Showing papers on "Cardiac magnetic resonance imaging published in 2002"

Cardiac magnetic resonance imaging: a "one-stop-shop" evaluation of myocardial dysfunction.

Abstract: A faster and more precise method for determining hibernating myocardium remains the holy grail of noninvasive cardiac imaging. Nuclear or echocardiogram-based imaging techniques have been the key modalities for evaluating important markers of cardiac viability. Advances in hardware and software for

Fast phase contrast cardiac magnetic resonance imaging: Improved assessment and analysis of left ventricular wall motion

Abstract: Purpose To evaluate the use of CINE phase contrast magnetic resonance imaging (MRI) to assess and characterize left ventricular wall motion by two- or three-directional velocity vector fields that reflect the temporal evolution of myocardial velocities over the whole cardiac cycle. Material and Methods A fast imaging protocol is presented that permits the assessment of the pixel-wise full in-plane velocity information of the beating heart within a single breath-hold measurement. Temporal resolution of the acquired images is improved by the use of high-speed gradients and application of view sharing to black blood k-space segmented gradient echo imaging. A novel tool for data analysis is presented based on correlating locally different myocardial motion patterns to averaged left ventricular velocities reflecting nonpathological myocardial function. Results Measurement protocol and postprocessing options were evaluated in a study with 16 normal volunteers. Simulations showed that correlation analysis can be used to differentiate regions with altered velocity waveforms from global radial velocities. Results of patient examinations are presented on an exemplary basis and demonstrate that correlation analysis provides an effective method for identification and classification of myocardial dynamics. Conclusion Within the framework of our volunteer and patient examinations, fast phase contrast cardiac MRI has proven to be a reliable method to assess and analyze myocardial performance on the basis of two-directional velocity vector fields. J. Magn. Reson. Imaging 2002;15:642–653. © 2002 Wiley-Liss, Inc.

Isolated Noncompaction of the Myocardium A Rarity or Missed Diagnosis

Abstract: . A physical examinationwas unremarkable except for a fourth heart sound. Baselineblood studies showed mildly elevated troponin and creatinekinase-MB levels and hypercholesterolemia. A cardiac ultra-sound showed the upper limit of normal wall thickness andnormal valvular flows, biventricular size, and function. Cardiaccatheterization revealed a mildly abnormal contraction of theanterobasal wall of the left ventricle and normal epicardialcoronary vessels. Cardiac magnetic resonance imaging wasperformed to help exclude myocardial/pericardial disease.Magnetic resonance documented intramyocardial recessesof the inferior and anterobasal left ventricular (LV) wall.These recesses were in communication with the LV lumen(Figure 2, A and B). In addition, prominent trabeculationextended into the LV cavity (Figure 3). Ventricular mass,size, and systolic function were normal. There was noevidence of myocardial hyperenhancement after gadoliniuminjection. Serology was normal.These appearances are consistent with myocardial non-compaction, a congenital disorder of endomyocardial embry-ogenesis. This example is less florid than cases detailed in thelimited number of echo and pathology series currently pub-lished and, in fact, would have been missed by ultrasoundcriteria. A diagnosis of noncompaction has important impli-cations because of the need for familial screening and thepossible association with other cardiac anomalies and/ormuscle disorders, progressive LV dysfunction, risk of sys-temic embolism, and life-threatening arrhythmias. Tech-niques such as magnetic resonance imaging may improvedetection rates and provide new insights into the prevalence,spectrum, and natural course of this potentially not-so-rarecondition.

Respiratory maneuvers decrease irradiated cardiac volume in patients with left-sided breast cancer.

Abstract: Late cardiac morbidity and mortality among left breast cancer survivors treated with radiation therapy is related to cardiac volume included in the radiation portals. To determine if respiratory maneuvers can help decrease cardiac volume included in the radiation portals for left-sided breast cancer, 17 women with breast cancer, who had undergone left breast radiation therapy, underwent cardiac magnetic resonance imaging (MRI). Cardiac volume within the radiation portals was assessed from a transverse stack of eight, 10-mm thick, contiguous slices, covering the entire heart and obtained during breathholding at (1) endtidal volume (ETid) and (2) deep inspiration. Fourteen subjects (93% of those who completed the study) had inclusion of at least a portion of their heart within the radiation portals at ETid (median: 25.9 cm 3 , range 4.2 – 119.1 cm 3 ). In all subjects, inspiratory breathholding decreased irradiated cardiac volume [median change: 2 18.1 cm 3 (2 49%), p # 0:001 vs. ETid]. In 21% of patients, the entire heart could be displaced outside the

Left ventricular remodeling subsequent to reperfused myocardial infarction: evaluation of a rat model using cardiac magnetic resonance imaging.

Abstract: Purpose: This study characterized the time course of ventricular remodeling subsequent to reperfused myocardial infarction (MI) in a rat model using cardiac magnetic resonance (MR) imaging.Methods and Results: Short axis cine MR imaging was used to measure left ventricular ejection fraction (LVEF) and left ventricular volumes in Lewis rats at baseline, 1, 2, 4, 6, 8, and 10 weeks post-MI. Ventricular pressure and myocardial mass were evaluated at the 10 week time point.Results: Measurements of LVEF showed a significant decrease in cardiac function immediately after MI with no significant changes over the remainder of the time course. Measurements of left ventricular end-systolic volume (LVESV) showed significant increases over the first 4 weeks after MI with no significant changes over the remainder of the time course. Statistical analysis of the MR measurements of LVESV yielded a repeatability standard error of 3.3%, an inter-observer standard error of 3.3%, and an intra-observer standard error of 1.6%.C...

Cardiac magnetic resonance imaging of atrial septal defect for transcatheter closure.

Abstract: BACKGROUND The location, size of the defect and age of the patient are the major determining factors for transcatheter closure of an atrial septal defect (ASD). The precise shape and anatomy surrounding the defect cannot always be understood by the traditional transesophageal (TEE) echocardiographic technique. OBJECTIVES The authors compared the measurement of ASD size and atrial septal rim using cardiac Magnetic Resonance Imaging (MRI) and TEE to the balloon sizing technique and device size. PATIENTS AND METHOD Patients having an ASD which met established criteria were selected for evaluation with cardiac MRI and TEE for a closure procedure. Comparison of the ASD imaging and sizing between the different methods was made. RESULTS There were 22 patients who had complete transcatheter closure. The mean age and standard deviation of the patients was 33.2+/-15.1 (8-67) years old. The mean weight of the patients was 51.6+/-13.1 (20-99) kg. The average cardiac MRI measurement of the ASD was 24.9+/-6.4 mm compared to the TEE measurement of 20.8+/-5.5 mm. The transcatheter balloon measurement of the ASD was 25.2+/-6.9 (11-36) mm and the device closure size was 24.8+/-6.6 (11-36) mm. The correlation coefficient of cardiac MRI to device closure size was r = 0.784 (p < 0.001) when compared to TEE measurement to device closure size; r = 0.761 (p = 0.001). CONCLUSION The authors demonstrated the capability of the cardiac MRI in assessment of the ASD morphology and anatomy for transcatheter closure of the ASD with an Amplatzer Septal Occluder. Cardiac MRI can provide information about the type, location, size of the defect and direct visualization of the atrial septum anatomy. This detailed information enabled us to provide a safer, more effective application of the ASD occluder.

Apical Hypertrophic Cardiomyopathy: Clinical, Electrocardiographic, Scintigraphic, Echocardiographic, and Magnetic Resonance Imaging Findings of a Case

Abstract: The apical variant of nonobstructive hypertrophic cardiomyopathy (HCM) constitutes a minority of all cases of HCM and generally carries a favorable clinical outcome. We describe a 68 year-old Caucasian woman who presented with exertional dyspnea. The patient underwent stress testing with electrocardiogram-gated single-photon emission computed tomography imaging and resting transthoracic echocardiography. The patient also underwent cardiac magnetic resonance imaging at rest, including conventional structural and functional imaging and cine complementary spatial modulation of magnetization-tagged imaging (CSPAMM). The noninvasive evaluation of the heart demonstrated apical hypertrophy with regional systolic dysfunction, establishing the diagnosis of apical HCM. This case suggests a potential value of CSPAMM in characterizing apical HCM.

The role of cardiac magnetic resonance imaging in antiphospholipid syndrome.

Abstract: 2658 A 28-year-old woman presented to another hospital with 24 hours of right-side numbness followed by weakness. She was previously healthy until 8 months earlier, when she had developed transient (20 min) right eye vision field defects and was treated for ocular migraines. She had a second episode 6 weeks prior to admission. She has been taking oral contraceptives for the last 2 months. On admission, she had a systolic ejection murmur at apex and right hemiparesis. Magnetic resonance imaging (MRI) of the brain was positive for multiple acute infarctions involving supratentorial brain and left cerebellum. Echocardiography showed mitral valve vegetation and a multilobulated 0.5 × 1 cm right atrial mass, which was interpreted as thrombus, even though an atrial myxoma was not completely excluded. Her laboratory tests were remarkable for thrombocytopenia (122 × 109/l), positive lupus anticoagulant test, and IgG anticardiolipin antibody > 80 GPL. Ten days after the admission, despite full dose anticoagulation with low molecular weight heparin, she developed expressive aphasia and she was transferred to our hospital. The brain MRI confirmed a new stroke involving the left lentiform nucleus and thalamus (Figure 1A, axial T2 weighted image), and left parietal lobe ischemia, which is prominent by diffusion imaging technique (Figure 1B). Electrocardiography (ECG) gated spin echo MRI in the coronal (Figure 2A), sagittal (Figure 2B), and axial (Figure 2C) planes and axial crosssectional fast gradient recalled echo (GRE) (FastCard) bright blood cardiac MRI (Figure 2D) revealed thrombus in the superior vena cava and left atrium. MRI did not reveal the right atrial mass that was initially reported with echocardiography. The antiphospholipid syndrome (APS) is a distinct clinical syndrome associated with vascular thrombosis and/or pregnancy morbidity in the presence of circulating antiphospholipid antibodies, most commonly anticardiolipin antibodies and lupus anticoagulant1. Intracardiac thrombus formation can occur in patients with APS and can be difficult to differentiate from intracardiac tumors such as myxoma. Timely detection of the thrombosis is crucial in the management of APS. Cardiac MRI, which has steadily improved since its introduction 15 years ago, is one of the new diagnostic tools for the detection of thrombi. Today, cardiac MRI already has many clinical indications, Images in Rheumatology

Can cardiac magnetic resonance imaging reliably differentiate between benign and neoplastic fat

Abstract: Magnetic resonance imaging is currently frequently used to differentiate lipomatous hypertrophy of the interatrial septum from other cardiac lesions involving abnormal fatty tissue including lipomatous neoplasms. This report discusses potential problems with this approach by emphasizing the variable appearance of lipomatous hypertrophy of the interatrial septum on magnetic resonance imaging.

Occult Anomalous Pulmonary Venous Drainage The Clinical Value of Cardiac Magnetic Resonance Imaging

Abstract: A 59-year-old male with hypertension, who had occasional chest pressure with moderate activities, was evaluated for an abnormal ECG showing right bundle branch block and left-axis deviation. A transthoracic echocardiogram revealed a mildly hypertrophied left ventricle with good systolic function. The right atrium and ventricle were inexplicably dilated; the latter was contracting satisfactorily. There was moderate tricuspid regurgitation, with a transtricuspid gradient of 36 mm Hg. Subsequent transesophageal echocardiography failed to detect any primary tricuspid valve anomaly or any atrial …

Parameters for characterizing diastolic function with cardiac magnetic resonance imaging

Abstract: 23 healthy subjects and 23 patients with isolated diastolic dysfunction were examined with cine magnetic resonance imaging to find new markers for the diastolic heart function. A single mid-ventricular short axis slice in the true cardiac axis was used and endo- and epicardial borders were hand drawn. Five features were applied to characterize isolated diastolic function: Irregularity marker of contraction calculated as the sum of the standard deviations of corresponding points across all frames (IRREG); slope of a linear fit to the diastolic area change (SLOPE); slope of the minimal and mean wall thickness (MINWTH/MEANWTH); shift parameter of the least-squares fit of the sigmoid Fermi-Junction (SHIFT). The parameters were corrected for through-plane motion. MINWTH, MEANWTH, and SHIFT differed significantly in both groups. These features represent promising objective parameters to discriminate patients with diastolic dysfunction from healthy subjects.

Could Cardiac Magnetic Resonance Imaging Replace Cardiac Ultrasound? Challenges from the Echocardiography Laboratory

Abstract: Echocardiography is, at present, the most widely used noninvasive technique for dynamic imaging of the heart. Cardiac magnetic resonance imaging (CMRI) offers superb image resolution and information on blood flow, as well as cardiac anatomy. It is free from problems of poor anatomical windows, which make echocardiography difficult in some patients, while technical improvements have reduced the need for extended breath-holding. The relative roles of echocardiography and CMRI in clinical cardiac care are evolving. Pohost and Biederman (1) have described CMRI as “the cornerstone of cardiac imaging in the next millennium.” Could CMRI replace echocardiography? If CMRI is to serve all cardiac imaging needs, it is useful to review the reasons clinicians request imaging studies. We reviewed the experience of our busy adult echocardiography laboratory at the University of Iowa. During the 5-month period—January through May 2000—the echocardiography lab at the University of Iowa performed 2080 transthoracic and 163 transesophageal echocardiograms (dobutamine and exercise echocardiograms are not included in these totals). We identified transthoracic and transesophageal echocardiograms performed for the following reasons: to search for a cardiac source of cerebral embolism, including a patent foramen ovale (typically requested by the Neurology Service), to search for valvular vegetations and/or myocardial abscess (usually in-patients on Cardiology or Internal Medicine services), to rule out a left atrial appendage thrombus in patients with atrial fibrillation or atrial flutter, in anticipation of electrical cardioversion (so-called “TEE-guided cardioversion,” which obviates the need for prolonged precardioversion anticoagulation, usually requested by the Cardiology Service), and to rule out aortic dissection or aortic trauma (usually requested by the Thoracic Surgery or Trauma services). In addition, we identified patients whose physicians requested examinations be performed as a portable (bedside) exam, either because the patient was considered critically ill, hemodynamically or rhythmically unstable, or because the patient was being treated with a ventilator, intra-aortic balloon counterpulsation, etc., making movement difficult.

The Future of Cardiac MRI

Abstract: Cardiac magnetic resonance imaging (MRI) is the newest noninvasive imaging technique to be used for the evaluation of patients with ischemic heart disease (1–3). MRI can be used to study myocardial viability, myocardial ischemia, cardiac function and metabolism, and coronary artery anatomy and flow (4). The recent scientific and clinical advances have been such that several small medical societies have started to focus almost exclusively on cardiovascular MRI (5). Each year the North American Society for Cardiac Imaging (www.nasci.org), the Society for Cardiovascular Magnetic Resonance (www.scmr.org), the Council on Cardiovascular Radiology of the American Heart Association and the International Society of Magnetic Resonance in Medicine organize multiple educational events to instruct imagers and practitioners (mostly radiologists and cardiologists) about the potential value of cardiac MRI for patients with ischemic heart disease. In 1999 the Committee for Cardiovascular Imaging, a joint effort of the American College of Radiology, the Radiological Society of North America, the American Roentgen Ray Society, and the American Board of Radiology, was created to address this renewed interest from the radiology community in cardiovascular imaging. One of the first actions of the committee was to create new courses on cardiovascular imaging which are being offered four times a year throughout the United States, with the first one held in June 23–25, 2000, in Chicago (www.acr.org). Recent dramatic improvements in the technology (i.e., newer and better cardiac MRI pulse sequences) and the efforts to teach the performance of coronary magnetic resonance angiography (MRA) to more end-users (radiologists and cardiologists) are both important. For a variety of reasons most practitioners and imagers are often reluctant to utilize cardiac MRI in the routine workup of patients with ischemic heart disease. In general, these physicians lack exposure to and training in cardiac MRI. Furthermore, these examinations are technically difficult and there is the need for cardiac gating which lengthens the duration of the MR study setup time. Large clinical studies which may prove the utility of MRI for ischemic heart disease are only now being performed or planned. But most important perhaps, as pointed out by Higgins (4), a key component of the MR evaluation of ischemic heart disease, namely coronary MRA, has not yet reached a sufficient level of technical maturity. Unfortunately, cardiac MRI technology is evolving so fast that most clinical trials cannot be completed before a technique becomes obsolete, thus creating the perception that the technology is not mature. Coronary MRA is one of the best examples of such recent technological evolutions in cardiac MRI. The early coronary MRA techniques appeared very promising (6), but because they acquired only one image per breathhold, were limited to 2-D acquisitions and required operator skills. These techniques never gained widespread use (7–9). Improved coronary MRA techniques employing navigator echoes, also referred to as “second-generation coronary MRA techniques,” followed, and allowed freebreathing and increased spatial resolution followed (10–13). Later, third-generation techniques allowed the acquisition of a 3-D volume within one breathhold (14). Hybrid techniques offer the greatest hope for fast and efficient coronary MRA with adequate spatial and temporal resolution (15–17). Although these newer coronary MRA techniques are nearly as easy to employ as a conventional computed tomography (CT) scanner, the average practitioner is not comfortable with this constant change and evolution in MR techniques. The use of cardiac MRI for the direct evaluation of myocardial viability and myocardial ischemia has seen a similar dramatic evolution. Cardiac MRI has become such a vast field that it is impossible to make general statements about its future, except to say that its importance will keep increasing. Cardiac anatomy, function and myocardial viability evaluation are all very important applications, and will one day be part of the “one-stop” noninvasive comprehensive cardiac MRI examination (2,18). In this chapter we will limit our comments about the future of cardiac MRI to those that relate to coronary vessels.