-platelet scintigraphy. New in vitro quantitative techniques have been developed using 111In-labeled platelets to determine the number of adherent platelets on deendothelialized surfaces of damaged vessel walls and synthetic vascular grafts. In vivo imaging techniques are semi-quantitative in nature; in these studies 111In radioactivity on thrombotic vessels or graft surfaces of iliac, femoral, or popliteal arteries is compared with contralateral vessels. Background 111In radioactivity in the circulating blood pool of venous and capillary networks and radioactivity in marrow decreases the sensitivity of these techniques. Subtraction of blood pool radioactivity with 99mTc-labeled autologous red cells and calculation of 111In radioactivity associated with platelet thrombus on vessel walls also have been performed for coronary, carotid, and femoral arteries. Although platelet concentrates are used frequently after open heart surgery (one to six per patient), consumption of platelets in the artificial lung or oxygenator, lysis of platelets during pumping, and suction of blood only recently have been quantified with the use of 111In-labeled platelets. These studies also demonstrated far less trauma to platelets with the use of a membrane rather than a bubble oxygenator. Further reduction in platelet consumption and trauma was observed with the use of prostacyclin, a short-acting drug with significant beneficial effect on platelet thrombus reduction and disaggregation of aggregated platelets. The role of polymorphonuclear leukocytes in inflammation, infection and myocardial infarction, and in vivo evaluation with 111In-leukocyte scintigraphy in animals and humans has been described.

  19. Hybrid-modality high-resolution imaging: for diagnostic biomedical imaging and sensing for disease diagnosis

    NASA Astrophysics Data System (ADS)

    Murukeshan, Vadakke M.; Hoong Ta, Lim

    2014-11-01

    Medical diagnostics in the recent past has seen the challenging trend to come up with dual and multi-modality imaging for implementing better diagnostic procedures. The changes in tissues in the early disease stages are often subtle and can occur beneath the tissue surface. In most of these cases, conventional types of medical imaging using optics may not be able to detect these changes easily due to its penetration depth of the orders of 1 mm. Each imaging modality has its own advantages and limitations, and the use of a single modality is not suitable for every diagnostic applications. Therefore the need for multi or hybrid-modality imaging arises. Combining more than one imaging modalities overcomes the limitation of individual imaging method and integrates the respective advantages into a single setting. In this context, this paper will be focusing on the research and development of two multi-modality imaging platforms. The first platform combines ultrasound and photoacoustic imaging for diagnostic applications in the eye. The second platform consists of optical hyperspectral and photoacoustic imaging for diagnostic applications in the colon. Photoacoustic imaging is used as one of the modalities in both platforms as it can offer deeper penetration depth compared to optical imaging. The optical engineering and research challenges in developing the dual/multi-modality platforms will be discussed, followed by initial results validating the proposed scheme. The proposed schemes offer high spatial and spectral resolution imaging and sensing, and is expected to offer potential biomedical imaging solutions in the near future.

  20. Reference Values for Cardiac and Aortic Magnetic Resonance Imaging in Healthy, Young Caucasian Adults

    PubMed Central

    Eikendal, Anouk L. M.; Bots, Michiel L.; Haaring, Cees; Saam, Tobias; van der Geest, Rob J.; Westenberg, Jos J. M.; den Ruijter, Hester M.; Hoefer, Imo E.; Leiner, Tim

    2016-01-01

    Background Reference values for morphological and functional parameters of the cardiovascular system in early life are relevant since they may help to identify young adults who fall outside the physiological range of arterial and cardiac ageing. This study provides age and sex specific reference values for aortic wall characteristics, cardiac function parameters and aortic pulse wave velocity (PWV) in a population-based sample of healthy, young adults using magnetic resonance (MR) imaging. Materials and Methods In 131 randomly selected healthy, young adults aged between 25 and 35 years (mean age 31.8 years, 63 men) of the general-population based Atherosclerosis-Monitoring-and-Biomarker-measurements-In-The-YOuNg (AMBITYON) study, descending thoracic aortic dimensions and wall thickness, thoracic aortic PWV and cardiac function parameters were measured using a 3.0T MR-system. Age and sex specific reference values were generated using dedicated software. Differences in reference values between two age groups (25–30 and 30–35 years) and both sexes were tested. Results Aortic diameters and areas were higher in the older age group (all p<0.007). Moreover, aortic dimensions, left ventricular mass, left and right ventricular volumes and cardiac output were lower in women than in men (all p<0.001). For mean and maximum aortic wall thickness, left and right ejection fraction and aortic PWV we did not observe a significant age or sex effect. Conclusion This study provides age and sex specific reference values for cardiovascular MR parameters in healthy, young Caucasian adults. These may aid in MR guided pre-clinical identification of young adults who fall outside the physiological range of arterial and cardiac ageing. PMID:27732640

  1. Rotating and semi-stationary multi-beamline architecture study for cardiac CT imaging

    NASA Astrophysics Data System (ADS)

    Wang, Jiao; Fitzgerald, Paul; Gao, Hewei; Jin, Yannan; Wang, Ge; De Man, Bruno

    2014-03-01

    Over the past decade, there has been abundant research on future cardiac CT architectures and corresponding reconstruction algorithms. Multiple cardiac CT concepts have been published, including third-generation single-source CT with wide-cone coverage, dual-source CT, and electron-beam CT, etc. In this paper, we apply a Radon space analysis method to two multi-beamline architectures: triple-source CT and semi-stationary ring-source CT. In our studies, we have considered more than thirty cardiac CT architectures and triple-source CT was identified as a promising solution, offering approximately a three-fold advantage in temporal resolution, which can significantly reduce motion artifacts due to the moving heart and lungs. In this work, we describe a triple-source CT architecture with all three beamlines (i.e. source-detector pairs) limited to the cardiac field of view in order to eliminate the radiation dose outside the cardiac region. We also demonstrate the capability of performing full field of view imaging when desired, by shifting the detectors. Ring-source dual-rotating-detector CT is another architecture of interest, which offers the opportunity to provide high temporal resolution using a full-ring stationary source. With this semi-stationary architecture, we found that the azimuthal blur effect can be greater than in a fully-rotating CT system. We therefore propose novel scanning modes to reduce the azimuthal blur in ring-source rotating detector CT. Radon space analysis method proves to be a useful method in CT system architecture study.

  2. Contrast agents and cardiac MR imaging of myocardial ischemia: from bench to bedside.

    PubMed

    Croisille, Pierre; Revel, Didier; Saeed, Maythem

    2006-09-01

    This review paper presents, in the first part, the different classes of contrast media that are already used or are in development for cardiac magnetic resonance imaging. A classification of the different types of contrast media is proposed based on the distribution of the compounds in the body, their type of relaxivity and their potential affinity to particular molecules. In the second part, the different uses of the extracellular type of T1-enhancing contrast agent for myocardial imaging is covered from the detection of stable coronary artery disease to the detection and characterization of chronic infarction. A particular emphasis is placed on the clinical use of gadolinium-chelates, which are the universally used type of MRI contrast agent in the clinical routine. Both approaches, first-pass magnetic resonance imaging (FP-MRI) as well as delayed-enhanced magnetic resonance imaging (DE-MRI), are covered in the different situations of acute and chronic myocardial infarction. PMID:16633792

  3. Live dynamic imaging and analysis of developmental cardiac defects in mouse models with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Lopez, Andrew L.; Wang, Shang; Garcia, Monica; Valladolid, Christian; Larin, Kirill V.; Larina, Irina V.

    2015-03-01

    Understanding mouse embryonic development is an invaluable resource for our interpretation of normal human embryology and congenital defects. Our research focuses on developing methods for live imaging and dynamic characterization of early embryonic development in mouse models of human diseases. Using multidisciplinary methods: optical coherence tomography (OCT), live mouse embryo manipulations and static embryo culture, molecular biology, advanced image processing and computational modeling we aim to understand developmental processes. We have developed an OCT based approach to image live early mouse embryos (E8.5 - E9.5) cultured on an imaging stage and visualize developmental events with a spatial resolution of a few micrometers (less than the size of an individual cell) and a frame rate of up to hundreds of frames per second and reconstruct cardiodynamics in 4D (3D+time). We are now using these methods to study how specific embryonic lethal mutations affect cardiac morphology and function during early development.

  4. Recent Advances in Cardiac Computed Tomography: Dual Energy, Spectral and Molecular CT Imaging

    PubMed Central

    Danad, Ibrahim; Fayad, Zahi A.; Willemink, Martin J.; Min, James K.

    2015-01-01

    Computed tomography (CT) evolved into a powerful diagnostic tool and it is impossible to imagine current clinical practice without CT imaging. Due to its widespread availability, ease of clinical application, superb sensitivity for detection of CAD, and non-invasive nature, CT has become a valuable tool within the armamentarium of the cardiologist. In the last few years, numerous technological advances in CT have occurred—including dual energy CT (DECT), spectral CT and CT-based molecular imaging. By harnessing the advances in technology, cardiac CT has advanced beyond the mere evaluation of coronary stenosis to an imaging modality tool that permits accurate plaque characterization, assessment of myocardial perfusion and even probing of molecular processes that are involved in coronary atherosclerosis. Novel innovations in CT contrast agents and pre-clinical spectral CT devices have paved the way for CT-based molecular imaging. PMID:26068288

  5. Bimodal biophotonic imaging of the structure-function relationship in cardiac tissue

    PubMed Central

    Hucker, William J.; Ripplinger, Crystal M.; Fleming, Christine P.; Fedorov, Vadim V.; Rollins, Andrew M.; Efimov, Igor R.

    2009-01-01

    The development of systems physiology is hampered by the limited ability to relate tissue structure and function in intact organs in vivo or in vitro. Here, we show the application of a bimodal biophotonic imaging approach that employs optical coherence tomography and fluorescent imaging to investigate the structure-function relationship at the tissue level in the heart. Reconstruction of cardiac excitation and structure was limited by the depth penetration of bimodal imaging to ∼2 mm in atrial tissue, and ∼1 mm in ventricular myocardium. The subcellular resolution of optical coherence tomography clearly demonstrated that microscopic fiber orientation governs the pattern of wave propagation in functionally characterized rabbit sinoatrial and atrioventricular nodal preparations and revealed structural heterogeneities contributing to ventricular arrhythmias. The combination of this bimodal biophotonic imaging approach with histology and/or immunohistochemistry can span multiple scales of resolution for the investigation of the molecular and structural determinants of intact tissue physiology. PMID:19021392

  6. RNA Imaging with Multiplexed Error Robust Fluorescence in situ Hybridization

    PubMed Central

    Moffitt, Jeffrey R.; Zhuang, Xiaowei

    2016-01-01

    Quantitative measurements of both the copy number and spatial distribution of large fractions of the transcriptome in single-cells could revolutionize our understanding of a variety of cellular and tissue behaviors in both healthy and diseased states. Single-molecule Fluorescence In Situ Hybridization (smFISH)—an approach where individual RNAs are labeled with fluorescent probes and imaged in their native cellular and tissue context—provides both the copy number and spatial context of RNAs but has been limited in the number of RNA species that can be measured simultaneously. Here we describe Multiplexed Error Robust Fluorescence In Situ Hybridization (MERFISH), a massively parallelized form of smFISH that can image and identify hundreds to thousands of different RNA species simultaneously with high accuracy in individual cells in their native spatial context. We provide detailed protocols on all aspects of MERFISH, including probe design, data collection, and data analysis to allow interested laboratories to perform MERFISH measurements themselves. PMID:27241748

  7. An infant with diaphragmatic hernia, anophthalmia and cardiac defect: evaluation by magnetic resonance imaging autopsy.

    PubMed

    Ceylaner, S; Gozer, H E; Ceylaner, G; Ertas, I E; Kizilates, S U; Edguer, T

    2006-01-01

    We present an infant with diaphragmatic hernia, anophthalmia and cardiac defect evaluated by magnetic resonance imaging (MRI) autopsy. This female infant was born at 39th weeks by vaginal delivery and presented with diaphragmatic hernia, anophthalmia, cardiac defect and died due to respiratory problems at 28th hours of life. MRI autopsy showed internal organ abnormalities including congenital hernia of the left diaphragm, secondary hypoplasia of the left lung, atrial and ventricular septal defect, dilatation of calices of the kidneys, bilateral anophthalmia, hypoplasia of the optic nerves, hyperintensity of pituitary gland possibly due to bleeding and a cyst of the septum pellucidum. This article shows that MRI autopsy is a valuable method for the evaluation of cases with congenital anomalies if autopsy is not possible.

  8. Three-dimensional Content-Based Cardiac Image Retrieval using global and local descriptors

    PubMed Central

    Bergamasco, Leila C. C.; Nunes, Fátima L. S.

    2015-01-01

    The increase in volume of medical images generated and stored has created difficulties in accurate image retrieval. An alternative is to generate three-dimensional (3D) models from such medical images and use them in the search. Some of the main cardiac illnesses, such as Congestive Heart Failure (CHF), have deformation in the heart’s shape as one of the main symptoms, which can be identified faster in a 3D object than in slices. This article presents techniques developed to retrieve 3D cardiac models using global and local descriptors within a content-based image retrieval system. These techniques were applied in pre-classified 3D models with and without the CHF disease and they were evaluated by using Precision vs. Recall metric. We observed that local descriptors achieved better results than a global descriptor, reaching 85% of accuracy. The results confirmed the potential of using 3D models retrieval in the medical context to aid in the diagnosis. PMID:26958280

  9. Three-dimensional Content-Based Cardiac Image Retrieval using global and local descriptors.

    PubMed

    Bergamasco, Leila C C; Nunes, Fátima L S

    2015-01-01

    The increase in volume of medical images generated and stored has created difficulties in accurate image retrieval. An alternative is to generate three-dimensional (3D) models from such medical images and use them in the search. Some of the main cardiac illnesses, such as Congestive Heart Failure (CHF), have deformation in the heart's shape as one of the main symptoms, which can be identified faster in a 3D object than in slices. This article presents techniques developed to retrieve 3D cardiac models using global and local descriptors within a content-based image retrieval system. These techniques were applied in pre-classified 3D models with and without the CHF disease and they were evaluated by using Precision vs. Recall metric. We observed that local descriptors achieved better results than a global descriptor, reaching 85% of accuracy. The results confirmed the potential of using 3D models retrieval in the medical context to aid in the diagnosis. PMID:26958280

  10. Improving Low-dose Cardiac CT Images based on 3D Sparse Representation

    NASA Astrophysics Data System (ADS)

    Shi, Luyao; Hu, Yining; Chen, Yang; Yin, Xindao; Shu, Huazhong; Luo, Limin; Coatrieux, Jean-Louis

    2016-03-01

    Cardiac computed tomography (CCT) is a reliable and accurate tool for diagnosis of coronary artery diseases and is also frequently used in surgery guidance. Low-dose scans should be considered in order to alleviate the harm to patients caused by X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. In order to improve the cardiac LDCT image quality, a 3D sparse representation-based processing (3D SR) is proposed by exploiting the sparsity and regularity of 3D anatomical features in CCT. The proposed method was evaluated by a clinical study of 14 patients. The performance of the proposed method was compared to the 2D spares representation-based processing (2D SR) and the state-of-the-art noise reduction algorithm BM4D. The visual assessment, quantitative assessment and qualitative assessment results show that the proposed approach can lead to effective noise/artifact suppression and detail preservation. Compared to the other two tested methods, 3D SR method can obtain results with image quality most close to the reference standard dose CT (SDCT) images.

  11. A framework of whole heart extracellular volume fraction estimation for low dose cardiac CT images

    NASA Astrophysics Data System (ADS)

    Chen, Xinjian; Summers, Ronald M.; Nacif, Marcelo Souto; Liu, Songtao; Bluemke, David A.; Yao, Jianhua

    2012-02-01

    Cardiac magnetic resonance imaging (CMRI) has been well validated and allows quantification of myocardial fibrosis in comparison to overall mass of the myocardium. Unfortunately, CMRI is relatively expensive and is contraindicated in patients with intracardiac devices. Cardiac CT (CCT) is widely available and has been validated for detection of scar and myocardial stress/rest perfusion. In this paper, we sought to evaluate the potential of low dose CCT for the measurement of myocardial whole heart extracellular volume (ECV) fraction. A novel framework was proposed for CCT whole heart ECV estimation, which consists of three main steps. First, a shape constrained graph cut (GC) method was proposed for myocardium and blood pool segmentation for post-contrast image. Second, the symmetric Demons deformable registrations method was applied to register pre-contrast to post-contrast images. Finally, the whole heart ECV value was computed. The proposed method was tested on 7 clinical low dose CCT datasets with pre-contrast and post-contrast images. The preliminary results demonstrated the feasibility and efficiency of the proposed method.

  12. Two-Photon Imaging within the Murine Thorax without Respiratory and Cardiac Motion Artifact

    PubMed Central

    Presson, Robert G.; Brown, Mary Beth; Fisher, Amanda J.; Sandoval, Ruben M.; Dunn, Kenneth W.; Lorenz, Kevin S.; Delp, Edward J.; Salama, Paul; Molitoris, Bruce A.; Petrache, Irina

    2011-01-01

    Intravital microscopy has been recognized for its ability to make physiological measurements at cellular and subcellular levels while maintaining the complex natural microenvironment. Two-photon microscopy (TPM), using longer wavelengths than single-photon excitation, has extended intravital imaging deeper into tissues, with minimal phototoxicity. However, due to a relatively slow acquisition rate, TPM is especially sensitive to motion artifact, which presents a challenge when imaging tissues subject to respiratory and cardiac movement. Thoracoabdominal organs that cannot be exteriorized or immobilized during TPM have generally required the use of isolated, pump-perfused preparations. However, this approach entails significant alteration of normal physiology, such as a lack of neural inputs, increased vascular resistance, and leukocyte activation. We adapted techniques of intravital microscopy that permitted TPM of organs maintained within the thoracoabdominal cavity of living, breathing rats or mice. We obtained extended intravital TPM imaging of the intact lung, arguably the organ most susceptible to both respiratory and cardiac motion. Intravital TPM detected the development of lung microvascular endothelial activation manifested as increased leukocyte adhesion and plasma extravasation in response to oxidative stress inducers PMA or soluble cigarette smoke extract. The pulmonary microvasculature and alveoli in the intact animal were imaged with comparable detail and fidelity to those in pump-perfused animals, opening the possibility for TPM of other thoracoabdominal organs under physiological and pathophysiological conditions. PMID:21703395

  13. Nicotinamide adenine dinucleotide fluorescence spectroscopy and imaging of isolated cardiac myocytes.

    PubMed Central

    Eng, J; Lynch, R M; Balaban, R S

    1989-01-01

    Nicotinamide adenine dinucleotide (NADH) plays a critical role in oxidative phosphorylation as the primary source of reducing equivalents to the respiratory chain. Using a modified fluorescence microscope, we have obtained spectra and images of the blue autofluorescence from single rat cardiac myocytes. The optical setup permitted rapid acquisition of fluorescence emission spectra (390-595 nm) or intensified digital video images of individual myocytes. The spectra showed a broad fluorescence centered at 447 +/- 0.2 nm, consistent with mitochondrial NADH. Addition of cyanide resulted in a 100 +/- 10% increase in fluorescence, while the uncoupler FCCP resulted in a 82 +/- 4% decrease. These two transitions were consistent with mitochondrial NADH and implied that the myocytes were 44 +/- 6% reduced under the resting control conditions. Intracellular fluorescent structures were observed that correlated with the distribution of a mitochondrial selective fluorescent probe (DASPMI), the mitochondrial distribution seen in published electron micrographs, and a metabolic digital subtraction image of the cyanide fluorescence transition. These data are consistent with the notion that the blue autofluorescence of rat cardiac myocytes originates from mitochondrial NADH. Images FIGURE 9 FIGURE 10 FIGURE 2 FIGURE 3 FIGURE 8 FIGURE 11 PMID:2720061

  14. Improving Low-dose Cardiac CT Images based on 3D Sparse Representation

    PubMed Central

    Shi, Luyao; Hu, Yining; Chen, Yang; Yin, Xindao; Shu, Huazhong; Luo, Limin; Coatrieux, Jean-Louis

    2016-01-01

    Cardiac computed tomography (CCT) is a reliable and accurate tool for diagnosis of coronary artery diseases and is also frequently used in surgery guidance. Low-dose scans should be considered in order to alleviate the harm to patients caused by X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. In order to improve the cardiac LDCT image quality, a 3D sparse representation-based processing (3D SR) is proposed by exploiting the sparsity and regularity of 3D anatomical features in CCT. The proposed method was evaluated by a clinical study of 14 patients. The performance of the proposed method was compared to the 2D spares representation-based processing (2D SR) and the state-of-the-art noise reduction algorithm BM4D. The visual assessment, quantitative assessment and qualitative assessment results show that the proposed approach can lead to effective noise/artifact suppression and detail preservation. Compared to the other two tested methods, 3D SR method can obtain results with image quality most close to the reference standard dose CT (SDCT) images. PMID:26980176

  15. Image-based estimation of ventricular fiber orientations for personalized modeling of cardiac electrophysiology.

    PubMed

    Vadakkumpadan, Fijoy; Arevalo, Hermenegild; Ceritoglu, Can; Miller, Michael; Trayanova, Natalia

    2012-05-01

    Technological limitations pose a major challenge to acquisition of myocardial fiber orientations for patient-specific modeling of cardiac (dys)function and assessment of therapy. The objective of this project was to develop a methodology to estimate cardiac fiber orientations from in vivo images of patient heart geometries. An accurate representation of ventricular geometry and fiber orientations was reconstructed, respectively, from high-resolution ex vivo structural magnetic resonance (MR) and diffusion tensor (DT) MR images of a normal human heart, referred to as the atlas. Ventricular geometry of a patient heart was extracted, via semiautomatic segmentation, from an in vivo computed tomography (CT) image. Using image transformation algorithms, the atlas ventricular geometry was deformed to match that of the patient. Finally, the deformation field was applied to the atlas fiber orientations to obtain an estimate of patient fiber orientations. The accuracy of the fiber estimates was assessed using six normal and three failing canine hearts. The mean absolute difference between inclination angles of acquired and estimated fiber orientations was 15.4°. Computational simulations of ventricular activation maps and pseudo-ECGs in sinus rhythm and ventricular tachycardia indicated that there are no significant differences between estimated and acquired fiber orientations at a clinically observable level. PMID:22271833

  16. Improving Low-dose Cardiac CT Images based on 3D Sparse Representation.

    PubMed

    Shi, Luyao; Hu, Yining; Chen, Yang; Yin, Xindao; Shu, Huazhong; Luo, Limin; Coatrieux, Jean-Louis

    2016-03-16

    Cardiac computed tomography (CCT) is a reliable and accurate tool for diagnosis of coronary artery diseases and is also frequently used in surgery guidance. Low-dose scans should be considered in order to alleviate the harm to patients caused by X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. In order to improve the cardiac LDCT image quality, a 3D sparse representation-based processing (3D SR) is proposed by exploiting the sparsity and regularity of 3D anatomical features in CCT. The proposed method was evaluated by a clinical study of 14 patients. The performance of the proposed method was compared to the 2D spares representation-based processing (2D SR) and the state-of-the-art noise reduction algorithm BM4D. The visual assessment, quantitative assessment and qualitative assessment results show that the proposed approach can lead to effective noise/artifact suppression and detail preservation. Compared to the other two tested methods, 3D SR method can obtain results with image quality most close to the reference standard dose CT (SDCT) images.

  17. Imaging cardiac activation sequence during ventricular tachycardia in a canine model of nonischemic heart failure.

    PubMed

    Han, Chengzong; Pogwizd, Steven M; Yu, Long; Zhou, Zhaoye; Killingsworth, Cheryl R; He, Bin

    2015-01-15

    Noninvasive cardiac activation imaging of ventricular tachycardia (VT) is important in the clinical diagnosis and treatment of arrhythmias in heart failure (HF) patients. This study investigated the ability of the three-dimensional cardiac electrical imaging (3DCEI) technique for characterizing the activation patterns of spontaneously occurring and norepinephrine (NE)-induced VTs in a newly developed arrhythmogenic canine model of nonischemic HF. HF was induced by aortic insufficiency followed by aortic constriction in three canines. Up to 128 body-surface ECGs were measured simultaneously with bipolar recordings from up to 232 intramural sites in a closed-chest condition. Data analysis was performed on the spontaneously occurring VTs (n=4) and the NE-induced nonsustained VTs (n=8) in HF canines. Both spontaneously occurring and NE-induced nonsustained VTs initiated by a focal mechanism primarily from the subendocardium, but occasionally from the subepicardium of left ventricle. Most focal initiation sites were located at apex, right ventricular outflow tract, and left lateral wall. The NE-induced VTs were longer, more rapid, and had more focal sites than the spontaneously occurring VTs. Good correlation was obtained between imaged activation sequence and direct measurements (averaged correlation coefficient of ∼0.70 over 135 VT beats). The reconstructed initiation sites were ∼10 mm from measured initiation sites, suggesting good localization in such a large animal model with cardiac size similar to a human. Both spontaneously occurring and NE-induced nonsustained VTs had focal initiation in this canine model of nonischemic HF. 3DCEI is feasible to image the activation sequence and help define arrhythmia mechanism of nonischemic HF-associated VTs. PMID:25416188

  18. Lossy cardiac x-ray image compression based on acquisition noise

    NASA Astrophysics Data System (ADS)

    de Bruijn, Frederik J.; Slump, Cornelis H.

    1997-05-01

    In lossy medical image compression, the requirements for the preservation of diagnostic integrity cannot be easily formulated in terms of a perceptual model. Especially since, in reality, human visual perception is dependent on numerous factors such as the viewing conditions and psycho-visual factors. Therefore, we investigate the possibility to develop alternative measures for data loss, based on the characteristics of the acquisition system, in our case, a digital cardiac imaging system. In general, due to the low exposure, cardiac x-ray images tend to be relatively noisy. The main noise contributions are quantum noise and electrical noise. The electrical noise is not correlated with the signal. In addition, the signal can be transformed such that the correlated Poisson-distributed quantum noise is transformed into an additional zero-mean Gaussian noise source which is uncorrelated with the signal. Furthermore, the systems modulation transfer function imposes a known spatial-frequency limitation to the output signal. In the assumption that noise which is not correlated with the signal contains no diagnostic information, we have derived a compression measure based on the acquisition parameters of a digital cardiac imaging system. The measure is used for bit- assignment and quantization of transform coefficients. We present a blockwise-DCT compression algorithm which is based on the conventional JPEG-standard. However, the bit- assignment to the transform coefficients is now determined by an assumed noise variance for each coefficient, for a given set of acquisition parameters. Experiments with the algorithm indicate that a bit rate of 0.6 bit/pixel is feasible, without apparent loss of clinical information.

  19. Measuring and mapping cardiac fiber and laminar architecture using diffusion tensor MR imaging.

    PubMed

    Helm, Patrick; Beg, Mirza Faisal; Miller, Michael I; Winslow, Raimond L

    2005-06-01

    The ventricular myocardium is known to exhibit a complex spatial organization, with fiber orientation varying as a function of transmural location. It is now well established that diffusion tensor magnetic resonance imaging (DTMRI) may be used to measure this fiber orientation at high spatial resolution. Cardiac fibers are also known to be organized in sheets with surface orientation varying throughout the ventricles. This article reviews results on use of DTMRI for measuring ventricular fiber orientation, as well as presents new results providing strong evidence that the tertiary eigenvector of the diffusion tensor is aligned locally with the cardiac sheet surface normal. Considered together, these data indicate that DTMRI may be used to reconstruct both ventricular fiber and sheet organization. This article also presents the large deformation diffeomorphic metric mapping (LDDMM) algorithm and shows that this algorithm may be used to bring ensembles of imaged and reconstructed hearts into correspondence (e.g., registration) so that variability of ventricular geometry, fiber, and sheet orientation may be quantified. Ventricular geometry and fiber structure is known to be remodeled in a range of disease processes; however, descriptions of this remodeling have remained subjective and qualitative. We anticipate that use of DTMRI for reconstruction of ventricular anatomy coupled with application of the LDDMM method for image volume registration will enable the detection and quantification of changes in cardiac anatomy that are characteristic of specific disease processes in the heart. Finally, we show that epicardial electrical mapping and DTMRI imaging may be performed in the same hearts. The anatomic data may then be used to simulate electrical conduction in a computational model of the very same heart that was mapped electrically. This facilitates direct comparison and testing of model versus experimental results and opens the door to quantitative measurement

  20. Diminishing the impact of the partial volume effect in cardiac SPECT perfusion imaging.

    PubMed

    Pretorius, P Hendrik; King, Michael A

    2009-01-01

    The partial volume effect (PVE) significantly restricts the absolute quantification of regional myocardial uptake and thereby limits the accuracy of absolute measurement of blood flow and coronary flow reserve by SPECT. The template-projection-reconstruction method has been previously developed for PVE compensation. This method assumes the availability of coregistered high-spatial resolution anatomical information as is now becoming available with commercial dual-modality imaging systems such as SPECT/CTs. The objective of this investigation was to determine the extent to which the impact of the PVE on cardiac perfusion SPECT imaging can be diminished if coregistered high-spatial resolution anatomical information is available. For this investigation the authors introduced an additional parameter into the template-projection-reconstruction compensation equation called the voxel filling fraction (F). This parameter specifies the extent to which structure edge voxels in the emission reconstruction are filled by the structure in question as determined by the higher spatial-resolution imaging modality and the fractional presence of the structure at different states of physiological motion as in combining phases of cardiac motion. During correction the removal of spillover to the cardiac region from the surrounding structures is performed first by using reconstructed templates of neighboring structures (liver, blood pool, lungs) to calculate spillover fractions. This is followed by determining recovery coefficients for all voxels within the heart wall from the reconstruction of the template projections of the left and right ventricles (LV and RV). The emission data are subsequently divided by these recovery coefficients taking into account the filling fraction F. The mathematical cardiac torso phantom was used for investigation correction of PVE for a normal LV distribution, a defect in the inferior wall, and a defect in the anterior wall. PVE correction resulted in a

  1. Highly precise digital image stabilization scheme for a hybrid stabilizing system

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Hyung; Byun, Keun-Yung; Ko, Sung-Jea

    2010-07-01

    We propose a highly precise digital image stabilization (DIS) scheme for a hybrid stabilizing system. The stabilizing system adopts a hybrid method of using both optical image stabilization (OIS) and DIS. In the stabilizing system, OIS prestabilizes the original unstable image using gyro-sensors, and the resultant image obtained from OIS is post-stabilized using DIS to remove the residual jitters less than one pixel. The proposed DIS, which is newly designed using control-grid interpolation, can remove not only translational jitters but also rotational ones simultaneously. Experimental results show that the proposed hybrid image stabilizer achieves considerable performance improvement against conventional stabilization techniques.

  2. Watermarked cardiac CT image segmentation using deformable models and the Hermite transform

    NASA Astrophysics Data System (ADS)

    Gomez-Coronel, Sandra L.; Moya-Albor, Ernesto; Escalante-Ramírez, Boris; Brieva, Jorge

    2015-01-01

    Medical image watermarking is an open area for research and is a solution for the protection of copyright and intellectual property. One of the main challenges of this problem is that the marked images should not differ perceptually from the original images allowing a correct diagnosis and authentication. Furthermore, we also aim at obtaining watermarked images with very little numerical distortion so that computer vision tasks such as segmentation of important anatomical structures do not be impaired or affected. We propose a preliminary watermarking application in cardiac CT images based on a perceptive approach that includes a brightness model to generate a perceptive mask and identify the image regions where the watermark detection becomes a difficult task for the human eye. We propose a normalization scheme of the image in order to improve robustness against geometric attacks. We follow a spread spectrum technique to insert an alphanumeric code, such as patient's information, within the watermark. The watermark scheme is based on the Hermite transform as a bio-inspired image representation model. In order to evaluate the numerical integrity of the image data after watermarking, we perform a segmentation task based on deformable models. The segmentation technique is based on a vector-value level sets method such that, given a curve in a specific image, and subject to some constraints, the curve can evolve in order to detect objects. In order to stimulate the curve evolution we introduce simultaneously some image features like the gray level and the steered Hermite coefficients as texture descriptors. Segmentation performance was assessed by means of the Dice index and the Hausdorff distance. We tested different mark sizes and different insertion schemes on images that were later segmented either automatic or manual by physicians.

  3. Role of Cardiac Magnetic Resonance Imaging in the Management and Treatment of Ventricular Tachycardia in Patients With Structural Heart Disease.

    PubMed

    Mehrotra, Amit K; Callans, David

    2015-01-01

    Treatment for ventricular tachycardia (VT) generally includes 1 or more of the following options: antiarrhythmic therapy, an implantable cardioverter-defibrillator and/or catheter ablation. Catheter ablation is performed with an electroanatomic mapping system to define the heart's 3D anatomy, as well as regions of scar. Radiofrequency energy is then applied to areas of abnormal substrate within which are located channels critical to the VT circuit. Cardiac magnetic resonance (CMR) imaging is a non-invasive modality that provides high-resolution images of cardiac structure and function. CMR has become a very useful tool for sudden cardiac death risk stratification and to facilitate successful radiofrequency ablation of VT in patients with abnormal cardiac substrate. The role of CMR in the management and treatment of VT in patients with structural heart disease is reviewed.

  4. Magnetic resonance imaging in patients with cardiac pacemakers: era of "MR Conditional" designs

    PubMed Central

    2011-01-01

    Advances in cardiac device technology have led to the first generation of magnetic resonance imaging (MRI) conditional devices, providing more diagnostic imaging options for patients with these devices, but also new controversies. Prior studies of pacemakers in patients undergoing MRI procedures have provided groundwork for design improvements. Factors related to magnetic field interactions and transfer of electromagnetic energy led to specific design changes. Ferromagnetic content was minimized. Reed switches were modified. Leads were redesigned to reduce induced currents/heating. Circuitry filters and shielding were implemented to impede or limit the transfer of certain unwanted electromagnetic effects. Prospective multicenter clinical trials to assess the safety and efficacy of the first generation of MR conditional cardiac pacemakers demonstrated no significant alterations in pacing parameters compared to controls. There were no reported complications through the one month visit including no arrhythmias, electrical reset, inhibition of generator output, or adverse sensations. The safe implementation of these new technologies requires an understanding of the well-defined patient and MR system conditions. Although scanning a patient with an MR conditional device following the strictly defined patient and MR system conditions appears straightforward, issues related to patients with pre-existing devices remain complex. Until MR conditional devices are the routine platform for all of these devices, there will still be challenging decisions regarding imaging patients with pre-existing devices where MRI is required to diagnose and manage a potentially life threatening or serious scenario. A range of other devices including ICDs, biventricular devices, and implantable physiologic monitors as well as guidance of medical procedures using MRI technology will require further biomedical device design changes and testing. The development and implementation of cardiac MR

  5. Antimyosin antibody cardiac imaging: Its role in the diagnosis of myocarditis

    SciTech Connect

    Dec, G.W.; Palacios, I.; Yasuda, T.; Fallon, J.T.; Khaw, B.A.; Strauss, H.W.; Haber, E. )

    1990-07-01

    Right ventricular endomyocardial biopsy currently remains the procedure of choice for identifying patients with symptomatic heart failure due to myocarditis from the larger population with idiopathic dilated cardiomyopathy. Despite its specificity, the sensitivity of right ventricular biopsy remains uncertain because of the focal or multifocal nature of the disease. Because myocyte necrosis is an obligate component of myocarditis, the use of indium-111 antimyosin imaging was evaluated in 82 patients with suspected myocarditis. Seventy-four patients had dilated cardiomyopathy of less than 1 year's duration (mean left ventricular ejection fraction 0.30 +/- 0.02); eight patients had normal left ventricular function (mean ejection fraction 0.59 +/- 0.03). Symptoms at presentation included congestive heart failure (92%), chest pain mimicking myocardial infarction (6%) and life-threatening ventricular tachyarrhythmias (2%). All patients underwent planar and single photon emission computed tomographic (SPECT) cardiac imaging after injection of indium-111-labeled antimyosin antibody fragments and right ventricular biopsy within 48 h of imaging. Antimyosin images were interpreted as either abnormal or normal and correlated with biopsy results. On the basis of the right ventricular histologic examination, the sensitivity of antimyosin imaging was 83%, specificity 53% and predictive value of a normal scan 92%. Improvement in left ventricular function occurred within 6 months of treatment in 54% of patients with an abnormal antimyosin scan compared with 18% of those with a normal scan (p less than 0.01). Antimyosin cardiac imaging may be useful for the initial evaluation of patients with dilated and nondilated cardiomyopathy and clinically suspected myocarditis.

  6. Impact of cardiac magnet resonance imaging on management of ventricular septal rupture after acute myocardial infarction

    PubMed Central

    Gassenmaier, Tobias; Gorski, Armin; Aleksic, Ivan; Deubner, Nikolas; Weidemann, Frank; Beer, Meinrad

    2013-01-01

    A 74-year-old man was admitted to the cardiac catheterization laboratory with acute myocardial infarction. After successful angioplasty and stent implantation into the right coronary artery, he developed cardiogenic shock the following day. Echocardiography showed ventricular septal rupture. Cardiac magnet resonance imaging (MRI) was performed on the critically ill patient and provided detailed information on size and localization of the ruptured septum by the use of fast MRI sequences. Moreover, the MRI revealed that the ventricular septal rupture was within the myocardial infarction area, which was substantially larger than the rupture. As the patient’s condition worsened, he was intubated and had intra-aortic balloon pump implanted, and extracorporeal membrane oxygenation was initiated. During the following days, the patient’s situation improved, and surgical correction of the ventricular septal defect could successfully be performed. To the best of our knowledge, this case report is the first description of postinfarction ventricular septal rupture by the use of cardiac MRI in an intensive care patient with cardiogenic shock and subsequent successful surgical repair. PMID:23710303

  7. Resolving Fine Cardiac Structures in Rats with High-Resolution Diffusion Tensor Imaging.

    PubMed

    Teh, Irvin; McClymont, Darryl; Burton, Rebecca A B; Maguire, Mahon L; Whittington, Hannah J; Lygate, Craig A; Kohl, Peter; Schneider, Jürgen E

    2016-01-01

    Cardiac architecture is fundamental to cardiac function and can be assessed non-invasively with diffusion tensor imaging (DTI). Here, we aimed to overcome technical challenges in ex vivo DTI in order to extract fine anatomical details and to provide novel insights in the 3D structure of the heart. An integrated set of methods was implemented in ex vivo rat hearts, including dynamic receiver gain adjustment, gradient system scaling calibration, prospective adjustment of diffusion gradients, and interleaving of diffusion-weighted and non-diffusion-weighted scans. Together, these methods enhanced SNR and spatial resolution, minimised orientation bias in diffusion-weighting, and reduced temperature variation, enabling detection of tissue structures such as cell alignment in atria, valves and vessels at an unprecedented level of detail. Improved confidence in eigenvector reproducibility enabled tracking of myolaminar structures as a basis for segmentation of functional groups of cardiomyocytes. Ex vivo DTI facilitates acquisition of high quality structural data that complements readily available in vivo cardiac functional and anatomical MRI. The improvements presented here will facilitate next generation virtual models integrating micro-structural and electro-mechanical properties of the heart. PMID:27466029

  8. Resolving Fine Cardiac Structures in Rats with High-Resolution Diffusion Tensor Imaging

    PubMed Central

    Teh, Irvin; McClymont, Darryl; Burton, Rebecca A. B.; Maguire, Mahon L.; Whittington, Hannah J.; Lygate, Craig A.; Kohl, Peter; Schneider, Jürgen E.

    2016-01-01

    Cardiac architecture is fundamental to cardiac function and can be assessed non-invasively with diffusion tensor imaging (DTI). Here, we aimed to overcome technical challenges in ex vivo DTI in order to extract fine anatomical details and to provide novel insights in the 3D structure of the heart. An integrated set of methods was implemented in ex vivo rat hearts, including dynamic receiver gain adjustment, gradient system scaling calibration, prospective adjustment of diffusion gradients, and interleaving of diffusion-weighted and non-diffusion-weighted scans. Together, these methods enhanced SNR and spatial resolution, minimised orientation bias in diffusion-weighting, and reduced temperature variation, enabling detection of tissue structures such as cell alignment in atria, valves and vessels at an unprecedented level of detail. Improved confidence in eigenvector reproducibility enabled tracking of myolaminar structures as a basis for segmentation of functional groups of cardiomyocytes. Ex vivo DTI facilitates acquisition of high quality structural data that complements readily available in vivo cardiac functional and anatomical MRI. The improvements presented here will facilitate next generation virtual models integrating micro-structural and electro-mechanical properties of the heart. PMID:27466029

  9. Myocardial Fibrosis and Left Ventricular Dysfunction in Duchenne Muscular Dystrophy Carriers Using Cardiac Magnetic Resonance Imaging.

    PubMed

    Lang, Sean M; Shugh, Svetlana; Mazur, Wojciech; Sticka, Joshua J; Rattan, Mantosh S; Jefferies, John L; Taylor, Michael D

    2015-10-01

    The goal of our study was to characterize the degree of myocardial fibrosis and left ventricular dysfunction in our cohort of Duchenne muscular dystrophy (DMD) carriers using cardiac magnetic resonance imaging (CMR). Seventy percent of males with DMD have mothers who are carriers of the Xp21 mutation. Carrier phenotypic characteristics range from asymptomatic to left ventricular (LV) dysfunction and cardiomyopathy. The true prevalence of cardiac involvement in DMD carriers is unknown. We performed a retrospective observational study. All female DMD carriers who underwent clinical CMR studies at Cincinnati Children's Hospital Medical Center from December 6, 2006, to August 28, 2013, were evaluated. Patients underwent standard CMR assessment with LV function assessment and late gadolinium enhancement (LGE). In addition, offline feature tracking strain analysis was performed on the basal, mid, and apical short axis. Twenty-two patients were studied, of which 20 underwent adequate testing for myocardial LGE. Four of 22 patients (18 %) were found to have LV dysfunction (ejection fraction <55 %). Seven of 20 DMD carriers (35 %) were found to have LGE. The patients with evidence of LGE had an overall trend to lower absolute deformation parameters; however, this did not meet statistical significance when correcting for multiple comparisons. Our study demonstrates a high rate of LGE as well as LV dysfunction in DMD carriers. Cardiovascular and musculoskeletal symptoms were not statistically different between those with and without cardiac involvement. This study demonstrates the importance of surveillance CMR evaluation of DMD carriers. PMID:25976773

  10. LBM-EP: Lattice-Boltzmann method for fast cardiac electrophysiology simulation from 3D images.

    PubMed

    Rapaka, S; Mansi, T; Georgescu, B; Pop, M; Wright, G A; Kamen, A; Comaniciu, Dorin

    2012-01-01

    Current treatments of heart rhythm troubles require careful planning and guidance for optimal outcomes. Computational models of cardiac electrophysiology are being proposed for therapy planning but current approaches are either too simplified or too computationally intensive for patient-specific simulations in clinical practice. This paper presents a novel approach, LBM-EP, to solve any type of mono-domain cardiac electrophysiology models at near real-time that is especially tailored for patient-specific simulations. The domain is discretized on a Cartesian grid with a level-set representation of patient's heart geometry, previously estimated from images automatically. The cell model is calculated node-wise, while the transmembrane potential is diffused using Lattice-Boltzmann method within the domain defined by the level-set. Experiments on synthetic cases, on a data set from CESC'10 and on one patient with myocardium scar showed that LBM-EP provides results comparable to an FEM implementation, while being 10 - 45 times faster. Fast, accurate, scalable and requiring no specific meshing, LBM-EP paves the way to efficient and detailed models of cardiac electrophysiology for therapy planning. PMID:23286029

  11. X-ray and magnetic resonance imaging fusion for cardiac resynchronization therapy.

    PubMed

    Choi, Jinwoo; Radau, Perry; Xu, Robert; Wright, Graham A

    2016-07-01

    Cardiac Resynchronization Therapy (CRT) can effectively treat left ventricle (LV) driven Heart Failure (HF). However, 30% of the CRT recipients do not experience symptomatic benefit. Recent studies show that the CRT response rate can reach 95% when the LV pacing lead is placed at an optimal site at a region of maximal LV dyssynchrony and away from myocardial scars. Cardiac Magnetic Resonance (CMR) can identify the optimal site in three dimensions (3D). 3D CMR data can be registered to clinical standard x-ray fluoroscopy to achieve an optimal pacing of the LV. We have developed a 3D CMR to 2D x-ray image registration method for CRT procedures. We have employed the LV pacing lead on x-ray images and coronary sinus on MR data as landmarks. The registration method makes use of a guidewire simulation algorithm, edge based image registration technique and x-ray C-arm tracking to register the coronary sinus and pacing lead landmarks. PMID:27025953

  12. Important advances in technology and unique applications related to cardiac magnetic resonance imaging.

    PubMed

    Ghosn, Mohamad G; Shah, Dipan J

    2014-01-01

    Cardiac magnetic resonance has become a well-established imaging modality and is considered the gold standard for myocardial tissue viability assessment and ventricular volumes quantification. Recent technological hardware and software advancements in magnetic resonance imaging technology have allowed the development of new methods that can improve clinical cardiovascular diagnosis and prognosis. The advent of a new generation of higher magnetic field scanners can be beneficial to various clinical applications. Also, the development of faster acquisition techniques have allowed mapping of the magnetic relaxation properties T1, T2, and T2* in the myocardium that can be used to quantify myocardial diffuse fibrosis, determine the presence of edema or inflammation, and measure iron within the myocardium, respectively. Another recent major advancement in CMR has been the introduction of three-dimension (3D) phase contrast imaging, also known as 4D flow. The following review discusses key advances in cardiac magnetic resonance technology and their potential to improve clinical cardiovascular diagnosis and outcomes. PMID:25574343

  13. Mechanistic molecular imaging of cardiac cell therapy for ischemic heart disease.

    PubMed

    Yu, Qiujun; Fan, Weiwei; Cao, Feng

    2013-10-01

    Cell-based myocardial regeneration has emerged as a promising therapeutic option for ischemic heart disease, though not yet at the level of routine clinical utility. Despite the encouraging results from initial preclinical studies that have demonstrated improved function and reduced infarct size of the ischemic myocardium following several candidate cell transplantation, the beneficial effects and molecular mechanisms of cardiac cell therapy are still unclear in clinical applications to date, and much remains to be optimized. To improve engraftment, accurate methods are required for tracking cell fate and quantifying functional outcome. In the present review, we summarized the current status and challenges of cardiac cell therapy for ischemic heart disease and discussed the strengths and limitations of currently available in vivo imaging techniques with special focus on the newly developed multimodality approaches for assessing the efficacy of engrafted donor cells. We also addressed the hurdles these imaging modalities are facing, including issues regarding immunogenicity and tumorigenicity of transplanted stem cells, and provided some the future perspectives on stem cell imaging.

  14. Important advances in technology and unique applications related to cardiac magnetic resonance imaging.

    PubMed

    Ghosn, Mohamad G; Shah, Dipan J

    2014-01-01

    Cardiac magnetic resonance has become a well-established imaging modality and is considered the gold standard for myocardial tissue viability assessment and ventricular volumes quantification. Recent technological hardware and software advancements in magnetic resonance imaging technology have allowed the development of new methods that can improve clinical cardiovascular diagnosis and prognosis. The advent of a new generation of higher magnetic field scanners can be beneficial to various clinical applications. Also, the development of faster acquisition techniques have allowed mapping of the magnetic relaxation properties T1, T2, and T2* in the myocardium that can be used to quantify myocardial diffuse fibrosis, determine the presence of edema or inflammation, and measure iron within the myocardium, respectively. Another recent major advancement in CMR has been the introduction of three-dimension (3D) phase contrast imaging, also known as 4D flow. The following review discusses key advances in cardiac magnetic resonance technology and their potential to improve clinical cardiovascular diagnosis and outcomes.

  15. Automated detection of the left ventricular region in gated nuclear cardiac imaging.

    PubMed

    Boudraa, A E; Arzi, M; Sau, J; Champier, J; Hadj-Moussa, S; Besson, J E; Sappey-Marinier, D; Itti, R; Mallet, J J

    1996-04-01

    An approach to automated outlining the left ventricular contour and its bounded area in gated isotopic ventriculography is proposed. Its purpose is to determine the ejection fraction (EF), an important parameter for measuring cardiac function. The method uses a modified version of the fuzzy C-means (MFCM) algorithm and a labeling technique. The MFCM algorithm is applied to the end diastolic (ED) frame and then the (FCM) is applied to the remaining images in a "box" of interest. The MFCM generates a number of fuzzy clusters. Each cluster is a substructure of the heart (left ventricle,...). A cluster validity index to estimate the optimum clusters number present in image data point is used. This index takes account of the homogeneity in each cluster and is connected to the geometrical property of data set. The labeling is only performed to achieve the detection process in the ED frame. Since the left ventricle (LV) cluster has the greatest area of the cardiac images sequence in ED phase, a framing operation is performed to obtain, automatically, the "box" enclosing the LV cluster. THe EF assessed in 50 patients by the proposed method and a semi-automatic one, routinely used, are presented. A good correlation between the two methods EF values is obtained (R = 0.93). The LV contour found has been judged very satisfactory by a team of trained clinicians. PMID:8626193

  16. Stress cardiac MR imaging: the role of stress functional assessment and perfusion imaging in the evaluation of ischemic heart disease.

    PubMed

    Al Sayari, Saeed; Kopp, Sebastien; Bremerich, Jens

    2015-03-01

    Stress cardiac magnetic resonance imaging can provide valuable information for the diagnosis and management of ischemic heart disease (IHD). It plays an important role in the initial diagnosis in patients with acute chest pain, in the diagnosis of complications post myocardial infarction (MI), in the assessment of the right ventricle after an acute MI, to detect complications due to or after interventions, in prediction of myocardial recovery, to detect inducible ischemia in patients with known IHD, in differentiating ischemic from non-ischemic dilated cardiomyopathy, and in risk stratification.

  17. Stress cardiac MR imaging: the role of stress functional assessment and perfusion imaging in the evaluation of ischemic heart disease.

    PubMed

    Al Sayari, Saeed; Kopp, Sebastien; Bremerich, Jens

    2015-03-01

    Stress cardiac magnetic resonance imaging can provide valuable information for the diagnosis and management of ischemic heart disease (IHD). It plays an important role in the initial diagnosis in patients with acute chest pain, in the diagnosis of complications post myocardial infarction (MI), in the assessment of the right ventricle after an acute MI, to detect complications due to or after interventions, in prediction of myocardial recovery, to detect inducible ischemia in patients with known IHD, in differentiating ischemic from non-ischemic dilated cardiomyopathy, and in risk stratification. PMID:25727000

  18. Improved myocardial strain measured by strain-encoded magnetic resonance imaging in a patient with cardiac sarcoidosis.

    PubMed

    Nakano, Shintaro; Kimura, Fumiko; Osman, Nael; Sugi, Keiki; Tanno, Jun; Uchida, Yoshitaka; Shiono, Ayako; Senbonmatsu, Takaaki; Nishimura, Shigeyuki

    2013-11-01

    A woman aged 64 years with cardiac sarcoidosis responded favourably to corticosteroid therapy in terms of recovered longitudinal myocardial strain, as evaluated by strain-encoded magnetic resonance imaging (SENC-MRI). In contrast, circumferential myocardial strain and late gadolinium enhancement demonstrated minimal improvement, suggesting relatively advanced pathology of the myocardial middle layer. We propose SENC-MRI as a marker of disease at an early stage of cardiac sarcoidosis.

  19. Cardiac Amyloidosis: Typical Imaging Findings and Diffuse Myocardial Damage Demonstrated by Delayed Contrast-Enhanced MRI

    SciTech Connect

    Sueyoshi, Eijun Sakamoto, Ichiro; Okimoto, Tomoaki; Hayashi, Kuniaki; Tanaka, Kyouei; Toda, Genji

    2006-08-15

    Amyloidosis is a rare systemic disease. However, involvement of the heart is a common finding and is the most frequent cause of death in amyloidosis. We report the sonographic, scintigraphic, and MRI features of a pathologically proven case of cardiac amyloidosis. Delayed contrast-enhanced MR images, using an inversion recovery prepped gradient-echo sequence, revealed diffuse enhancement in the wall of both left and right ventricles. This enhancement suggested expansion of the extracellular space of the myocardium caused by diffuse myocardial necrosis secondary to deposition of amyloid.

  20. Cardiac imaging: New technologies and clinical applications. Vol. 17, No. 1

    SciTech Connect

    Kotler, M.N.; Steiner, R.M.

    1986-01-01

    Imaging of the cardiovascular system has made much progress during the past several years. This book addresses the issues surrounding development and clinical utilization of techniques for diagnosis in valvular, coronary artery, and congenital heart disease. Included among the evaluation modalities are Doppler ultrasound, contrast 2-D echocardiography, thallium scintigraphy, nuclear magnetic resonance and emission tomography (CT, ECT, SPECT, PET). Advantages and disadvantages of these modes are discussed, and compared to each other and to older methods such as cardiac catheterization and angiography. Consideration is given to the use of the computer as an aid to the cardiologist.

  1. Functional Cardiac Magnetic Resonance Imaging (MRI) in the Assessment of Myocardial Viability and Perfusion

    PubMed Central

    2003-01-01

    Executive Summary Objective The objective of this health technology policy assessment was to determine the effectiveness safety and cost-effectiveness of using functional cardiac magnetic resonance imaging (MRI) for the assessment of myocardial viability and perfusion in patients with coronary artery disease and left ventricular dysfunction. Results Functional MRI has become increasingly investigated as a noninvasive method for assessing myocardial viability and perfusion. Most patients in the published literature have mild to moderate impaired LV function. It is possible that the severity of LV dysfunction may be an important factor that can alter the diagnostic accuracy of imaging techniques. There is some evidence of comparable or better performance of functional cardiac MRI for the assessment of myocardial viability and perfusion compared with other imaging techniques. However limitations to most of the studies included: Functional cardiac MRI studies that assess myocardial viability and perfusion have had small sample sizes. Some studies assessed myocardial viability/perfusion in patients who had already undergone revascularization, or excluded patients with a prior MI (Schwitter et al., 2001). Lack of explicit detail of patient recruitment. Patients with LVEF >35%. Interstudy variability in post MI imaging time(including acute or chronic MI), when patients with a prior MI were included. Poor interobserver agreement (kappa statistic) in the interpretation of the results. Traditionally, 0.80 is considered “good”. Cardiac MRI measurement of myocardial perfusion to as an adjunct tool to help diagnose CAD (prior to a definitive coronary angiography) has also been examined in some studies, with methodological limitations, yielding comparable results. Many studies examining myocardial viability and perfusion report on the accuracy of imaging methods with limited data on long-term patient outcome and management. Kim et al. (2000) revealed that the transmural

  2. Image Cytometry Data From Breast Lesions Analyzed using Hybrid Networks.

    PubMed

    Mat Sakim, H A; Mat Isa, N A; G Naguib, Raouf; Sherbet, Gajanan

    2005-01-01

    The treatment and therapy to be administered on breast cancer patients are dependent on the stage of the disease at time of diagnosis. It is therefore crucial to determine the stage at the earliest time possible. Tumor dissemination to axillary lymph nodes has been regarded as an indication of tumor aggression, thus the stage of the disease. Neural networks have been employed in many applications including breast cancer prognosis. The performance of the networks have often been quoted based on accuracy and mean squared error. In this paper, the performance of hybrid networks based on Multilayer Perceptron and Radial Basis Function networks to predict axillary lymph node involvement have been investigated. A measurement of how confident the networks are with respect to the results produced is also proposed. The input layer of the networks include four image cytometry features extracted from fine needle aspiration of breast lesions. The highest accuracy achieved by the hybrid networks was 69% only. However, most of the correctly predicted cases had a high confidence level.

  3. Register cardiac fiber orientations from 3D DTI volume to 2D ultrasound image of rat hearts

    PubMed Central

    Qin, Xulei; Wang, Silun; Shen, Ming; Zhang, Xiaodong; Lerakis, Stamatios; Wagner, Mary B.; Fei, Baowei

    2015-01-01

    Two-dimensional (2D) ultrasound or echocardiography is one of the most widely used examinations for the diagnosis of cardiac diseases. However, it only supplies the geometric and structural information of the myocardium. In order to supply more detailed microstructure information of the myocardium, this paper proposes a registration method to map cardiac fiber orientations from three-dimensional (3D) magnetic resonance diffusion tensor imaging (MR-DTI) volume to the 2D ultrasound image. It utilizes a 2D/3D intensity based registration procedure including rigid, log-demons, and affine transformations to search the best similar slice from the template volume. After registration, the cardiac fiber orientations are mapped to the 2D ultrasound image via fiber relocations and reorientations. This method was validated by six images of rat hearts ex vivo. The evaluation results indicated that the final Dice similarity coefficient (DSC) achieved more than 90% after geometric registrations; and the inclination angle errors (IAE) between the mapped fiber orientations and the gold standards were less than 15 degree. This method may provide a practical tool for cardiologists to examine cardiac fiber orientations on ultrasound images and have the potential to supply additional information for diagnosis of cardiac diseases. PMID:26855466

  4. Register cardiac fiber orientations from 3D DTI volume to 2D ultrasound image of rat hearts

    NASA Astrophysics Data System (ADS)

    Qin, Xulei; Wang, Silun; Shen, Ming; Zhang, Xiaodong; Lerakis, Stamatios; Wagner, Mary B.; Fei, Baowei

    2015-03-01

    Two-dimensional (2D) ultrasound or echocardiography is one of the most widely used examinations for the diagnosis of cardiac diseases. However, it only supplies the geometric and structural information of the myocardium. In order to supply more detailed microstructure information of the myocardium, this paper proposes a registration method to map cardiac fiber orientations from three-dimensional (3D) magnetic resonance diffusion tensor imaging (MR-DTI) volume to the 2D ultrasound image. It utilizes a 2D/3D intensity based registration procedure including rigid, log-demons, and affine transformations to search the best similar slice from the template volume. After registration, the cardiac fiber orientations are mapped to the 2D ultrasound image via fiber relocations and reorientations. This method was validated by six images of rat hearts ex vivo. The evaluation results indicated that the final Dice similarity coefficient (DSC) achieved more than 90% after geometric registrations; and the inclination angle errors (IAE) between the mapped fiber orientations and the gold standards were less than 15 degree. This method may provide a practical tool for cardiologists to examine cardiac fiber orientations on ultrasound images and have the potential to supply additional information for diagnosis of cardiac diseases.

  5. Super-resolution fluorescence imaging to study cardiac biophysics: α-actinin distribution and Z-disk topologies in optically thick cardiac tissue slices.

    PubMed

    Hou, Yufeng; Crossman, David J; Rajagopal, Vijay; Baddeley, David; Jayasinghe, Isuru; Soeller, Christian

    2014-08-01

    A major motivation for the use of super-resolution imaging methods in the investigation of cardiac biophysics has been the insight from biophysical considerations and detailed mathematical modeling that the spatial structure and protein organisation at the scale of nanometres can have enormous implications for calcium signalling in cardiac muscle. We illustrate the use of dSTORM based super-resolution in optically thick (∼10 μm) tissue slices of rat ventricular tissue to visualize proteins at the cardiac Z-disk and compare those images with confocal (diffraction-limited) as well as electron microscopy (EM) data which still provides a benchmark in terms of resolution. α-actinin is an abundant protein target that effectively defines the Z-disk in striated muscle and provides a reference structure for other proteins at the Z-line and the transverse tubules. Using super-resolution imaging α-actinin labelling provides very detailed outlines of the contractile machinery which we have used to study the properties of Z-disks and the distribution of α-actinin itself. We determined the local diameters of the myo-fibrillar and non-myofibrillar space using α-actinin labelling. Comparison between confocal and super-resolution based myofibrillar masks suggested that super-resolution data was able to segment myofibrils accurately while confocal approaches were not always able to distinguish neighbouring myofibrillar bundles which resulted in overestimated diameters. The increased resolution of super-resolution methods provides qualitatively new information to improve our understanding of cardiac biophysics. Nevertheless, conventional diffraction-limited imaging still has an important role to play which we illustrate with correlative confocal and super-resolution data.

  6. Real-time dynamic display of registered 4D cardiac MR and ultrasound images using a GPU

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Huang, X.; Eagleson, R.; Guiraudon, G.; Peters, T. M.

    2007-03-01

    In minimally invasive image-guided surgical interventions, different imaging modalities, such as magnetic resonance imaging (MRI), computed tomography (CT), and real-time three-dimensional (3D) ultrasound (US), can provide complementary, multi-spectral image information. Multimodality dynamic image registration is a well-established approach that permits real-time diagnostic information to be enhanced by placing lower-quality real-time images within a high quality anatomical context. For the guidance of cardiac procedures, it would be valuable to register dynamic MRI or CT with intraoperative US. However, in practice, either the high computational cost prohibits such real-time visualization of volumetric multimodal images in a real-world medical environment, or else the resulting image quality is not satisfactory for accurate guidance during the intervention. Modern graphics processing units (GPUs) provide the programmability, parallelism and increased computational precision to begin to address this problem. In this work, we first outline our research on dynamic 3D cardiac MR and US image acquisition, real-time dual-modality registration and US tracking. Then we describe image processing and optimization techniques for 4D (3D + time) cardiac image real-time rendering. We also present our multimodality 4D medical image visualization engine, which directly runs on a GPU in real-time by exploiting the advantages of the graphics hardware. In addition, techniques such as multiple transfer functions for different imaging modalities, dynamic texture binding, advanced texture sampling and multimodality image compositing are employed to facilitate the real-time display and manipulation of the registered dual-modality dynamic 3D MR and US cardiac datasets.

  7. Detection of Left Ventricular Regional Dysfunction and Myocardial Abnormalities Using Complementary Cardiac Magnetic Resonance Imaging in Patients with Systemic Sclerosis without Cardiac Symptoms: A Pilot Study.

    PubMed

    Kobayashi, Yasuyuki; Kobayashi, Hitomi; T Giles, Jon; Yokoe, Isamu; Hirano, Masaharu; Nakajima, Yasuo; Takei, Masami

    2016-01-01

    Objective We sought to detect the presence of left ventricular regional dysfunction and myocardial abnormalities in systemic sclerosis (SSc) patients without cardiac symptoms using a complementary cardiac magnetic resonance (CMR) imaging approach. Methods Consecutive patients with SSc without cardiac symptoms and healthy controls underwent CMR on a 1.5 T scanner. The peak systolic regional function in the circumferential and radial strain (Ecc, % and Err, %) were calculated using a feature tracking analysis on the mid-left ventricular slices obtained with cine MRI. In addition, we investigated the myocardial characteristics by contrast MRI. Pharmacological stress and rest perfusion scans were performed to assess perfusion defect (PD) due to micro- or macrovascular impairment, and late gadolinium enhancement (LGE) images were obtained for the assessment of myocarditis and/or fibrosis. Results We compared 15 SSc patients with 10 healthy controls. No statistically significant differences were observed in the baseline characteristics between the patients and healthy controls. The mean peak Err and Ecc of all segments was significantly lower in the patients than the controls (p=0.011 and p=0.003, respectively). Four patients with LGE (28.6%) and seven patients with PD (50.0%) were observed. PD was significantly associated with digital ulcers (p=0.005). Utilizing a linear regression model, the presence of myocardial LGE was significantly associated with the peak Ecc (p=0.024). After adjusting for age, the association between myocardial LGE and the peak Ecc was strengthened. Conclusion A subclinical myocardial involvement, as detected by CMR, was prevalent in the SSc patients without cardiac symptoms. Regional dysfunction might predict the myocardial abnormalities observed in SSc patients without cardiac symptoms.

  8. 3D high-density localization microscopy using hybrid astigmatic/ biplane imaging and sparse image reconstruction.

    PubMed

    Min, Junhong; Holden, Seamus J; Carlini, Lina; Unser, Michael; Manley, Suliana; Ye, Jong Chul

    2014-11-01

    Localization microscopy achieves nanoscale spatial resolution by iterative localization of sparsely activated molecules, which generally leads to a long acquisition time. By implementing advanced algorithms to treat overlapping point spread functions (PSFs), imaging of densely activated molecules can improve the limited temporal resolution, as has been well demonstrated in two-dimensional imaging. However, three-dimensional (3D) localization of high-density data remains challenging since PSFs are far more similar along the axial dimension than the lateral dimensions. Here, we present a new, high-density 3D imaging system and algorithm. The hybrid system is implemented by combining astigmatic and biplane imaging. The proposed 3D reconstruction algorithm is extended from our state-of-the art 2D high-density localization algorithm. Using mutual coherence analysis of model PSFs, we validated that the hybrid system is more suitable than astigmatic or biplane imaging alone for 3D localization of high-density data. The efficacy of the proposed method was confirmed via simulation and real data of microtubules. Furthermore, we also successfully demonstrated fluorescent-protein-based live cell 3D localization microscopy with a temporal resolution of just 3 seconds, capturing fast dynamics of the endoplasmic recticulum.

  9. Improving low-dose cardiac CT images using 3D sparse representation based processing

    NASA Astrophysics Data System (ADS)

    Shi, Luyao; Chen, Yang; Luo, Limin

    2015-03-01

    Cardiac computed tomography (CCT) has been widely used in diagnoses of coronary artery diseases due to the continuously improving temporal and spatial resolution. When helical CT with a lower pitch scanning mode is used, the effective radiation dose can be significant when compared to other radiological exams. Many methods have been developed to reduce radiation dose in coronary CT exams including high pitch scans using dual source CT scanners and step-and-shot scanning mode for both single source and dual source CT scanners. Additionally, software methods have also been proposed to reduce noise in the reconstructed CT images and thus offering the opportunity to reduce radiation dose while maintaining the desired diagnostic performance of a certain imaging task. In this paper, we propose that low-dose scans should be considered in order to avoid the harm from accumulating unnecessary X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. Accordingly, in this paper, a 3D dictionary representation based image processing method is proposed to reduce CT image noise. Information on both spatial and temporal structure continuity is utilized in sparse representation to improve the performance of the image processing method. Clinical cases were used to validate the proposed method.

  10. Value of blood-pool subtraction in cardiac indium-111-labeled platelet imaging

    SciTech Connect

    Machac, J.; Vallabhajosula, S.; Goldman, M.E.; Goldsmith, S.J.; Palestro, C.; Strashun, A.; Vaquer, R.; Phillips, R.A.; Fuster, V. )

    1989-09-01

    Blood-pool subtraction has been proposed to enhance {sup 111}In-labeled platelet imaging of intracardiac thrombi. We tested the accuracy of labeled platelet imaging, with and without blood-pool subtraction, in ten subjects with cardiac thrombi of varying age, eight with endocarditis being treated with antimicrobial therapy and ten normal controls. Imaging was performed early after labeled platelet injection (24 hr or less) and late (48 hr or more). Blood-pool subtraction was carried out. All images were graded subjectively by four experienced, blinded readers. Detection accuracy was measured by the sensitivity at three fixed levels of specificity estimated from receiver operator characteristic curve analysis and tested by three-way analysis of variance. Detection accuracy was generally improved on delayed images. Blood-pool subtraction did not improve accuracy. Although blood-pool subtraction increased detection sensitivity, this was offset by decreased specificity. For this population studied, blood-pool subtraction did not improve subjective detection of abnormal platelet deposition by 111In platelet imaging.

  11. The Effect of Acute Coronary Perfusion Change on Cardiac Function measured by Shear Wave Elasticity Imaging

    PubMed Central

    Vejdani-Jahromi, Maryam; Kiplagat, Annette; Trahey, Gregg E.; Wolf, Patrick D.

    2016-01-01

    The possibility of measuring cardiac function noninvasively has generated wide interest in elastography imaging techniques. Shear Wave Elasticity Imaging (SWEI) is an ultrasound-based elastography technique used to measure stiffness of tissues. While this technique has been studied extensively in static homogenous tissues such as liver, breast or prostate, there is still a significant need to study its capabilities to measure cardiac stiffness and function. In this research, we have studied the potential of SWEI to evaluate the coronary perfusion pressure effect on systolic and diastolic stiffness referred to as elastance and compliance of the heart. Five isolated rabbit hearts were used in this study in a Langendorff preparation. SWEI measurements of stiffness were recorded in two steps. In the first step, coronary perfusion was set to normal and then was reduced to half-normal. After 40 minutes of half-normal perfusion, it was returned to normal perfusion for the second step. SWEI velocity decreased from 6.003 m/s to 4.713 m/s in systole and from 1.948 m/s to 1.507 m/s in diastole in the first step. During the second step raising the perfusion to normal, SWEI stiffness showed an increase from 3.760 m/s to 5.468 m/s in systole and from 1.678 m/s to 2.156 m/s during diastole. Our results show that SWEI measurements of stiffness can characterize the cross talk between coronary perfusion and cardiac stiffness and also has the potential to measure compliance and elastance of the heart in systole and diastole. PMID:25571133

  12. Correlation-based discrimination between cardiac tissue and blood for segmentation of 3D echocardiographic images

    NASA Astrophysics Data System (ADS)

    Saris, Anne E. C. M.; Nillesen, Maartje M.; Lopata, Richard G. P.; de Korte, Chris L.

    2013-03-01

    Automated segmentation of 3D echocardiographic images in patients with congenital heart disease is challenging, because the boundary between blood and cardiac tissue is poorly defined in some regions. Cardiologists mentally incorporate movement of the heart, using temporal coherence of structures to resolve ambiguities. Therefore, we investigated the merit of temporal cross-correlation for automated segmentation over the entire cardiac cycle. Optimal settings for maximum cross-correlation (MCC) calculation, based on a 3D cross-correlation based displacement estimation algorithm, were determined to obtain the best contrast between blood and myocardial tissue over the entire cardiac cycle. Resulting envelope-based as well as RF-based MCC values were used as additional external force in a deformable model approach, to segment the left-ventricular cavity in entire systolic phase. MCC values were tested against, and combined with, adaptive filtered, demodulated RF-data. Segmentation results were compared with manually segmented volumes using a 3D Dice Similarity Index (3DSI). Results in 3D pediatric echocardiographic images sequences (n = 4) demonstrate that incorporation of temporal information improves segmentation. The use of MCC values, either alone or in combination with adaptive filtered, demodulated RF-data, resulted in an increase of the 3DSI in 75% of the cases (average 3DSI increase: 0.71 to 0.82). Results might be further improved by optimizing MCC-contrast locally, in regions with low blood-tissue contrast. Reducing underestimation of the endocardial volume due to MCC processing scheme (choice of window size) and consequential border-misalignment, could also lead to more accurate segmentations. Furthermore, increasing the frame rate will also increase MCC-contrast and thus improve segmentation.

  13. Hybrid Imaging for Extended Depth of Field Microscopy

    NASA Astrophysics Data System (ADS)

    Zahreddine, Ramzi Nicholas

    An inverse relationship exists in optical systems between the depth of field (DOF) and the minimum resolvable feature size. This trade-off is especially detrimental in high numerical aperture microscopy systems where resolution is pushed to the diffraction limit resulting in a DOF on the order of 500 nm. Many biological structures and processes of interest span over micron scales resulting in significant blurring during imaging. This thesis explores a two-step computational imaging technique known as hybrid imaging to create extended DOF (EDF) microscopy systems with minimal sacrifice in resolution. In the first step a mask is inserted at the pupil plane of the microscope to create a focus invariant system over 10 times the traditional DOF, albeit with reduced contrast. In the second step the contrast is restored via deconvolution. Several EDF pupil masks from the literature are quantitatively compared in the context of biological microscopy. From this analysis a new mask is proposed, the incoherently partitioned pupil with binary phase modulation (IPP-BPM), that combines the most advantageous properties from the literature. Total variation regularized deconvolution models are derived for the various noise conditions and detectors commonly used in biological microscopy. State of the art algorithms for efficiently solving the deconvolution problem are analyzed for speed, accuracy, and ease of use. The IPP-BPM mask is compared with the literature and shown to have the highest signal-to-noise ratio and lowest mean square error post-processing. A prototype of the IPP-BPM mask is fabricated using a combination of 3D femtosecond glass etching and standard lithography techniques. The mask is compared against theory and demonstrated in biological imaging applications.

  14. Cardiac Magnetic Resonance Scar Imaging for Sudden Cardiac Death Risk Stratification in Patients with Non-Ischemic Cardiomyopathy

    PubMed Central

    Kim, Eun Kyoung; Chattranukulchai, Pairoj

    2015-01-01

    In patients with non-ischemic cardiomyopathy (NICM), risk stratification for sudden cardiac death (SCD) and selection of patients who would benefit from prophylactic implantable cardioverter-defibrillators remains challenging. We aim to discuss the evidence of cardiac magnetic resonance (CMR)-derived myocardial scar for the prediction of adverse cardiovascular outcomes in NICM. From the 15 studies analyzed, with a total of 2747 patients, the average prevalence of myocardial scar was 41%. In patients with myocardial scar, the risk for adverse cardiac events was more than 3-fold higher, and risk for arrhythmic events 5-fold higher, as compared to patients without scar. Based on the available observational, single center studies, CMR scar assessment may be a promising new tool for SCD risk stratification, which merits further investigation. PMID:26175568

  15. Spatiotemporal non-rigid image registration for 3D ultrasound cardiac motion estimation

    NASA Astrophysics Data System (ADS)

    Loeckx, D.; Ector, J.; Maes, F.; D'hooge, J.; Vandermeulen, D.; Voigt, J.-U.; Heidbüchel, H.; Suetens, P.

    2007-03-01

    We present a new method to evaluate 4D (3D + time) cardiac ultrasound data sets by nonrigid spatio-temporal image registration. First, a frame-to-frame registration is performed that yields a dense deformation field. The deformation field is used to calculate local spatiotemporal properties of the myocardium, such as the velocity, strain and strain rate. The field is also used to propagate particular points and surfaces, representing e.g. the endo-cardial surface over the different frames. As such, the 4D path of these point is obtained, which can be used to calculate the velocity by which the wall moves and the evolution of the local surface area over time. The wall velocity is not angle-dependent as in classical Doppler imaging, since the 4D data allows calculating the true 3D motion. Similarly, all 3D myocardium strain components can be estimated. Combined they result in local surface area or volume changes which van be color-coded as a measure of local contractability. A diagnostic method that strongly benefits from this technique is cardiac motion and deformation analysis, which is an important aid to quantify the mechanical properties of the myocardium.

  16. In vivo validation of cardiac output assessment in non-standard 3D echocardiographic images

    NASA Astrophysics Data System (ADS)

    Nillesen, M. M.; Lopata, R. G. P.; de Boode, W. P.; Gerrits, I. H.; Huisman, H. J.; Thijssen, J. M.; Kapusta, L.; de Korte, C. L.

    2009-04-01

    Automatic segmentation of the endocardial surface in three-dimensional (3D) echocardiographic images is an important tool to assess left ventricular (LV) geometry and cardiac output (CO). The presence of speckle noise as well as the nonisotropic characteristics of the myocardium impose strong demands on the segmentation algorithm. In the analysis of normal heart geometries of standardized (apical) views, it is advantageous to incorporate a priori knowledge about the shape and appearance of the heart. In contrast, when analyzing abnormal heart geometries, for example in children with congenital malformations, this a priori knowledge about the shape and anatomy of the LV might induce erroneous segmentation results. This study describes a fully automated segmentation method for the analysis of non-standard echocardiographic images, without making strong assumptions on the shape and appearance of the heart. The method was validated in vivo in a piglet model. Real-time 3D echocardiographic image sequences of five piglets were acquired in radiofrequency (rf) format. These ECG-gated full volume images were acquired intra-operatively in a non-standard view. Cardiac blood flow was measured simultaneously by an ultrasound transit time flow probe positioned around the common pulmonary artery. Three-dimensional adaptive filtering using the characteristics of speckle was performed on the demodulated rf data to reduce the influence of speckle noise and to optimize the distinction between blood and myocardium. A gradient-based 3D deformable simplex mesh was then used to segment the endocardial surface. A gradient and a speed force were included as external forces of the model. To balance data fitting and mesh regularity, one fixed set of weighting parameters of internal, gradient and speed forces was used for all data sets. End-diastolic and end-systolic volumes were computed from the segmented endocardial surface. The cardiac output derived from this automatic segmentation was

  17. Live dynamic OCT imaging of cardiac structure and function in mouse embryos with 43 Hz direct volumetric data acquisition

    NASA Astrophysics Data System (ADS)

    Wang, Shang; Singh, Manmohan; Lopez, Andrew L.; Wu, Chen; Raghunathan, Raksha; Schill, Alexander; Li, Jiasong; Larin, Kirill V.; Larina, Irina V.

    2016-03-01

    Efficient phenotyping of cardiac dynamics in live mouse embryos has significant implications on understanding of early mammalian heart development and congenital cardiac defects. Recent studies established optical coherence tomography (OCT) as a powerful tool for live embryonic heart imaging in various animal models. However, current four-dimensional (4D) OCT imaging of the beating embryonic heart largely relies on gated data acquisition or postacquisition synchronization, which brings errors when cardiac cycles lack perfect periodicity and is time consuming and computationally expensive. Here, we report direct 4D OCT imaging of the structure and function of cardiac dynamics in live mouse embryos achieved by employing a Fourier domain mode-locking swept laser source that enables ~1.5 MHz A-line rate. Through utilizing both forward and backward scans of a resonant mirror, we obtained a ~6.4 kHz frame rate, which allows for a direct volumetric data acquisition speed of ~43 Hz, around 20 times of the early-stage mouse embryonic heart rate. Our experiments were performed on mouse embryos at embryonic day 9.5. Time-resolved 3D cardiodynamics clearly shows the heart structure in motion. We present analysis of cardiac wall movement and its velocity from the primitive atrium and ventricle. Our results suggest that the combination of ultrahigh-speed OCT imaging with live embryo culture could be a useful embryonic heart phenotyping approach for mouse mutants modeling human congenital heart diseases.

  18. Impact of cardiac magnetic resonance imaging in non-ischemic cardiomyopathies

    PubMed Central

    Kalisz, Kevin; Rajiah, Prabhakar

    2016-01-01

    Non-ischemic cardiomyopathies include a wide spectrum of disease states afflicting the heart, whether a primary process or secondary to a systemic condition. Cardiac magnetic resonance imaging (CMR) has established itself as an important imaging modality in the evaluation of non-ischemic cardiomyopathies. CMR is useful in the diagnosis of cardiomyopathy, quantification of ventricular function, establishing etiology, determining prognosis and risk stratification. Technical advances and extensive research over the last decade have resulted in the accumulation of a tremendous amount of data with regards to the utility of CMR in these cardiomyopathies. In this article, we review CMR findings of various non-ischemic cardiomyopathies and focus on current literature investigating the clinical impact of CMR on risk stratification, treatment, and prognosis. PMID:26981210

  19. Imaging longitudinal cardiac strain on short-axis images using 3D HARP

    NASA Astrophysics Data System (ADS)

    Osman, Nael F.; Sampath, Smita; Prince, Jerry L.

    2000-04-01

    This paper presents a new method for measuring longitudinal strain of the heart using harmonic phase magnetic resonance imaging (HARP-MRI). The heart is tagged using 1-1 SPAMM at end-diastole with tagging surfaces parallel to the imaging plane. Two image sequences are acquired for a short-axis slice with two different encodings in the direction orthogonal to the imaging plane. A method to compute a sequence of longitudinal strain estimates from this data is described.

  20. Learning dynamic hybrid Markov random field for image labeling.

    PubMed

    Zhou, Quan; Zhu, Jun; Liu, Wenyu

    2013-06-01

    Using shape information has gained increasing concerns in the task of image labeling. In this paper, we present a dynamic hybrid Markov random field (DHMRF), which explicitly captures middle-level object shape and low-level visual appearance (e.g., texture and color) for image labeling. Each node in DHMRF is described by either a deformable template or an appearance model as visual prototype. On the other hand, the edges encode two types of intersections: co-occurrence and spatial layered context, with respect to the labels and prototypes of connected nodes. To learn the DHMRF model, an iterative algorithm is designed to automatically select the most informative features and estimate model parameters. The algorithm achieves high computational efficiency since a branch-and-bound schema is introduced to estimate model parameters. Compared with previous methods, which usually employ implicit shape cues, our DHMRF model seamlessly integrates color, texture, and shape cues to inference labeling output, and thus produces more accurate and reliable results. Extensive experiments validate its superiority over other state-of-the-art methods in terms of recognition accuracy and implementation efficiency on: 1) the MSRC 21-class dataset, and 2) the lotus hill institute 15-class dataset.

  1. Intraoperative 3D stereo visualization for image-guided cardiac ablation

    NASA Astrophysics Data System (ADS)

    Azizian, Mahdi; Patel, Rajni

    2011-03-01

    There are commercial products which provide 3D rendered volumes, reconstructed from electro-anatomical mapping and/or pre-operative CT/MR images of a patient's heart with tools for highlighting target locations for cardiac ablation applications. However, it is not possible to update the three-dimensional (3D) volume intraoperatively to provide the interventional cardiologist with more up-to-date feedback at each instant of time. In this paper, we describe the system we have developed for real-time three-dimensional stereo visualization for cardiac ablation. A 4D ultrasound probe is used to acquire and update a 3D image volume. A magnetic tracking device is used to track the distal part of the ablation catheter in real time and a master-slave robot-assisted system is developed for actuation of a steerable catheter. Three-dimensional ultrasound image volumes go through some processing to make the heart tissue and the catheter more visible. The rendered volume is shown in a virtual environment. The catheter can also be added as a virtual tool to this environment to achieve a higher update rate on the catheter's position. The ultrasound probe is also equipped with an EM tracker which is used for online registration of the ultrasound images and the catheter tracking data. The whole augmented reality scene can be shown stereoscopically to enhance depth perception for the user. We have used transthoracic echocardiography (TTE) instead of the conventional transoesophageal (TEE) or intracardiac (ICE) echocardiogram. A beating heart model has been used to perform the experiments. This method can be used both for diagnostic and therapeutic applications as well as training interventional cardiologists.

  2. Usefulness of cardiac meta-iodobenzylguanidine imaging to identify patients with chronic heart failure and left ventricular ejection fraction <35% at low risk for sudden cardiac death.

    PubMed

    Kawai, Tsutomu; Yamada, Takahisa; Tamaki, Shunsuke; Morita, Takashi; Furukawa, Yoshio; Iwasaki, Yusuke; Kawasaki, Masato; Kikuchi, Atsushi; Kondo, Takumi; Takahashi, Satoshi; Ishimi, Masashi; Hakui, Hideyuki; Ozaki, Tatsuhisa; Sato, Yoshihiro; Seo, Masahiro; Sakata, Yasushi; Fukunami, Masatake

    2015-06-01

    Patients with chronic heart failure (CHF) at risk of sudden cardiac death (SCD) are often treated with implantable cardiac defibrillators (ICDs). However, current criteria for device use that is based largely on left ventricular ejection fraction (LVEF) lead to many patients receiving ICDs that never deliver therapy. It is of clinical significance to identify patients who do not require ICDs. Although cardiac I-123 meta-iodobenzylguanidine (MIBG) imaging provides prognostic information about CHF, whether it can identify patients with CHF who do not require an ICD remains unclear. We studied 81 patients with CHF and LVEF <35%, assessed by cardiac MIBG imaging at enrollment. The heart-to-mediastinal ratio (H/M) in delayed images and washout rates were divided into 6 grades from 0 to 5, according to the degree of deviation from control values. The study patients were classified into 3 groups: low (1 to 4), intermediate (5 to 7), and high (8 to 10), according to the MIBG scores defined as the sum of the H/M and washout rate scores. Sixteen patients died of SCD during a follow-up period. Patients with low MIBG score had a significantly lower risk of SCD than those with intermediate and high scores (low [n = 19], 0%; intermediate [n = 37], 19%; high [n = 25], 36%; p = 0.001). The positive predictive value of low MIBG score for identifying patients without SCD was 100%. In conclusion, the MIBG score can identify patients with CHF and LVEF <35% who have low risk of developing SCD. PMID:25851796

  3. Three-dimensional magnetic resonance imaging overlay to assist with percutaneous transhepatic access at the time of cardiac catheterization.

    PubMed

    Whiteside, Wendy; Christensen, Jason; Zampi, Jeffrey D

    2015-01-01

    Multimodality image overlay is increasingly used for complex interventional procedures in the cardiac catheterization lab. We report a case in which three-dimensional magnetic resonance imaging (3D MRI) overlay onto live fluoroscopic imaging was utilized to safely obtain transhepatic access in a 12-year-old patient with prune belly syndrome, complex and distorted abdominal anatomy, and a vascular mass within the liver.

  4. Multivariate clinical models and quantitative dipyridamole-thallium imaging to predict cardiac morbidity and death after vascular reconstruction

    SciTech Connect

    Lette, J.; Waters, D.; Lassonde, J.; Rene, P.; Picard, M.; Laurendeau, F.; Levy, R.; Cerino, M.; Nattel, S. )

    1991-08-01

    Patients with peripheral vascular disease have a high prevalence of coronary artery disease and are at increased risk for cardiac morbidity and death after vascular reconstruction. The present study was undertaken to assess the value of 18 clinical parameters, of 7 clinical scoring systems, and of quantitative dipyridamole-thallium imaging for predicting the occurrence of postoperative myocardial infarction or cardiac death. Vascular surgery was performed in 125 patients. Thirteen postoperative cardiac events occurred, including 10 cardiac deaths and 3 nonfatal infarctions. Clinical parameters were not useful in predicting postoperative outcome. All 63 patients with normal scan results or fixed perfusion defects underwent surgery uneventfully, whereas 21% (13/62) of patients with reversible defects had a postoperative cardiac complication. By use of quantitative scintigraphic indexes we found that patients with reversible defects could be stratified into intermediate and high-risk subgroups with postoperative event rates of 5% (2/47) and 85% (11/13), respectively, despite intensive postoperative monitoring and antianginal medication. Thus in patients unable to complete a standard exercise stress test, postoperative outcome cannot be predicted clinically, whereas dipyridamole-thallium imaging successfully identified all patients who had a postoperative cardiac event. By use of quantification we found that patients with reversible defects can be stratified into an intermediate risk subgroup that can undergo surgery with minimal complication rate and a high-risk subgroup that requires coronary angiography.

  5. A Motion and Flow Insensitive Adiabatic T2-Preparation Module for Cardiac MR Imaging at 3 Tesla

    PubMed Central

    Jenista, Elizabeth R.; Rehwald, Wolfgang G.; Chen, Enn-Ling; Kim, Han W.; Klem, Igor; Parker, Michele A.; Kim, Raymond J.

    2014-01-01

    A versatile method for generating T2-weighting is a T2-preparation (T2-prep) module, which has been used successfully for cardiac imaging at 1.5T. Although it has been applied at 3T, higher fields (B0 ≥ 3T) can degrade B0 and B1 homogeneity and result in non-uniform magnetization preparation. For cardiac imaging, blood flow and cardiac motion may further impair magnetization preparation. In this study, a novel T2-prep module containing multiple adiabatic B1-insensitive refocusing (BIREF-1) pulses is introduced and compared with three previously described modules (a: composite MLEV4, b: modified BIR-4 (mBIR-4), and c: Silver-Hoult–pair). In the static phantom, the proposed module provided similar or better B0 and B1 insensitivity than the other modules. In human subjects (n=21), quantitative measurement of image signal coefficient of variation (CV), reflecting overall image inhomogeneity, was lower for the proposed module (0.10) than for MLEV4 (0.15, p<0.0001), mBIR-4 (0.27, p<0.0001), and Silver-Hoult–pair (0.14, p=0.001) modules. Similarly, qualitative analysis revealed that the proposed module had the best image quality scores and ranking (both, p<0.0001). In conclusion, we present a new T2-preparation module, which is shown to be robust for cardiac imaging at 3T in comparison with existing methods. PMID:23213005

  6. Motion estimation in cardiac fluorescence imaging with scale-space landmarks and optical flow: a comparative study.

    PubMed

    Rodriguez, M P; Nygren, A

    2015-02-01

    Motion artifacts are a major disadvantage of cardiac optical mapping studies. Pixel misalignment due to contraction is a main cause of the presence of gross motion artifacts in action potential recordings. This study is focused on methods for identifying landmarks and tracking the motion of cardiac tissue for preparations in optical mapping recordings. This is a first step toward our long-term goal to implement a landmark-based image registration technique to correct for pixel misalignment in cardiac optical mapping fluorescence videos and, hence, for gross motion artifacts. Preliminary results for the registration step are presented as an initial proof of concept. The characteristics of the optical mapping images are challenging, since their lack of contrast and well-defined features impose a limitation on the techniques than can be used for landmark selection and motion tracking. This paper compares results of motion estimation of the cardiac surface with two approaches that do not rely on high-contrast features: 1) Scale-invariant feature transform (SIFT) detected "keypoints," to be used as landmarks for motion tracking, as well as 2) a classical global optical flow (OF) algorithm. Both are applied to low-contrast and low-resolution cardiac fluorescence images. We demonstrate that the performance of SIFT is superior to that of OF for pixel motion tracking in cardiac optical mapping images with simulated motion. Results for action potential recovery and action potential duration calculation after landmark-based image registration show that SIFT landmark-based registration yields superior performance in this regard as well.

  7. Image reconstruction in higher dimensions: myocardial perfusion imaging of tracer dynamics with cardiac motion due to deformation and respiration

    NASA Astrophysics Data System (ADS)

    Shrestha, Uttam M.; Seo, Youngho; Botvinick, Elias H.; Gullberg, Grant T.

    2015-11-01

    Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variation of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. These results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases slightly due to redistribution of the counts over the cardiac-respiratory gates. Additionally, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images.

  8. Image Reconstruction in Higher Dimensions: Myocardial Perfusion Imaging of Tracer Dynamics with Cardiac Motion Due to Deformation and Respiration

    PubMed Central

    Shrestha, Uttam M.; Seo, Youngho; Botvinick, Elias H.; Gullberg, Grant T.

    2015-01-01

    Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variation of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. These results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases due to redistribution of the counts over the cardiac-respiratory gates. However, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images. PMID:26450115

  9. Image reconstruction in higher dimensions: myocardial perfusion imaging of tracer dynamics with cardiac motion due to deformation and respiration

    DOE PAGES

    Shrestha, Uttam M.; Seo, Youngho; Botvinick, Elias H.; Gullberg, Grant T.

    2015-10-09

    Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variationmore » of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. We find these results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases slightly due to redistribution of the counts over the cardiac-respiratory gates. Additionally, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images.« less

  10. Image reconstruction in higher dimensions: myocardial perfusion imaging of tracer dynamics with cardiac motion due to deformation and respiration

    SciTech Connect

    Shrestha, Uttam M.; Seo, Youngho; Botvinick, Elias H.; Gullberg, Grant T.

    2015-10-09

    Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variation of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. We find these results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases slightly due to redistribution of the counts over the cardiac-respiratory gates. Additionally, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images.

  11. Image reconstruction in higher dimensions: myocardial perfusion imaging of tracer dynamics with cardiac motion due to deformation and respiration.

    PubMed

    Shrestha, Uttam M; Seo, Youngho; Botvinick, Elias H; Gullberg, Grant T

    2015-11-01

    Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variation of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. These results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases slightly due to redistribution of the counts over the cardiac-respiratory gates. Additionally, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images. PMID:26450115

  12. Engineered hybrid cardiac patches with multifunctional electronics for online monitoring and regulation of tissue function.

    PubMed

    Feiner, Ron; Engel, Leeya; Fleischer, Sharon; Malki, Maayan; Gal, Idan; Shapira, Assaf; Shacham-Diamand, Yosi; Dvir, Tal

    2016-06-01

    In cardiac tissue engineering approaches to treat myocardial infarction, cardiac cells are seeded within three-dimensional porous scaffolds to create functional cardiac patches. However, current cardiac patches do not allow for online monitoring and reporting of engineered-tissue performance, and do not interfere to deliver signals for patch activation or to enable its integration with the host. Here, we report an engineered cardiac patch that integrates cardiac cells with flexible, freestanding electronics and a 3D nanocomposite scaffold. The patch exhibited robust electronic properties, enabling the recording of cellular electrical activities and the on-demand provision of electrical stimulation for synchronizing cell contraction. We also show that electroactive polymers containing biological factors can be deposited on designated electrodes to release drugs in the patch microenvironment on demand. We expect that the integration of complex electronics within cardiac patches will eventually provide therapeutic control and regulation of cardiac function.

  13. Subject-specific patch-based denoising for contrast-enhanced cardiac MR images

    NASA Astrophysics Data System (ADS)

    Ma, Lorraine; Ebrahimi, Mehran; Pop, Mihaela

    2016-03-01

    Many patch-based techniques in imaging, e.g., Non-local means denoising, require tuning parameters to yield optimal results. In real-world applications, e.g., denoising of MR images, ground truth is not generally available and the process of choosing an appropriate set of parameters is a challenge. Recently, Zhu et al. proposed a method to define an image quality measure, called Q, that does not require ground truth. In this manuscript, we evaluate the effect of various parameters of the NL-means denoising on this quality metric Q. Our experiments are based on the late-gadolinium enhancement (LGE) cardiac MR images that are inherently noisy. Our described exhaustive evaluation approach can be used in tuning parameters of patch-based schemes. Even in the case that an estimation of optimal parameters is provided using another existing approach, our described method can be used as a secondary validation step. Our preliminary results suggest that denoising parameters should be case-specific rather than generic.

  14. The effects of gantry tilt on breast dose and image noise in cardiac CT

    SciTech Connect

    Hoppe, Michael E.; Gandhi, Diksha; Schmidt, Taly Gilat; Stevens, Grant M.; Foley, W. Dennis

    2013-12-15

    Purpose: This study investigated the effects of tilted-gantry acquisition on image noise and glandular breast dose in females during cardiac computed tomography (CT) scans. Reducing the dose to glandular breast tissue is important due to its high radiosensitivity and limited diagnostic significance in cardiac CT scans.Methods: Tilted-gantry acquisition was investigated through computer simulations and experimental measurements. Upon IRB approval, eight voxelized phantoms were constructed from previously acquired cardiac CT datasets. Monte Carlo simulations quantified the dose deposited in glandular breast tissue over a range of tilt angles. The effects of tilted-gantry acquisition on breast dose were measured on a clinical CT scanner (CT750HD, GE Healthcare) using an anthropomorphic phantom with MOSFET dosimeters in the breast regions. In both simulations and experiments, scans were performed at gantry tilt angles of 0°–30°, in 5° increments. The percent change in breast dose was calculated relative to the nontilted scan for all tilt angles. The percent change in noise standard deviation due to gantry tilt was calculated in all reconstructed simulated and experimental images.Results: Tilting the gantry reduced the breast dose in all simulated and experimental phantoms, with generally greater dose reduction at increased gantry tilts. For example, at 30° gantry tilt, the dosimeters located in the superior, middle, and inferior breast regions measured dose reductions of 74%, 61%, and 9%, respectively. The simulations estimated 0%–30% total breast dose reduction across the eight phantoms and range of tilt angles. However, tilted-gantry acquisition also increased the noise standard deviation in the simulated phantoms by 2%–50% due to increased pathlength through the iodine-filled heart. The experimental phantom, which did not contain iodine in the blood, demonstrated decreased breast dose and decreased noise at all gantry tilt angles.Conclusions: Tilting the

  15. Cardiac imaging in diagnostic VCT using multi-sector data acquisition and image reconstruction: step-and-shoot scan vs. helical scan

    NASA Astrophysics Data System (ADS)

    Tang, Xiangyang; Hsieh, Jiang; Seamans, John L.; Dong, Fang; Okerlund, Darin

    2008-03-01

    Since the advent of multi-slice CT, helical scan has played an increasingly important role in cardiac imaging. With the availability of diagnostic volumetric CT, step-and-shoot scan has been becoming popular recently. Step-and-shoot scan decouples patient table motion from heart beating, and thus the temporal window for data acquisition and image reconstruction can be optimized, resulting in significantly reduced radiation dose, improved tolerance to heart beat rate variation and inter-cycle cardiac motion inconsistency. Multi-sector data acquisition and image reconstruction have been utilized in helical cardiac imaging to improve temporal resolution, but suffers from the coupling of heart beating and patient table motion. Recognizing the clinical demands, the multi-sector data acquisition scheme for step-and-shoot scan is investigated in this paper. The most outstanding feature of the multi-sector data acquisition combined with the stepand- shoot scan is the decoupling of patient table proceeding from heart beating, which offers the opportunities of employing prospective ECG-gating to improve dose efficiency and fine adjusting cardiac imaging phase to suppress artifacts caused by inter-cycle cardiac motion inconsistency. The improvement in temporal resolution and the resultant suppression of motion artifacts are evaluated via motion phantoms driven by artificial ECG signals. Both theoretical analysis and experimental evaluation show promising results for multi-sector data acquisition scheme to be employed with the step-and-shoot scan. With the ever-increasing gantry rotation speed and detector longitudinal coverage in stateof- the-art VCT scanners, it is expected that the step-and-shoot scan with multi-sector data acquisition scheme would play an increasingly important role in cardiac imaging using diagnostic VCT scanners.

  16. The Cardiac Atlas Project—an imaging database for computational modeling and statistical atlases of the heart

    PubMed Central

    Fonseca, Carissa G.; Backhaus, Michael; Bluemke, David A.; Britten, Randall D.; Chung, Jae Do; Cowan, Brett R.; Dinov, Ivo D.; Finn, J. Paul; Hunter, Peter J.; Kadish, Alan H.; Lee, Daniel C.; Lima, Joao A. C.; Medrano−Gracia, Pau; Shivkumar, Kalyanam; Suinesiaputra, Avan; Tao, Wenchao; Young, Alistair A.

    2011-01-01

    Motivation: Integrative mathematical and statistical models of cardiac anatomy and physiology can play a vital role in understanding cardiac disease phenotype and planning therapeutic strategies. However, the accuracy and predictive power of such models is dependent upon the breadth and depth of noninvasive imaging datasets. The Cardiac Atlas Project (CAP) has established a large-scale database of cardiac imaging examinations and associated clinical data in order to develop a shareable, web-accessible, structural and functional atlas of the normal and pathological heart for clinical, research and educational purposes. A goal of CAP is to facilitate collaborative statistical analysis of regional heart shape and wall motion and characterize cardiac function among and within population groups. Results: Three main open-source software components were developed: (i) a database with web-interface; (ii) a modeling client for 3D + time visualization and parametric description of shape and motion; and (iii) open data formats for semantic characterization of models and annotations. The database was implemented using a three-tier architecture utilizing MySQL, JBoss and Dcm4chee, in compliance with the DICOM standard to provide compatibility with existing clinical networks and devices. Parts of Dcm4chee were extended to access image specific attributes as search parameters. To date, approximately 3000 de-identified cardiac imaging examinations are available in the database. All software components developed by the CAP are open source and are freely available under the Mozilla Public License Version 1.1 (http://www.mozilla.org/MPL/MPL-1.1.txt). Availability: http://www.cardiacatlas.org Contact: a.young@auckland.ac.nz Supplementary information: Supplementary data are available at Bioinformatics online. PMID:21737439

  17. Hybrid magnetic nanostructures (MNS) for magnetic resonance imaging applications.

    PubMed

    De, Mrinmoy; Chou, Stanley S; Joshi, Hrushikesh M; Dravid, Vinayak P

    2011-11-01

    The development of MRI contrast agents has experienced its version of the gilded age over the past decade, thanks largely to the rapid advances in nanotechnology. In addition to progress in single mode contrast agents, which ushered in unprecedented R(1) or R(2) sensitivities, there has also been a boon in the development of agents covering more than one mode of detection. These include T(1)-PET, T(2)-PET T(1)-optical, T(2)-optical, T(1)-T(2) agents and many others. In this review, we describe four areas which we feel have experienced particular growth due to nanotechnology, specifically T(2) magnetic nanostructure development, T(1)/T(2)-optical dual mode agents, and most recently the T(1)-T(2) hybrid imaging systems. In each of these systems, we describe applications including in vitro, in vivo usage and assay development. In all, while the benefits and drawbacks of most MRI contrast agents depend on the application at hand, the recent development in multimodal nanohybrids may curtail the shortcomings of single mode agents in diagnostic and clinical settings by synergistically incorporating functionality. It is hoped that as nanotechnology advances over the next decade, it will produce agents with increased diagnostics and assay relevant capabilities in streamlined packages that can meaningfully improve patient care and prognostics. In this review article, we focus on T(2) materials, its surface functionalization and coupling with optical and/or T(1) agents. PMID:21851844

  18. Hybrid Magnetic Nanostructures (MNS) for Magnetic Resonance Imaging Applications

    PubMed Central

    De, Mrinmoy; Chou, Stanley S.; Joshi, Hrushikesh M.

    2011-01-01

    The development of MRI contrast agents has experienced its version of the gilded age over the past decade, thanks largely to the rapid advances in nanotechnology. In addition to progress in single mode contrast agents, which ushered in unprecedented R1 or R2 sensitivities, there has also been a boon in the development of agents covering more than one mode of detection. These include T1-PET, T2-PET T1-optical, T2-optical, T1–T2 agents and many others. In this review, we describe four areas which we feel have experienced particular growth due to nanotechnology, specifically T2 magnetic nanostructure development, T1/T2-optical dual mode agents, and most recently the T1–T2 hybrid imaging systems. In each of these systems, we describe applications including in vitro, in vivo usage and assay development. In all, while the benefits and drawbacks of most MRI contrast agents depend on the application at hand, the recent development in multimodal nanohybrids may curtail the shortcomings of single mode agents in diagnostic and clinical settings by synergistically incorporating functionality. It is hoped that as nanotechnology advances over the next decade, it will produce agents with increased diagnostics and assay relevant capabilities in streamlined packages that can meaningfully improve patient care and prognostics. In this review article, we focus on T2 materials, its surface functionalization and coupling with optical and/or T1 agents. PMID:21851844

  19. Experimental tests of a hybrid pixellated detector for gamma imaging

    NASA Astrophysics Data System (ADS)

    Gal, O.; Mikulec, B.; Million, M.

    2001-03-01

    In the framework of the MEDIPIX Collaboration, a hybrid pixel detector has been developed primarily for X-ray radiography. This detector consists of a 64×64 pixel photon counting chip (PCC), bump bonded to a 200 μm thick GaAs substrate. The PCC is optimised for energy depositions in the range of a few keV to a few tens of keV. The aim of this study is to evaluate the detector for applications in decommissioning of nuclear power plants where typical sources have energies in range of a few hundred keV. Tests were realised using a 137Cs gamma source (660 keV). At this energy, Monte-Carlo simulations predict that, on average, for more than 60% of primary interactions, there is at least one pixel on which the deposited energy exceeds 100 keV. Simulations also allow modelling of the spatial energy spreading. The comparison of the simulation results with experimental data should indicate if there is a significant contribution of electrical cross-coupling between pixels to the cluster size of the detected hits. The results obtained demonstrate promising perspectives for this kind of detector towards gamma imaging applications.

  20. Noninvasive functional cardiac electrical source imaging: combining MRI and ECG mapping for imaging electrical function

    NASA Astrophysics Data System (ADS)

    Tilg, Bernhard; Modre, Robert; Fischer, Gerald; Hanser, Friedrich; Messnarz, Bernd; Schocke, Michael F. H.; Kremser, Christian; Roithinger, Franz

    2002-04-01

    Inverse electrocardiography has been developing for several years. By coupling electrocardiographic mapping and 3D+time anatomical data, the electrical excitation sequence can be imaged completely noninvasively in the human heart. In this study, a bidomain theory based surface heart model activation time imaging approach was applied to single beat data of atrial and ventricular depolarization. For sinus and paced rhythms, the sites of early activation and the areas with late activation were estimated with sufficient accuracy. In particular for focal arrhythmias, this model-based imaging approach might allow the guidance and evaluation of antiarrhythmic interventions, for instance, in case of catheter ablation or drug therapy.

  1. Precise reconstruction of fast moving cardiac valve in high frame rate synthetic transmit aperture ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Suzuki, Mayumi; Ikeda, Teiichiro; Ishihara, Chizue; Takano, Shinta; Masuzawa, Hiroshi

    2016-04-01

    To diagnose heart valve incompetence, i.e., one of the most serious cardiac dysfunctions, it is essential to obtain images of fast-moving valves at high spatial and temporal resolution. Ultrasound synthetic transmit aperture (STA) imaging has the potential to achieve high spatial resolution by synthesizing multiple pre-beamformed images obtained with corresponding multiple transmissions. However, applying STA to fast-moving targets is difficult due to serious target deformation. We propose a high-frame-rate STA (fast STA) imaging method that uses a reduced number of transmission events needed for each image. Fast STA is expected to suppress deformation of moving targets; however, it may result in deteriorated spatial resolution. In this study, we conducted a simulation study to evaluate fast STA. We quantitatively evaluated the reduction in deformation and deterioration of spatial resolution with a model involving a radially moving valve at the maximum speed of 0.5 m/s. The simulated raw channel data of the valve phantom was processed with offline beamforming programs. We compared B-mode images obtained through single received-line in a transmission (SRT) method, STA, and fast STA. The results show that fast STA with four-times-reduced events is superior in reconstructing the original shape of the moving valve to other methods. The accuracy of valve location is 97 and 100% better than those with SRT and STA, respectively. The resolution deterioration was found to be below the annoyance threshold considering the improved performance of the shape reconstruction. The obtained results are promising for providing more precise diagnostic information on cardiovascular diseases.

  2. Myocardial Extracellular Volume Fraction with Dual-Energy Equilibrium Contrast-enhanced Cardiac CT in Nonischemic Cardiomyopathy: A Prospective Comparison with Cardiac MR Imaging.

    PubMed

    Lee, Hye-Jeong; Im, Dong Jin; Youn, Jong-Chan; Chang, Suyon; Suh, Young Joo; Hong, Yoo Jin; Kim, Young Jin; Hur, Jin; Choi, Byoung Wook

    2016-07-01

    Purpose To evaluate the feasibility of equilibrium contrast material-enhanced dual-energy cardiac computed tomography (CT) to determine extracellular volume fraction (ECV) in nonischemic cardiomyopathy (CMP) compared with magnetic resonance (MR) imaging. Materials and Methods This study was approved by the institutional review board; informed consent was obtained. Seven healthy subjects and 23 patients (six with hypertrophic CMP, nine with dilated CMP, four with amyloidosis, and four with sarcoidosis) (mean age ± standard deviation, 57.33 years ± 14.82; 19 male participants [63.3%]) were prospectively enrolled. Twelve minutes after contrast material injection (1.8 mL/kg at 3 mL/sec), dual-energy cardiac CT was performed. ECV was measured by two observers independently. Hematocrit levels were compared between healthy subjects and patients with the Mann-Whitney U test. In per-subject analysis, interobserver agreement for CT was assessed with the intraclass correlation coefficient (ICC), and intertest agreement between MR imaging and CT was assessed with Bland-Altman analysis. In per-segment analysis, Student t tests in the linear mixed model were used to compare ECV on CT images between healthy subjects and patients. Results Hematocrit level was 43.44% ± 1.80 for healthy subjects and 41.23% ± 5.61 for patients with MR imaging (P = .16) and 43.50% ± 1.92 for healthy subjects and 41.35% ± 5.92 for patients with CT (P = .15). For observer 1 in per-subject analysis, ECV was 34.18% ± 8.98 for MR imaging and 34.48% ± 8.97 for CT. For observer 2, myocardial ECV was 34.42% ± 9.03 for MR imaging and 33.98% ± 9.05 for CT. Interobserver agreement for ECV at CT was excellent (ICC = 0.987). Bland-Altman analysis between MR imaging and CT showed a small bias (-0.06%), with 95% limits of agreement of -1.19 and 1.79. Compared with healthy subjects, patients with hypertrophic CMP, dilated CMP, amyloidosis, and sarcoidosis had significantly higher myocardial ECV at dual

  3. Myocardial Extracellular Volume Fraction with Dual-Energy Equilibrium Contrast-enhanced Cardiac CT in Nonischemic Cardiomyopathy: A Prospective Comparison with Cardiac MR Imaging.

    PubMed

    Lee, Hye-Jeong; Im, Dong Jin; Youn, Jong-Chan; Chang, Suyon; Suh, Young Joo; Hong, Yoo Jin; Kim, Young Jin; Hur, Jin; Choi, Byoung Wook

    2016-07-01

    Purpose To evaluate the feasibility of equilibrium contrast material-enhanced dual-energy cardiac computed tomography (CT) to determine extracellular volume fraction (ECV) in nonischemic cardiomyopathy (CMP) compared with magnetic resonance (MR) imaging. Materials and Methods This study was approved by the institutional review board; informed consent was obtained. Seven healthy subjects and 23 patients (six with hypertrophic CMP, nine with dilated CMP, four with amyloidosis, and four with sarcoidosis) (mean age ± standard deviation, 57.33 years ± 14.82; 19 male participants [63.3%]) were prospectively enrolled. Twelve minutes after contrast material injection (1.8 mL/kg at 3 mL/sec), dual-energy cardiac CT was performed. ECV was measured by two observers independently. Hematocrit levels were compared between healthy subjects and patients with the Mann-Whitney U test. In per-subject analysis, interobserver agreement for CT was assessed with the intraclass correlation coefficient (ICC), and intertest agreement between MR imaging and CT was assessed with Bland-Altman analysis. In per-segment analysis, Student t tests in the linear mixed model were used to compare ECV on CT images between healthy subjects and patients. Results Hematocrit level was 43.44% ± 1.80 for healthy subjects and 41.23% ± 5.61 for patients with MR imaging (P = .16) and 43.50% ± 1.92 for healthy subjects and 41.35% ± 5.92 for patients with CT (P = .15). For observer 1 in per-subject analysis, ECV was 34.18% ± 8.98 for MR imaging and 34.48% ± 8.97 for CT. For observer 2, myocardial ECV was 34.42% ± 9.03 for MR imaging and 33.98% ± 9.05 for CT. Interobserver agreement for ECV at CT was excellent (ICC = 0.987). Bland-Altman analysis between MR imaging and CT showed a small bias (-0.06%), with 95% limits of agreement of -1.19 and 1.79. Compared with healthy subjects, patients with hypertrophic CMP, dilated CMP, amyloidosis, and sarcoidosis had significantly higher myocardial ECV at dual

  4. Thallium-201 perfusion imaging with atrial pacing or dipyridamole stress testing for evaluation of cardiac risk prior to nonvascular surgery

    SciTech Connect

    Stratmann, H.G.; Mark, A.L.; Williams, G.A. )

    1990-09-01

    Preoperative assessment of cardiac risk using thallium-201 scintigraphy and atrial pacing (n = 42) or dipyridamole stress testing (n = 35) was performed in 77 patients (mean age 65 +/- 7 years), who subsequently underwent elective nonvascular surgery. All patients were at low cardiac risk by clinical criteria; none could perform exercise stress testing due to physical limitations. ST depression consistent with ischemia occurred in 11 patients during atrial pacing and in 1 patient during dipyridamole stress testing (p less than 0.01). Nine patients had reversible perfusion defects with atrial pacing, and 10 patients with dipyridamole stress testing; fixed defects were present in 15 and 8 patients, respectively. Only one patient (fixed perfusion defect with atrial pacing, left main disease on coronary angiography) underwent preoperative coronary revascularization. Two patients subsequently had postoperative cardiac events. One patient (reversible perfusion defect with dipyridamole stress testing) experienced sudden death after a nonvascular procedure, while a second patient (normal thallium images with dipyridamole testing) had a nonfatal myocardial infarction. In patients having atrial pacing or dipyridamole stress testing, thallium-201 scans that are normal or show only a fixed perfusion defect confirm a low risk of cardiac complications following nonvascular surgery. The presence of a reversible perfusion defect does not preclude a postoperative course free of cardiac complications in patients at low cardiac risk by clinical criteria.

  5. Three-dimensional representation of integration of functional coronary angiograms and nuclear cardiac imaging

    NASA Astrophysics Data System (ADS)

    Spruijt, Hugo J.; Wahle, Andreas; Marques, Koen M. J.; Westerhof, Nico; Heethaar, Robert M.; Bronzwaer, Jean G.; Visser, Frans C.

    2002-04-01

    The combination of quantitative coronary analysis and flow reserve measurements enables the clinician to determine whether a coronary artery stenosis is significant and therefore has to be treated. 2-D SPECT polar diagrams are made to get information on cardiac perfusion. However, no real 3-D comparison between the anatomical coronary angiography data and the perfusion information can be made. In this feasibility study a first approach is made to create fusion images in 3-D of angiograms and SPECT data. From biplane coronary arteriograms (CAGs), both left and right coronary arteries of five patients have been reconstructed as 3-D models. The reconstruction output was automatically converted into Virtual Reality Markup Language (VRML) scenes. The 2-D polar SPECT data were mapped onto a half-ellipsoid and added to the VRML scene. Registration of the three models was performed interactively using VRML and common Internet browsers.

  6. Ex Vivo 3D Diffusion Tensor Imaging and Quantification of Cardiac Laminar Structure

    PubMed Central

    Helm, Patrick A.; Tseng, Hsiang-Jer; Younes, Laurent; McVeigh, Elliot R.; Winslow, Raimond L.

    2007-01-01

    A three-dimensional (3D) diffusion-weighted imaging (DWI) method for measuring cardiac fiber structure at high spatial resolution is presented. The method was applied to the ex vivo reconstruction of the fiber architecture of seven canine hearts. A novel hypothesis-testing method was developed and used to show that distinct populations of secondary and tertiary eigenvalues may be distinguished at reasonable confidence levels (P ≤ 0.01) within the canine ventricle. Fiber inclination and sheet angles are reported as a function of transmural depth through the anterior, lateral, and posterior left ventricle (LV) free wall. Within anisotropic regions, two consistent and dominant orientations were identified, supporting published results from histological studies and providing strong evidence that the tertiary eigenvector of the diffusion tensor (DT) defines the sheet normal. PMID:16149057

  7. Ex vivo 3D diffusion tensor imaging and quantification of cardiac laminar structure.

    PubMed

    Helm, Patrick A; Tseng, Hsiang-Jer; Younes, Laurent; McVeigh, Elliot R; Winslow, Raimond L

    2005-10-01

    A three-dimensional (3D) diffusion-weighted imaging (DWI) method for measuring cardiac fiber structure at high spatial resolution is presented. The method was applied to the ex vivo reconstruction of the fiber architecture of seven canine hearts. A novel hypothesis-testing method was developed and used to show that distinct populations of secondary and tertiary eigenvalues may be distinguished at reasonable confidence levels (P < or = 0.01) within the canine ventricle. Fiber inclination and sheet angles are reported as a function of transmural depth through the anterior, lateral, and posterior left ventricle (LV) free wall. Within anisotropic regions, two consistent and dominant orientations were identified, supporting published results from histological studies and providing strong evidence that the tertiary eigenvector of the diffusion tensor (DT) defines the sheet normal.

  8. RF interference suppression in a cardiac synchronization system operating in a high magnetic field NMR imaging system

    SciTech Connect

    Damji, A.A.; Snyder, R.E.; Ellinger, D.C.; Witkowski, F.X.; Allen, P.S.

    1988-11-01

    An electrocardiographic (ECG) unit suitable for cardiac-synchronized nuclear magnetic resonance imaging in high magnetic fields is presented. The unit includes lossy transmission lines as ECG leads in order to suppress radio frequency (RF) interference in the electrocardiogram. The unit's immunity to RF interference is demonstrated.

  9. Improved cardiac motion detection from ultrasound images using TDIOF: a combined B-mode/ tissue Doppler approach

    NASA Astrophysics Data System (ADS)

    Tavakoli, Vahid; Stoddard, Marcus F.; Amini, Amir A.

    2013-03-01

    Quantitative motion analysis of echocardiographic images helps clinicians with the diagnosis and therapy of patients suffering from cardiac disease. Quantitative analysis is usually based on TDI (Tissue Doppler Imaging) or speckle tracking. These methods are based on two independent techniques - the Doppler Effect and image registration, respectively. In order to increase the accuracy of the speckle tracking technique and cope with the angle dependency of TDI, herein, a combined approach dubbed TDIOF (Tissue Doppler Imaging Optical Flow) is proposed. TDIOF is formulated based on the combination of B-mode and Doppler energy terms in an optical flow framework and minimized using algebraic equations. In this paper, we report on validations with simulated, physical cardiac phantom, and in-vivo patient data. It is shown that the additional Doppler term is able to increase the accuracy of speckle tracking, the basis for several commercially available echocardiography analysis techniques.

  10. Multi-oriented windowed harmonic phase reconstruction for robust cardiac strain imaging.

    PubMed

    Cordero-Grande, Lucilio; Royuela-del-Val, Javier; Sanz-Estébanez, Santiago; Martín-Fernández, Marcos; Alberola-López, Carlos

    2016-04-01

    The purpose of this paper is to develop a method for direct estimation of the cardiac strain tensor by extending the harmonic phase reconstruction on tagged magnetic resonance images to obtain more precise and robust measurements. The extension relies on the reconstruction of the local phase of the image by means of the windowed Fourier transform and the acquisition of an overdetermined set of stripe orientations in order to avoid the phase interferences from structures outside the myocardium and the instabilities arising from the application of a gradient operator. Results have shown that increasing the number of acquired orientations provides a significant improvement in the reproducibility of the strain measurements and that the acquisition of an extended set of orientations also improves the reproducibility when compared with acquiring repeated samples from a smaller set of orientations. Additionally, biases in local phase estimation when using the original harmonic phase formulation are greatly diminished by the one here proposed. The ideas here presented allow the design of new methods for motion sensitive magnetic resonance imaging, which could simultaneously improve the resolution, robustness and accuracy of motion estimates.

  11. Fluoroscopy-based method to determine heart geometry for functional imaging of cardiac electrical activity

    NASA Astrophysics Data System (ADS)

    Ghanem, Raja N.; Ramanathan, Charulatha; Jia, Ping; Rudy, Yoram

    2003-05-01

    A fluoroscopy based method for determining heart surface geometry has been developed and validated in phantom and human studies. Biplane fluoroscopic projections were calibrated independently. The heart contour was segmented in each projection and corresponding contour points were matched using epipolar geometry. Points in 3D were reconstructed from the corresponding contour points using point reconstruction. B-splines were approximated from the reconstructed points and meshed to form the heart surface. The fluoroscopy-reconstructed heart was validated in a phantom and human study by comparison to CT imaging. Mean, minimum, maximum and standard deviation of the absolute distance errors were computed for the fluoroscopy-reconstructed heart relative to the CT heart. The mean absolute distance error for the phantom was 4mm. The mean absolute distance error for the human subject was 10 mm. In addition to validating the geometry, we also evaluated in the human subject the feasibility of noninvasive imaging of normal cardiac electrical activity on the fluoroscopy-reconstructed heart by comparing the results to those obtained on the CT heart. Noninvasive images on the fluoroscopy-reconstructed heart by showed close correlation with those obtained on the CT heart (CC=0.70).

  12. Accuracy and Robustness Improvements of Echocardiographic Particle Image Velocimetry for Routine Clinical Cardiac Evaluation

    NASA Astrophysics Data System (ADS)

    Meyers, Brett; Vlachos, Pavlos; Charonko, John; Giarra, Matthew; Goergen, Craig

    2015-11-01

    Echo Particle Image Velocimetry (echoPIV) is a recent development in flow visualization that provides improved spatial resolution with high temporal resolution in cardiac flow measurement. Despite increased interest a limited number of published echoPIV studies are clinical, demonstrating that the method is not broadly accepted within the medical community. This is due to the fact that use of contrast agents are typically reserved for subjects whose initial evaluation produced very low quality recordings. Thus high background noise and low contrast levels characterize most scans, which hinders echoPIV from producing accurate measurements. To achieve clinical acceptance it is necessary to develop processing strategies that improve accuracy and robustness. We hypothesize that using a short-time moving window ensemble (MWE) correlation can improve echoPIV flow measurements on low image quality clinical scans. To explore the potential of the short-time MWE correlation, evaluation of artificial ultrasound images was performed. Subsequently, a clinical cohort of patients with diastolic dysfunction was evaluated. Qualitative and quantitative comparisons between echoPIV measurements and Color M-mode scans were carried out to assess the improvements delivered by the proposed methodology.

  13. Multi-oriented windowed harmonic phase reconstruction for robust cardiac strain imaging.

    PubMed

    Cordero-Grande, Lucilio; Royuela-del-Val, Javier; Sanz-Estébanez, Santiago; Martín-Fernández, Marcos; Alberola-López, Carlos

    2016-04-01

    The purpose of this paper is to develop a method for direct estimation of the cardiac strain tensor by extending the harmonic phase reconstruction on tagged magnetic resonance images to obtain more precise and robust measurements. The extension relies on the reconstruction of the local phase of the image by means of the windowed Fourier transform and the acquisition of an overdetermined set of stripe orientations in order to avoid the phase interferences from structures outside the myocardium and the instabilities arising from the application of a gradient operator. Results have shown that increasing the number of acquired orientations provides a significant improvement in the reproducibility of the strain measurements and that the acquisition of an extended set of orientations also improves the reproducibility when compared with acquiring repeated samples from a smaller set of orientations. Additionally, biases in local phase estimation when using the original harmonic phase formulation are greatly diminished by the one here proposed. The ideas here presented allow the design of new methods for motion sensitive magnetic resonance imaging, which could simultaneously improve the resolution, robustness and accuracy of motion estimates. PMID:26745763

  14. Cardiac function and perfusion dynamics measured on a beat-by-beat basis in the live mouse using ultra-fast 4D optoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Ford, Steven J.; Deán-Ben, Xosé L.; Razansky, Daniel

    2015-03-01

    The fast heart rate (~7 Hz) of the mouse makes cardiac imaging and functional analysis difficult when studying mouse models of cardiovascular disease, and cannot be done truly in real-time and 3D using established imaging modalities. Optoacoustic imaging, on the other hand, provides ultra-fast imaging at up to 50 volumetric frames per second, allowing for acquisition of several frames per mouse cardiac cycle. In this study, we combined a recently-developed 3D optoacoustic imaging array with novel analytical techniques to assess cardiac function and perfusion dynamics of the mouse heart at high, 4D spatiotemporal resolution. In brief, the heart of an anesthetized mouse was imaged over a series of multiple volumetric frames. In another experiment, an intravenous bolus of indocyanine green (ICG) was injected and its distribution was subsequently imaged in the heart. Unique temporal features of the cardiac cycle and ICG distribution profiles were used to segment the heart from background and to assess cardiac function. The 3D nature of the experimental data allowed for determination of cardiac volumes at ~7-8 frames per mouse cardiac cycle, providing important cardiac function parameters (e.g., stroke volume, ejection fraction) on a beat-by-beat basis, which has been previously unachieved by any other cardiac imaging modality. Furthermore, ICG distribution dynamics allowed for the determination of pulmonary transit time and thus additional quantitative measures of cardiovascular function. This work demonstrates the potential for optoacoustic cardiac imaging and is expected to have a major contribution toward future preclinical studies of animal models of cardiovascular health and disease.

  15. Hybrid Nanotrimers for Dual T1 and T2-Weighted Magnetic Resonance Imaging

    PubMed Central

    2015-01-01

    Development of multifunctional nanoparticle-based probes for dual T1- and T2-weighted magnetic resonance imaging (MRI) could allow us to image and diagnose the tumors or other abnormalities in an exceptionally accurate and reliable manner. In this study, by fusing distinct nanocrystals via solid-state interfaces, we built hybrid heteronanostructures to combine both T1 and T2- weighted contrast agents together for MRI with high accuracy and reliability. The resultant hybrid heterotrimers showed high stability in physiological conditions and could induce both simultaneous positive and negative contrast enhancements in MR images. Small animal positron emission tomography imaging study revealed that the hybrid heterostructures displayed favorable biodistribution and were suitable for in vivo imaging. Their potential as dual contrast agents for T1 and T2-weighted MRI was further demonstrated by in vitro and in vivo imaging and relaxivity measurements. PMID:25283972

  16. Cardiac catheterization

    MedlinePlus

    Catheterization - cardiac; Heart catheterization; Angina - cardiac catheterization; CAD - cardiac catheterization; Coronary artery disease - cardiac catheterization; Heart valve - cardiac catheterization; Heart failure - ...

  17. Automated classification of LV regional wall motion based on spatio-temporal profiles from cardiac cine magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Mantilla, Juan; Garreau, Mireille; Bellanger, Jean-Jacques; Paredes, José Luis

    2013-11-01

    Assessment of the cardiac Left Ventricle (LV) wall motion is generally based on visual inspection or quantitative analysis of 2D+t sequences acquired in short-axis cardiac cine-Magnetic Resonance Imaging (MRI). Most often, cardiac dynamic is globally analized from two particular phases of the cardiac cycle. In this paper, we propose an automated method to classify regional wall motion in LV function based on spatio-temporal pro les and Support Vector Machines (SVM). This approach allows to obtain a binary classi cation between normal and abnormal motion, without the need of pre-processing and by exploiting all the images of the cardiac cycle. In each short- axis MRI slice level (basal, median, and apical), the spatio-temporal pro les are extracted from the selection of a subset of diametrical lines crossing opposites LV segments. Initialized at end-diastole phase, the pro les are concatenated with their corresponding projections into the succesive temporal phases of the cardiac cycle. These pro les are associated to di erent types of information that derive from the image (gray levels), Fourier, Wavelet or Curvelet domains. The approach has been tested on a set of 14 abnormal and 6 healthy patients by using a leave-one-out cross validation and two kernel functions for SVM classi er. The best classi cation performance is yielded by using four-level db4 wavelet transform and SVM with a linear kernel. At each slice level the results provided a classi cation rate of 87.14% in apical level, 95.48% in median level and 93.65% in basal level.

  18. Hybrid model for analysis of abnormalities in diabetic cardiomyopathy and diabetic retinopathy related images.

    PubMed

    Shaik, Fahimuddin; Sharma, Anil Kumar; Ahmed, Syed Musthak

    2016-01-01

    At present image processing methods hold a noteworthy position in unravelling various medical imaging challenges. The high risk disorders such as diabetic cardiomyopathy and diabetic retinopathy are considered as applications for proposed method. The dictum of this paper is on observing enhancement and segmentation of the cross sectional view of a blood capillary of a right coronary artery image of a diabetic patient and also retinal images. A hybrid model using hybrid morphological reconstruction technique as pre-processing with watershed segmentation method as post-processing is developed in this work. PMID:27186471

  19. Alternative hybrid and staged interventional treatment of congenital heart defects in critically ill children with complex and non-cardiac problems

    PubMed Central

    Chojnicki, Maciej; Jaworski, Radosław; Steffens, Mariusz; Szofer-Sendrowska, Aneta; Paczkowski, Konrad; Kwaśniak, Ewelina; Zieliński, Jacek; Gierat-Haponiuk, Katarzyna; Leszczyńska, Katarzyna

    2015-01-01

    Introduction An individually designed strategy of comprehensive alternative hybrid and staged interventional treatment (AHASIT) can be a reasonable alternative to conventional treatment of congenital heart defects, reduce the risk of cardiac surgery or interventions performed separately, and give an additional chance for critically ill children. Aim To present our experience and the results of AHASIT of severely ill or borderline children referred for surgery with the diagnosis of congenital heart defects. Material and methods A group of 22 patients with complex cardiac and non-cardiac pathologies was retrospectively selected and analyzed. An individual preoperative severity scale was established for AHASIT patients, with one point for each of the following preoperative complications: prematurity, low body weight, cyanosis, intolerance to drug therapy, failed interventional treatment prior to admission, mechanical ventilation prior to the procedure, chronic respiratory failure and non-cardiac, mainly congenital malformations (congenital diaphragmatic hernia, lower extremity agenesia, duodenal atresia) and acquired problems (newborn edema, necrotic enterocolitis, intracranial hemorrhage, liver and renal failure, anemia and thrombocytopenia, infections or colonization with drug-resistant pathogens). Results The analysis of the postoperative course showed that the patients with 5 AHASIT points or more had a more complicated postoperative course than the patients with 1 to 4 AHASIT points. Conclusions The AHASIT of pediatric congenital heart defects with complex and non-cardiac problems appeared to be an attractive option for selected severely ill patients. The strategy was found to be effective in selected neonates suffering from complex and accompanying non-cardiac pathologies, with positive final results of both cardiological intervention and planned surgery. PMID:26240625

  20. Assessment of cardiac function using myocardial perfusion imaging technique on SPECT with 99mTc sestamibi

    NASA Astrophysics Data System (ADS)

    Gani, M. R. A.; Nazir, F.; Pawiro, S. A.; Soejoko, D. S.

    2016-03-01

    Suspicion on coronary heart disease can be confirmed by observing the function of left ventricle cardiac muscle with Myocardial Perfusion Imaging techniques. The function perfusion itself is indicated by the uptake of radiopharmaceutical tracer. The 31 patients were studied undergoing the MPI examination on Gatot Soebroto Hospital using 99mTc-sestamibi radiopharmaceutical with stress and rest conditions. Stress was stimulated by physical exercise or pharmacological agent. After two hours, the patient did rest condition on the same day. The difference of uptake percentage between stress and rest conditions will be used to determine the malfunction of perfusion due to ischemic or infarct. Degradation of cardiac function was determined based on the image-based assessment of five segments of left ventricle cardiac. As a result, 8 (25.8%) patients had normal myocardial perfusion and 11 (35.5%) patients suspected for having partial ischemia. Total ischemia occurred to 8 (25.8%) patients with reversible and irreversible ischemia and the remaining 4 (12.9%) patients for partial infarct with characteristic the percentage of perfusion ≤50%. It is concluded that MPI technique of image-based assessment on uptake percentage difference between stress and rest conditions can be employed to predict abnormal perfusion as complementary information to diagnose the cardiac function.

  1. Utility of cardiac magnetic resonance imaging, echocardiography and electrocardiography for the prediction of clinical response and long-term survival following cardiac resynchronisation therapy.

    PubMed

    Ellims, Andris H; Pfluger, Heinz; Elsik, Maros; Butler, Michelle J; Hare, James L; Taylor, Andrew J

    2013-08-01

    Cardiac resynchronisation therapy (CRT) can reduce symptoms, hospitalisations, and mortality in patients with severe left ventricular (LV) systolic dysfunction and electro-mechanical dyssynchrony. Unfortunately, approximately 30 % of eligible patients fail to respond to CRT. This study prospectively compared electrocardiography (ECG), echocardiography, and cardiac magnetic resonance (CMR) imaging for the prediction of response to CRT. We performed ECG, echocardiography and CMR on 46 patients prior to planned CRT implantation. Patients were divided into predicted responder and non-responder groups using previously described criteria for each modality. Changes in indicators of CRT response were recorded 6 months post-implantation, and later for transplant-free survival. Less dyspnoea, lower levels of N-terminal pro-brain natriuretic peptide, more LV reverse remodelling, and longer transplant-free survival were observed in predicted responders compared to predicted non-responders using each of the three modalities (p < 0.05 for each comparison). Additionally, for patients with QRS duration <150 ms and/or non-left bundle branch block (non-LBBB) QRS morphology, CMR predicted both clinical response and improved longer term transplant-free survival (80 % transplant-free survival in predicted responders vs. 20 % in predicted non-responders, p = 0.04). ECG and cardiac imaging techniques predict improvements in markers of response following CRT with similar accuracy. However, for CRT candidates with shorter, non-LBBB QRS complexes, a subgroup known to derive less benefit from CRT, CMR may predict those who are more likely to gain both symptomatic and survival benefits.

  2. Assessment of Left Ventricular Function in Cardiac MSCT Imaging by a 4D Hierarchical Surface-Volume Matching Process

    PubMed Central

    Simon, Antoine; Boulmier, Dominique; Coatrieux, Jean-Louis; Le Breton, Hervé

    2006-01-01

    Multislice computed tomography (MSCT) scanners offer new perspectives for cardiac kinetics evaluation with 4D dynamic sequences of high contrast and spatiotemporal resolutions. A new method is proposed for cardiac motion extraction in multislice CT. Based on a 4D hierarchical surface-volume matching process, it provides the detection of the heart left cavities along the acquired sequence and the estimation of their 3D surface velocity fields. A Markov random field model is defined to find, according to topological descriptors, the best correspondences between a 3D mesh describing the left endocardium at one time and the 3D acquired volume at the following time. The global optimization of the correspondences is realized with a multiresolution process. Results obtained on simulated and real data show the capabilities to extract clinically relevant global and local motion parameters and highlight new perspectives in cardiac computed tomography imaging. PMID:23165027

  3. Evaluation of a robotic arm for echocardiography to X-ray image registration during cardiac catheterization procedures.

    PubMed

    Ma, Yingliang; Penney, Graeme P; Bos, Dennis; Frissen, Peter; de Fockert, George; King, Andy; Gao, Gang; Yao, Cheng; Totman, John; Ginks, Matthew; Rinaldi, C; Razavi, Reza; Rhode, Kawal S

    2009-01-01

    We present an initial evaluation of a robotic arm for positioning a 3D echo probe during cardiac catheterization procedures. By tracking the robotic arm, X-ray table and X-ray C-arm, we are able to register the 3D echo images with live 2D X-ray images. In addition, we can also use tracking data from the robotic arm combined with system calibrations to create extended field of view 3D echo images. Both these features can be used for roadmapping to guide cardiac catheterization procedures. We have carried out a validation experiment of our registration method using a cross-wire phantom. Results show our method to be accurate to 3.5 mm. We have successfully demonstrated the creation of the extended field of view data on 2 healthy volunteers and the registration of echo and X-ray data on 1 patient undergoing a pacing study. PMID:19964867

  4. Investigations on the efficiency of cardiac-gated methods for the acquisition of diffusion-weighted images

    NASA Astrophysics Data System (ADS)

    Nunes, Rita G.; Jezzard, Peter; Clare, Stuart

    2005-11-01

    Diffusion-weighted images are inherently very sensitive to motion. Pulsatile motion of the brain can give rise to artifactual signal attenuation leading to over-estimation of the apparent diffusion coefficients, even with snapshot echo planar imaging. Such miscalculations can result in erroneous estimates of the principal diffusion directions. Cardiac gating can be performed to confine acquisition to the quiet portion of the cycle. Although effective, this approach leads to significantly longer acquisition times. On the other hand, it has been demonstrated that pulsatile motion is not significant in regions above the corpus callosum. To reduce acquisition times and improve the efficiency of whole brain cardiac-gated acquisitions, the upper slices of the brain can be imaged during systole, reserving diastole for those slices most affected by pulsatile motion. The merits and disadvantages of this optimized approach are investigated here, in comparison to a more standard gating method and to the non-gated approach.

  5. CMR Imaging With Rapid Visual T1 Assessment Predicts Mortality in Patients Suspected of Cardiac Amyloidosis

    PubMed Central

    White, James A.; Kim, Han W.; Shah, Dipan; Fine, Nowell; Kim, Ki-Young; Wendell, David C.; Al-Jaroudi, Wael; Parker, Michele; Patel, Manesh; Gwadry-Sridhar, Femida; Judd, Robert M.; Kim, Raymond J.

    2014-01-01

    OBJECTIVES This study tested the diagnostic and prognostic utility of a rapid, visual T1 assessment method for identification of cardiac amyloidosis (CA) in a “real-life” referral population undergoing cardiac magnetic resonance for suspected CA. BACKGROUND In patients with confirmed CA, delayed-enhancement cardiac magnetic resonance (DE-CMR) frequently shows a diffuse, global hyperenhancement (HE) pattern. However, imaging is often technically challenging, and the prognostic significance of diffuse HE is unclear. METHODS Ninety consecutive patients referred for suspected CA and 64 hypertensive patients with left ventricular hypertrophy (LVH) were prospectively enrolled and underwent a modified DE-CMR protocol. After gadolinium administration a method for rapid, visual T1 assessment was used to identify the presence of diffuse HE during the scan, allowing immediate optimization of settings for the conventional DE-CMR that followed. The primary endpoint was all-cause mortality. RESULTS Among patients with suspected CA, 66% (59 of 90) demonstrated HE, with 81% (48 of 59) of these meeting pre-specified visual T1 assessment criteria for diffuse HE. Among hypertensive LVH patients, 6% (4 of 64) had HE, with none having diffuse HE. During 29 months of follow-up (interquartile range: 12 to 44 months), there were 50 (56%) deaths in patients with suspected CA and 4 (6%) in patients with hypertensive LVH. Multivariable analysis demonstrated that the presence of diffuse HE was the most important predictor of death in the group with suspected CA (hazard ratio: 5.5, 95% confidence interval: 2.7 to 11.0; p < 0.0001) and in the population as a whole (hazard ratio: 6.0, 95% confidence interval 3.0 to 12.1; p < 0.0001). Among 25 patients with myocardial histology obtained during follow-up, the sensitivity, specificity, and accuracy of diffuse HE in the diagnosis of CA were 93%, 70%, and 84%, respectively. CONCLUSIONS Among patients suspected of CA, the presence of diffuse HE by

  6. Evaluation of cardiac functions of cirrhotic children using serum brain natriuretic peptide and tissue Doppler imaging

    PubMed Central

    Fattouh, Aya M; El-Shabrawi, Mortada H; Mahmoud, Enas H; Ahmed, Wafaa O

    2016-01-01

    Background: Cirrhotic cardiomyopathy (CCM) is described as the presence of cardiac dysfunction in cirrhotic patients. In children with chronic liver disease, CCM has been very rarely investigated. The Aim of the Study: Is to evaluate the cardiac function of cirrhotic children to identify those with CCM. Patients and Methods: Fifty-two cirrhotic patients and 53 age and sex matched controls were assessed using serum brain-type natriuretic peptide (BNP), conventional echocardiography, and tissue Doppler imaging. Results: Patients’ mean ages were 7.66 ± 4.16 years (vs. 6.88 ± 3.04 years for the controls). The study included 27 males and 25 females (28 and 25 respectively for the controls). Patients had larger left atrium and right ventricle (RV) (P value 0.05) and increased LV posterior wall thickness than controls (P value 0.04). They had higher late atrial diastolic filling velocity (A) of tricuspid valve (TV) inflow (0.59 ± 0.17 vs. 0.5 ± 0.1 m/s, P < 0.001) and lower ratios between the early diastolic filling velocity (E) and A wave velocity (E/A) of both mitral valve and TV inflow (1.7 ± 0.35 vs. 1.87 ± 0.34 and 1.3 ± 0.3 vs. 1.5 ± 0.3, P < 0.005 and 0.0008, respectively). Patients had significantly longer isovolumic relaxation time of LV (45.5 ± 11.1 vs. 40.5 ± 7.7 ms P 0.008), higher late diastolic peak myocardial velocity (A’) (11.8 ± 3.6 vs. 9.5 ± 2.7 ms, P 0.0003) and systolic velocity (S’) of the RV (14.5 ± 2.7 vs. 13.2 ± 2.9, P 0.01) and significantly higher myocardial performance index of both LV and RV (P 0.001 and 0.01). BNP levels were significantly higher in cases than controls (5.25 ng/l vs. 3.75 ng/l, P < 0.04) and was correlated with the E wave velocity of the TV (r 0.004) and the E/E’ ratio of the RV (r 0.001). None of the clinical or laboratory data were correlated with the BNP level. Conclusion Cirrhotic children have cardiac dysfunction mainly in the form of diastolic dysfunction. There is a need that CCM be more accurately

  7. Fluorescent magnetic iron oxide nanoparticles for cardiac precursor cell selection from stromal vascular fraction and optimization for magnetic resonance imaging

    PubMed Central

    Verma, Vinod Kumar; Kamaraju, Suguna Ratnakar; Kancherla, Ravindranath; Kona, Lakshmi K; Beevi, Syed Sultan; Debnath, Tanya; Usha, Shalini P; Vadapalli, Rammohan; Arbab, Ali Syed; Chelluri, Lakshmi Kiran

    2015-01-01

    Fluorescent magnetic iron oxide nanoparticles have been used to label cells for imaging as well as for therapeutic purposes. The purpose of this study was to modify the approach to develop a nanoprobe for cell selection and imaging with a direct therapeutic translational focus. The approach involves physical coincubation and adsorption of superparamagnetic iron oxide nanoparticle-polyethylene glycol (SPION-PEG) complexes with a monoclonal antibody (mAb) or a set of antibodies. Flow cytometry, confocal laser scanning microscopy, transmission electron microscopy, iron staining, and magnetic resonance imaging were used to assess cell viability, function, and labeling efficiency. This process has been validated by selecting adipose tissue-derived cardiac progenitor cells from the stromal vascular fraction using signal regulatory protein alpha (SIRPA)/kinase domain receptor (KDR) mAbs. These markers were chosen because of their sustained expression during cardiomyocyte differentiation. Sorting of cells positive for SIRPA and KDR allowed the enrichment of cardiac progenitors with 90% troponin-I positivity in differentiation cultures. SPION labeled cardiac progenitor cells (1×105 cells) was mixed with gel and used for 3T magnetic resonance imaging at a concentration, as low as 12.5 μg of iron. The toxicity assays, at cellular and molecular levels, did not show any detrimental effects of SPION. Our study has the potential to achieve moderate to high specific cell selection for the dual purpose of imaging and therapy. PMID:25653519

  8. Combining short-axis and long-axis cardiac MR images by applying a super-resolution reconstruction algorithm

    NASA Astrophysics Data System (ADS)

    Rahman, Sami u.; Wesarg, Stefan

    2010-03-01

    In cardiac MR images the slice thickness is normally greater than the pixel size within the slices. In general, better segmentation and analysis results can be expected for isotropic high-resolution (HR) data sets. If two orthogonal data sets, e. g. short-axis (SA) and long-axis (LA) volumes are combined, an increase in resolution can be obtained. In this work we employ a super-resolution reconstruction (SRR) algorithm for computing high-resolution data sets from two orthogonal SA and LA volumes. In contrast to a simple averaging of both data in the overlapping region, we apply a maximum a posteriori approach. There, an observation model is employed for estimating an HR image that best reproduces the two low-resolution input data sets. For testing the SRR approach, we use clinical MRI data with an in-plane resolution of 1.5 mm×1.5 mm and a slice thickness of 8 mm. We show that the results obtained with our approach are superior to currently used averaging techniques. Due to the fact that the heart deforms over the cardiac cycle, we investigate further, how the replacement of a rigid registration by a deformable registration as preprocessing step improves the quality of the final HR image data. We conclude that image quality is dramatically enhanced by applying an SRR technique especially for cardiac MR images where the resolution in slice-selection direction is about five times lower than within the slices.

  9. Aorta segmentation in non-contrast cardiac CT images using an entropy-based cost function

    NASA Astrophysics Data System (ADS)

    Avila-Montes, Olga C.; Kukure, Uday; Kakadiaris, Ioannis A.

    2010-03-01

    Studies have shown that aortic calcification is associated with increased risk of cardiovascular disease. Furthermore, aortic calcium assessment can be performed on standard cardiac calcium scoring Computed Tomography scans, which may help to avoid additional imaging studies. In this paper, we present an entropy-based, narrow band restricted, iterative method for segmentation of the ascending aorta in non-contrast CT images, as a step towards aortic calcification detection and pericardial fat quantitation. First, an estimate of the aorta center and radius is obtained by applying dynamic programming in Hough space. In the second step, these estimates serve to reduce the aorta boundary search area to within a narrow band, and the contour is updated iteratively using dynamic programming methods. Our algorithm is able to overcome the limitations of previous approaches in characterizing (i) the boundary edge features and (ii) non-circular shape at aortic root. The results from the proposed method compare favorably with the manually traced aorta boundaries and outperform other approaches in terms of boundary distance and volume overlap.

  10. Robust image-based estimation of cardiac tissue parameters and their uncertainty from noisy data.

    PubMed

    Neumann, Dominik; Mansi, Tommaso; Georgescu, Bogdan; Kamen, Ali; Kayvanpour, Elham; Amr, Ali; Sedaghat-Hamedani, Farbod; Haas, Jan; Katus, Hugo; Meder, Benjamin; Hornegger, Joachim; Comaniciu, Dorin

    2014-01-01

    Clinical applications of computational cardiac models require precise personalization, i.e. fitting model parameters to capture patient's physiology. However, due to parameter non-identifiability, limited data, uncertainty in the clinical measurements, and modeling assumptions, various combinations of parameter values may exist that yield the same quality of fit. Hence, there is a need for quantifying the uncertainty in estimated parameters and to ascertain the uniqueness of the found solution. This paper presents a stochastic method to estimate the parameters of an image-based electromechanical model of the heart and their uncertainty due to noise in measurements. First, Bayesian inference is applied to fully estimate the posterior probability density function (PDF) of the model. To that end, Markov Chain Monte Carlo sampling is used, which is made computationally tractable by employing a fast surrogate model based on Polynomial Chaos Expansion, instead of the true forward model. Then, we use the mean-shift algorithm to automatically find the modes of the PDF and select the most likely one while being robust to noise. The approach is used to estimate global active stress and passive stiffness from invasive pressure and image-based volume quantification. Experiments on eight patients showed that not only our approach yielded goodness of fits equivalent to a well-established deterministic method, but we could also demonstrate the non-uniqueness of the problem and report uncertainty estimates, crucial information for subsequent clinical assessments of the personalized models. PMID:25485357

  11. Quality of myocardial perfusion single-photon emission tomography imaging: multicentre evaluation with a cardiac phantom.

    PubMed

    Heikkinen, J; Ahonen, A; Kuikka, J T; Rautio, P

    1999-10-01

    The aim of the study was to evaluate quality of myocardial perfusion single-photon emission tomography (SPET) imaging in Finnish hospitals. Nineteen nuclear medicine departments participated in the study. A myocardial phantom simulating clinical stress and rest conditions was filled with routinely used isotope solution (technetium-99m or thallium-201). The cardiac insert included three reversible defects (simulating ischaemia): 30x30x14 mm(3) septal (90% recovery at rest), 30x20x14 mm(3) posterobasal (full recovery) and 20x20x14 mm(3) lateral (full recovery). There were two fixed defects (simulating infarct): 30x20x14 mm(3) postero-apical and 10x10x6 mm(3) apical. The phantom was imaged and interpreted as a myocardial perfusion patient. Reconstruction, printout and reporting were performed according to the clinical routine of each centre. Three nuclear medicine specialists anonymously evaluated the quality of the image sets. The visual scores of the experts were ranked from 1 to 5. Additionally, points from 0 to 8 were given to research reports according to how well perfusion defects were detected. Quantitative points were calculated by comparing background-subtracted and -normalized counts from 12 regions of interest between stress and rest images. Results for technetium studies (12 departments) were better than those for thallium (7 departments). The average visual scores of the experts were 3.7+/-0. 9 for all image sets, 3.2+/-0.5 for thallium users and 3.9+/-0.6 for technetium users (P=0.003). Five laboratories received a low score which, according to the specialists, is barely sufficient for limited clinical use. Average points for the reports were 5.6+/-2.1, 4.9+/-1.5 and 6.5+/-1.7 (P=0.051), and for the quantitation 8.2+/-1. 0, 7.9+/-0.4 and 8.4+/-1.1 (P=0.185), respectively. Seven out of 22 interpreters did not detect the lateral 20x20x14 mm(3) defect; five of them used thallium. This study demonstrated the heterogeneity of myocardial perfusion SPET in

  12. Hybridization-based aptamer labeling using complementary oligonucleotide platform for PET and optical imaging.

    PubMed

    Park, Jun Young; Lee, Tae Sup; Song, In Ho; Cho, Ye Lim; Chae, Ju Ri; Yun, Mijin; Kang, Hyungu; Lee, Jung Hwan; Lim, Jong Hoon; Cho, Won Gil; Kang, Won Jun

    2016-09-01

    Aptamers are promising next-generation ligands used in molecular imaging and theragnosis. Aptamers are synthetic nucleic acids that can be held together with complementary sequences by base-pair hybridization. In this study, the complementary oligonucleotide (cODN) hybridization-based aptamer conjugation platform was developed to use aptamers as the molecular imaging agent. The cODN was pre-labeled with fluorescent dye or radioisotope and hybridized with a matched sequence containing aptamers in aqueous conditions. The cODN platform-hybridized aptamers exhibited good serum stability and specific binding affinity towards target cancer cells both in vitro and in vivo. These results suggest that the newly designed aptamer conjugation platform offers great potential for the versatile application of aptamers as molecular imaging agents. PMID:27258484

  13. Stress Cardiac Magnetic Resonance Imaging With Observation Unit Care Reduces Cost for Patients With Emergent Chest Pain: A Randomized Trial

    PubMed Central

    Miller, Chadwick D.; Hwang, Wenke; Hoekstra, James W.; Case, Doug; Lefebvre, Cedric; Blumstein, Howard; Hiestand, Brian; Diercks, Deborah B.; Hamilton, Craig A.; Harper, Erin N.; Hundley, W. Gregory

    2013-01-01

    Study objective We determine whether imaging with cardiac magnetic resonance imaging (MRI) in an observation unit would reduce medical costs among patients with emergent non-low-risk chest pain who otherwise would be managed with an inpatient care strategy. Methods Emergency department patients (n=110) at intermediate or high probability for acute coronary syndrome without electrocardiographic or biomarker evidence of a myocardial infarction provided consent and were randomized to stress cardiac MRI in an observation unit versus standard inpatient care. The primary outcome was direct hospital cost calculated as the sum of hospital and provider costs. Estimated median cost differences (Hodges-Lehmann) and distribution-free 95% confidence intervals (Moses) were used to compare groups. Results There were 110 participants with 53 randomized to cardiac MRI and 57 to inpatient care; 8 of 110 (7%) experienced acute coronary syndrome. In the MRI pathway, 49 of 53 underwent stress cardiac MRI, 11 of 53 were admitted, 1 left against medical advice, 41 were discharged, and 2 had acute coronary syndrome. In the inpatient care pathway, 39 of 57 patients initially received stress testing, 54 of 57 were admitted, 3 left against medical advice, and 6 had acute coronary syndrome. At 30 days, no subjects in either group experienced acute coronary syndrome after discharge. The cardiac MRI group had a reduced median hospitalization cost (Hodges-Lehmann estimate $588; 95% confidence interval $336 to $811); 79% were managed without hospital admission. Conclusion Compared with inpatient care, an observation unit strategy involving stress cardiac MRI reduced incident cost without any cases of missed acute coronary syndrome in patients with emergent chest pain. PMID:20554078

  14. Imaging of cardiac perfusion of free-breathing small animals using dynamic phase-correlated micro-CT

    SciTech Connect

    Sawall, Stefan; Kuntz, Jan; Socher, Michaela; Knaup, Michael; Hess, Andreas; Bartling, Soenke; Kachelriess, Marc

    2012-12-15

    Purpose:Mouse models of cardiac diseases have proven to be a valuable tool in preclinical research. The high cardiac and respiratory rates of free breathing mice prohibit conventional in vivo cardiac perfusion studies using computed tomography even if gating methods are applied. This makes a sacrification of the animals unavoidable and only allows for the application of ex vivo methods. Methods: To overcome this issue the authors propose a low dose scan protocol and an associated reconstruction algorithm that allows for in vivo imaging of cardiac perfusion and associated processes that are retrospectively synchronized to the respiratory and cardiac motion of the animal. The scan protocol consists of repetitive injections of contrast media within several consecutive scans while the ECG, respiratory motion, and timestamp of contrast injection are recorded and synchronized to the acquired projections. The iterative reconstruction algorithm employs a six-dimensional edge-preserving filter to provide low-noise, motion artifact-free images of the animal examined using the authors' low dose scan protocol. Results: The reconstructions obtained show that the complete temporal bolus evolution can be visualized and quantified in any desired combination of cardiac and respiratory phase including reperfusion phases. The proposed reconstruction method thereby keeps the administered radiation dose at a minimum and thus reduces metabolic inference to the animal allowing for longitudinal studies. Conclusions: The authors' low dose scan protocol and phase-correlated dynamic reconstruction algorithm allow for an easy and effective way to visualize phase-correlated perfusion processes in routine laboratory studies using free-breathing mice.

  15. Contour definition and tracking in cardiac imaging through the integration of knowledge and image evidence.

    PubMed

    Baroni, Maurizio; Barletta, Giuseppe

    2004-05-01

    The main contribution of this paper is the use of simple processing techniques, incorporated in a new multistage approach, to automatically delineate left ventricle contours. Another contribution is the proposal of the centerline distances for contour comparison, which promises a more accurate measurement than the common method, based on the distance to the closest point. Edges are detected by Gaussian filtering at coarse and fine scale. The region of interest is defined as a binary map where coarse edges are extracted throughout image sequence. A contour template is matched against the gradient of the first image. Candidate boundary points are instantiated by scanning the coarse edge map perpendicularly to the matched template. A candidate contour is estimated from these points by maximizing an edge likelihood function. A region growing algorithm gives another candidate contour. Both edge and region candidate contours are then integrated with the edge map computed at fine scale by maximizing another likelihood function. Evaluation was carried out on 12 echocardiographic and 4 angiocardiographic sequences (for a total of 289 frames). Distances between computer-generated contours and the contours traced by three experts were within interobserver variability, unlike the results obtained by Acoustic Quantification and by a general-purpose deformable model.

  16. Individual sarcomere length determination from isolated cardiac cells using high-resolution optical microscopy and digital image processing.

    PubMed Central

    Roos, K P; Brady, A J

    1982-01-01

    Discrete sarcomere lengths have been determined from dynamically contracting isolated cardiac cells with a high-speed, high-resolution direct optical imaging system. Calcium-tolerant cardiac cells from the rat are isolated by perfusion with collagenase and hyaluronidase. Individual sarcomere lengths can be determined by directly imaging the cell's striation pattern onto a solid-state charge-coupled device (CCD) detector interfaced with a digital computer. The precision of detection in a real light microscopic optical system is discussed in relation to the type of image detector, optical contract enhancement techniques, and digital image processing. The optical performance of the direct striation pattern image apparatus has been determined empirically with test grids under standard bright-field and Nomarski-differential interference contrast (DIC) conditions for application to real muscle imaging. Discrete striation positions of isolated cells have been detected and followed with high precision during phasic contraction-relaxation cycles down to average sarcomere lengths as short as 1.43 +/- 0.053 microns. The maximum rates of contraction and relaxation are rapid and synchronous in time course along the length of the cell. These results indicate that direct optical imaging can provide an accurate means to monitor discrete striations and sarcomere lengths along the length of Ca2+-tolerant heart cells. Images FIGURE 1 FIGURE 4 PMID:7183337

  17. Automatic computation of left ventricular volume changes over a cardiac cycle from echocardiography images by nonlinear dimensionality reduction.

    PubMed

    Alizadeh Sani, Zahra; Shalbaf, Ahmad; Behnam, Hamid; Shalbaf, Reza

    2015-02-01

    Curve of left ventricular (LV) volume changes throughout the cardiac cycle is a fundamental parameter for clinical evaluation of various cardiovascular diseases. Currently, this evaluation is often performed manually which is tedious and time consuming and suffers from significant interobserver and intraobserver variability. This paper introduces a new automatic method, based on nonlinear dimensionality reduction (NLDR) for extracting the curve of the LV volume changes over a cardiac cycle from two-dimensional (2-D) echocardiography images. Isometric feature mapping (Isomap) is one of the most popular NLDR algorithms. In this study, a modified version of Isomap algorithm, where image to image distance metric is computed using nonrigid registration, is applied on 2-D echocardiography images of one cycle of heart. Using this approach, the nonlinear information of these images is embedded in a 2-D manifold and each image is characterized by a symbol on the constructed manifold. This new representation visualizes the relationship between these images based on LV volume changes and allows extracting the curve of the LV volume changes automatically. Our method in comparison to the traditional segmentation algorithms does not need any LV myocardial segmentation and tracking, particularly difficult in the echocardiography images. Moreover, a large data set under various diseases for training is not required. The results obtained by our method are quantitatively evaluated to those obtained manually by the highly experienced echocardiographer on ten healthy volunteers and six patients which depict the usefulness of the presented method.

  18. Locally homogenized and de-noised vector fields for cardiac fiber tracking in DT-MRI images

    NASA Astrophysics Data System (ADS)

    Akhbardeh, Alireza; Vadakkumpadan, Fijoy; Bayer, Jason; Trayanova, Natalia A.

    2009-02-01

    In this study we develop a methodology to accurately extract and visualize cardiac microstructure from experimental Diffusion Tensor (DT) data. First, a test model was constructed using an image-based model generation technique on Diffusion Tensor Magnetic Resonance Imaging (DT-MRI) data. These images were derived from a dataset having 122x122x500 um3 voxel resolution. De-noising and image enhancement was applied to this high-resolution dataset to clearly define anatomical boundaries within the images. The myocardial tissue was segmented from structural images using edge detection, region growing, and level set thresholding. The primary eigenvector of the diffusion tensor for each voxel, which represents the longitudinal direction of the fiber, was calculated to generate a vector field. Then an advanced locally regularizing nonlinear anisotropic filter, termed Perona-Malik (PEM), was used to regularize this vector field to eliminate imaging artifacts inherent to DT-MRI from volume averaging of the tissue with the surrounding medium. Finally, the vector field was streamlined to visualize fibers within the segmented myocardial tissue to compare the results with unfiltered data. With this technique, we were able to recover locally regularized (homogenized) fibers with a high accuracy by applying the PEM regularization technique, particularly on anatomical surfaces where imaging artifacts were most apparent. This approach not only aides in the visualization of noisy complex 3D vector fields obtained from DT-MRI, but also eliminates volume averaging artifacts to provide a realistic cardiac microstructure for use in electrophysiological modeling studies.

  19. 3D Multi-Object Segmentation of Cardiac MSCT Imaging by using a Multi-Agent Approach

    PubMed Central

    Fleureau, Julien; Garreau, Mireille; Boulmier, Dominique; Hernandez, Alfredo

    2007-01-01

    We propose a new technique for general purpose, semi-interactive and multi-object segmentation in N-dimensional images, applied to the extraction of cardiac structures in MultiSlice Computed Tomography (MSCT) imaging. The proposed approach makes use of a multi-agent scheme combined with a supervised classification methodology allowing the introduction of a priori information and presenting fast computing times. The multi-agent system is organised around a communicating agent which manages a population of situated agents which segment the image through cooperative and competitive interactions. The proposed technique has been tested on several patient data sets. Some typical results are finally presented and discussed. PMID:18003382

  20. Comparative Performance Of A Standard And High Line Rate Video Imaging System In A Cardiac Catherization Laboratory

    NASA Astrophysics Data System (ADS)

    Rossi, Raymond P.; Ahrens, Charles; Groves, Bertron M.

    1985-09-01

    The performance of a new high line rate (1023) video imaging system (VHR) installed in the cardiac catherization laboratory at the University of Colorado Health Sciences Center is compared to the previously installed standard line rate (525) video imaging system (pre-VHR). Comparative performance was assessed both quantitatively using a standardized evaluation protocol and qualitatively based on analysis of data collected during the observation of clinical procedures for which the cardiologists were asked to rank the quality of the fluoroscopic image. The results of this comparative study are presented and suggest that the performance of the high line rate system is significantly improved over the standard line rate system.

  1. Hybrid bronchoscope tracking using a magnetic tracking sensor and image registration.

    PubMed

    Mori, Kensaku; Deguchi, Daisuke; Akiyama, Kenta; Kitasaka, Takayuki; Maurer, Calvin R; Suenaga, Yasuhito; Takabatake, Hirotsugu; Mori, Masaki; Natori, Hiroshi

    2005-01-01

    In this paper, we propose a hybrid method for tracking a bronchoscope that uses a combination of magnetic sensor tracking and image registration. The position of a magnetic sensor placed in the working channel of the bronchoscope is provided by a magnetic tracking system. Because of respiratory motion, the magnetic sensor provides only the approximate position and orientation of the bronchoscope in the coordinate system of a CT image acquired before the examination. The sensor position and orientation is used as the starting point for an intensity-based registration between real bronchoscopic video images and virtual bronchoscopic images generated from the CT image. The output transformation of the image registration process is the position and orientation of the bronchoscope in the CT image. We tested the proposed method using a bronchial phantom model. Virtual breathing motion was generated to simulate respiratory motion. The proposed hybrid method successfully tracked the bronchoscope at a rate of approximately 1 Hz.

  2. Multimodality Molecular Imaging of Cardiac Cell Transplantation: Part II. In Vivo Imaging of Bone Marrow Stromal Cells in Swine with PET/CT and MR Imaging.

    PubMed

    Parashurama, Natesh; Ahn, Byeong-Cheol; Ziv, Keren; Ito, Ken; Paulmurugan, Ramasamy; Willmann, Jürgen K; Chung, Jaehoon; Ikeno, Fumiaki; Swanson, Julia C; Merk, Denis R; Lyons, Jennifer K; Yerushalmi, David; Teramoto, Tomohiko; Kosuge, Hisanori; Dao, Catherine N; Ray, Pritha; Patel, Manishkumar; Chang, Ya-Fang; Mahmoudi, Morteza; Cohen, Jeff Eric; Goldstone, Andrew Brooks; Habte, Frezghi; Bhaumik, Srabani; Yaghoubi, Shahriar; Robbins, Robert C; Dash, Rajesh; Yang, Phillip C; Brinton, Todd J; Yock, Paul G; McConnell, Michael V; Gambhir, Sanjiv S

    2016-09-01

    Purpose To quantitatively determine the limit of detection of marrow stromal cells (MSC) after cardiac cell therapy (CCT) in swine by using clinical positron emission tomography (PET) reporter gene imaging and magnetic resonance (MR) imaging with cell prelabeling. Materials and Methods Animal studies were approved by the institutional administrative panel on laboratory animal care. Seven swine received 23 intracardiac cell injections that contained control MSC and cell mixtures of MSC expressing a multimodality triple fusion (TF) reporter gene (MSC-TF) and bearing superparamagnetic iron oxide nanoparticles (NP) (MSC-TF-NP) or NP alone. Clinical MR imaging and PET reporter gene molecular imaging were performed after intravenous injection of the radiotracer fluorine 18-radiolabeled 9-[4-fluoro-3-(hydroxyl methyl) butyl] guanine ((18)F-FHBG). Linear regression analysis of both MR imaging and PET data and nonlinear regression analysis of PET data were performed, accounting for multiple injections per animal. Results MR imaging showed a positive correlation between MSC-TF-NP cell number and dephasing (dark) signal (R(2) = 0.72, P = .0001) and a lower detection limit of at least approximately 1.5 × 10(7) cells. PET reporter gene imaging demonstrated a significant positive correlation between MSC-TF and target-to-background ratio with the linear model (R(2) = 0.88, P = .0001, root mean square error = 0.523) and the nonlinear model (R(2) = 0.99, P = .0001, root mean square error = 0.273) and a lower detection limit of 2.5 × 10(8) cells. Conclusion The authors quantitatively determined the limit of detection of MSC after CCT in swine by using clinical PET reporter gene imaging and clinical MR imaging with cell prelabeling. (©) RSNA, 2016 Online supplemental material is available for this article. PMID:27332865

  3. Feasibility study to demonstrate cardiac imaging using fast kVp switching dual-energy computed tomography: phantom study

    NASA Astrophysics Data System (ADS)

    Madhav, Priti; Imai, Yasuhiro; Narayanan, Suresh; Dutta, Sandeep; Chandra, Naveen; Hsieh, Jiang

    2012-03-01

    Dual-energy computed tomography is a novel imaging tool that has the potential to reduce beam hardening artifacts and enhance material separation over conventional imaging techniques. Dual-energy acquisitions can be performed by using a fast kVp technology to switch between acquiring adjacent projections at two distinct x-ray spectra (80 and 140 kVp). These datasets can be used to further compute material density and monochromatic images for better material separation and beam hardening reduction by virtue of the projection domain process. The purpose of this study was to evaluate the feasibility of using dual-energy in cardiac imaging for myocardial perfusion detection and coronary artery lumen visualization. Data was acquired on a heart phantom, which consisted of the chambers and aorta filled with Iodine density solution (500 HU @ 120 kVp), a defect region between the aorta and chamber (40 HU @ 120 kVp), two Iodinefilled vessels (400 HU @ 120 kVp) of different diameters with high attenuation (hydroxyapatite) plaques (HAP), and with a 30-cm water equivalent body ring around the phantom. Prospective ECG-gated single-energy and prospective ECG-gated dual-energy imaging was performed. Results showed that the generated monochromatic images had minimal beam hardening artifacts which improved the accuracy and detection of the myocardial defect region. Material density images were useful in differentiating and quantifying the actual size of the plaque and coronary artery lumen. Overall, this study shows that dual-energy cardiac imaging will be a valuable tool for cardiac applications.

  4. Adenosine-stress cardiac magnetic resonance imaging in suspected coronary artery disease: a net cost analysis and reimbursement implications.

    PubMed

    Pilz, Guenter; Patel, Pankaj A; Fell, Ulrich; Ladapo, Joseph A; Rizzo, John A; Fang, Hai; Gunnarsson, Candace; Heer, Tobias; Hoefling, Berthold

    2011-01-01

    The health and economic implications of new imaging technologies are increasingly relevant policy issues. Cardiac magnetic resonance imaging (CMR) is currently not or not sufficiently reimbursed in a number of countries including Germany, presumably because of a limited evidence base. It is unknown, however, whether it can be effectively used to facilitate medical decision-making and reduce costs by serving as a gatekeeper to invasive coronary angiography. We investigated whether the application of CMR in patients suspected of having coronary artery disease (CAD) reduces costs by averting referrals to cardiac catheterization. We used propensity score methods to match 218 patients from a CMR registry to a previously studied cohort in which CMR was demonstrated to reliably identify patients who were low-risk for major cardiac events. Covariates over which patients were matched included comorbidity profiles, demographics, CAD-related symptoms, and CAD risk as measured by Morise scores. We determined the proportion of patients for whom cardiac catheterization was deferred based upon CMR findings. We then calculated the economic effects of practice pattern changes using data on cardiac catheterization and CMR costs. CMR reduced the utilization of cardiac catheterization by 62.4%. Based on estimated catheterization costs of € 619, the utilization of CMR as a gatekeeper reduced per-patient costs by a mean of € 90. Savings were realized until CMR costs exceeded € 386. Cost savings were greatest for patients at low-risk for CAD, as measured by baseline Morise scores, but were present for all Morise subgroups with the exception of patients at the highest risk of CAD. CMR significantly reduces the utilization of cardiac catheterization in patients suspected of having CAD. Per-patient savings range from € 323 in patients at lowest risk of CAD to € 58 in patients at high-risk but not in the highest risk stratum. Because a negative CMR evaluation has high negative

  5. Application of the Karhunen-Loeve transform temporal image filter to reduce noise in real-time cardiac cine MRI

    NASA Astrophysics Data System (ADS)

    Ding, Yu; Chung, Yiu-Cho; Raman, Subha V.; Simonetti, Orlando P.

    2009-06-01

    Real-time dynamic magnetic resonance imaging (MRI) typically sacrifices the signal-to-noise ratio (SNR) to achieve higher spatial and temporal resolution. Spatial and/or temporal filtering (e.g., low-pass filtering or averaging) of dynamic images improves the SNR at the expense of edge sharpness. We describe the application of a temporal filter for dynamic MR image series based on the Karhunen-Loeve transform (KLT) to remove random noise without blurring stationary or moving edges and requiring no training data. In this paper, we present several properties of this filter and their effects on filter performance, and propose an automatic way to find the filter cutoff based on the autocorrelation of the eigenimages. Numerical simulation and in vivo real-time cardiac cine MR image series spanning multiple cardiac cycles acquired using multi-channel sensitivity-encoded MRI, i.e., parallel imaging, are used to validate and demonstrate these properties. We found that in this application, the noise standard deviation was reduced to 42% of the original with no apparent image blurring by using the proposed filter cutoff. Greater noise reduction can be achieved by increasing the length of the image series. This advantage of KLT filtering provides flexibility in the form of another scan parameter to trade for SNR.

  6. A three-dimensional model-based partial volume correction strategy for gated cardiac mouse PET imaging

    NASA Astrophysics Data System (ADS)

    Dumouchel, Tyler; Thorn, Stephanie; Kordos, Myra; DaSilva, Jean; Beanlands, Rob S. B.; deKemp, Robert A.

    2012-07-01

    Quantification in cardiac mouse positron emission tomography (PET) imaging is limited by the imaging spatial resolution. Spillover of left ventricle (LV) myocardial activity into adjacent organs results in partial volume (PV) losses leading to underestimation of myocardial activity. A PV correction method was developed to restore accuracy of the activity distribution for FDG mouse imaging. The PV correction model was based on convolving an LV image estimate with a 3D point spread function. The LV model was described regionally by a five-parameter profile including myocardial, background and blood activities which were separated into three compartments by the endocardial radius and myocardium wall thickness. The PV correction was tested with digital simulations and a physical 3D mouse LV phantom. In vivo cardiac FDG mouse PET imaging was also performed. Following imaging, the mice were sacrificed and the tracer biodistribution in the LV and liver tissue was measured using a gamma-counter. The PV correction algorithm improved recovery from 50% to within 5% of the truth for the simulated and measured phantom data and image uniformity by 5-13%. The PV correction algorithm improved the mean myocardial LV recovery from 0.56 (0.54) to 1.13 (1.10) without (with) scatter and attenuation corrections. The mean image uniformity was improved from 26% (26%) to 17% (16%) without (with) scatter and attenuation corrections applied. Scatter and attenuation corrections were not observed to significantly impact PV-corrected myocardial recovery or image uniformity. Image-based PV correction algorithm can increase the accuracy of PET image activity and improve the uniformity of the activity distribution in normal mice. The algorithm may be applied using different tracers, in transgenic models that affect myocardial uptake, or in different species provided there is sufficient image quality and similar contrast between the myocardium and surrounding structures.

  7. Evolution of cardiac imaging according to the number of scientific articles in medical journals: a long and fruitful journey.

    PubMed

    Garcia-Fernandez, Miguel Angel

    2014-11-01

    The use of cardiac imaging techniques as a diagnostic method in the understanding of physiopathology, as well as in cardiology research has been one of the most important revolutions in the management of cardiac patients, our understanding of physiopathology, and basic research in almost all heart diseases. This article analyzes the literature on echocardiography, cardiovascular magnetic resonance imaging, computed tomography, and nuclear medicine during the last 60 years and provides an overview of how these techniques have developed and how their introduction into daily practice has changed attitudes among cardiologists. The literature not only shows that the implementation of these techniques in daily practice requires an immense amount of research and effort by many working groups throughout the scientific world, but also that techniques that once seemed promising may finally be discarded.

  8. Cardiac imaging using clinical 1.5 t MRI scanners in a murine ischemia/reperfusion model.

    PubMed

    Voelkl, Jakob G J; Haubner, Bernhard J; Kremser, Christian; Mayr, Agnes; Klug, Gert; Loizides, Alexander; Müller, Silvana; Pachinger, Otmar; Schocke, Michael; Metzler, Bernhard

    2011-01-01

    To perform cardiac imaging in mice without having to invest in expensive dedicated equipment, we adapted a clinical 1.5 Tesla (T) magnetic resonance imaging (MRI) scanner for use in a murine ischemia/reperfusion model. Phase-sensitive inversion recovery (PSIR) sequence facilitated the determination of infarct sizes in vivo by late gadolinium enhancement. Results were compared to histological infarct areas in mice after ischemia/reperfusion procedure with a good correlation (r = 0.807, P < .001). In addition, fractional area change (FAC) was assessed with single slice cine MRI and was matched to infarct size (r = -0.837) and fractional shortening (FS) measured with echocardiography (r = 0.860); both P < .001. Here, we demonstrate the use of clinical 1.5 MRI scanners as a feasible method for basic phenotyping in mice. These widely available scanners are capable of investigating in vivo infarct dimensions as well as assessment of cardiac functional parameters in mice with reasonable throughput.

  9. Hybrid Compton camera/coded aperture imaging system

    DOEpatents

    Mihailescu, Lucian; Vetter, Kai M.

    2012-04-10

    A system in one embodiment includes an array of radiation detectors; and an array of imagers positioned behind the array of detectors relative to an expected trajectory of incoming radiation. A method in another embodiment includes detecting incoming radiation with an array of radiation detectors; detecting the incoming radiation with an array of imagers positioned behind the array of detectors relative to a trajectory of the incoming radiation; and performing at least one of Compton imaging using at least the imagers and coded aperture imaging using at least the imagers. A method in yet another embodiment includes detecting incoming radiation with an array of imagers positioned behind an array of detectors relative to a trajectory of the incoming radiation; and performing Compton imaging using at least the imagers.

  10. Four-dimensional superquadric-based cardiac phantom for Monte Carlo simulation of radiological imaging systems

    SciTech Connect

    Peter, J.; Gilland, D.R.; Jaszczak, R.J.; Coleman, R.E.

    1999-12-01

    A four-dimensional (x, y, z, t) composite superquadric-based object model of the human heart for Monte Carlo simulation of radiological imaging systems has been developed. The phantom models the real temporal geometric conditions of a beating heart for frame rates up to 32 per cardiac cycle. Phantom objects are described by boolean combinations of superquadric ellipsoid sections.Moving spherical coordinate systems are chosen to model wall movement whereby points of the ventricle and atria walls are assumed to move towards a moving center-of-gravity point. Due to the non-static coordinate systems, the atrial/ventricular valve plane of the mathematical heart phantom moves up and down along the left ventricular long axis resulting in reciprocal emptying and filling of atria and ventricles. Compared to the base movement, the epicardial apex as well as the superior atria area are almost fixed in space. Since geometric parameters of the objects are directly applied on intersection calculations of the photon ray with object boundaries during Monte Carlo simulation, no phantom discretization artifacts are involved.

  11. Maximizing throughput in label-free microspectroscopy with hybrid Raman imaging

    NASA Astrophysics Data System (ADS)

    Pavillon, Nicolas; Smith, Nicholas I.

    2015-01-01

    Raman spectroscopy is an optical method providing sample molecular composition, which can be analyzed (by point measurements) or spatially mapped by Raman imaging. These provide different information, signal-to-noise ratios, and require different acquisition times. Here, we quantitatively assess Raman spectral features and compare the two measurement methods by multivariate analysis. We also propose a hybrid method: scanning the beam through the sample but optically binning the signal at one location on the detector. This approach generates significantly more useful spectral signals in terms of peak visibility and statistical information. Additionally, by combination with a complementary imaging mode such as quantitative phase microscopy, hybrid imaging allows high throughput and robust spectral analysis while retaining sample spatial information. We demonstrate the improved ability to discriminate between cell lines when using hybrid scanning compared to typical point mode measurements, by quantitatively evaluating spectra taken from two macrophage-like cell lines. Hybrid scanning also provides better classification capability than the full Raman imaging mode, while providing higher signal-to-noise signals with shorter acquisition times. This hybrid imaging approach is suited for various applications including cytometry, cancer versus noncancer detection, and label-free discrimination of cell types or tissues.

  12. Nanogel-quantum dot hybrid nanoparticles for live cell imaging

    SciTech Connect

    Hasegawa, Urara; Nomura, Shin-ichiro M.; Kaul, Sunil C.; Hirano, Takashi; Akiyoshi, Kazunari; E-mail: akiyoshi.org@tmd.ac.jp

    2005-06-17

    We report here a novel carrier of quantum dots (QDs) for intracellular labeling. Monodisperse hybrid nanoparticles (38 nm in diameter) of QDs were prepared by simple mixing with nanogels of cholesterol-bearing pullulan (CHP) modified with amino groups (CHPNH{sub 2}). The CHPNH{sub 2}-QD nanoparticles were effectively internalized into the various human cells examined. The efficiency of cellular uptake was much higher than that of a conventional carrier, cationic liposome. These hybrid nanoparticles could be a promising fluorescent probe for bioimaging.

  13. Cardiac and Hepatic T2*-Weighted Magnetic Resonance Imaging in Transfusion Dependent Hemoglobinopathy in North West of Iran

    PubMed Central

    Valizadeh, N; Alinejad, V; Hejazi, S; Noroozi, M; Hashemi, A; Rahimi, B; Nateghi, Sh

    2015-01-01

    Background Iron overload is the main transfusion related side effects in patients with transfusion dependent hemoglobinopathies. Severe iron deposition in tissues leads to organ dysfunction. Many organs can be affected such as heart, liver, and endocrine organs. Cardiac failure and liver fibrosis are the consequent of Iron overload in transfusion dependent hemoglobinopathy. Magnetic Resonance Imaging (MRI) is a safe, noninvasive, and accurate method for the assessment of iron deposition in different tissues. This study assessed iron levels in liver and heart of the patients with transfusion dependent hemoglobinopathies. Materials and Methods The studied population consisted of 12 patients (7 male and 5 female) with transfusion dependent hemoglobinopathies, aged between 10-18 years old. Then, Cardiac and liver T2*- weighted magnetic resonance imaging (MRI) were obtained. Results In current study, 1patient (8.33%) had severe, 2 patients (16.66%) had moderate and 2(16.66%) had mild cardiac iron deposition. Out of 12 patients, 1 had severe iron deposition in liver (8.33%), 5(41.66%) and 4(33.33%) had moderate and mild hepatic iron deposition, respectively. Differences between Hepatic and cardiac iron levels were not significant between males and females (p>0.05). Conclusion Since cardiac and liver iron levels were higher than normal in most of the study group, checking ferritin level and liver function test and also echocardiography in shorter intervals (each 3 months) in involved group is suggested instead of checking routinely in 6 month intervals in patients with transfusion dependent hemoglobinopathies. PMID:26985353

  14. Cardiac Light-Sheet Fluorescent Microscopy for Multi-Scale and Rapid Imaging of Architecture and Function

    PubMed Central

    Fei, Peng; Lee, Juhyun; Packard, René R. Sevag; Sereti, Konstantina-Ioanna; Xu, Hao; Ma, Jianguo; Ding, Yichen; Kang, Hanul; Chen, Harrison; Sung, Kevin; Kulkarni, Rajan; Ardehali, Reza; Kuo, C.-C. Jay; Xu, Xiaolei; Ho, Chih-Ming; Hsiai, Tzung K.

    2016-01-01

    Light Sheet Fluorescence Microscopy (LSFM) enables multi-dimensional and multi-scale imaging via illuminating specimens with a separate thin sheet of laser. It allows rapid plane illumination for reduced photo-damage and superior axial resolution and contrast. We hereby demonstrate cardiac LSFM (c-LSFM) imaging to assess the functional architecture of zebrafish embryos with a retrospective cardiac synchronization algorithm for four-dimensional reconstruction (3-D space + time). By combining our approach with tissue clearing techniques, we reveal the entire cardiac structures and hypertrabeculation of adult zebrafish hearts in response to doxorubicin treatment. By integrating the resolution enhancement technique with c-LSFM to increase the resolving power under a large field-of-view, we demonstrate the use of low power objective to resolve the entire architecture of large-scale neonatal mouse hearts, revealing the helical orientation of individual myocardial fibers. Therefore, our c-LSFM imaging approach provides multi-scale visualization of architecture and function to drive cardiovascular research with translational implication in congenital heart diseases. PMID:26935567

  15. Cardiac Light-Sheet Fluorescent Microscopy for Multi-Scale and Rapid Imaging of Architecture and Function.

    PubMed

    Fei, Peng; Lee, Juhyun; Packard, René R Sevag; Sereti, Konstantina-Ioanna; Xu, Hao; Ma, Jianguo; Ding, Yichen; Kang, Hanul; Chen, Harrison; Sung, Kevin; Kulkarni, Rajan; Ardehali, Reza; Kuo, C-C Jay; Xu, Xiaolei; Ho, Chih-Ming; Hsiai, Tzung K

    2016-01-01

    Light Sheet Fluorescence Microscopy (LSFM) enables multi-dimensional and multi-scale imaging via illuminating specimens with a separate thin sheet of laser. It allows rapid plane illumination for reduced photo-damage and superior axial resolution and contrast. We hereby demonstrate cardiac LSFM (c-LSFM) imaging to assess the functional architecture of zebrafish embryos with a retrospective cardiac synchronization algorithm for four-dimensional reconstruction (3-D space + time). By combining our approach with tissue clearing techniques, we reveal the entire cardiac structures and hypertrabeculation of adult zebrafish hearts in response to doxorubicin treatment. By integrating the resolution enhancement technique with c-LSFM to increase the resolving power under a large field-of-view, we demonstrate the use of low power objective to resolve the entire architecture of large-scale neonatal mouse hearts, revealing the helical orientation of individual myocardial fibers. Therefore, our c-LSFM imaging approach provides multi-scale visualization of architecture and function to drive cardiovascular research with translational implication in congenital heart diseases. PMID:26935567

  16. Cardiac Light-Sheet Fluorescent Microscopy for Multi-Scale and Rapid Imaging of Architecture and Function

    NASA Astrophysics Data System (ADS)

    Fei, Peng; Lee, Juhyun; Packard, René R. Sevag; Sereti, Konstantina-Ioanna; Xu, Hao; Ma, Jianguo; Ding, Yichen; Kang, Hanul; Chen, Harrison; Sung, Kevin; Kulkarni, Rajan; Ardehali, Reza; Kuo, C.-C. Jay; Xu, Xiaolei; Ho, Chih-Ming; Hsiai, Tzung K.

    2016-03-01

    Light Sheet Fluorescence Microscopy (LSFM) enables multi-dimensional and multi-scale imaging via illuminating specimens with a separate thin sheet of laser. It allows rapid plane illumination for reduced photo-damage and superior axial resolution and contrast. We hereby demonstrate cardiac LSFM (c-LSFM) imaging to assess the functional architecture of zebrafish embryos with a retrospective cardiac synchronization algorithm for four-dimensional reconstruction (3-D space + time). By combining our approach with tissue clearing techniques, we reveal the entire cardiac structures and hypertrabeculation of adult zebrafish hearts in response to doxorubicin treatment. By integrating the resolution enhancement technique with c-LSFM to increase the resolving power under a large field-of-view, we demonstrate the use of low power objective to resolve the entire architecture of large-scale neonatal mouse hearts, revealing the helical orientation of individual myocardial fibers. Therefore, our c-LSFM imaging approach provides multi-scale visualization of architecture and function to drive cardiovascular research with translational implication in congenital heart diseases.

  17. A system for seismocardiography-based identification of quiescent heart phases: implications for cardiac imaging.

    PubMed

    Wick, Carson A; Su, Jin-Jyh; McClellan, James H; Brand, Oliver; Bhatti, Pamela T; Buice, Ashley L; Stillman, Arthur E; Tang, Xiangyang; Tridandapani, Srini

    2012-09-01

    Seismocardiography (SCG), a representation of mechanical heart motion, may more accurately determine periods of cardiac quiescence within a cardiac cycle than the electrically derived electrocardiogram (EKG) and, thus, may have implications for gating in cardiac computed tomography. We designed and implemented a system to synchronously acquire echocardiography, EKG, and SCG data. The device was used to study the variability between EKG and SCG and characterize the relationship between the mechanical and electrical activity of the heart. For each cardiac cycle, the feature of the SCG indicating Aortic Valve Closure was identified and its time position with respect to the EKG was observed. This position was found to vary for different heart rates and between two human subjects. A color map showing the magnitude of the SCG acceleration and computed velocity was derived, allowing for direct visualization of quiescent phases of the cardiac cycle with respect to heart rate. PMID:22581141

  18. [18F]-NaF PET/CT imaging in cardiac amyloidosis.

    PubMed

    Van Der Gucht, Axel; Galat, Arnault; Rosso, Jean; Guellich, Aziz; Garot, Jérôme; Bodez, Diane; Plante-Bordeneuve, Violaine; Hittinger, Luc; Dubois-Randé, Jean-Luc; Evangelista, Eva; Sasanelli, Myriam; Chalaye, Julia; Meignan, Michel; Itti, Emmanuel; Damy, Thibaud

    2016-08-01

    Cardiac amyloidosis (CA) is recognized as a common cause of restrictive cardiomyopathy and heart failure due to the deposition of insoluble proteins in the myocardial interstitium. We emphasize the role of [18F]-sodium fluoride (NaF) PET/CT as a potential noninvasive tool to identify and differentiate the transthyretin-related cardiac amyloidosis from the light-chain cardiac amyloidosis. We report cases of a 73-year-old man and a 75-year-old woman followed in our center for congestive heart failure with marked alteration of the left ventricular ejection fraction due to familial transthyretin Val122Ile cardiac amyloidosis and light-chain cardiac amyloidosis, respectively, confirmed on endomyocardial biopsy.

  19. A System for Seismocardiography-Based Identification of Quiescent Heart Phases: Implications for Cardiac Imaging

    PubMed Central

    Wick, Carson A.; Su, Jin-Jyh; McClellan, James H.; Brand, Oliver; Bhatti, Pamela T.; Buice, Ashley L.; Stillman, Arthur E.; Tang, Xiangyang; Tridandapani, Srini

    2013-01-01

    Seismocardiography (SCG), a representation of mechanical heart motion, may more accurately determine periods of cardiac quiescence within a cardiac cycle than the electrically derived electrocardiogram (EKG) and, thus, may have implications for gating in cardiac computed tomography. We designed and implemented a system to synchronously acquire echocardiography, EKG, and SCG data. The device was used to study the variability between EKG and SCG and characterize the relationship between the mechanical and electrical activity of the heart. For each cardiac cycle, the feature of the SCG indicating Aortic Valve Closure was identified and its time position with respect to the EKG was observed. This position was found to vary for different heart rates and between two human subjects. A color map showing the magnitude of the SCG acceleration and computed velocity was derived, allowing for direct visualization of quiescent phases of the cardiac cycle with respect to heart rate. PMID:22581141

  20. Appropriate Use of Cardiac Stress Testing with Imaging: A Systematic Review and Meta-Analysis

    PubMed Central

    Ladapo, Joseph A.; Blecker, Saul; O'Donnell, Michael; Jumkhawala, Saahil A.; Douglas, Pamela S.

    2016-01-01

    Background Appropriate use criteria (AUC) for cardiac stress tests address concerns about utilization growth and patient safety. We systematically reviewed studies of appropriateness, including within physician specialties; evaluated trends over time and in response to AUC updates; and characterized leading indications for inappropriate/rarely appropriate testing. Methods We searched PubMed (2005–2015) for English-language articles reporting stress echocardiography or myocardial perfusion imaging (MPI) appropriateness. Data were pooled using random-effects meta-analysis and meta-regression. Results Thirty-four publications of 41,578 patients were included, primarily from academic centers. Stress echocardiography appropriate testing rates were 53.0% (95% CI, 45.3%–60.7%) and 50.9% (42.6%–59.2%) and inappropriate/rarely appropriate rates were 19.1% (11.4%–26.8%) and 28.4% (23.9%–32.8%) using 2008 and 2011 AUC, respectively. Stress MPI appropriate testing rates were 71.1% (64.5%–77.7%) and 72.0% (67.6%–76.3%) and inappropriate/rarely appropriate rates were 10.7% (7.2%–14.2%) and 15.7% (12.4%–19.1%) using 2005 and 2009 AUC, respectively. There was no significant temporal trend toward rising rates of appropriateness for stress echocardiography or MPI. Unclassified stress echocardiograms fell by 79% (p = 0.04) with updated AUC. There were no differences between cardiac specialists and internists. Conclusions Rates of appropriate use tend to be lower for stress echocardiography compared to MPI, and updated AUC reduced unclassified stress echocardiograms. There is no conclusive evidence that AUC improved appropriate use over time. Further research is needed to determine if integration of appropriateness guidelines in academic and community settings is an effective approach to optimizing inappropriate/rarely appropriate use of stress testing and its associated costs and patient harms. PMID:27536775

  1. Acute Radiation Effects on Cardiac Function Detected by Strain Rate Imaging in Breast Cancer Patients

    SciTech Connect

    Erven, Katrien; Jurcut, Ruxandra; Weltens, Caroline; Giusca, Sorin; Ector, Joris; Wildiers, Hans; Van den Bogaert, Walter; Voigt, Jens-Uwe

    2011-04-01

    Purpose: To investigate the occurrence of early radiation-induced changes in regional cardiac function using strain rate imaging (SRI) by tissue Doppler echocardiography. Methods and Materials: We included 20 left-sided and 10 right-sided breast cancer patients receiving radiotherapy (RT) to the breast or chest wall. Standard echocardiography and SRI were performed before RT (baseline), immediately after RT (post-RT), and at 2 months follow-up (FUP) after RT. Regional strain (S) and strain rate (SR) values were obtained from all 18 left ventricular (LV) segments. Data were compared to the regional radiation dose. Results: A reduction in S was observed post-RT and at FUP in left-sided patients (S{sub post-RT}: -17.6 {+-} 1.5%, and S{sub FUP}: -17.4 {+-} 2.3%, vs. S{sub baseline}: -19.5 {+-} 2.1%, p < 0.001) but not in right-sided patients. Within the left-sided patient group, S and SR were significantly reduced after RT in apical LV segments (S{sub post-RT}: -15.3 {+-} 2.5%, and S{sub FUP}: -14.3 {+-} 3.7%, vs. S{sub baseline}: -19.3 {+-} 3.0%, p < 0.01; and SR{sub post-RT}: -1.06 {+-} 0.15 s {sup -1}, and SR{sub FUP}: -1.16 {+-} 0.28 s {sup -1}, vs. SR{sub baseline}: -1.29 {+-} 0.27s {sup -1}, p = 0.01), but not in mid- or basal segments. Furthermore, we observed that segments exposed to more than 3 Gy showed a significant decrease in S after RT (S{sub post-RT}: -16.1 {+-} 1.6%, and S{sub FUP}: -15.8 {+-} 3.4%, vs. S{sub baseline}: -18.9 {+-} 2.6%, p < 0.001). This could not be observed in segments receiving less than 3 Gy. Conclusions: SRI shows a dose-related regional decrease in myocardial function after RT. It might be a useful tool in the evaluation of modern RT techniques, with respect to cardiac toxicity.

  2. Myocardial Blood Flow Quantification for Evaluation of Coronary Artery Disease by Positron Emission Tomography, Cardiac Magnetic Resonance Imaging, and Computed Tomography

    PubMed Central

    Waller, Alfonso H.; Blankstein, Ron; Kwong, Raymond Y.; Di Carli, Marcelo F.

    2014-01-01

    The noninvasive detection of the presence and functional significance of coronary artery stenosis is important in the diagnosis, risk assessment, and management of patients with known or suspected coronary artery disease. Quantitative assessment of myocardial perfusion can provide an objective and reproducible estimate of myocardial ischemia and risk prediction. Positron emission tomography, cardiac magnetic resonance, and cardiac computed tomography perfusion are modalities capable of measuring myocardial blood flow and coronary flow reserve. In this review, we will discuss the technical aspects of quantitative myocardial perfusion imaging with positron emission tomography, cardiac magnetic resonance imaging and computed tomography, and its emerging clinical applications. PMID:24718671

  3. Early detection of cardiac dysfunction in the type 1 diabetic heart using speckle-tracking based strain imaging.

    PubMed

    Shepherd, Danielle L; Nichols, Cody E; Croston, Tara L; McLaughlin, Sarah L; Petrone, Ashley B; Lewis, Sara E; Thapa, Dharendra; Long, Dustin M; Dick, Gregory M; Hollander, John M

    2016-01-01

    Enhanced sensitivity in echocardiographic analyses may allow for early detection of changes in cardiac function beyond the detection limits of conventional echocardiographic analyses, particularly in a small animal model. The goal of this study was to compare conventional echocardiographic measurements and speckle-tracking based strain imaging analyses in a small animal model of type 1 diabetes mellitus. Conventional analyses revealed differences in ejection fraction, fractional shortening, cardiac output, and stroke volume in diabetic animals relative to controls at 6-weeks post-diabetic onset. In contrast, when assessing short- and long-axis speckle-tracking based strain analyses, diabetic mice showed changes in average systolic radial strain, radial strain rate, radial displacement, and radial velocity, as well as decreased circumferential and longitudinal strain rate, as early as 1-week post-diabetic onset and persisting throughout the diabetic study. Further, we performed regional analyses for the LV and found that the free wall region was affected in both the short- and long-axis when assessing radial dimension parameters. These changes began 1-week post-diabetic onset and remained throughout the progression of the disease. These findings demonstrate the use of speckle-tracking based strain as an approach to elucidate cardiac dysfunction from a global perspective, identifying left ventricular cardiac regions affected during the progression of type 1 diabetes mellitus earlier than contractile changes detected by conventional echocardiographic measurements.

  4. Hybrid algorithm for three-dimensional flame chemiluminescence tomography based on imaging overexposure compensation.

    PubMed

    Jin, Ying; Song, Yang; Qu, Xiangju; Li, Zhenhua; Ji, Yunjing; He, Anzhi

    2016-08-01

    Flame tomography of chemiluminescence is a necessary combustion diagnostic technique that provides instantaneous 3D information on flame structure and excited species concentrations. During combustion diagnostics, imaging overexposure always causes missing information, which obviously decreases the accuracy in further reconstructions. In order to compensate imaging overexposure, a hybrid algorithm combining weight correction and Tikhonov's regularization is proposed in this paper. The intensity of the overexposure region can be estimated via the accumulation of weight coefficients. Meanwhile, Tikhonov's regularization is utilized to ameliorate the quality of reconstruction. The numerical simulation quantitatively evaluates the performance of the hybrid algorithm. Additionally, an experiment system consisting of 12 cameras was established to reconstruct the 3D combustion structure of axisymmetric flame with different exposure time settings. This work further investigates dynamic nonaxisymmetric propane diffusion flame. The obtained results show that the hybrid algorithm can effectively reveal the flame structure less influenced by imaging overexposure and achieve better results.

  5. Inorganic-Organic Hybrid Nanomaterials for Therapeutic and Diagnostic Imaging Applications

    PubMed Central

    Vivero-Escoto, Juan L.; Huang, Yu-Tzu

    2011-01-01

    Nanotechnology offers outstanding potential for future biomedical applications. In particular, due to their unique characteristics, hybrid nanomaterials have recently been investigated as promising platforms for imaging and therapeutic applications. This class of nanoparticles can not only retain valuable features of both inorganic and organic moieties, but also provides the ability to systematically modify the properties of the hybrid material through the combination of functional elements. Moreover, the conjugation of targeting moieties on the surface of these nanomaterials gives them specific targeted imaging and therapeutic properties. In this review, we summarize the recent reports in the synthesis of hybrid nanomaterials and their applications in biomedical areas. Their applications as imaging and therapeutic agents in vivo will be highlighted. PMID:21747714

  6. Hybrid algorithm for three-dimensional flame chemiluminescence tomography based on imaging overexposure compensation.

    PubMed

    Jin, Ying; Song, Yang; Qu, Xiangju; Li, Zhenhua; Ji, Yunjing; He, Anzhi

    2016-08-01

    Flame tomography of chemiluminescence is a necessary combustion diagnostic technique that provides instantaneous 3D information on flame structure and excited species concentrations. During combustion diagnostics, imaging overexposure always causes missing information, which obviously decreases the accuracy in further reconstructions. In order to compensate imaging overexposure, a hybrid algorithm combining weight correction and Tikhonov's regularization is proposed in this paper. The intensity of the overexposure region can be estimated via the accumulation of weight coefficients. Meanwhile, Tikhonov's regularization is utilized to ameliorate the quality of reconstruction. The numerical simulation quantitatively evaluates the performance of the hybrid algorithm. Additionally, an experiment system consisting of 12 cameras was established to reconstruct the 3D combustion structure of axisymmetric flame with different exposure time settings. This work further investigates dynamic nonaxisymmetric propane diffusion flame. The obtained results show that the hybrid algorithm can effectively reveal the flame structure less influenced by imaging overexposure and achieve better results. PMID:27505371

  7. Probability-based diagnostic imaging using hybrid features extracted from ultrasonic Lamb wave signals

    NASA Astrophysics Data System (ADS)

    Zhou, Chao; Su, Zhongqing; Cheng, Li

    2011-12-01

    The imaging technique based on guided waves has been a research focus in the field of damage detection over the years, aimed at intuitively highlighting structural damage in two- or three-dimensional images. The accuracy and efficiency of this technique substantially rely on the means of defining the field values at image pixels. In this study, a novel probability-based diagnostic imaging (PDI) approach was developed. Hybrid signal features (including temporal information, intensity of signal energy and signal correlation) were extracted from ultrasonic Lamb wave signals and integrated to retrofit the traditional way of defining field values. To acquire hybrid signal features, an active sensor network in line with pulse-echo and pitch-catch configurations was designed, supplemented with a novel concept of 'virtual sensing'. A hybrid image fusion scheme was developed to enhance the tolerance of the approach to measurement noise/uncertainties and erroneous perceptions from individual sensors. As applications, the approach was employed to identify representative damage scenarios including L-shape through-thickness crack (orientation-specific damage), polygonal damage (multi-edge damage) and multi-damage in structural plates. Results have corroborated that the developed PDI approach based on the use of hybrid signal features is capable of visualizing structural damage quantitatively, regardless of damage shape and number, by highlighting its individual edges in an easily interpretable binary image.

  8. Cardiovascular magnetic resonance in pregnancy: Insights from the cardiac hemodynamic imaging and remodeling in pregnancy (CHIRP) study

    PubMed Central

    2014-01-01

    Background Cardiovascular disease in pregnancy is the leading cause of maternal mortality in North America. Although transthoracic echocardiography (TTE) is the most widely used imaging modality for the assessment of cardiovascular function during pregnancy, little is known on the role of cardiovascular magnetic resonance (CMR). The objective of the Cardiac Hemodynamic Imaging and Remodeling in Pregnancy (CHIRP) study was to compare TTE and CMR in the non-invasive assessment of maternal cardiac remodeling during the peripartum period. Methods Between 2010–2012, healthy pregnant women aged 18 to 35 years were prospectively enrolled. All women underwent TTE and CMR during the third trimester and at least 3 months postpartum (surrogate for non-pregnant state). Results The study population included a total of 34 women (mean age 29 ± 3 years). During the third trimester, TTE and CMR demonstrated an increase in left ventricular end-diastolic volume from 95 ± 11 mL to 115 ± 14 mL and 98 ± 6 mL to 125 ± 5 mL, respectively (p < 0.05). By TTE and CMR, there was also an increase in left ventricular (LV) mass during pregnancy from 111 ± 10 g to 163 ± 11 g and 121 ± 5 g to 179 ± 5 g, respectively (p < 0.05). Although there was good correlation between both imaging modalities for LV mass, stroke volume, and cardiac output, the values were consistently underestimated by TTE. Conclusion This CMR study provides reference values for cardiac indices during normal pregnancy and the postpartum state. PMID:24387349

  9. An investigation of flat panel equipment variables on image quality with a dedicated cardiac phantom

    NASA Astrophysics Data System (ADS)

    Dragusin, O.; Bosmans, H.; Pappas, C.; Desmet, W.

    2008-09-01

    Image quality (IQ) evaluation plays a key role in the process of optimization of new x-ray systems. Ideally, this process should be supported by real clinical images, but ethical issues and differences in anatomy and pathology of patients make it impossible. Phantom studies might overcome these issues. This paper presents the IQ evaluation of 30 cineangiographic films acquired with a cardiac flat panel system. The phantom used simulates the anatomy of the heart and allows the circulation of contrast agent boluses through coronary arteries. Variables investigated with influence on IQ and radiation dose are: tube potential, detector dose, added Copper filters, dynamic density optimization (DDO) and viewing angle. The IQ evaluation consisted of scoring 4 simulated calcified lesions located on different coronary artery segments in terms of degree of visualization. Eight cardiologists rated the lesions using a five-point scale ((1) lesion not visible to (5) very good visibility). Radiation doses associated to the angiograms are expressed in terms of incident air kerma (IAK) and effective dose that has been calculated with PCXMX software (STUK, Finland) from the exposure settings assuming a standard sized patient of 70 Kg. Mean IQ scores ranged from 1.68 to 4.88. The highest IQ scores were obtained for the angiograms acquired with tube potential 80 kVp, no added Cu filters, DDO 60%, RAO and LAO views and the highest entrance detector dose that has been used in the present study, namely 0.17 μGy/im. Radiation doses (IAK ~40 mGy and effective dose of 1 mSv) were estimated for angiograms acquired at 15 frames s-1, detector field-of-view 20 cm, and a length of 5 s. The following parameters improved the IQ factor significantly: a change in tube potential from 96 to 80 kVp, detector dose from 0.10 μGy/im to 0.17 μGy/im, the absence of Copper filtration. DDO variable which is a post-processing parameter should be carefully evaluated because it alters the quality of the

  10. Hybrid-modality ocular imaging using a clinical ultrasound system and nanosecond pulsed laser

    PubMed Central

    Lim, Hoong-Ta; Matham, Murukeshan Vadakke

    2015-01-01

    Abstract. Hybrid optical modality imaging is a special type of multimodality imaging significantly used in the recent past in order to harness the strengths of different imaging methods as well as to furnish complementary information beyond that provided by any individual method. We present a hybrid-modality imaging system based on a commercial clinical ultrasound imaging (USI) system using a linear array ultrasound transducer (UST) and a tunable nanosecond pulsed laser as the source. The integrated system uses photoacoustic imaging (PAI) and USI for ocular imaging to provide the complementary absorption and structural information of the eye. In this system, B-mode images from PAI and USI are acquired at 10 Hz and about 40 Hz, respectively. A linear array UST makes the system much faster compared to other ocular imaging systems using a single-element UST to form B-mode images. The results show that the proposed instrumentation is able to incorporate PAI and USI in a single setup. The feasibility and efficiency of this developed probe system was illustrated by using enucleated pig eyes as test samples. It was demonstrated that PAI could successfully capture photoacoustic signals from the iris, anterior lens surface, and posterior pole, while USI could accomplish the mapping of the eye to reveal the structures like the cornea, anterior chamber, lens, iris, and posterior pole. This system and the proposed methodology are expected to enable ocular disease diagnostic applications and can be used as a preclinical imaging system. PMID:26835487

  11. Sci—Thur PM: Imaging — 01: Position-sensitive noise characteristics in multi-pinhole cardiac SPECT imaging

    SciTech Connect

    Cuddy-Walsh, SG; Wells, RG

    2014-08-15

    Myocardial perfusion imaging (MPI) with Single Photon Emission Computed Tomography (SPECT) is invaluable in the diagnosis and management of heart disease. It provides essential information on myocardial blood flow and ischemia. Multi-pinhole dedicated cardiac-SPECT cameras offer improved count sensitivity, and spatial and energy resolutions over parallel-hole camera designs however variable sensitivity across the field-of-view (FOV) can lead to position-dependent noise variations. Since MPI evaluates differences in the signal-to-noise ratio, noise variations in the camera could significantly impact the sensitivity of the test for ischemia. We evaluated the noise characteristics of GE Healthcare's Discovery NM530c camera with a goal of optimizing the accuracy of our patient assessment and thereby improving outcomes. Theoretical sensitivity maps of the camera FOV, including attenuation effects, were estimated analytically based on the distance and angle between the spatial position of a given voxel and each pinhole. The standard deviation in counts, σ was inferred for each voxel position from the square root of the sensitivity mapped at that position. Noise was measured experimentally from repeated (N=16) acquisitions of a uniform spherical Tc-99m-water phantom. The mean (μ) and standard deviation (σ) were calculated for each voxel position in the reconstructed FOV. Noise increased ∼2.1× across a 12 cm sphere. A correlation of 0.53 is seen when experimental noise is compared with theory suggesting that ∼53% of the noise is attributed to the combined effects of attenuation and the multi-pinhole geometry. Further investigations are warranted to determine the clinical impact of the position-dependent noise variation.

  12. Wideband Arrhythmia-Insensitive-Rapid (AIR) Pulse Sequence for Cardiac T1 mapping without Image Artifacts induced by ICD

    PubMed Central

    Hong, KyungPyo; Jeong, Eun-Kee; Wall, T. Scott; Drakos, Stavros G.; Kim, Daniel

    2015-01-01

    Purpose To develop and evaluate a wideband arrhythmia-insensitive-rapid (AIR) pulse sequence for cardiac T1 mapping without image artifacts induced by implantable-cardioverter-defibrillator (ICD). Methods We developed a wideband AIR pulse sequence by incorporating a saturation pulse with wide frequency bandwidth (8.9 kHz), in order to achieve uniform T1 weighting in the heart with ICD. We tested the performance of original and “wideband” AIR cardiac T1 mapping pulse sequences in phantom and human experiments at 1.5T. Results In 5 phantoms representing native myocardium and blood and post-contrast blood/tissue T1 values, compared with the control T1 values measured with an inversion-recovery pulse sequence without ICD, T1 values measured with original AIR with ICD were considerably lower (absolute percent error >29%), whereas T1 values measured with wideband AIR with ICD were similar (absolute percent error <5%). Similarly, in 11 human subjects, compared with the control T1 values measured with original AIR without ICD, T1 measured with original AIR with ICD was significantly lower (absolute percent error >10.1%), whereas T1 measured with wideband AIR with ICD was similar (absolute percent error <2.0%). Conclusion This study demonstrates the feasibility of a wideband pulse sequence for cardiac T1 mapping without significant image artifacts induced by ICD. PMID:25975192

  13. Cardiac imaging with multi-sector data acquisition in volumetric CT: variation of effective temporal resolution and its potential clinical consequences

    NASA Astrophysics Data System (ADS)

    Tang, Xiangyang; Hsieh, Jiang; Taha, Basel H.; Vass, Melissa L.; Seamans, John L.; Okerlund, Darin R.

    2009-02-01

    With increasing longitudinal detector dimension available in diagnostic volumetric CT, step-and-shoot scan is becoming popular for cardiac imaging. In comparison to helical scan, step-and-shoot scan decouples patient table movement from cardiac gating/triggering, which facilitates the cardiac imaging via multi-sector data acquisition, as well as the administration of inter-cycle heart beat variation (arrhythmia) and radiation dose efficiency. Ideally, a multi-sector data acquisition can improve temporal resolution at a factor the same as the number of sectors (best scenario). In reality, however, the effective temporal resolution is jointly determined by gantry rotation speed and patient heart beat rate, which may significantly lower than the ideal or no improvement (worst scenario). Hence, it is clinically relevant to investigate the behavior of effective temporal resolution in cardiac imaging with multi-sector data acquisition. In this study, a 5-second cine scan of a porcine heart, which cascades 6 porcine cardiac cycles, is acquired. In addition to theoretical analysis and motion phantom study, the clinical consequences due to the effective temporal resolution variation are evaluated qualitative or quantitatively. By employing a 2-sector image reconstruction strategy, a total of 15 (the permutation of P(6, 2)) cases between the best and worst scenarios are studied, providing informative guidance for the design and optimization of CT cardiac imaging in volumetric CT with multi-sector data acquisition.

  14. Unrecognized Myocardial Infarction Assessed by Cardiac Magnetic Resonance Imaging – Prognostic Implications

    PubMed Central

    Ahlström, Håkan; Bjerner, Tomas; Duvernoy, Olov; Eggers, Kai M.; Fröbert, Ole; Hadziosmanovic, Nermin

    2016-01-01

    Background Clinically unrecognized myocardial infarctions (UMI) are not uncommon and may be associated with adverse outcome. The aims of this study were to determine the prognostic implication of UMI in patients with stable suspected coronary artery disease (CAD) and to investigate the associations of UMI with the presence of CAD. Methods and Findings In total 235 patients late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR) imaging and coronary angiography were performed. For each patient with UMI, the stenosis grade of the coronary branch supplying the infarcted area was determined. UMIs were present in 25% of the patients and 67% of the UMIs were located in an area supplied by a coronary artery with a stenosis grade ≥70%. In an age- and gender-adjusted model, UMI independently predicted the primary endpoint (composite of death, myocardial infarction, resuscitated cardiac arrest, hospitalization for unstable angina pectoris or heart failure within 2 years of follow-up) with an odds ratio of 2.9; 95% confidence interval 1.1–7.9. However, this association was abrogated after adjustment for age and presence of significant coronary disease. There was no difference in the primary endpoint rates between UMI patients with or without a significant stenosis in the corresponding coronary artery. Conclusions The presence of UMI was associated with a threefold increased risk of adverse events during follow up. However, the difference was no longer statistically significant after adjustments for age and severity of CAD. Thus, the results do not support that patients with suspicion of CAD should be routinely investigated by LGE-CMR for UMI. However, coronary angiography should be considered in patients with UMI detected by LGE-CMR. Trial Registration ClinicalTrials.gov NTC01257282 PMID:26885831

  15. Can emergency physicians reliably interpret cardiac CT images? A prospective observational study

    PubMed Central

    Kwon, Joon-myoung; Kim, Joonghee; Kim, Kyuseok; Kim, Taeyun; Jo, You Hwan; Lee, Jin Hee; Lee, Jae Hyuk; Kim, Yu Jin; Jung, Jae Yun

    2015-01-01

    Objective Cardiac computed tomography (CCT) is useful for evaluation of acute chest pain in the emergency department (ED). Though the test needs proper interpretation by someone with expertise in cardiovascular imaging, the critical nature of the information the test provides frequently lead emergency physicians (EPs) to act on their own interpretation. We performed this study to assess how often EPs’ interpretations are in agreement with radiologists’. Methods This study is a prospective observational study. The target population was patients assessed with CCT for acute chest pain or discomfort. EPs with at least one year CCT experience underwent a one-hour training session before study participation. The most significant lesion, if any, in each arterial segment was assessed for coronary stenosis and plaque calcification. The agreement between EPs’ and radiologists’ interpretation was assessed with Cohen’s kappa and Gwet’s AC1. Results One hundred and three patients were enrolled and 412 segments were analyzed. Stenosis grading was identical in 363 segments (88.1%) and the interrater agreement was good (kappa=0.6439, AC1=0.8810). Similarly, the plaque calcification grading was identical in 354 segments (86.6%) and the kappa and AC1 values were 0.5660 and 0.8501, respectively. EPs classified 6 of the 17 arterial segments with significant stenosis reported by radiologists as non-significant stenosis (n=5) or clear (n=2), all of which were proved to be significant by following subsequent invasive coronary angiography. Conclusion There was substantial discordance of CCT interpretation between EPs and radiologists. For now, EPs need more education prior to independent CCT reading.

  16. Defining myocardial tissue abnormalities in end-stage renal failure with cardiac magnetic resonance imaging using native T1 mapping.

    PubMed

    Rutherford, Elaine; Talle, Mohammed A; Mangion, Kenneth; Bell, Elizabeth; Rauhalammi, Samuli M; Roditi, Giles; McComb, Christie; Radjenovic, Aleksandra; Welsh, Paul; Woodward, Rosemary; Struthers, Allan D; Jardine, Alan G; Patel, Rajan K; Berry, Colin; Mark, Patrick B

    2016-10-01

    Noninvasive quantification of myocardial fibrosis in end-stage renal disease is challenging. Gadolinium contrast agents previously used for cardiac magnetic resonance imaging (MRI) are contraindicated because of an association with nephrogenic systemic fibrosis. In other populations, increased myocardial native T1 times on cardiac MRI have been shown to be a surrogate marker of myocardial fibrosis. We applied this method to 33 incident hemodialysis patients and 28 age- and sex-matched healthy volunteers who underwent MRI at 3.0T. Native T1 relaxation times and feature tracking-derived global longitudinal strain as potential markers of fibrosis were compared and associated with cardiac biomarkers. Left ventricular mass indices were higher in the hemodialysis than the control group. Global, Septal and midseptal T1 times were all significantly higher in the hemodialysis group (global T1 hemodialysis 1171 ± 27 ms vs. 1154 ± 32 ms; septal T1 hemodialysis 1184 ± 29 ms vs. 1163 ± 30 ms; and midseptal T1 hemodialysis 1184 ± 34 ms vs. 1161 ± 29 ms). In the hemodialysis group, T1 times correlated with left ventricular mass indices. Septal T1 times correlated with troponin and electrocardiogram-corrected QT interval. The peak global longitudinal strain was significantly reduced in the hemodialysis group (hemodialysis -17.7±5.3% vs. -21.8±6.2%). For hemodialysis patients, the peak global longitudinal strain significantly correlated with left ventricular mass indices (R = 0.426), and a trend was seen for correlation with galectin-3, a biomarker of cardiac fibrosis. Thus, cardiac tissue properties of hemodialysis patients consistent with myocardial fibrosis can be determined noninvasively and associated with multiple structural and functional abnormalities.

  17. Global Hybrid HRSC+OMEGA Image Mosaics of Mars

    NASA Astrophysics Data System (ADS)

    McGuire, P. C.; Walter, S. H. G.; van Gasselt, S.; Dunke, A.; Dunker, T.; Gross, C.; Michael, G.; Wendt, L.; Audouard, J.; Ody, A.; Poulet, F.

    2014-04-01

    The High Resolution Stereo Camera (HRSC) on the Mars Express (MEx) orbiter has acquired 3640 images (with 'preliminary level 4' processing as described in [1]) of the Martian surface since arriving in orbit in 2003, covering over 90% of the planet [2]. At resolutions that can reach 10 meters/pixel, these MEx/HRSC images [3-4] are constructed in a pushbroom manner from 9 different CCD line sensors, including a panchromatic nadir-looking (Pan) channel, 4 color channels (R, G, B, IR), and 4 other panchromatic channels for stereo imaging or photometric imaging. In [5], we discussed our approach towards automatically mosaicking hundreds of the MEx/HRSC Pan or RGB images together. Herein, we present our latest results using this approach (Fig. 1; PDF is zoomable). Currently, our best results consist of adding a high-pass-filtered version of the HRSC mosaic to a low-pass-filtered version of the MEx/OMEGA [6] global mosaic.

  18. Application of Micro-Computed Tomography with Iodine Staining to Cardiac Imaging, Segmentation and Computational Model Development

    PubMed Central

    Aslanidi, OV; Nikolaidou, T; Zhao, J; Smaill, BH; Gilbert, SH; Holden, AV; Lowe, T; Withers, PJ; Jarvis, JC; Stephenson, RS; Hart, G; Hancox, JC; Boyett, MR; Zhang, H

    2012-01-01

    Micro-computed tomography (micro-CT) has been widely used to generate high-resolution 3D tissue images from small animals non-destructively, especially for mineralized skeletal tissues. However, its application to the analysis of soft cardiovascular tissues has been limited by poor inter-tissue contrast. Recent ex vivo studies have shown that contrast between muscular and connective tissue in micro-CT images can be enhanced by staining with iodine. In the present study, we apply this novel technique for imaging of cardiovascular structures in canine hearts. We optimize the method to obtain high resolution X-ray micro-CT images of the canine atria and its distinctive regions - including the Bachmann’s bundle, atrioventricular node, pulmonary arteries and veins - with clear inter-tissue contrast. The imaging results are used to reconstruct and segment the detailed 3D geometry of the atria. Structure tensor analysis shows that the arrangement of atrial fibres can also be characterised using the enhanced micro-CT images, as iodine preferentially accumulates within the muscular fibres rather than in connective tissues. This novel technique can be particularly useful in non-destructive imaging of 3D cardiac architectures from large animals and humans, due to the combination of relatively high speed (~1 hour/scan of a large canine heart) and high voxel resolution (36 μm) provided. In summary, contrast micro-CT facilitates fast and non-destructive imaging and segmenting of detailed 3D cardiovascular geometries, as well as measuring fibre orientation, which are crucial in constructing biophysically detailed computational cardiac models. PMID:22829390

  19. MRI Mode Programming for Safe Magnetic Resonance Imaging in Patients With a Magnetic Resonance Conditional Cardiac Device.

    PubMed

    Nakai, Toshiko; Kurokawa, Sayaka; Ikeya, Yukitoshi; Iso, Kazuki; Takahashi, Keiko; Sasaki, Naoko; Ashino, Sonoko; Okubo, Kimie; Okumura, Yasuo; Kunimoto, Satoshi; Watanabe, Ichiro; Hirayama, Atsushi

    2016-01-01

    Although diagnostically indispensable, magnetic resonance imaging (MRI) has been, until recently, contraindicated in patients with an implantable cardiac device. MR conditional cardiac devices are now widely used, but the mode programming needed for safe MRI has yet to be established. We reviewed the details of 41 MRI examinations of patients with a MR conditional device. There were no associated adverse events. However, in 3 cases, paced beats competed with the patient's own beats during the MRI examination. We describe 2 of the 3 specific cases because they illustrate these potentially risky situations: a case in which the intrinsic heart rate increased and another in which atrial fibrillation occurred. Safe MRI in patients with an MR conditional device necessitates detailed MRI mode programming. The MRI pacing mode should be carefully and individually selected.

  20. The role and regulation of cardiac angiotensin-converting enzyme for noninvasive molecular imaging in heart failure.

    PubMed

    Aras, Omer; Messina, Steven A; Shirani, Jamshid; Eckelman, William C; Dilsizian, Vasken

    2007-04-01

    Congestive heart failure is a pathologic condition characterized by progressive decrease in left ventricular contractility and consequent decline of cardiac output. There is convincing clinical and experimental evidence that the renin-angiotensin system (RAS) and its primary effector peptide, angiotensin II, are linked to the pathophysiology of interstitial fibrosis, cardiac remodeling, and heart failure. In addition to the traditional endocrine or circulating RAS, an active tissue RAS has been characterized. Tissue angiotensin-converting enzyme and locally synthesized angiotensin II, for example, by chymase, exert local trophic effects that modulate gene expression, which regulates growth and proliferation in both myocytes and nonmyocytes. The existence of the tissue RAS offers an opportunity for targeted imaging, which may be of considerable value for guiding medical therapy. PMID:17430683

  1. Prospective-gated cardiac micro-CT imaging of free-breathing mice using carbon nanotube field emission x-ray

    SciTech Connect

    Cao Guohua; Burk, Laurel M.; Lee, Yueh Z.; Calderon-Colon, Xiomara; Sultana, Shabana; Lu Jianping; Zhou, Otto

    2010-10-15

    Purpose: Carbon nanotube (CNT) based field emission x-ray source technology has recently been investigated for diagnostic imaging applications because of its attractive characteristics including electronic programmability, fast switching, distributed source, and multiplexing. The purpose of this article is to demonstrate the potential of this technology for high-resolution prospective-gated cardiac micro-CT imaging. Methods: A dynamic cone-beam micro-CT scanner was constructed using a rotating gantry, a stationary mouse bed, a flat-panel detector, and a sealed CNT based microfocus x-ray source. The compact single-beam CNT x-ray source was operated at 50 KVp and 2 mA anode current with 100 {mu}mx100 {mu}m effective focal spot size. Using an intravenously administered iodinated blood-pool contrast agent, prospective cardiac and respiratory-gated micro-CT images of beating mouse hearts were obtained from ten anesthetized free-breathing mice in their natural position. Four-dimensional cardiac images were also obtained by gating the image acquisition to different phases in the cardiac cycle. Results: High-resolution CT images of beating mouse hearts were obtained at 15 ms temporal resolution and 6.2 lp/mm spatial resolution at 10% of system MTF. The images were reconstructed at 76 {mu}m isotropic voxel size. The data acquisition time for two cardiac phases was 44{+-}9 min. The CT values observed within the ventricles and the ventricle wall were 455{+-}49 and 120{+-}48 HU, respectively. The entrance dose for the acquisition of a single phase of the cardiac cycle was 0.10 Gy. Conclusions: A high-resolution dynamic micro-CT scanner was developed from a compact CNT microfocus x-ray source and its feasibility for prospective-gated cardiac micro-CT imaging of free-breathing mice under their natural position was demonstrated.

  2. Acquisition and automated 3-D segmentation of respiratory/cardiac-gated PET transmission images

    SciTech Connect

    Reutter, B.W.; Klein, G.J.; Brennan, K.M.; Huesman, R.H. |

    1996-12-31

    To evaluate the impact of respiratory motion on attenuation correction of cardiac PET data, we acquired and automatically segmented gated transmission data for a dog breathing on its own under gas anesthesia. Data were acquired for 20 min on a CTI/Siemens ECAT EXACT HR (47-slice) scanner configured for 12 gates in a static study, Two respiratory gates were obtained using data from a pneumatic bellows placed around the dog`s chest, in conjunction with 6 cardiac gates from standard EKG gating. Both signals were directed to a LabVIEW-controlled Macintosh, which translated them into one of 12 gate addresses. The respiratory gating threshold was placed near end-expiration to acquire 6 cardiac-gated datasets at end-expiration and 6 cardiac-gated datasets during breaths. Breaths occurred about once every 10 sec and lasted about 1-1.5 sec. For each respiratory gate, data were summed over cardiac gates and torso and lung surfaces were segmented automatically using a differential 3-D edge detection algorithm. Three-dimensional visualizations showed that lung surfaces adjacent to the heart translated 9 mm inferiorly during breaths. Our results suggest that respiration-compensated attenuation correction is feasible with a modest amount of gated transmission data and is necessary for accurate quantitation of high-resolution gated cardiac PET data.

  3. Risk stratification of patients with chronic heart failure using cardiac iodine‐123 metaiodobenzylguanidine imaging: incremental prognostic value over right ventricular ejection fraction

    PubMed Central

    Yamada, Takahisa; Morita, Takashi; Furukawa, Yoshio; Iwasaki, Yusuke; Kawasaki, Masato; Kikuchi, Atsushi; Kondo, Takumi; Kawai, Tsutomu; Takahashi, Satoshi; Ishimi, Masashi; Hakui, Hideyuki; Ozaki, Tatsuhisa; Sato, Yoshihiro; Seo, Masahiro; Sakata, Yasushi; Fukunami, Masatake

    2015-01-01

    Abstract Aims Right ventricular (RV) systolic dysfunction has been shown to be an independent predictor of clinical outcome in patients with chronic heart failure (CHF), and cardiac metaiodobenzylguanidine (MIBG) imaging also provides prognostic information. We aimed to evaluate the long‐term predictive value of combining RV systolic dysfunction and abnormal findings of cardiac MIBG imaging on outcome in CHF patients. Methods and results We enrolled 63 CHF outpatients with left ventricular ejection fraction (EF) <40% in a prospective cohort study. At entry, RVEF was measured by radionuclide angiography. Furthermore, cardiac MIBG imaging was performed, and the cardiac MIBG washout rate (WR) was calculated. Reduced RVEF was defined as ≤37%, and abnormal WR was defined as >27%. The study endpoint was unplanned hospitalization for worsening heart failure (WHF) and cardiac death. During a follow‐up period of 8.9 ± 4.3 years, 19 of 63 patients had unplanned hospitalization for WHF, and 19 of 63 patients had cardiac death. In multivariate analysis, both WR and RVEF were independent predictors of unplanned WHF hospitalization, while WR was also an independent predictor of cardiac death. A risk‐stratification model based on independent predictors of unplanned WHF hospitalization separated the patients into those with low (absence of the predictors), intermediate (one of the predictors), and high (two or more of the predictors) risk of unplanned WHF hospitalization (P < 0.0001) or cardiac death (P = 0.0113). Conclusions Cardiac MIBG imaging provides incremental value when it is used along with RV systolic dysfunction to predict clinical outcome in patients with CHF.

  4. Towards integration of PET/MR hybrid imaging into radiation therapy treatment planning

    SciTech Connect

    Paulus, Daniel H.; Thorwath, Daniela; Schmidt, Holger; Quick, Harald H.

    2014-07-15

    Purpose: Multimodality imaging has become an important adjunct of state-of-the-art radiation therapy (RT) treatment planning. Recently, simultaneous PET/MR hybrid imaging has become clinically available and may also contribute to target volume delineation and biological individualization in RT planning. For integration of PET/MR hybrid imaging into RT treatment planning, compatible dedicated RT devices are required for accurate patient positioning. In this study, prototype RT positioning devices intended for PET/MR hybrid imaging are introduced and tested toward PET/MR compatibility and image quality. Methods: A prototype flat RT table overlay and two radiofrequency (RF) coil holders that each fix one flexible body matrix RF coil for RT head/neck imaging have been evaluated within this study. MR image quality with the RT head setup was compared to the actual PET/MR setup with a dedicated head RF coil. PET photon attenuation and CT-based attenuation correction (AC) of the hardware components has been quantitatively evaluated by phantom scans. Clinical application of the new RT setup in PET/MR imaging was evaluated in anin vivo study. Results: The RT table overlay and RF coil holders are fully PET/MR compatible. MR phantom and volunteer imaging with the RT head setup revealed high image quality, comparable to images acquired with the dedicated PET/MR head RF coil, albeit with 25% reduced SNR. Repositioning accuracy of the RF coil holders was below 1 mm. PET photon attenuation of the RT table overlay was calculated to be 3.8% and 13.8% for the RF coil holders. With CT-based AC of the devices, the underestimation error was reduced to 0.6% and 0.8%, respectively. Comparable results were found within the patient study. Conclusions: The newly designed RT devices for hybrid PET/MR imaging are PET and MR compatible. The mechanically rigid design and the reproducible positioning allow for straightforward CT-based AC. The systematic evaluation within this study provides the

  5. Hybrid gold-gadolinium nanoclusters for tumor-targeted NIRF/CT/MRI triple-modal imaging in vivo

    NASA Astrophysics Data System (ADS)

    Hu, De-Hong; Sheng, Zong-Hai; Zhang, Peng-Fei; Yang, Da-Zhi; Liu, Shu-Hui; Gong, Ping; Gao, Du-Yang; Fang, Sheng-Tao; Ma, Yi-Fan; Cai, Lin-Tao

    2013-01-01

    Multimodal imaging is highly desirable for accurate diagnosis because it can provide complementary information from each imaging modality. In this study, we prepared hybrid gold-gadolinium nanoclusters (NCs), which are ultrasmall, stable, biocompatible, and suitable for triple-modal NIRF/CT/MRI imaging. Upon intravenously injected, the hybrid NCs are effectively accumulated in tumor tissues and quickly clear by renal excretion, indicating their capacity of tumor targeting and low body residues. Notably, the ultrasmall hybrid NCs would penetrate into the solid tumor for capturing its heterostructure and do not induce potential toxicity in vivo. Hence, the well-defined hybrid gold-gadolinium NCs provide a versatile nanoprobe for cancer targeted imaging and diagnosis in vivo.Multimodal imaging is highly desirable for accurate diagnosis because it can provide complementary information from each imaging modality. In this study, we prepared hybrid gold-gadolinium nanoclusters (NCs), which are ultrasmall, stable, biocompatible, and suitable for triple-modal NIRF/CT/MRI imaging. Upon intravenously injected, the hybrid NCs are effectively accumulated in tumor tissues and quickly clear by renal excretion, indicating their capacity of tumor targeting and low body residues. Notably, the ultrasmall hybrid NCs would penetrate into the solid tumor for capturing its heterostructure and do not induce potential toxicity in vivo. Hence, the well-defined hybrid gold-gadolinium NCs provide a versatile nanoprobe for cancer targeted imaging and diagnosis in vivo. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr33543c

  6. Multiobjective Image Color Quantization Algorithm Based on Self-Adaptive Hybrid Differential Evolution

    PubMed Central

    Xia, Xuewen

    2016-01-01

    In recent years, some researchers considered image color quantization as a single-objective problem and applied heuristic algorithms to solve it. This paper establishes a multiobjective image color quantization model with intracluster distance and intercluster separation as its objectives. Inspired by a multipopulation idea, a multiobjective image color quantization algorithm based on self-adaptive hybrid differential evolution (MoDE-CIQ) is then proposed to solve this model. Two numerical experiments on four common test images are conducted to analyze the effectiveness and competitiveness of the multiobjective model and the proposed algorithm. PMID:27738423

  7. Hybrid Online Mobile Laser Scanner Calibration Through Image Alignment by Mutual Information

    NASA Astrophysics Data System (ADS)

    Miled, Mourad; Soheilian, Bahman; Habets, Emmanuel; Vallet, Bruno

    2016-06-01

    This paper proposes an hybrid online calibration method for a laser scanner mounted on a mobile platform also equipped with an imaging system. The method relies on finding the calibration parameters that best align the acquired points cloud to the images. The quality of this intermodal alignment is measured by Mutual information between image luminance and points reflectance. The main advantage and motivation is ensuring pixel accurate alignment of images and point clouds acquired simultaneously, but it is also much more flexible than traditional laser calibration methods.

  8. Development of a Hybrid Magnetic Resonance and Ultrasound Imaging System

    PubMed Central

    Sherwood, Victoria; Rivens, Ian; Collins, David J.; Leach, Martin O.; ter Haar, Gail R.

    2014-01-01

    A system which allows magnetic resonance (MR) and ultrasound (US) image data to be acquired simultaneously has been developed. B-mode and Doppler US were performed inside the bore of a clinical 1.5 T MRI scanner using a clinical 1–4 MHz US transducer with an 8-metre cable. Susceptibility artefacts and RF noise were introduced into MR images by the US imaging system. RF noise was minimised by using aluminium foil to shield the transducer. A study of MR and B-mode US image signal-to-noise ratio (SNR) as a function of transducer-phantom separation was performed using a gel phantom. This revealed that a 4 cm separation between the phantom surface and the transducer was sufficient to minimise the effect of the susceptibility artefact in MR images. MR-US imaging was demonstrated in vivo with the aid of a 2 mm VeroWhite 3D-printed spherical target placed over the thigh muscle of a rat. The target allowed single-point registration of MR and US images in the axial plane to be performed. The system was subsequently demonstrated as a tool for the targeting and visualisation of high intensity focused ultrasound exposure in the rat thigh muscle. PMID:25177702

  9. Hybrid gadolinium oxide nanoparticles: multimodal contrast agents for in vivo imaging.

    PubMed

    Bridot, Jean-Luc; Faure, Anne-Charlotte; Laurent, Sophie; Rivière, Charlotte; Billotey, Claire; Hiba, Bassem; Janier, Marc; Josserand, Véronique; Coll, Jean-Luc; Elst, Luce Vander; Muller, Robert; Roux, Stéphane; Perriat, Pascal; Tillement, Olivier

    2007-04-25

    Luminescent hybrid nanoparticles with a paramagnetic Gd2O3 core were applied as contrast agents for both in vivo fluorescence and magnetic resonance imaging. These hybrid particles were obtained by encapsulating Gd2O3 cores within a polysiloxane shell which carries organic fluorophores and carboxylated PEG covalently tethered to the inorganic network. Longitudinal proton relaxivities of these particles are higher than the positive contrast agents like Gd-DOTA which are commonly used for clinical magnetic resonance imaging. Moreover these particles can be followed up by fluorescence imaging. This study revealed that these particles suited for dual modality imaging freely circulate in the blood vessels without undesirable accumulation in lungs and liver.

  10. 2D dose distribution images of a hybrid low field MRI-γ detector

    NASA Astrophysics Data System (ADS)

    Abril, A.; Agulles-Pedrós, L.

    2016-07-01

    The proposed hybrid system is a combination of a low field MRI and dosimetric gel as a γ detector. The readout system is based on the polymerization process induced by the gel radiation. A gel dose map is obtained which represents the functional part of hybrid image alongside with the anatomical MRI one. Both images should be taken while the patient with a radiopharmaceutical is located inside the MRI system with a gel detector matrix. A relevant aspect of this proposal is that the dosimetric gel has never been used to acquire medical images. The results presented show the interaction of the 99mTc source with the dosimetric gel simulated in Geant4. The purpose was to obtain the planar γ 2D-image. The different source configurations are studied to explore the ability of the gel as radiation detector through the following parameters; resolution, shape definition and radio-pharmaceutical concentration.

  11. A Voluntary Breath-Hold Treatment Technique for the Left Breast With Unfavorable Cardiac Anatomy Using Surface Imaging

    SciTech Connect

    Gierga, David P.; Turcotte, Julie C.; Sharp, Gregory C.; Sedlacek, Daniel E.; Cotter, Christopher R.; Taghian, Alphonse G.

    2012-12-01

    Purpose: Breath-hold (BH) treatments can be used to reduce cardiac dose for patients with left-sided breast cancer and unfavorable cardiac anatomy. A surface imaging technique was developed for accurate patient setup and reproducible real-time BH positioning. Methods and Materials: Three-dimensional surface images were obtained for 20 patients. Surface imaging was used to correct the daily setup for each patient. Initial setup data were recorded for 443 fractions and were analyzed to assess random and systematic errors. Real time monitoring was used to verify surface placement during BH. The radiation beam was not turned on if the BH position difference was greater than 5 mm. Real-time surface data were analyzed for 2398 BHs and 363 treatment fractions. The mean and maximum differences were calculated. The percentage of BHs greater than tolerance was calculated. Results: The mean shifts for initial patient setup were 2.0 mm, 1.2 mm, and 0.3 mm in the vertical, longitudinal, and lateral directions, respectively. The mean 3-dimensional vector shift was 7.8 mm. Random and systematic errors were less than 4 mm. Real-time surface monitoring data indicated that 22% of the BHs were outside the 5-mm tolerance (range, 7%-41%), and there was a correlation with breast volume. The mean difference between the treated and reference BH positions was 2 mm in each direction. For out-of-tolerance BHs, the average difference in the BH position was 6.3 mm, and the average maximum difference was 8.8 mm. Conclusions: Daily real-time surface imaging ensures accurate and reproducible positioning for BH treatment of left-sided breast cancer patients with unfavorable cardiac anatomy.

  12. Optimization of SPECT-CT Hybrid Imaging Using Iterative Image Reconstruction for Low-Dose CT: A Phantom Study

    PubMed Central

    Grosser, Oliver S.; Kupitz, Dennis; Ruf, Juri; Czuczwara, Damian; Steffen, Ingo G.; Furth, Christian; Thormann, Markus; Loewenthal, David; Ricke, Jens; Amthauer, Holger

    2015-01-01

    Background Hybrid imaging combines nuclear medicine imaging such as single photon emission computed tomography (SPECT) or positron emission tomography (PET) with computed tomography (CT). Through this hybrid design, scanned patients accumulate radiation exposure from both applications. Imaging modalities have been the subject of long-term optimization efforts, focusing on diagnostic applications. It was the aim of this study to investigate the influence of an iterative CT image reconstruction algorithm (ASIR) on the image quality of the low-dose CT