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Scott D Flamm

Publications and source records attributed to Scott D Flamm.

At least 19 recordsLinked to original sources
PubMed2006

Automatic identification of the left ventricle in cardiac cine-MR images: dual-contrast cluster analysis and scout-geometry approaches.

PURPOSE: To evaluate the technical feasibility of two approaches--dual-contrast (DC) cluster analysis, and scout geometry (SG)--for automatic identification of the left ventricular (LV) cavity in short-axis (SA) cine-MR images. MATERIALS AND METHODS: The DC algorithm uses Fuzzy C-Means (FCM) cluster analysis of SA images from a black-blood double-inversion recovery turbo spin-echo (dual IR TSE) sequence, and bright-blood images from a steady-state free precession (SSFP) sequence. The SG algorithm employs geometric information from scout views (i.e., vertical long-axis (VLA) and four-chamber (4CH) views). Both algorithms incorporate additional geometric continuity constraints along with LV region segmentation to identify the LV. The performance of both algorithms was compared on images of eight healthy volunteers, and the SG algorithm was further evaluated on images of 13 clinical patients. RESULTS: The DC algorithm identified the LV in 89% (72/75 at end-diastole (ED) and 47/59 at end-systole (ES)) of the images from healthy volunteers, compared to 98% (74/75 at ED and 57/59 at ES) by the SG algorithm. Both methods are robust against interslice signal variations and misalignment. The DC method suffers from misregistration between the dual IR TSE and SSFP images near the apex at ES. The SG method identified the LV in 91% (112/122 at ED and 91/102 at ES) of the images from clinical patients. CONCLUSION: The SG method requires no additional scan, is robust and accurate, and performs better than the DC method for automatic identification of the LV.

Adult↗
PubMed2006

Tissue characterization of myocardial infarction using T1rho: influence of contrast dose and time of imaging after contrast administration.

PURPOSE: To determine whether contrast between acutely infarcted and normal myocardia in T1-rho-weighted cine TFE (T1rho-TFE) and delayed-enhancement (DE) images (measured using a metric percent enhancement (PE)) varied with the dose or time of imaging after contrast administration. MATERIALS AND METHODS: Eighteen patients with acute myocardial infarction (AMI) were randomly divided into three groups according to the dose of gadoversetamide (0.1, 0.2, or 0.3 mmol/kg) administered. After contrast administration, T1rho-TFE images were acquired at five and 40 minutes, and DE images were acquired at 10 and 30 minutes. RESULTS: For T1rho-TFE imaging the PE values at 40 minutes were 70+/-14, 98+/-14, and 105+/-41 at 0.1, 0.2, and 0.3 mmol/kg dose levels, which were significantly greater than the corresponding PEs at five minutes after contrast administration (44+/-12, 71+/-14, and 36+/-13). For DE and T1rho-TFE imaging the dose of contrast agent did not significantly affect the PE. However, with DE the PE tended to increase with the dose. At all dose levels, irreversible injury was more conspicuous in T1rho-TFE images acquired at 40 minutes than at five minutes after contrast. CONCLUSION: In T1rho-TFE, acute infarction was more conspicuous in images acquired at a later time point, and the PE did not vary with the contrast dose.

Contrast Media↗
PubMed2006

SENSE or k-MAG to accelerate free breathing navigator-guided coronary MR angiography.

OBJECTIVE: The purpose of this study was to assess the relative merits of reducing the scanning time of navigator-guided (NAV) coronary MR angiography by including, both independently and in combination, two time-saving strategies: k-space weighted motion-adapted gating (k-MAG) and sensitivity encoding (SENSE, factor = 2). SUBJECTS AND METHODS: Coronary arteries of 21 healthy subjects were imaged with four NAV MR angiography sequences: conventional NAV sequence, NAV with the addition of SENSE, NAV with the addition of k-MAG, and NAV with a combination of SENSE and k-MAG. All imaging parameters including the magnetization preparation schemes, prescribed spatial resolution, and acquisition duration per R-R interval were identical for all techniques. The total scanning time, navigator efficiency, visible length of the coronary artery, and subjective image quality were used as metrics for evaluating the performance of the techniques. RESULTS: The results show that the addition of k-MAG to NAV coronary MR angiography (with or without SENSE) improved scan efficiency and decreased scanning time by an average of 17% without compromising the length of coronary artery visible or the image quality. The addition of SENSE to the NAV technique (with or without k-MAG) reduces the scanning time by an average of 50%. CONCLUSION: While the average image quality of coronary arteries was unaffected by the addition of k-MAG to navigator techniques, there was a slight reduction in image quality scores for the navigator sequence with SENSE. Identification of the proximal coronary arteries was not hampered by the addition of k-MAG, SENSE, or both to the NAV coronary MR angiography sequence.

Adult↗
PubMed2006

Fast 3D cine steady-state free precession imaging with sensitivity encoding for assessment of left ventricular function in a single breath-hold.

OBJECTIVE: This study compares single breath-hold 3D cine steady-state free precession (SSFP) MRI using sensitivity encoding (SENSE) with standard 2D cine SSFP imaging in the quantitative evaluation of global left ventricular (LV) function. MATERIALS AND METHODS: The LV function of 22 healthy volunteers and 15 patients was evaluated using a standard 2D SSFP sequence and a 3D SSFP sequence with SENSE at 1.5 T. Ventricular volume, ejection fraction, and LV mass were calculated with each method, and signal-to-noise ratios (SNRs) and myocardium-to-blood contrast-to-noise ratios (CNRs) were measured. Agreement between the two methods was assessed using Bland-Altman analysis, and results were compared using a paired Student's t test (p < 0.05). The local institutional review board approved the study protocol, and all participants gave signed informed consent. The study complied with the Health Insurance Portability and Accountability Act. RESULTS: Both techniques produced similar estimates of ejection fraction (mean bias +/- SD, -1.2% +/- 3.6%) and LV mass (mean bias, +/- SD-1.2 +/- 10.9 g). No significant differences were found in calculated volumes, ejection fraction, or LV mass between the two methods. Acquisition time was reduced by 82%, to a single breath-hold (18 +/- 3 seconds), with the 3D SSFP technique. SNR and CNR were significantly lower with the 3D method than with the standard method. CONCLUSION: Three-dimensional SSFP imaging with SENSE can reduce acquisition time to a single breath-hold and can provide LV function quantification comparable to that obtained with conventional 2D SSFP imaging.

Adult↗
PubMed2006

Arrhythmogenic right ventricular dysplasia: initial presentation in a middle-aged woman.

Arrhythmogenic right ventricular dysplasia is a rare disorder that is familial in 30% to 50% of cases. It is characterized by structural and functional abnormalities of the right ventricle and a propensity for ventricular arrhythmias and sudden death. We report the case of a 59-year-old woman who had idiopathic, severe, right-sided heart failure and nonsustained ventricular tachycardia. She was diagnosed with arrhythmogenic right ventricular dysplasia by means of cardiac magnetic resonance imaging. We discuss the clinical features, diagnostic criteria, and role of cardiac magnetic resonance imaging in the diagnosis of arrhythmogenic right ventricular dysplasia.

Arrhythmogenic Right Ventricular Dysplasia↗
PubMed2005

Quantitative assessment of left ventricular function: steady-state free precession MR imaging with or without sensitivity encoding.

Quantitative left ventricular (LV) function was assessed with magnetic resonance imaging in 20 patients by using standard multisection multiphase steady-state free precession (SSFP) imaging and sensitivity encoding (SENSE)-accelerated cine SSFP imaging with identical spatial, contrast, and temporal resolution. The local institutional review board approved the protocol, and all patients gave signed informed consent prior to imaging. The study complied with the Health Insurance Portability and Accountability Act. Results of Bland-Altman analysis showed that both techniques produced similar estimates of LV ejection fraction, LV mass, and blood-to-muscle contrast and demonstrated minimal interobserver variability. The authors showed that it is possible, by combining SENSE with cine SSFP imaging, to reduce acquisition time by 50% without compromising spatial resolution, temporal resolution, or blood-to-muscle contrast-to-noise ratio compared with those achieved by using SSFP imaging without SENSE for quantitative LV function assessment.

Adult↗
PubMed2005

Role of noninvasive testing in the clinical evaluation of women with suspected coronary artery disease: Consensus statement from the Cardiac Imaging Committee, Council on Clinical Cardiology, and the Cardiovascular Imaging and Intervention Committee, Council on Cardiovascular Radiology and Intervention, American Heart Association.

Cardiovascular disease is the leading cause of mortality for women in the United States. Coronary heart disease, which includes coronary atherosclerotic disease, myocardial infarction, acute coronary syndromes, and angina, is the largest subset of this mortality, with >240,000 women dying annually from the disease. Atherosclerotic coronary artery disease (CAD) is the focus of this consensus statement. Research continues to report underrecognition and underdiagnosis of CAD as contributory to high mortality rates in women. Timely and accurate diagnosis can significantly reduce CAD mortality for women; indeed, once the diagnosis is made, it does appear that current treatments are equally effective at reducing risk in both women and men. As such, noninvasive diagnostic and prognostic testing offers the potential to identify women at increased CAD risk as the basis for instituting preventive and therapeutic interventions. Nevertheless, the recent evidence-based practice program report from the Agency for Healthcare Research and Quality noted the paucity of women enrolled in diagnostic research studies. Consequently, much of the evidence supporting contemporary recommendations for noninvasive diagnostic studies in women is extrapolated from studies conducted predominantly in cohorts of middle-aged men. The majority of diagnostic and prognostic evidence in cardiac imaging in women and men has been derived from observational registries and referral populations that are affected by selection and other biases. Thus, a better understanding of the potential impact of sex differences on noninvasive cardiac testing in women may greatly improve clinical decision making. This consensus statement provides a synopsis of available evidence on the role of the exercise ECG and cardiac imaging modalities, both those in common use as well as developing technologies that may add clinical value to the diagnosis and risk assessment of the symptomatic and asymptomatic woman with suspected CAD.

Coronary Artery Disease↗
PubMed2005

Isolated ventricular non-compaction in adults with idiopathic cardiomyopathy: cardiac magnetic resonance and pathologic characterization of the anomaly.

Non-compaction of the ventricular myocardium is an anomaly of myocardial morphogenesis that leads to persistence of the embryonic myocardium with an excessively prominent trabecular meshwork and deep intertrabecular recesses. This report describes 3 cases of isolated left ventricular non-compaction in adults leading to terminal heart failure. We describe their distinctive myocardial histopathology and prospective diagnosis by cardiac magnetic resonance imaging (CMR). Heart transplantation was the only treatment option for all 3 of these severely ill patients. Isolated ventricular non-compaction should be considered in patients with severe idiopathic cardiomyopathy whose symptoms appear in early adulthood, and consideration given for early transplantation. Non-invasive imaging with CMR can confirm the diagnosis.

Adult↗
PubMed2005

Orthotopic heart transplantation in a patient with D-transposition of the great arteries: after a Mustard procedure.

During heart transplantation, the atrial septum is most often used to reconstruct the right atrial reservoir. We report the case of a patient with corrected D-transposition of the great arteries who underwent successful cardiac transplantation despite the lack of an atrial septum. We then used the donor heart's atrial septum for the roof of the left atrium and used the recipient's left atrium for the back wall of the left atrium. The outcome was a more anatomically positioned transplanted heart, which avoided the duplication of the right and left atria that occurs in conventional orthotopic transplantation and that often leads to left-lower-lobe atelectasis and tricuspid regurgitation. This method of orthotopic transplantation should be considered for, but not limited to, the growing number of adults with congenital heart disease who require heart transplantation.

Adult↗
PubMed2004

Role of MRI in clinical cardiology.

Rapid progress has been made in cardiac MRI (CMRI) over the past decade, which has firmly established it as a reliable and clinically important technique for assessment of cardiac structure, function, perfusion, and myocardial viability. Its versatility and accuracy is unmatched by any other individual imaging modality. CMRI is non-invasive and has high spatial resolution and avoids use of potentially nephrotoxic contrast agent or radiation. It has been extensively studied against other established non-invasive imaging modalities and has been shown to be superior in many scenarios, particularly with respect to assessment of cardiac and great vessel morphology and left ventricular function. Furthermore, its clinical use continues to expand with increasing experience and proliferation of CMRI centres. As worldwide prevalence of cardiovascular disease continues to rise, CMRI provides opportunity for improved and cost-effective non-invasive assessment. Continued progress in CMRI technology promises to further widen its clinical application in coronary imaging, myocardial perfusion, comprehensive assessment of valves, and plaque characterisation.

Aortic Diseases↗
PubMed2004

Acute myocardial infarction: tissue characterization with T1rho-weighted MR imaging--initial experience.

Acute myocardial injury was evaluated in 21 patients by using a contrast material-enhanced T1rho-weighted cine turbo field-echo magnetic resonance (MR) imaging sequence and a delayed-enhancement sequence. In 12 of 21 patients, conventional T1-weighted contrast-enhanced cine turbo field-echo MR images were also collected for direct comparison with T1rho-weighted images. Delayed-enhancement technique distinctly characterized irreversible injury (percentage enhancement, 588% +/- 344). With T1rho weighting, percentage enhancement of irreversibly injured myocardium was 68% +/- 41, compared with 23% +/- 24 without T1rho weighting (P <.006). The addition of T1rho weighting to contrast-enhanced cine turbo field-echo MR sequences may offer a new contrast enhancement mechanism for characterization of acutely infarcted myocardium.

Adult↗