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Scott D Flamm

Publications and source records attributed to Scott D Flamm.

36 records · Page 2Linked to original sources
PubMed2004

Coronary artery magnetic resonance angiography.

Coronary magnetic resonance angiography (coronary MRA) continues to advance rapidly from both a technical and clinical perspective. Coronary MRA has benefited directly from improvements in spatial resolution, contrast definition, and advances in motion correction, which have furthered its routine use in evaluating coronary artery bypass grafts and anomalous coronary arteries. Work in refining the techniques for more accurate identification of coronary artery disease (CAD) continues, with advances in navigator-gated and breath-hold motion correction techniques, novel k-space strategies (e.g., spiral and radial k-space filling), development and application of intravascular contrast agents, and imaging at higher field strengths. Ultimately, these developments may lead to the routine application of coronary MRA as a screening tool for CAD. This article reviews the development of coronary MRA, discusses the requirements and tools necessary for optimal visualization of the coronary arteries, and describes the application of coronary MRA to acquired and congenital CAD.

Coronary Angiography↗
PubMed2004

Cardiac sarcoidosis detected by delayed-hyperenhancement magnetic resonance imaging.

We report the case of a patient with sarcoidosis and ventricular tachycardia in whom cardiac magnetic resonance imaging provided supportive evidence of cardiac involvement by delineating regions of myocardial inflammation and fibrosis inconsistent with ischemic injury. The identification of cardiac involvement in patients with sarcoidosis is problematic, and the true incidence is unknown. Cardiac magnetic resonance imaging may help establish the actual incidence of cardiac involvement and allow further advances in monitoring and treatment options.

Cardiomyopathies↗
PubMed2003

Time-resolved contrast-enhanced magnetic resonance angiography in pediatric patients using sensitivity encoding.

PURPOSE: To evaluate the role of time-resolved contrast-enhanced magnetic resonance angiography (CE-MRA) using sensitivity encoding in imaging the thoraco-abdominal vessels in pediatric patients. MATERIALS AND METHODS: Thoraco-abdominal vessels of 22 pediatric patients (median age = 5 years) were evaluated with a 3D CE-MRA technique in combination with SENSE following a 0.2 mmol/kg injection of Gd-chelate. The acquisition parameters were as follows: TR/TE = 5/1.1 msec; flip angle = 40 degrees; in-plane phase encoding steps were reduced by a factor of 2 using sensitivity encoding (SENSE); 3D volume acquisition was repeated four to eight times consecutively during free breathing (four to eight dynamics) with a mean temporal resolution of 6.8 seconds/dynamic; and mean acquired voxel size = 1.4 x 1.7 x 3.1 mm (reconstructed as 1.4 x 1.4 x 1.55 mm). Arterial-to-venous signal intensity ratios (AVRs) were computed for each dynamic. RESULTS: All images were successfully reconstructed and were of diagnostic quality. The AVRs of prepeak, peak, and postpeak arterial volumes were 1.0 +/- 0.5, 6.1 +/- 3.3, and 1.3 +/-0.9, respectively, indicating good arterial-to-venous separation. The signal-to-noise ratio (SNR) of the peak arterial volume was 41 +/- 26. CONCLUSION: Our results suggest that it is feasible to apply SENSE to a conventional 3D CE-MRA technique in a time-resolved fashion for imaging the thoraco-abdominal vessels in pediatric patients during free breathing.

Abdomen↗
PubMed2003

Coronary arteries in crisscross heart.

Crisscross heart, or superoinferior ventricles, is a complex and often confusing congenital anomaly. We report a heretofore unreported presentation of "isolated" crisscross heart in situs inversus levocardia, which allows us to more clearly define the typical features of crisscross ventricles. The case of this 41-year-old woman, who had a peculiar coronary anatomy, underscores the concept that coronary artery anatomy is strictly related to the myocardial mass served. In complex congenital heart defects, development of an anterior descending artery is possible (as a primary artery, along with the circumflex and right coronary arteries) only if the ventricular septum develops properly and is aligned with the semilunar valves. We use the present case of crisscross heart to illustrate the spectrum of anomalies that can occur during formation of the cardiac apex; this spectrum ranges from a normal apex, to a diverted apex (as in dextroversion in situs solitus), to a crisscross anomaly.

Adult↗
PubMed2003

Surgical management of metastatic melanoma to the ventricle.

The treatment of patients who have cardiac tumors can be challenging, because these tumors occur infrequently and in variable locations, and surgical resection is often technically difficult. We report the cases of 2 patients, each of whom underwent successful surgical excision of large melanomas that had metastasized to the right cardiac ventricle. Although the presence of widespread disease and a limited life expectancy usually prevent surgical therapy for patients who have metastatic cardiac tumors, removal of such masses greatly facilitated subsequent medical management of these 2 patients and improved their quality of life.

Adult↗
PubMed2002

Assessing myocardial viability and infarct transmurality with left ventricular electromechanical mapping in patients with stable coronary artery disease: validation by delayed-enhancement magnetic resonance imaging.

BACKGROUND: This study was designed to define myocardial viability and establish practical cut-off values for differentiating normal myocardial tissue from subendocardial and transmural scar tissue by using electromechanical mapping (EMM). We validated our results by delayed-enhancement cardiac MRI (DE-MRI). METHODS AND RESULTS: We prospectively studied 15 ambulatory patients with stable coronary disease who were candidates for cardiac catheterization. Within 48 hours of EMM, DE-MRI was performed. Using EMM software, we created a bull's eye precisely matched to that generated by DE-MRI. Segment by segment, we compared the MRI results to the corresponding unipolar voltage value for that same segment in the EMM bull's eye. Of 300 total segments, 275 were compared. The segments were divided into normal (n=211), subendocardial scar (n=49), and transmural scar (n=15). We found that subendocardial (6.8+/-2.9 mV) and transmural (4.6+/-1.9 mV) scar segments had significantly less unipolar voltage than normal (11.6+/-4.5 mV) segments (P<0.05 for each comparison). When normal myocardium was compared with myocardium with subendocardial scar, the threshold for differentiating between the two areas was 7.9 mV (sensitivity, 80%; specificity, 80%). Comparison of normal tissue to transmural scar yielded a threshold of 6.9 mV (sensitivity, 93%; specificity, 88%). CONCLUSIONS: Our results demonstrate that normal myocardium can be accurately distinguished from myocardium with subendocardial or transmural infarcts on the basis of unipolar voltage values obtained through EMM. This is the first study to validate these results by using cardiac DE-MRI in humans.

Adult↗
PubMed2002

Takayasu arteritis: utility and limitations of magnetic resonance imaging in diagnosis and treatment.

OBJECTIVE: Previous studies have confirmed the poor correlation of symptoms, signs, and levels of acute-phase reactants with disease activity in approximately 50% of all patients with Takayasu arteritis (TA). Invasive angiographic studies demonstrate vessel lumen anatomy, but do not provide qualitative information about the vessel wall. Moreover, sequential invasive angiographic studies expose patients to high-dose ionizing radiation and catheter/procedure-related morbidity. The aim of the present study was to determine the utility of new developments in vascular magnetic resonance (MR) technology in patients with TA. METHODS: Electrocardiogram-gated "edema-weighted" MR was used to evaluate the aorta and its primary branches with regard to the vascular lumen, vessel wall anatomy, and vessel wall edema in 24 TA patients (77 studies). Inclusion criteria were age <50 years and features of TA on both clinical examination and invasive angiographic studies. Patients were stratified based on clinical and laboratory indications of having either unequivocally active disease, inactive disease, or uncertain disease status. RESULTS: MR revealed vessel wall edema in 94% (17 of 18), 81% (13 of 16), and 56% (24 of 43) of studies obtained during periods of unequivocally active disease, uncertain disease activity, and apparent clinical remission, respectively. Westergren erythrocyte sedimentation rate and C-reactive protein values did not correlate with either the clinical assessment of disease activity or MR evidence of vascular edema. The frequency of presumed vascular inflammation (edema), as assessed by MR, in patients who appeared to be in remission was similar to the reported frequency of new angiographic lesions and histopathologic evidence of active disease in surgical specimens from patients thought to be in remission. However, the presence of edema within vessel walls did not consistently correlate with the occurrence of new anatomic changes found on subsequent studies. CONCLUSION: Inconsistencies in the presence or absence of vessel edema and subsequent anatomic changes have cast doubt on the utility of edema-weighted MR imaging as a sole guide to disease activity and treatment in TA. In this study, the greatest utility of MR was in providing a safe, noninvasive means of assessing changes in vascular anatomy.

Adolescent↗
PubMed2002

Cardiac MRI: recent progress and continued challenges.

Cardiac MRI continues to develop and advance. MRI accurately depicts cardiac structure, function, perfusion, and myocardial viability with an overall capacity unmatched by any other single imaging modality. MRI is an accepted and widely utilized tool for cardiovascular research. Its clinical use has been limited, but is increasing because of its proven clinical efficacy, the proliferation of cardiac-capable MRI systems, and the development of improved pulse sequences. The following article reviews the landmark developments in this field, with an emphasis on recent progress in the evaluation of ischemic or acquired heart disease.

Heart↗
PubMed2002

Interrupted aortic arch in an adult single-stage extra-anatomic repair.

Interrupted aortic arch is a rare congenital malformation of the aortic arch that occurs in 3 per million live births. Defined as a loss of luminal continuity between the ascending and descending portions of the aorta, this anomaly entails a very poor prognosis without surgical treatment. To our knowledge, the world medical literature contains only 12 reports of isolated interrupted aortic arch diagnosed in adults. Nine of these patients underwent successful surgical repair, but 1 died during the early postoperative period. We describe a 10th successful surgical repair, which involved a 42-year-old woman who had an asymptomatic type B interrupted aortic arch (characterized by interruption between the left subclavian and left carotid arteries). We performed a single-stage extra-anatomic repair by placing a 16-mm extra-anatomic Dacron graft between the ascending and descending portions of the thoracic aorta and by interposing a 7-mm extra-anatomic Dacron graft between the 16-mm graft and the left subclavian artery. The patient recovered uneventfully and continued to do well 6 months later.

Adult↗
PubMed2002

Magnetic resonance imaging of myocardial fibrosis in hypertrophic cardiomyopathy.

Myocardial fibrosis can occur in patients who have hypertrophic cardiomyopathy in the absence of epicardial coronary disease. In such patients, myocardial fibrosis has been linked to a poorer prognosis than in those without fibrosis. Gadolinium-DTPA delayed-enhancement magnetic resonance imaging (de-MRI) accurately identifies regions of myocardial fibrosis. We used de-MRI to screen for myocardial fibrosis in 8 patients with nonobstructive hypertrophic cardiomyopathy that had been diagnosed by 2-dimensional echocardiography. After localization of the heart and acquisition of electrocardiographically gated cine images, gadolinium-DTPA (0.2 mmol/kg) was administered to the patient. Fifteen minutes later, de-MRI images were obtained using a T1-weighted, inversion-recovery fast, low-angle shot sequence. Images were gated to end-diastole and obtained during a single breath-hold. The inversion time was modified iteratively to obtain maximal nulling of the signal from the ventricular myocardium. Regions of myocardium with abnormally high signals (>300% of remote normal myocardium) were designated as fibrotic. Eight patients with hypertrophic cardiomyopathy underwent de-MRI. The mean age was 52 years, the mean left ventricular mass was 201 grams, and the mean ejection fraction was 0.68. In the 6 patients with recent clinical deterioration, de-MRI showed clearly delineated areas of myocardial fibrosis; no such areas were seen in the 2 asymptomatic patients. We conclude that patients with symptomatic hypertrophic cardiomyopathy display regions of abnormal signal intensity on de-MRI that likely represent fibrosis. This technique may provide useful information in the evaluation of such patients and warrants further study.

Adult↗
PubMedDate not supplied

Evaluation of a new cardiac recovery system in a bovine model of volume overload heart failure.

We evaluated the short-term hemodynamic efficacy of the Cancion cardiac recovery system (CRS) in a bovine model of volume overload heart failure. We created severe mitral regurgitation (MR) by disrupting the mitral chordae tendineae of two calves, which were allowed to survive for 13 and 11 months. Four hours before we killed the calves, we introduced the CRS, which maintained flows of 1.2 L/min. Hemodynamic data were recorded before and after MR creation and CRS initiation. Left ventriculography was performed at those same intervals and 4 hours after CRS initiation. After chordal disruption, the left ventricular end-diastolic pressure (LVEDP) increased from 14 to 23 mm Hg in calf 1 and 15 to 27 mm Hg in calf 2. After 4 hours of CRS support, the LVEDP decreased from 23 to 8 mm Hg (calf 1) and 27 to 14 mm Hg (calf 2); dP/dt increased from 1,373 to 2,900 mm Hg/s (calf 1) and 1,068 to 2,384 mm Hg/s (calf 2). MR decreased from 3+ to 1 in calf 2 but could not be determined in calf 1. In this bovine model of volume overload heart failure, the CRS unloaded the left ventricle and reduced the afterload. Future trials will determine the pump's ability to treat congestive heart failure.

Animals↗