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Background and purpose: Paradoxical embolism through a patent foramen ovale is a contributory mechanism to stroke and may be diagnosed by contrast echocardiography. The intracranial distribution of these emboli has not been previously reported. Methods: We used transcranial Doppler combined with agitated saline contrast injection to determine whether there was a preferential distribution of the contrast into the anterior or posterior intracranial circulation of patients with an acute stroke or transient ischemic attack. Results: Forty-nine patients were studied—27 men and 22 women, with a mean age of 62.7 ± 13.3 years (range, 29 to 85 years). Microcavitations were detected in the proximal right middle cerebral artery in 12 of 49 patients (24%). A patent foramen ovale was confirmed in all cases by simultaneous transesophageal echocardiography. Of the 12 patients, microcavitations were also detected in the proximal basilar artery in nine (75%). Conclusions: While paradoxical embolism appears to occur more frequently in the anterior circulation, the high rate of detection of microcavitations in the basilar artery suggests that paradoxical embolism to the posterior intracranial circulation may be more frequent than generally believed.

To determine and compare the prevalence of patent foramen ovale in patients with stroke of undetermined origin (cryptogenic) and in patients with stroke of determined origin to assess the possible role of patent foramen ovale as a risk factor for cryptogenic stroke.Cross-sectional study with nested case-control analysis.A total of 146 patients (73 men, 73 women) with acute ischemic stroke referred to the echocardiography laboratory for evaluation.Neurovascular Unit and Echocardiography Laboratory, Columbia-Presbyterian Medical Center, New York, New York.Patients were considered to have strokes of determined origin or cryptogenic strokes according to National Institute of Neurological Disorders and Stroke (NINDS) Stroke Data Bank criteria. The presence of patent foramen ovale was assessed by contrast echocardiography, performed blinded for type of stroke. The association between patent foramen ovale and type of stroke was tested after correcting for patients' demographic variables and stroke risk factors.The overall prevalence of patent foramen ovale was 26 of 146 patients (18%; 95% Cl, 11.4% to 24.6%). Patients with cryptogenic stroke (31%) had a significantly higher prevalence of patent foramen ovale than did patients with an identifiable cause of stroke (69%) in both the younger (less than 55 years; 48% compared with 4%; P less than 0.001) and the older (greater than or equal to 55 years; 38% compared with 8%; P less than 0.001) age groups. Multiple logistic regression analysis was used to identify the presence of a patent foramen ovale as strongly associated with the diagnosis of cryptogenic stroke (odds ratio, 7.2; Cl, 2.4 to 21.7), irrespective of patient age and other stroke risk factors.Patients with cryptogenic stroke have a higher prevalence of patent foramen ovale than patients with stroke of determined cause in all age groups, even after correcting for the presence of recognized stroke risk factors. This identifies patent foramen ovale as a risk factor for cryptogenic stroke. Regardless of patient age, contrast echocardiography should be considered when the cause of stroke is unknown.

To determine the serial changes in T1 and T2 relaxation times of myocardial infarction, and their relationship to observed changes in water content, regional myocardial blood flow, and histopathology, rabbits were studied at 14 time intervals ranging from 30 min to 6 months after coronary artery ligation. All values were compared to a control group. Hearts were subdivided into infarct and normal segments for measurement of blood flow, water content, and relaxation times (20-MHz spectrometer); other hearts were excised intact for histopathologic studies. T1 relaxation time of infarcted myocardium did not change significantly compared to control over the 6-month study period. T2 relaxation time increased (P < 0.0001) at 3 days and returned to baseline by 2 months. Consonant with the increase in T2 of infarct, nuclear magnetic resonance (NMR) images at 3 days demonstrated an increase in signal intensity of infarct compared to surrounding normal myocardium. At 6 months, marked myocardial thinning was observed without changes in signal intensity. Changes in T2 of infarcted myocardium were not related to changes in water content or seventy of ischemia, but correlated best with infarct healing and scar formation as detected on histopathology. In conclusion, the findings of this study indicate that T2 relaxation time of the infarcted myocardium increases markedly at 3 days and remains elevated for 2 months. These changes correlate best with the onset and progression of infarct healing. These data demonstrate the potential of T2-weighted NMR imaging for assessing healing patterns following ischemic myocardial injury. © 1988 Academic Press, Inc.

To identify better those subgroups of pacemaker recipients who will benefit from dual chamber pacing, 19 patients with DDD pacemakers that were physiologically paced were entered into a blinded, randomized protocol comparing long-term VVI versus DDD pacing. Patients were evaluated in each of the pacing modes for exercise performance, cardiac chamber size, cardiac output, functional status and health perception. Eight patients (42%) insisted on early crossover, from VVI to DDD pacing, after only 1.8 +/- 1.4 weeks because of symptoms consistent with pacemaker syndrome. Overall, 12 patients preferred DDD pacing and no patient preferred VVI pacing (p = 0.001). Percent fractional shortening (30 +/- 8 vs 24 +/- 6%, p = 0.009) and cardiac output (6.3 +/- 2.6 vs 4.4 +/- 2.2 liters/min, p = 0.0001) where significantly greater in the DDD mode. Exercise duration was greater during DDD compared with VVI pacing (11.3 +/- 3.7 vs 10.1 +/- 3.7 minutes, p = 0.006). However, it was only in the crossover subgroup that DDD pacing resulted in significant improvement in exercise performance and health perception compared with VVI pacing. This subgroup of patients was characterized by an intrinsic sinus rate of less than 60 beats/min (4/8 vs 0/11, p = 0.006), ventriculoatrial (VA) conduction (4/8 vs 1/11, p = 0.048), greater increase in exercise peak systolic blood pressure from VVI to DDD mode (21 +/- 12 vs 4 +/- 13 mm Hg, p = 0.02) and greater improvement in exercise capacity from VVI to DDD pacing (2.2 +/- 1.2 vs 0.6 +/- 1.4 minutes, p = 0.03) compared with the other 11 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

SummaryThe presence of a patent foramen ovale has been found to be associated with an increased risk of ischemic stroke of otherwise unknown origin (cryptogenic stroke). The present article will review the evidence regarding this association, the technical aspects of PFO detection, and the preventive options to decrease the risk of recurrent cerebral events.

Objectives. The purpose of this study was to investigate left atrial appendage size, function and thrombus prevalence in patients with atrial “fibrillation-flutter.” Background. Thrombus formation and peripheral embolization in atrial fibrillation are related to left atrial appendage dysfunction. Embolization occurs less frequently in atrial flutter. It is not known whether the atrial appendage in fibrillation-flutter, which has an intermediate appearance on the surface electrocardiogram (ECG), has distinct characteristics that could affect thrombus formation. Methods. Sixty-one patients with atrial tachyarrhythmias underwent transesophageal echocardiographic examination of the left atrial appendage. Appendage area, peak emptying velocity and the presence of thrombus and spontaneous echo contrast were determined. The results for 14 patients with fibrillation-flutter (based on ECG fibrillatory wave characteristics) were compared with those for 30 patients with atrial fibrillation and 17 patients with atrial flutter. Results. Both fibrillation-flutter and atrial fibrillation were associated with chaotic appendage flow patterns with similarly low peak emptying velocities (18 ± 8 and 17 ± 10 cm/s, mean ± 1 SD, respectively). Atrial flutter was associated with a regular pattern of appendage contraction and a significantly higher peak emptying velocity (42 ± 18 cm/s, p < 0.0001). Mean appendage area was similar for fibrillation-flutter and fibrillation (6.3 ± 2.2 and 6.7 ± 2.1 cm2, respectively) but was significantly smaller for atrial flutter (5.3 ± 1.4 cm2, p < 0.05). The prevalence of left atrial appendage thrombus was similar for fibrillation-flutter and atrial fibrillation (40% and 29%, respctivdy), whereas no patient with atrial flutter had a thrombus (p < 0.05). Similarly, the presence of spontaneous echo contrast was higher for fibrillationflutter (50%) and atrial fibrillation (40%) than for atrial flutter (6%, p < 0.05). Conclusions. Left atrial appendage size and function in atrial fibrillation-flutter are indistinguishable from those of typical atrial fibrillation, and the frequency of thrombus and spontaneous echo contrast is similarly high. This is in contrast to atrial flutter, which is characterized by a smaller, more contractile left atrial appendage and a lower frequency of thrombus and spontaneous echo contrast.

Probability analysis has been advanced as a means of selecting patient-test combinations that most efficiently lead to a diagnosis in patients with suspected coronary artery disease (CAD). 1 Results of exercise cardiovascular nuclear medicine tests have yielded the greatest shifts in disease likelihood among patients with intermediate pretest likelihoods for disease. Furthermore, the differences in posttest probability produced by nuclear and electrocardiographic exercise tests are greatest among patients with intermediate pretest likelihoods for disease. However, when we examined the actual use of exercise thallium scintigraphy, most patients referred by both house staff and attending physicians had either very high or low pretest likelihoods for disease. 2 One explanation for these ordering practices is a lack of familiarity with probability analysis. 3 Alternatively, the clinical efficacy of a test may not be valued in proportion to its ability to alter disease likelihood. For example, exercise thallium scintigraphy has been advocated as a valuable means of excluding significant coronary disease, particularly when the pretest likelihood for coronary disease is relatively low. 4 In this study we asked house staff to calculate the predictive value of an exercise thallium test result. We then examined the relation between likelihood estimates and stated preferences for testing in an attempt to discover motivations for test ordering in actual practice.

Cardiac and noncardiac side effects were studied in 293 consecutive patients referred for nonexercise stress thallium imaging with intravenous dipyridamole. Six minutes after the initiation of infusion, there was a mean 9-beat/min increase in heart rate and a mean 12-mm Hg decrease in systolic blood pressure. The largest increase in heart rate exceeded 20 beats/min in only 13% of patients and the largest decrease in systolic blood pressure exceeded 20 mm Hg in 31%. Noncardiac side effects were headache (11%), lightheadedness or dizziness (5%) and nausea (4%). Only 9 patients required intravenous aminophylline for relief of noncardiac side effects: severe headache in 7 and nausea in 2. Cardiac side effects included chest pain in 76 patients (26%), of whom 70% were given aminophylline for relief of symptoms. Sixty patients (20%) had ischemic ST-segment depression and 56 (19%) had arrhythmias (ventricular in 50 and atrial in 6). There were no deaths, myocardial infarctions or sustained arrhythmias due to dipyridamole administration. Among 62 patients also undergoing cardiac catheterization, side effects except for arrhythmias were unrelated to the number of vessels with coronary artery disease. Intravenous dipyridamole is safe for nonexercise stress testing and has few serious side effects. However, the possibility of ischemia requires careful selection of patients and monitoring of vital signs and the electrocardiogram during the test.

Stress thallium imaging with intravenous dipyridamole permits assessment of coronary artery disease (CAD) without the need for exercise. However, intravenous dipyridamole is available in the United States only on an experimental basis. To study the use of oral dipyridamole as a clinically available alternative to intravenous dipyridamole for this purpose, 100 patients underwent thallium imaging with oral dipyridamole. Each patient received 300 mg of pulverized tablets in a 30-ml suspension. Maximal increase in mean heart rate and decrease in mean blood pressure occurred 30 minutes after ingestion. At 45 minutes, 2 mCi of thallium was given intravenously and serial imaging was begun within 7 minutes. The serum dipyridamole level (mean ± standard deviation) 45 minutes after 300 mg was administered orally (3.7 ± 2.2 μg/ml) was similar to that 5 minutes after 0.56 mg/kg was given intravenously (4.6 ± 1.3 μg/ml). Fifty-five patients had some adverse effects between 15 and 75 minutes after oral ingestion, including nausea, headache, dizziness, chest pain (25 patients) and electrocardiographic changes (14 patients). Intravenous aminophylline was used to resolve these adverse effects in 21 patients. There were no severe arrhythmias, myocardial infarctions or deaths. Of the 43 patients with angiographically documented CAD, 39 had an initial perfusion defect that redistributed on the delayed images. When the results in patients who had undergone catheterization were analyzed by individual segment, the presence of thallium redistribution was associated with normal or hypokinetic contrast left ventriculographic wall motion of that segment, whereas the presence of a persistent defect was associated with akinesia or dyskinesia (Fisher's standardized Z = 9.14). In conclusion, stress thallium imaging without exercise is feasible with a clinically available form of dipyridamole—the oral suspension. It is safe and may be used for evaluation of CAD to unmask regions of hypoperfused viable myocardium.

Non-invasive quantification of regional left ventricular (LV) deformation is crucial for the identification of clinical and subclinical myocardial dysfunction in various conditions. Several software tools now exist to provide regional LV strain estimation for echocardiography images. In this paper, we experimentally investigated the impact of real-time three-dimensional (RT3D) ultrasound temporal resolution on the precision of an integrated speckle-tracking framework. We compared temporal displacement and strain profiles acquired at three different frame rates on five normal volunteers. Results showed that estimated displacement fields and regional strain measurements were more homogeneous and of larger amplitude at higher frame rates.

Presents a study for validation of real-time three-dimensional ultrasound as a diagnostic tool in patients with primary pulmonary hypertension. Dynamic analysis of the heart is performed via quantification of right and left ventricle volumes. Segmentation of ventricular cavities is performed via a deformable-model for a set of denoised frames spread over an entire cardiac cycle. Spatio-temporal denoising is carried out by brushlet analysis that has been optimized by incorporating space and time coherence. in. texture characterization. Quantitative measures for right and left ventricular ejection fraction are compared to clinical MRI of the same patients.

This paper presents a new 4D (3D+Time) expansion of echocardiographic volumes on complex exponential wavelet-like basis functions called Brushlets (see F. Meyer and R.R. Coifman, "Brushlets: a tool for directional image analysis and image compression," Applied and computational harmonic analysis, vol. 4, p. 147-87, 1997). Brushlet functions offer good localization in time and frequency and decompose a signal into distinct patterns of oriented textures, invariant to intensity and contrast range. Automatic left ventricle (LV) endocardial border detection is carried out in the transform domain where speckle noise is attenuated while cardiac structure location is preserved. Quantitative validation and clinical applications of this new spatio-temporal analysis tool are reported with results on phantoms and clinical data sets to quantify LV volumes and ejection fraction.

In cardiac image analysis, optical flow techniques are widely used to track ventricular borders as well as estimate myocardial motion fields. The optical flow computation is typically performed in Cartesian coordinates, and not constrained from a priori knowledge of normal myocardium deformation patterns. However, for cardiac motion analysis, displacements along specific directions and their derivatives are usually more interesting than 2D or 3D displacement fields themselves. In this context, we propose a general frame work on optical flow estimation along iso- value curves. We applied the proposed framework in a specific application: for endocardium tracking on cine cardiac MRI series. The endocardial surfaces tracked with the proposed algorithm were quantitatively compared with manual tracing at each frame. The proposed method was also compared to the regular Lucas-Kanade optical flow method directly applied to MRI image data in Cartesian coordinates. Quantitative comparison showed a positive improvement in average tracking errors, through the whole cardiac cycle.

Background: Vascular malformations with arteriovenous shunt components can cause significant disability, chronic pain, and functional impairment. Effective treatment may require serial procedures, yet an imaging modality optimized to control cost and reduce radiation exposure in this predominantly pediatric population has not yet been identified. Methods and Results: We describe the use of contrast-enhanced sonography as a novel tool to define vascular anatomy and localize arteriovenous shunting in a young patient with a symptomatic vascular malformation. Conclusions: This method may effectively reduce radiation exposure and cost, and additionally provide unique information about arteriovenous shunting, offering a novel imaging application for patients with these conditions. Background Vascular malformations (VM) are congenital lesions with diverse clinical manifestations. In contrast to hemangiomas, a separate category of vascular tumors which tend to involute spontaneously, VM often grow in proportion with the child but may expand at an accelerated pace [1]. VM can occur throughout the body, involve multiple vessel types, and may be localized or extensive [2]. Although criteria have been developed for classifying vascular malformations according to flow velocity and vessel type [3], diagnosis of these heterogeneous lesions remains challenging. While these abnormalities may be asymptomatic, VM become clinically important when associated with disfigurement, functional impairment, pain, infection, and serious bleeding [4,5]. These patients require treatment, which varies according to the specific lesion, its location, functional impairment, and goals of therapy. Assembly of a multi-disciplinary team is advantageous when planning therapy. Further, precise characterization of problematic lesions is critically important both in designing the approach and understanding, likely outcomes (such

Reduced left atrial (LA) function is associated with cardiovascular events including stroke. Silent brain infarct (SBI) is considered to be a precursor of symptomatic stroke, and has an overall prevalence ranging from 8% to 35% in the general elderly population. It is not known whether LA